Experimental Study On Of Improvement Tibial Cartilage Dysplasia By Total Flavonoids Of Rhizoma Drynariae In Broilers

Tibial Dyschondrodroplasa(TD)is a nutritional metabolic disease caused by the rapid growth of poultry.The clinical manifestations of TD were anorexia and decreased walking in the early stage.The clinical manifestations of TD were depression in the middle stage,with single leg or double leg lameness.In the late stage,with the deepening of the disease,the clinical manifestations were that the legs were unable to stand and the wings were used to replace walking.Severe cases died.The occurrence of TD has brought huge economic losses to broiler breeding industry.The global incidence of TD is as high as 30%.TD is one of the three difficult nutritional and metabolic diseases in broiler breeding industry.In recent years,people have been exploring drugs for the prevention and treatment of TD.Total flavonoids of Rhizoma Drynariae(TFRD)is extracted from the dry rhizome of Dryopteris crassipes,which has the function of changing articular chondrocytes,increasing the proliferation and differentiation of osteoblasts,inhibiting the maturation of osteoclasts and improving the degree of bone and joint lesions.Whether total flavonoids of Rhizoma Drynariae has therapeutic effect on tibial cartilage dysplasia in broilers was observed.A total of 240 1-day-old AA broilers were randomly divided into six treatments,including the control group(Con group,normal diet),the tibial cartilage dysplasia group(TD group,100 mg / kg thiram),the low-dose total flavonoids prevention group(LTFRD group,125 mg/ kg TFRD),and the low-dose total flavonoids treatment group(TD + LTFRD group,100 mg / kg thiram + 125 mg / kg TFRD).The middle-dose total flavonoids treatment group(TD+ MTFRD group,100 mg / kg thiram + 250 mg / kg TFRD),and the high-dose total flavonoids treatment group(TD + HTFRD group,100 mg / kg thiram + 500 mg / kg TFRD).The clinical symptoms and growth performance,TD incidence and mortality of broilers were recorded every day.The tibia index was measured by collecting samples,and the changes of organ index were weighed.The changes of growth plates were compared.The pathological sections of tibia growth plates were observed.The changes of OPG,RANKL,BMP-2 and Runx-2 gene expression were detected by fluorescence quantitative method.The changes of OPG and RANKL protein content were detected by Western blotting.The results showed that compared with the Con group,after the addition of thiram in the feed,the broiler showed poor mental state,loss of appetite,weight loss,and inability to stand and walk,and the TD model was successfully replicated.The weight of the LTFRD group was higher than that of the Con group,with good mental state,normal action and no abnormal state.Compared with the Con group,the TD group was unable to stand,showing split-fork style,depressed spirit,decreased food intake(p<0.05),and decreased body weight(p<0.05).After adding low,medium and high doses of total flavonoids of Rhizoma Drynariae,the feed intake increased significantly(p<0.05),the body weight of broilers increased gradually(p<0.05),and the broilers were in good condition and returned to upright walking.Tibial index results showed that the length and weight of tibia in LTFRD group were not significantly different from those in Con group(p<0.05).The length and weight of tibia in TD group were significantly lower than those in Con group(p<0.05).The growth plate width of TD group was wider than that of Con group((p<0.05);compared with the TD group,the width of tibial growth plate in the low,medium and high total flavonoids treatment groups recovered slowly on the 14 th and 21 st day(p<0.05).The histopathological results of broiler growth plate and broiler tibia showed that compared with the Con group,the longitudinal section of broiler growth plate in the TD group was white,and there was no vascular cartilage embolus.The width of the growth plate became thicker,and a large number of chondrocytes in the hypertrophic area of the growth plate died.In LTFRD group,the growth plate was normal,the blood vessels were rich,and the chondrocytes were in good condition.In TD + LTFRD group,TD + MTFRD group and TD + HTFRD group,the growth plate area began to recover on the 14 th day,and the width of the growth plate returned to normal on the 21 st day.A large number of new blood vessels appeared in the hypertrophic area of the growth plate,and the number of damaged chondrocytes decreased,especially in TD + HTFRD group.The number of blood vessels increased more,and the state of cells was better than that of TD + LTFRD group and TD + MTFRD group.The analysis of OPG,RANKL,BMP-2 and Runx-2 gene transcription levels showed that the gene content in LTFRD group was basically the same as that in Con group(p>0.05),Compared with the Con group,the OPG,BMP-2 and Runx-2 gene levels in the TD group on the 7th,14 th and 21 st days were significantly decreased(p<0.05)and the RANKL gene level was increased(p<0.05).Compared with TD group,the expression of OPG,BMP-2 and Runx-2 in TD + LTFRD group,TD + MTFRD group and TD + HTFRD group increased gradually at 14 days(p<0.05),and the expression of RANKL decreased at 14 days(p<0.05).Among them,the increase levels of OPG,BMP-2 and Runx-2 genes in the TD + HTFRD group were significantly higher than those in the TD + LTFRD group and the TD + MTFRD group(p<0.05),and the RANKL gene level in the TD + HTFRD group was significantly lower than that in the TD + LTFRD group and the TD + MTFRD group(p<0.05).After analyzing the protein expression of OPG and RANKL in the growth plate,it was found that compared with the Con group,the protein content of OPG in the LTFRD group was slightly higher than that in the Con group on the 7 th,14 th and 21 st day(p>0.05).There was no significant difference in the protein content of RANKL between the LTFRD group and the control group on the 7 th,14 th and 21 st day(p>0.05).The protein content of OPG in the TD group was lower than that in the Con group(p<0.05),and the protein content of RANKL was higher than that in the Con group(p<0.05).Compared with the TD group,the protein content of OPG in the TD + HTFRD group was higher than that in the TD group at day 14 and 21(p<0.05),and the protein content of RANKL was higher than that in the TD group at day 14 and 21(p<0.05).The results showed that the occurrence of TD could affect the growth plate of broiler tibia,resulting in cell differentiation disorder at the growth plate.500 mg/kg total flavonoids of Rhizoma Drynariae could improve the width of the growth plate of TD,and regulate the gene and protein levels of OPG,RANKL,BMP-2 and Runx-2,so as to alleviate the damage of TD on broilers.