Circulating metabolic and reproductive hormone changes in laying hens kept under various heat-combating systems

Abstract

The objective of the present study was to observe the circulating metabolic, reproductive, and stress hormones in laying hen performance under different heat-combating systems (HCSs). A total of 500 White Leghorn pullets at 24 weeks of age were subjected to four HCSs, i.e. desert cooling (DC), water sprinkling (WS), time limit feeding (TLF), and ascorbic acid (AA) supplementation, at environmental temperatures from 32.30 to 40.80 °C with 76.40% relative humidity. Blood was collected before heat stress, at peak stress, and after heat stress to collect plasma. The results of the 24-week stress period showed significantly less circulating T 3 , T 4 , estrogen, and progesterone in the control group in the peak stress period, whereas corticosterone was significantly higher. The plasma T 3 , T 4 , and estrogen and the egg production percentage remained significantly higher in the DC system as compared to other HCSs and the control. In comparison, the plasma progesterone level was significantly increased with lower T 4 in the AA supplementation group than the other HCSs. Our results validate the potential role of the DC system in protecting birds from environmental heat stress effects and subsequent improvement in egg production.

Effect of prenatal ambient temperature on the performance physiological parameters, and oxidative metabolism of Japanese quail (Coturnix coturnix japonica) layers exposed to heat stress during growth

“…Low ovarian activity and egg production may also stem from alterations in neurotransmitter activity 24 , reduced blood flow to the ovary, and lower secretion of the hormones triiodothyronine, estrogen, progesterone, follicle-stimulating hormone, and luteinizing hormone 25 . Rozenboim et al 26 suggested that heat stress directly influences ovarian activity by reducing plasma levels of steroid hormones and expression of steroidogenic enzymes in follicles, which may prevent follicle development 27 – 29 .…”

Differential effects of experimental hyperthyroidism on declined immunity of broiler chicken

“…The serum was kept stored at −20°C for further analysis. For the detection of hormones, the methods were adopted as described elsewhere by Biswas, Mohan, and Sastry () and Anjum, Sandhu, Rahman, and Safdar (). Serum total T 3 and T 4 were quantified by the use of ELISA kits according to the manufacturer's instructions.…”

“…The serum was kept stored at −20°C for further analysis. For the detection of hormones, the methods were adopted as described elsewhere by Biswas, Mohan, and Sastry (2010) and Anjum, Sandhu, Rahman, and Safdar (2016…”