Changes In Hindgut Development And Function Of Early Weaned Piglets

There are many studies on the morphological structure and function of the small intestine of early weaned piglets,but few studies on the hindgut.This article aims to study the changes in growth and function of large intestine in early weaned piglets.Forty piglets were weaned at 21-day-old age and randomly assigned to five groups.Piglets were euthanized respectively at day(d)0,1,3,7,and 14 after weaning and samples were collected for subsequent experimental analysis.The results showed:1)The body weight,average daily gain,and average daily feed intake of piglets at d 7 and 14 after weaning were higher than on d 0,1 and 3(P<0.001).2)In the colon,the concentration of acetic acid,propionic acid,butyric acid,and total volatile fatty acids(VFA)were higher on d 3,7,and 14 after weaning than on d 0.The concentration of pentanoic acid and isobutyric acid increased on d 14 and decreased on d 1 compared with d 0,and isopentoic acid increased on d 14 and decreased on d 3(P<0.001).The expression of FFAR3 gene was lower on d 7 and 14 than on d 1(P<0.05),and the expression of MCT1 and SMCT1 genes was higher on d 7 and 14 than on d 0(P<0.001).3)The absolute weight,relative weight and perimeter in the colonwere higher on d 7 and 14 after weaning than on d 0,and the absolute length was higher on d 14 than on d 0(P<0.001).Colonic crypt depth and width were higher on d 7 and 14 than on d 0(P<0.001).Compared with d 0,the number of Ki67 cells increased on d 7,14 and decreased on d 1,and the number of goblet cells increased on d 1(P<0.001).The fission index of colonic crypts was lower on d 14 than on d 0(P<0.05),and the total number of colonic crypts was higher on d 14 than on d 0(P<0.001).5)In the cecum,the value of crypt depth,width,and volume were higher on d 7 and 14 after weaning than on d 0,1,and 3.The number of Ki67 cells was lower on d 1 and 3 than on d 7(P<0.05).The concentration of acetic acid,propionic acid and butyric acid were higher on d 3,7,and 14 than on d 1.The concentration of isobutyric acid,pentanoic acid and isopentoic acid decreased from d 0 to d 3.The total VFA concentration was higher on d 0,3,and 14 than on d 7(P<0.001).The expression of MCT1 gene increased from d 0 to 1 and from d 3 to 7,and decreased from d 1 to 3 and from d 7 to 14(P<0.001).6)In the cecum,the concentration of malondialdehyde(MDA)was highest on d 3 after weaning(P<0.001).The activity of catalase(CAT)was lower on d 0 and 1 than on d 3,7,and 14(P<0.001).The activity of CuZn-SOD increased within 24 h after weaning,and the total SOD and CuZn-SOD activities were higher on d 1 than on d 3 and 7(P<0.05).The concentration of lipopolysaccharide(LPS)increased from d 3 to 7 and decreased from d 7 to 14(P<0.05).The expression of TLR4 gene increased within 24 h after weaning(P<0.05).The expression of IFN-? gene increased within 24 h after weaning and decreased from d 1 to 3.The expression of TNF-? gene was higher on d 14 than on d 7(P<0.05).In summary,there are significant changes in the development of colon in piglets after early weaning,which may be related to the changes in colonic digesta VFA concentration.In addition,the function and health of cecum have also changed significantly.