科研之友
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摘要
Em estudos realizados com varia o no teor de prote赤na na ra o para peixes, foi demonstrado o aumento das atividades de protease alcalina, protease 芍cida, tripsina e quimiotripsina do trato digest車rio de jundi芍 (Rhamdia quelen). Esses fatos sugerem que produtos liberados pela digest o na luz desse trato podem influenciar a s赤ntese e a secre o de enzimas digestivas. A secre o destas enzimas pelo pancreas, em vertebrados, responde 角 influ那ncia neurale humoral. No presente trabalho, foram testadas quatro concentra es (0, 3, 6 e 12%) de uma mistura de amino芍cidos (treonina, fenilalanina, leucina, valina, arginina e triptofano em iguaispropor es) em dietas isocal車ricas contendo 3.500 kcal de energia digest赤vel kg-1 de ra o, e dietas isoproteicas contendo 20% de prote赤na, em juvenis de jundi芍. Foram utilizados dez animais portratamento, sendo os peixes estocados num sistema fechado com recircula o de 芍gua e temperatura controlada. Os peixes submetidos a estes tratamentos apresentaram atividade da protease alcalina na regi o anterior do intestino, responsiva aos diferentes n赤veis amino芍cidos da alimenta o. Todavia, as atividades protease alcalina do f赤gado e amilase do f赤gado e intestino anterior n o foram detectadas. Estes resultados sugerem que a atividade protease alcalina do intestino anterior seja induzida por amino芍cidos liberados na luz do trato digest車rio. Studies carried out with variation of protein concentration in the fish feed have shown an increase in the activity of alkaline proteases, acid proteases, trypsin and chimotrypsin from the digestive tract of silver catfish (Rhamdia quelen). These facts suggest that products released by digestion in the lumen of this tract can influenced the synthesis and secretion of digestive enzymes. The secretion of these enzymes by the pancreas in vertebrate responses to neural and humoral influences. In the present study, four concentration (0, 3, 6 and 12%) of an amino acid mix(threonine, phenylalanine, leucine, valine, arginine and thryptophan, in equal amounts) were tested in isocaloric (3500 kcal of digestible energy kg-1 of feed) and isoproteic (20% of protein) diets on juveniles of silver catfish. It was used 10 specimens per treatment stocked in a water recirculation system, with controlled and constant temperature. The fish submitted to the treatments presented alkaline activity in the anterior region of the gut, responding to thedifferent levels of amino acid in the feed. Although there was alkaline proteases activity in the liver, the amylase activity of the liver and anterior gut was not obser
