EFFECT OF DIETARY CANOLA OIL AND ITS DEGREE OF OXIDATION ON EXOCRINE PANCREATIC SECRETIONS IN GROWING PIGS

Four barrows, average initial weight 35 kg, were fitted with permanent pancreatic re-entrant cannulas and used to determine the effect of le vel and quality of dietary fat on exocrine pancreatic secretions. The pigs were fed four corn starch-based diets that contained 15 % crude p rotein from isolated soy protein. Diet 1 contained no canola oil (C-0) ; diet 2, 15 % canola oil (C-15); diet 3, 15 % canola oil that was hea ted under vacuum at 180 degrees C for 12 h (C-15/12); diet 4, 15 % can ola oil that was heated under vacuum at 180 degrees C for 24 h (C-15/2 4). Heat treatment resulted in a 4- to 5-fold increase in the content of malonaldehyde which is derived from the oxidation of fatty acids an d which is closely related to odour and rancidity in lipids. The exper iment was carried out according to a 4 x 4 Latin square design. The pi gs were fed twice daily, at 08:00 and 20:00 h, 900 g each meal. Follow ing an adaptation period of 7 d, pancreatic juice was collected contin uously for 24 h at 2-h intervals from 08:00 on d 8 until 08:00 on d 9 and from 08:00 on d 10 until 08:00 on d 11 during each experimental pe riod. The volume of secretion of pancreatic juice peaked 6-10 h postpr andially and was similar (P > .05) during day (08:00-20:00 h) and nigh t (20:00-08:00 h). Replacement of 15 % starch by 15 % canola oil resul ted in a decrease (P < .05) in the secretion of alpha-amylase and an i ncrease (P < .05) in the secretion of lipase. The inclusion of oxidize d fat caused a further increase (P < .05) in total lipase activities. It can be concluded that the exocrine pancreas is able to adapt to var iations in the level and quality of dietary lipids.