Study On Bacillus Amyloliquefaciens Substituting As Antibiotics Replacement In Feeding Broilers

It has been suggested that the continuous use of antibiotics may cause a great deal of questions.Search for new material to subtitute antibiotic has become an important tusk with no effects on animal performance,health,and producer,s profit.The strain ES-2 was isolated from the Baikal skullcap root which belongs to Bacillu amytoliquefaciens.Bacillus amyloliquefaciens ES-2 is a potent Bacillus species that produces several extracellular enzymes and antifungal substance.The study was conducted to investigate the feasibility of Bacillus amyloliquefaciens ES-2 for application as a poultry dietary supplement.The effects of Bacillus amyloliquefaciens ES-2 on growth performance,carcass characteristics,meat quality,intestinal morphology and cecal microflora of broilerswere investigated.Its effects were compared with the experimental group fed with antibiotics.A total of 600 one-day-age broilers(Arbor Acres)were randomly assigned to five groups with 6 replicates.The control group were fed a basal diet without any probiotic and the antibiotic groups were fed the basic diet supplemented with 45 mg/kg chlortetracycline.The treatment groups(test ?????)were fed the basal diets supplemented with 200,500,1 000 mg/kg Bacillus amyloliquefaciens ES-2(with a final concentration 1.08×109 cfu/kg,2.70×109 cfu/kg,5.40×109 cfu/kg,respectively).Experimental diets were fed in two phases:starter(d 1 to 21)and finisher(d 22 to 42).The study includes four trials and general results are presentd as follow:Trial 1,the effects ofBacillus amyloliquefaeiens ES-2 on growth performance,carcass characteristics and organ indexes of broilers were investigated.The results showed that:(1)During the finisher phase and the overall experiment(d 1 to 42),addition of 500,1 000 mg/kg of B.amyloliquefaciens ES-2 significantly increased the average daily gain of broilers,decreased feed:gain ratio(P<0.05).The dose of 500 mg/kg displays the better production performance.(2)Compared with the control group,500,1 000 mg/kg of B.amyloliquefaciens ES-2 could significantly increase the percentage of breast muscle,and 500 mg/kg of B.amyloliquefaciens ES-2 decreased the percentage of abdominal fat(P<0.05).(3)Adding both 500 mg/kg of B.amyloliquefaciens ES-2 and antibiotic increased spleen index of 42 days old broilers(P<0.05).Trial 2,the effects of Bacillus amyloliquefaciens ES-2 on nutrient utilization,serum biochemical parameters and serum hormone levels in broilers were investigated.The results showed that:(1)Dietary supplementations with 500 mg/kg of B.amyloliquefaciens ES-2 improved the crude protein and Apparent metabolizable energy availability of 21 days old of broilers,improved the dry matter and crude protein availablity of 42 days old of broilers(P<0.05).(2)During the starter phase,Supplementation with 1 000 mg/kg of B.amyloliquefaciens ES-2 in diet very significantly improved the content of total protein(P<0.01);the addition of 500.1 000 mg/kg of B.amyloliquefaciens ES-2 and the antibiotic caused a significant decrease in triglyceride when compared with control group(P<0.01).(3)The serum levels of T4 was very significantly increased by adding both B.amyloliquefaciens ES-2 at dose of 500,1 000 mg/kg and the antibiotic(P<0.01)during the starter phase.On d 42,adding 1 000 mg/kg of B.amyloliquefaciens ES-2 increased the serum T4(P<0.05),it worked as well as antibiotic.Trial 3,the effects of Bacillus amyloliquefaciens ES-2 on intestinal morphology and cecal microflora of broilers were investigated.The results showed that:(1)No significant effect was observed on the relative length and relative weight of intestinal sections of 42 d broilers among all groups(P>0.05).(2)The villus height in duodenum was increased by adding B.amyloliquefaciens ES-2 at dose of 500,1 000 mg/kg(P<0.05);The villus height:crypt depth ratio in duodenum at the dose of 500 mg/kg was higher than the control group(P<0.01)?the dose of 200 mg/kg and the antiobiotic group(P<0.05).Adding 500 mg/kg B.amyloliquefaciens ES-2 decreased the crypt depth,increased the villus height:crypt depth ratio in jejunum(P<0.01),with the best effects being observed in group 500 mg/kg.The ileal villus height was increased by dietary 500 mg/kg of B.amyloliquefaciens ES-2 compared with the control group(P<0.05),meanwile,the villus height:crypt depth ratio in ileum at the dose of 500 mg/kg was higher than the dose of 1 000 mg/kg(P<0.05),and very significantly higher than other groups(P<0.01).(3)The population of the Lactobacillus was increased the in group 500?1 000 mg/kg when compared with both the control group and the antibiotic group(P<0.05);dietary B.amyloliquefaciens ES-2 resulted in decreased the Escherichia coli population in cecum(P<0.05).Trial 4,the effects of Bacillus amyloliquefaciens ES-2 on meat quality and antioxidative status of broilers were investigated.The results showed that:(1)Feeding with B.amyloliquefaciens ES-2 mainly affected breast muscle meat quality indices.Compared with the control group,the pH value of breast musle 24 hours after slaughter was significantly increased when B.amyloliquefaciens ES-2 was probvided at 500,1 000 mg/kg of diet(P<0.05).Broilers offered both 500 mg/kg of B.amyloliquefaciens ES-2 and antibiotic decreased pressure loss of breast muscle(P<0.05).(2)The activity of T-SOD of breast muscle was significantly increased by adding both B.amyloliquefaciens ES-2 at dose of 500,1 000 mg/kg and the antibiotic(P<0.05).In addtion,the T-AOC levels of the breast muscle were increased(P<0.05)when offered 500,1 000 mg/kg of B.amyloliquefaciens ES-2 to broilers,and the T-AOC levels of breast muscle at the dose of 500 mg/kg were higher than the dose of 200 mg/kg.In terms of the antioxidant capacity of the thigh muscle,providing both 500 mg/kg of B.amyloliquefaciens ES-2 and antibiotic could significantly increase the T-AOC levels(P<0.05),and the results was not different.The results of present study revealed that Bacillus amyloliquefaciens ES-2 can use as alternatives non-antibiotic feed additives to their free harmful side effects on the consumers and to improve broilers growth indices.Bacillus amloliquefaciens ES-2 could be a potential feed additive in broiler diets where 500-1 000 mg/kg(2.70×109-5.40×109 colony-forming units Bacillus amyloliquefaciens ES-2 per kg feed)showed the better efficiency.