Screening Of Clostridium Butyricum And Its Effects On Animal Antioxidation And Meat Quality In Broiler Chickens

This study was performed to screen Clostridium butyricum from animal intestines and determine its effects on animal antioxidation and meat quality in broiler chickens as well as its underlying mechanism.Expt.1was conducted to isolate and screen C. butyricum with excellent biological properties and stress resistance from different animal intestines or feces.16strains of similarity with C. butyricum more than99%were identified by16S rDNA after obtaining strains by reinforced clostridial medium and tryptone sulfite neomycin medium as well as spore and strictly anaerobic conditions. These stains were first screened by comparing their butyric acid and total short-chain fatty acid (SCFA) production and5strains with better producing acid ability were chosen to identify by API-20A and specific molecular identification. Then the C. butyricum strains were screened by comparing their activity of amylase and cellulase, viable count of the strains, spore viability, viability of simulated gastric fluid and simulated intestinal fluid. Finally, one strain of C. butyricum with the best biological property and stress resistance was chosen for the following experiment, and this strain of C. butyricum could produce superoxide dismutase (SOD) and NADH oxidase as well as H2and CO2gases.Expt.2was performed to investigate the effects of C. butyricum on antioxidation and serum lipid in oxidative stressed mice induced by corticosterone (CORT) administration (20mg CORT/kg body weight).75SPF-class KM male mice (about20g) were divided into5groups with five replicates for14d:blank control group, oxidative stressed group, oxidative stress+1×105,1×106and1×107CFU C. butyricum. Corticosterone was dissolved in olive oil and C. butyricum was dilluted into different doses with physiological saline. The results showed that supplementation of C. butyricum alleviated the decrease of glutathione S-transferase (GST) activity and glutathione (GSH) content and the increase of malondialdehyde (MDA) content of liver in oxidative stressed mice. C. butyricum increased SOD and GST activities as well as GSH concentration while decreased MDA content of colon mucosa in mice. Moreover, C. butyricum reduced cholesterol and high-density lipoprotein cholesterol concentrations of serum in mice.Expt.3was conducted to investigate the effects of C. butyricum on growth performance, intestinal health, immune function, antioxidation and meat quality of broilers.3201-d-old Arbor Acres commercial male chicks were randomly assigned to one of five treatments with eight replicates in a completely randomized design for42d. The birds were randomly divided into five treatments:the basal diet (control),2.5×108CFU C. butyricum/kg,5×108CFU C. butyricum/kg,1×109CFU C. butyricum/kg, and150mg of aureomycin/kg (antibiotic). The results showed that supplementation of C. butyricum increased average daily gain during d1to21and d22to42, improved duodenal morphology at21and42d of age and increased acetic acid, butyric acid and total SCFA concentrations of cecal digesta at21d of age, promoted IgM concentration of serum at21and42d of age, improved antioxidant status of duodenal, jejunum and ileum mucosa, serum and liver at21and42d of age, increased breast muscle percentage and decreased ablominal fat percentage at42d of age, inceased polyunsaturated fatty acid (PUFA) C20:2n-6, C20:3n-6, C20:3n-3, C20:4n-6(ARA), C20:5n-3(EPA), C22:6n-3(DHA) and total PUFA concentrations as well as PUFA/SFA (saturated fatty acid) ratio of breast muscle at42d of age, inceased PUFA C18:2t-9t-12, C20:3n-6, C20:3n-3and EPA concentrations of thigh muscle at42d of age, but did not affect most of SFA and monounsaturated fatty acid (MUFA) of breast and thigh meat, and decreased cholesterol and high-density lipoprotein cholesterol contents of serum at21d of age and cholesterol content of serum at42d of age. The results indicate that the improved meat quality of broilers fed a diet supplemented with C. butyricum may be as a result of the enhancement of antioxidant defenses, intestinal health and immune function.Expt.4was conducted to evaluate the effects of butyrate on cellular antioxidation and viabiltiy. In this study, we examined the effects of butyrate on cell viability, mitochondrial superoxide generation and GSH redox potentials, gene expression of glutamate-cysteine ligase modifier (GCLM) and catalytic (GCLC) subunits as well as glutathione reductase (GSR), GSR activity, nuclear histone deacetylase (HDAC) and nuclear factor erythroid2(NFE2)-related factor2(Nrf2) activities in HCT116colorectal cancer cells. The results showed that a low concentration of butyrate (0.5mM) significantly increased the expression of GSR and GCLM while the opposite was observed with a relatively high butyrate concentration (5mM). Moreover,0.5mM butyrate slightly reduced while5.0mM butyrate potentiated antimycin A-induced oxidative injury, which was regulated by the Nrf2-antioxidant response element (ARE) pathway.In conclusion, C. butyricum was obtained from different animal intestines or feces by specific methods in the current study; the effects of C. butyricum on improving antioxidation and decreasing serum lipid were approved in oxidative stressed mice; the results of broiler experiment indicate that the improved meat quality of broilers fed a diet supplemented with C. butyricum may be as a result of the enhancement of antioxidant defenses, intestinal health and immune function; and finally it was found that the effects of butyrate on cellular antioxidation and viabiltiy may be regulated by the Nrf2-ARE pathway.