Rafanan K Clerre, Herrera Michelle J, Catabay Caitlyn, German Donovan P
Department of Ecology & Evolutionary Biology, University of California, Irvine, CA, 92697-2525, USA.
Department of Biological Sciences, California State University, Fullerton, CA, 92831, USA.
Fish Physiol Biochem. 2025 Sep 18;51(5):166. doi: 10.1007/s10695-025-01567-y.
Digestion is primarily performed by digestive enzymes. Here, we examined the activity levels of seven digestive enzymes along the digestive tract of the herbivorous fish, Cebidichthys violaceus. We reared C. violaceus on carnivore, omnivore, and herbivore diets in the laboratory for nine months and compared the digestive enzyme activities among the fish on the different diets and with wild-caught fish consuming their natural foods. Enzymatic activities were generally lower in the laboratory than in wild-caught fish. The marked anterior-to-posterior amylase activity gradient along the gut in wild-caught fish was absent in the lab-fed fish. We hypothesize that the dampened enzymatic activity may have been caused by reduced food intake in the laboratory in comparison to the wild fish. N-acetyl-β-D-glucosaminidase (NAGase) activity (degrades chitin breakdown products) peaked in the distal intestines of the lab-fed fish, but not the wild fish. The role of this enzyme in the digestive process remains unknown since the lab diets contained no chitin, and its origin may have been microbial. Overall, C. violaceus can tolerate diets with a wide range of protein and carbohydrate levels. However, the totality of our data suggests that live algal diets may be best for this herbivorous fish in a captive setting, especially for aquaculture.
消化主要由消化酶完成。在此，我们检测了草食性鱼类紫拟鲈消化道中七种消化酶的活性水平。我们在实验室中用肉食性、杂食性和草食性饲料饲养紫拟鲈九个月，并比较了不同饲料喂养的鱼以及食用天然食物的野生捕获鱼之间的消化酶活性。实验室饲养的鱼的酶活性通常低于野生捕获的鱼。野生捕获的鱼肠道中沿肠道明显的从前到后的淀粉酶活性梯度在实验室喂养的鱼中不存在。我们推测，与野生鱼相比，实验室中酶活性降低可能是由于食物摄入量减少所致。N - 乙酰 - β - D - 氨基葡萄糖苷酶（NAGase）活性（降解几丁质分解产物）在实验室喂养的鱼的远端肠道中达到峰值，但在野生鱼中未出现。由于实验室饲料中不含几丁质，该酶在消化过程中的作用尚不清楚，其来源可能是微生物。总体而言，紫拟鲈能够耐受蛋白质和碳水化合物水平范围广泛的饲料。然而，我们所有的数据表明，在圈养环境中，特别是对于水产养殖来说，活藻饲料可能最适合这种草食性鱼类。
