Student Competition: Nutrition Iii

This experiment was conducted to examine the effect of dietary supplement with green Brazilian propolis on body weight (BW), weight gain (BWG) and cecal microflora in broiler chickens raised under heat stress condition. A total of 504 15-d-old male broiler chickens (Ross 708) were randomly allocated to 6 treatments, each with 4 replicate pens per treatment, 21 chickens per pen from hatch to 42 d of age. The dietary treatments were basal diet (control) and 5 different concentrations of propolis (100, 250, 500, 1,000, and 3,000 mg /kg diet). The average temperature and relative humidity during the day time was (31.7 ± 0.3°C and 56 ± 4) while at night were (28.8 ± 0.4°C and 58 ± 3), respectively. Performance data were normally distributed; while microbial data were logarithm transformed (log10). Data were analyzed using a complete randomized design and ANOVA was performed using PROC MIXED (SAS Inst. Inc., Cary, NC). Supplementation of diets with propolis did not significantly (P > 0.05) affect BW, BWG and cecal enumeration of Escherichia coli, coliforms, Enterococcus spp., and Lactobacillus. However, the Bifidobacteria spp. population was significantly (P = 0.005) lower in birds fed the diet with 1,000 mg of propolis/kg than controls and those supplemented with 100 mg of propolis/kg of diet. In conclusion, the results indicate that dietary supplement with green Brazilian propolis, from 100 to 3,000 mg/kg, does not induce favorable influences on BW, BWG, and cecal microflora of broilers reared under heat stress conditions.