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

Abstract

Experiments carried out to determine the amino acid requirement in growing animals are often based on the premise that the amino acid composition of body protein is constant. However, there are indications that this assumption may not be correct. The objective of this study was to test the effect of feeding piglets a diet deficient or not in total sulfur amino acids (TSAA; Met 1 Cys) on nitrogen retention and amino acid composition of proteins in different body compartments. Six blocks of three pigs each were used in a combined comparative slaughter and nitrogen balance study. One piglet in each block was slaughtered at 42 days of age, whereas the other piglets received a diet deficient or not in TSAA for 19 days and were slaughtered thereafter. Two diets were formulated to provide either 0.20% Met and 0.45% TSAA (on a standardized ileal digestible basis) or 0.46% Met and 0.70% TSAA. Diets were offered approximately 25% below ad libitum intake. At slaughter, the whole animal was divided into carcass, blood, intestines, liver, and the combined head, tail, feet and other organs (HFTO), which were analyzed for nitrogen and amino acid contents. Samples of the longissimus muscle (LM) were analyzed for myosin heavy chain (MyHC) and actin contents. Nitrogen retention was 20% lower in piglets receiving the TSAA-deficient diet (P , 0.01). In these piglets, the nitrogen content in tissue gain was lower in the empty body, carcass, LM and blood (P , 0.05) or tended to be lower in HFTO (P , 0.10), but was not different in the intestines and liver. The Met content in retained protein was lower in the empty body, LM and blood (P , 0.05), and tended to be lower in the carcass (P , 0.10). The Cys content was lower in LM, but higher in blood of piglets receiving the TSAA-deficient diet (P , 0.05). Skeletal muscle appeared to be affected most by the TSAA deficiency. In LM, the Met content in retained protein was reduced by 12% and total Met retention by more than 60%. The MyHC and actin contents in LM were not affected by the TSAA content of the diet. These results show that a deficient TSAA supply affects the amino acid composition of different body proteins. This questions the use of a constant ideal amino acid profile to express dietary amino acid requirements, but also illustrates the plasticity of the animal to cope with nutritional challenges.

The amino acid composition of tissue protein is affected by the total sulfur amino acid supply in growing pigs

“…Moreover, the reduction in protein content was moderate for both the muscles (6%), which is smaller than the 20% reduction in protein content of LM observed by Conde-Aguilera et al (2010) during a severe TSAA deficiency in weaned piglets. Skin sections were collected from five locations (i.e.…”

“…In this study, a deficient TSAA supply resulted in the use of both strategies by the animal and a Met deficiency of 19% resulted in a 15% reduction in ADG. In a previous study on weaned piglets with a short but more severe deficiency (40%), we observed a 20% reduction in ADG (Conde-Aguilera et al, 2010). Therefore, a prolonged and moderately deficient TSAA supply may have a proportionally greater effect on ADG than a short and severely deficient TSAA supply.…”

“…It is likely that the reduction in protein content in the muscle is accompanied by an increase in lipid deposition, as observed by others (e.g. Martinez-Ramirez et al, 2008;Conde-Aguilera et al, 2010). The protein content of other tissues (i.e.…”

“…It has been proposed that changes in the relative tissue mass in combination with differences in AA composition among tissues contribute to changes the AA composition of wholebody protein (Wei and Fuller, 2006). Results of a study in our laboratory indicated that specific tissues respond differently to a deficient total sulfur AA (TSAA) supply (Conde-Aguilera et al, 2010). If the AA composition of tissue protein such as the muscle is affected by the AA supply, it is possible that meat quality traits are affected as well.…”

Impact of amino acid and CP restriction from 20 to 140 kg BW on performance and dynamics in empty body protein and lipid deposition of entire male, castrated and female pigs

“…Possible reasons could be overestimated nutrient requirements, large safety margins in feeding recommendations or tissue-specific increased efficiency in using limiting resources. For instance, Conde-Aguilera et al (2010) reported that diets deficient or not in total sulphur amino acids had dissimilar impact on the amino acid composition of different body proteins in young piglets. However, to our knowledge, there is no recent information on the dynamics in empty body (EB) protein and lipid deposition of growerfinisher pigs fed diets restricted in CP or essential amino acid (EAA) during the whole growth period.…”