Productive, physiological and immunological performance under heat stress and different light programs in laying hens

Abstract: Two developed strains of laying hens "Silver Montazah and Matrouh" strains from 22-42 weeks of age were used in the present study. They were housed in floor pens divided into eight treatments including 2 environmental temperature, 2 lighting programs, 2 selenium yeast levels or their combinations. Heat stressed birds exposed to 39 ± 1 °C for 4 hours/day for 4 consecutive days, while the control exposed to the normal ambient temperature (from 23 to 24°C). Selenium Yeast was added to rations with a concentration of 0.4 mg/kg diet.
Results showed that: body weight, body weight gain and growth rate of Silver Montazah strain was significantly higher than Matrouh strain. Heat stress and 18 hr. light decreased these traits compared with control. Organic selenium significantly improved the productive performance of both strains. Feed intake (F1) was higher in Silver Montazah than Matrouh strain. Heat stress and 18 hr. lighting regime decreased F1 compared with control, while selenium yeast increased feed consumption compared with control. Heat stress significantly increased the expression of heat shock protein 70 (HSP70) but the expression of HSP 90, HSP60 and HSP40 was not significant compared with control. A significant increase in the expression of HSP70, HSP60 and HSP40 and non significant increase in HSP90 for 18 hr. compared with 16 hr. light groups. Silver Montazah strain was higher significantly in the expression of HSP70 and HSP90 compared with Matrouh strain. The addition of anti stress reduced the expression of all types of HSPs.
Heat stress and 18 hr. light reduced the immune responses (antibody production) against sheep red blood cells (SRBCs), Newcastle virus and Influenza virus compared with control, while using selenium yeast increased these immune responses. Body temperature (BT) and respiration rate (RR) in heat stressed hens were significantly higher than those of control, and in Silver Montazah than Matrouh strain, but this increase was not significant. Also, BT and RR were higher in the treatments that subjected to 18 hr. light compared with 16 hr. Addition of anti stress exerted positive effect by reducing both BT and RR under heat stress condition. Mortality rate (MR) was significantly higher in heat stressed and 18 hr light-exposed hens compared with controls also in Silver Montazah than Matrouh strain. Organic Se reduced MR, but this reduction was not significant. Heat stress had the same negative effect as the treatment of 18 hr. light on blood measurements, where they caused a reduction in both plasma total protein and globulin concentration, elevation of albumin concentration, but the differences were not significant. Calcium and phosphorus were reduced, but total cholesterol and T3 hormone were increased. Egg production rate was higher in short light regime, and in Silver Montazah strain than Matrouh strain. Heat stress reduced egg production rate but the addition of organic selenium had a positive effect on this respect. Heat stress and 18 hr. lighting treatment decreased all egg quality traits compared with control.
It is recommended to supply 0.4 mg/kg diet organic selenium for laying hens diet to improve their performance.
Key Words: heat stress, light program, selenium yeast, laying hens, performance, blood parameters.
Publication year 2012
Pages PP. 102
Availability location مكتبة معهد بحوث الانتاج الحيوانى-شارع نادى الصيد- الدقى- الجيزة
Availability number 1192
Organization Name
Country Egypt
Author(s) from ARC
Agris Categories Animal physiology - Nutrition
Blood composition. Heat stress. Layer chickens. Performance testing.
Proposed Agrovoc selenium yeast;light program;
Publication Type PhD Thesis