Pujante I M, Moyano F J, Martos-Sitcha J A, Mancera J M, Martínez-Rodríguez G
Departamento de Biología, Facultad de Ciencias del Mar y Ambientales, Campus de Excelencia Internacional del Mar (CEI·MAR), Universidad de Cádiz, 11519, Puerto Real, Cádiz, Spain.
Department of Biology, Faculty of Marine and Environmental Sciences, University of Cádiz, Avenida República Saharaui, 11510, Puerto Real, Cádiz, Spain.
Fish Physiol Biochem. 2018 Feb;44(1):349-373. doi: 10.1007/s10695-017-0440-6. Epub 2017 Nov 17.
The effects of different environmental salinities (0, 12, 40, and 55 ppt) on pepsinogen 2 (pga2), trypsinogen 2 (try2), chymotrypsinogen (ctr), and pancreatic alpha-amylase (amy2a) gene expression, and on the total activities of their corresponding enzymes, were assessed in Chelon labrosus juveniles, after their corresponding full-complementary DNA sequences were cloned. Furthermore, the quantitative effect of different salinities on the hydrolysis of feed protein by fish digestive enzymes was evaluated using an in vitro system. Relative pga2 expression levels were significantly higher in animals maintained at 12 ppt, while a significantly higher gene expression level for ctr and try2 was observed at 40 ppt. amy2a gene expression showed its maximum level at 40 ppt and the lowest at 55 ppt. A significant reduction in the activity of amylase with the increase in salinity was observed, whereas the maximum activity for alkaline proteases was observed in individuals maintained at 40 ppt. A negative effect of high salinity on the action of proteases was confirmed by the in vitro assay, indicating a decreased efficiency in the digestive function in C. labrosus when maintained at high environmental salinities. Nevertheless, individuals can live under different environmental salinities, even though gene expression is different and the enzymatic activities are not maintained at the highest studied salinity. Therefore, compensatory mechanisms should be in place. Results are discussed on the light of the importance as a new species for aquaculture.
在克隆了相应的全长互补DNA序列后，评估了不同环境盐度（0、12、40和55ppt）对皱唇鲨幼鱼胃蛋白酶原2（pga2）、胰蛋白酶原2（try2）、胰凝乳蛋白酶原（ctr）和胰腺α-淀粉酶（amy2a）基因表达及其相应酶总活性的影响。此外，使用体外系统评估了不同盐度对鱼类消化酶水解饲料蛋白的定量影响。维持在12ppt的动物中，pga2相对表达水平显著更高，而在40ppt时观察到ctr和try2的基因表达水平显著更高。amy2a基因表达在40ppt时达到最高水平，在55ppt时最低。随着盐度增加，淀粉酶活性显著降低，而在维持在40ppt的个体中观察到碱性蛋白酶的最大活性。体外试验证实了高盐度对蛋白酶作用的负面影响，表明在高环境盐度下饲养时，皱唇鲨的消化功能效率降低。然而，即使基因表达不同且酶活性在最高研究盐度下未维持，个体仍可在不同环境盐度下生存。因此，应该存在补偿机制。根据其作为水产养殖新物种的重要性对结果进行了讨论。
