The Effect Of Dietary Crude Protein Content On Jejuna Epithelial Cells In Weaned Piglet

Intestinal epithelium is a selective barrier which directly contacts luminal contents, and plays vital roles in digesting and absorbing nutrients and preventing pathogens intrusion.Low protein balance diets can improve the incidence and severity of diarrhea in piglets but no change the growth performance. Diarrhea mainly because of a jejunal development is not perfect and dietary protein digestion and absorption incomplete, and the proximal jejunum is the major site of amino acid and peptide absorption, but other parts of the small intestine also have significant transport capacity. However, low protein diet on protein metabolism of weaned piglets jejunum epithelial cells remains to be investigated. Therefore, this paper takes 10kg weaned piglets, isolated jejunal different differentiation of epithelial cells along crypt villus axis by classification, combined with amino acid analyzer, PCR and other technical to analysis the effect dietary crude protein contents on free amino acid, amino acid transporters, mTOR signal pathway and ubiquitin proteasome degradation pathway in jejunum along crypt villus axis cell isolated from piglets.A total of fifty-four healthy crossbred (Duroc* Landrace* Yorkshire) 10kg piglets were chosen and randomly divided into 3 groups,18 repeats in each group, of which dietary crude protein level was 14%,17% and 20%, respectively, and each group choose 6 head separation air intestinal crypt villus axis different differentiation of epithelial cells in 10d,25d,45d.The results showed that:1) Crude protein level in diets of different degree of differentiation of different jejunal cells significantly affected the content of free ammonia acid of different. Feeding 10d,17% dietary crude protein levels on significantly increased the content of F1 of various types of free ammonia acid; fed 25d,14% dietary crude protein levels on significantly increased the content of F’1 of various types of free ammonia acid; and feeding 45d,14% crude protein level diet significantly increased the content of F"1 various types of free ammonia acid.2) Effects of dietary protein levels on different periods of different degree of differentiation cells in jejunum of weaned piglets were inconsistent, among them, fed different dietary crude protein levels on 10d,17% crude protein level diet significantly increased the expression quantity of neutral amino acid transporter F1 and F2 mRNA; feeding 25d,14% crude dietary protein level significantly increased the amount of neutral amino acid transporter expression in jejunum and cationic amino acid transporter mRNA; feeding 45d,14% dietary crude protein levels on the expression of ATP significantly increased the amount of enzyme of intestinal epithelial cells on the membrane of mRNA.3) Effects of different dietary protein levels on different periods of different degree of differentiation cells in jejunum of weaned piglets mTOR signaling pathways and the ubiquitin proteasome pathway is not consistent. mTOR signaling pathway, with 10d, there were no significant differences between the three parts of the cells of the jejunum feeding; 25d,14% dietary crude protein levels on significantly improves the expression quantity fluff on the HIF1 alpha and EIF-4E-BP1 mRNA,17% crude protein levels were significantly reduced the expression of crypt cell HIF1 alpha and p70S6K mRNA the feeding; 45d,17% dietary crude protein levels on significantly improves the expression quantity in the villi end HIF1 alpha mRNA. The ubiquitin proteasome pathway, with 10d, there were no significant differences between the three parts of the cells of the jejunum; feeding 25d,14% dietary crude protein levels on significantly improves the expression quantity of El and E2 in the villus tips mRNA, 17% crude protein level diet significantly reduced crypt cell E2 mRNA expression 45d; feeding,14% crude protein level diet significantly reduced the expression of E2 and mRNA in the villus tip 20% crude protein levels were significantly reduced the expression of E2 mRNA,17% crude protein level diet significantly reduced the expression of E1 and E2 in middle villus mRNA.Conclusion:in the early weaning, should be appropriate to reduce the level of dietary crude protein, make better lactation piglets from the transition to the ingestion of solid phase, while in the mid to late weaning, may continue to reduce dietary crude protein level, save the protein sources, alleviate the shortage of protein material.