Abstract Chitin isolated from Daphnia similis and its derivate, chitosan, were prepared to evaluate the effects on the improvement of growth performance of white shrimp, Penaeus vannamei. The diets containing 0.4% chitin or 0.4% chitosan were fed to shrimp for 56 days to evaluate the growth performance of shrimp. A diet without chitin or chitosan supplementation was used as the control diet (herein known as CD). No significant difference in survival of shrimp among groups was observed. The Shrimp fed a diet containing 0.4% chitosan significantly had much higher final weight, specific growth rate and percent weight gain as well as increased its protease activity in hepatopancreas. The feed conversion ratio was also increased in the 0.4% chitosan-fed shrimp. In addition, higher gene expressions of the chitinase (CHT) 3 and chitin synthase (CHS) in hepatopancreas, and the CHT6 and CHS in cuticle were also recorded in chitosan-treated shrimp as compared to CD-treated shrimp. Chitosan derived from chitin of D. similis is considered to have great potential to promote the shrimp growth, by increasing the digestive enzyme and the gene expressions of CHTs and CHSs.

中文翻译：

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类似水蚤的几丁质及其衍生物壳聚糖促进南美白对虾的生长性能

摘要 从类似水蚤中分离出几丁质及其衍生物壳聚糖，以评价其对南美白对虾生长性能的改善作用。将含有0.4%几丁质或0.4%壳聚糖的饲料喂给虾56天，以评价虾的生长性能。没有补充几丁质或壳聚糖的饮食被用作对照饮食（在此称为 CD）。观察到各组虾的存活率没有显着差异。喂食含有 0.4% 壳聚糖的日粮的虾的最终体重、特定生长率和体重增加百分比显着更高，并增加了其在肝胰腺中的蛋白酶活性。0.4%壳聚糖喂养的虾的饲料转化率也提高了。此外，与 CD 处理的虾相比，壳聚糖处理的虾还记录了肝胰腺中几丁质酶 (CHT) 3 和几丁质合酶 (CHS) 以及表皮中 CHT6 和 CHS 的更高基因表达。来自D. similis的几丁质壳聚糖被认为具有促进虾生长的巨大潜力，通过增加消化酶和CHTs和CHSs的基因表达。