Holley L L, Heidman M K, Chambers R M, Sanderson S L
Edge Engineering and Science, 16360 Park Ten Place, Suite 300, Houston, TX 77084, U.S.A.
J Fish Biol. 2015 May;86(5):1457-70. doi: 10.1111/jfb.12656. Epub 2015 Mar 23.
This study developed and applied an approach to calculate the proportion of fish gut content composed of mucus secreted by the oropharyngeal cavity and gut. The amount of nitrogen in the contents of the foregut (oesophagus and gizzard) and the epibranchial organs of suspension-feeding American gizzard shad Dorosoma cepedianum was significantly higher than the nitrogen in the homogeneous food source. Using data collected from suspension-feeding experiments and the nitrogen content of D. cepedianum mucus, a series of equations illustrated that mucus constituted c. 10% of D. cepedianum foregut content and 12% of epibranchial organ content by dry mass. Future quantification of fish feeding selectivity and absorption efficiency can use this approach to take into account the contribution of fish mucus to the nutrients in the gut contents. This study supports the conclusion that suspension-feeding D. cepedianum in a heterogeneous environment selectively ingest nutrient-rich particles, even when gut nutrient content is adjusted to take into account the contribution of mucus.
本研究开发并应用了一种方法来计算鱼肠道内容物中由口咽腔和肠道分泌的黏液所占的比例。以悬浮取食的美国遮目鱼（Dorosoma cepedianum）为例，其前肠（食管和砂囊）内容物以及鳃上器官中的氮含量显著高于均质食物源中的氮含量。利用悬浮取食实验收集的数据以及遮目鱼黏液的氮含量，一系列方程式表明，按干质量计算，黏液约占遮目鱼前肠内容物的10%以及鳃上器官内容物的12%。未来在对鱼类摄食选择性和吸收效率进行量化时，可采用此方法来考量鱼黏液对肠道内容物中营养物质的贡献。本研究支持以下结论：即使在调整肠道营养成分以考虑黏液贡献的情况下，处于异质环境中的悬浮取食遮目鱼仍会选择性摄取营养丰富的颗粒。
