Chemical and nutritional changes in stored herring meal. Nutritional significance of oxidation of the oil.

This study was designed to investigate the nutritional significance of the interactions that may occur between oxidized fat and proteins in foods. Herring meal, because of its high content of protein and of highly unsaturated fat, was chosen as the material for study. The first two papers in the series (Lea, Parr & Carpenter, 1958, 1960) dealt mainly with factors influencing the rate of oxidation of the fat in stored herring meal, and with the interaction between fat oxidation products and the €-amino groups of the lysine units in the herring protein. This paper describes feeding tests designed to discover whether the nutritional value of the protein was influenced in other ways also during storage, and to ascertain whether the oxidized and polymerized fat of the stored meal could itself be influencing the outcome of the feeding tests by direct toxic or ‘growth-depressant’ effect. The answer to the latter question appeared to be ‘no’. During this work an unexpected growth-depressant action was encountered with meal from which the oil had been extracted by chloroform-methanol, and these findings are reported. Included also is an account of a parallel study of a particular batch of imported anchovy meal said to have shown ‘rancid fat toxicity’ for livestock.