ABSTRACT. The experiment was conducted with 644 Ross fertilized egg by 7 treatments 4 replicates and 23 eggs in each. Seven treatments included two control with and without injection, iron sulfate, iron sulfate nanoparticles, Alimet, Alimet + iron sulfate, Alimet + iron sulfate nanoparticles. After hatching 2 mg iron nanoparticles were applied as new treatment. The highest increased in the intestinal relative weight (p < 0.05) was observed by iron+Alimet in late feeding at day old of age. Also similar trend was found in cecum and duodenum length by iron control 2 and late feeding (18 hours’ after hatching). The highest cecum length was found among all treatments by in ovo injection of iron nanoparticles in early feeding at 21 days of age (p < 0.05). Significantly increased the duodenum length was found by iron sulfate in early feeding at 42 days of age (p < 0.05). In ovo injection of Alimet in late feeding was resulted in decrease jejunum crypt depth at 21 days of age (p < 0.05). The results of this study have shown that the highest jejunum villi width and surface area were recorded in dietary iron sulfate nanoparticles in late feeding at 21 and 42 days of age (p < 0.05).

RESUMO O efeito de proteína bruta (PB), amino ácido (AA) e balanço alimentar eletrolítico (DAE) foi avaliado por parâmetros sanguíneos, características da carcaça e desempenho de aves de corte sob estresse calórico (29-34°C). Quinhentos e quarenta machos (Ross 308) foram alocados em 12 regimes alimentares num arranjo fatorial 2 × 2 × 3 totalmente aleatório com 3 repetições de 15 aves em períodos de crescimento (13 a 26 dias) e terminação (27 a 42 dias) e 120, 220 e 320 mEq kg-1 DAE. Além disso, 21% de PB aumentou o ganho de peso corporal (GPC) e diminuiu a conversão alimentar (CAR) no período de crescimento (p < 0.05). Por outro lado, 20% de PB diminuiu GPC e aumentou CAR no período terminal (p < 0.05). O nível de 20% PB reduziu o sódio sanguíneo e o balanço eletrolítico sanguíneo (p < 0.05). O maior balanço eletrolítico sanguíneo ocorreu com DAE 320 mEq kg-1 dieta (p < 0.05). A resposta das aves de corte a DAE no estresse calórico dependia da idade da ave, à exposição a altas temperaturas e ao nível de PB na dieta. Sob estresse calórico (29-34°C), 21% PB no período de crescimento e 17% de PB no período de terminação melhoraram o GPC e CAR das aves de corte.

ABSTRACT The effect of crude protein (CP), amino acid (AA), and dietary electrolyte balance (DEB) were evaluated on blood parameters, carcass traits, and broiler performance under heat stress (29-34°C). A total of 540 male chickens (Ross 308) were allocated to 12 diets with factorial arrangement 2 × 2 × 3, using a completely randomized design with three replicates of 15 chickens in grower (13 to 26 days) and finisher (27 to 42 days) periods. and 120, 220, and 320 mEq kg-1 DEB. The level of 21% CP increased body weight gain (BWG) and decreased feed conversion ratio (FCR) at grower period (p < 0.05). In contrast, 20% CP level decreased BWG and increased FCR at finisher period (p < 0.05). Further, 20% CP level reduced blood sodium and blood electrolyte balance (p < 0.05). The highest blood electrolyte balance was achieved by DEB 320 mEq kg-1 diet (p < 0.05). Broiler response to DEB in heat stress depended on the age of bird, length of exposure to high temperature and CP level of the diet. Under heat stress (29-34°C), the 21% CP level at grower period and 17% CP level at finisher period improved broiler BWG and FCR.