Cello-oligosaccharide ameliorates heat stress-induced impairment of intestinal microflora, morphology and barrier integrity in broilers

The study evaluated whether feeding cello-oligosaccharide (COS) could ameliorate heat stress-induced impairment of intestinal microflora, morphology and barrier integrity in broilers. Three hundred and sixty 21-d-old Ross 308 male broilers were used in a 2 × 2 factorial design, and the main factors consisted of diet (basal diet or addition of 1.5 g/kg COS) and temperature (thermoneutral zone or heat stress). Each of the four treatments was replicated six times with fifteen broilers per replicate. Heat stress broilers were subjected to cyclic heat stress by exposing them to 33 °C from 0800 to 1800 and 22 °C from 1800 to 0800 to the end of the experiment (d 42). The results showed that heat stress reduced (P<0.05) average daily gain, average daily feed intake, jejunal villus height and villus height to crypt depth ratio, viable counts of Lactobacillus in cecal contents, and transepithelial electrical resistance in jejunum, while increased (P<0.05) viable counts of Escherichia coli in cecal contents and jejunal paracellular permeability of fluorescein isothiocyanate dextran 4 kDa (FD4). As compared with heat stress group feeding basal diet, supplemental COS increased (P<0.05) jejunal villus height and villus height to crypt depth ratio, as well as decreased (P<0.05) jejunal paracellular permeability of FD4. The results demonstrated that COS supplementation partially ameliorated the adverse effects caused by heat stress in broilers through improving intestinal microflora, morphology and barrier integrity.