AbstractThe most promising of the various forms of ‘refuse’ still discarded to waste in British fisheries is the guts—mainly stomachs and intestines—which are thrown overboard from the trawlers. Such material is capable of giving a yield and type of meal comparable to that obtained from the usual fish offal. The guts must be preserved in order to bring them back to port, and formaldehyde at 0.4 by weight of the guts is a satisfactory preservative. Sodium nitrite seems less effective. Seaweed meal may be used but the amount required is excessive (50–100) and the final product is not very palatable. Meal made from guts preserved with formaldehyde is palatable to animals and shows no evidence of toxicity. The protein is readily hydrolysed by pepsinin vitro, and by digestive enzymes of the pigin vivo. Much of the total nitrogen of the meal cannot be accounted for as ‘true protein,’ and is probably present as partly hydrolysed protein fragments. Nevertheless, it is in a form available to the pig, as shown by nitrogen‐
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