Effects of acute and chronic heat stress on plasma metabolites, hormones and oxidant status in restrictedly fed broiler breeders

Abstract

Heat tolerance can be improved by feed restriction in broiler chickens. It is unknown whether the same is true for broiler breeders, which are restrictedly fed. Therefore, the current study was conducted to study the effects of heat stress on plasma metabolites, hormones, and oxidative status of restricted fed broiler breeders with special emphases on the temperature and latency of heat exposure. In trial 1, 12 broiler breeders were kept either in a thermoneutral chamber (21°C, control, n = 6) or in a chamber with a step-wise increased environmental temperature from 21 to 33°C (21, 25, 29, 33°C, heat-stressed, n = 6). Changes in plasma total cholesterol, glucose, and triiodothyronine (T3) were closely related to the environmental temperature. When the temperature reached 29°C, plasma T3 (P < 0.05) was significantly decreased in acute heat-stressed birds, whereas plasma glucose (P < 0.001) and cholesterol (P = 0.002) increased only when the temperature reached 33°C. Plasma triglyceride (P = 0.026) and creatine kinase (CK, P = 0.018) were lower in heat-stressed birds than controls regardless of the temperatures applied. In Trial 2, 24 broiler breeders were divided into 2 groups and raised under 21°C and 32°C for 8 weeks, respectively. Total cholesterol was increased in chronic heat-stressed broiler breeders after 4 weeks. Plasma lactate dehydrogenase (LDH, P = 0.047) and glutamic-oxaloacetic transaminase (GOT, P = 0.036) was up-regulated after 6 weeks of thermal treatment, whereas plasma CK (P = 0.009) was increased at the end of thermal treatment. Plasma malonaldehyde, protein carbonyl content, activity of total superoxide dismutase (SOD), and corticosterone content were not altered after acute and prolonged heat challenges. Taken together, acute heat stress primarily resulted in disturbance of plasma metabolites, whereas chronic heat stress caused tissue damage reflected by increased plasma LDA, GOT, and CK. During acute heat stress, plasma metabolites were minimally disturbed in broiler breeders until the environmental temperature reached 33°C.

The effects of Environmental Enrichment on Some Physiological and Behavioral Parameters of Broiler Chicks

“…Eleroglu et al (2015) determined rectal temperatures of female and male chicks measured in the sixth week were as 41. (Xie et al, 2015). The current findings are in agreement with the mentioned studies.…”

Effect of dietary supplementation with &lt;i&gt;Rhizopus oryzae&lt;/i&gt; or &lt;i&gt;Chrysonilia crassa&lt;/i&gt; on growth performance, blood profile, intestinal microbial population, and carcass traits in broilers exposed to heat stress

“…In this study, HS seemed to contribute to the inflammatory condition in broilers as indicated by the higher H/L ratio in HS than in CONT birds (though statistically not significant). It is known that HS was associated with the increased corticosterone level (Sohail et al, 2012) leading to tissue damage in birds (Xie et al, 2015). Interestingly, there was no significant difference in serum total protein between CONT and HS birds provided with fungi.…”

Antioxidant Systems in Poultry Biology: Superoxide Dismutase

“…On the other hand, heat stress increased SOD and decreased GSH-Px activities of mitochondria regardless of muscle types [120]. Interestingly, in restrictedly fed broiler breeder's plasma MDA, protein carbonyl content, activity of SOD and corticosterone content were not altered after acute (33°C) and prolonged heat challenges [121]. Probably the stress intensity was not high enough to upregulate SOD.…”