Feeding of partially hydrogenated fish oils to rats in comparison with partially hydrogenated soybean oil and refined rapeseed oil: a combined chronic oral toxicity and carcinogenicity study with in utero phase.

Partially hydrogenated fish oils (PHFO) have been widely used in human food products for many years, particularly in Europe, North and South America and in South Africa. Animal studies, mainly with rapeseed oil, suggested that erucic acid might be responsible for morphological changes in the myocardium. It was suggested that other members of the docosenoic (22:1) family of fatty acids might produce similar effects to those ascribed to erucic acid. Certain PHFO can contain relatively high levels of these other isomers. Thus it was decided to evaluate PHFO of differing 22:1 levels in comparison with partially hydrogenated soybean oil (PHSBO) and refined rapeseed oil (LEAR) in a rat life span study, preceded by a breeding period in which the experimental lipids were fed to male and female parents. Two commercially produced PHFO were selected to represent the lower (PHFO-L) and upper (PHFO-U) range of 22:1 contents, 4.3 and 13.8%, respectively. A third test oil was prepared from a 50:50 blend of these (PHFO-M) to provide and intermediary 22:1 level. The control PHSBO and LEAR contained 0 and 1.0% 22:1, respectively. These experimental oils were included in semi-purified diets at 8 and 16%, respectively, in the breeding and life span periods of the study, together with 4% of oil mixtures providing essential fatty acids (EFA). Specific pathogen free (SPF). Wistar weanling rats, 200 of each sex, provided the subjects for the breeding period. Sufficient numbers of offspring were obtained in suitable condition from each treatment group to allow selection of a total of 555 weanlings for allocation to the five dietary treatments of the life span period of the study. For the life span period of the study, which was terminated after 107 to 110 weeks of treatment, 50 subjects were allocated to each of the PHSBO, PHFO-L and PHFO-U dietary groups, and 50 males to each of the LEAR and PHFO-M groups. The remaining subjects were allocated to sub-groups for sacrifice four days or 26 weeks after introduction of the life span period diets. All life span group subjects were weighed and had their food intakes recorded, and were subjected to clinical examination, routinely. At designated stages, ophthalmoscopic examination of all subjects was carried out, and samples of blood and urine were obtained from sub-groups for laboratory analysis. All decedent and terminated life span group subjects were subjected to post mortem examination, with weighing of 16 organs.(ABSTRACT TRUNCATED AT 400 WORDS)

Two methods for determining erucic acid in edible fats and oils: results from a collaborative study on a rapid, open-tubular (capillary) GLC method and comparison with an isolation TLC procedure.

The results of an international collaborative study for the determination of 5% erucic acid in four samples of edible fats and oils with differing levels of 22:1 isomers other than erucic acid, based on the use of wall-coated (SILAR-5CP) open-tubular gas-liquid chromatography, are examined. The same samples had been analyzed in a separate collaborative study by an alternative and more complex method based on argentation thin-layer chromatography. Both methods rejected about the same proportion of participating laboratories and a few individual results from otherwise acceptable laboratories. The means and repeatabilities of the two methods were similar, but the gas-liquid chromatographic method showed better reproducibility.

Comparison of lipid status in the hearts of piglets and rats on short term feeding of marine oils and rapeseed oils.

A series of 4 experiments with piglets and one experiment with rats has been conducted to establish the cardiac lipid status of weanling (3 weeks old) male animals fed fats with different contents of docosenoic fatty acids. Experimental fats were rapeseed oil (RSO) (48.0% 22:1), refined fish oil (RFO) (14.6% 22:1), partially hydrogenated fish oil (PHFO) (14.3% 22:1) and lard (0% 22:1) combined with sunflower seed oil (SFO) in different proportions in diets with 21% total fat. Lipidosis could not be detected in piglets as increased heart weights, by chemical assay for myocardial contents of triglycerides, or by accumulation of docosenoic fatty acids or nonesterified fatty acids (NEFA). In rats, diets with RSO at a level of 16% increased myocardial triglyceride and docosenoic fatty acid contents about 7 times while the effect on cardiac NEFA was inconsistent. Histological examinations of the hearts revealed stainable intracellular fat droplets in some piglets fed 16% RSO for 8 to 13 days, but not after 2, 4 and 6 and 16, 19 and 22 days of feeding. After 10 days of feeding, mild to moderate histological lipidosis was found in piglets fed diets containing 2% or more of 22:1 fatty acids, with no significant difference between RSO, RFO and PHFO in this respect. The same diets in rats gave about 5 times more histological lipidosis than in piglets. This is attributed to a difference in species response, the rat reacting in a more pronounced manner than the piglet. The cardiac lipidosis no-effect level in piglets corresponded to a daily intake of docosenoic fatty acids of 0.4 g per kg body weight. Mild lipidosis was also found in a few animals on docosenoic acid-free diets.

Erucic acid in edible fats and oils: a collaborative study on determination by open-tubular (capillary) gas-liquid chromatography.

An open-tubular (capillary) column gas-liquid chromatographic method for the determination of the specific isomer of docosenoic acid known as erucic acid (cis-docos-13-enoic) in the presence of other docosenoic acid isomers present in partially hydrogenated marine oils has been evaluated collaboratively. With wall-coated columns and the liquid phase SILAR-5CP, nine laboratories successfully analysed mixtures of partially hydrogenated marine oils, corn oil and rapeseed oil with a nominal content of 10% erucic acid, compatible with the regulations of the European Economic Community.