Exigência de metionina + cistina em dietas de patos (cairina moschata domesticus) em confinamento

Abstract

The present study aimed to determine ideal levels of total methionine + cystine for muscovy ducks in housing. Two hundred and forty muscovy ducks of creole strain were used, distributed in boxes with water and food ad libitum. The experimental design was completely randomized with treatments consisting of six nutritional plans that included the initial, growth and termination stages and differed levels of total methionine + cystine, and four replicates of 10 muscovy ducks each. The birds had weekly performance evaluations, and after 90 days, eight birds (four males and four females) in each treatment were slaughtered for evaluation of carcass traits. Data collected were subjected to Tukey test at 5% of significance. Differences were observed (p<0.05) in all performance variables analyzed. The nutritional plan 3 providing a reduction on feed intake, and an increase on weight gain, causing a significant effect on feed conversion. Levels above and below this requirement caused a significant loss on bird performance. Differences (p<0.05) were observed in all carcass traits variables among nutritional plans and sexes. Birds fed nutritional plan 3 presented better carcass results. There was a great difference in the carcass development among sexes, where male muscovy ducks presented better results. It was concluded that the nutritional plan 3 (Initial: 0.90% of Met+Cys; Growth: 0.80 of Met+Cys; and Termination: 0.70 of Met+Cys) presented ideal requirement of total methionine + cystine for muscovy ducks in housing, with better performance and carcass development.