| With the increasingly strict supervision on the use of antibiotics and the continuous improvement of public awareness at home and abroad,it has brought severe challenges to animal husbandry,and the development and application of antibiotic alternatives are imminent.Clostridium butyricum plays an important role in antibiotic alternatives due to its unique excellent characteristics.Clostridium butyricum is ubiquitous in soil and healthy animal feces.It is named Clostridium butyricum because it can produce organic acids with butyric acid as the main component.Clostridium butyricum was included in the China Feed Additives List(2013)in 2013.The purpose of this study was to investigate the optimal culture medium,culture conditions and effects of Clostridium butyricum on performance of chickens.The optimum culture medium for counting clostridium butyricum was selected by alternative medium,and the optimum culture conditions were set at different temperature and p H.To further identify Clostridium butyricum through physiological and biochemical tests,establish the detection method of Clostridium butyricum.To explore in broilers butyric acid bacteria in the digestive tract after engraftment and engraftment of poultry intestinal structure and performance,the influence of the choice of 30 healthy chicks,normal feeding to after 20 days of age were randomly divided into two groups,control group feed saline,experimental group irrigation under fluorescent tags,butyric acid bacteria dissect the epithelial cells of the ileum observing after 3 h;Another 20 healthy chicks were selected.The experimental group was fed with Clostridium butyricum for 1 to 6 days,and the control group was fed with clostridium butyricum for the whole period.At 16 and 21 days of age,the contents of short-chain fatty acids in ileum and cecum were collected for 16 S metagenomic analysis.The duodenum,jejunum and ileum of broilers at 21 days of age were observed and measured under a microscope.Clinical trials were carried out with 500g/t supplemental level for broilers and layers to observe the effects on poultry performance.The results are as follows:(1)The optimum culture medium for Clostridium butyricum was established as improved FTG medium,the optimum culture temperature was 37℃,and the optimum p H was7.0.(2)Through physiological and biochemical identification tests,clostridium butyricum gram-positive bacteria were found,and their bodies were rod-shaped or fusiform;All biochemical reactions were positive.PCR successfully amplified the target band and sequencing results showed that the DNA sequence and the known clostridium butyricum sequence homology reached more than 96%.(3)After the experimental group was fed with CLOstridium butyricum,there was a strong fluorescence phenomenon around the ileum epithelial cells,indicating that Clostridium butyricum can colonize in the intestinal tract of broilers.(4)Both in ileum and cecum,the content of short-chain fatty acids in experimental group was significantly higher than that in control group.(5)Through 16 S metagenomic testing,firmicutes were found to be the dominant flora in the 16-day-old samples,with the highest abundance.The important microorganisms in the experimental group were Blautia,and the important microorganisms in the control group were Clostridium and unclassified Trichospira.The microbial species in the 21-day-old samples increased,among which proteobacteria,Firmicutes and Bacteroidetes were the dominant flora with high abundance.The important microorganisms in the experimental group were Lactobacillus and Lactococcus,etc.,while the important microorganisms in the control group were Norcracidobacteria Gp4 and unclassified Trichomomonas,etc.,indicating that the beneficial bacteria in the intestinal tract of animals were increased after feeding clostridium butyricum.(6)Intestinal pathological test of broilers at 21 days of age showed that the villus height and crypt depth of jejunum in duodenum of experimental group were significantly higher than those of control group(P <0.05).Compared with the control group,the index of crypto ratio of twelve fingers in experimental group was significantly higher(P <0.05);These results suggest that Clostridium butyricum can promote the development of various intestinal tracts of broilers and enhance their absorption of nutrients in feed,which is beneficial to the growth and development of broilers.(7)When 500g/t clostridium butyricum was added in the whole diet,the broiler breeding rate increased by 0.8%,the market age advanced by 0.3 days,and the feed to meat ratio decreased by 0.022.Compared with the control group,the laying rate of the experimental group increased by 1.4%,the average egg weight increased by 0.8g/ egg,and the feed to egg ratio decreased by 0.06.In conclusion,this study found that the self-developed improved FTG culture medium could be used as the special culture medium for Clostridium butyricum,and the optimal growth condition was 37 ℃ and p H 7.0.In addition,the colonization of Clostridium butyricum in ileum epithelial cells of broilers increased the contents of short-chain fatty acids,microbial species,species abundance ratio,beneficial bacteria species,functional protein abundance,and chiller to hide ratio,thus promoting intestinal function and improving performance of broilers. |
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