Department of Ecology and Evolutionary Biology, University of California, Irvine, 321 Steinhaus Hall, Irvine, CA 92697, USA.
Department of Ecology and Evolutionary Biology, University of California, Irvine, 321 Steinhaus Hall, Irvine, CA 92697, USA.
Comp Biochem Physiol A Mol Integr Physiol. 2022 Aug;270:111230. doi: 10.1016/j.cbpa.2022.111230. Epub 2022 May 7.
Abalone around the world are subject to increasing frequency of marine heatwaves, yet we have a limited understanding of how acute high temperature events impact the physiology of these commercially and ecologically important species. This study examines the impact of a 5 °C temperature increase over ambient conditions for six weeks on the metabolic rates, digestive enzyme activities in the digestive gland, and digestive efficiency of Red Abalone (Haliotis rufescens) and Pāua (H. iris) on their natural diets. We test the hypothesis that abalone digestive function can keep pace with this increased metabolic demand in two separate experiments, one for each species. H. iris had higher food intake in the heat treatment. Both species had higher metabolic rates in the heat treatment with Q = 1.73 and Q = 2.46 for H. rufescens and H. iris, respectively. Apparent organic matter digestibility, protein digestibility, and carbohydrate digestibility did not differ between the heat treatment and the ambient (control) treatment in either experiment. H. rufescens exhibited higher maltase, alanine-aminopeptidase, and leucine-aminopeptidase activities in the heat treatment. Amylase, β-glucosidase, trypsin, and alkaline phosphatase activities in the digestive gland tissue did not differ between temperature treatments. H. iris exhibited lower amylase and β-glucosidase activities in the heat treatment, while maltase, trypsin, leucine-aminopeptidase, and alkaline phosphatase activities did not differ between treatments. We conclude that over six weeks of moderate heat stress both abalone species were able to maintain digestive function, but achieved this maintenance in species-specific ways.
世界各地的鲍鱼都面临着海洋热浪发生频率增加的问题，但我们对急性高温事件如何影响这些具有商业和生态重要性的物种的生理机能知之甚少。本研究考察了在六周的时间内，将环境温度升高 5°C 对红鲍（Haliotis rufescens）和帕瓦（H. iris）的代谢率、消化腺中消化酶活性和消化效率的影响，这两种鲍鱼都食用其天然食物。我们通过两个独立的实验来检验鲍鱼的消化功能是否能够跟上这种代谢需求增加的假设，每个实验针对一种鲍鱼。在高温处理中，H. iris 的食物摄入量更高。在高温处理中，两种鲍鱼的代谢率都更高，Q 值分别为 1.73 和 2.46。在两个实验中，高温处理和环境（对照）处理之间的表观有机物消化率、蛋白质消化率和碳水化合物消化率没有差异。在高温处理中，H. rufescens 的麦芽糖酶、丙氨酸氨肽酶和亮氨酸氨肽酶活性更高。在消化腺组织中，淀粉酶、β-葡萄糖苷酶、胰蛋白酶和碱性磷酸酶的活性在温度处理之间没有差异。在高温处理中，H. iris 的淀粉酶和β-葡萄糖苷酶活性较低，而麦芽糖酶、胰蛋白酶、亮氨酸氨肽酶和碱性磷酸酶的活性在处理之间没有差异。我们的结论是，在六周的适度热应激中，两种鲍鱼都能够维持消化功能，但它们以特定物种的方式来维持这种功能。
