Interaction and imbalance between indispensable amino acids in young piglets

Abstract

Lowering protein level in diets for piglets urge to have knowledge on the piglet's requirements for essential amino acids (AA) and their interactions. The present studies aimed to determine the interaction between the dietary level of valine (Val) and tryptophan (Trp) and the effect of AA imbalance at two levels of dietary Val on the growth performance of post-weaning piglets. In Experiment 1 (duration 4 weeks), the effects of supplementation of free L-Val (1.0 g/kg) and/or L-Trp (0.5 g/kg) in a low-CP diet (CP 17.7%), marginal in Trp and Val, was studied in a 2 × 2 factorial design and using an additional reference treatment (CP 19.5%). In Experiment 2 (duration 5 weeks), the influence of a stepwise increase in excess supply of isoleucine (Ile), histidine (His) and leucine (Leu), up to 10, 10% and 30% relative to their requirement values respectively, was evaluated at 60% or 70% standardized ileal digestible (SID) Val relative to SID lysine, using a 3 × 2 factorial design. In Experiment 1, over the whole experimental period, feed intake (FI) was affected by dietary Trp level (P < 0.05) and feed conversion ratio (FCR) by both the level of Trp and Val in the diet (both P < 0.05). Increasing Trp level increased FI and decreased FCR while increasing dietary Val level reduced FI and increased FCR. For BW gain (BWG), there was an interaction between dietary level of Trp and Val (P < 0.05). Valine supplementation decreased BWG using a diet marginal in Trp, whereas it increased BWG when using a Trp sufficient diet. Piglets fed the low-CP diet with adequate levels of Val and Trp showed at least same performance compared to piglets fed the high CP reference diet. In Experiment 2, increasing dietary Val improved FI and BWG (P < 0.001) and tended to improve FCR. Dietary AA excess for Ile, His and Leu reduced FI and BWG (P < 0.05) and only affected FCR (P < 0.01) in the 1 st week of the study. Dietary level of Val and AA excess did not show interactive effects, except for FCR over the final 2 weeks of the study (P < 0.05). In conclusion, an interaction exists between dietary supply of Val and Trp on the zootechnical performance of post-weaning piglets and dietary AA excess for Ile, Leu and His, reduces growth performance of piglets in low-protein diets, independent of the dietary level of Val. ImplicationsThe increasing availability of feed-grade amino acid (AA) allows a reduction of CP content in animal diets. Besides the beneficial effects of dietary protein reduction on animal health and environment, the use of feed-grade AA provides a more balanced supply of AA relative to their requirements. This study shows that responses of the zootechnical performance of piglets towards dietary supplementation of free Ltryptophan (L-Trp) and L-valine (L-Val) are dependent of the dietary concentrations of these AA and that dietary amino excess for leucine (Leu), isoleucine (Ile) and histidine (His) reduces performance of piglets on low-protein diets. This demonstrates the importance of supplying adequate dietary levels of AA in line w...

Dose-response of different dietary leucine levels on growth performance and amino acid metabolism in piglets differing for aminoadipate-semialdehyde synthase genotypes

“…This could have counteracted the positive effect seen on muscle protein synthesis stimulation with less protein degradation observed with Leu supplementations 4–6 . When in excess, Leu may in fact lead to an imbalance in BCAAs and then to a reduction of feed intake 8–11 , with negative influence on growth performance 2,11 . This may indicate that for the pigs used in the present trial, the Leu requirement could have been slightly over the 100% SID Leu:Lys recommended by NRC 16 .…”

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Birth weight affects body protein retention but not nitrogen efficiency in the later life of pigs

“…The quantitative effects of dietary protein restriction on N retention in the body may be dependent on the (Van Milgen et al, 2012), whereas a 10% reduction in the SID lysine concentration reduced ADG with about 3% to 4% (Van Milgen et al, 2008). Moreover, when the dietary supply of essential AA is limited, negative effects of interactions between essential AA in metabolism on net N retention may become stronger (Jansman et al, 2019).…”

Production performance and plasma metabolite concentrations of broiler chickens fed low crude protein diets differing in Thr and Gly

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