Pathophysiological Consequences of Antibiotic Administration on Muscle Tissue Development in Broiler Chickens

The extensive application of antibiotics in commercial broiler production has raised growing concerns regarding their measurable pathophysiological effects on muscle tissue development. In this study, the pathophysiological consequences of prolonged antibiotic administration on skeletal muscle growth in broiler chickens were evaluated under controlled production-like conditions. A total of ۴۰ one-day-old broiler chicks (Ross ۳۰۸) were randomly assigned to a control group (n = ۲۰) and an antibiotic-treated group (n = ۲۰). Birds in the treatment group received a commonly used commercial antibiotic premix containing oxytetracycline (۵۰ mg/kg feed) and enrofloxacin (۱۰ mg/L drinking water) for ۴۲ consecutive days, mimicking common farm practices. At the end of the trial, tissue samples from the pectoralis major and biceps femoris muscles were collected for histological and morphometric analysis. Histological examination revealed notable structural alterations in the antibiotic-treated group, including: a ۱۲-۱۸% reduction in mean muscle fiber diameter, mild to moderate myofiber degeneration, inflammatory cell infiltration quantified at approximately ۸-۱۲ cells per ۱۰ high-power fields, a ۲۰-۲۵% increase in perimysial connective tissue thickness. Morphometric analysis demonstrated statistically significant differences (p < ۰.۰۵) in both muscle fiber diameter and fiber density compared to the control group. Birds in the control group exhibited an average fiber diameter of ۴۸.۶ ± ۳.۱ μm, whereas antibiotic-treated birds showed an average of ۴۰.۲ ± ۲.۷ μm. Fiber density also increased abnormally by ۱۵-۲۰%, indicating compensatory hypertrophy failure and impaired myofiber maturation. These findings indicate that continuous exposure to antibiotics may adversely affect skeletal muscle development by altering fiber morphology, increasing inflammatory responses, and promoting connective tissue proliferation. Understanding these pathophysiological changes is essential for optimizing antibiotic usage protocols, improving poultry production efficiency, and minimizing unintended negative impacts on meat quality and animal health.

کلیدواژه ها:

Broiler chickens ، antibiotics ، muscle tissue ، histopathology ، skeletal muscle development ، poultry physiology