Effects Of Dietary Nutrition Level On MRNA Abundace Of Amino Acid Transporters And Na~+/H~+ Exchangers In Epithelium Of Forestomach

In this study, two experiments are included:1. The expression of four amino acid transporters mRNA in the forestomach epithelium and effects of dietary nutrition level on mRNA abundance of them.2. Effects of dietary nutrition level on mRNA abundance of Na+/H+exchangers in goat forestomach epithelium.Experiment 1:The expression of several amino acid transporters mRNA in goat forestomach epithelium and effects of dietary nutrition level on mRNA abundance of them.The expression of four amino acid transporters (ASCT2, CAT1, EAAT3 and ATBO) were detected by RT-PCR. The results showed that the four genes were all expressed in the forestomach epithelium of goats, cows and cattle.Sixteen 70-day-old weaning hybrid goats were divided into low nutrition level group (n= 8) and high nutrition level group (n= 8). All of the goats were feed, with peanut stems and water were avaliable at any time. The goats in the high nutrition level group were fed with 75 grams concentrate at 8:00,11:00,13:00 and 17:00 every day respectively. After 6 weeks feeding, all the goats were slaughtered for sampling.It was found that the average daily intake, protein intake and energy intake of experimental group (high diet nutrition level) were significantly higher than those in the control group(low diet nutrition level) (P< 0.05); The daily body weight gain and dry weight of rumen/body weight in experiment group were also significantly higher than those in the control group (P< 0.05). But dry weight of omasum/body weight of goats in experimental group were significantly lower than those in the control group (P< 0.05). The VFA in the rumen and omasum fluid were detected by gas chromatography. It was found that the concentration of propionate, acetate and butyrate of rumen and omasum fluid in the experimental group were significantly higher than those in control group (P<0.01); The PH of rumen and omasum fluid in the experimental group were significantly lower than those in control group (P< 0.05); Using relative quantitative RT-PCR method, it was found that the ASCT2 mRNA expression level of rumen epithelial in the experiment group is significantly higher than those in the control group (P< 0.05), and the expression level of ASCT2 mRNA in omasum epithelium is significantly below the control group (P< 0.05); Meanwhile EAAT3 mRNA expression level in the rumen and omasum epithelium had no difference between the two groups (P= 0.22 and P= 0.67); The CAT mRNA expression level are very low in both groups.Experiment 2:Effects of dietary nutrition level on mRNA abundance of Na+/H+ exchangers in goat forestomach epithelium.Experimental design is same with experiment 1. The mRNA expression of NHE1, NHE2 and NHE3 in goat rumen epithelial were detected by real-time PCR. It was found NHE1, NHE3 mRNA level in the experimental group is significantly higher than the control group (P< 0.05), and the expression level of NHE2 mRNA had no difference between the two groups (P= 0.93).