AUTHOR=Tabler Travis W. , Greene Elizabeth S. , Orlowski Sara K. , Hiltz Joseph Z. , Anthony Nicholas B. , Dridi Sami 

TITLE=Intestinal Barrier Integrity in Heat-Stressed Modern Broilers and Their Ancestor Wild Jungle Fowl

JOURNAL=Frontiers in Veterinary Science

VOLUME=7

YEAR=2020

URL=https://www.frontiersin.org/journals/veterinary-science/articles/10.3389/fvets.2020.00249

DOI=10.3389/fvets.2020.00249

ISSN=2297-1769

ABSTRACT=<p>High environmental temperature has strong adverse effects on poultry production, welfare, and sustainability and, thereby, constitutes one of the most challenging stressors. Although colossal information has been published on the effects of heat stress on poultry productivity and gut health, the fundamemntal mechanisms associated with heat stress responses and intestinal barrier function are still not well defined. The aim of the present study was, therefore, to determine the effects of acute (2 h) heat stress on growth performance, gut integrity, and intestinal expression of heat shock and tight junction proteins in slow- (broilers of the 1950's, ACRB), moderate- (broilers of 1990's, 95RAN), rapid-(modern broilers, MRB) growing birds, and their ancestor wild jungle fowl (JF). Heat stress exposure significantly increased the core body temperature of 95RAN and MRB chickens by ~0.5–1°C, but not that of JF and ACRB compared to their counterparts maintained at thermoneutral conditions. Heat stress also depressed feed intake and increased serum fluorescein isothiocyanate-dextran (FITC-D) levels (<italic>P</italic> &lt; 0.05) in modern broilers (95RAN and MRB) but not in JF and ACRB, indicating potential leaky gut syndrome. Molecular analyses showed that heat stress exposure significantly up regulated the duodenal expression of occludin (<italic>OCLN)</italic> and lipocalin (<italic>LCN2)</italic> in ACRB, zonula occludens (<italic>ZO-2)</italic>, villin1 <italic>(VIL1)</italic>, and calprotectin (<italic>CALPR)</italic> in 95 RAN, and only <italic>CALPR</italic> in MRB compared to their TN counterparts. In the jejunum however, heat stress down regulated the expression of PALS1-associated tight junction protein (<italic>PATJ)</italic> in ACRB, 95RAN, and MRB, and that of cadherin1 (<italic>CDH1)</italic> in MRB. In the ileum, heat stress significantly down regulated the expression of <italic>OCLN</italic> in 95 RAN, <italic>ZO-1</italic> in MRB, gap junction protein alpha1 (<italic>GJA1)</italic> in JF, and <italic>VIL1</italic> in ACRB compared to their TN counterparts. In summary, this is the first report, to our knowledge, showing that tight junction protein expression is environmental-, genotype-, and intestinal segment-dependent and identifying molecular signatures, such as <italic>CDH1, CALPR</italic>, and <italic>ZO-1</italic>, potentially involved in leaky gut syndrome-induced by heat stress in MRB.</p>