EFFECT OF OLIVE OIL AND FISH-OIL ON THERM OGENESIS AND UTILIZATION OFENERGY IN A MODEL STUDY WITH SOWS

An animal model experiment was conducted with nine adult sows to study the effect of olive oil and fish oil (40% polyunsaturated fatty acids ) on thermogenesis compared to wheat starch as control. The treatments were given to each animal according to a latin square design. The bas al diet (20 g DM/kg W-0.75) was mainly based on barley and soybean mea l, and matched 60% of the ME requirements with all the other nutrients meeting maintenance requirements. The isoenergetic supplements amount ed to 176 kJ gross energy per kg W-0.75 and day. During each experimen tal period a complete energy balance was recorded for each animal usin g indirect calorimetry technique (RQ-method) as well as the carbon-nit rogen-balance technique. The treatments did not influence the digestib ility of the rations. Digestibility of energy and of carbon averaged 8 3.4% and 83.3%, respectively. All three supplements were nearly comple tly digested as calculated by the difference method. Fish oil increase d urine energy and decreased CH4 production, the shifts, however, were in absolute terms very small. The mean O-2 consumption was 1002 1/d s howing no significant treatment effects. CO2 production was lowered wi th olive oil by 10%, and with fish oil by 13% compared to the starch d iet. The daily heat production was 20.95, 20.72, and 20.04 MJ when sta rch, olive oil or fish oil was given. Corrected for equal energy reten tion the difference of thermogenesis between olive oil and starch was -0.4 MJ/d, and between fish oil and starch -1.2 MJ/d. These difference s corresponded to a relation of starch:olive oil:fish oil = 1:0.95:0.8 6. The relation between starch and olive oil reflected exactly the the oretical expectation, calculated from the ATP regeneration by oxidatio n of both nutrients. When fish oil was added, the daily heat productio n was lower than theoretically calculated, which might be interpreted as an effect on the metabolic rate in general rather than especially o n the efficiency of ATP formation from fish oil oxidation. In any case , there was no hint of a facultative thermogenesis induced by the oils .