Authors : L.C. Chu, G.J. Zhang, C.J. Cai, X.B. Mao and S.Y. Qiao
Abstract: Three experiments using a total of 1140 crossbred barrows and gilts (Yorkshire x Landrace x Duroc) were conducted to determine the effects of dietary Digestible Energy (DE) density on performance and lean deposition in growing-finishing pigs during three separate phases. A completely randomized block design within sex was used involving 480 pigs in Exp. 1 (20.8-55.9 kg), 420 pigs in Exp. 2 (57.0-76.6 kg) and 240 pigs in Exp. 3 (78.6-105.8 kg) (pigs were from three different groups). Pigs were allotted to one of five treatments containing 13.62, 13.87, 14.12, 14.37 and 14.62 MJ DE kg-1. Pig body weight and feed consumption were determined every 2 weeks and carcass composition was evaluated at the start and end of the experiments. The quadratic or broken-line model was used to estimate the requirement of dietary DE concentration. In Exp. 1, there were no differences (p>0.05) in weight gain or feed efficiency. Meanwhile, carcass fat-free lean gain decreased (linear, p = 0.02; quadratic, p = 0.02) and fat-free lean index decreased quadratically (quadratic, p = 0.05) with increasing dietary energy density. The optimum dietary DE to maximize lean deposition was calculated to be 13.81 MJ DE kg-1. In Exp. 2, for pigs weighing 57.0-76.6 kg both weight gain (linear, p = 0.02) and feed efficiency (linear, p = 0.02) increased linearly with increasing DE density while carcass fat-free lean gain (p = 0.05) and fat-free lean index decreased (p<0.01). The optimum dietary DE for lean deposition was 13.76 MJ DE kg-1. In Exp. 3, the linearly decreased feed intake (linear p = 0.04) and increased weight gain (linear, p<0.01; quadratic, p = 0.01) resulted in an improvement in feed efficiency (linear, p<0.01; quadratic, p = 0.01). The quadratically decreased carcass fat-free lean gain (quadratic, p = 0.02) and decreased fat-free lean index (p<0.01) suggested that the optimum dietary DE for lean deposition was calculated to be 13.82 MJ DE kg-1.
L.C. Chu, G.J. Zhang, C.J. Cai, X.B. Mao and S.Y. Qiao, 2012. Effect of Dietary Energy Density on Performance and Lean Deposition of Growing-Finishing Pigs. Journal of Animal and Veterinary Advances, 11: 665-675.