FISH MEAL.

Auckland Star, Volume LIX, Issue 120, 23 May 1928, Page 19

FISH MEAL.

HIGHLY-CONCENTRATED

STOCK FOOD.

A POSSIBLE DOMINION INDUSTRY.

(By "SUNDOWNER.")

In Great Britain there is conducted

a very extensive business which uses to the very last particle the refuse and by-products of the enormous fishing industry. This unsavoury material, by thousands of tons, is put through various processes in which it is ground, dried, has its oil content extracted from it, and is finally returned to the market in various forms, princi pally as fish meal and fish oil. An important Stock Food. Though we hear comparatively little of it in this country fish meal has now claimed a most important position on the British and Continental markets as a concentrated stock food. So great is the demand for it, especially from the Continent, that, in spite of the enormous supply of raw material, practically all of which is now being converted int-o meal and oil, the demand far exceeds the supply. The fish meal produced from whole fish or even fish refuse is almost white in colour, has quite a pleasant fresh smell, and contains 70.82 per cent of raw protein, 13.10 per cent phosphate of lime, 14.92 per cent of other mineral substances and minute quantities of fat, common salt and water.

The digestibility of raw protein—the most valuable part of any animal food —is between 90 and 95 per cent, while the phosphate of lime is an extremely valuable bone-forming food which is supplemented by the other mineral content of the meal, most of which can be profitably used by the animal system. It will, therefore, be seen that, used as a concentrate with other food, such as bulky hay or ensilage, this fish meal is an extremely rich concentrate, practically every bit of which can be absorbed by the animal's system. It may seem rather an extraordinary thing to feed a meal of this sort to herbivorous animals, nevertheless, it is being done on an ewer-increasing scale, and perhaps, really there is little difference between feeding fish meal to cattle and the now commonly adopted practice of giving poultry meat meal, bone meal, etc. Extraction of Fish Oil. The only part of the fish that appears to be indigestible or harmful to cattle if taken in $*cepa it| the oil, asd in

preparation of the meat it undergoes An elaborate process, during which this is extracted until the oil residue does not amount to more than one or at most two p<;r cmt. The oil is extracted from the finely ground fish by passing through it a quantity of oil solvent—a chemical called trichlor&thylen, which resembles benzine, but is non-explosive. This solution is then pumped and drained off, after which all taint is removed from the meal by passing steam through it. Ihe oil and its solvent are separated, the former finding a ready market for the manufacture of soap, etc., while the solvent is used again and again for the same .purpose. So complete is the •machinery used for the manufacture of this fish meal that even the objectionable gases extracted from the fi«sh refuse during manufacture are collected and led by pipes to the boiler furnace, where, being combustible, they help to keep steam up. Every kind of fish is used. From the enormous whales, seals, sharks, rays and similar monsters of the deep down to all the small fish brought up with the net when fishing, and which are termed "small fry," as well as other marine animals such as star fish, crabs, snails, worms, etc.—one and all find their way into this meal, which is bidding fair to oust linseed meal from the popular place which it has hitherto held as a stockfood concentrate. Concentrates For New Zealand Stock. There is coming a time in New Zealand when we, in common with tha producers in the Old World, will find the necessity of feeding more and more concentrates to our stock in order to produce the early maturity that is demanded in beef, pork and mutton, and also the intense stocking of areas where butter and similar products are produced. When that time comes, and it may be much closer than most of us suppose, we may find in our fish and fish refuse the raw material for our most valuable concentrate.

One point in connection wth the manufacture of fish meal and fish oil which is of considerable importance to the manufacturer in these days when labour constitutes such a big proportion of the overhead costs cf manufacture, is that with the exception of the manual labour entailed in feeding the fish into the first crushing mill, and sewing the mouths of the bags of finished product, the whole of the process is mechanical. Conveyors take the product from one process to the other, where it is sterilised and evaporated at temperatures controlled by thermostats, while grinding, oil extraction, and so forth, are performed <by machines which are controlled by a clock.