| Early-weaning stress is the key problem in pig feeding industry. Although it can increase sow's productivity, it may associate with the reduced voluntary food intake, the immunosuppression and increased susceptibility to harmful pathogen. As a result, early weaning piglets commonly experience diarrhoea and a reduced growth rat during a short period postweaning.In fact, the small intestine undergoes perhaps the most dramatic challenged by chemical and physical alterations in diets, which cause great changes in its structure and function. The small intestine serves not only as an organ of digestion, nutrient absorption, but as the biggest independent immune organ.Glutamine is the most abundant amino acid in blood and muscle tissue in mammalian. It has multiple functions. It surveys as an essential precursor for the synthesis of protein, purine and pyrimidine nucleotides, NAD+ and aminosugars. It is the key fuel for the intestinal mucosa and other rapidly dividing cells such as renal tubcular cells, malignant cells, intestinal epithelial cells, and cells in immune system such as lymphocytes, macrophages and neutrophils. Recent studies have indicated that glutamine may be and essential dietary component for the mucosal immune function and the gut metabolism, structure and function.Because weaning removes the glutamine rich sow's milk from the piglet diet, and feed intake is minimal during a short period postweaning, the damaged intestinal structure and local immune function may result in part from a minimal supply of glutamine. In order to use glutamine as a new tape of feed additive to mitigate the negative effect ofearly weaning on piglet, multiple studies were performed to evaluate the effects of glutamine supplementation on early weaning piglets and the mechanism involves were investigated. The main results are followed:After several doses of glutamine (0.7%, 1.0%, 1.3%) were supplemented in 28 d weaned piglets, we found that 1% glutamine significantly increased the average daily gain on d 7 postweaning (P<0.05) and the diarrhea was induced. The histological result indicated that VH in jejunum was greater (P<0.05) on d 7 postweaning in 1% glutamine supplemented pigs compared with control pigs. The LPD of duodenum progressively increased (P<0.05) with increasing age in both control and glutamine supplemented pigs. In control pigs, the LPD of jejunum also progressively increased (P<0.05) with increased age. However, in glutamine-supplemented pigs, there was no difference (P>0.05) in head and middle of jejunal LPD between d 7 and 14 postweaning. The mucosal DNA concentration in glutamine-supplemented pigs was greater (P<0.01 or P<0.05) than control pigs on d 7 and 14 postweaning respectively. The mucosal RNA concentration in glutamine-supplemented pigs was greater (P<0.05) than control pigs on d 7 postweaning. The D-xylose analysis indicated that the D-xylose concentration was greater (P<0.01) in glutamine-supplemented pigs compared with control pigs both on d 7 and d 14 postweaning. All the results above indicated that as the main fuel for the intestinal mucosal cells during weaning stress, exogenous glutamine might accelerate the proliferation of mucosal cells and repairing of gut after stress-related damages, maintain the intestinal modality, structure and active absorption function.The glutamine concentration in muscle tissue, plasma and intestinal mucosa indicated that, the glutamine concentration in muscle tissue and intestinal mucosa was greater (P<0.05) in glutamine-supplemented pigs than control pigs on d 5 postweaning. So did the glutamine concentration in plasma on d 2 postweaning. Glutamine-supplementation tended to increase the RNA concentration in muscle tissue on d 7 postweaning. All the results above implied that exogenous glutamine could induce the intestinal glutamine extraction from blood, maintain the glutamine store in muscle tissue and plasma, decrease the glutamine flux from muscle tissue and protein catabolism.Dietary glutamine-supplementation could stimulate the IL-6...
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