Effect of feeding protected lipids on fatty acid synthesis in ovine tissues

6 Final Report on the Safety Assessment of Safflower Oil

Safflower Oil is a polyunsaturated edible seed oil consisting primarily of triglycerides of linoleic acid. The oil is used in cosmetics as an emollient in topical lotions and creams at concentrations normally between 0.1 and 5 percent. The pure oil produced slight to moderate comedogenicity. However, products containing up to 5 percent Safflower Oil were not comedogenic in rabbits. Results of animal tests indicated that Safflower Oil was not an eye or skin irritant or contact sensitizer. The oil increased the incidence of 12-dimethylbenz(a)anthracene in rats.

Safflower Oil has been used to treat human essential fatty acid deficiencies via oral and topical administration and is often applied to irritated and abraded skin. Products containing up to 5 percent Safflower Oil were negative for human skin irritation, sensitization, or photosensitization.

From the information presented in this report, it is concluded that Safflower Oil is safe as a cosmetic ingredient in the present practices of use.

Effects of including a ruminally protected lipid supplement in the diet on the fatty acid composition of beef muscle

Enhancing the polyunsaturated fatty acid (PUFA) and decreasing the saturated fatty acid content of beef is an important target in terms of improving the nutritional value of this food for the consumer. The present study examined the effects of feeding a ruminally protected lipid supplement (PLS) rich in PUFA on the fatty acid composition of longissimus thoracis muscle and associated subcutaneous adipose tissue. Animals were fed ad libitum on grass silage plus one of three concentrate treatments in which the lipid source was either Megalac (rich in palmitic acid; 16 : 0) or PLS (soybean, linseed and sunflower-seed oils resulting in an 18 : 2n-6:18 : 3n-3 value of 2.4:1). Treatment 1 contained 100 g Megalac/kg (Mega, control); treatment 2 (PLS1) contained 54 g Megalac/kg with 500 g PLS/d fed separately; treatment 3 (PLS2) contained no Megalac and 1000 g PLS/d fed separately. The PLS was considered as part of the overall concentrate allocation per d in maintaining an overall forage:concentrate value of 60:40 on a DM basis. Total dietary fat was formulated to be 0.07 of DM of which 0.04 was the test oil. Total intramuscular fatty acids (mg/100 g muscle) were decreased by 0.31 when feeding PLS2 compared with Mega (P<0.05). In neutral lipid, the PLS increased the proportion of 18 : 2n-6 and 18 : 3n-3 by 2.7 and 4.1 on diets PLS1 and PLS2 v. Mega, respectively. Similar responses were noted for these fatty acids in phospholipid. The amounts or proportions of 20 : 4n-6, 20 : 5n-3 or 22 : 6n-3 were not influenced by diet whereas the amounts and proportions of 22 : 4n-6 and 22 : 5n-3 in phospholipid were decreased with inclusion of the PLS. The amounts of the saturated fatty acids, 14 : 0, 16 : 0 and 18 : 0, in neutral lipid were on average 0.37 lower on treatment PLS2 compared with Mega. Feeding the PLS also decreased the proportion of 16 : 0 in neutral lipid. The amount of 18 : 1n-9 (P=0.1) and the amount and proportion of 18 : 1 trans (P<0.01) were lower on treatments PLS1 and PLS2 in neutral lipid and phospholipid. Conjugated linoleic acid (cis-9, trans-11) was not influenced by diet in the major storage fraction for this fatty acid, neutral lipid. The PUFA:saturated fatty acids value was increased markedly (x2.5) with inclusion of the PLS (P<0.001) while the Sigman-6 : n-3 value increased slightly (x1.2; P=0.015). The results suggest that the protected lipid used, which was rich in PUFA, had a high degree of protection from the hydrogenating action of rumen micro-organisms. The PLS resulted in meat with a lower content of total fat, decreased saturated fatty acids and much higher 18 : 2n-6 and 18 : 3n-3. The net result was a large shift in polyunsaturated: saturated fatty acids, 0.28 v. 0.08, on feeding PLS2 compared with Mega, respectively.

