Comparetive Study Of Three-phase And Five-phase Feeding Programs On Immune Function,gut Health And Intestinal Microflora In Growing-finishing Pig

The large-scale pig farms in China generally adapt three-phase feeding program,but due to too few phase divisions,it cannot fully meet their nutritional requirements,which may cause insufficient nutrition or excessive nutritionsupply,and limit the optimal growth performance of pigs.therefore,more and more scholars pay attention to multi-phase feeding.However,there are few reports of studies on five-phase feeding.Therefore,this experiment explores the effects of the five-phase feedingprogram on growth performance,immune function,and intestinal health of growing-finishing pigs on the basis of the three-phase feeding commonly used.the effects of the five-phase feeding program on intestinal microflora and plasma metabolites of growing-finishing pigs were analyzed by 16 Sr RNA sequencing and plasma metabolomics,which canprovide theoretical basis for theapplication of the five-phase feedingprogramin sustainable pig production.Experiment 1: The effects of three-phase and five-phase feeding programs on growth performance,immune function and intestinal health of growing-finishing pigs.a total of 240 eighty-day-old healthy Landrace-Large growing-finishing pigs with similar body weight were randomly divided into 2 groups with 8 replicates per group and 15 pigs per replicate.The control group adopted the three-phase feeding program commonly used in pig farms,The test group adopted five-phase feedingprogram,The trial period lasted for 100 days.The main results were as follows:(1)In the whole feeding process,compared with the three-phase group,There was no significant difference in the ADG,ADFI,F/G,crude protein intake per unit weight(g/kg)of the five-phasegroup on growing-finishing pigs(P>0.05).However,under the premise of not affecting the normal growth performance,F/G,crude protein intake per unit weight(g/kg)had aslightdecreased trend.(2)There was no significant difference in organ index and intestinal contents p H between the two feeding programs(P>0.05);Compared with the three-phase group,the five-phase group can significantly increase the serum Ig M level(P<0.01),and it had a tendency to increase the serum Ig A,Ig G levels and s Ig A content in the jejunumtissue.The levels of serum IL-1?,TNF-?,IL-6 and IL-1?,TNF-? and IL-6 m RNA in colon tissues were lower than the three-phase group,while the levels of IL-10 and IL-10 m RNA were higher than that in the three-phase group,but the differences was not significant(P>0.05).(3)There was no significant difference in serum endotoxin,D-lactic acid and the concentration of SCFAs in colon contents between the two feeding programs;and the content of SOD,GSH-PX,and T-AOC in the jejunum tissue of the five-phase group were higher than that in the three-phase group,while the MDA content was lower than the three-phase group,but the differences was not significant(P>0.05).On this basis,fluorescent quantitative PCR was used to further detect the expression of antioxidant-related genes m RNA level,The results showed that compared with the three-phase group,the five-phase group can significantly increase the expression levels of Nrf2 and NQO1 m RNA(P<0.05),and increase the expression levels of CAT1,GSH-PX1,SOD1,SOD2,SOD3,HMOX-1 m RNA,While decreased the expression level of KEAP1 m RNA,but the differences was not significant(P>0.05).Experiment 2: The effects of three-phase and five-phase feeding program on the intestinal microflora and plasma metabolites of growing-finishing pigs.The main results were as follows:(1)16Sr RNA sequencing revealed that a total of 2224 OTUs were produced at155 d,the two groups identical OTUs were 1605,and a total of 2093 OTUs were produced at 180 d,the two groups identical OTUs were 1596.at 155 d and 180 d,there was no significant difference in the Alpha diversity between the two groups(P>0.05),but based on the weighted Uni Frac distance analysis,the cluster tree of species composition between samples found that the clustering condition was better at 155 d,and the clustering effect at 180 d was not as obvious as that of 155 d,indicating that the same feed was used over time,species composition between the two groups may show a certain degree of convergence.(2)At phylum level,the relative abundance of intestinal bacteria was not significantly different(P>0.05).but at 155 d,further analysis at family,genus,andspecies levels found that the relativeabundances of Lactobacillaceae family,Lacobacillus genus,and Lactobacillus?salivariusin five-phase group was significantly higher than in three-phase group(P<0.05).while at 180 d,The relative abundances of these intestinal bacteria in five-phase group was still higher than in three-phase group,but the difference was not significant(P>0.05).(3)A total of 592 differentially significant metabolites were screenedat 155 d by non-targeted metabolomics analysis,while at 180 d,a total of 345 differentially significant metabolites were screened.At 155 d,the enrichment analysis of the metabolic pathways of differential metabolites found that the five-phase feeding program mainly affected amino acid metabolism,Gn RH signaling pathway,steroid hormone biosynthesis,citrate cycle(TCA cycle),mineral absorption,Fc gamma R-mediated phagocytosisand other metabolic pathways.While at180 d,it mainly affects amino acid metabolism,Gn RH signaling pathway,taurine and hypotaurine metabolism,Fox O signaling pathway,Fc gamma R-mediated phagocytosisand other metabolic pathways.In summary:(1)The five-phase feeding program does not affect the normal growth performance,may improve the immune function of growing-finishing pigs,regulates the antioxidant capacity of jejunal tissue through the Nrf2-Keap1 signaling pathway.(2)The five-phase feeding program can significantly increase the relative abundance of Lactobacillaceae family,Lactobacillus genus and Lactobacillus?salivarius at 155 d,while at 180 d,the relative abundance of streptococcus?alactolyticus was significantly reduced in the five-phase feeding program.(3)Compared with the three-phasefeeding program,at 155 d and 180 d,the five-phase feeding program mainly affected amino acid metabolism,Gn RH signaling pathway,Fc gamma R-mediated phagocytosis and other metabolic pathways in growing-finishing pigs.