Dietary Glutamine Supplementation Enhances Growth Performance and Jejunum Development in Kele and Large White Hybrid Weaned Piglets

Glutamine (Gln), a functional amino acid, is effective in reducing weaning stress in piglets. This study aims to assess the effects of dietary Gln supplementation on intestinal morphology and functionality, as well as the growth performance of Kele and Large White hybrid weaned piglets. Forty-eight piglets aged 30 days (Kele × Large White) were randomly divided into three groups: the control group, which received a basal diet supplemented with 2.45% alanine to maintain an isonitrogenous balance; the 1% Gln group, which received the basal diet with 1.0% Gln and 1.23% alanine; and the 2% Gln group, which was given the basal diet supplemented with 2.0% Gln. Intestinal samples from 16 piglets in the control and 1% Gln groups were collected randomly on day 29 of the experiment. The results show that, compared to the control group, the 1% Gln group experienced an increase in the average daily gain (ADG) and gain-to-feed ratio (G:F). In contrast, the 2% Gln group did not demonstrate significant differences in either the ADG or G:F compared to the control group. Additionally, there were no differences in feed intake among the groups. Notably, weaned piglets in both the 1% and 2% Gln supplementation groups had reduced diarrhea rates compared to those in the control group. Furthermore, 1% Gln supplementation significantly increased villus height in both the duodenum and jejunum and the ratio of villus height to crypt depth in weaned piglets. Subsequent analyses revealed that 1% Gln supplementation increased the mRNA expression of antioxidant genes, specifically catalase and superoxide dismutase. Additionally, the mRNA levels of the intestinal tight junction genes zonula occludens-1, Claudin 1, and Occludin in the jejuna of weaned piglets were found to be elevated. In summary, incorporating 1% Gln into the diet can significantly improve intestinal functionality and promote growth in Kele and Large White hybrid weaned piglets.