Dietary whole cottonseed depresses lipogenesis but has no effect on stearoyl coenzyme desaturase activity in bovine subcutaneous adipose tissue

The primary objective of this study was to determine the effect of long-term feeding of whole cottonseed (WCS) on lipogenesis and stearoyl-coenzyme A desaturase activity in growing steers. Brangus steers were fed either a control, cornbased diet (n = 11) or 30% WCS (n = 12). The 30% WCS contributed an estimated 6.6% additional lipid to the diet. Steers fed the added WCS had greater live weights (P = 0.04) and kidney, pelvic, and heart fat (P = 0.005). Subcutaneous fat thickness was not different (P = 0.20) between treatment groups, although WCS elicited an increase in the proportion of large diameter subcutaneous adipocytes. The rate of [U-14C]acetate incorporation into fatty acids in subcutaneous adipose tissue was reduced by dietary WCS (171.4 vs 122.1 nmol x 100 mg adipose tissue-1 x 2 hr-1, P = 0.03), indicating that the increased dietary fat depressed de novo lipogenesis. Hepatic desaturase activity was much lower than that of subcutaneous adipose tissue, a feature common to cattle. We anticipated that added WCS also would depress stearoyl-coenzyme A desaturase activity in subcutaneous adipose tissue and liver due to its cyclopropene fatty acid content. Instead, desaturase activity was numerically (although not significantly) greater in liver (P = 0.37) and adipose tissue (P = 0.23).

Dietary fat and adipose tissue metabolism in ruminants, pigs, and rodents: a review

Effects of dietary fat on dairy cows are reviewed. Dietary fat did not affect gain in BW or body condition score after peak lactation but tended to increase BW loss during early lactation and body fat deposition in growing cattle. Dietary fat decreased de novo fatty acid synthesis in adipose tissue. Basal FFA release from adipose tissue in vitro and beta-adrenergic lipolytic responses were increased by protected polyunsaturated fatty acids. Dietary fat increased body fat in growing pigs and decreased BW loss in lactating sows. Dietary fat decreased de novo fatty acid synthesis and basal glycerol release in adipose tissue and tended to increase simultaneously beta-adrenergic lipolytic responses to increased membrane fluidity. Dietary fat increased body fat in rats. Polyunsaturated fatty acids were sometimes less efficient than saturated ones in increasing body fat. Lipoprotein lipase activity in adipose tissue generally decreased. Hepatic fatty acid synthesis was decreased sharply by polyunsaturated fatty acids, and adipose tissue response was less important. beta-Adrenergic-stimulated lipolysis decreased, and fatty acid esterification increased, particularly from saturated fatty acids. A trend toward insulin resistance, which was more marked with saturated fatty acids, occurred in adipose tissue.

Research note: effects of dietary fats on hepatic cholesterol synthesis in Japanese quail

Blood lipid concentrations and hepatic cholesterol synthesis were compared in Japanese quail fed diets containing fats with different fatty acid profiles. The quail fed a diet containing tuna oil had the lowest blood cholesterol concentration; those fed beef drippings the highest, and those fed safflower oil or linseed oil had intermediate concentrations. Rates of hepatic cholesterol synthesis mirrored the results for serum cholesterol concentration. Serum triglyceride concentrations were lower in the quail fed the two diets containing n-3 fatty acids in comparison with the beef and safflower treatment groups.

Effect of diet and substrate on the in vitro measurement of cholesterol and fatty-acid synthesis in hepatic tissue of Japanese quail

A comparison of acetate, glucose, mevalonate, or water as radioactive substrates for the hepatic synthesis of cholesterol, fatty acids, and glyceride-glycerol was made in Japanese quail fed diets containing either beef fat or tuna oil. The quail fed a diet containing beef fat were fatter and had a significantly higher (P less than .01) concentration of serum cholesterol (5.6 mM per L) than that measured in the serum of quail given tuna oil (4.1 mM per L). Both in vitro cholesterol and fatty-acid synthesis were greater in the quail fed a diet of beef fat than in those fed a diet containing tuna oil. The results showed that mevalonate was the most-suitable radioactive substrate for measuring cholesterol synthesis, whereas glucose was the most-suitable radioactive substrate for measuring fatty-acid and glyceride-glycerol synthesis.

Lipogenesis in liver and adipose tissue of the domestic cat (Felis domestica)

1. Production of fatty acids, CO2 and glycerol from glucose and acetate was determined in slices of liver and adipose tissue taken from mature cats. 2. Acetate was the predominant carbon source for de novo fatty acid synthesis in both liver and adipose tissue. 3. Fatty acid synthesis occurred at much greater rates in adipose tissue than in liver. 4. Relative lipogenic capacity (ratio of production of long-chain fatty acids and glycerol to oxidation of substrates) was 20 times greater in adipose tissue than in liver with both substrates.