| Chicken is a very important source of protein in human dietary structure and is favored by consumers for its high protein,low fat and relatively low price.However,the problem of feed mold caused by improper storage of feed ingredients has been plaguing the healthy development of poultry farming.Previous studies have reported that the problem of feed mold not only affects the health of poultry itself,but also threatens the quality of poultry meat.Aflatoxin B1(AFB1)is one of the most common foodborne mycotoxins causing feed mold,which may be produced during the production,storage and transportation of agricultural products,and is widely distributed and not easily removed.Chinese herbal medicine has been widely utilized as feed additives in broiler rearing process because of its pure natural,high efficiency and low toxicity characteristics.Among them,total flavonoids of Rhizoma Drynariae(TFRD),that are derived from the main components of the dried rhizome of Rhizoma drynariae,a traditional Chinese medicine,has various pharmacological activities such as immunomodulation,anti-inflammation and antioxidation,and may play a potential role in reducing AFB1 toxicity and improving muscle quality in poultry.Therefore,the present study focused on the toxic effects of AFB1 on meat quality in animal-derived foods and how TFRD could reduce the toxic effects of AFB1.One hundred and sixty 21-day-old AA broilers were randomly divided into control(CON group),aflatoxin B1 group(AFB1 group),total flavonoids of Rhizoma Drynariae group(TFRD group)and treatment group(AFB1+TFRD group)with four replicate cages per group and 10 chickens per replicate cage in a 7-day trial period.Study 1: Effect of AFB1 on the quality of broiler breast muscle and the therapeutic effect of TFRDAA broiler chickens at the age of 21 days were exposed to AFB1 at a dose of 50μg/kg body weight by crop injection and treated with 125 mg/kg of TFRD in the basal diet to observe the clinical symptoms and test the meat quality related indicators.The results are as follows:(1)After broilers were exposed to AFB1,the specific gravity of breast muscle in the AFB1 group was significantly higher than that in the CON group(p < 0.05).Quality parameters(e.g.,meat color,p H,drip loss)of breast muscle in the AFB1 group were changed,and a significant decrease in the L value of breast muscle meat color brightness occurred compared to the CON group(p < 0.05).p H of meat samples in the AFB1 group was significantly higher than that in the CON group after 24 h(p < 0.05).(p < 0.05),and drip loss in the AFB1 group was significantly higher compared to the TFRD group(p <0.05).(2)After broilers underwent AFB1 exposure,a significant increase in immobile water in the breast muscle was observed in the low-frequency MRI experimental CON group compared to the AFB1 group(p < 0.05),and a significant decrease in breast muscle texture(e.g.,hardness and flexibility)occurred in the AFB1 group compared to the control group in the textural analysis(p < 0.05)).(3)TFRD had a therapeutic effect to effectively restore the texture of the breast muscle and improve the quality of the breast muscle.A significant decrease in breast muscle flesh color b* value occurred in the TFRD group compared to the CON group(p <0.05),a significant increase in drip loss in the AFB1 group compared to the TFRD group(p < 0.05),and a significant increase in the textural analysis of meat samples in the TFRD group compared to the AFB1 group in terms of hardness,elasticity,hardness,elasticity,mastication,chewiness and recovery were significantly higher in the TFRD group compared to the AFB1 group(p < 0.05).Study 2: Metabolomics-based study of the effects of AFB1 and TFRD on metabolites in broiler breast muscleThe breast muscle samples of CON group,AFB1 group,TFRD group and AFB1+TFRD group were selected for metabolomics analysis,and all data analyses were based on the MWDB database built by Wuhan Metaville Biotechnology Co.PCA analysis,ternary analysis and KEGG enrichment analysis were performed on the identified metabolites.In addition,differential metabolites were screened and analyzed by Pearson correlation(Pearson)test to analyze the relationship between meat quality related parameters and differential metabolites among groups.(1)Metabolic analysis based on extensive targeted metabolomic techniques resulted in the detection of 762 metabolites.OPLS-DA analysis showed a significant separation of samples among the groups,and AFB1 caused serious interference in broiler breast muscle metabolism.(2)The results of KEGG enrichment analysis of metabolites that were significantly different between the test groups showed that broilers supplemented with AFB1 were enriched mainly in primary bile acid biosynthesis,lysine degradation,linoleic acid metabolism,cholesterol metabolism,and bile secretion.In addition,broilers supplemented with TFRD were mainly enriched in amino acid metabolism,energy metabolism and lipid metabolism.(3)breast muscle differential metabolites were strongly correlated with meat quality,with isoleucine-arginine and arginine-leucine positively correlated with meat colour-a*(p< 0.05).breast muscle p H was significantly positively correlated with isoleucine-arginine,arginine-leucine and alanine-tyrosine(p < 0.05).There was a significant positive correlation between shear strength and taurodeoxycholic acid(p < 0.05).(4)TFRD supplementation after broiler chickens underwent AFB1 exposure may affect the protein secondary structure of broiler breast muscle,and Raman spectroscopy detected an increase in the fibrous secondary structure of breast muscle,a significantly higher content of ɑ-helical structures in the AFB1 group compared to the AFB1 + TFRD group(p = 0.008).Study 3: Study of AFB1-induced oxidative damage to the breast muscle and the therapeutic effects of TFRD.To investigate the mechanism of the role of oxidative stress and inflammatory damage in AFB1 exposure-induced meat quality damage,broiler plasma was used for the detection of oxidative markers and antioxidant enzyme activities,and RT-q PCR was used to detect the expression levels of antioxidant and inflammatory factor-related genes in breast muscle tissue.Pearson correlation analysis was performed with metabolomic screening of differential metabolites to further explore the potential relationship between differential metabolites and oxidative inflammation related parameters.(1)After broilers underwent AFB1 exposure,oxidative stress and inflammation-related indicators changed.The addition of TFRD reversed the effects of AFB1 on broiler breast muscle inflammation and oxidative stress.Compared with the AFB1 group,the expression levels of SOD and CAT in the breast muscle of broilers in the AFB1 + TFRD group were significantly higher(p < 0.05),and compared with the AFB1 group,the AFB1 + TFRD group the m RNA expression of inflammatory factors IL-1β,IL-6,IL-10 and TNF-α was significantly decreased in the breast muscle of broiler chickens(p <0.05).(2)The occurrence of inflammation and oxidative stress in the breast muscle was closely associated with differential metabolites in the breast muscle,with plasma SOD activity showing a significant negative correlation with the α-helix in the protein secondary structure(p < 0.05),but m RNA expression of IL-6,IL-10 and TNF-α showed a significant and prominent positive correlation with the β-sheet protein secondary structure(p < 0.05).Meanwhile,m RNA expression of IL-6 and IL-10 showed a significant positive correlation with alanine-tyrosine(p < 0.05).Taken together,the results of this study suggest that AFB1 affects broiler breast muscle metabolite content through inhibition of inflammatory factor secretion and disruption of the antioxidant enzyme system,which in turn alters parameters related to breast muscle quality,including sensory and physical indices.In addition,metabolomic analysis screened several differential metabolites associated with oxidative stress,inflammatory damage and breast muscle quality,while Raman spectroscopy-based analysis revealed that AFB1 affected the secondary structure of myogenic fibronectin by altering breast muscle amino acid content.The addition of 125 mg/kg TFRD to the diet was found to be effective in restoring AFB1-induced changes in breast muscle metabolites and their myofibrillar protein secondary structure,reducing inflammation and oxidative damage,and thus improving breast meat quality. |
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