Department of Animal, Aquaculture and Range Sciences

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The ability of sheep to reach for food through tombstone barriers, as affected by position of food, body weight and body dimensions
(2000) Muhikambele, V.R. M.; Owen, E.; Mould, F.L.; Mtenga, A.
Two studies were undertaken to provide information on the ability of sheep to reach for food similar to that for cattle fed through tombstone barriers. In the first study twenty castrate and twenty non-pregnant: female unshorn Suffolk x Mule sheep (23 - 89 kg live weight) were trained to reach through a vertical' tombstone barrierJor concentrate meal placed on a horizontal platform attached to the barrier. The barrier allowed the neck to pass through, but not the shoulders. It was hypothesised that horizontal reach forwards (F. distance from mid-point of barrier to uneaten meal) and sideways (S. distance sideways from ' mid-point of barrier to uneaten meal adjacent to barrier) would be a function of height of platform above the floor and bt size (M). Because of size. seventeen sheep (mean 34.6 kg) were unable to reach the meal when the p at form height was 75 cm. Mean (s. e.) values for F cit platform heights O. 25. 50 and 75 cm were 43.91.03. 9.40.91. 47. 00. 96 and 27.01.27 em respectively. Values for Sweresmaller but followed a similar pattern (36.61.10. 43.50.80. 41.00. 79 and 22.91.78 em). Lihearregression showed that F or S could be predicted from M (R2 >0.5) or a combination of M and withers height (R2>0. 7) when platform heights were 25. 50 or 75 cm. Reach at 0 cm platform height was not related to body weight or linear dimensions. In the second study with unshorn Suffolk x Mule sheep. ten castrates and ten non-pregnant fomales (23 - 97 kg live weight) were trained to reach through the tombstone barrier for concentrate pellets glued'. using molasses. onto a vertical plate. It was hypothesised that vertical reach (V. distance from floor to uneaten pellets) would be afunction of distance between barrier wid plate (20. 30. 40. 45. 50 cm). height of step (0. 14.2. 28.4. 42.6 cm) on which sheep placed their forelegs. and body size. With the-exception of the largest sh'eep. most were unable to reach pellets either when the barrier-to-plate distance was 45~nd 50cin. or when theforeleg-step height was 42. 6 cm. Mean (s.e) Vvaluesdecreasedwith step height (e.g. at 0 cm step. 103.83.04. 96.23.23 and 82.14.3 7cm. at 20. 30 and 40 cm plate distances respectively; at ~Ocm plate distance. 103.83.04.118.72.83 and 131.92.91 cm at O. 14.2 and 28.4 cm step heights respectively). Linear regression of V on body weight and linear dimensions (e.g. withers height and rump height) showed high correlations (R2> O. 8). V could be predicted from either M ~>O. 7) or a combination of rump height andwithers height~>0.9). The results confirm relationshipsfound in a previous investigation }'lith goats. but demonstrate that sheep have a smaller reach than goats. The data will facilitate the design of mangers for sheep with body dimensions in the range of those used.
Abundance and distribution of ixodid tick species Infesting cattle reared under traditional farming Systems in Tanzania
(African Journal of Agricultural Research, 2017) Kerario, Isack Ibrahim; Muleya, Walter; Chenyambuga, Sebastian; Koski, Marja; Hwang, Seong-Gu; Simuunza, Martin
Ticks and tick-borne diseases are serious constraints to livestock production in Tanzania and other sub-Saharan African countries. Despite this, knowledge on the abundan ce of tick species infesting cattle in most parts of Tanzania is insufficient or lacking. This study was conducted to identify species and establish the abundance of ticks infesting cattle in Mara, Singida and Mbeya regions of Tanzania. The ticks were collected from one side of the body, counted and identified, based on morphological characteristics; to species level. The mean tick count per animal was significantly higher in Mara (35.8±4.3, p=0.0001) as compared to Singida (12.9±2.1) and Mbeya (7.0±0.4) regions. Young animals in Mara (24.7±6.0, p=0.0395) and Mbeya (5.4±0.3, p=0.0252) exhibited relatively lower mean tick counts compared to the weaners (Mara = 33.8±6.5, Mbeya = 7.2±0.7) and adult animals (Mara = 46.3±8.4, Mbeya = 7.8±0.7). Seven tick species from three different genera, namely Ambylomma, Hyalomma, Rhipicephalus (including the subgenus Boophilus), were identified. However, only five species (A. lepidum, A. variegatum, R. decoloratus, R. microplus and H. rufipes) were observed in all the three regions. R. appendiculatus and R. evertsi were not found in Mbeya and Mara respectively. The most prevalent species in Mara, Singida and Mbeya were R. appendiculatus (50.5%), A. lepidum (31.2%) and R. evertsi (35.6%), respectively. This study showed the existence of a variety of tick species, most of them being of veterinary importance. Therefore, strategic planning and cost-effective tick control measures should be implemented in order to reduce losses caused by ticks and tick borne diseases in the study area.
Alkali treatment of roughages and energy utilization of treated roughages fed to sheep and goats
(University of Dar es Salaam, 1981) Ndelilio, Urio A.,
Two series of experiment were conducted, laboratory scale experiments, and and production experiments. The laboratory scale scale experiments were carried out to develop simple methods of alkali-treatment, and to test the- effectiveness of cheap alternative chemicals lo sodium hydroxide. Pro duction experiments were conducted to tost the effectiveness of an apparently promising "dip" treatment motheJ developed in the laboratory scale experiments. and k.a Ca(CII) The effectiveness of Na9CO3 emu lUn,2 cis roughage treating chemicals were tested in combination with NaOH in a 3 x 3 factorial experiment. The levels of the chemicals tested were 0, 3 and 6 g/100 g of roughage (DM). was used as a test roughage. Wheat straw Neither of the chemicals re- suited in any improvement in the digestibility of the straw’ although Ca(OII)2 showed a slight effect in increasing the enzyme soluble organic matter of wheat straw. Both chemicals showed a somewhat negative interaction with NaOH. Maize stover and Hyparrhenia grass were also treated with increasing levels of Na2COg from 0 to 10 g/100 g of roughage DM. Maize stover did not show any response to Na2CO3 treatment except for its enzyme soluble organic matter which increased with increasing levels of Na2CO3. The enzyme soluble organic matter for the untreated maize stover was 29%, while that for maize stover treated with 10 g Na2CO-/ 100 g of roughage DM was 43.6%. Hyparrhenia grass responded comparatively better to Na?CO3 treatment than maize stover. Addition of herring meal to the roughages resulted in a(X) marked improvement in the digestibility of both roughages. This also improved the response of the roughages to ^2^0^ treatment. Maize stover showed a higher response to the addition of herring meal than IJyparrhenia grass. The chemical composition of 4 samples of local Magadi soda was determined. All the samples had high sodium chloride contents, indicating a possibility of Magadi soda having a positive effect on voluntary feed intake. It was rioted that some samples had rather high fluorine contents. Studies were conducted on the effectiveness of a simple "dip" method which involved dipping straw in a 1.5% NaOH solution overnight, letting it drip, washing with minimum water, and letting it drip again. The lye solution was reused 15 times, the strength of the solution being restored after each treatment. The DM and Na content of the lye solution increased with increasing reuse of the solution. The DM content of the solution increased from 1.9% to 7.2%, while the Na content increased from 0.7 to 1.4%. Both the DM and Na contents of the solution tended to stabilize after the solution had been reused more than 10 times. The IVOMD and ESOM of the treated straw increased with increasing reuse of the solution. The in vivo DM and OM digestibility as well as DE of the straw was improved markedly by the dip method. The digestibility of OM of the untreated straw was 50% as opposed to 73% for the dip treated straw. The diges tibility of DM and OM in vivo was not affected by the reiise of the solution although that of CF tended to decrease slightly after the solution had been reused more than 10 times.