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Two experiments were conducted to evaluate growth performance, immune responses and carcass traits of CARIBRO Vishal broilers fed dietary L-Thr in low protein diets without or with the balance of Lys and Met. Broilers fed 85% CP diet with Thr alone showed depressed daily weight gain (linear, p=0.004), daily feed intake (quadratic, p=0.031) and higher FCR (linear, P=0.008) at d 21 (exp. 1) whereas, birds fed low CP diets but supplemented with Thr and balance of Lys and Met exhibited similar (p>0.05) growth rate as that of control diet (exp. 2). Incremental Thr levels increased (p<0.05) the immune and digestive organs weights, and enhanced antibody responses against SRBC and PHA-P antigens in both experiments. Thr inclusion increased (p<0.001) total protein and globulin in both experiments. Dietary crude protein in broiler diets could be reduced up to 85% of fast-growing broilers' requirement with adequate supplementation of 3 limiting amino acids (Lys, Met, and Thr) for CARIBRO Vishal broiler chicks. Dietary L-Thr supplementation enhanced the immune status of broiler chickens fed low CP diets. [ABSTRACT FROM AUTHOR]

The blastoderm, which represents the fertilized germinal disc, undergoes cellular events of division, differentiation and organization to achieve embryonic development in chickens. In this study, blastodermal cell counts and hatching performance of Marshall® broiler breeders as influenced by flock age and egg storage were investigated. A total of 1,520 eggs from the flock ages, 43 weeks (younger) and 65 weeks (older), under similar management and nutritional regime were incubated after storage at 16°C with 75% relative humidity for duration of 0 (fresh eggs), 4, 7 and 10 days. Results show that total blastodermal cell counts (BCC) for both ages declined with increasing storage duration, with a sharp regression at 4d storage from younger breeders. Higher percentages of fertility and hatchability were recorded for younger breeders compared to older breeders. Percentage hatchability was statistically similar (p >.05) for both 43 weeks and 65 weeks old broiler breeders under 0, 4 and 7d storage except at 10d storage which was lower for older breeders. Chick lengths were longer with younger breeders whereas older breeders had heavier chick weights. Also, significant associations were found between BCC and fertility, hatchability of fertile eggs and chick weights, respectively, under different conditions. These results indicate that fresh eggs (0d) and short‐term stored eggs (4‐ and 7 d) from 43 weeks old breeders had higher total blastodermal cell counts, fertility, hatchability and increased chick lengths compared to 65 week old breeders which produced heavier chicks. Therefore, egg storage longer than 7 days especially from older breeders resulted in modifications to the blastoderm which subsequently affected fertility, hatchability, embryo liveability and hatched chick quality. Also, detection of BCC in fertile eggs can serve as a predictive tool in fertility and hatchability evaluations. [ABSTRACT FROM AUTHOR]