Preliminary Tolerability Assessment of Continuous Dietary Meloxicam in Broilers

The anti-inflammatory activity of antimicrobial growth promoters (AGPs) has been proposed as one mechanism contributing to their beneficial effects on broiler performance, raising interest in pharmacological modulation of inflammation as a non-antibiotic strategy. This proof-of-concept dose-escalation study evaluated the safety of prolonged dietary exposure to meloxicam (MLX) and explored its effects on performance. Seventy one-day-old male Cobb 500 broilers were allocated to five treatments (n = 14): basal diet (BD), BD supplemented with 55 ppm zinc bacitracin (ZB), or MLX at 0.4, 1.2, or 3.6 mg/kg body weight. Birds were monitored for 42 days, with growth performance, hematology, serum biochemistry, and histopathology evaluated. No consistent treatment-related hematological alterations occurred, and serum biochemistry was unaffected at day 21. At day 42, MLX produced dose-related changes in albumin, calculated globulin, and alanine aminotransferase, while alkaline phosphatase showed a quadratic response. Feed intake differed at selected time points, but MLX did not consistently alter growth performance. Performance also did not differ from the ZB. No apparent treatment-related patterns of histopathological lesions were identified in the birds examined. No overt toxicity was detected under the conditions and sample sizes evaluated, although selected biochemical responses at day 42 warrant further investigation. These preliminary findings support studies with defined inflammatory challenges and specific pharmacodynamic markers but do not establish the safety or growth-promoting efficacy of prolonged dietary MLX administration.