(Xi ) In the production experiments a comparative slaughter technique was applied with sheep and goats. Three groups of goats were fed rations based on untreated maize cobs, "dip" treated maize cobs (NaOII-treatment) , and Chlorin gayana hay. The experimental feeding period was 100 days. The DM intake from these rations was the same in the three groups, but the dip NaOII treatment of maize cobs resulted in a higher DM digestibility (G4.1% as opposed to ) higher metabolizable energy intake (4.19 MJ as opposed to 3.40 MJ/d) when compared to the group fed untreated maize The group fed dip treated maize cobs also had sig cobs. nifleant higher gains in liveweight, carcass weight, car- cass fat, and carcass gross energy content. This group, however, did not differ significantly from the group fed Chloris gayana hay in these parameters. It was also observed that, the group fed dip treated maize cobs had a tendency to lay down intestinal fat. Three groups of sheep were also fed on untreated maize stover, dip treated maize stover and ensiled (NaOH-treated) Hyparrhenia grass silage for 100 days. centrate in the DM intake was about 20%. The level of con Although dip treat ment of maize stover increased its digestibility, this did not result in significant differences in performance between the group fed untreated maize stover in all the parameters studied. The groups fed maize stover (untreated or treated) had however significantly bettor performance in all para- meters measured than the group fed NaOII-treated Hyparrhonxa silage.(xii) CorreiaLions wore determined between whole carcass fat Z and carcass weight, and between carcass fat -i and carcass specific gravity. In goats, the correlation coefficient for carcass fat Z on carcass weight was 0.84, while that between carcass fat " and carcass specific gravity was -0.97. These para meters (carcass weight, and carcass specific gravity) can there?fore probably bo used to estimate carcass fat S and consequently carcass energy content in goats. The correlation coefficient between carcass fats and carcass weight in sheep was only 0.52, while that between carcass fat S and carcass specific gravity was -0.79. In addition to those comparatively low relationships in sheep, it was noted that carcass specific gravity was rather sen sitive and difficult to measure in fat carcasses, and liable to technical errors. It is thought that those relationships cannot therefore be applied universally to the heterogeneous sheep of East Africa.
Altered fruit eating quality in tissue culture derived off-type banana (Musa spp.)
(Journal of Applied Biosciences, 2011) Msogoya, T. J.; Grout, B. W. W.
Objective: Somaclonal variation with desirable agronomic performance has extensively been reported but studies on eating qualities of such off-type banana are limited. This study was conducted to determine eating qualities of an in vitro derived off-type banana (Musa AAA East Africa) cv. ‘Uganda’ with tolerance to black sigatoka disease and a high yielder. Methodology and Results: Uncooked and cooked mature green fruits of the off-type banana were compared with those of the popular cooking banana cv. ‘Mshale’ (AA Pisane Lilin) and cv. ‘Uganda’ based on laboratory analysis and taste interviews. Similarly, ripe fruits of the off-type banana were compared with those of the popular dessert banana cv. ‘Mtwike’ (AAA Cavendish cv. Grande naine) and cv. ‘Kisukari’ (AAB/AB Silk) based on laboratory analysis and taste interviews. Results showed that the uncooked green mature fruits of the off-type banana had higher (P < 0.05) calorific value but its cooked meal was the least (P < 0.05) accepted by the taste panelists on grounds that it was hard, less sweet and less aromatic. On the other hand, ripe fruits of the off-type banana were the sweetest with the most attractive peel colour but yet the least accepted by the taste panelists for their sweetness had a fast satiating effect. The poor acceptability of the off-type banana for both cooked and ripe fruit consumption was due to differential proportions of soluble solids caused by altered fruit ripening. Conclusion and application: The undesirable quality of the off-type banana limits not only its adoption by farmers but also the use of somaclonal variation as a source of genetic improvement of banana cv. ‘Uganda’. However, as a consequence of increased sweetness, the off-type banana fruits have the potential for use as sweetener in diet drinks, ice creams, chewing gums and cough syrups.
Alternative goat kid-rearing systems for improved performance and milk sharing between humans and offspring in climate change mitigation
(Springer International Publishing AG, 2015) Chigwa, Fanny C.; Eik, Lars Olav; Kifaro, G.C.; Muhikambele, V.C.M.; Mushi, Daniel E.
Intensification of livestock production reduces the amount of land required to sustain a livestock unit and frees up the land necessary for carbon sequestration. Transforming the goat sector from meat only to a dual-purpose system with both milk and meat is reported to increase food production per unit of land. Dairy goats have been widely adopted among smallholders in Tanzania and are now gaining popularity in Malawi. High mortalities due to poor feeding of goat- kids have been identified as a major challenge and therefore kid rearing systems of different milking systems for dairy goats and use of different creep feeds and alternate rearing systems for meat goat on Likoma Island were evaluated. In study I, the methods used were (a) suckling one teat twice daily and milking the other teat; (b) suckling in daytime only and morning-milking of dams, and (c) early weaning and bottle-rearing using goat’s milk. In study II, three different types of locally available creep feed supplements were evaluated for animals grazed on unimproved rangeland. The third study qualitative differences in kid rearing systems for local goats, with or without milking, were evaluated on Likoma Island in Malawi using a semi-structured questionnaire. In study I, kid growth rates, ranging from 62 to 76 g/day did not significantly differ; one teat milking provided the most milk for human consumption and artificial rearing was found to be the most labor intensive and therefore not recommended under small-holder condi- tions. Goat farmers on Likoma Island preferred faster kid growth to more milk for human consumption. It is concluded that successful kid rearing systems should address farmer milk utilization and kid growth and evaluate locally available feeds for creep feeding and dam feeding.
Analysis of diurnal and seasonal dynamics of water quality parameters and their implications on metabolism and physiology of nile tilapia (oreochromis niloticus) cultured in pond.
