传染性疾病是引起密集养鱼产量下降的主要原因。在鱼类生存的水环境中普遍存在大量的潜在病原。当鱼类、病原体和生存环境间的平衡关系紊乱时,就会发生鱼病。人们常认为,水质低劣,养殖密度过高,养殖管理差或水体污染所造成的环境影响都可能是鱼类的致病因子。可以认为投饵量及营养素的平衡亦是引起鱼病的原因之一,但有关的研究论文尚不多见。Durve 与 Lovell(1982)认为用含维生素 C 较高的饵料喂养受到 Edwardsiella tar-da 实验性感染的斑点叉尾(鱼回)幼鱼,可降低其死亡率。Malikova 等(1961)曾两次提出当饵料中维生素 A 的含量达每公斤300,000国际 Infectious diseases are the main cause of the decline in intensive fish production. A large number of potential pathogens are prevalent in the aquatic environment in which fish live. Fish disease occurs when the balance between fish, pathogens and living conditions is disturbed. People often think that the environmental impact caused by poor water quality, high breeding density, poor culture management or water pollution may all be the causative agents of fish. It can be considered that the balance of feeding amount and nutrients is also one of the causes of fish diseases, but the relevant research papers are rare. Durve and Lovell (1982) suggested that feeding turtles (fish) catfish that were experimentally infected with Edwardsiella tar-da with a diet containing higher levels of vitamin C reduced their mortality. Malikova et al. (1961) proposed twice that when the content of vitamin A in feed is up to 300,000 kg / kg