Influence of high environmental temperature on egg production and shell quality: a review

Abstract

In spite of the large amounts of money invested in research, breeding, and the improvement of commercial egg-type strains, high environmental temperature (HET) has been identified as a major non-genetic constraint limiting expression of their full genetic potential. This environmental stressor has been implicated in adverse marked effects on egg production and eggshell quality of hens. Reports have conclusively indicated that poor performance (i.e. drop in egg production and poor eggshell quality) of layers reared in thermally-stressed environments could be adduced to a complex interplay of low feed intake, malfunctioning of the endocrine system, acid-base imbalance and poor physiological functioning of organs and mechanisms connected with the entire egg production process, via follicular recruitment and growth, ovulation, egg formation, shell formation, egg development, oviposition and oviposition interval.

Pemanfaatan Limbah Daun Pepaya Dalam Bentuk Tepung dan Jus Untuk Meningkatkan Performans Produksi Ayam Arab

“…Hasil penelitian Rahayu (2003) pada telur ayam merawang mempunyai skor kuning telur 7,04 ± 0,22 mm dan tebal kerabang 0,34± 0,01 mm. Oguntunji and Alabi (2010) menyatakan bahwa kerabang telur dipengaruhi oleh sifat genetik, kalsium dalam pakan, hormon, lingkungan dan manajemen.…”

HEAT STRESS IN POULTRY. I. DANGER, RELATED PHYSIOLOGICAL CHANGES AND SYMPTOMS (review)

“…Thus, the increased production of corticosterone, noradrenaline and adrenaline is observed during heat stress, which causes follicle degeneration and leads to decrease in egg-laying capacity [12,13]. Then, the activity and performance efficiency of lymphoid organs (bursa, spleen and thymus) decrease and the number of monocytes, lymphocytes and heterophils [14,15] increases, which results in lower immune response [16].…”

“…With rise of ambient temperature, in order to restore heat balance with the environment, the bird stretches the wings and slows down its motor activity; in this case, depth of breathing decreases and rate of breathing increases by a factor of about 5-6 [2, 13,38]. The blood vessels of skin, wattles and combs dilate, and internal heat is supplied to the skin surface, through which the bird organism cools down due to convection (heat radiation) [25].…”

“…In such a situation, a main way of cooling to maintain thermal homeostasis is evaporation via breathing [8,13]. When ambient temperature is above 30 С, bird breathing accelerates from 22-25 to 200-250 cycles per minute [7,40].…”

“…Stress hormones (corticosterone, noradrenaline and adrenaline) have an antagonistic effect on reproductive function via brain, hypophysis and gonads, including the reduction of normal ovary function, which leads to suppression of secretion of steroids (progesterone and estradiol) and gonadotrophins (luteinizing and folliclestimulating hormones). This results in abnormal regulation of the physiological mechanisms which are of fundamental importance for steroidogenesis, follicle development and growth, and ovulation [13,[70][71][72].…”