A Study of the Methodology for Assaying Unidentified Growth Factor in Fish Meal and Fish Solubles

Abstract

Four experiments were conducted using a crystalline amino acid diet to establish an improved bioassay for evaluating the unidentified growth factor(s) (U.G.F.) in fishery products. To maintain constant levels of nutrients, dietary adjustments were made to equalize the content of selenium (Se), fish oil and of each amino acid based on the chemical analyses of the test materials. In this manner, the existence of the U.G.F. was demonstrated in the presence of an intact protein (5% gelatin), and constant total levels of proline (0.82%), Se (0.5 p.p.m.) and fish oil (1%). The U.G.F. response from fishery products appears to be independent of the intestinal flora as indicated by a gnotobiotic experiment.