The use of free amino acids allows formulating very low crude protein diets for piglets1

Abstract

Reducing the dietary CP level with free AA supplementation allows reduction of N excretion and the risk of gut disorders while maintaining performance of pigs. We have recently reevaluated the Val, Ile, His, and Leu requirements in pigs, which enables formulating very low CP diets. However, requirements for undifferentiated N, and thus the extent to which the dietary CP content can be reduced, are unknown. Two experiments were conducted to test the effect of reducing the dietary CP content to meet an ideal AA profile on N retention and performance in 10- to 20-kg pigs. In the first experiment, we measured N retention in 6 blocks of 4 pigs each, all receiving diets with 1.15% standardized ileal digestible (SID) Lys. Each pig within a block was allotted to different levels of dietary CP (19.7%, 16.8%, 14.0%, and 12.7%). The reduction of CP content from 19.7% to 16.8% had no impact on N retention and decreased N excretion by 29%. A further decrease in CP content to 14.0% and 12.7% resulted in a reduced N retention (P < 0.01). In the second experiment, we measured performance in 14 groups of 6 pigs each, allotted to 6 levels of dietary CP with 1.00% SID Lys with soybean meal (17.6%, 15.6%, 13.5%, and 11.8%) or without soybean meal (14.0% and 13.0%). Decreasing the dietary CP content from 17.6% to 13.5% had no effect on performance. Daily gain was reduced in pigs receiving the 11.8% CP diet (P < 0.01). Feeding the diet formulated without soybean meal with 13.0% CP content resulted in reduced feed efficiency, but the addition of Glu to increase the CP content from 13.0% to 14.0% restored performance (P < 0.01). In conclusion, the use of L-Val, L-Leu, L-Ile, L-His, and L-Phe enables a 4% unit reduction in the CP content relative to SID Lys in diets for pigs. Soybean meal can be totally replaced using cereals and free AA. However, a further reduction in dietary CP:Lys level below 13.5% reduces feed efficiency, indicating that the supply of N for the synthesis of dispensable AA may be a limiting factor for the performance of pigs.

Effects of low-protein diets supplemented with indispensable amino acids on growth performance, intestinal morphology and immunological parameters in 13 to 35 kg pigs

“…Moreover, Wu (2014) emphasized both IAA and DAA should be taken into consideration in the formulation of balanced diets to maximize protein accretion in animals. It was reported that generation of DAA in pigs would be reduced by a deficiency of total N in low-CP diet (Columbus et al, 2012), and become a limiting factor for normal growth of pigs (Gloaguen et al, 2014). In this study, the decreasing growth performance of pigs fed 13.90% CP diet may be partially resulting from insufficient contents of total N, which was 30.5% lower than that of pigs fed 20.00% diet.…”

“…In addition, a moderate reduction of dietary CP level has been shown to decrease the harmful microbial metabolites in the digesta such as ammonia N (Nyachoti et al, 2006;Opapeju et al, 2008), as well as improving the villous morphology of weaned piglets (Gu and Li, 2004;Opapeju et al, 2008). In contrast, several studies have shown that pig growth performance can decrease when the dietary CP level is reduced by more than 4% , even though supplemented with IAA (Powell et al, 2011;Gloaguen et al, 2014), moreover, poor intestinal growth and morphology, reduced disaccharidase activities in small intestine were observed in pigs receiving extremely low-CP diets Yue and Qiao, 2008). However, there is little information whether there are alterations on immunological traits of pigs receiving extremely low-CP diet supplemented with IAA.…”

Branched chain amino acids in feeding pigs: Review

“…Pesquisas recentes (Gloaguen et al, 2014 demonstraram que a concentração da PB das rações está sendo reduzida por meio de formulações baseadas nas exigências dos AA essenciais, como os ACR, lisina e triptofano, bem como utilizando o conceito da PB (Van Milgen and Dourmad, 2015). Reduzindo a porcentagem de PB na dieta de leitões recém-desmamados e avaliando diferentes níveis de valina (Val) em relação à lisina (0,58; 0,62; 0,66; 0,70; 0,74 e 0,78%), Soumeh et al (2015) observaram uma resposta significativa na CA, CDR e GPD, assim como aumento na concentração plasmática de Val.…”

“…Pesquisas demonstraram a importância da concentração de proteína bruta (PB) e dos AA industriais, indispensáveis para uma formulação mais precisa, com base no conceito da proteína ideal (Richardson et al, 1965, Oestemer et al, 1973, Gomez et al, 2002, Zangeronimo et al, 2006, Lordelo et al, 2008, Gloaguen et al, 2014. Assim, a eficiência no aproveitamento dos ingredientes proteicos pelos não ruminantes depende da quantidade, da composição e da digestibilidade dos AA, de modo que as especificidades do aporte desses nutrientes sejam supridas.…”

Evaluation of in situ valine production by Bacillus subtilis in young pigs

“…In European starter and grower diets, Val is often among the five first limiting AA along with Lys, Met, Thr and Trp. These five AA are commonly included as crystalline AA in piglet diets, which allows reducing the content of CP while maintaining the dietary supply of indispensable AA to support optimum growth performance and reduce nitrogen excretion (Gloaguen et al, 2014;Nemechek et al, 2014).…”