Abstract
A 42-day experiment was conducted to investigate the interactive effects of a stimbiotic (STB) and wheat bran (WB) in broiler chickens receiving diets (DT) based on corn or wheat. A total of 960 Cobb 500 male broiler chicks at zero-day old were allocated to 64 pens with 8 treatments, 8 replicates per treatment, and 15 birds per replicate. The treatments were arranged in a randomized complete block design with 2 × 2 × 2 factorial, with the factors as diet (corn-soybean meal or wheat-soybean meal), STB (with or without), and WB (0 or 50 g/kg). Body weight gain (BWG), feed intake (FI), and mortality-corrected FCR data were collected for the starter (d 0-10), grower (d 10-28), and finisher (d 28-42) phases. Ileal digesta and jejunal tissue were collected on d 18 and 42. Data were analyzed as a 2 × 2 × 2 factorial using a mixed model of JMP. There was no significant 3-way interaction for growth performance and expression of nutrient transporters. There was a significant SB × WB for FCR (P < 0.05) in the grower phase. Stimbiotic supplementation and WB inclusion individually improved (P < 0.05) FCR regardless of cereal type, but this effect was not observed when the two were combined. In the overall phase (d 0-42), birds receiving corn-based diets had higher (P < 0.05) FI and BWG than those receiving wheat-based diets. There was a significant 3-way interaction for ileal digestible energy (IDE) (P < 0.05) and N digestibility (ND) on d 18 and 42 (P < 0.05). There was no effect of STB or WB in corn-based diets, whereas WB inclusion decreased IDE in wheat-based diets, but STB supplementation increased IDE with or without WB. In corn-based diets, WB inclusion increased ND, whereas ND was decreased in wheat-based diets. Supplementation with STB had no effect on ND, but STB increased ND in wheat-based diets with and without WB. Ileal DE was greater (P < 0.05) for wheat- than corn-based diets on d 42. Wheat bran inclusion increased ND in corn-based diets whereas, with STB supplementation, there was no difference in ND with or without WB. There was no difference in ND with or without STB or WB in wheat-based diets. There was a significant STB × DT on the expression of GLUT-1 (P < 0.05). In corn-based diets, STB produced an upward expression of GLUT-1, whereas in wheat-based diets, STB supplementation had no effect. On d 42, stimbiotic supplementation produced upward (P < 0.05) expression of SGLT-1. In conclusion, STB supplementation in wheat- or corn-based diets and with WB inclusion improved energy digestibility. On the other hand, WB inclusion in wheat-based diets decreased nutrient digestibility especially on d 18, thus making room for a positive response to STB supplementation in wheat-based diets compared to the marginal response to STB supplementation observed in corn-based diets.