The effect of L-ascorbic acid on the growth of salmon and trout
Date
1973
Authors
Coombs, Robert William
Journal Title
Journal ISSN
Volume Title
Publisher
Abstract
As part of a continuing study into the growth and nutrition of salmonid fishes, a new fish diet was formulated and shown to supply their nutrient needs at a cost below that of a commercial ration. During the early stages of investigation, l-ascorbic acid (vitamin C) deficiency-like symptoms appeared among rainbow trout receiving the new diet. Stimulated by this finding, a series of experiments were conducted to elucidate the nutritional and microbial responses of four salmonid species to two l-ascorbic acid supplemented rations.
There was a marked nutritional response of the four species to l-ascorbic acid supplementation of their diet. For fish receiving 60 to 400 mg of l-ascorbic acid per kilo of diet, there was an increased survival, growth rate, fat storage, and tolerance to nitrogen embolism. The levels of l-ascorbic acid in the blood, liver, kidney and gill tissues were shown to reflect in a linear manner, the supplementation levels in the diet.
The microbial response of the fish to l-ascorbic acid supplementation of their diet was also marked. The counts of intestinal mesophilic bacteria were found to be significantly lower for fish receiving diets supplemented with l-ascorbic acid.
As an initial aspect of a study into salmonid fish egg development and maternal nutrition, the 1-ascorbic acid level in individual rainbow trout eggs was evaluated. The l-ascorbic acid isolated from these eggs was partially characterized by the spectral and paper chromatographic analysis of an osazone derivative.
The absence of information concerning several important aspects of the function of 1-ascorbic acid in fish nutrition is noted and discussed.
The need for standardized rearing conditions in fish nutrition experiments provided the stimulus for the design of a new experimental self-cleaning fish tank that afforded a maximum weight of fish per unit volume of water by maintaining adequate dissolved oxygen levels with a venturi-type water admission device.
As part of a study being conducted by this laboratory into the rearing of axenic salmonid fish, an axenic fish rearing chamber was also designed and tested.