[Energy balance in repeated under- and overnutrition in model studies in sows]

[Thermogenesis in overfeeding with administration of olive oil and fish oil in a swine model study]

A trial on total metabolism was conducted in eight nonpregnant, nonlactating sows over eight periods, each of 16 days duration, to measure potential fatty acid induced thermogenesis. During the first and last experimental periods, the animals received a basal ration which just covered the energy maintenance requirement. In the second to seventh periods supplements of olive oil, fish oil, or puffed wheat starch as reference nutrient were added to the diet in random sequence at two levels up to 50% above the maintenance requirement. All rations were calculated with reference to the sows' initial weight and remained quantitatively unchanged throughout the experiment. The animals were fed twice daily. During each metabolism period a complete energy balance was assessed for all sows by means of collection technique (feed, feces, urine), and 48-h measurements of the gas exchange in a respiration chamber. The sows' body mass increased linearly during the course of the experiment by 5.8 kg per period. The three supplement types had no influence on the animals' final body weight, wich averaged 205.5 kg with the starch supplement, 204.8 kg with olive oil, and 205.8 kg with fish oil. Energy digestibility (DE/GE) was 100% for all three supplements, and metabolizability of energy (ME/GE) one percentage point less. Carbon and energy depositions showed a pronounced linear relationship to the level of supplementation and were also influenced by the type of supplement. Heat production was 20.9 MJ/d after feeding the basal ration alone and, taking the average of the two supplementation levels, 21.6 MJ for the starch supplement, 21.0 MJ for olive oil, and 20.6 MJ for fish oil.(ABSTRACT TRUNCATED AT 250 WORDS)

[Thermogenesis and energy utilization of olive oil and fish oil 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 basal diet (20 g DM/kg W0.75) was mainly based on barley and soybean meal, and matched 60% of the ME requirements with all the other nutrients meeting maintenance requirements. The isoenergetic supplements amounted to 176 kJ gross energy per kg W0.75 and day. During each experimental period a complete energy balance was recorded for each animal using indirect calorimetry technique (RQ-method) as well as the carbon-nitrogen-balance technique. The treatments did not influence the digestibility of the rations. Digestibility of energy and of carbon averaged 83.4% and 83.3%, respectively. All three supplements were nearly completely digested as calculated by the difference method. Fish oil increased urine energy and decreased CH4 production, the shifts, however, were in absolute terms very small. The mean O2 consumption was 1,002 l/d showing no significant treatment effects. CO2 production was lowered with olive oil by 10%, and with fish oil by 13% compared to the starch diet. The daily heat production was 20.95, 20.72, and 20.04 MJ when starch, olive oil or fish oil was given. Corrected for equal energy retention 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 differences corresponded to a relation of starch:olive oil:fish oil = 1:0.95:0.86. The relation between starch and olive oil reflected exactly the theoretical expectation, calculated from the ATP regeneration by oxidation of both nutrients. When fish oil was added, the daily heat production was lower than theoretically calculated, which might be interpreted as an effect on the metabolic rate in general rather than especially on the efficiency of ATP formation from fish oil oxidation. In any case, there was no hint of a facultative thermogenesis induced by the oils.

[The effect of palmitic, oleic and linoleic acids on thermogenesis in the model experiment in sows]

An animal model experiment was conducted with nine adult sows to study the effects of long-chain fatty acids on thermogenesis when different fatty acids were replaced for 30% of the energy of a basal diet based on cereals and soybean meal. The acids were fed as commercial products containing as main constituent either palmitic acid, oleic acid, or linoleic acid, according to a latin square design in experimental periods 2 to 4. In periods 1 and 5 the sows were submitted to basal diet alone. Digestibility of palmitic acid was only 36%, whereas the unsaturated fatty acids were highly absorbed (90%). Interaction effects of the undigested proportion of the long-chain fatty acids with the basal diet in hindgut fermentation could be ruled out since a supplementary experiment on three sows showed no influence of infusion of oleic or linoleic acid into the caecum on the energy utilization of the basal diet. There was no significant differences in thermogenesis among the fatty acids. Heat production in the treatment periods averaged -1.2% as compared to the basal diet periods. This result was in accordance with the value -1.0% calculated theoretically for the reduction in heat production in the treatment periods. Thus, the data did not indicate any stimulating effect of long-chain fatty acids on heat production, and utilization of energy of fatty acids occurred within the obligatory thermogenesis.