The Study On The In Vitro Bacterial Inhibiting Ability Of Turmericextract-compound And Fructus Crataegi Extract And Their Application Effect On Performance Of 57～85-day-old Mahuang Broilers

In this study,7 species of animal pathogenic gram-negative bacteria,i.e.,Aeromonas hydrophila,Pseudomonas aeruginosa,Edwardsiella tarda,Salmonella pullorum,Salmonella cholerae,Escherichia coli K88 and Actinobacillus pleuropneumoniae and 4 species of animal pathogenic gram-positive bacteria,i.e.,Staphylococcus aureus,Streptococcus Agaricus,Clostridium perfringens type A and Streptococcus suis were selected as the indicator bacteria to carry out bacteriostatic test in vitro for five plant extracts,i.e.,Pericarpium Granati Extract(PGE),Galla Chinensis Extract(GCE),Fructus Crataegi Extract(FCE),Herba Houttuyniae Extract(HHE),and Rhizoma Curcumae Longae Extract(RCLE),to determine their Minimum Inhibitory Concentration(MIC)and Minimum Bactericidal Concentration(MBC).PGE,GCE,HHE and RCLE were formulated to make the plant extract compound called Turmeric Extract Compound(TEC),and the MIC and MBC of TEC were further determined.Then,TEC(at 0 and 30 g/t)and FCE(at 0,50,100,200,400 g/t)were used as two testing factors to carry out a feed experiment on 57-day-old Mahuang broilers for four weeks.In the feeding experiment,1020 56-day-old Mahuang male chicks were randomly divided into 10 treatments with 3 replicates of 34 each,and fed 10 experimental diets(T0F0,T0F50,T0F100,T0F200,T0F400;T30F0,T30F50,T30F100,T30F200 and T30F400)respectively for 4 weeks.The former 5 diets were the basal diet supplemented with TEC at 0 g/t and FCE at 0,50,100,200 and 400 g/t respectively.The later 5 diets were the basal diet supplemented with TEC at 30 g/t and FCE at 0,50,100,200 and 400 g/t respectively.At the end of the feeding experiment,3 chickens were selected from the control group T0F0 and several groups with the best growth performance respectively to obtain serum samples and cecum content samples for the determination of biochemical indicators of serum and the number of E.coli,Lactobacillus,total aerobic bacteria and Bacillus in cecum digesta.The result showed that:(1)PGE,GCE,HHE,RCLE,and FCE showed certain inhibitory effects against the above 11 strains of bacteria with their average MIC/MBC being 11.4/13.4,33.2/33.2,163.6/163.6,202.6/206.8,23.9/23.9 and 90.9/116.5 respectively,the order of their bacteriostasis being PGE >TEC > GCE > FCE > HHE > RCLE.PGE,GCE,HHE and RCLE showed no antagonistic effects on the inhibition of the 11 animal pathogens.(2)TEC(at 0 and 30 g/t)had no significant effect on Average Daily Feed Intake(ADFI),Average Daily Gain(ADG)and F/G ratio,but FCE(at 0,50,100,200 and 400 g/t)had significant effect on ADFI,ADG and F/G of the birds.There was interaction effect between TEC and FCE on ADFI,ADG and F/G,with the optimum supplementation dose being FCE at 200 g/t or TEC at 30 g/t plus FCE at 100 g/t.(3)The supplementation of FCE at 200 g/t or TEC at 30 g/t plus FCE at 100 g/t enhanced the level of serum total protein and lipopolysaccharides of broilers,decreased the E.coil count and increased the ratio of Lactobacillus count to E.coil count in caecum digesta.