Feed intake, live mass-gain, body composition and protein deposition in pigs fed three protein levels

Author: E.H. Kemm, F.K. Siebrits, M.N. Ras and H.A. Badenhorst
Year: 1991
Issue: 3
Volume: 21
Page: 127 - 136

A group of 82 genetically lean and 90 obese Landrace pigs was allotted to three dietary treatments with lysine concentrations of 1,22 (T1), 1,02 (T2) and 0,83% (T3), corresponding concentrations of crude protein (CP) of 19,7, 16,8 and 13,7% and digestible energy (DE) concentrations of 14,4; 14,2 and 14,0 MJ/kg diet. Diets were fed ad libitum from 8 weeks of age up to slaughter for whole body chemical analyses, at ±20, ±30 or 90 kg live mass. Appropriate regression relationships were used to measure the effect of dietary protein level on the patterns of DE intake, daily gain and the deposition rates of protein (PDR) and fat (FDR) over the growth period 30-90 kg live mass. Dietary CP content had no significant effect on mean voluntary DE intakes and daily gains. DE intakes (MJ/d) for pigs from T1, T2, and T3 were 32,1; 32,2 and 32,8 respectively. Daily gains (g/d) were 737, 728 and 738 and DE : gain ratios were 43,8; 44,6 and 45,0 for the three treatments respectively. Obese pigs consumed highly significantly more DE than lean pigs (33,4 vs. 31,1 MJ/d), and also needed highly significantly more DE/kg gain (46,0 vs. 42,7 MJ), but they had similar daily gains (733 and 736 g/d). DE intake, daily gain, PDR and FDR followed curvilinear patterns. PDR curves peaked at ± 56 kg live mass (51 kg for obese gilts and 64 kg for lean boars). Deposition rates increased from a mean of 106 g/d (93 g for obese gilts and 118 g for lean boars) to 124 g (103 g for obese gilts and 143 g for lean boars) at peak deposition, only to decline thereafter to 105 g/d (85 g for obese gilts and 132 g for lean boars) at 90 kg live mass. A reduction of 15% in dietary protein content (T2) had no apparent effect on protein deposition. Pigs from T3, fed 30% less protein than pigs from Tl, deposited only 2 g (1,9%) less protein/d at 32 kg live mass, 2 g (1,6%) less at maximum deposition and 2 g (1,9%) less at 90 kg live mass.


Keywords: body composition, feed intake, growth rate, pigs., protein deposition
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