鱼类早期发育阶段异速生长及核酸、消化酶变化的研究进展

鱼类早期发育阶段是其生活史中的关键时期之一,生理、形态学变化剧烈,死亡率极高。研究鱼类早期发育阶段的生长规律及其生理特性,可为了解鱼类早期阶段的致死因子提供理论依据,有助于提高苗种阶段的生长率和成活率,也对制定合理的早期培育策略具有重要的指导意义。异速生长模式对确定仔鱼的养殖模式有重要的指示作用,鱼类在早期阶段会优先发育与生命活动关系较密切的器官,以期达到较高的早期成活率。RNA/DNA是评价鱼类早期发育阶段生长率的有效指标,也可用于评价仔稚鱼的生长潜力、营养状况、饲料营养水平以及确定关键期。研究仔稚鱼消化酶的发生和演变有助于深入了解鱼类在个体发育早期的消化生理,有助于选择适口饵料和制定投喂策略。因此,本文综述了鱼类早期发育阶段的异速生长模式、核酸及蛋白含量变化规律以及消化酶的发生和变化,为鱼类早期阶段健康养殖的发展提供依据。

Allometric growth and ontogenetic changes in nucleic acids and digestive enzymes during the early life stage in fish species: A review

The early life stage is a critical period in fish species since complicated physiological and morphologi-cal changes and often massive mortalities occur at this stage. Studies of the growth patterns and physiological characteristics during the early life stage often uncover lethal factors in this stage, and the information gained can lead to improvements in survival rates during larval production. Allometric growth can be used as an indicator for larval production, and fish experience a change in shape in relation to increases in their ability to perform vital biological functions needed for survival during their early life stage. The RNA/DNA ratio is a sensitive indicator of growth rates, which can be used to evaluate growth potential and nutritional condition, as well as to determine critical periods in the larval stage. Specifically, studies on the development of the digestive tract and digestive capability of the organism can be used as an indicator of nutritional status at an early life stage, thereby providing information useful either for improving feeding protocols in larviculture, suggesting more suitable food items, or designing feasible larval rearing procedures. Through a review of previous studies, this article summarizes infor-mation on allometric growth and ontogenetic changes in nucleic acids and digestive enzymes during the early life stage of fish species. It is hoped that this review might revive interest in conducting investigations of the early life stage of fish species, and accordingly we provide some basic information meant for future studies