Relationships between hydrogenation and hydrolysis of dietary fat in the bovine rumen : a thesis presented in partial fulfilment of the requirements for the degree of Master of Agricultural Science in Animal Science

Abstract

One of the earliest detailed comparisons of the fatty acid and glyceride composition of the depot fats of ruminants and non-ruminants in relation to the diet fed may be obtained from the work of Banks and Hilditch (1931, 1932). These studies involved beef tallows and sow depot fats respectively, and were part of an investigation of the fatty characteristics of market meat. It had been known for some time that very soft body fats, which have always been undesirable from the consumer's point of view, were produced when pigs were fed diets containing high levels of unsaturated fats. Banks and Hilditch (1932) found that the characteristic fatty acids of animal and vegetable fats when fed appeared in sow depot fats. In this case, the sow was fed a diet containing 7% of fish meal, which contains some 20% of unsaturated C20 and C22 fatty acids together with a similar amount of linoleic acid. All these fatty acids appeared in significant amounts in the depot fats of the sow. In contrast, Banks and Hilditch (1931) found that beef tallows contained much less oleic acid and linoleic acid than was present in the diet. Other studies carried out by Thomas, Culbertson and Beard (1934) and by Edwards and Holley (1939) also showed that the type of fatty diet fed to cattle had little effect on the characteristics of the depot fats. Edwards and Holley (1939) note in their paper however, that a liberal allowance of oil in the diet will tend to soften the depot fat of cattle slightly if fed for a long enough period of time.