The Impact of Temperature and Humidity on the Performance and Physiology of Laying Hens

Abstract

We investigated the effect of different ambient temperatures and relative humidity (RH) with the same temperature-humidity indices (THI) on laying performance, egg quality, heterophil to lymphocyte ratio (H/L ratio), corticosterone (CORT) concentration in blood, yolk, and albumen, and plasma biochemical parameters of laying hens. Commercial hens (Hy-Line Brown; n = 120), aged 60 weeks, were allocated to two environmental chambers. Laying hens were subjected to either one of two thermal treatments—26 °C and 70% RH (TLHH75) or 30 °C and 30% RH (THHL75) for 28 days—with the same THI of 75. Neither TLHH75 nor THHL75 affected laying performance, including egg production, egg weight, egg mass, feed intake, and feed conversion ratio (p > 0.05). Plasma biochemical parameters such as total cholesterol, high-density lipoprotein cholesterol, triglycerides, calcium, magnesium, and phosphorus were not altered by the environmental treatments (p > 0.05). As for stress indicators, both environmental regimes failed to affect blood H/L ratio and CORT levels in plasma, yolk, and albumen (p > 0.05), although albumen CORT levels were elevated (p < 0.05) in TLHH75 group at day 7. Hence, our study suggests that laying hens performed and responded similarly when exposed to either TLHH75 or THHL75 characterized by the same THI. These results can serve as a scientific basis for management decisions and handling laying hens under thermally challenging conditions.

The role of corticosterone in the regulation of the cellular composition of chicken blood during the stress reaction

“…In the present study, we studied the hormone-hematological features of the stress response in the body of laying hens under conditions of an excessive increase in the density of bird laying in the cage. This initiated the appearance of heat stress signs in them, as a result of the absence of sweat glands, the presence of feathers, and the dependence of thermal regulation on the respiratory rate [15].…”

“…In particular, the immunosuppressive effects of corticosterone in birds are realized both at the level of humoral and cellular components of immunity [4], determining the effectiveness of their responses. According to [14][15][16], the severity of the primary response of birds to stressor action reflects the ratio between heterophiles and lymphocytes. This is the result of glucocorticoid-induced rapid apoptosis of lymphocytes [4].…”

“…Most aspects of the adaptive response of birds under heat stress have been studied under conditions of a sharp increase in ambient temperature, which is most significant in hot countries [1][2][3][5][6][7]. At the same time, in industrial conditions, one of the frequently violated technological parameters is the "bird laying density", a change in which also initiates the appearance of heat stress signs in the bird due to the absence of sweat glands, the insulating properties of feathers and the production of a large amount of metabolic heat [19][20][21][22][23], especially if the recommended humidity is not observed in the poultry house [15]. However, very little is known about the immune and hormonal reactions in the body of chickens under the stress effect of technological factor -laying density (crowding).…”

Cloacal temperature responses of broiler chickens administered with fisetin and probiotic (Saccharomyces cerevisiae) and exposed to heat stress

“…The major factor that negatively affects broiler chickens production in the subtropics and tropics is heat stress (Aluwong et al, 2017;Goel et al, 2021;Sugiharto et al, 2017). The combined effects of high relative humidity (RH) and high ambient temperature (AT) have been reported to induce thermal stress in chickens (Egbuniwe et al, 2015;Jiang et al, 2020;Kim et al, 2021;Qaid et al, 2021), therefore, lipid peroxidation resulting from hyperthermia may damage some of their vital organs (Rhoads et al, 2013;Al-Zghoul & Saleh, 2020;Aksoy et al, 2021;Gogoi et al, 2021). Antioxidants are used universally in dietary supplementation, and these supplements are beneficial in ameliorating tissue damages induced by stress (Gouda et al, 2020;Sun et al, 2015).…”

A Novel Method to Predict Laying Rate Based on Multiple Environment Variables

“…The above studies identified the correlation between temperature control and ammonia concentration to livestock and poultry breeding management, which can effectively improve laying rate and egg quality. Kim et al [12] showed that environmental variables of temperature and humidity had a significant influence on laying rate, which provided a scientific basis for management decisions. Guo et al [13] studied the influence of temperature on laying ducks based on the parallel vector regression prediction model.…”