Histopathological changes and biochemical analysis of sulfadiazine injected in egg in chicken embryo pectoral muscles

This study aimed to investigate the effects of different doses of sulfadiazine on embryonic chicken pectoral muscles. In total, 100 fertile eggs were obtained and divided into five groups of control (no injection) and sulfadiazine injection at doses of 2, 10, 30, and 70 mg/kg. After hatching, pectoral muscle tissues were harvested from the newly hatched chickens for histopathological examination and measurement of oxidative stress parameters. Microscopic examination of pectoral muscle samples indicated that sulfadiazine administration changed the histopathological structure of chicken pectoral muscles only at very high doses (30 and 70 mg/kg). Major histopathologic events associated with sulfadiazine cytotoxicity were multifocal degeneration, necrotic tissue changes, and inflammatory cell infiltration (predominantly mononuclear cells) around degenerated and necrotic muscle fibers. Moreover, sulfadiazine at doses of 10, 30 and 70 mg/kg increased malondialdehyde level and decreased glutathione, ferric reducing antioxidant power, and total carotenoid, which indicated oxidative damage in broiler skeletal muscles. Therefore, it could be concluded that in-egg administration of up to 10 mg/kg of sulfadiazine is safe for chicken embryo, whereas dosage of 30 mg/kg (or above) is considered highly toxic.