Effects of protein content and the inclusion of protein sources with different amino acid release dynamics on the nitrogen utilization of weaned piglets

Abstract

Objective: We aimed to investigate the effect of the differing amino acid (AA) release dynamics of two protein sources on the growth performance, nitrogen deposition, plasma biochemical parameters, and muscle synthesis and degradation of piglets when included in their diets at normal and low concentrations.Methods: Forty-eight piglets (Duroc×Landrace×Large White) with initial body weight of 7.45±0.58 kg were assigned to six groups and fed one of 6 diets. The 6 dietary treatments were arranged by 3×2 factorial with 3 protein sources and 2 dietary protein levels. They are NCAS (a normal protein content with casein), NBlend (a normal protein content with blend of casein and corn gluten meal), NCGM (a normal protein content with corn gluten meal), LCAS (a low protein content with casein), LBlend (a low protein content with blend of casein and corn gluten meal), LCGM (a low protein content with corn gluten meal). The release dynamics of AA in these diets were determined by in vitro digestion. The digestibility, utilization and biological value of nitrogen in piglets were determined by micro Kjeldahl method. Plasma insulin was measured by enzyme-linked immunosorbent assay kits. The protein expression of mediators of muscle synthesis and degradation was determined by western blotting.Results: Although the consumption of a low-protein diet supplemented with crystalline AA was associated with greater nitrogen digestion and utilization (p<0.05), the final body weight, growth performance, nitrogen deposition, and phosphorylation of ribosomal protein S6 kinase 1 and eIF4E binding protein 1 in the muscle of pigs in the low-protein diet-fed groups were lower than those of the normal-protein diet-fed groups (p<0.05) because of the absence of non-essential AA. Because of the more balanced release of AA, the casein (CAS) and Blend-fed groups showed superior growth performance, final body weight and nitrogen deposition, and lower expression of muscle ring finger 1 and muscle atrophy F-box than the CGM-fed groups (p<0.05).Conclusion: We conclude that the balanced release of AA from CAS containing diets and mixed diets could reduce muscle degradation, favor nitrogen retention, % intake and improve growth performance in pigs consuming either a normal- or low-protein diet.

Effects of diets with different amino acid release characteristics on the gut microbiota and barrier function of weaned pigs

“…The piglets were assigned to six groups: those fed normal-protein level diets (standard terminal ileal digestibility of 17.5%) containing CAS (N.CAS), CGM (N.CGM), or mixture of both of these two diets (CAS + CGM; N.MIX); and those fed low-protein diets (standard terminal ileal digestibility of 14.9%) containing CAS (L.CAS), CGM (L.CGM), or mixture of both of these two diets (CAS + CGM; L.MIX). According to our previous results [ 2 ], CAS and MIX diets result in more balanced release of AA during hydrolysis in vitro than the CGM diet.…”

“…According to the results of amino acid release dynamics in Hu et al 2022, according to the results of amino acid release dynamics in Hu et al 2022 [ 2 ], the larger the area between individual FAA curve and TFAA curve, the more asynchronous the amino acid release dynamics are. Then we analyzed the correlation between amino acid release dynamics and intestinal microbial diversity at the phylum level and genus level.…”

“… AARA Amino acid release asynchronism. According to the results of amino acid release dynamics in Hu et al 2022 [ 2 ], the larger the area between individual FAA curve and TFAA curve, the more asynchronous the amino acid release dynamics are. ** P < 0.01, * P < 0.05 …”

“…According to the traditional theory of pig amino acid nutrition, diets formulated according to the ideal amino acid pattern that is consistent with the composition and proportion of amino acids and the pig body composition can result in optimal growth performance [ 1 ]. However, our previous studies have shown that although the protein content and digestible amino acids in terminal ileum of diets formulated with different protein sources are the same, there are significant differences in in vitro amino acid release patterns, and the in vivo nitrogen deposition rate is still not ideal [ 2 , 3 ]. This is due to the decomposition of amino acids in the intestinal tract, which leads to the low utilization of dietary amino acids in pigs [ 4 ].…”

“…Based on previous studies, the same terminal ileum digestible diets supplemented with casein result in better synchronicity of amino acid release than those supplemented with corn gluten meal. In addition, diets with good synchronicity of amino acid release can improve nitrogen use efficiency in pigs [ 2 , 3 , 13 ]. Therefore, we selected a traditional corn-soybean meal diet supplemented with CAS, CGM or a mixture of both (CAS + CGM; MIX), to create diets with three different amino acid release characteristics, with the aim of further exploring the effects of different amino acid release rates on intestinal barrier function and intestinal microflora of piglets.…”