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The present study was conducted to investigate effects of L-carnitine supplied with drinking water on performance and egg quality of laying hens under high environmental temperature. In the study, 47-week-old laying hens (Brown hisex) were divided into two groups (control and treatment) and fed with a standard layer diet. Treatment group was received 50 p.p.m L-carnitine with drinking water for an 8-week period. Throughout the study, 8 h hot (35-37 degrees C) and 16 h thermoneutral (20-22 degrees C) environmental temperature regime was employed daily. The results showed that L-carnitine supplementation affected some egg quality characteristics of layers under high environmental temperature. Relative albumen weight and height were increased (p < 0.05) by supplemental L-carnitine. Live weight gain, feed intake, egg mass, egg weight, yolk weight, shell weight, yolk index, egg-shape index, yolk colour score and shell thickness were not affected (p < 0.05) by L-carnitine. It is concluded that L-carnitine supplementation in laying hens could have potential to improve albumen quality under high environmental temperature.

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The present study was initiated to determine whether dietary supplemental L-carnitine and ascorbic acid affect growth performance, carcass yield and composition, abdominal fat and plasma L-carnitine concentration of broiler chicks reared under normal and high temperature. During the experiment, two temperature regimes were employed in two experimental rooms, which were identical but different in environmental temperature. The regimes were thermoneutral (20-22 degrees C for 24 h) or recycling hot (34-36 degrees C for 8 h and 20-22 degrees C for 16 h). One-day-old broiler chicks (ROSS) were used in the experiment. A 2 x 2 x 2 factorial arrangement was employed with two levels (0 and 50 mg/kg) of supplemental L-carnitine and two levels (0 or 500 mg/kg) of supplemental ascorbic acid in drinking water under thermoneutral or high temperature regimes. Body weight gain was affected by high temperature. However, body weight gain was significantly improved in animals receiving supplemental L-carnitine, ascorbic acid or L-carnitine + ascorbic acid compared to animals receiving unsupplemented diet under high temperature. On the other hand, supplemental L-carnitine or L-carnitine + ascorbic acid reduced body weight gain under thermoneutral condition. Supplemental ascorbic acid significantly improved feed conversion efficiency, the improvement was relatively greater under high temperature. The L-carnitine content in the plasma was higher in the groups receiving supplemental L-carnitine and ascorbic acid under high temperature, while broilers fed supplemental L-carnitine and ascorbic acid had a decreased level of plasma L-carnitine concentration under normal temperature. It is concluded that dietary supplemental L-carnitine or L-carnitine + ascorbic acid may have positive effects on body weight gain, carcass weight under high temperature conditions.

-This study was performed to determine the effect of shell colour in eggs acquired from Ross-308 broiler breeders on the interior and exterior quality of the egg, the antibody content of the egg yolk, and growth performance. The shell colours of a total of 1350 eggs were classified, using a colorimeter, into three groups: dark (E<64), medium (E:64.00-67.00), and light (E>67). The difference between groups with respect to egg weight, shape index, shell weight, and Haugh unit value was significant. Egg yolk antibody content (IgY) was 6.658 mg/mL in the dark colour group, 5.130 mg/mL in the medium colour group, and 5.242 mg/mL in the light colour group. Among incubation characteristics, the fertility rate as, in order, 94.66%, 92.14%, and 87.92% in dark, medium, and light shell colour eggs, and the hatchability was 87.00%, 84.28%, and 80.57%, in the same order. No significant difference was observed between groups with respect to hatchability of fertile eggs and embryonic mortality rates. No significant difference was observed between groups for live weight, feed intake, and feed conversion ratio either. The eggshell colour has an effect on yolk antibody content and on the hatchability, but it has no influence on hatchability of fertile eggs, Haugh unit and growth performance.