Environmental temperature and stocking density effects on acute phase proteins, heat shock protein 70, circulating corticosterone and performance in broiler chickens

Abstract

An experiment was conducted to determine the effect of different stocking densities on serum corticosterone (CORT), ovotransferrin (OVT), α1-acid glycoprotein (AGP) and ceruloplasmin (CP) concentrations, brain heat shock protein (HSP) 70 expression and performance in broiler chickens exposed to unheated and heated conditions. Day-old chicks were stocked at 0.100 m(2)/bird (low density (LD)) or 0.063 m(2)/bird (high density (HD)), in battery cages and housed in environmentally controlled rooms. From 21 to 35 days of age, birds from each stocking density group were exposed to either 24 or 32 °C. Growth performance was recorded during the heat treatment period, and blood and brain samples were collected to determine CORT, OVT, AGP, CP and HSP 70 levels on day 35. Heat treatment but not stocking density was detrimental to growth performance. There were significant temperature × density interactions for CORT, CP and OVT on day 35. Although HD elevated CORT, CP and OVT when compared to LD, the effects of the former were more obvious under heated condition. Both temperature and density had significant effect on AGP and HSP 70. In conclusion, irrespective of temperature, high stocking density was physiologically stressful to broiler chickens, as indicated by CORT, AGP, CP, OVT and HSP 70, but not detrimental to growth performance and survivability. As it was shown in the present study, AGP, CP and OVT could be useful biomarkers to determine the effect of overcrowding and high temperature on the welfare of broiler chickens.

Effect of dietary l‐carnitine supplementation and energy level on oxidant/antioxidant balance in laying hens subjected to high stocking density

“…Consistent with our results, Sahin et al (2014) indicated that high stocking density decreased hepatic SOD, CAT and GSH-Px activities in rainbow trout. It was demonstrated that blood total protein and albumin level significantly decreased in fish groups and broiler chickens reared at high stocking density (Najafi et al, 2015;C. It was demonstrated that blood total protein and albumin level significantly decreased in fish groups and broiler chickens reared at high stocking density (Najafi et al, 2015;C.…”

“…In addition, Simsek et al (2009) found that high stocking density decreased GPx activity, but not changed serum CAT activity. It was demonstrated that blood total protein and albumin level significantly decreased in fish groups and broiler chickens reared at high stocking density (Najafi et al, 2015; C. Tan, Sun, Tan, Guozhi, & Xiaoling, 2018). When hens are exposed to overcrowding stress, they have greater energy requirements and plasma protein mobilization increases according to the intensity of the stress to meet energy demand.…”

Central NPY ‐Y5 sub‐receptor partially functions as a mediator of NPY ‐induced hypothermia and affords thermotolerance in heat‐exposed fasted chicks

“…; Najafi et al. ). It has been further reported that the expression of HSPs could be increased by the ingestion of some nutritional supplements which help to protect cellular functions against stress (Chen et al.…”

“…; Najafi et al. ). HSP‐90 has been shown to be the most abundant constitutively expressed protein inside the cell (Stetler et al.…”

“…HSP-70 and HSP-90 are the most conserved and most widely studied of all HSPs. In birds, increased expression of HSP-70 during heat stress has been found to prevent abnormal protein synthesis and aggregation (Quinteiro-Filho et al 2010;Najafi et al 2015). HSP-90 has been shown to be the most abundant constitutively expressed protein inside the cell (Stetler et al 2010) and to have a regulatory function for the glucocorticoid receptor (GR; Hao and Gu 2014).…”