Herring meals prepared with and without the addition of 0.025 % of 1,Zdihydro-6-ethoxy-2,2,4-trimethylquinoline (EQ) were stored for ten months at -20 "C and 21 "C. Storage changes in the biologically determined energy and protein values of the meals were monitored and related to changes in the chemical characteristics of the meal. Antioxidant treatment stabilised the meal lipid against oxidative changes resulting in loss of solubility, decline in iodine value and formation of peroxides and malonaldehyde. The effect of storage temperature on the course of oxidation depended upon whether the meal was treated with EQ. Lipid in meals without EQ tended to show greater change early in the storage period at -20 "C. Antioxidant-treated meals showed protection of the protein against changes leading to reduced digestibility and lysine availability. Either antioxidant treatment or storage at -20 "C protected the biological availability of the energy-supplying nutrients present in the meal,