Effects Of Intrauterine Growth Retardation On Growth Performance,plasma Parameters And Intestinal Microecology Of Growing-finishing Pigs

Intrauterine growth retardation(IUGR)causes serious economic losses to modern animal husbandry.The present study was conducted to compare the alterations in growth performance,plasma parameters and intestinal microbiota of normal body weight(NBW)and IUGR growing-finishing pigs.The results showed that:Experiment 1: The purpose of this study was to investigate the effects of IUGR on growth performance,organ index and plasma parameters of growing-finishing pigs.The experiment selected a total of 36 pregnant sows with similar body conditions for normal delivery.After delivery,one IUGR piglet and one NBW piglet were selected from each litter.When the average body weight(BW)of NBW pigs reached 25 kg,50 kg,and 100 kg respectively,twelve pigs were randomly selected from IUGR and NBW groups to weigh and blood samples were collected from the precaval vein and the sample were detected routine blood indices.The plasma was separated by centrifugation,and for analyzing biochemical parameters,contents of free amino acids and hormone related to feed intake and growth regulation,antioxidant indexes.The results showed that:(1)IUGR significantly affected the growth performance and development of organs of growingfinishing pigs.Compared with the NBW pigs,at 25 and 50 kg BW,IUGR pigs had lower initial BW,final BW,ADG,liver,spleen,and kidney weight(P<0.05);at 50 kg BW IUGR pigs had a higher liver index(P<0.05);at 100 kg BW,IUGR pigs had higher indices of spleen,liver,and kidney,and lower initial BW,final BW,ADG,kidney and liver weight(P<0.05).(2)IUGR significantly affected the nutritional metabolism,antioxidant and immunity capacity of growing-finishing pigs.Compared with the NBW pigs,at 25 kg BW,the plasma contents of ALP,Cit,and level of T-AOC in IUGR pigs increased(P<0.05),while the plasma contents of GLU and IL-1β decreased(P<0.05);at 50 kg BW,the plasma contents of TG,CHO,and ALT in IUGR pigs increased(P<0.05),while the plasma contents of TP,ALB,GLU,and ratio of IL-1β to IL-10 decreased(P<0.05);at100 kg BW,the plasma contents of UN in IUGR pigs increased(P<0.05),while the plasma content of TP and ALB decreased(P<0.05).(3)IUGR affected the contents of hormone related to feed intake and growth regulation of growing-finishing pigs.Compared with the NBW pigs,at 25 kg BW,the plasma contents of growth hormone,somatostatin,peptide YY,and pancreatic polypeptide in IUGR pigs increased(P<0.05),while the plasma content of insulin decreased(P<0.05);at 50 kg BW,the plasma contents of IGF-1,leptin,and insulin in IUGR pigs increased(P<0.05),while the plasma contents of gastrin,growth hormone,and pancreatic polypeptide decreased(P<0.05).(4)IUGR affected the routine blood indices of growing pigs.Compared with the NBW pigs,at 25 kg BW,IUGR pigs had higher mean corpuscular volume,mean corpuscular hemoglobin(MCH)and platelet distribution width(P<0.05),whereas lower red blood cells(RBC),red blood cell distribution width(P < 0.05);at 50 kg BW,IUGR pigs had higher neutrophils% and MCH(P<0.05),while presented lower intermediate cells and platelets count,white blood cells,RBC,mean platelet volume,and plateletcrit(P<0.05).Experiment 2: The purpose of this study was to evaluate the effects of IUGR on the microbial diversity,microecology,and gene function of small intestinal microbiota of growing-finishing pigs.After slaughtering,the intestinal luminal contents and intestinal mucosa of the middle part of jejunum and ileum were collected and used for analysis of gut microbial 16 S rDNA sequencing.The results showed that:(1)IUGR affected the diversity of intestinal microbiota in growing-finishing pigs.Compared with the NBW pigs,IUGR pigs had an increased alpha diversity of jejunum and ileum microbiota at 25 and 100 kg BWs(P<0.05).(2)IUGR altered the abundance of intestinal microbiota in growing-finishing pigs.Compared with the NBW pigs,at 25 kg BW,the abundance of several bacterial taxa such as Bacteroidetes,Lactobacillus,and unclassified Ruminococcaceae in the ileum of IUGR pigs increased(P<0.05).At 50 kg BW,the abundance of Firmicutes and Lactobacillus in the jejunum of IUGR pigs increased(P<0.05);while the abundance of several bacterial taxa such as Bacteroidetes,Proteobacteria,unclassified Ruminococcaceae,and Ochrobactrum in the jejunum of IUGR pigs decreased(P<0.05);the abundance of Lactobacillus in the ileum of IUGR pigs increased(P<0.05).At 100 kg BW,the abundance of Firmicutes and Lactobacillus in the jejunum of IUGR pigs increased(P<0.05).Experiment 3: The purpose of this study was to evaluate the effects of IUGR on the colonic microbial diversity and metabolites and mucosal antioxidant capacity of growingfinishing pigs.After slaughtering,the intestinal luminal contents and intestinal mucosa of the middle part of colon were collected and used for analysis of gut microbial 16 S rDNA sequencing.The results showed that:(1)IUGR affects colonic microbial diversity of growing-finishing pigs(P<0.05).The Simpson index of IUGR colonic microbiota was significantly higher than that of NBW pigs.At 50 kg BW,the colonic microbial community was obviously separated and aggregated into two groups.(2)IUGR altered the colonic microbial abundance at phylum and genus level of growing-finishing pigs.Compared with NBW pigs,Firmicutes abundance of IUGR pigs at 100 kg BW significantly increased(P<0.05).(3)IUGR decreased the content of colonic metabolites and improved the colonic antioxidant capacity of growing-finishing pigs.Compared with NBW pigs,the concentrations of resin amine in colon of IUGR pigs at 25 kg BW were significantly increased,while the concentrations of isobutyrate,butyrate,isovalerate,tryptamine,and the m RNA expression level of SOD1 in colonic mucosa were decreased(P<0.05);the colonic concentrations of butyrate,valerate,indoles,and putrescine in IUGR pigs decreased at 50 kg BW(P<0.05);the concentrations of acetate,isobutyrate,putrescine,cadaverine,and the m RNA level of SOD1 in IUGR pigs significantly decreased at 100 kg BW(P<0.05).In conclusion,IUGR decreased growth performance and impacted the development of organs,and lead to decrease ability of protein anabolism as well as nitrogen and lipid metabolism.Free amino acid metabolism,antioxidant capacity and colonic microbiota metabolites were impaired in the early stage,but recovered at the finishing stage of IUGR pigs.IUGR had no effect on colonic microbiota,but decreased the content of short chain fatty acids.Alterations in the abundances of Firmicutes,Proteobacteria,Ruminococcaceae,Lactobacillus,and Ochrobactrum in the small intestine may be associated with IUGR,and could therefore,be a future target for gut microbiota intervention in growing-finishing pigs subjected to IUGR.