Browsing by Author "Chenyambuga, S. W."

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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. ____________________________________________________________________________________
Effect of different dietary protein sources on fingerling production in Nile Tilapia (Oreochromis niloticus)
(International Journal of Fisheries and Aquatic Studies, 2019-02-04) Mnyoro, M. S.; Chenyambuga, S. W.
Availability of quality and reliable feeds is one of the main challenges facing aquaculture development. A 12 week experiment was set where, broodstock of Nile tilapia were fed various diets with different plant protein sources for 8 weeks. The produced fingerlings were fed a common diet thereafter for 4 weeks. The diets contained Fish meal, maize meal and minerals; Moringa leaf meal, maize meal and minerals; Sunflower seedcake, maize meal and minerals; Moringa leaf meal, sunflower seedcake, maize meal and minerals. All other factors including water quality parameters were constant in all experimental units. It was noticed that, fish brood stock fed diets 1 and 2 produced highest numbers of fish fingerlings, but fish fingerlings produced by brood stock fed diet 2 showed the greatest growth and survival. This study therefore recommends diet 2 (Moringa leaf meal, maize meal and minerals) for broodstock feeding. The ingredients are readily available for use in aquaculture production.
The estimate of genetic correlation and heritability of various traits in small East African goats
(Tanzania Journal of Agricultural Sciences, 2002) Malole, J. I.; Kifaro, G. C.; Mtenga, L. A.; Chenyambuga, S. W.
This study was done on three strains of East African goats namely, Dodoma. Kigoma and Mtwara with the aim of estimating heritability for pre-weaning (4 months), post-weaning (8 months) and yearling (12 months) growth rates. Other heritability parameters measured were for weight at birth, 4, 8, and 12 months of age and helminth resistance traits (faecal egg count or FEC and packed cell volume or PCV) at six and twelve months of age. Genetic correlations were also determined between FEC. PCV and growth rate at six and twelve months of age. Genetic correlation and heritability were estimated using the Restricted Maximum likelihood (RFML) of the variance component (Var Comp) procedure of the Statistical Analysis System (SAS) package. Most of the traits were observed to have moderate heritability ranging from 0.32 to 0.39, with exception of weight at weaning (4 months). 8 months, one year of age and PCV, which had high heritability (0.4-0. 44) estimates. Negative genetic correlations were observed between FEC and growth rate at six months (rg = -0.69 ± 0.042), and twelve months of age (rg = -0.8 ± 0.011), whereas, PCV-showed positive genetic correlations with growth rate within the same periods rg = 0.59± 0.010 and rg = 0.45 ± 0.022, respectively. It was concluded that the moderate and high heritabilities obtained for growth rates, weights at different age FEC in this study indicate that improvement of growth rate, body size and genetic resistance to helminthosis could be improved through selection and manipulation of both the additive genetic action and non genetic (ienvironmental) components for tropical goat improvement. It was also recommended that genetic manipulation at molecular level should be employed in identifying and isolating quantitative and qualitative trait loci (QTL) linked to economic and desirable traits which will enable development of goats suitable for different ecological zones.
Genetic characterization of indigenous goats of sub-saharan africa using microsatellite DNA markers
(Asian-Australasian Journal of Animal Sciences, 2004) Chenyambuga, S. W.; Hanotte, O; Hirbo, J; Watts, P. C; Kemp, S. J; Kifaro, G. C.; Gwakisa, P. S; Petersen, P. H; Rege, J. E. O
Genetic diversity of sub-Saharan African goats was assessed using 19 microsatellite markers. Breeds were sampled from eastern Africa (Maasai, Kigezi, Mubende, North West Highland, Arsi-Bale), southern Africa (Ndebele, Pafuri) and West Africa (West African Dwarf, Maure, Djallonke). European breeds (Grisons Striped, Toggenburg), Asian breeds (Mongolian Cashmere, Bandipur) and a Middle East breed (Arab) were also included. The mean number of alleles per locus and average gene diversity ranged from 5.26±0.464 (Djallonke) to 7.05±0.516 (Mubende) and from 0.542±0.036 (Pafuri) to 0.672±0.031 (Ndebele), respectively. The between breeds variation evaluated using G ST and θ were found to account for 14.6% (θ) and 15.7% (G ST ) of the total genetic variation. The D A measure of genetic distance between pairs of breeds indicated that the largest genetic distance was between Pafuri and Djallonke while the lowest genetic distance was between Arsi-Bale and North West Highland. A neighbour-joining tree of breed relationships revealed that the breeds were grouped according to their geographic origins. Principal component analysis supported the grouping of the breeds according to their geographic origins. It was concluded that the relationships of sub-Saharan African goat breeds were according to their geographical locations implying that the goats of eastern Africa, West Africa and southern Africa are genetically distinct. Within each sub-region, goat populations could be differentiated according to morphological characteristics. (Asian-Aust. J. Anim. Sci. 2004. Vol 17, No. 4 : 445-452)
Influence of sex, age and body condition score on carcass composition and tissue distribution in marketed small East African goats
(2002) Mushi, D. E.; Mtenga, L. A.; Kifaro, G. C.; Chenyambuga, S. W.