(Sokoine University of Agriculture, 2024) Hamad M. I
Aquaculture production of Nile tilapia (Oreochromis niloticus) has attracted considerable attention around the world because of their fastest growth rate, good quality meat, and fascinating physiological characteristic that allow them to adopt and strive in a broad range of production systems. Because of these characteristics, Nile tilapia has been adopted as the key aquaculture species in Tanzania. Nile tilapia production in Tanzania takes place primarily in earthen ponds, mostly under a semi-intensive system without the use of water treatment technology. In Tanzania more than 80% of the aquaculture produced fish comes from Nile tilapia raised ponds. The production of Nile tilapia in ponds has for long time been unsuccessful due to poor growth performance. This is because, unlike in other production systems such as Recirculating Aquaculture Systems (RAS), in small water bodies such as earthen ponds water quality parameters vary considerably on a daily basis, depending on the equilibrium reached with the regular physical and chemical characteristics of the surrounding environment. These variation are likely to considerablly effect physiology and welfare of the cultured fish. Unfortunatly, the extent of diurnal, and seasonal variation in water quality parameters in the production ponds across the country are not yet known. This makes it difficult for estimating the influence of changes in fish ponds water quality influences on physiology and performance of cultured Nile tilapia. This study was carried out to determine the current status and dynamics of the diurnal, and seasonal fishpond water quality parameters in Tanzania. It was also carried out to assess the effects of the observed water quality variation on the physiology, metabolism and performance of the pond-cultured Nile tilapia. To achieve the study objectives, a field survey of fish onds and three laboratory experiments were performed. The diurnal and seasonal trends in pond water quality parameters were documented and the effect of changes of some selected water quality parameters on the Nile tilapia physiological characteristics and performances were reported. Study 1. A field survey was conducted between June 2019 and April 2021 in Tanzania. Four agroecological zones (Easter, Southern Highland, Northern, and Lake Zones) were selected as study sites. A total of 120 fish farmers were interviewed using a well structured questionnaire to collect information on the current general farm characteristics and farming practices. In addition, a fish farm with identical ponds stocked with Nile tilapia was selected in each agro-ecological zone, and an in-situ measurement of the water parameters was carried out for one year, covering two seasons (the cold: June to September and the warm season November to January). Results revealed significantly difference in mean pond water temperature between the study zones (p <0.001) with the highest in the Eastern and the lowest in the Southern Highland zones. Results show that the temperature in the Northern zone and Southern highlands during the cold season (June to September) was below the level required for Nile tilapia growth. Other water quality parameters (pH, DO, turbidity, and TDS) varied between seasons within zones, but, were within the range suitable for Nile tilapia growth. The annual fish yield was higher in the Lake zone (629 ±124 kg/ha/yr) suggesting a positive relationship between temperature and fish yield. High net primary production during the warm season in all zones indicates the need for good water quality management to prevent algae blooms, which may result in acute and prolonged stress from hypoxia and hypercapnia, which are the primary physiological stressors for fish. The available data from the survey study was used as a baseline in a series of experiments conducted in the lab at Denmark Technical University (DTU-aqua) to critically assess the effects of the variation in water parameters on the physiology and performance of the cultured Nile tilapia. Experiment 1. High level s of dissolved carbon dioxide (CO 2 ) occurs nightly in earthen ponds characterized by high respiration rates. Exposure to high CO 2 conditions (hypercapnia) leads to acidosis in fish, which can be compensated by an accumulation of HCO 3- to recover intra - and extracellular pH levels, with a capacity that appears to be species-specific. For Nile tilapia, a freshwater tropical teleost traditionally produced in earthen ponds, little information is available on the tolerance to dissolved levels of CO 2 and associated acid-base disturbances. Here, we investigated first the effects of acute and progressively increasing CO 2 , from normocapnic conditions to 60 mg CO 2 L -1 , on oxygen uptake rates (MO 2 ). This was followed by exposure to three concentrations of CO 2 ; 10, 30, and 60 mg L -1 (equivalent to pCO 2 of 5.4, 16.2, and 32.4 mmHg) against a normocapnic control (pCO 2 0.3 mmHg), to investigate acute (1h) or prolonged (24h) effects on standard (SMR) and maximum metabolic rate s (MMR), haematology, and extra - and intracellular acid-base status in adult Nile tilapia (mean BM 435 ± 16 g ±SE). Acute exposure to hypercapnia led to concentration-dependent decreases in both SMR and MMR. Fish were able to fully or partially recover MMR and metabolic scope (MS) after 24h, while depression of SMR persisted at all CO 2 levels. Acute exposure to CO 2 caused intra-and extracellular pH levels to decrease by up to 0.5 units in a concentration-dependent manner. Only the lowest hypercapnic treatment (pCO 2 5.4 mmHg) was able to fully recover within 24h. Changes in haematological variables appeared minor, being restricted to increasing haematocrit, haemoglobin concentration, and mean cell volume in the highest CO 2 treatments after 24h exposure. Although the Nile tilapia is generally considered a species able to tolerate poor water quality, the modest or slow acid-base regulation following hypercapnic exposure suggests sensitivity to hypercapnia. Experiment 2. Dissolved gases (carbon dioxide and oxygen) in earthen ponds exert strong opposing effects due to photosynthesis and respiration. This leads to daily conditions that fluctuate between being hyperoxic and hypocapnic during the day and becoming severely hypoxic and hypercapnic at night. The interacting effects of hypoxia and hypercapnia and fluctuating conditions on pond-farmed Nile tilapia have not received any attention. This study evaluated the effects of daily variations in dissolved O 2 and CO 2 on the appetite and feed utilization in Nile tilapia using groups reared under normoxic - normocapnic conditions (control, C), diurnal hypoxia (HO), diurnal hypercapnia (HC), or combined diurnal hypoxia and hypercapnia (HO × HC) in a digestibility system. Results show that hypoxia and hypercapnia exerted strong individual effects on appetite, specific growth rate, and feed conversion and that simultaneous hypoxia and hypercapnia amplified these effects. Appetite depression induced by nocturnal hypoxia or hypercapnia was restored at mid-day, but simultaneous exposure resulted in a day-long loss of appetite. Hypoxia and hypercapnia reduced specific growth rates by up to 40% and increased feed conversion ratio by up to 80%, while combined exposure to hypoxia and hypercapnia reduced specific growth rates by >60%. Surprisingly, the digestibility of dry matter, protein, and lipid was improved in groups exposed to single or combined diurnal variation in dissolved oxygen and carbon dioxide. This study concludes that nocturnal exposure to hypoxia or hypercapnia has adverse effects on the growth performance of Nile tilapia driven by a combination of reductions in appetite and poor feed utilization. The results emphasize that there is a need for careful management of dissolved gases in pond culture. Application of aeration technology, combined with management of the nutrient status of the pond and sludge accumulation to control oxygen consuming and CO 2 liberating processes, is likely able to greatly improve production performance. Experiment 3. Temperature plays a significant role in controlling oxygen solubility in water and its availability to aquatic breathing species including fish. In fish ponds, the water temperature can increase gradually during the day resulting in elevated temperature and an extended period of low dissolved oxygen. In this study, the response of Nile tilapia (Oreochromis niloticus) interms of thermal tolerance limit (CTmax), metabolic rate (SMR), Cardiac performance (ƒ H ), and ventilation frequency (ƒv) to the acute increase in temperature upon changing dissolved oxygenv saturation was investigated. Nile tilapia were experimentally exposed to an increased temperature of 0.1 °C min -1 at 100% DO saturation (Normoxia), 70% (hypoxia), and 130% (hyperoxia) from 26 °C (Optimum) until the onset of loss of equilibrium (LOE). Oxygen consumption rate (MO 2 ), heartbeat, and opercula activity were averaged at each temperature increase for three DO saturation levels. Results show that high DO saturation (130%) increased Nile tilapia’s Critical Thermal Maximum (CTmax) by 10%. The Nile tilapia metabolic rate (SMR) varied significantly with the changing DO saturation at acute increased temperature levels (One-way ANOVA; F(2,44) = 4.596, P = 0.016). Temperature-DO-limited metabolic relationship affected cardiorespiratory activities and maximum thermal tolerance (CTmax) in Nile tilapia (one-way ANOVA; F (2,44) = 0.34, P = 0.713). Different levels of DO saturation were found to significantly affect Nile tilapia’s respiration ability (Opercula beats min -1 ) (P < 0.001). This study is concluding that diurnal and seasonal pond water quality varies significantly between zones and between seasons within the investigated zones and affectsthe production performance of the pond-cultured Nile tilapia. Nile tilapia might only be stocked in the warm season in the Northern and southern highland zone if farmers are to achieve the best growth of Nile tilapia. Although the Nile tilapia is generally considered a species able to adapt to and tolerate poor water quality, the modest or slow acid-base regulation following hypercapnic exposure suggests that it is quite sensitive to CO 2 exposure. Although Nile tilapia is considered resilient to environmental stress, feeding and feed utilization, oxygen uptake, and Critical thermal maximum are strongly influenced by daily fluctuations in dissolved CO 2 , O 2 and Temperature.
