Effects of different probiotic application methods and diet types on performance, carcass characteristics, serum lipids, jejunal histomorphology, cecal microflora population and immune responses in broiler chickens.

This study was conducted to assess the effects of different short-term water-soluble probiotic application methods (PAM), by a probiotic containing Enterococcus faecium, to reduce probiotic application cost with 2 types of diet (TOD) on performance, carcass characteristics, serum lipids, jejunal histomorphology, cecal microflora population and immune responses in broiler chickens. Five hundred sixty day-old male Ross 308 chicks were randomly distributed in a completely randomized design with 4 × 2 factorial arrangement consisting of probiotic spray in hatchery (PSH), the first 3 d probiotic application via drinking water (TW), PSH plus the first 3 d probiotic application via drinking water (PSH+TW) and a negative control, each with 2 TOD (corn or wheat-based diet). Each of the 8 treatments was fed to 5 replicates (14 birds/pen) from 0 to 42 d of age based on 3 phases of feeding (starter 0–10 d, grower 11–24 d, and finisher 25–42 d). The results indicate that the performance of starter and grower period were significantly improved (P < 0.05) by corn and wheat based diet, respectively. Although PSH improved broiler BW gain (BWG) in the grower period (P < 0.05), it did not improve final BWG. The PSH+TW treatment had negatively significant effect (P < 0.05) on final BWG. Corn based diet had a significantly positive effect (P < 0.05) on carcass characteristics, whereas PAM did not. PAM and wheat-based diet had a significant effect (P < 0.05) on reduction of serum cholesterol and HDL at 42 d of age, respectively. Corn-based diet and PAM significantly (P < 0.05) reduced jejunal epithelium thickness and goblet cell number at 44 d of age. Wheat-based diet had significantly (P < 0.05) higher number of cecal E. coli population at 44 d of age. Neither TOD nor PAM had any significant effects (P > 0.05) on immune responses at different periods of age. These results suggest that TOD had no significant effect on final BW but influenced carcass characteristics. In conclusion, short-term probiotic application method is not recommended for this probiotic.

Key Words: broiler, diet type, probiotic