H. Golshahi - Department of Pathology, Faculty of Veterinary Medicine, University of Tehran, Tehran,Iran
R. Sayrafi - Department of Pathobiology, Faculty of Veterinary Medicine, Amol University of Special Modern Technologies, Amol, Iran
A. Araghi - Department of Food Hygiene, Faculty of Veterinary Medicine, Amol University of Special Modern Technologies, Amol, Iran
M. Abouhosseini Tabari - Department of Pathobiology, Faculty of Veterinary Medicine, Amol University of Special Modern Technologies, Amol, Iran

This study aimed to investigate the effects of different doses of sulfadiazine on embryonic chicken pectoral muscles. In total, ۱۰۰ fertile eggs were obtained and divided into five groups of control (no injection) and sulfadiazine injection at doses of ۲, ۱۰, ۳۰, and ۷۰ 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 (۳۰ and ۷۰ 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 ۱۰, ۳۰ and ۷۰ 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 ۱۰ mg/kg of sulfadiazine is safe for chicken embryo, whereas dosage of ۳۰ mg/kg (or above) is considered highly toxic.

Sulfadiazine toxicity, Pectoral muscle, Chicken embryo