Effects of Dietary Tryptophan Levels on Organ Index and Small Intestine Related Gene Expression in Weaning Pigs (Sus scrofa)
MA Wen-Feng1,2,*, GUO Liang3, WANG Zhan-Bin1, ZHAO Fu-Rong1
1 College of Animal Science and Technology, Henan University of Science and Technology, Luoyang 471023, China; 2 College of Animal Science and Technology, China Agricultural University, Beijing 100193, China; 3 College of Animal Science and Veterinary Medicine, Tianjin Agricultural University, Tianjin 300384, China
Abstract Tryptophan is the second or third limiting amino acid for weaning pigs (Sus scrofa), which plays an important role in the regulation of feeding intake, growth, immunity and intestinal development. The 4 different ratio of tryptophan to lysine was conducted to investigate the effects of dietary tryptophan level on serum biochemical index, organ IDO and intestinal tight junction protein gene expression in weaning pigs. A total of 240 weaning pigs (Large White×Landrace×Duroc) with an initial body weight of (6.5±0.2) kg were randomly divided into 4 treatments with 6 repetitions and 10 pigs each repetition and the experiment lasted for 28 d. The dietary ratios of tryptophan to lysine were 0.15, 0.18, 0.21, and 0.24. The result showed that compared with the group with tryptophan to lysine ratio of 0.15, when the ratio was increased to 0.18, 0.21 or 0.24, the expression of IDO gene in the spleen, kidney, stomach and ileum of weaning pigs was significantly reduced (P<0.05), and the expression of jejunum IDO mRNA in the 0.24 group was significantly increased (P<0.05). When the dietary ratios of tryptophan to lysine increased from 0.15 to 0.24, the expression of occludin and ZO-1 in the duodenum and ileum were significantly reduced (P<0.05), the jejunum expression levels of ZO-1 mRNA in the 0.18 and 0.24 groups were significantly decreased (P<0.05), while the jejunum occludin mRNA expression levels in the 0.21 group were significantly increased (P<0.05). When the ratio of dietary tryptophan to lysine increased from 0.15 to 0.24, the level of serum urea nitrogen was influenced in weaning pigs (P<0.05). It was found that when the ratio of tryptophan to lysine was adjusted from 0.15 to 0.24, the gene expression of IDO and small intestinal tight junction protein in the organism could be significantly regulated, and nitrogen metabolism of the organism could be also affected in this study. In conclusion, the optimal ratio of tryptophan to lysine for weaning pigs was 0.18. The results provides a theoretical basis for the application of tryptophan in the diet of weaning pigs.
MA Wen-Feng,GUO Liang,WANG Zhan-Bin, et al. Effects of Dietary Tryptophan Levels on Organ Index and Small Intestine Related Gene Expression in Weaning Pigs (Sus scrofa)[J]. 农业生物技术学报, 2021, 29(8): 1538-1545.
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