COMPARATIVE INVESTIGATION ON THE UTILIZATION OF GLYCEROL, FREE FATTY-ACIDS, FREE FATTY-ACIDS IN COMBINATION WITH GLYCEROL AND VEGETABLE OILIN FATTENING OF PIGS

The utilization of supplemented plant oil or free fatty acids in compa rison to free fatty acids and glycerol was investigated in a feeding e xperiment. The free fatty acids originated from soyabean oil and rape- seed oil (1 : 1). Five groups of six barrows (27 kg average body weigh t at the beginning) received the experimental diets for 14 weeks. The five dietary treatments were as follows: Control group 1, barley-soya bean meal (basal diet); control group 2, basal diet+10% glycerol; grou p 3, basal diet +3.2% fatty acids; group 4, basal diet +2.4% fatty aci ds +0.8% glycerol; group 5, basal diet +3.2% vegetable oil. The metabo lizable energy (ME) of diets was increased in groups 3 and 5 by 7.1% a nd in the group 4 by 5.8% compared with control group 1. Glycerol grou p 2 showed the highest feed intake. In groups 1-5 the daily live weigh t gain was 742 g, 787 g, 784 g, 739 g and 716 g, respectively. The fee d conversion ratio showed no significant differences between the group s. The back fat thickness was highest in groups 3 and 5, due to the in creased ME in these diets. The content of polyenic fatty acids in the back fat was 9.5, 8.0, 15.5, 15.3 and 16.8% in groups 1-5, respectivel y. The incorporation of polyenic acids was higher when vegetable oil w as in the diet in comparison to free fatty acids. The contents of palm itic acid (C16:0) and stearic acid (C18:0) were highest in both contro l groups without far addition.