The amino acid requirements of pigs for maintenance and for growth

Abstract

The optimal balance of amino acids in the diet of the growing pig was estimated by ARC (1981) on the basis of a number of disparate studies augmented by data on the amino acid composition of the whole body on the premise that the amino acids incorporated into accreted body proteins are the major determinant of requirements and that this pattern is not distorted by inequalities in the utilisation of individual amino acids. In an accompanying paper (Wang & Fuller, paper no. 91) an optimal pattern was derived by direct experiment which was shown to be utilised better than that described by ARC (1981). That pattern, however, which related to one particular rate of nitrogen input and the particular rate of protein accretion which that input supported, includes two components, a requirement for maintenance and a requirement for protein accretion. There is clear evidence from studies with rats and chicks that the optimal pattern of amino acids for maintenance and growth are quite different and so the optimal pattern for any particular rate of growth will depend on the relative contributions of the two components. The purpose of this experiment was to estimate both.

The effect of the plane of nutrition on the optimum dietary amino acid pattern for growing pigs

“…The previous experiments 1989;Fuller et al, 1987 and1989) were all made with semi-synthetic diets in which casein and amino acids were the sole N sources. These were shown to be fully digested before the end of the ileum and the ideal amino acid pattern derived from those experiments referred to the pattern of absorbed rather than dietary amino acids.…”

Influence of the methionine:cysteine relationship in the feed on the performance of growing pigs

“…In the retention of amino acids, KIRCH- (1966) with adult sows, a Met: Cys relationship of 6 : 94 can be derived for the maintenance requirement (1 g N retentiodday) for S-containing amino acids. A similar relationship also appears to apply for the maintenance requirement (N equilibrium) of growing pigs (FULLER et al 1987). The higher proportion of Cys for the maintenance functions compared with the requirements for growth can be explained primarily by the keratin synthesis.…”