Study On The Effect Of Probiotics And Vegetable Carbon On Alternative Antibiotics On Broilers

After the ban of antibiotics in feeds,the selection of suitable antibiotic substitutes has become a heated issue for research.In this paper,three feed additives(Bacillus subtilis,Lactobacillus and biomass charcoal)were selected to explore their effectiveness in replacing antibiotics in broiler production.The experiments were performed on 240 Arbor Acres(AA)broilers(male and female mixed chicks)of similar body condition at 1 day of age,randomly divided into 5 groups with 6 replicates per treatment and 8 chicks per replicate.CON group(control group)was fed a basal diet.KS group was fed the basal diet supplemented with 300 mg/kg 20%aureomycin+300 mg/kg 20%salinomycin;KC group was fed the basal diet supplemented with 150mg/kg bacillus subtilis;LB group was fed the basal diet supplemented with 4×109 CFU/kg lactic acid bacteria;XF group added 0.05%vegetable carbon in basal diet.The experiment was conducted in two stages of feeding,the first stage(1～21 d)and the second stage(22～42 d),with free feeding and watering and no immunization throughout.The amount of feeds and leftovers were counted daily,and the broilers were weighed at 21 and 42 days of age to calculate the feed-to-weight ratio;at the same time,three chickens were taken from the lower wing vein in each replicate to determine the immune indexes;then slaughtered to determine the slaughter performance;intestinal samples were taken to observe the intestinal morphology,and cecum contents were taken to determine the cecum flora composition.The test results were as follows.In broiler production performance:slaughter performance.Compared with CON group,there were no significant differences in average daily feed intake and average daily gain of all treatment groups in the early stage(P>0.05),but the average daily gain of LB group was significantly higher than that of KC and XF groups(P<0.05),and the feed to gain of LB group was significantly decreased(P<0.05).At the later stage,the feed to gain ratio of LB group was significantly decreased(P<0.05);The average daily gain of LB,KS,KC and XF groups was significantly increased(P<0.05),and the average daily feed intake of KS and KC groups was significantly increased(P<0.05).Compared with CON group,leg muscle percentage was slightly increased and abdominal fat percentage was slightly decreased in all treatments,but there were no significant differences in slaughter performance indexes in all treatments(P>0.05).In immune organ index of broilers:compared with CON group,the immune organ indexes of KC group and LB group were significantly increased(P<0.05),spleen index and thymus index of XF group were significantly increased(P<0.05),spleen index and bursa of Fabricius index of KS group were significantly increased(P<0.05);At the later stage,the spleen index of KC group was significantly increased(P<0.05).In serum immune factors of broilers:compared with CON group,IgA and IgG contents in KC,LB and XF groups were significantly increased(P<0.05),IL-1 and IL6 contents in LB group and IL-2 contents in KC and XF groups were significantly increased(P<0.05),but there were no significant differences in all indexes in KS group(P>0.05).At the later stage,IgA content in KC,LB and XF groups and IgG content in KS,KC and XF groups were significantly increased(P>0.05).There were no significant differences in the contents of TNF-α,IgM,IL-1,IL-2 and IL-6 in the early stage and in the late stage among all treatment groups(P>0.05).Intestinal morphology of broilers:compared with CON group,villus height and villus to hide ratio of jejunum and caecum in each group were significantly increased in the early stage(P<0.01),and there was no significant difference among all groups(P>0.05).The ileum villus height in KS group was significantly increased(P<0.01),but no significant difference was found in LB,KC and XF groups(P>0.05).At the later stage,jejunum villus height was highly significant(P<0.01)in all treatments compared to the CON group and was significantly higher in the KS and XF groups than in the KC and LB groups(P<0.01).Compared with the CON group,the jejunum crypt depth in the XF group was highly significant(P<0.01),and the jejunum villi ratio in the KS and LB groups was highly significant(P<0.01),while there was no significant difference in the KC and XF groups(P>0.05);the ileum villi height in the KS,KC,and XF groups were all highly significant(P<0.01),and the KS group was highly significant higher than the KC and XF groups(P<0.01).The ileum crypt depth in the KC and LB groups had a highly significant decrease(P<0.01),and the ileum villi ratio in the KS and KC groups had a highly significant increase(P<0.01)and the KC group was significantly higher than the KS group(P<0.01).Cecum villi height in the KS,KC,and XF groups had a highly significant increase(P<0.01)compared to the CON group and there was no significant difference between them(P>0.05).In cecal micro flora of broilers:compared with CON group,the Chao index,Ace index and Shannon index of each treatment were increased,while the Simpson index was decreased,and the relative abundance of some bacteria at phylum or genus level was increased.Conclusion:The three additives,Bacillus subtilis,Lactic acid bacteria,and biomass carbon,can improve the production performance of broilers,have no significant improvement on slaughter performance,enhance the immune function of broilers,promote the morphological development of the intestinal tract,regulate the intestinal flora,increase the abundance and species diversity of the intestinal probiotic community of broilers,maintain the stability of the intestinal flora and can play a role in replacing antibiotics.