Analysis of genetic Diversity and relationships of Tanzania local goat populations using microsatellite DNA markers
(2002) Chenyambuga, S.W.; Watts, P.C.; Hirbo, J.; Kemp, S.J.; Hanotte, O.; Kifaro, G.C.; Gwakisa, P.S.; Rege, J.E.O.; Petersen, P.H.
Genetic diversity among seven Tanzanian goat populations (Ujiji, Sukuma, Ugogo, Maasai, Mbeya, Newala and Coastal goats) was investigated by determining polymorphisms at 19 microsatellite DNA loci, West African Dwarf Tswana, Landim and Toggenburg were included to serve as reference breeds. Among the Tanzanian populations, mean number of alleles per locus was highest (6.26 ± 0.670) in Sukuma and lowest (5.74 ± 0.545) in Newala. Gene diversity ranged from 0.553 ± 0.036 (Newala goats) to 0.646 ± 0.028 (Mbeya goats). The coefficient of gene differentiation (Gsr) indicated that 13% of the genetic diversity in all populations was due to difference between the populations. The genetic distance values ranged from 0. 068 (between Sukuma and Ugogo goats) to 0.2178 (between Ujiji and Coastal goats). The neighbour-joining dendrogram constructed to show population relationships indicated that the Tanzanian populations were separated from the populations, used as reference, breeds. The dendrogram revealed three, sub-clusters of the Tanzanian populations. Coastal and Maasai goats Ugogo and Ujiji goats and Sukuma Mbeya and Newala goats. The principal component analysis separated the Newala goats from the other Tanzanian goat populations. It is concluded that the level of genetic variation within, the goat populatiions was reasonably high and there was no significant difference between the population with respect to the number of alleles and the level of heterozygosity.
Animal health constraints in dairy goats kept under Smallholder farming systems in Kongwa and Mvomero Districts, Tanzania
(Journal of Veterinary Medicine and Animal Health, 2014) Shija, Dismas Said Ngasa; Kusiluka, Lughano Jeremy Moses; Chenyambuga, Sebastian Wilson; Shayo, Deogratias; Lekule, Faustin Paul
This study was conducted to determine animal health constraints for dairy goats kept by small-scale farmers in Kongwa and Mvomero districts, Tanzania. A total of 129 dairy goats belonging to 108 farmers were screened for gastrointestinal nematode (GIN) infection, coccidiosis, haemoparasites, brucellosis and contagious caprine pleuropneumonia (CCPP) over a period of 11 months. Other clinical diseases and mortalities were recorded. The goats used were Norwegian crosses and Toggenburg crosses. The mean prevalence of GIN infection and coccidiosis in all goats were 54.8 and 57.4%, respectively. Prevalence of GIN infection was higher (P ≤ 0.05) during the rainy months than in the dry months, but the prevalence of coccidiosis did not differ (P > 0.05) between the dry and rainy seasons. The EPG in goats did not differ (P > 0.05) between Kongwa (169.79 ± 0.03 EPG) and Mvomero (171.51 ± 0.04 EPG) districts, but the OPG differed significantly (P ≤ 0.05) with values of 793.15 ± 0.04 (Kongwa) and 364.02 ± 0.05 (Mvomero). The prevalence of CCPP in the goats was 26.4%. Other clinical diseases included respiratory diseases, infectious keratoconjunctivitis and orf (scabby lesions around mouth and nostrils). Both tests for haemoparasites and brucellosis indicated negative results for all goats tested. Mortality rate during the study period was 15.5% and the major causes of deaths were respiratory diseases, bloat and food poisoning. In conclusion, gastrointestinal nematodes are prevalent in both districts, but the burdens are relatively low to justify mass treatment. The Norwegian goats are more susceptible to GIN infection and coccidiosis compared to Toggenburg goats.
Assessment of anticholinesterase contaminants in Ruvu river using cholinesterase biomarker in African sharptooth Catfish
(Sokoine University of Agriculture, 2017) Katto, T. M.
A cross sectional study was conducted to assess the extent of exposure of anticholinesterase contaminants in Ruvu river using cholinesterase biomarker in African Sharptooth Catfish. Questionnaire interviews were used to collect sociological data from 200 respondents, also Ellman‟s method and 5, 5‟-dithiobis-2-nitrobenzoic acid chromophore was used to establish cholinesterase activities in plasma and brain of 40 Claria gariepinus. The sociological findings showed that all respondents (100%) use pesticides in agriculture and 62.5% were males with primary level of education (69%). Organophosphates pesticides were mentioned to be mostly used in the area. With regards to the proper use, awareness on the effects and disposal of pesticides, it was observed that most farmer know how to use the pesticides and were aware of the effect of pesticides in human and pests but not to the environment. Also mishandling and poor disposal of pesticides and their leftovers were reported. There was no significant difference between the levels of acetylcholinesterase (AChE) and butyrylcholinesterase (BChE) in plasma. AChE and BChE activities in brain showed insignificant difference (P > 0.05) among fish from the study sites and the control. The brain AChE activities were significantly lower (P ˂ 0.05) in fish from Ruvu Darajani compared to the control. This study revealed differences in AChE and BChE activities in the study area. Such differences could be ascribed to the environmental contamination due to agrochemicals used by the farmers around Ruvu river basin.
Assessment of body size and catch per unit effort of Nile perch (Lates Niloticus) caught using different fishing gears at Magu district in Lake Victoria, Tanzania
(African Journal of Biological Sciences, 2020) Munubi, Renalda N.; Nyakibinda, Julitha N.
Effort (CPUE) of Nile perch (Lates cf. niloticus) captured using three common fishing gears at Magu district in Tanzania. Three landing sites along Lake Victoria were selected for this assessment. Each site was visited twice per week for two months. At each site 10 boats were identified based on the gear used and randomly selected for fish count. Ten fish per boat were taken for weight and length measurements. The results show that the main fishing gears used to catch fish at all sites were gillnet (GN), long line (LL) and beach seine (BS). Mean length of captured fish recorded from each gear were 33.7, 41.5 and 43.8 for beach seine, gillnets and long lines respectively, which was below the minimal required length of 50 cm. Large proportion of small landed fish were observed in vessels fishing with beach seine, this was due to illegal nature of the beach seine, where by fishermen used small mesh sizes of 10 mm to 12 mm. However, beach seine had higher CPUE (kg/gear/day) (44.9) and gillnet had the lowest (22.6). This study revealed that the mean length from all sites were below the legal minimum size required by the Tanzanian government, suggesting that all beaches are involves in over exploration of fish.
