response of two broiler strains to dietary supplementation of fermented wheat bran with aspergillus niger and aspergillus oryzae under heat stress conditions

Previous studies have documented the synthesis of prebiotics from agricultural wastes using aspergillus fungi in solid-state fermentation. this study investigated the effects of dietary supplementation with fermented wheat bran (fwb), produced through solid-state fermentation with aspergillus niger and aspergillus oryzae, on broiler performance and intestinal morphology under cyclic heat stress conditions. the experiment followed a 4 × 2 factorial design, incorporating four fwb inclusion levels (0.00, 0.05, 0.10, and 0.15% of the diet, representing control and low, moderate, and high supplementation levels, respectively) and two broiler strains (arian and ross 308), with six replicates of six female chicks each. a total of 576 one-day-old chicks (288 ross 308 and 288 arian) was randomly assigned to treatment groups housed in wire mesh cages. from days 22 to 35, all birds were exposed to heat stress (hs). dietary supplementation with 0.15% fwb significantly decreased feed intake (p<0.05) in both broiler strains during the period following hs exposure (35-42 d). among arian broilers, a high level of fwb supplementation resulted in poorer performance under hs conditions (22-35 days of age). in contrast, ross broilers fed with 0.05% fwb demonstrated improved feed conversion ratio (fcr) throughout the rearing period (p<0.05). additionally, all fwb supplementation levels were linked to a reduction in jejunal and ileal villus surface area in arian chickens (p<0.05). these findings highlight the importance of exercising caution when recommending fermented wheat bran as a feed additive for broilers. key factors such as the broiler strain, appropriate dosage, and the potential presence of mycotoxins—particularly ochratoxin a—must be carefully considered to ensure safety and effectiveness.