Avaliação do desempenho de coelhas submetidas a diferentes níveis energéticos e períodos de lactação e de coelhos em crescimento alimentados com diferentes perfis de nutrientes

• Ano de defesa: 2006
• Autor(a) principal: Silva, Waldirene Rossi da
• Tipo de documento: Dissertação
• Tipo de acesso: Acesso aberto
• Idioma: por
• Instituição de defesa: Universidade Estadual de Maringá; Brasil; Programa de Pós-Graduação em Zootecnia; UEM; Maringá, PR; Centro de Ciências Agrárias
• Palavras-chave em Português: Coelhas; Níveis de energia; Digestibilidade; Reprodução e produção; Desempenho; Carcaça; Qualidade; Brasil.; Rabbits; Energy levels; Digestibility; Reproduction and production; Performance; Housing; Quality; Brazil.; Ciências Agrárias; Zootecnia
• Link de acesso: http://repositorio.uem.br:8080/jspui/handle/1/1669

Three experiments were performed with the aim to evaluate the effects of two dietary levels of Digestible Energy (DE) (2600 and 2800 kg DE/kg) and two weaning ages (28 or 35 days) on productive and reproductive performance of female rabbits and carcass fatty acids profile and performance of rabbits descended from females fed to different levels of energy, receiving diets with two levels of starch (16% or 21%), with or without soybean oil addition, from weaning to slaughter. In order to study the reproductive and productive performance of female rabbits, 80 White New Zealand rabbits aging five months old initialy were used during three reproductive cycles. The animals were allocated in a completely randomized design with a factorial scheme 2x2x3 (2600 and 2800 kcal DE/kg of ration versus weaning at 28 and 35 days old versus three reproductive cycles), with 20 replications. Live weight data were collected at the beginning of the trial, each covering, birth and weaning (28 or 35 days). It was also collected data about litter size and weight at three moments (birth, 21 days old and weaning) and ration intake during the different phases of reproduction. For the reproductive characteristics that were evaluated in this work, it was observed that, along the reproductive sequence, the number of coverings for each pregnancy was reduced (P<0,05), and the litter size and live weight at birth was increased. Litter weight at 21 days old was higher (P>0,05) for females fed to ration with the energetic level of 2800 kcal DE/kg and also the sequence of reproductive cycles showed effects on this characteristic after the second cycle. Litters weaned at 35 days old showed higher weight. The weight of females which have weaned their young rabbits at 28 days old was higher (P<0,05) in the first and in the second cycles, but no effect was observed in the third one. The fertility rate was higher for females that weaned their litter at 35 days old. In order to evaluate the performance of rabbits from weaning to slaughter, 240 litters descended from females which were submitted to different dietary levels of energy and weaning age. Animals were allocated in a completely randomized design with a factorial scheme 2x2x2x3 (2600 and 2800 kcal DE/kg until weaning versus weaning at 28 and 35 days versus diets with high or low starch level (21% or 16%) versus three birth sequences), with 10 replications. Animals were weighed at weaning, 50 days old and at slaughter (70 days old). Evaluations about ration intake, daily weight gain, feeding conversion, carcass characteristics and ration cost per kilogram of gained live weight were performed. Animals that descended from females which were fed to less energetic diets (2600 kcal DE/kg of ration) until weaning showed greater weight gain at 50 days old (P<0,05), but this characteristic was not affected at 70 days of age; these animals also presented a better feed conversion from weaning to 50 days of age. Animals weaned at 35 days old showed higher weight at weaning, but weaning at 28 days provided greater weight gain (P<0,05) from 50 to 70 days old. The sequence of reproductive cycles improved (P<0,05) the animals weight at slaughter and weight gain from weaning to slaughter. The ration with lower level of starch and soybean oil addition fed to animals after weaning provided a higher intake (P<0,05) from weaning until 50 days old, which increased the cost per kg of live weight during the period of evaluation. Animals descended from females which have eaten lower levels of digestible energy before weaning presented heavier carcasses. It was observed that lower level of starch on diets post-weaning provided heavier kidneys, and at the same time, the sequence of reproductive cycles also raised the weight of the liver and kidneys as well. For the evaluation of the fatty acid profile of carcasses from rabbits fed to different levels of starch (16% or 21%) with or without soybean oil addition on diets, 32 animals that descended from females which were submitted to different levels of dietary energy and litter weaning age were used. Animals were allocated in a completely randomized experimental design with a factorial scheme 2x2x2 (2600 and 2800 kcal DE until weaning versus weaning at 28 and 35 days versus diets with high or low level of starch (21% or 16%). After slaughter at 70 days old, the right thigh from each animal was collected, then packaged in plastic bags and stored in the freezer for further analyses. After defrosting, the meat was grinded and submitted to lipidic extraction. The transesterification of triacylglicerols from the samples was done, then a chromatographic analysis took place. The peak areas were determinated in a CG-300 equipment and the identification of the major peaks was done by comparison of retention times with the metilic esteres standards of fatty acids from Sigma (EUA). For qualitative characteristics of rabbit carcass, it was observed that the ration with soybean oil provided carcasses with lower values of saturated fatty acids, so the profile of fatty acids in meat reflected the composition of experimental diets.