Assessment of effects of effective microorganisms on broiler chicken performance and malodour reduction In poultry house
(Sokoine University of Agriculture, 2011) Mgunda, Honorius Dismas
The study was conducted to assess the effects of Effective Microorganisms (EM) as feed additive in broiler chicken production on growth performance, health and foul smell control in poultry house. The experiment involved two hundred and ten, day old hybro broiler chicks which were randomly allocated to 14 pens each with 15 birds in seven treatments with two replicates. The main treatment (EM) was provided to experimental birds in two levels: 10mlEM2/l and 20mlEM2/l either in drinking water or by spraying in litter material or both in water and litter. After 42 days of the experiment 70 live chickens were selected and 5 birds/pen from each replicate were slaughtered for carcass assessment. There were significant difference between treatments on growth performance and carcass yield. EM treated groups had significant higher body weight gain, cumulative body weight gain and average daily body weight gain compared to no-EM control group. Carcass yield percent were comparatively higher in EM treated birds than control groups. T7 had significantly high carcass yield percent (79.13%) compared to other treatments and control group (73.91%). Internal organs such as gizzard and liver had significantly higher weights for EM treated birds compared with no-EM control birds. The overall mortality rate of birds was 12.8% and the highest mortality rate occurred in the first week (9%) and in the second week (3.3%), due to sudden death syndrome, salmonellosis, and huddling. Significant differences were also observed between treatment effects and treatment combinations on ammonia concentration. Pens with birds receiving 20mlEM/l both in water and litter had significant low ammonia levels compared with control group. It is concluded that EM had growth promoting effects, reduced mortality rates and reduced significantly the ammonia levels in poultry house in higher dose of 20mlsEM2/l concurrently supplemented in water and sprayed in litter.
Assessment of factors affecting performance of dairy cattle kept in smallholder farms in peri-urban areas of Temeke municipality
(Sokoine University of Agriculture, 2013) Chaussa, Karume Semfuko
There was a lack of detailed information of factors affecting the performance of dairy cattle kept in smallholder farms in Temeke municipal. Two approaches were employed to identify factors that affect the productivity and reproductive performance of dairy cattle kept in the study area. The first approach used structured questionnaire which were administered to 84 dairy farmers using a cross sectional survey technique to collect data from 12 villages. The second approach was a longitudinal monitoring where 16 lactating dairy cattle from four streets owned by dairy farmers that filled the questionnaire were monitored for thirty days where feed intakes and milk yield were measured and recorded. Feed samples were collected for quality evaluation. The daily milk yield of lactating cows under cross sectional survey and longitudinal monitoring was 8 litres with range of 4- 13 litres and 9 litres with range of 5-13 litres per cow per day, respectively. The major limitations to improved production identified by farmers were diseases and erratic extension services. The overall percentage of crude protein (CP), calcium (Ca), Phosphorus (P), In vitro dry matter digestibility (IVDMD) and Metabolisable energy (ME) contents of mixed forages fed to the animals were 6.38, 0.2, 0.17, 44.77 and 7.14, respectively. IVDMD and ME contents of mixed forages fed to cattle in Mbutu village were significantly (P<0.05) higher than those from Kizani, Kidagaa and Kwachale villages. The overall daily nutrient intakes of ME, CP, Ca and P for a cow weighing 420kgs in the study area were 87.5, 758g, 22.9g, and 18.5g per cow per day, respectively which did not meet the requirement for the production of 12 litres of milk per day. According to NRC (2001) a cow weighing 420kg requires 108 ME, 1357gCP, 46.2gCa and 34gP. Therefore supplementary ration of 20.5ME, 599gCP, 23.3g Ca, and 15.5gP per day will be required to cover the shortfall of 3 litres of milk per day.
Assessment of farmers perceptions on the status of astripomoea hyscamoides (Kongwa weed) invasiveness in central Tanzania
(ournal of Plant Sciences and Agricultural Research, 2018) Nkombe, Boniphace; Sangeda, Anthony; Sibuga, Kallunde; Hermansen, ohn
nterference of land use by weeds particularly in grazing and crop lands has increasingly reduced the agriculture productivity. In this article, we assess farmers’ and other key stakeholders’ perception on the status of A. hyscamoides invasiveness in terms of effects and possible control approaches. A combination of three Focused Group Discussions, interviews with 10 key informants and 90 household through systematic random sampling techniques were used to collect data on farmer’s perception about the weed effects and possible control measures. Results indicated that the weed cover has increased for the past 5 years. The majority of the farmers (75%) agree that the weed has negative effects while 25% of the farmers considered it to have both positive and negative consequences- the positive impact related to the fact that the weed can serve as feed. Similarly farmers were also aware of the source of spread which includes animals such as cattle and high rainfall. On the other hand, findings revealed little initiative toward control of the weed. However, farmers were positive to contribute towards the control of the weed through sustainable land management strategies or integrated weed management approaches, if relevant technical assistance is offered. In addition, there is a need of baseline data for monitoring the direction of spread and abundance in order to strategically control further invasions and select appropriate management options in the already affected areas.
Assessment of feeding practices and performance of dairy cattle in Kibaha district, Tanzania
(Sokoine University of Agriculture, 2009) Dawson, N. D.
Two studies were carried out in Kibaha District to investigate feeding practices and performance of dairy cattle kept by smallholder farmers. In experiment 1, formal survey which aimed at assessing the existing feeding practices, performance and constraints, involved 30 dairy farmers from 3 wards. In experiment 2, twenty four (24) lactating cows from two wards, that is 12 cows from each ward, were monitored for one month where intakes and milk yield were measured. In experiment 1; the performance in terms of reproduction and milk yield of cows under both zero and full grazing, was low during wet and dry seasons. Major constraints identified were nutritional related causes by the existing feeding practices. In experiment 2, the overall percentages of crude protein (CP), in vitro dry matter digestibility (IVDMD), neutral detergent fibre (NDF), calcium (Ca), Phosphorus (P) and overall means of Metabolizable energy (ME MJ) contents of mixed forages under full grazing were 6.18, 48.01, 73.58, 0.25, 0.16 and 6.88, while those under zero grazing were 6.09, 49.08, 74.2, 0.24, 0.18 and 7.02, respectively. The overall daily nutrient intakes (g/ kgW0.75) of zero grazed cows were 120, 7.48, 0.26, 0.21 and 0.86 MJ for DM, CP, Ca, P and ME respectively. The daily milk yield of lactating cows under full grazing and zero grazing systems measured during monitoring experiment were 5.45 and 6.59 l/cow, respectively. Production performance of dairy cattle observed during wet season was suboptimal, probably due to underfeeding attributed by lack of adequate supplementation. It is, therefore proposed to supplement the animals with concentrate that will supply 41.6 MJ, 1012g CP, 38g Ca, and 22g P per cow/ day for optimal milk production.
