Performance and body composition of finishing gilts (45 to 85 kilograms) as affected by energy intake and nutrition in earlier life: II. Protein and lipid accretion in body components.

Forty-eight commercial hybrid gilts were used to investigate the response relationships between energy intake and deposition of protein and lipid in body components of finishing pigs (45 to 85 kg) as affected by previous nutrition. Two groups of 24 gilts received a single diet either at 2.2 (restricted pigs) or 3.7 (control pigs) times maintenance (M) from 20 to 45 kg. From 45 to 85 kg, pigs from each of these two groups were fed the same diet at one of six intake levels (1.7, 2.2, 2.7, 3.2, or 3.7 x M, or adlibitum). At 85 kg, the gilts were dissected and analyzed. Protein content in the whole body decreased curvilinearly from 190 to 166 g/kg (P < .001) and lipid content increased from 116 to 210 g/kg (P < .001) with increasing energy intake. The mean content of protein was 6 g/kg higher and of lipid 29 g/kg lower (both P < .001) in previously restricted gilts. Protein (PD) and lipid deposition (LD) in the whole body, organs, lean, and fat tissue increased linearly (P < .001) with increasing energy intake. In the whole body, PD increased from 83 to 187 g/d and LD from 46 to 392 g/d. The respective response relationships in grams/day were PD = 21.8 + 3.78 x DEI and LD = -193 + 13.7 x DEI(DEI is digestible energy intake, MJ/d). The LD:PD ratio increased curvilinearly from .6 to 2.2. Previous nutrition had only small effects on PD and LD. Only PD in the organs was on average 7 g/d higher (P < .001) in previously restricted gilts. Thus, the higher protein content and the lower lipid content in previously restricted gilts was not primarily the results of compensation but was almost entirely present at the end of the restriction phase at 45 kg.