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Reducing crude protein in swine diets can address environmental and economic issues in pig production. By lowering dietary crude protein while ensuring sufficient total nitrogen and essential amino acids, such as lysine, tryptophan, threonine, and methionine, producers can avoid excessive protein intake that leads to undigested amino acids and nitrogen in feces, which negatively impacts intestinal health. Lower crude protein levels can also influence microbial communities, reducing pathogen activity while maintaining beneficial bacteria, and may decrease odor emissions by affecting branched-chain volatile fatty acids. This study aimed to explore how a low-protein diet with added essential amino acids affects the growth, nutrient digestion, microbiota, and fatty acid composition in growing pigs.
Methods: A total of 160 pigs [(Landrace × Yorkshire )× Duroc] with an average initial weight of 16.7 kg were divided into four groups based on their starting weight and given one of four diets. The study followed a randomized complete block design with ten pigs per group and four groups per diet. The diets were: Control with 17.2% protein; Low protein (LP)-1.10 with 15.7% protein and 1.10% lysine; LP-1.15 with 15.7% protein and 1.15% lysine; and LP-1.20 with 15.7% protein and 1.20% lysine.
Results: Pigs on the control and LP-1.20 diets had higher final body weights compared to those on the LP-1.10 diet. While average daily gain, feed intake, and feed efficiency were similar between groups in phases 2 and 3, pigs on the control and LP-1.20 diets showed better performance in phase 1. The composition of isobutyric and isovaleric acids was lower in the LP diets compared to the control diet in phase 2, and total branched-chain fatty acids were significantly lower in LP diets during phases 1 and 2. No significant differences were observed in phase 3.
Conclusion: These results obtained highlight the benefits of adding essential amino acids to low-protein diets for improving early growth in pigs.
Mun J, Tajudeen H, Hosseindoust A, Ha S, Park S, Kim J. A reduction in dietary crude protein with amino acid balance has no negative effects in pigs. Journal of animal science and technology. 2024; 66(3): 493–503. https://doi.org/10.5187/jast.2023.e64