Effect of an Organic Trace Mineral Premix on the Semen Quality, Testicular Morphology and Gene Expression Related to Testosterone Synthesis of Male Broiler Breeders

In order to investigate the effect of organic trace minerals premix (OTM) on the reproductive performance of breeder roosters, a total of 240 San Huang roosters (23 weeks of age) were randomly divided into two treatments with six replicates of 20 roosters each. The first group (n = 120) was fed a basal diet containing an inorganic trace minerals premix (ITM) and the other group (n = 120) was fed the basal diet in which ITM was replaced by OTM. The experiment period was 22 weeks. Semen from one randomly-selected rooster per replicate was collected two weeks after the beginning of the experiment and other 10 times every two weeks. Another rooster per replicate was randomly selected at 30, 35, and 45 weeks of age, and sacrificed. Results showed that OTM did not affect relative organ weights. There was a significant increase in semen parameters in OTM group (p<0.05), such as semen volume, semen density, and semen motility from 31 to 35 weeks. OTM-fed roosters presented higher serum testosterone levels at 45 weeks of age, as well as higher testicular mRNA expression of the genes 3-beta dehydrogenase 2 (HSD3B2) and cytochrome P450 17A1 (CYP17A1) in the OTM-fed group at 45 weeks of age compared with those fed ITM (p<0.05). Considering the results of the present study, it was concluded that feeding organic instead of inorganic trace minerals to male broilers breeders improves semen quality, which may be attributed to their better testicular development and higher expression of enzymes related to testosterone synthesis.