Lundstedt L M, Melo José Fernando Bibiano, Moraes Gilberto
Department of Genetics and Evolution, Federal University of São Carlos, Rod. Washington Luís, km 235 CEP: 13565-905 CP 676. São Carlos, SP, Brazil.
Comp Biochem Physiol B Biochem Mol Biol. 2004 Mar;137(3):331-9. doi: 10.1016/j.cbpc.2003.12.003.
Digestive enzyme responsiveness to feeding and associated adjustments of metabolism can be used to derive nutritionally effective diet formulations. Juvenile pintado (Pseudoplatystoma corruscans) were fed different diets. After feeding, fish were killed and blood, liver and white muscle were collected to evaluate metabolites. Stomach along with anterior, middle and posterior intestine were sampled for enzyme analysis. Non-specific protease, trypsin, chymotrypsin, amylase and lipase were assayed. Crude protein (CP) did not induce proteolytic activity; highest protease activities were observed in the stomach. Amylase was higher in the stomach in fish feeding on diets containing 13-25% starch. Lipase activity was observed along the gastrointestinal tract, with the highest activities observed in the middle section. The metabolic profile of white muscle was not affected by CP. In contrast, some plasma and liver metabolites were altered concomitant with changes in the digestive enzymes. Amino acid catabolism was increased. Digestion in pintado was responsive to cornstarch, reflected in intermediary metabolism; proteolytic activities of the digestive tract seem to be sufficient to deal with large amounts of dietary protein. As a result, we are able to recommend a balance between protein and energetic compounds, such as lipids and carbohydrates, in the diet to optimize fish growth.
消化酶对摄食的反应以及相关的代谢调整可用于推导营养有效的日粮配方。给幼年巴西真鲷（Pseudoplatystoma corruscans）投喂不同的日粮。投喂后，处死鱼并采集血液、肝脏和白色肌肉以评估代谢产物。采集胃以及前肠、中肠和后肠进行酶分析。检测了非特异性蛋白酶、胰蛋白酶、糜蛋白酶、淀粉酶和脂肪酶。粗蛋白（CP）未诱导蛋白水解活性；在胃中观察到最高的蛋白酶活性。在以含有13 - 25%淀粉的日粮喂养的鱼中，胃中的淀粉酶含量较高。沿胃肠道均观察到脂肪酶活性，在中间部分观察到最高活性。白色肌肉的代谢特征不受CP的影响。相反，一些血浆和肝脏代谢产物随着消化酶的变化而改变。氨基酸分解代谢增加。巴西真鲷的消化对玉米淀粉有反应，这反映在中间代谢中；消化道的蛋白水解活性似乎足以处理大量的日粮蛋白质。因此，我们能够推荐日粮中蛋白质与能量化合物（如脂质和碳水化合物）之间的平衡，以优化鱼类生长。
