Suplementação de colina em dietas para frangos de corte machos em fase de crescimento / Choline supplementation in diets for male broilers in the growing phase

Avaliaram-se os efeitos dos níveis de suplementação de colina em dietas para frangos de corte, de 22 a 40 dias de idade, sobre o desempenho, a composição de carcaças e fígados, bem como as características macroscópicas e histopatológicas dos fígados. O período de criação foi de um a 40 dias de idade, sendo que o período experimental foi de 22 a 40 dias de idade. Até o 21º dia de idade, todas as aves receberam a mesma ração à qual foram adicionados 400mg colina/kg. No 22º dia, os frangos foram distribuídos em cinco tratamentos, nos quais os níveis testados de suplementação de colina foram: zero, 400, 800, 1.200 e 1.600mg/kg, com seis repetições de 30 aves cada. As rações experimentais, formuladas à base de milho, farelo de soja e farinha de carne/ossos, foram isonutritivas, com exceção dos níveis de colina. O delineamento experimental foi o inteiramente ao acaso, e a estimativa da suplementação de colina foi avaliada pelos modelos de regressão. Os níveis de suplementação de colina apresentaram efeito linear pelo teste F (P<0,05) para o consumo de ração. Os demais parâmetros avaliados não sofreram influência da suplementação (P>0,05). O nível de 1.600mg colina/kg de ração resulta em maior consumo de ração de frangos de corte aos 40 dias de idade.

The effects of choline supplemental levels were evaluated in diets for broilers on performance, carcass and liver composition and liver histopathology characteristics from 22 to 40 days-old. The period of creation was one to 40 days of age, and the experimental period was 22 to 40 days-old. Until 21 days of age all birds received the same diet added to 400mg choline/kg. On day 22, broilers were allotted to five treatments (zero, 400, 800, 1200 and 1600 mg/kg), with six repetitions of 30 birds each. The experimental diets formulated based on corn, soybean meal and meat/bones meal were isonutritive, except for the choline levels. The experimental design was completely randomized and the estimation of choline supplementation was evaluated by regression models. The levels of choline supplementation showed a significant linear effect for the F test (P<0.05) for feed intake. The other evaluated parameters were not influenced by supplementation (P>0.05). The supplementation of 1600mg choline/kg in the diet results in higher feed intake of broilers at 40 days old.

Efeitos do horário de postura de matrizes pesadas sobre o rendimento de incubação / Effects of oviposition time from broiler breeders on the incubation yield

The effects of oviposition time, which represents different positions of the follicles in a sequence of posture, were studied on egg weight, chick weight, egg weight loss during incubation, hatchability, embryo mortality and infertility . A total of 19, 820 eggs, layed on the same day, from Cobb® broiler breeders aging 46-week-old were used. The eggs were classified according to the oviposition time posture (corresponding to the time of collection) from 8:30 am, 10:30 am, 12:30 pm, 14:30 pm and 16:30 pm, which represented the folowing treatments: 1st, 2nd, 3rd, 4th and 5th collects, respectively. The experimental design was completely randomized with five treatments and 36 repetitions, and each tray of 96 eggs was considered a repetition. The normal and homogeneous data were submitted to analysis of variance and means compared by Tukey test. The non-normal and non-homogeneous averages were compared by Kruskal-Wallis test. It is concluded that the time of egg laying has influence on egg weight and chick weight, but does not affect hatchability, fertility and embryonic development.

Efeito do armazenamento e da cantaxantina dietética sobre a qualidade do ovo fértil e o desenvolvimento embrionário / The effect of storage and dietary canthaxanthin on fertile egg quality and embryonic development

O presente experimento foi conduzido em lote de matrizes Cobb desde 46 até 60 semanas de idade. Os tratamentos foram definidos pelas dietas (com e sem adição de 6ppm de cantaxantina na dieta das matrizes) e pelos períodos de armazenamento dos ovos (três e sete dias), em delineamento inteiramente ao acaso, em arranjo fatorial 2x2 (duas dietas x dois períodos de armazenamento). A cantaxantina dietética elevou o escore de cor da gema de sete para 14. O armazenamento dos ovos por sete dias prejudicou a qualidade dos ovos, promoveu oxidação de ácidos graxos da gema e retardou o desenvolvimento embrionário.

This trial was done with Cobb broiler breeders. Treatments were defined by the diets (with and without 6ppm canthaxanthin added to broiler breeder diets) and periods of egg storage (three and seven days) in a completely randomized factorial 2 x 2 design (two diets x two periods of egg storage). The dietary canthaxanthin increased the yolk color score from 7 to 14. Egg storage for seven days reduced egg quality, promoted oxidation of yolk fatty acids and delayed embryonic development.