OLESTRA DOSE-RESPONSE ON FAT-SOLUBLE AND WATER-SOLUBLE NUTRIENTS IN THE PIG

Groups of weanling pigs were fed a purified diet containing graded con centrations of olestra ranging from 1.1 to 7.7% (wt/wt) and the NRC's requirements for micronutrients for 12 wk. Each group consisted of 12 pigs, with the exception of the control group, which had 20, with equa l numbers of females and castrated males. The purpose of the study was to determine the dose-response effects of olestra on fat-soluble vita mins and selected water-soluble micronutrients. At wk 0, 4, 8 and 12, hematology, clinical chemistry and blood concentrations of vitamins A, E, K and B-12, and 25-hydroxyvitamin D, 1,25-dihydroxyvitamin D, fola te, calcium, iron, zinc and adipose concentration of vitamin E were me asured. Cumulative weight gain and feed efficiency were determined wee kly. Prothrombin time was measured weekly for the control group and th e groups fed 5.5 or 7.7% olestra, and monthly for other groups. Liver concentrations of vitamins A, E, and B-12 and iron and bone concentrat ions of calcium, phosphorus, zinc and ash were measured for 12 pigs ki lled at wk 0 and for all animals at wk 12. By wk 12, the pigs were eat ing from 20 to 155 g/d of olestra. Olestra did not affect the pigs' gr owth or feed efficiency, indicating that the digestion and absorption of macronutrients were unaffected. Olestra reduced tissue concentratio ns of vitamin A, vitamin E and 25-hydroxyergocalciferol in a dose-resp onsive manner but did not affect prothrombin time. Olestra had no effe ct on the status of folate, vitamin B-12, zinc or iron. Statistically reduced liver concentrations of vitamin B-12 and iron in groups fed 5. 5 or 7.7% olestra and a significant trend in bone ash content with ole stra intake were possibly due to the poor vitamin A and/or vitamin E s tatus of the pigs.