Assessment of feeding practices and performance of dairy cattle in Kibaha district, Tanzania
(Sokoine University Of Agriculture, 2009) Dawson, Nkenwa Darlington
Two studies were carried out in Kibaha District to investigate feeding practices and performance of dairy cattle kept by smallholder farmers. In experiment 1, formal survey which aimed at assessing the existing feeding practices, performance and constraints, involved 30 dairy farmers from 3 wards. In experiment 2, twenty four (24) lactating cows from two wards, that is 12 cows from each ward, were monitored for one month where intakes and milk yield were measured. In experiment 1; the performance in terms of reproduction and milk yield of cows under both zero and full grazing, was low during wet and dry seasons. Major constraints identified were nutritional related causes by the existing feeding practices. In experiment 2, the overall percentages of crude protein (CP), in vitro dry matter digestibility (IVDMD), neutral detergent fibre (NDF), calcium (Ca), Phosphorus (P) and overall means of Metabolizable energy (ME MJ) contents of mixed forages under full grazing were 6.18, 48.01, 73.58, 0.25, 0.16 and 6.88, while those under zero grazing were 6.09, 49.08, 74.2, 0.24, 0.18 and 7.02, respectively. The overall daily nutrient intakes (g/ kgW0.75) of zero grazed cows were 120, 7.48, 0.26, 0.21 and 0.86 MJ for DM, CP, Ca, P and ME respectively. The daily milk yield of lactating cows under full grazing and zero grazing systems measured during monitoring experiment were 5.45 and 6.59 l/cow, respectively. Production performance of dairy cattle observed during wet season was suboptimal, probably due to underfeeding attributed by lack of adequate supplementation. It is, therefore proposed to supplement the animals with concentrate that will supply 41.6 MJ, 1012g CP, 38g Ca, and 22g P per cow/ day for optimal milk production.
Assessment of genetic diversity and population trend of frigate tuna (auxis thazard) in Tanzania marine waters
(Sokoine University of Agriculture, 2022) Maduhu, Elizabeth Mayunga
Frigate tuna (Auxis thazard) is one of the most harvested marine fish in Tanzania and contributes to food security of the people living in the coastal areas and the country’s economy in general. Frigate tuna is highly exploited due to its better meat property and there is a danger that, in a long run it will be depleted. Therefore, there is a need to establish strategies for sustainable utilization and conservation of the overexploited tuna species. Establishment of conservation strategies requires information on genetic diversity and the distinctiveness of the species. Furthermore, effective management of frigate tuna requires information about population size and dynamics. This study assessed the stock genetic diversity and structure of frigate tuna (Auxis thazard) populations using mitochondrial displacement loop (mtDNA D-loop) sequences. Furthermore, the study assessed population trends in Tanzanian marine waters using secondary data obtained from the Ministry of Livestock and Fisheries and collected for a five-year period from 2015 to 2019. Also, the size of frigate tuna caught in Tanzania’s marine waters was determined. For the genetic diversity study, a total of 100 frigate tuna were collected from small-scale fishermen at Dar es Salaam (20 fish), Tanga (30 fish), Mtwara (30 fish) and Zanzibar (20 fish) landing sites. For each fish, a muscle tissue sample (approximately 50 g) was collected from the area above the lateral line of the fish and near the dorsal fin and put in a vial containing 95% ethanol, and the vial was labelled. DNA extraction was done using a genomic DNA mini-extraction kit (Quick-DNA Kit). DNA quantification was done by using a spectrophotometer. The DNA concentration was adjusted to 50 ng and then stored at 4 o C. The DNA samples were sent to the Agricultural Research Council-Biotechnology Platform, South Africa for polymerase chain reaction (PCR) amplification and sequencing. A fragment of 432 bp containing the first half of the mitochondrial DNA control region (D- loop) was amplified using the following primer set. The forward primer sequence was 5′- CCGGACGTCGGAGGTTAAAAT-3′ and reverse primer sequence was 5′- AGGAACCAAATGCCAGGAATA-3′. Sequencing of the purified PCR fragments was performed using the same primers. The sequencing was done using an ABI PRISIMTM 3100 Genetic Analyzer (Applied Biosystems). A total of 88 haplotypes were identified in the four populations. Hyplotype diversity was high in all populations. The haplotype diversity of Mtwara and Zanzibar populations were the highest (1.000 ± 0.010) while the Dar es-Salaam and Tanga populations had the lowest haplotype diversity of 0.993 ± 0.021 and 0.992 ± 0.012, respectively. The Tanga population had the highest nucleotide diversity (0.078 ± 0.018), followed by Zanzibar (0.027 ± 0.014), Mtwara (0.025 ± 0.014) and Dar es Salaam populations (0.016 ± 0.009). Results from AMOVA indicated that variation within the populations was higher (90.35%) than the variation among populations (9.64%). According to the results for F ST , genetic differentiation between populations was greatest between Tanga and Dar es Salaam (0.17828), followed by Tanga and Zanzibar (0.14633) and Tanga and Mtwara populations (0.13865). The genetic distance between the Dar es Salaam population and the Tanga population was the highest (0.01001), followed by the genetic distance between Tanga and Zanzibar populations (0.00873) and Tanga and Mtwara (0.00827), while the genetic distance between Mtwara and Zanzibar was the lowest (0.0004). The results for the rate of migration among the populations showed high gene flow as revealed by the number of immigrants per generation. Gene flow between Mtwara and Zanzibar populations showed the highest number of immigrants (Nm = 18.31), followed by Dar es Salaam and Zanzibar populations (Nm = 15.83), while the lowest number of immigrants was found between Tanga and Dar es Salaam populations (Nm = 1.18), between Tanga and Zanzibar populations (Nm = 1.47) and between Tanga and Mtwara (Nm = 1.55). The phylogenetic tree reconstructed based on the 88 haplotypes grouped the haplotypes into two major clusters. Cluster 1 consisted of nine haplotypes, of which eight were solely from the Tanga population and one from reference sequences of Euthynnus affinis (Kawakawa tuna). Cluster 2 included haplotypes from Dar es Salaam, Mtwara, Tanga, and Zanzibar populations. There were no population-specific sub-clusters. Population history was assessed using Fu’s Fs and Tajima’s D, and the results indicated negative values. Population expansion of A. thazard was suggested based on the results of neutrality tests. In the second study, data from 4906 tons of frigate tuna were obtained from the Ministry of Livestock and Fisheries and used to assess the population trend in the four localities for the period from 2015 to 2019. The data were further subjected to ANOVA to test the significance of the difference in catches among years and locations. Over a five-year period, a total of eight species of tuna, namely Auxis thazard, Euthynus affins, Istiompax indica, Rachcentron canadum, Rastrelliger kanagurta, Scomberomorus plurilineatus, Thunnus obesus, and Xiphias gladius, were caught in the study locations. The quantity of catch differed among species (p = 0.001), whereby Rastrelliger kanagurta was the most caught species (13,473 tons for the period of five years), followed by Scomberomorus plurilineatus (7,489 tons for five years). In the case of A. thazard, the average mean catch over a five-year period was 981.16 t, contributing 19.99% of the total tuna species caught. The catch was higher in 2015 than in any other year afterward in all localities. A total of 240 frigate tuna (48 fish from each site) were collected from fishermen and measured for total body length (in cm) and body weight (in g) to assess the size of fish caught. The total length ranged from 36 to 38.0 cm, while the body weight ranged from 461 to 1612 g. The fish from Mtwara had the smallest mean body weight (792.284 ± 33.092 g) while those from Dar es Salaam had the largest mean weight (977.692 ± 25.841 g). It is concluded that there is high within population genetic diversity, but the genetic differentiation of frigate tuna populations is not significant among the four sites, hence, they can be regarded as a single stock unit for management purposes. Also, the production trend of A. thazard showed a decreasing trend over the five year period from 2015 to 2019 and the relationship between body length and weight was linear and positive. The length and weight of A. thazard exhibited isometric growth by which fish grow in weight as length increases, and the condition factors were > 1 in all sampling sites. The condition factor greater or equal to one is good, indicating a good level of feeding, and proper environmental condition.