Twenty-four half carcasses of small East African goats (8 females 8 entire males and 8 castrated males) were jointed into seven joints namely: hind leg, chump, loin, rib, breast, neck and fore leg. These joints were further dissected into the separable components: muscle, bone and fat. The carcasses of these goats, were composed of 7.8, 16. 5% fat, 55.6-62, 7% muscle and 27.9- 29,5% bone. The proportions of muscle in carcasses of females (56%) and castrates (58%) were significantly (P<0.05) lower than in entire males, (63%). Fat content in the carcasses of females (16%) and castrates (12%) were signtficantly (P<0.05) higher than in entire males (9%). The neck of entire males had higher (P<0.001) percentage muscle weight (11%) than the neck of females (8%) and castrates (9%). The hind leg females had higher (P<0.05) percentage muscle weight (28%) than hind leg of males (25%) but castrates had values in between the two (27%). The fore leg off females had the least (P<0.001) percentage of muscle (21 %) compared wiith males (23%) and castrates (24%). The loin and fore legs of females had higher (17% vs. 12%) and lower (16% vs 20%), percentage of fat than those of castrates and entire males. The fore leg of females had lower (10% vs 12%) percentage of bone than that of entire males and castrates. The neck and fore leg of goats above 3 years old had higher (10% vs 9%) and lower, (22 vs 23%) percentage of muscles respectively than those of goats aged 2 to 3 years. The loin and hind legs of goats with body condition score of 4 had higher (12% vs 11%) and lower (25% vs 27%) muslce percentage respectively than those of goats with five score. The rib joint of goats with body condition score of 4 had higher (13% vs 11%) percentage of bone than those of goats with five score It is concluded that sex of the animal affects both the proportion and distribution of carcass tissue to a greater extent than age and body condition score. This means that where carcass quality is a major goal given the right market guidelines, farmer can make use of the sex differences in the proportion and distribution of carcass tissue to serve the consumer markets with meat goat of their preference.
Tick burden and acquisition of immunity to Theileria parva by Tarime cattle in comparison to Sukuma cattle under different tick control regimes in the Lake Zone of Tanzania
(2016-03) Laisser, E. L. K.; Chenyambuga, S. W.; Karimuribo, E. D.; Msalya, G.; Kipanyula, M. J.; Mwilawa, A. J.; Mdegela, R. H.; Kusiluka, L. J. M.; Gwakisa, P. S.
This study was conducted to determine tick burden and immunological parameters of resistance to East Coast fever (ECF) in Tarime and Sukuma cattle. Tick load, packed cell volume (PCV), Theileria parva (T. parva) specific antibody percent positivity (PP), and prevalence of T. parva parasites were studied in relation to dipping regime, strains, and season. A total of 50 experimental cattle were included in this study. Tick load was determined by whole body counts, antibody percent positivity was determined by the polymorphic immunodominant molecule (PIM)-based T. parva enzyme-linked immunosorbent assay (ELISA), and prevalence of T. parva parasites was detected by a nested polymerase chain reaction (PCR) based on the p104 gene. Dipping frequency on tick burden showed no statistically significant differences when cattle of either strain were dipped either once every 2 or 3 weeks in the dry and wet seasons. However, Tarime cattle had higher (p<0.05) tick count than Sukuma cattle and non dipped groups maintained high tick infestation throughout the experimental period. The PCV values were within the physiological range, although this parameter was lower in Tarime cattle (p<0.05). All cattle regardless of strain were seropositive, although Tarime cattle maintained higher PP compared to Sukuma by 15%. Conversely, the prevalence of T. parva parasites was lower in Tarime (38%) compared to Sukuma cattle (38.5%), but the difference was not significant (p>0.05). During the study period, 20% (5/25) of Sukuma cattle contracted ECF, but none of the Tarime cattle showed clinical signs for the disease. The differences between the two strains shown in terms of PP and T. parva parasite prevalence may indicate the ability of individual cattle to resist tick infestation and ECF infection under natural challenge. Higher antibody levels but lower parasite prevalence attained by Tarime cattle, suggests inherent ability of Tarime cattle to resist clinical development of ECF infection, but to remain as T. parva carriers.