Utilization of cassava roots afflicted by cassava brown streak disease ln broiler rations
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Date
2016
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Publisher
Sokoine University of Agriculture
Abstract
Cassava roots afflicted with Cassava Brown Streak Disease (CBSD) were used in a study
involving 600 Hubbard broiler chicks to evaluate its utility as a substitute for maize meal
in broiler rations.
The chicks were allocated to three dietary treatments each with 60
birds in a complete randomized design. The CBSD cassava roots were ranked in to three
classes (CLI, CL2 and CL3) based on severity of roots necrosis. Three diets were
formulated to maintain ME content at between 12-12.55MJ/kgDM and CP around 18-
20% in which CBSD replaced maize at 25%, 50% and 75%. Average voluntary feed
intake per bird for CL1 at 25,50 and 75% inclusions were respectively 130.31±8.46,
110.86i3.32, 108.76i5.01; the corresponding intakes for CL 2 were
104.33i2.20,
105.10±7.02, 105.3H4.42 ; and for CL3 were 90.06il4.71, 90.06il4.71, 103.10i4.90.
At 50% and 75 % levels of inclusions intakes were significantly lower (P<0.05) than that
of the Control diet (128.23i6.53) regardless of class of root damage. The Average Daily
Gain (ADG) per bird for CL1 at 25, 50 and 75% inclusion were respectively 30.48i 1.84,
27.57i0.62, and 27.35i0.94; for CL2 were 25.75il.57, 26.15i2.58, 24.98i0.84; and for
CL3 were 22.17i2.11, 23.11i2.87, 24.29il.84. While for control diet is 30.62il.59.
Cooking losses in breast were 19.03il.77, 16.95il.79, 17.29il.48 respectively CL1, C12
and CL3 at 25% level; 21.17il.74, 17.02il.66, 17.78il.81; for 50% level; 23.67il.46,
19.10i0.37, 20.29il.27 for 75% and 19.53il.58 for the control. Roots damage had no
effect on cooking loss. At 25% inclusion level feed cost were lower and the gross margin
higher than for the Control diet while ADG gain were similar .It is concluded that CBSD
afflicted cassava can be used to replace Maize meal up to 25% inclusion level.
Description
Dissertation
Keywords
Cassava roots, Cassava Brown, Streak Disease, Hubbard broiler chicks, Maize meal, Broiler rations