Assessment of genetic purity and diversity of farmed tilapia fish in Tanzania mainland
(Sokoine University of Agriculture, 2021) Shabani, Mashaka
Fish farming in Tanzania is done in ponds and cages by commercial and smallholder farmers, mostly using tilapia species. The productivity of fish farming is believed to be strongly influenced by the quality of the strain cultured. In Tanzania tilapia culture is mainly dominated by Oreochromis and Coptodon spp, and most authorities consider the fast-growing Oreochromis niloticus to be the most appropriate species for aquaculture in various parts of the country. However, there other species that are farmed in some areas such as Oreochromis urolepis and Oreochromis leucostictus. These species are known to hybridise with Oreochromis niloticus. This study assessed the purity and genetic diversity of tilapia fish in hatcheries and farms in Tanzania Mainland. The study focused on three specific objectives which were; i) assessment of sources of tilapia broodstocks and fingerlings in hatcheries and farms, ii) identification of farmed tilapia fish species and hybrids using single nucleotide polymorphism (SNPs) and iii) assessment of within-and between-population genetic diversity of Nile tilapia broodstock in hatcheries and farms. Information on the sources of tilapia broodstock and fingerlings in hatcheries and farms in Tanzania Mainland was collected through face-to-face interview using structured questionnaires. A total of 248 and 16 respondents from fish farms and hatcheries, respectively, were interviewed. Data on sources of tilapia broodstock and fingerlings were analyzed using Statistical Package for Social Sciences (SPSS.Version, 21) to derive descriptive and inferential statistics. Significant differences were judged at a probability level of p ≤ 0.05. Tilapia species and hybrids cultured in hatcheries and farms were determined through SNP analysis. Species identification was facilitated by inclusion of reference samples of Oreochromis niloticus and O. leucostictus from Lake Albert in Uganda and O. urolepis from the lower Wami River in Tanzania in the analysis. A total of 536 tilapia pectoral fin samples were collected from 10 fish hatcheries and 59 fish farms3 located in seven agro-ecological zones of Tanzania Mainland. Following euthanasia, clips of the pectoral fin were cut and placed into labelled vials containing 95% ethanol. The vials were put in a cool box packed with ice and transported to a laboratory where they were stored at -20 o C, until DNA extraction. Overall, analysis was carried out on 190 fin clips, which were selected from the initial collection of 536 tilapia specimens. DNA extraction from fin clips was done using the BioArk extraction kit and SNP genotyping was performed by LGC Genomics GmbH campany in Berlin. The SNP assay was originally calibrated with three species of Oreochromis (O. niloticus, O. urolepis and O. leucostictus), not with Coptodon. A pseudo-reference set for Coptodon was generated using four specimens for which clear photographs of Coptodon were available. These were then coded as reference samples and used to identify the genotypic profile of Coptodons in the analysis, in an attempt to identify Coptodon specimens among the non- photographed samples. Principal component analysis (PCA) was done using SNPRelate package in R v4.01 software and used to preliminary identify the species and hybrids present in the collected tilapia samples. Ancestry analysis was done using Admixture v1.3.0 software to determine the proportion of ancestral admixture for assigning appropriately the different types of species and their hybrid present in both fish hatcheries and farms. A threshold of 80% cluster membership was used to classify samples as pure species. Individuals with cluster membership of less than 80% were considered to be potential hybrids. Based on cluster membership criterion, a total of 50 O. niloticus were identified out of 190 genotyped samples, whereby 31 and 19 O. niloticus individuals were from fish hatcheries and farms, respectively. These were then selected as samples for the study of assessment of within and between population genetic diversity of Nile tilapia broodstocks in hatcheries and farms. The population structure of the fish samples was analyzed using Structure v.2.3.4 Software with K values ranging from 2 to 5. Markov4 Chain Monte Carlo (MCMC) of 100 000 iterations with a burn-in period of 10 000 was carried out for each K value. Observed (Ho) and expected (He) heterozygosity parameters were used to assess the within population genetic diversity for the hatchery populations. Similarly average individual inbreeding coefficient (F IS ) for O. niloticus identified in fish hatcheries were estimated using stacks v2 software. The R package StAMPP was used to perform Analysis of Molecular Variance (AMOVA) using 1 000 permutations. Also, the principal component analysis (PCA) was carried out using the R package Adegenet version 2.1.1. The results on sources of tilapia fingerlings and broodstock indicate that, the main sources of tilapia broodstocks in fish hatcheries were other hatcheries within the country (45.5%). However, some fish hatchery managers (12.3%) were importing broodstock from Uganda and Thailand. The results revealed that fish hatcheries and natural water bodies were used as sources of fingerlings in all agro-ecological zones, but the extent of utilization differed significantly among the agro-ecological zones. Fingerlings from the wild were more utilized in the Northern, Western and Lake Zones while the use of fingerlings from hatcheries predominated in the Eastern zone. The results on tilapia fish species and hybrid identification in fish farms and hatcheries, indicate that 91.52% of the fish farms and 70% of the hatcheries were not culturing pure O. niloticus, but hybrids or tilapia of other species. The pure O. niloticus (percentage of pure individuals in brackets) were observed at Ruvu fish farm (12.90%), Safina bigfish (12.90%) and 821KJ-Bulamba (51.61%). Likewise the results for within and between population genetic diversity of Nile tilapia broodstocks in hatcheries and farms indicated that pairwise F ST values varied from 0.072 to 0.359 in some of fish hatcheries. The lowest F ST values were found between 821KJ- Bulamba and populations from Mwamapuli, Ruvu fish farm, and Safina bigfish. The highest F ST values were observed between 821KJ-Bulamba and Faiza fish farm. Admixture was detected at Mwamapuli, Faiza fish farm, Ruvu fish farm and Safina5 bigfish, but was not detected at 821KJ-Bulamba. In fish farms admixture was detected at SUA-Morogoro and Babati populations. Result on Analysis of molecular variance (AMOVA) show that 17.71% of genetic variation was found among populations, -7.69% among individuals within populations and 89.98% of variation was within individuals. Principal component analysis indicated one genetic group of O. niloticus clustering to O. niloticus reference with no any individual clustering with either O. urolepsi reference or O. leucostictus reference. This study concluded that, the main sources of tilapia broodstock for fingerlings production in hatcheries are other hatcheries within and outside Tanzania as well as wild sources. The main sources of tilapia fingerlings for stocking fish farms in Tanzania mainland are hatcheries within Tanzania, wild sources and recruits from other fish farms. A large number of sampled fish farms (91.52%) and hatcheries (70%) do not culture pure Oreochromis niloticus, instead they culture hybrids and a mixture of either Oreochromis niloticus with other species of tilapia or unknown tilapia species. There is high number of hybrid individuals both in fish farms and hatcheries than any pure single species. The high level of genetic impurity in farmed tilapia fish in both hatcheries and farms is contributed by existence of O. leucostictus, O. jipe, and O. urolepsi and Coptodon species. There is high genetic diversity within populations than among Nile tilapia populations. Based on the findings of this study it is recommended to establish certified hatcheries in each agro-ecological zone to increase accessibility of quality seeds. Also it is recommended to establish a practical tilapia breeding program for maintaining the purity of different tilapia strains as well as conducting regular training to fish farmers and hatchery managers on how to handle and manage tilapia broodstock.
