One hundred and eighty weaner pigs were allotted to five dietary treatments comprising a control with no added oil and the control with either soybean oil or rapeseed oil (Brassica campestris cv. Span) each at 10 and 20% of the diet. Postmortem examinations were conducted on equal numbers of boars and gilts at the beginning of the experiment, as initial controls, and after 1, 4 and 16 wk on the experimental diets. When fed for 1 to 4 wk, the higher level of both oils reduced (P < 0.05) body weight gain but from 4 to 16 wk, differences were not significant for any of the diets. Consumption of the control diet exceeded (P < 0.05) that of any other diet, but pigs fed the oil diets showed improved (P < 0.01) feed efficiency. Minute focal interstitial infiltrations of mononuclear cells were present in the myocardium of some pigs in each dietary treatment and also in the initial controls. Foci of overt myocardial necrosis were not seen. Oil red 0 stained sections revealed traces of myocardial fat accumulation which occurred more frequently in pigs fed the high oil diets. In a second experiment, 24 weaner boar pigs were fed the control and the 10% Span oil diets. Two pigs from each treatment were killed on each of days 0, 4, 8, 12, 16 and 20. Total fat was extracted from the heart of each pig and methyl esters determined by gas–liquid chromatography. There was no significant (P = 0.05) difference in percent fat of dry matter between pigs fed the control and the 10% Span diet. The proportions of the major fatty acids were similar between diets. Erucic acid and linolenic acid were present in the cardiac lipid of all control pigs, but to a significantly (P < 0.01) lesser degree than for pigs fed the Span diet. The level of arachidonic acid, for both groups of pigs, declined (P < 0.05) progressively with the duration (days) of feeding.
Production of methyl esters from fried soybean oil using dimethyl carbonate with hydrobromic acid
