Effects Of Lactobacillus Fermentum And Lactobacillu Paracasei On Growth Performance And Intestinal Health Of Broilers

In order to study the effects of Lactobacillus fermentum and Lactobacillus paracasei on growth performance,intestinal health of broilers co-infected by coccidia and Clostridium perfringens.A total of 336 1-day-old broilers(Ross 308)were randomly divided into 4 treatments with 6 replicates for each treatment and 14chickens in each replicate(7 males and 7 females).The four treatment groups were control group,coccidia and Clostridium.perfringens co-infection group,L.fermentum(1×10~9cfu/g)+infection group,L.paracasei(1×10~9cfu/g)+infection group.The trial period was 35 days.On the 9th day,the broilers needed to be infected were orally administered with coccidia vaccine with a dosage of 20 times,and the non infected broilers were inoculated with the same amount of normal saline.On the 13th day,the infected broilers were fed the feed mixed with C.perfringens liquid cultured for 20hours,which were eaten within 2 hours;Non infected broilers were directly fed the same volume of feed mixed with sterile meat culture medium without C.perfringens.Birds were fed continuously for 6 days.Fasting weights was recorded in the morning of the 13th and 19th days of the experiment,and then blood was collected from the vein under the wing and birds were slaughtered for sampling.1 Effect of Lactobacillus on growth performance of broilers with co-infectionOn d 1-13(day 1-13),compared with the control group,the feed weight ratio in infection group,L.fermentans+infection group and L.paracasei+infection group increased significantly(p<0.05);On d 14-19,compared with the control group,the average daily feed intake and average daily gain in the infection group,L.fermentans+infection group and L.paracasei+infection group decreased significantly,and the feed weight ratio increased significantly(p<0.05);Therefore,the mixed infection of coccidia and C.perfringens decreased the growth performance of broilers,and Lactobacillus had no significant effect on the growth performance of broilers.2 Effect of Lactobacillus on serum biochemical indexes of broilers with mixed infectionAt d 13,compared with the control group,the contents of GLU and HDL in the infection group decreased significantly,and the contents of Ca and ALT in the L.fermentans+infection group and L.paracasei+infection group increased significantly(p<0.05);Compared with the control group,AST contents in the infection group,L.fermentum+infection group and L.paracasei+infection group increased significantly(p<0.05).At d 19,compared with the control group,the contents of GLU,TG and ALB in the L.fermentum+infection group and L.paracasei+infection group decreased significantly(p<0.05);Compared with the control group,the contents of TC and HDL in the infection group,L.fermentans+infection group and L.paracasei+infection group decreased significantly,while the contents of ALT and UA increased significantly.Compared with the control group and the infection group,the contents of Ca and GGT in the L.paracasei+infection group were significantly higher(p<0.05).Therefore,infection with C.perfringens and coccidia will cause liver function damage in broilers.The addition of L.fermentans and L.paracasei will help to increase the content of calcium in serum.3 Effects of Lactobacillus on intestinal score and morphology of broilers with mixed infectionOn d 19,compared with the infection group,the score of jejunal and intestinal injury caused by C.perfringens infection was significantly reduced in the L.fermentum+infection group(p<0.05).Compared with the infected group,the effect of Lactobacillus in the diet on the villi height/recess depth of Broilers small intestine:d 13,the ratio of VH/CD of L.fermentans+infected group and L.paracasei+infected group increased significantly(p<0.05);d 19,the ratio of VH/CD of duodenum in L.paracasei+infection group was significantly increased,and the ratio of VH/CD of jejunum in L.fermentum+infection group and L.paracasei+infection group was significantly increased(p<0.05).Therefore,the mixed infection of coccidia and C.perfringens resulted in the morphological damage of small intestine in broilers.The addition of L.fermentans and L.paracasei was helpful to alleviate the morphological damage of small intestine.4 Effects of Lactobacillus on immune organ index and serum immune indexes in broilers with mixed infectionCompared with the control group,on d 13,the thymus organ index of L.fermentans and L.paracasei significantly decreased(p<0.05);On d 19,the spleen organ index of L.fermentans and L.paracasei increased significantly(p<0.05).Compared with the control group and the infection group,the i NOS content of L.fermentum+infection group and Lactobacillus paracasei+infection group increased significantly on d 13(p<0.05).Compared with the control group,on d 19,the lysozyme content in the infection group and Lactobacillus paracasei+infection group increased significantly(p<0.05).5 Effect of Lactobacillus on intestinal microorganisms in broilers with mixed infectionCompared with the infection group,on d 13,the number of coccidial eggs in ileum chyme and feces of the L.paracasei+infection group decreased significantly(p<0.05).On d 19,compared with the infection group,the relative number of E.coli in the L.paracasei+infection group decreased significantly(p<0.05).Conclusion:the mixed infection of coccidia and C.perfringens caused the decline of growth performance and intestinal injury in broilers;The addition of L.fermentum and L.paracasei can improve the intestinal morphology and structure after infection,thus alleviating the immune response and intestinal structure damage caused by infection.