The Effects Of New Functional Compound Lactic Acid Bacteria On Prevention Of African Swine Fever Infection In Piglets Were Evaluated Based On Growth Performance Indexes

ASF has spread rapidly since it was first reported in China in August 2018,with nearly200 cases reported across 32 provinces,a mortality rate of 100 percent,the culling of millions of pigs and direct economic losses of tens of billions of dollars.Despite the emergence of ASF nearly 100 years ago,there is no effective vaccine to date,relying mainly on detection and culling strategies while requiring strict biosafety controls.During the surveillance of African swine fever(ASF),it was found that probiotics added to feed and fermentation bed rarely occurred African swine fever.We speculated that probiotics might block the infection of African swine fever virus(ASFV)by affecting the structural diversity of intestinal flora of pigs.Based on this research in the National Natural Science Foundation of African Swine Fever special fund.The following studies were carried out with funding from "Basic Research on African Swine Fever virus Blocking technology and Biological Prevention and control".The new functional compound lactic acid bacteria constructed by the research group were orally fed to weaned piglets,and fed every other day for 7 times in total for 14 days.Piglets were challenged after resting for 3 days,and the effects of new functional compound lactic acid bacteria on the production performance of weaned piglets were observed and measured.The results were as follows: the total feed intake of each piglets in the compound lactic acid bacteria group was significantly different from that in the PBS group(P < 0.001),and the total feed intake of the compound lactic acid bacteria group was significantly different from that in the healthy group(P < 0.001).The average daily gain of piglets in compound lactic acid bacteria group was significantly higher than that in PBS group and healthy group(P <0.01).The feed to meat ratio of compound lactic acid bacteria group was significantly different from that of healthy group(P < 0.01).Diarrhea rate analysis of piglets showed that no diarrhea occurred after feeding compound lactic acid bacteria,and the difference between compound lactic acid bacteria group and PBS group was extremely significant(P < 0.001).After weaning,piglets in each group had a small amount of diarrhea,and the feces of piglets fed with compound lactic acid bacteria gradually improved from sticky unformed to wet formed,and remained there all the time.The feces of piglets in PBS group and healthy group were between gruel-like diarrhea and sticky-like unformed line for a long time.Statistical analysis of body length and abdominal circumference of weaned piglets in each group showed that there was no significant difference in body length between 0 and 7 days in the compound lactic acid bacteria group.At14 days,the body length of piglets in compound lactobacillus group was significantly higher than that in PBS group and healthy group(P<0.01).The abdominal girth of piglets in compound lactic acid bacteria group was significantly higher than that in PBS group and healthy group.The diarrhea rate in PBS group was significantly higher than that in compound lactic acid bacteria group and healthy group(P<0.01).The daily gain in compound lactobacillus group was significantly higher than that in PBS group(P<0.05),and the daily gain in healthy group was significantly higher than that in PBS group(P<0.01).The heart index and liver index of piglets in compound lactobacillus group were significantly different from those in PBS group(P<0.05).Spleen index and kidney index of compound lactic acid bacteria group were significantly different from those of PBS group(P<0.05).When the viscera index increases,it indicates that the viscera appear local congestion or edema and other lesions;When the viscera index decreases,it indicates partial atrophy and other attenuating changes of viscera.There was no significant difference between the compound lactic acid bacteria group and the healthy group,indicating that the spleen injury degree of the experimental group was lower and closer to the normal pigs.Compared with PBS group,the body length and abdominal circumference of piglets combined with lactic acid bacteria were significantly increased(P<0.01).After the dissection of weaned piglets in each group,the intestinal tract of each group was compared.Diffuse bleeding,swelling,color flushing and other lesions in the intestinal tissues of piglets in THE PBS group were compared with those in the compound lactic acid bacteria group,and the lesions in the compound lactic acid bacteria group were more healthy than those in the healthy group.Under the scanning electron microscope of 200 um,the surface of duodenal villi in PBS group was rough,and there were more mucus and impurities in the villi space,while there were less in the compound lactic acid bacteria group and healthy group.Under the 30 um field of vision,there were more holes in the villi surface of PBS group,while the smooth surface of the compound lactic acid bacteria group and the healthy group affected the nutrient digestion and absorption of piglets.Compared with PBS control group,duodenum and villus height in compound lactic acid bacteria group were significantly higher than those in PBS group and healthy group(P<0.05).The crypt depth of duodenum in compound lactic acid bacteria group was significantly lower than that in PBS group(P<0.05),and the ratio of villus height to crypt depth in compound lactic acid bacteria group was significantly higher than that in PBS group and healthy group(P<0.01).The jejunum villus height in compound lactobacillus group was significantly higher than that in PBS group(P<0.05).The jejunum crypt depth in compound lactobacillus group was significantly lower than that in PBS group(P<0.05),and the ratio of villus height to crypt depth in compound lactobacillus group was significantly higher than that in PBS group and healthy group(P<0.001).The villus height of ileum in compound lactobacillus group was significantly higher than that in PBS group and healthy group(P<0.05).In crypt depth statistics,the ileum crypt depth of the compound lactobacillus group was significantly lower than that of the PBS group(P<0.001),and the ratio of villus height to crypt depth of the compound lactobacillus group was significantly higher than that of the PBS group and the healthy group(P<0.01).Of compound lactic acid bacteria are weaned piglets production performance and production performance after infection,the influence of unknown compound lactic acid bacteria could promote the growth of piglets,especially against poison after new functional composite could prevent piglets temperature by lactic acid bacteria,the result is a new functional probiotics to prevent African swine fever provides an important reference.