The tissue and dietary protein and amino acid requirements of pigs from 8.0 to 20.0 kg live weight

Abstract

Forty-three entire males were used to determine the pig's tissue requirements for protein and amino acids from 8-0 to 20-0 kg, and provide information on the capacity of diets formulated with conventional ingredients to contain the same levels and balances of amino acids as ideal protein to supply these nutrients. Seven diets with similar digestible energy (15-9 MJ digestible energy (DE) per kg) and crude protein concentrations from 119 to 232 g/kg (8-7 to 17-3 g lysine per kg) were offered ad libitum between 8-0 and 200 kg live weight. The rate of protein deposition was determined by comparative slaughter. The composition of the protein deposited in the whole empty body was determined from amino acid analyses of pigs killed at 8-0 kg and from the two extreme dietary treatments at 20-0 kg. Growth performance and the rates at which protein and lysine were deposited in the empty body increased linearly with increasing dietary protein concentration up to 187 g/kg and remained relatively constant thereafter. The corresponding dietary protein and lysine intakes required to support maximal protein accretion were 178 g/day (11-7 g/MJ DE) and 13-0 g/day (0-84 g/MJ DE) respectively. Based on the maximal deposition rates for protein (91-8 g/day), and lysine (5-96 g/day) and endogenous protein loss (7-6 g/day) estimated from the linear component of the relationship determined between protein deposition and apparent digestible protein intake, the pig's tissue requirements for protein and lysine were only 99-4 g/day (6-5 g/MJ DE) and 6-46 g/day (0-43 g/MJ DE) respectively. This disparity between the pig's tissue protein and amino acid requirements and the dietary levels needed to support these was associated with the fact that the apparent digestibility and biological value of the dietary protein were 0-92 and 0-602 respectively. Apart from small differences in the lysine content of body protein and the methionine : lysine ratio, the average amino acid composition of pigs killed at 8-0 kg, and from the diet of highest protein concentration at 20 kg, was similar to that of ideal protein, indicating that the low utilizability of dietary protein for tissue growth and maintenance was probably associated with low amino acid digestibility and/or availability. The implications of the results with respect to expression of the growing pig's requirements for protein and amino acids are discussed.

A sulfur amino acid deficiency changes the amino acid composition of body protein in piglets

“…Bunce and King (1969) fed young rats diets widely differing in protein content and observed that the amino acid composition of whole body protein was not constant. Similar results have been reported in growing pigs using diets differing in protein (Campbell et al, 1988;Bikker et al, 1994) or amino acid contents (Batterham et al, 1990;Chung and Baker, 1992b;Gahl et al, 1996). On the other hand, Wei and Fuller (2006) found no effect of a chronic amino acid deficiency on the amino acid composition in mature rats and argued that part of the observed responses may be due to differences in growth rate and body composition, rather than to the amino acid efficiency per se.…”

Dietary lysine and threonine utilization by young pigs: Efficiency for carcass growth

“…Experiments in which graded levels of lysine (Batterham et al 1990), methionine (Chung and Baker 1992a), and protein (Campbell et al 1988) were fed to pigs, lysine and methionine concentrations of carcass and whole body protein were observed to increase while glycine concentration was reported to decrease as nuffient intake increased. The range of lysine concentration of carcass protein in the current studies of 6.06-6.79 g 100 g-r protein parallels values of 6.2-6.5 [Campbell et al (1988) in whole body protein], 6.4 [Batterham et al (1990) Baker (1992a) in whole body proteinl,7.0 fKyiazakis et al (1993) in whole body proteinl, 6.86 [Krick et al (1993) in carcass proteinl, and 6.5 [Bikker et al (1994) Krick et al (1993), and Bikker et al (1994 …”

Protein turnover—what does it mean for animal production?

“…For example, the high content of threonine in mucins (Mukkur et al 1985) may account for the low absorption of this AA in young pigs (van Goudoever et al 2000). Indeed, when these pigs were offered a low-protein milk replacer diet there was no net absorption of threonine and the apparent needs of the GIT were much higher than for lysine (405 vs. 174 µmol kg -1 h -1 ), even though body proteins have, on average, a greater molar content (+33%) for lysine (Campbell and Taverner 1988). Net losses of threonine across the GIT were also increased when the dietary protein content was raised and, in the absence of threonine oxidation , this must be due to increased endogenous losses.…”