Regulatory Effect Of Low-Protein Diet Supplemented With Medium-Chain Fatty Acids On Energy Utilization Of Piglets

Piglets can not get sufficient energy from diet to maintain their growth and development after weaning for their dysplastic intestine.Medium-chain fatty acid glycerides can be oxidized rapidly in the liver to release energy for the development of piglets.Therefore,this experiment aimed at the intestinal barrier and nutritional metabolism,using caprylic acid glycerides,capric glycerides and lauric acid monoglycerides to explore the regulation of medium-chain fatty acid glycerides on energy utilization in piglets.Ninety21-day-old weaned piglets(about 6 kg of body weight)were randomly assigned into five treatments with six pens/treatment and 3 piglets/pen.The experimental period was 14 days.Treatments were as follows: NP(normal-protein);NC(low-protein diet);PC(low-protein diet +75 mg/kg quinocetone,20 mg/kg virginiamycin and 50 mg/kg aureomycin);MCT(NC+ tricaprylin + tricaprin);GML(NC + glycerol monolaurate).After the feeding experiment,the growth performance,serum biochemistry,serum free amino acids,digestive enzyme activity of jejunum and ileum,intestinal morphological barrier,volatile fatty acids of colon,intestinal energy index as well as related genes of triglyceride synthesis pathway were detected in piglets.The results as follows:(1).In terms of growth performance,the ADFI of MCT treatment was significantly higher than NC treatment(P<0.05).MCT and GML have significantly changed the biochemical parameters and free amino acid content in piglet serum.Compared with the NC treatment,GML significantly reduced serum LDH level(P<0.05),but significantly increased the CHOL and HDLI levels(P<0.05).Compared with the NP group,MCT significantly reduced serum TG and D-LACT levels(P<0.05).After adding MCT,serum levels of Ser,Gly,a-ABA,Ile,Leu and Orn were significantly lower than NP treatment(P<0.05).(2).MCT and GML treatment could significantly improve the intestinal barrier of piglets.Compared with the NC treatment,the number of goblet cells in the GML group was significantly increased in the jejunum(P<0.05);and in jejunum and ileum,MCT and GML significantly increased claudin-1 as well as ZO-1 m RNA expression levels(P<0.05).In ileum,compared with the NC treatment,the content of SIg A in MCT was significantly increased,and the content of IL-6 was significantly decreased(P<0.05).(3).Dietary MCT and GML could affect the metabolism of piglets on the absorption of nutrients and energy.Compared with NC treatment,GML significantly reduced the p H of ileum while the digestive enzyme activities(trypsin,lipase)of MCT and GML treatment in jejunum and ileum were significantly higher than NC treatment(P<0.05).Compared with PC treatment,the contents of isobutyric acid,isovaleric acid and total acid in GML treatment were significantly decreased in the colon contents(P<0.05).Compared with NC treatment,the ATP content of GML has significantly decreased in jejunum,but AMP content and AMP/ATP radio in ileum have increased(P<0.05).Besides,MCT and GML significantly increased the expression of CD36,CGI-58,MGAT2,DGAT1,LPIN2 as well as DGAT2 in adipose tissue(P<0.05).Collectively,the addition of medium-chain fatty acid glycerides can effectively improve the nutrient absorption,intestinal barrier function and lipid metabolism of piglets to meet the energy requirements of weaned pigs,and further provide a means to regulate the growth and development of weaned pigs.