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