College of Food and Pharmaceutical Sciences, Ningbo University, Ningbo, Zhejiang 315211, China; Li Dak Sum Yip Yio Chin Kenneth Li Marine Biopharmaceutical Research Center, Ningbo University, Ningbo 315211, China.
School of Marine Science, Ningbo University, Ningbo, Zhejiang 315211, China; Li Dak Sum Yip Yio Chin Kenneth Li Marine Biopharmaceutical Research Center, Ningbo University, Ningbo 315211, China.
Harmful Algae. 2023 Jun;125:102422. doi: 10.1016/j.hal.2023.102422. Epub 2023 Mar 11.
Phytoplankton composition is an important factor affecting the growth and physiological biochemical characteristics of filter-feeding bivalves. With the increasing trend in dinoflagellate biomass and blooms in mariculture areas, how the physio-biochemical traits and seafood quality of the mariculture organism are affected by the dinoflagellates, especially those at nonfatal levels, is not well understood. Different densities of two Karlodinium species, namely K. veneficum (KV) and K. zhouanum (KZ), mixed with high quality microalgal food Isochrysis galbana was applied in feeding manila clam Ruditapes philippinarum in a 14-day temporary culture, to comparatively study how the critical biochemical metabolites such as glycogen, free amino acids (FAAs), fatty acids (FAs), volatile organic compounds (VOCs) in the clam were affected. The survival rate of the clam showed dinoflagellate density and species specificity. The high-density KV group inhibited survival to 32% lower than that of the pure I. galbana control, respectively, while KZ at low concentrations did not significantly affect the survival compared with the control. In the high-density KV group, the glycogen and FAA contents decreased (p < 0.05), indicating that energy and protein metabolism were significantly affected. Amount of carnosine (49.91 ± 14.64 to 84.74 ± 8.59 μg/g of muscle wet weight) was detected in all the dinoflagellate-mixed groups, while it was not present in the field samples or in the pure I. galbana control, showing that carnosine participated in the anti-stress activities when the clam was exposed to the dinoflagellates. The global composition of FAs did not significantly vary among the groups. However, contents of the endogenous C PUFA precursors linoleic acid and α-linolenic acid significantly decreased in the high-density KV group compared to all the other groups, indicating that high density of KV affected the metabolisms of fatty acids. From the results of the changed VOC composition, oxidation of fatty acids and degradation of free amino acids might occur in the clams exposed to dinoflagellates. The increased VOCs, such as aldehydes, and decreased 1-octen-3-ol probably produced a more fishy taste and reduced food flavor quality when the clam was exposed to the dinoflagellates. This present study demonstrated that the biochemical metabolism and seafood qulity of the clam were affected. However, KZ with moderate density in the feed seemed to be beneficial in aquaculture for increasing the content of carnosine, a high-valued substance with multiple bioactivities.
浮游植物组成是影响滤食性双壳贝类生长和生理生化特性的重要因素。随着海洋养殖区甲藻生物量和赤潮的增加趋势，甲藻，特别是非致死水平的甲藻，如何影响养殖生物的生理生化特性和海鲜质量，目前还不太清楚。将两种卡氏藻，即卡氏膝沟藻（KV）和周氏卡氏藻（KZ），与高质量微藻饵料新月菱形藻混合，应用于菲律宾蛤仔（Ruditapes philippinarum）的 14 天临时养殖中，比较研究了贝类中关键生化代谢物如糖原、游离氨基酸（FAAs）、脂肪酸（FAs）、挥发性有机化合物（VOCs）的变化。蛤仔的存活率表现出甲藻密度和物种特异性。高浓度的 KV 组的存活率比纯新月菱形藻对照组低 32%，而低浓度的 KZ 与对照组相比，对存活率没有显著影响。在高浓度的 KV 组中，糖原和 FAA 含量降低（p < 0.05），表明能量和蛋白质代谢受到显著影响。在所有甲藻混合组中都检测到肌肽（49.91 ± 14.64 至 84.74 ± 8.59 μg/g 肌肉湿重），而在现场样本或纯新月菱形藻对照组中则未检测到肌肽，表明肌肽参与了蛤仔暴露于甲藻时的抗应激活动。各组之间的 FA 总组成没有显著差异。然而，与所有其他组相比，高浓度 KV 组内源性 C PUFA 前体亚油酸和α-亚麻酸的含量显著降低，表明高浓度的 KV 影响了脂肪酸的代谢。从变化的 VOC 组成结果来看，暴露于甲藻的蛤仔可能会发生脂肪酸氧化和游离氨基酸降解。增加的 VOC，如醛类，以及减少的 1-辛烯-3-醇，可能会在蛤仔暴露于甲藻时产生更鱼腥味的味道，并降低食物的风味质量。本研究表明，贝类的生化代谢和海鲜质量受到影响。然而，在饲料中添加适量密度的 KZ 似乎有利于水产养殖，因为它可以增加具有多种生物活性的高价值物质肌肽的含量。
