An attempt to alleviate heat stress and improve laying hen performance and egg quality during summer season by using some amino acids or vitamins [electronic resouce].

Includes references.

A total number of 540 Bovans Brown laying hens at 50 weeks of age were used in this study to determine the possibility of alleviating heat stress by using some amino acids (methionine or lysine) or vitamins (C or E) as well as the effect on laying hen performance, egg quality, nutrients digestibility and economic efficiency of egg production during summer season (the ambient temperature ranged between 29.5 – 35.6 Co and relative humidity from 50 to 60 %). Three levels of either methionine, lysine, Vit C, or Vit. E were used in this study. Methionine levels were 100% (control), 120 % (M1) or 140 % (M2) and lysine levels were 100% (control), 110 % (L1) or 120 % (L2) of requirement according to the strain recommended catalogue. While, the supplemental levels of Vit. C were 0 mg/kg (control), 1000 mg/kg (C1) and 2000 mg/kg of the diet (C2) and Vit. E levels were 0 mg/kg (control), 250 (E1) and 500 mg/kg of the diet (E2). The 1st diet which contained 100 % of both methionine and lysine requirements without supplemental vitamins represents the control diet. Laying hens were kept in cages of wire floored batteries in an open system house under similar conditions of managements. Water and feed were offered ad-libitum under a total of 16 hours light/day regimen. The results indicated that feeding laying hens on diets supplemented with different levels of either methionine, lysine, Vit. C or E recorded higher values of egg production, egg weight and improved feed conversion ratio compared to control group. While, there were no significant (P<0.05) differences in feed intake values due to the different dietary treatments. Also, results showed an improvement in egg shell thickness, digestibility coefficient of organic matter (OM), crude protein (CP), ether extract (EE) and economic efficiency due to experimental treatments compared to control group. In conclusion, using either methionine, lysine, Vit. C or E at the tested levels of this study improved laying hen performance, egg quality, nutrients digestibility and economic efficiency of egg production during summer season.

Summary in Arabic.

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