Assessment of genetic variation among four populations of Small East African goats using microsatellite markers
(South African Society for Animal Science, 2017) Nguluma, A. S.; Zhao, Y.; Huang, Y.; Chen, L.; Msalya, G.; Lyimo, C.; Guangxin, E.; Chenyambuga, S. W.
The majority of goats in Tanzania belong to the Small East African (SEA) breed, which exhibits large phenotypic variation. This study aimed to determine the genetic structure of, and relationships among four populations (Sukuma, Gogo, Sonjo, and Pare) of the SEA breed that have not been studied adequately. A total of 120 individuals (24 from each population) were analysed at eight microsatellite loci. In addition, 24 goats of the South African Boer breed were used as reference. Observed heterozygosity (Ho) ranged from 0.583 ± 0.04 for Sukuma to 0.659 ± 0.030 for Gogo, while expected heterozygosity (He) ranged from 0.632 ± 0.16 for Sukuma to 0.716 ± 0.16 for Boer. Five loci deviated from Hardy–Weinberg equilibrium (HWE) across populations. The mean number of alleles ranged from 4.75 ± 1.58 for Pare to 6.88 ± 3.00 for Sukuma. The mean inbreeding coefficient (F IS ) ranged from 0.003 in Sonjo to 0.148 in Sukuma. The differentiation coefficient (F ST ) was highest (0.085) between Boer and Sukuma and lowest (0.008) between Gogo and Sonjo. The largest genetic distance (0.456) was found between Sukuma and Boer, while the smallest (0.031) was between Gogo and Sonjo populations. Pare, Gogo, and Sonjo populations, formed one cluster, while Sukuma and Boer populations formed two separate clusters. From the findings, it can be concluded that the SEA goats in this study showed high in population genetic variation, which implies that there is good scope for their further improvement through selection within populations. The Sukuma population, which has fairly high inbreeding, is moderately differentiated from Pare, Sonjo, and Gogo goat populations, which showed a high level of admixture. Conservation and improvement strategies of the goats should be designed with first priority being on Sukuma goats. ____________________________________________________________________________________
Assessment of growth and population structure revealed sufficient genetic diversity among lambs of Mecheri sheep in Tamil Nadu, India
(Elsevier, 2022-07) Thiruvenkadan, Aranganoor Kannan; Muralidharan, Jaganathan; Ramanujam, Rajendran; Msalya, George Mutani
This study was designed to evaluate various genetic parameters for growth characteristics, genetic progression, and to find out the genetic constitution of a population of Mecheri sheep, a tropical breed native to Tamil Nadu, southern India. Data for this study were various records from 2768 lambs, which were a result of mating of 110 sires and 748 dams during a period of 10 years, between 2010 and 2019. Among the evaluated traits included body weights at various stages of growth such as birth weight (BWT), as well as weight at weaning (WWT), at 6- months (6WT), at 9-months (9WT), and at one-year-old (12WT). Estimated genetic parameters included additive direct and maternal heritabilities and genetic correlations, genetic changes, inbreeding, and generation interval. Among the software required for various analyses were the ENDOG (version 4.8) and Restricted Maximum Likelihood (REML). Mean ( ± SE) values of weight at birth and at 12 months were 2.37 ± 0.02 and 21.34 ± 0.34 kg respectively. Direct heritability values estimated at birth, six months, as well as 12 months were respectively 0.14 ± 0.05, 0.07 ± 0.03, and 0.08 ± 0.03. Maternal heritability value for BWT was 0.28 and whereas low and varied values between 0.03 and 0.05 were obtained for both weaning and post-weaning traits. Overall, genetic improvement was low at birth (− 0.0025 kg) and highest (0.1314 kg) around weaning age. Average inbreeding coefficient value was 0.16 % and the effective population size of founders was 100.35, while mean generation interval ( ± SE) was 3.44 ± 1.15 years. Effective number of founders was 18.01 % and indicates that Mecheri sheep have their origin from a moderate genetic base. The observed f e /f a ratio was 1.00 and is linked to presence of sufficient founding ancestors, less bottlenecks, and possibly implementation of rotational mating scheme at the farms. In summary, our study revealed that there are high correlations between WWT and post-weaning weights. Based on heritability values, the WWT could be used as an important trait which can facilitate improvement in body weight of Mecheri lambs. Further, the present genetic parameter values for different variables advocates that the genetic progress for body weight at various stages of growth is feasible in Mecheri sheep thorough genetic selection strategies. We conclude that sufficient genetic diversity is maintained within Mecheri sheep.
Assessment of improvement of chemically and biologically treated maize stover and subsquent utilization of treated materials for beef production
(Sokoine University of Agriculture, 2016) Mushi, P. V.
Two studies were conducted to evaluate effectiveness of CaO, enzymes, microbes and Ca(OH)2 in improving the feeding value of maize stover (MS) for beef animals. Study I involved five treatments; untreated MS (T1), CaO treated MS (T2), CaO + enzymes treated MS (T3), CaO + microbes treated MS (T4), CaO + enzymes + microbes treated MS (T5). Study II involved untreated MS (T6) and MS treated with Ca (OH)2 (T7). The treatments were evaluated for chemical composition, degradability, gas production, digestibility and animal performance. Differently treated MS were fed to 80 steers and 32 steers in study I and II respectively. There was increase in CP, CF, ash and calcium while NDF was reduced in treated MS. Disappearance values at 48hrs ranged 40 to 51% units for dry matter (DM) and 40 to 47% units for organic matter (OM). The `a’ values for DM and OM degradability were 3.17% and 9.44%, 1.02% and 4.71% in untreated and treated MS respectively while the `c’ value was 0.012%/h and 0.02%/h, for treated and for untreated MS. Gas production values at 24hrs ranged 22 to 35 ml/g DM. The `b’ values were 36.2% in untreated and 42.54% for treated MS. T3 had the highest In vitro organic matter digestibility (OMD) (55%) while T5 had the lowest (48.2%). T1 had the highest Metabolizable Energy (ME) (7.2 MJ/kg DM) while T4 had lowest (5 MJ/kg DM). Dry matter intake, final body weight and average daily gain were higher for T1 and T6 than T2, T3, T4, T5 and T7. The steers on T7 had higher DM digestibility (70.2%) than those on T6 (55.7%). It is concluded that the lime treatment was effective in solubilizing the cell wall constituents and improve the digestibility of MS but had a negative effect on intake and body weight gain.