title: Effect of a probiotic mixture on intestinal microflora, morphology, and barrier integrity of broilers subjected to heat stress.
abstract: The current study investigated the efficacy of a probiotic mixture on ameliorating heat stress-induced impairment of intestinal microflora, morphology, and barrier integrity in broilers. The probiotic mixture contained Bacillus licheniformis, Bacillus subtilis, and Lactobacillus plantarum. Three hundred sixty 21-d-old Ross 308 male broilers were allocated in 4 experimental treatments, each of which was replicated 6 times with 15 broilers per replicate. A 2 × 2 factorial design was used in the study, and the main factors were composed of diet (basal diet or addition of 1.5 g/kg of probiotic mixture) and temperature (thermoneutral zone or heat stress). From d 22 to 42, birds were either raised in a thermoneutral zone (22°C) or subjected to cyclic heat stress by exposing them to 33°C for 10 h (from 0800 to 1800) and 22°C from 1800 to 0800. Compared with birds kept in the thermoneutral zone, birds subjected to heat stress had reduced ADG and ADFI; lower viable counts of Lactobacillus and Bifidobacterium and increased viable counts of coliforms and Clostridium in small intestinal contents; shorter jejunal villus height, deeper crypt depth, and lower ratio of villus height to crypt depth; decreased jejunal transepithelial electrical resistance and a higher level of jejunal paracellular permeability of fluorescein isothiocyanate dextran 4 kDa; and downregulated protein levels of occludin and zonula occludens-1 (P < 0.05). Supplemental probiotics increased (P < 0.05) small intestinal Lactobacillus and Bifidobacterium, jejunal villus height, protein level of occludin, and decreased (P < 0.05) feed to gain ratio and small intestinal coliforms. These results indicate that dietary addition of probiotic mixture was effective in partially ameliorating intestinal barrier function. But no temperature × diet interaction was observed in the present study, revealing that the supplemented probiotics had the same effect at both temperatures.
authors.affiliation: Institute of Feed Science, Zhejiang University, Hangzhou 310058, China.
authors.forename: J
authors.initials: J
authors.lastname: Song
authors.forename: K
authors.initials: K
authors.lastname: Xiao
authors.forename: Y L
authors.initials: YL
authors.lastname: Ke
authors.forename: L F
authors.initials: LF
authors.lastname: Jiao
authors.forename: C H
authors.initials: CH
authors.lastname: Hu
authors.forename: Q Y
authors.initials: QY
authors.lastname: Diao
authors.forename: B
authors.initials: B
authors.lastname: Shi
authors.forename: X T
authors.initials: XT
authors.lastname: Zou
mesh_terms: D000821:Animal Feed / Q000032:analysis; D000818:Animals; D030161:Avian Proteins / Q000235:genetics / Q000378:metabolism; D001407:Bacillus / Q000737:chemistry; D015153:Blotting, Western / Q000662:veterinary; D002645:Chickens / Q000033:anatomy & histology / Q000254:growth & development / Q000382:microbiology* / Q000502:physiology*; D004032:Diet / Q000662:veterinary; D005786:Gene Expression Regulation / Q000187:drug effects*; D018869:Heat-Shock Response / Q000187:drug effects*; D007422:Intestines / Q000033:anatomy & histology / Q000187:drug effects* / Q000382:microbiology / Q000502:physiology; D048191:Lactiplantibacillus plantarum / Q000737:chemistry; D008297:Male; D064307:Microbiota / Q000187:drug effects; D019936:Probiotics / Q000008:administration & dosage / Q000378:metabolism*; D013696:Temperature; D062725:Tight Junction Proteins / Q000235:genetics / Q000378:metabolism
chemical_list: D030161:Avian Proteins; D062725:Tight Junction Proteins
keywords: broiler; heat stress; intestinal barrier; intestinal microflora; probiotic