This study assessed the effects of diets supplemented with different types of chitin hydrolysate on larval growth of the Japanese eel Anguilla japonica. Larvae were reared for 26 days on artificial diets containing 2% of purified monomeric N-acetylglucosamine (NAG1), a mixture of mono-, di- and trimers (NAG3), a mixture of mono-, di-, tri-, tetra-, penta- and hexamers (NAG6), or a control diet. The larvae fed NAG3 and NAG6 grew significantly more rapidly than the control larvae (p < 0.05). However, the survival rate of the NAG6-fed larvae was low (8%) for unknown reasons, whereas the survival rates of the NAG1 and NAG3-fed larvae were similar to that of control larvae, about 46% (p > 0.9). These results indicate that NAG3 is the most effective supplement for eel larvae. A dose–response analysis showed that the optimal level of NAG3 in the diet was around 1%. Although the biological activity of chitin hydrolysates in eel larvae remains unclear, part of these hydrolysates are likely utilized by eel larvae as components of glycosaminoglycan, a major constituent of their bodies. Alternatively, the hydrolysates may act as a bioactive substance, influencing fish health, or in the effective utilization of energy in eel larvae, enhancing their growth.

中文翻译：

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日粮中添加几丁质水解物治疗鳗鲡鱼

本研究评估了添加不同类型几丁质水解物的饮食对日本鳗鲡幼虫生长的影响。幼虫在含有 2% 纯化单体 N-乙酰氨基葡萄糖 (NAG1)、单聚体、二聚体和三聚体 (NAG3) 的混合物、单聚体、二聚体、三聚体、四聚体的混合物的人工饲料中饲养 26 天。 、五聚体和六聚体 (NAG6) 或对照饮食。喂食 NAG3 和 NAG6 的幼虫比对照幼虫生长得更快（p < 0.05）。然而，由于未知原因，NAG6 喂养的幼虫的存活率较低 (8%)，而 NAG1 和 NAG3 喂养的幼虫的存活率与对照幼虫的存活率相似，约为 46% (p > 0.9)。这些结果表明 NAG3 是鳗鱼幼虫最有效的补充剂。剂量反应分析表明，饮食中 NAG3 的最佳水平约为 1%。虽然鳗鱼幼虫中几丁质水解物的生物活性尚不清楚，但这些水解物的一部分很可能被鳗鱼幼虫用作糖胺聚糖的成分，糖胺聚糖是它们身体的主要成分。或者，水解物可作为生物活性物质，影响鱼类健康，或有效利用鳗鱼幼虫的能量，促进其生长。