Effects Of Acidifiers On Growth Performance,Immunity,Antioxidant Capacity And Gut Microbiota Of Weaned Piglets

Early weaned piglets are exposed to multiple stressors such as psychological,nutritional and environmental,which can lead to growth retardation,diarrhea and high mortality in weaned piglets.At present,antibiotics have been completely banned in feed,and the primary task of animal husbandry is to develop safely,environmentally friendly and efficient alternatives to antibiotics.Acidifiers can improve the growth performance of piglets,which is mainly related to decrease the digesta p H values and pathogenic bacteria and maintaining the balance of microflora,and have very broad application prospect in production.The objective of the current study was to evaluate the effects of the two acidifier on the weanling piglets’ growth performance and the intestinal health status.A total of 360 twenty-one-days-old Pig Improvement Company(PIC)weanling pigs(5.3 ±0.6 kg)were randomly allotted into 3 dietary treatment groups with 12 replicates of 10 pigs/pen.The weaned piglets in the three treatment groups were fed the same basic diet.And the control group was fed tap water,and the two treatment groups were fed tap water with 2.0 L/Ton acidifiers OA1 and OA2 with different compositions,respectively.The whole trial period lasted for 49 days.On the 14 th and 49 th days of the trial period,six male piglets with similar weight were randomly selected from each group for slaughter sampling.The effects of acidifier on the growth performance,intestinal morphology,serum biochemical and antioxidant indexes,jejunum-related gene expression and cecal flora of weaned piglets were measured and analyzed.The main test results were as follows:1.Effects of acidifier on the growth performance: compared to the control,acidifier OA1 significantly increased(P < 0.05)feed intake and body weight gain of weaned piglets during days 1-14,and increased(P = 0.09)body weight gain during days 1-49.Acidifier OA2 significantly reduced(P < 0.05)the diarrhea rate in piglets from 15-49 days.In addition,there was no difference(P > 0.05)in mortality between the whole experimental study.2.Effect of acidifier on antioxidant capacity of weaned piglets: On the 14 th day of the experiment,acidifiers OA1 tended to increased(P = 0.09)the activity of serum CAT,acidifier OA2 significantly increased(P < 0.05)the activity of serum T-AOC in piglets.On the 49 th day of the experiment,acidifiers OA2 tended to increased(P = 0.09)T-AOC activities.Meanwhile,acidifiers OA1 and OA2 significantly increased(P < 0.05)the activity of SOD in piglet serum,and significantly decreased(P < 0.05)serum MDA content.3.Effects of acidifier on intestinal health of weaned piglets: The results of intestinal histomorphology showed that villi of ileum(14th day)and jejunum(49th day)in control group were broken,and epithelial cells were slightly vacuolated,but no such pathological changes were found in the intestines of OA1 and OA2 groups.In addition,on the 49 th day of experiment,Notably,the intestinal morphology results showed that acidifiers OA2 significantly increased(P < 0.05)the ratio of villus height: crypt depth in duodenum than those of the control and OA1.Notably,the intestinal morphology results showed that acidifiers OA2 tended to decrease(P = 0.09)the crypt depth and tended to increased(P =0.07)the ratio of villus height: crypt depth in duodenum of piglets at day 49 than those of the control and OA1.4.Effects of acidifiers on genes related to cytokines,tight junctions and host defense peptides in piglets:On the 14 th day of the experiment,acidifiers OA1 and OA2 significantly increased(P < 0.05)the expression levels of defense peptides PBD1,PBD2,NPG1 and NPG3 genes in the jejunum of weaned piglets,and only acidifier OA2 significantly decreased(P < 0.05)interleukin(IL-1β and IL-2)gene expression,and significantly increased(P < 0.05)the expression of piglet jejunal tight junction protein(claudin-1)On the 49 th day of the experiment,the acidifier OA2 significantly increased(P < 0.05)the expression of PBD2 and NPG3 genes in the jejunum of piglets.5.Effect of acidifier on intestinal microbial homeostasis of weaned piglets : On the14 th day of the experiment,acidifier OA1 significantly reduced(P < 0.05)abundance comparisons of predominant genera revealed that Dorea,Coprococcus,and Eubacterium in piglet intestinal tract,while Subdoligranulum and Coprococcus in OA2 group significantly decreased(P < 0.05)when compared to the control.On the 49 th day of the experiment,Coprococcus and Blautia in OA1 group,Blautia and Bulleidia in OA2 group increased significantly(P < 0.05),while YRC22 was significantly decreased(P < 0.05)in OA1 and OA2 when compared to the control.In conclusion,both acidifiers OA1 and OA2 can improve the performance and health of weaned piglets by modulating redox homeostasis,immunity and microflora in the piglet gut.