Effects Of Seasonal Variation On Intestinal Microflora And Screening Of Intestinal Probiotic Bacillus In Free-range Luhua Chickens

Chicken intestinal flora and host present showed a nutritional interaction,and the changes in intestinal microbial structure and diversity affect Weight-gain and Egg-laying of Chickens.At present,the disadvantages of using antibiotics to regulate intestinal flora are expanding,probiotics as an effective substitute for antibiotics,lack of basis for use time,type,etc.This study studied the seasonal variation of intestinal flora of free-range Luhua chickens,guided the actual production and breeding,screened and identified intestinal probiotic Bacillus.The research contents are as follows.1.The structure of intestinal flora of Luhua chickens changed greatly with the season.The structure of cecum and small intestine in summer was only 66.7% and 62.5% similar to that in winter;the structure of intestinal flora changed significantly in summer,the proportion of dominant Lactobacillus in small intestine decreased significantly,and the number of Clostridium increased significantly;the richness of intestinal flora did not change significantly with the season,but the species and richness of small intestine flora are far less than that of cecum.2.According to the diversity index analysis,the diversity of cecum is obviously higher than that of small intestine;compared with the intestinal flora in spring,the environment in winter and summer will lead to the decrease of the diversity of cecum flora and the increase of the diversity of small intestine flora;as the main absorption site of nutrition,the flora fragrance index and evenness of small intestine are the lowest in spring when the environment is more suitable The number of species is small and the dominant bacteria account for a very high proportion.3.Lactobacillus,Bacteroides and Clostridium are the common cecum bacteria,while Lactobacillus is the main common small intestine bacteria.Common cecum bacteria have little change with season,and the proportion of different kinds of Lactobacillus in small intestine varies greatly with season.Specific Enterobacter spp.and Clostridium spp.increase in winter and summer,and more Lactobacillus spp.appear in spring.4.Six kinds of Bacillus were screened and identified from the intestinal tract of Luhua chicken.One of them was Lysinibacillus sphaericus,the other five were Bacillus mycosis,Bacillus licheniformis,Bacillus flexus,Bacillus cereus and Bacillus marcorestinctum.The results showed that seasonal changes had a significant effect on the diversity and structure of intestinal flora in free-range Luhua chickens,and the abundance and diversity of cecum flora were higher than those of small intestine flora.Seasonal variation regularity of intestinal flora in freely reared Luhua chickens: The proportion of Lactobacillus in intestine decreased in winter and summer,and the change of small intestine was most obvious in summer with more Clostridium increment;the diversity of cecum and small intestine flora showed opposite change regularity;in spring,the species of small intestine flora in freely reared Luhua chickens decreased,and the proportion of Lactobacillus was the highest.Bacillus also needs probiotics and safety identification for the development of microecol-ogical agents.