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A new canola strain capable of producing >30% [gamma]-linolenic acid [GLA, 18:3(n-6)] in the seed oil has been developed in our laboratories. This study compares the intestinal absorption and lymphatic transport of this newly developed high GLA content canola oil (HGCO) with traditional GLA-rich borage oil (BO) using a lymph fistula rat model. To assess the extent that 1 mL of GLA in the supplemented oil was absorbed and transported, the fatty acid compositions of triglycerides in mesenteric lymph were compared over a 24-h collection period. The digestion, uptake and lymphatic transport of HGCO and the normal physiologic changes associated with fat absorption (e.g., lymph flow and an increase in lymphatic endogenous lipids outputs, triglycerides, cholesterol and phospholipids) were similar in the HGCO-and the BO-fed rats. The original differences in [gamma]-linolenic acid content in HGCO and BO were preserved in the fatty acid composition of the rats' lymph lipid. We conclude that the HGCO derived from the genetically modified canola plant is absorbed and transported into lymph similarly to BO. J. Nutr. 132: 218-221, 2002. KEY WORDS: * [gamma]-linolenic acid * intestinal lipid absorption * genetically modified canola oil * lymphatic lipids * rats

High fat diets increase body fat stores. The following experiment was undertaken to determine whether the type of dietary fat could influence fat storage and whether voluntary exercise could prevent diet-induced obesity in mice fed high fat diets. Sixty-nine 6-wk-old female mice were fed one of three diets: low fat (11.5% of energy from fat), beef fat (40.8% of energy from fat) or canola oil (40.8% of energy from fat). In each diet group, 13 mice had free access to activity wheels in their cages (exercising), and the remaining 10 mice were housed in standard mouse cages (nonexercising). Body weight and body composition were measured before and after 8 wk of treatment. The nonexercising mice fed beef fat weighed more and had significantly more body fat (23.2 [+ or -] 2.5 g/100 g body wt) than mice fed the low fat or canola oil diet (13.9 [+ or -] 1.7 and 16.8 [+ or -] 1.9 g/100 g body wt, respectively). Voluntary exercise did not affect lean body mass but did result in significantly lower body fat in all diet groups (beef, 12.6 [+ or -] 0.9; low fat, 7.4 [+ or -] 0.6; canola oil, 9.6 [+ or -] 1.4 g/100 g body wt). The amount of body fat of mice fed the monounsaturated canola oil was significantly less than that of mice fed the beef fat diet, suggesting that the type of fat as well as the amount of fat influences body fat stores. Furthermore, voluntary exercise decreased body fat in all mice and prevented diet-induced obesity in mice fed diets high in fat. KEY WORDS: dietary fat; obesity; exercise; mice

Previous research showed that dietary fish oil was potently antiarrhythmic in rats but olive oil was not. This study was designed to test the hypothesis that canola oil, another major dietary source of oleic acid additionally containing the (n-3) polyunsaturated fatty acid [Alpha]-linolenic acid [18:3(n-3)], can reduce vulnerability to cardiac arrhythmia in rats. Rats were randomly assigned to one of four experimental diet groups for 12 wk. The fat source in the diets was 12% olive (63% oleic acid), canola (55% oleic, 8% [Alpha]-linolenic acid), soybean [50% linoleic 18:2(n-6), 7% [Alpha]-linolenic acid] or sunflower seed oil (64% linoleic acid). Arrhythmias were induced by coronary artery occlusion and reperfusion. Incidence of ventricular fibrillation, mortality and arrhythmia score during reperfusion were significantly lower in rats fed the diet containing canola oil than in those fed the olive oil diet. No difference in the severity of arrhythmias was seen in groups fed diets containing soybean or sunflower seed oils. Analysis of myocardial phospholipid fatty acids showed that consumption of canola oil decreased the ratio of (n-6)/(n-3) polyunsaturated fatty acids relative to the other diets, as does dietary fish oil. These results suggest that regular substitution of canola oil for other dietary lipid sources may assist in reducing the likelihood of a transient ischemic event leading to life-threatening cardiac arrhythmias, but the effectiveness of [Alpha]-linolenic acid is reduced by high levels of linoleic acid. INDEXING KEY WORDS: reperfusion; (n-3) fatty acids; canola; arrhythmia; [Alpha]-linolenic acid; rats

Studies were carried out with 12 pigs (Yorkshire x Landrace) to determine the effect of dietary fat content on amino acid digestibility. The pigs were weaned at 21 d of age and fitted with a simple T-cannula at the distal ileum at 27 or 28 d of age. After a 7-d recuperation period, the pigs were fed one of four isonitrogenous cornstarch-based soybean meal diets (22.5% CP) containing 3.2, 6.2, 9.2, or 12.2% canola oil according to a balanced two-period change-over design. The pigs were fed four times daily, equal amounts, at 6-h intervals. The diets were supplied at a rate of 5% of the average body weight that was determined at the initiation of the first (11.0 kg) and second (12.5 kg) experimental period. Each experimental period consisted of 10 d. Feces were collected for 48 h on d 6 and 7 and ileal digesta for 24 h during d 8, 9, and 10. Chromic oxide was used as digestibility marker. The apparent ileal digestibilities of most of the amino acids increased linearly (P [is less than] .05) with increasing dietary fat levels. There were differences (P [is less than] .05) in the ileal digestibilities of most of the amino acids between the diets containing 3.2 and 12.2% canola oil. Conversely, the dietary level of inclusion of canola oil did not affect (P [is less than] .05) the fecal amino acid digestibilities. The protein-sparing effect of additional canola oil inclusion results, in part, from an increase in ileal amino acid digestibility.

Our group has compared plasma lipids in randomised crossover trials in which approximately half the fat intake of subjects was changed from palmolein to each of three predominantly monounsaturated oils [...]