title: 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.
authors.affiliation: *Mineral Nutrition Research Division, Institute of Animal Sciences, Chinese Academy of Agricultural Sciences, Beijing, People's Republic of China.
authors.forename: Jingjing
authors.initials: J
authors.lastname: Xie
authors.affiliation: *Mineral Nutrition Research Division, Institute of Animal Sciences, Chinese Academy of Agricultural Sciences, Beijing, People's Republic of China Animal Nutrition Institute, Sichuan Academy of Animal Science, Chengdu, People's Republic of China.
authors.forename: Li
authors.initials: L
authors.lastname: Tang
authors.affiliation: *Mineral Nutrition Research Division, Institute of Animal Sciences, Chinese Academy of Agricultural Sciences, Beijing, People's Republic of China.
authors.forename: Lin
authors.initials: L
authors.lastname: Lu
authors.affiliation: *Mineral Nutrition Research Division, Institute of Animal Sciences, Chinese Academy of Agricultural Sciences, Beijing, People's Republic of China.
authors.forename: Liyang
authors.initials: L
authors.lastname: Zhang
authors.affiliation: Department of Animal Science, North Carolina State University, Raleigh, NC, USA.
authors.forename: Xi
authors.initials: X
authors.lastname: Lin
authors.affiliation: Department of Animal Science, North Carolina State University, Raleigh, NC, USA.
authors.forename: Hsiao-Ching
authors.initials: HC
authors.lastname: Liu
authors.affiliation: Department of Animal Science, North Carolina State University, Raleigh, NC, USA.
authors.forename: Jack
authors.initials: J
authors.lastname: Odle
authors.affiliation: Department of Animal Science, North Carolina State University, Raleigh, NC, USA wlysz@263.net.
authors.forename: Xugang
authors.initials: X
authors.lastname: Luo
mesh_terms: D000818:Animals; D001774:Blood Chemical Analysis / Q000662:veterinary; D002645:Chickens / Q000502:physiology*; D004797:Enzyme-Linked Immunosorbent Assay / Q000662:veterinary; D005260:Female; D018869:Heat-Shock Response; D006728:Hormones / Q000097:blood*; D016877:Oxidants / Q000378:metabolism*; D011863:Radioimmunoassay / Q000662:veterinary; D011897:Random Allocation
chemical_list: D006728:Hormones; D016877:Oxidants
keywords: broiler breeder; heat stress; hormone; metabolite; oxidation