Effects of Vitamin Nutrition on the Immune Response of Hatchery-Reared Salmonids, 1987 Annual Report.

Abstract

EXECUTIVE SUMMARYThe Abernathy Salmon Culture Technology Center (A.S.C.T.C.) and the Department of Microbiology at Oregon State University, with funding from the Bonneville Power Administration, are presently conducting a study on the effects of vitamin nutrition on immunity and disease resistance in chinook salmon (Oncorhynchus tshawptscha). The long range goal of this project is to define the dietary levels of pyridoxine, folic acid, pantothenic acid, riboflavin, ascorbic acid and vitamin E required to assure maximum resistance to disease.In the third year of this study we have completed the vitamins riboflavin and pantothenic acid. We first approximated dietary concentrations of these vitamins s that would exert the greatest e ffects on the immune response of salmon. Appropriate vitamin concentration ranges for both vitamins were then tested in a practical (Abernathy diet) and a semi-purified (modified Oregon Test Diet) ration to determine what concentration of vitamin would be required to gain some beneficial effects in a practical feed, and to determine the absolute requirements for immunological sufficiency.Results indicate that there are marginal differences in the immunological parameters tested withrespect to the Vitamin concentrations incorporated into the diets. However, the in vitro and in vivo studies --e -indicate that the Abernathy diet can provide greater enhancement of the development of immune responsiveness over that seen with the semi-purifies diet. This may be related to the increased growth rate or feed conversion of fish maintained on the Abernathy diet. 1The vitamins chosenfor study were pyridoxine, pantothenic acid, riboflavin, folic acid, Vitamin E, and ascorbic acid. A practical fish feed formulation and a semi-purified test diet are to be compounded to contain incremental amounts of the test vitamins. Each vitamin will be studied singly while dietary levels of all other vitamins are held constant, using the supplementation rates specified C in the vitamin packages for each diet.The test diets are fed for up to 24 : weeks to duplicate lots of spring chinook juveniles held indoors in circular tanks supplied with well water.During rearing, each lot of fish is weighed biweekly and dead fish are removed and recorded daily to: (1) determine growth rates, (2) calculate food conversion efficiencies, (3) provide population weights on which to base feeding rates, and (4) determine survival rates. Samples of test feeds are analyzed regularly to verify vitamin dietary concentrations, and fish organs will be analyzed for vitamin levels at the termination of each study.