AbstractsChemistry

Nutritional requirements of trout.

by Enid Patricia. Knight




Institution: McGill University
Department: Department of Agricultural Chemistry.
Degree: PhD
Year: 1944
Keywords: Agricultural Chemistry.
Record ID: 1494584
Full text PDF: http://digitool.library.mcgill.ca/thesisfile126048.pdf


Abstract

Between 1860 and 1870 an American, Seth Green, established the first fish-rearing station somewhere in the Eastern States. From this small beginning, pisciculture has become an industry of national importance. McCay of Cornell University and Davis of the United States Bureau of Fisheries have clarified many problems pertaining to fish culture and nutrition. The food of wild trout varies with the locality, the season, and the age of the fish, but it consists mainly of the larvae of various insects such as the dragonfly or caddis fly and crayfish (l). Species’ differences play a part in food selection; for example, 15% of the stomach contents of rainbow trout consists of algae (2), while green vegetation is eaten in negligible amounts by other species of trout. Perhaps this fact may account for the difficulty which is sometimes experienced in raising rainbow trout in captivity. The food available for hatchery feeding may be divided into three classes: (a) fresh meat, such as liver, heart, et cetra; (b) dried animal products such as meat or fish meal, and dried skim-milk; (c) vegetable products such as wheat middlings and cottonseed meal. Liver was one of the first substances to be used and has continued to be one of the most successful of artificial trout foods. However, there are certain disadvantages in using liver as a trout food. For example, when scattered on the surface of the water, it imparts a milkiness due to solution of its soluble and valuable constituents. [...]