Effect of Dietary Betaine on Muscle Protein Deposition, Nucleic Acid and Amino Acid Contents, and Proteomes of Broilers

SIMPLE SUMMARY: In animal production, growth trials have shown that betaine has a positive effect on growth performance, especially improving meat yield. Proteins are the largest unit comprising muscle cells except moisture. However, how betaine regulates muscle protein anabolism and abundance levels remains unclear. Therefore, this study was conducted to investigate the effect of dietary betaine on growth performance, muscle protein deposition, and proteome of broilers. The results suggested that betaine could improve growth performance and muscle protein deposition of broilers. Alterations in muscle nucleic acids, amino acids, and protein abundance levels were involved in this process. Proteomic analysis further revealed that 35 proteins in breast muscle were identified as differentially abundant proteins by betaine supplementation, which were mainly related to cell differentiation, small molecule metabolic process, and tissue development. ABSTRACT: To investigate the effect of betaine supplementation on growth performance, muscle protein deposition, muscle nucleic acid and amino acid contents, and muscle proteome of broilers, 160 one-day-old male partridge shank broiler chickens were randomly divided into 2 groups with 8 replicates of 10 broilers each. Broilers were fed a basal diet alone, or a basal diet supplemented with 1000 mg/kg betaine. Compared with the control group, the betaine group significantly increased (p < 0.05) the broilers average daily gain, the levels of serum insulin-like growth factor-1 (IGF-1), growth hormone (GH), total protein (TP), the contents of muscle absolute protein deposition, RNA, Ser, Glu, Met, and Phe, and the ratio of RNA/DNA, and decreased (p < 0.05) the feed conversion ratio and serum blood urea nitrogen content. Moreover, proteomic analysis revealed 35 differentially abundant proteins (DAPs) in the betaine group compared with the control group, including 27 upregulated proteins and 8 downregulated proteins (p < 0.05). These DAPs were mainly related to cell differentiation, small molecule metabolic process, and tissue development. In conclusion, diets supplemented with 1000 mg/kg betaine improved growth performance and muscle protein deposition of broilers. Increased serum GH, IGF-1, and TP contents, and alterations in muscle nucleic acids, amino acids, and protein abundance levels were involved in this process.