|Document Type:||Journal Article|
|Title:||A versatile force-feeding system for experimental use with small fish|
|Author:||Anthony J. Novotny, Diptiman Chakravarti|
|Journal:||The Progressive Fish-Culturist|
Fish physiologists and nutritionists frequently study the transport rates of substances introduced into the digestive systems of fish. If the studies are to be quantitative, it is necessary to know the exact amounts introduced. The most common procedure is to enclose the substance in a gelatin capsule and force–feed it to the fish with a suitable insertion tool. This procedure has been used for studies of chemical toxicity, radiation damage, and isotope uptake. In our studies, we attempted to make quantitative measurements of the absorption rates of certain trace elements which were introduced with a normal diet to small fingerling trout and salmon. We found that gelatin capsules were not suitable for this purpose: even the smallest capsules were too large for small fingerlings (fork length 80–100 mm). In addition, all the contents might not be released, owing to incomplete breakdown of the gelatin in the upper digestive tract. These problems were averted by using a food pellet of suitable size and uniform content. To use pellets in the laboratory studies noted above, it was necessary to develop certain techniques and equipment. The following account gives details of the system devised for this purpose.