The effect of partial substitution of plant protein by fishmeal prepared out of cooked and sun dried fish offal on feed intake and carcass traits of Rhode Island Red chicks

Abstract

Effects of cooked and sun dried fish offal, fishmeal, on intake, growth and carcass traits of Rhode Island Red (RIR) chicks was evaluated at Wolayta Soddo, southern Ethiopia. After 14 days of uniform brooding of unsexed day old RIR chicks, a feeding trial, with 6 dietary groups (T₁ to T₆), 5 replicates each and 10 chicks per replicate, was run for 11 weeks when daily group feed intakes were recorded. Results showed that chicks fed T₁ had significantly (p£ 0.01) lowest (68.5g dry matter (DM) , 13.3g crude protein (CP), 0.54g calcium (Ca), 0.35g phosphorus (P) and 231kcal metabolizable energy (ME) head^-1) but those on T₆ had the highest daily intakes (77g DM, 14.8g CP, 1.81g Ca, 0.58g P and 243kcal ME head^-1). Slaughter weight was 1022g, 1234g, 1202g, 1295g, 1272g, and 1272g head^-1 for T₁, T₂, T₃, T₄, T₅ and T₆, respectively. Commercial carcass weight (breast + thighs + drum sticks + wings + back) of the control (552g/head) was significantly (p£ 0.01) lower than fishmeal groups (683g, 671g, 729g, 717g and 711g for T₂, T₃, T₄, T₅ and T₆, respectively). Difference in weights of drum sticks, thighs, wings and back separately were significantly (p< 0.01) higher for fishmeal groups. Breast weight of T₁ (160g) was significantly (p< 0.01) lower than T₂ (196g), T₃ (203g), T₄ (219g), T₅ (213) and T₆ (217g). Total edible carcass weight, including skin, liver and gizzard of T₁ was significantly lower (676g head^-1, p£ 0.01) than the rest of the groups (837g, 807g, 874g, 860g and 850g head^-1 for T₂, T₃, T₄, T₅ and T₆, respectively). Significantly (p£ 0.05) lower Dressing % was obtained from T₁ (54.0%) than T₂ (55.3%), T₃ (55.7%), T₄ (56.2%), T₅ (56.5%) and T₆ (55.8%). Dressing percentage (on the basis of edible carcass) of T₁ (66.1%) was also significantly (p£ 0.05) lower than T₂ (67.8%), T₃ (67.1%), T₄ (67.5%), T₅ (67.6%) and T₆ (66.8%). Males had significantly (p< 0.01) higher slaughter weight (1294g) and carcass weight (721g) than females (1138g and 633g, respectively), but they had similar breast weights and dressing %. It can thus be concluded that fishmeal inclusion in to diets of growing RIR chicken up to the levels of 16.6% of the DM of the diet did not affect health or carcass traits; however, best results were obtained at 9.96%.