Effect of rate of inclusion of fishmeal prepared by cooking and sun drying of fish offal on feed intake and nutrient retention of growing Rhode Island Red chicks

Abstract

Effect of cooked and sun dried fish offal on intake and nutrient retention of growing Rhode Island Red (RIR) chicks in southern Ethiopia was evaluated. Unsexed day old RIR chicks were uniformly brooded, vaccinated against Gumboro and Newcastle diseases. At the age of 14 days, 10 chicks were assigned to each of the 5 replicates of the 6 dietary groups, fed for 11 weeks and daily group feed intakes were recorded. The control diet (T₁) consisted of Maize (34.1%), wheat short+bran (21.0%), limestone (1.20%), salt (0.5%), premix (0.1%), lysine (0.05%), methioinine (0.05%), roasted soybean (27.0%) and noug cake (16.0%); the rest of the diets contained all ingredients in the control plus fishmeal at rates of 3.32% (T₂), 6.64% (T₃), 9.96% (T₄), 13.28% (T₅), and 16.6% (T₆) of the diet and had 19.76, 18.89, 19.82, 18.44, 18.96 and 19.20% cp, respectively. At the beginning of the feeding trial, 13 chicks representing initial body weight of those in the trial were stunned by dislocation of the neck. At the end, one male and one female chick from each of the 3 replicates of each of the 6 treatment groups were systematically selected, tagged, fasted for 12 hours, weighed, and stunned by dislocation of the neck. All carcasses were kept intact in deep freezer at -20°C and then cut into small pieces in freezing condition, minced and dried in an oven at 65°C for 80 hours, ground, homogenized and chemically analyzed. Chicks fed T₁ had significantly (p<0.001) lowest (68.5g dm, 13.3g cp, 0.54g Ca, 0.35g P and 231kcal me head^-1) but those on T₆ had the highest daily nutrient intakes (77 g dm, 14.8 g cp, 1.81 g Ca, 0.58 g P and 243 kcal ME head^-1). T₁ (2.28) of all and T₄ (2.65) among fishmeal groups viz T₂ (3.01), T₃ (2.92), T₅ (2.86) and T₆ (2.85) had the lowest (p<0.001) cp retention (CPR). Males had significantly (p<0.001) higher CPR (2.9 g head^-1d^-1) than female (2.62 g head^-1d^-1). Energy retention of T₁, T₂, T₃, T₄, T₅, T₆ were 21.6, 28.7, 29.1, 27.0, 25.9 and 28.1 kcal head^-1d^-1, respectively, with significant differences (p<0.01) only between T₁ and fishmeal groups. Sex had no influence on energy retention. Based on the results of the present study fishmeal can be incorporated up to 16.6% of the diet of rir chicks, however, best results of protein retention was obtained at 3.32%, and of energy retention at 6.64%.