ABSTRACT An experiment was performed to evaluate the effect of the incubation system ― multiple-stage (MS) and single-stage (SS) ― on the characteristics at hatching, intestinal morphology, metabolism, and performance of Cobb-500 chickens from 1 to 40 d of age. A total of 1,968 fertile eggs were incubated in two setters under commercial conditions. Birds hatched in SS were longer than those hatched in MS, and the females had higher relative intestinal weight compared with males. However, at hatching, there were no differences in BW and yolk-free body mass from incubation system or sex. In the period from 1-40 d, the birds hatched in SS were heavier, had higher weight gain and better adjusted feed conversion, without differences in feed intake and feed conversion. This result is due mainly to MS females, which always, although in some periods only numerically, exhibited worse responses than the other treatment, lowering the average MS bird performance. Sex influenced the duodenal villi height in chickens at 0 d; females showed larger villi than males. Moreover, the birds hatched in SS had deeper crypts than those hatched in MS. At 7 d, because males had higher feed intake, the differences in duodenal villi height found at hatching disappeared, leaving only a gender effect on jejunum crypt depth: females showed deeper crypts. As regards the metabolism coefficients of nutrients from 5 to 7 d, females were more efficient in metabolizing energy and showed higher apparent metabolizable energy corrected for nitrogen values than males, with no differences caused by the incubation system. The best incubation conditions are obtained with the single-stage system, based on the improved broiler performance (2.98%), especially in the females (5.04%).

RESUMO Estudou-se a via de fornecimento de cloreto de sódio (NaCl) – água ou ração – sobre o desempenho de frangos de corte, consumo de água, desenvolvimento dos órgãos, metabolizabilidade da matéria seca (MMS), retenção de nitrogênio (RN), energia metabolizável aparente corrigida para nitrogênio (EMAn), matéria seca das excretas (MSex) e composição de carcaça. Foram utilizados 120 frangos da linhagem Ross 308, distribuídos em três tratamentos com quatro repetições de 10 aves cada, num delineamento completamente casualizado. De um a sete dias de idade foram submetidos a três formas de suplementação de NaCl (0,47% de Na): 100% na ração; 50% na ração e 50% na água (50% ração:50% água); e 100% na água. Durante o período de oito a 21 dias as aves receberam uma dieta única, com NaCl via ração. De um a sete dias não houve diferença no Consumo de Água, Consumo de Ração e Ganho de Peso; porém, NaCl via água proporcionou melhor CA do que por ambas as vias (p < 0,07). Aos 21 dias de idade não foram observadas diferenças significativas no desempenho, no peso relativo do coração, fígado e moela e no comprimento relativo do intestino. Não houve resposta à via de fornecimento para EMAn e MSex em pintos de quatro a sete dias de idade; no entanto, as aves que receberam o NaCl via água de bebida, exibiram menor MMS e RN (p < 0,05) no mesmo período. Conclui-se que o NaCl pode ser adicionado tanto na ração quanto na água, sem ocasionar prejuízos ao desempenho produtivo dos frangos de corte na fase pré-inicial.

SUMMARY It was investigated the way to provide NaCl -by water or feed- on performance, water intake, organs development, dry matter metabolizability (DMM), nitrogen retention (NR), apparent metabolizable energy corrected for nitrogen (AMEn), dry matter of excreta (DMEx) and carcass composition (CC) of broilers. One hundred twenty one-day-old male Ross 308 distributed in three treatments with four replications of ten birds each, in a completely randomized design, were subjected to three ways to supply NaCl (0.47% of Na): 100% in diet, 50% in diet and 50% in water (50:50), and 100% in water during the pre-starter period (one to seven days). During the starter period (eight to 21 days) the birds received a unique diet, with NaCl in diet. From one to seven days, there were no significant differences on water intake, feed intake and weight gain; but NaCl in water provided better feed conversion than in both ways (p < 0.07). At 21 d, there were no significant differences in performance, relative weight of heart, liver and gizzard, and relative length of intestine. There was no response to supply way for AMEn and DMEx in chicks from four to seven days; however, birds receiving NaCl via drinking water, exhibited lesser DMM and NR (P < 0.05) in the same period. It was concluded that NaCl can be added in both feed and water to pre-starter chicks.

Trata-se de um estudo de metabolizabilidade em frangos de corte Cobb, para testar os benefícios do processamento térmico por infravermelho no farelo de arroz integral (FAI) em diferentes tempos (0, 6, 8 e 10min). O experimento foi realizado através do método de substituição, em que 20% de uma dieta referência (DR) a base de milho e farelo de soja foi substituída pelos FAIs processados em diferentes tempos. Usou-se um delineamento experimental completamente casualizado com 5 tratamentos e 10 repetições de uma ave. Entre 21 e 28 dias de idade das aves, foi feita a coleta total de excretas, com 4 dias de adaptação às dietas e 3 de coleta. A dieta com FAI 6min teve melhor aproveitamento em relação às demais e foi a única que não piorou os coeficientes de metabolizabilidade em relação à DR. Na comparação da metabolizabilidade dos ingredientes isolados, não houve diferenças estatísticas. Porém, conforme aumentou o tempo de processamento, diminuiu a solubilidade e a metabolizabilidade da proteína. O processamento térmico por infravermelho não foi capaz de melhorar a metabolizabilidade do FAI para frangos de corte.

This is a study of metabolizability in broilers Cobb, to test rice bran infrared (RB) thermal processed at different times (0, 6, 8 and 10min). It was used a reference diet (RD) based on corn and soybean in which 20% of RB was included. The experiment design was completely randomized, with 5 treatments and 10 replicates. Each replicate was a 21 day old bird. After 4 days of diet adaptation, total excreta was collected, during 3 subsequent days. Diet with RB processed at 6 was better used than the others, the only one that did not differ from RD. Comparing RB processing times, there were no significant difference between them, regarding digestibility. Processing time was negatively related to protein solubility and protein metabolizability. Infrared heat processing was not able to improve FAI metabolizability for broilers.