Ontogenetic Regulation Of Nutrient Transporters In The Small Intestine Of Broilers

In order to obtain the regional and ontogenetic expression of peptide transporter, amino acid transporters, sugar transporters, fatty acid transporter in intestine of Arbor Acre broiler, four experiments were conducted, meanwhile the effect of different diet on mRNA expression levels of nutrient transporters in broiler intestine and its molecular mechanisms were investigated.Exp.1The regional and ontogenetic mRNA expression of peptide transporter and amino acid transporters mRNA in broiler intestine. In order to study the expression changes of PepT1, CAT1, rBAT, B0AT, EAAT3mRNA in different segments and broiler ages, a total of120one-day-old AA male broilers were randomly assigned into8pens and the RT-qPCR method was employed8chicks from pens were killed, and their duodenum, jejunum, and ileum tissues were collected at1,3,7,14,21,28,35,42days. The results showed as follows:(1) the abundance of PepTl, CAT1, rBAT, B0AT, EAAT3mRNA is significantly different (P<0.05) in different intestinal segments. The PepTl mRNA expression was the highest in duodenum, lowest in ileum and intermediate in jejunum, whereas the abundances of CAT1, rBAT, B0AT, EAAT3mRNA were highest in ileum, lowest in duodenum and intermediate in jejunum;(2) The abundance of PepTl, CAT1, rBAT, B0AT, EAAT3mRNA is also significantly different (P<0.05) in different ages. The expression of PepTl, B0AT, and EAAT3mRNA increased with the ages in early growth stage, then became stable in late stage, while the expression levels of CAT1mRNA declined with age in early growth stage, then slightly increased. Further more the expression levels of rBAT expression increased in early growth stage, then decreased later.Exp.2The regional and ontogenetic expression of sugar transporters mRNA in intestine of broiler Based the Exp.l design, RT-qPCR method was employed used to study the diversity and developmental regulation of sugar transporters SGLT1、GLUT2、GLUT5mRNA expression of broilers. The results showed:(1) The abundance of SGLT1、GLUT2、GLUT5mRNA is significantly different (P<0.05) in different intestinal segments. The expression of SGLT1mRNA were greater in duodenum and jejunum, lower in ileum, whereas the abundances of GLUT2mRNA were greatest in jejunum, lowest in ileum and intermediate in duodenum, however, Levels of GLUT5mRNA were greater in duodenum lowest in duodenum and intermediate in ileum;(2) The abundance of SGLT1、GLUT2、GLUT5mRNA significantly difference (P<0.05) in different ages, for SGLT1mRNA expression:From1to35days, the expression of SGLT1mRNA increased in duodenum and jejunum, then decreased in42days, however, for ileal, the expression of SGLT1mRNA increased from1to14days, then decreased until35days, and42days recovered; changes of GLUT2mRNA abundance were:the jejunum and ileum increased from1to14days, then maintain steady until42days. While the expression of GLUT2mRNA increased from1to21days in duodenum, and a decrease trend from21to42days; Although the abundance of GLUT5mRNA changes different in different segments, the expression levels of21to42days was significantly higher (PO<005) than1to14days’.Exp.3The regional and ontogenetic expression of fatty acid transporters mRNA in intestine of broiler Based the Exp.l design, RT-qPCR method was employed used to study the diversity and developmental regulation of fatty acid transporters FATP4mRNA expression of broilers. The results showed:(1) the abundance of FATP4mRNA is significantly different (P<0.05) in different intestinal segments. The abundance of FATP4mRNA was greatest in jejunum, lowest in ileum and intermediate in duodenum.(2) The expression of FATP4mRNA significantly difference (P<0.05) in different ages, the expression of duodenum rise from1to28days, and relative stability after28days; in jejunum, a rising trend from1to14days then downregulation at21days, after a rapid increase in28days, then maintain stability, and there was a downward trend; in ileum, the expression of FATP4mRNA increased from1to7days, then decreased from7to21days, and after rising at28days, decreased from28to42days.Exp.4Effect of different diet on mRNA expression levels of nutrient transporters mRNA in intestine of broilers A total of120one-day-old AA male broilers were randomly designed into2treatments (group I were fed corn-based diets, group ii were fed wheat-based diet), and6replicates per group(10broilers per replicate), on21and42day, weight the body, and collected the intestinal samples. Contrast wheat and corn based diets, the results showed as follows:(1) the wheat diet reduced (P<0.05) body weight, average daily gain, and significantly increased (P<0.05) feed conversion ratio,(2) wheat diets reduced (P<0.05) the expression level of PepTl, GLUT5mRNA, increased (P<0.05) the expression of glucose transporter SGLTlmRNA.