A combined pig model to determine the net absorption of volatile fatty acids in the large intestine under different levels of crude fiber

Background:This study aimed to develop a combined model to quantify the net absorption of volatile fatty acids(VFA)in the large intestine(LI)of pigs.Methods:Fifteen female growing pigs(Duroc×Large White×Landrace)were ranked by body weight(30±2.1 kg)on day 0 and assigned to one of three treatments,namely the basal diet containing different crude fiber(CF)levels(LCF:3.0%CF,MCF:4.5%CF,and HCF:6.0%CF).The pigs were implanted with the terminal ileum fistula and the cannulation of the ileal mesenteric vein(IMV),portal vein(PV),and left femoral artery(LFA)from days 6 to 7.[13 C]-Labeled VFA and P-aminohippuric acid were constantly perfused into the terminal ileum fistula and the cannulation of the IMV(day 15),respectively.Blood samples were collected from the PV and the LFA during perfusion(5 h),and LI samples were collected.Results:The net flux of[12 C]-acetic acid in the PV was greater for LCF versus MCF(p=0.045),but no difference was observed in the net flux of[12 C]-propionic acid(p=0.505)and[12 C]-butyric acid(p=0.35)in the PV among treatments.The deposition of[12 C]-acetic acid in the LI was greater for LCF versus MCF(p=0.014),whereas the deposition of[12 C]-propionic acid(p=0.007)and[12 C]-butyric acid(p=0.037)in the LI was greater for LCF versus HCF.Conclusions:In conclusion,this pig model was found conducive to study the net absorption of VFAs in the LI,and LCF had more net absorption of VFAs in the LI than MCF and HCF.

Intrauterine growth restriction alters nutrient metabolism in the intestine of porcine offspring

Background:Intrauterine growth restriction(IUGR)has negative impacts on the postnatal survival,growth and development of humans and animals,with not only on newborns but also adulthood.However,the characteristics for nutrient digestion and absorption in IUGR offspring are still largely unknown.Therefore,the normal birth weight(NBW)and IUGR growing pigs were used in this study to investigate their differences in nutrient utilization,with an expectition for further nutritional optimization of the IUGR offspring during their later life.Methods:Twelve IUGR and 12 NBW growing pigs were fitted with catheters in their portal vein to measure blood flow rate as well as nutrients and metabolites in plasma.The digestibilities of nutrients in different intestinal segments,and bacterial fermentation in the large intestine were examined to reveal the characteristics of nutrients utilization in IUGR versus NBW pigs.Results:The rate of portal venous blood flow did not differ beween IUGR and NBW pigs.Plasma concentrations of total cholesterol,triglycerides and glucose were much lower but those of urea were higher in the portal vein of IUGR pigs,compared with the NBW pigs.The ileal digestibility of dry matter,gross energy and starch were lower in IUGR pigs than in NBW pigs.IUGR increased hindgut microbial diversity and bacterial fermentation activity in the caecum.In vitro cross-fermentation of ileal digesta by caecal microbes of NBW and IUGR pigs showed that gas production was much higher for IUGR ileal digesta regardless of the source of caecal inocula.Conclusion:IUGR impairs the nutrient digestion and absorption in small intestine,reduces caecal microbial diversity and promotes bacterial fermentation in the large intestine during the growing phase.These findings aid in our understanding of nutrient metabolism in IUGR pigs and provide the basis for future nutritional interventions.