Corrêa Cristina Ferro, de Aguiar Lúcia Helena, Lundstedt Lícia Maria, Moraes Gilberto
Department of Genetics and Evolution, Federal University of Sao Carlos, Rod. Washington Luís Km 235, CP 676, Sao Carlos, SP, CEP 13565-905 Brazil.
Comp Biochem Physiol A Mol Integr Physiol. 2007 Aug;147(4):857-62. doi: 10.1016/j.cbpa.2006.12.045. Epub 2007 Apr 12.
Digestive enzyme responses plus metabolic implications were studied in tambaqui (Colossoma macropomum) fed isoproteic diets containing 28% crude protein, 3300 kcal of gross energy/kg and different amounts of cornstarch (30, 40 and 50%). Amylase, maltase, acid protease, trypsin and chymotrypsin from the alimentary tract were assayed. Plasma, liver and white muscle metabolites were gauged to profile metabolism of the fish. The alimentary tract of tambaqui is compartmentalized morphologically and enzymatically. Amylase was present through the gut; acid protease was detected in stomach; maltase, trypsin and chymotrypsin were found in pyloric caeca and proximal and distal intestine sections. Increase of cornstarch levels from 40 to 50% in the diet resulted in an increase in amylase and maltase. Trypsin and chymotrypsin were unresponsive to starch levels. Acid protease follows the protein/carbohydrate ratio decrease. The increase of dietary cornstarch resulted in liver glycogenesis and the increase in plasma triglycerides is suggestive of lipogenesis. Digestive biochemical responses of tambaqui correlated with changes of feeding plus the analyses of metabolic profile are assumed as a tool for optimizing diet formulation and are a clue to other feeding optimizations for freshwater tropical species.
研究了投喂含28%粗蛋白、3300千卡总能/千克且玉米淀粉含量不同（30%、40%和50%）的等蛋白日粮的 tambaqui（巨脂鲤）的消化酶反应及其代谢影响。测定了消化道中的淀粉酶、麦芽糖酶、酸性蛋白酶、胰蛋白酶和糜蛋白酶。检测了血浆、肝脏和白色肌肉中的代谢物以描绘该鱼的代谢情况。tambaqui的消化道在形态和酶方面存在分区。整个肠道均存在淀粉酶；在胃中检测到酸性蛋白酶；在幽门盲囊以及近端和远端肠道段发现了麦芽糖酶、胰蛋白酶和糜蛋白酶。日粮中玉米淀粉水平从40%增加到50%会导致淀粉酶和麦芽糖酶增加。胰蛋白酶和糜蛋白酶对淀粉水平无反应。酸性蛋白酶随蛋白质/碳水化合物比例降低而变化。日粮中玉米淀粉的增加导致肝脏糖原生成，血浆甘油三酯增加表明有脂肪生成。tambaqui的消化生化反应与摄食变化相关，代谢特征分析被视为优化日粮配方的工具，也是淡水热带物种其他摄食优化的线索。
