Effects Of Bacillus And Medium-chain Fatty Acids On The Growth Performance And Intestinal Development Of Weaned Piglets

The pre-weaning period is the most critical part of the piglet growing process.Piglets before and after weaning face changes in the production environment,nutrition,community struggles,and feeding management.The above-mentioned changes can lead to reduced feed intake and growth retardation in the piglets,and diarrhea and even death in the worst cases.This study explored the effects of Bacillus preparations and medium-chain fatty acids on the intestinal morphology and microflora of weaned piglets through three aspects,hoping to provide a reference and theoretical basis for weaned piglets without anti-resistant diets.This experiment was carried out in a certain type of pig farm in Shunyi district,Beijing.Three hundred and eighty-eight healthy 28-day-old weaned piglets with an average body weight of about7.5kg were selected for the experiment.The experiment adopted a single factor design.According to the principle of similar body weight and the same ratio of male and female,it was randomly divided into 4 treatments,each treatment had 10 replicates,each replicate 10 piglets,and each replicate was 1pen.Treatment 1 was the control group(basic diet),treatment 2 was the medium-chain fatty acid group(MCFA was added to the basal diet,and the content of the medium-chain fatty acid mixture was0.588 g/kg),and the treatment 3 was the Bacillus group(the Bacillus preparation was added to the basal diet,the number of viable bacillus was 1.3x10~9 CFU/kg),and treatment 4 were added both medium chain fatty acid and bacillus.The pre-test period is 5 days,and the trial period is 36 days.During the trial period,the feed intake was recorded every day,the piglets were weighed on an empty stomach before the morning feeding on the 1,10,and 37 days,and the diarrhea was recorded every day.On the 37th day,serum was collected from fasting jugular vein to determine antioxidant and biochemical indicators.Stool samples were collected from the 32-36 days of age for a digestion test to determine the apparent digestibility.After the feeding test,one piglet each replicate was selected for a slaughter test carried out on the 37th day to determine the morphological development of the small intestine(duodenum,jejunum,and ileum),colon VFA,and the contents of the jejunum and colon.Determine the intestinal microflora of jejunum and colon.The results showed that:in terms of growth performance and digestion performance:MCFA significantly improved the growth performance of weaned piglets(P<0.05),the feed-to-weight ratio was significantly reduced throughout the period(P<0.05),and the average number of antibiotics treated per day was significantly reduced(P<0.05).Compared with the CON group,the Bacillus group significantly increased the pre-BW(P<0.05),reduced the total diarrhea score and the average number of antibiotics per day(P<0.05).At the same time,the intestinal permeability was significantly reduced(P<0.01).the addition of both MCFA and Bacillus significantly improved the growth performance of weaned piglets,and significantly reduced the entire period of diarrhea and the average number of antibiotics per day(P<0.05).the MCFA,Bacillus and MCFA+Bacillus group have no significant effect on intestinal morphology,colonic TVFA and intestinal p H compared with CON group,but the content of colonic isobutyric acid and isovaleric acid were significantly higher than the CON group(P<0.05).In terms of microflora:The Bacillus group increased the diversity of colonic flora,and the abundance of the flora was significantly higher than that of other groups.There were significant differences in theβ-diversity of colonic contents among groups,and theβ-diversity of the MCFA and Bacillus group were significantly different(P<0.05).The relative abundance of Escherichia/Shigella in the jejunum of MCFA,Bacillus,and MCFA+Bacillus group was significantly lower than that in the control group,indicating that the proliferation of harmful bacteria was inhibited.To sum up,the results showed that adding MCFA or Bacillus to weaning diet can help piglets to cope with weaning stress and to improve growth performance and health by enhancing intestinal barrier and antioxidant capacity.The combination of Bacillus and MCFA has no synergistic effect on improving growth and intestinal health of piglets.