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An experiment was conducted to investigate the development of the digestive system in slow-growing broilers of different strains. The experiment involved a total of 544 one-day-old chicks, 136 of each of four genotypes, namely, Label Rouge Pesadão, Label Rouge Pescoço Pelado, Carijó and Carijó Pescoço Pelado. The birds were distributed in a completely randomized design with four treatments (genotypes) and eight replicates of 17 animals each. Live weight, digestive tract development and intestinal histomorphometric measurements were evaluated at different ages. Significant differences (p < 0.05) were observed between the strains for live weight, relative weight and length of digestive tract organs and intestinal histomorphometric measurements at one, seven and 28 days of age. The Carijó strain showed greater weight and development of digestive organs than the Carijó Pescoço Pelado strain. There was a difference (p < 0.05) for histomorphometric measurements of the small intestine between the strains at the evaluated ages. The Carijó Pescoço Pelado and Label Rouge Pescoço Pelado strains showed higher villi and higher villus:crypt ratios in the duodenum, jejunum and ileum. The slow-growing strains differ in performance regarding the relative weights and lengths of digestive tract organs and intestinal histomorphometric measurements. Um experimento foi realizado com o objetivo de avaliar o desenvolvimento do sistema digestório em frangos de corte de crescimento lento de diferentes linhagens. Foram utilizados 544 pintos com um dia de idade, sendo 136 de cada genótipo sendo: Label Rouge Pesadão, Label Rouge Pescoço Pelado, Carijó e Carijó Pescoço Pelado. Distribuídos em um delineamento inteiramente casualizado com quatro tratamentos (genótipo) e oito repetições de 17 animais cada. As variáveis estudadas foram peso vivo, desenvolvimento do trato digestório e medidas histomorfométricas intestinal em diferentes idades. Houve diferença (p < 0,05) entre as linhagens no peso vivo, peso relativo e comprimento dos órgãos do trato digestório e medidas histomorfométricas intestinal com um, sete e 28 dias de idade. A linhagem Carijó apresentou maior peso e desenvolvimento de órgãos digestórios comparada a linhagem Carijó Pescoço Pelado. Houve diferença (p < 0,05) para medidas histomorfométricas do intestino delgado entre as linhagens nas idades avaliadas. As linhagens Carijó Pescoço Pelado e Label Rouge Pescoço Pelado apresentaram maior altura de vilo e relação vilo:cripta do duodeno, jejuno e íleo. As linhagens de crescimento lento apresentam diferenças entre si no desempenho peso relativo e comprimento de órgãos do trato digestório e nas medidas histomorfometricas do intestino.

The present study aimed to ascertain the effects of slow-growing breeder age on embryo development, incubation results, and chick quality and of the interaction between breeder age and hatching time on initial performance. A total of 630 hatching eggs obtained from a commercial flock of slow-growing broiler breeders (Isa Label Naked Neck) were evaluated in 2 experiments. The first experiment evaluated embryo development and hatching results for broiler breeder age treatments of 38 and 51 wk, whereas the second experiment evaluated broiler chick performance. For the second experiment, chicks were distributed in a 2 x 2 factorial randomized block (sex) experimental design consisting of 2 breeder ages (31 or 58 wk) and 2 hatching times (479–485 and 491–497 h). At 18 d of embryonic development, embryos of 51-wk-old breeders were larger than those of 38-wk-old breeders (P 0.05). Embryo organ weight was similar for the 2 breeder ages (P > 0.05); however, there was greater development of intestinal villi for embryos of the 51-wk-old breeders. There were no differences between breeder ages in hatchability and chick quality score (P > 0.05). Yolk-free chick weight at pulling was greater (P 0.05); however, chicks hatching at 491–497 h had better performance from 1 to 28 d than did chicks hatching at 479–485 h (P

Fish oil is used as a supplement in animal feed and is recognized for its positive effects on human health. This work evaluated the fatty acid composition and the nutritional quality of the lipid fraction of Nile tilapia fillets (Oreochromis niloticus) that were supplemented with different levels of fish oil (0% (control group), 5%, 10%, or 15% diet in addition to the ether extract of the commercial formulation) for 30 and 60 days pre-slaughter. The effective treatments were 4.61, 9.22, and 13.83% ether extract based on dry matter, respectively. The influence of hyperlipidic diets on the biometric indexes, the variables of weight and body income analyzed was not verified. The effects of oil level and treatment duration were determined by contrast analysis. Thirty-three fatty acids were identified in fillet, with a predominance of oleic (C18:1n-9), palmitic (C16:0), linoleic (C18:2n-6), and stearic (C18:0) acids. Experimental diets significantly influenced the content of fatty acids, particularly eicosapentaenoic acid (C20:5n-3), docosahexaenoic acid (C22:6n-3) and n-3 docosapentaenoic acid (C22:5n-3). Fish oil supplementation showed lower n-6/n-3 ratios and higher polyunsaturated fatty acids/saturated fatty acids ratios compared with the control, contributing to a reduction in thrombogenic index in the sampled fillets. The experimental diets had no effect on the atherogenic index. Comparison of the duration of treatments (30 days vs. 60 days) demonstrated that the total n-6 fatty acids, n-6/n-3 ratio, and contents of docosapentaenoic acid (C22:5n-6) in fillet decreased with extension of the supplementation time. We conclude that fish oil added to tilapia feed nutritionally enriches the fish fillets and it is a good option for commercial production.