Effects Of Androgen On Cardiovascular Function Of Broilers

Sudden death syndrome (SDS) is one of the three major nutritional and metabolic diseases in broilers. And the lethality of SDS is the most, which causes a lot of losses in economy. Previous studies had shown that SDS was a cardiac disease, which might be associated with the changes in cardiac structure and function. There was a clear gender differences in susceptibility to SDS and cardiovascular function in broiler, indicating that different sex hormones might be the main reason which caused the gender differences in cardiovascular function in broilers. The effects of androgen on cardiovascular function in mammalian had been carried out in previous studies, but the results remained controversy. The role of androgen in cardiovascular function of broilers had not been reported; therefore the present study attempted to carry out an exploratory research on this area. The contents of this study were as follows:1.120 male broilers were orchidectomized or sham operated at 7 day-old. Ten days later, two groups of orchidectomized broilers were supplemented with testosterone propionate (TP) and supplemented with flutamide followed by TP respectively. ECG was monitored, and serum enzymes activities, lipids levels, electrolytes levels, and ventricular vulnerability were detected at 28 day-old. After that morphology of heart including cardiac index and histological structure were performed. mRNA level of genes encoding androgen receptor(AR), the transforming growth factor-β2 (TGF-β2) and its two types of receptor were detected in the cardiac tissues by real-time RT-PCR.2. Androgen replacement prevented the heart rate, serum aspartate amino transferase(AST), lactate dehydrogenase(LDH) activities, high density lipoprotein-cholesterol(HDL-C) and serum calcium level from increasing by orchidectomy. There was no effect of androgen on ventricular vulnerability and morphology of heart. Orchidectomy and TP treatment could reduce the mRNA level of cardiac AR. Androgen could down-regulate the expression of TGF-β32. The effect of androgen was partly attenuated after AR was blocked. 3. Conclusion:androgen compensation might partly avoid the changes causing by orchidectomy in the heart rate, serum enzymes, lipid levels, blood calcium concentration and TGF-P of broilers, which indicated that androgen could play a benefit role in cardiovascular system of broiler. However, whether AR mediated the effects of androgen had not yet been fully confirmed.