Supplemental boric acid does not prevent the development of footpad dermatitis in broilers subjected to high stocking density

The present study was conducted to evaluate the protective effect of dietary boric acid supplementation on the development of incidence and severity of footpad dermatitis (FPD) in broiler chickens subjected to normal or high stocking densities (NSD or HSD). A total of 576 1-day-old ROSS 308 broiler chickens were randomly allocated to 4 treatments (8 replicate pens per treatment) in a 2 x 2 factorial arrangement of dietary boric acid (0 and 60 mg/kg) and stocking density (NSD 14 birds/m(2) and HSD 22 birds/m(2)). Basal diets were formulated for starter, grower, and finisher phases. Growth performance, litter quality (litter pH, moisture, temperature, and NH3 volatilization), serum and litter boron levels, and incidence and severity of FPD were recorded. The HSD affected the body weight gain and feed intake of broiler chickens during all phases and 0 to 42 (P < 0.05), whereas feed conversion ratio (FCR) was poor at 0 to 21 days only. Dietary boric acid had no effect on the growth performance of broiler chickens. Litter pH, moisture, and NH3 volatilization were higher in broiler chickens subjected to HSD (P < 0.05). Thus, the incidence and severity of FPD increased in response to HSD (P < 0.05). Dietary boric acid reduced the litter pH and NH3 volatilization on day 42 of experiment (P < 0.05). However, dietary boric acid supplementation had no effect on the incidence and severity of FPD. Boric acid supplementation in broiler diets increased the serum and litter boron levels at day 42 in broiler chickens subjected to NSD or HSD (P < 0.05). In conclusion, HSD resulted in poor growth performance, litter quality, and greater incidence and severity of FPD in broiler chickens. Dietary boric acid was ineffective against FPD in broiler chickens although it improved the litter quality by lowering the litter pH and NH3 volatilization.