GLYCEROL AS A FEED COMPONENT IN DIETS OF FATTENING PIGS

The production of motor fuel from rapseed oil forms large amounts of g lycerol as a waste product (about 100 g per kg oil). The aim of this e xperiment was to test glycerol as a component in diets of fattening pi gs. In two experiments received 48 pigs (Pietrain x F1, Landrace x Ger man breed) up to 30% glycerol in barley-soya bean oil meal diets. Six pigs per group with an initial weight of 32 kg (experiment 1) and 31,2 kg (experiment 2) in average received the diets semi ad libitum durin g the whole fattening periods. Barley was replaced by glycerol, that t he content of glycerol in diets amounted 5 and 10% (1th exp.) and 5; 1 0; 20 and 30% in the 2nd exp. respectively. The feed intake was in ord er of groups up to slaughtering in exp. 1: 1.98; 2.17 and 2.23 kg DM/a nimal and day and in exp. 2 over 71 days: 2.26; 2.44; 2.54; 2.32 and 2 .37 kg DM/ animal and day. The sweetish taste and the better feed stru cture of diets with glycerol supplementation is the reason for the hig her feed intake in the groups with a glycerol supplement. The daily li ve weight gain was in the same order 631; 719; 754; 731; 770; 819; 704 and 598 g/animal resp.. The feed conversion ratio was only in the gro up with 30% glycerol significant different from all other groups (3.96 against 2.95-3.30 kg DM/kg live weight gain). 30 min. after feeding t he glycerol concentration in blood rose evident with higher glycerol c ontent in diets. It was also found a higher glycerol content in the ur ine in dependence on the glycerol concentration in the blood. Glycerol in diets changed not the carcass yield and the meat quality. Patholog ical changes of liver and kidney of animals were not found after glyce rol feeding. Amounts of glycerol up to 10% in the diet are recommended .