Effect of Heat Stress and Stocking Density on Growth Performance, Breast Meat Quality, and Intestinal Barrier Function in Broiler Chickens

Abstract

The present experiment was conducted to investigate the effect of heat stress (HS) andstocking density (SD) on growth performance, breast meat quality, and intestinal barrier functionin broiler chickens. Experimental treatments included two different ambient temperatures (20 °C:thermoneutral conditions, or 27.8 °C: HS conditions) and two different SD (low: 9 birds/m2 andhigh: 18 birds/m2) in a 2 × 2 factorial arrangement. A total of 1140 21-day-old broiler chickens wereallotted 1 of 4 treatments with five replicates. At the end of the experiment (35 days of age), twobirds per replicate were euthanized for sample collections. The results indicated no interactionsbetween HS and SD for all measurements. For main effects, HS decreased (p < 0.05) the growthperformance of broiler chickens. Similarly, high SD also decreased (p < 0.05) body weight gain andfeed intake. HS decreased (p < 0.01) jejunal trans-epithelial electric resistance (TER), whereas highSD did not affect TER. Neither HS nor high SD affected jejunal tight junction-related geneexpressions; however, high SD reduced (p < 0.05) occludin expression. In conclusion, HS and highSD are key environmental factors decreasing broiler performance; however, the interactive effectsof HS and high SD are not significant under the current conditions.

Dietary Betaine Improves Intestinal Barrier Function and Ameliorates the Impact of Heat Stress in Multiple Vital Organs as Measured by Evans Blue Dye in Broiler Chickens

“…Consistent with other experiments in this area [24], HS compromised the small intestinal mucosa, as evidenced by reduced villous height and crypt depth. Furthermore, as in other experiments HS reduced the TER of the small intestinal mucosa [6]. The current results indicated that HS did not influence EBD concentration in the jejunum or ileum suggesting there no discernible extravasation in the small intestine during HS.…”

“…In addition, it has been postulated that this makes them sensitive to disruptions in reductions in blood flow, which in turn can precipitate oxidative stress and hypoxic damage [28], and is a prelude to loss of intestinal barrier function, inflammatory damage and bacterial translocation [29,30]. However, there are exceptions, and under milder forms of HS the consequences are likely reduced protein synthesis and crypt cell proliferation, resulting in a gradual decline in intestinal barrier function [6], which appears to be supported by the present findings.…”

“…As the distribution of blood flow to the skin to facilitate radiant heat loss relies on a commensurate reduction in blood flow elsewhere, continued HS can precipitate dysfunction in affected organs due to reduced nutrient delivery and removal of metabolic by-products. Heat stress compromises intestinal barrier integrity in broiler chickens and other species [4][5][6], presumably by splanchnic blood restriction, and that can lead to bacterial translocation and a systemic inflammatory response [7,8].…”

Effect of Glutamine on Antioxidant Capacity and Lipid Peroxidation in the Breast Muscle of Heat-stressed Broilers via Antioxidant Genes and HSP70 Pathway

“…Broilers are heat stress sensitive animals [1]. When the ambient air temperature increases to an extent that the broilers' body cannot adjust, the body cannot expel heat in time, resulting in a heat stress reaction.…”

The Potency of Oral Administration of L-Citrulline as Anti Heat Stress Agent in KUB Chickens.

“…Heat stress reduces laying percentage, egg size, eggshell durability, and body weight gain, as well as increases mortality in layers (Sterling et al, 2003;Lin et al, 2004;Franco-Jimenez and Beck, 2007). Also, it appears to have a detrimental impact on poultry meat quality, however, it has been reported that breast meat characteristics remain unaffected by heat stress (Goo et al, 2019).…”