The effect of excess cobalt on milk fatty acid profiles and transcriptional regulation of SCD, FASN, DGAT1 and DGAT2 in the mammary gland of lactating dairy cows.

The main objective of this study was to investigate the effect of excess cobalt (Co) on gene expression of stearoyl-CoA desaturase (SCD), fatty acid synthase (FASN), diacylglycerol acyltransferase 1 (DGAT1) and diacylglycerol acyltransferase 2 (DGAT2) of lactating dairy cows in relation to milk fatty acid profile. Seven multiparous cows of the Norwegian Red cattle breed (NRF) had their basal diet supplemented with 1.4 g Co as a 24 g/l solution of Co-acetate per os twice daily for 7 days followed by a 9-day depuration period. Udder biopsies were performed prior to the treatment period, after 1 week of treatment and immediately after the depuration period. Excess Co reduced the proportion of all cis-9 monounsaturated fatty acids and increased the proportion of 18:0 in milk. However, gene expression levels of SCD, DGAT1, DGAT2 and FASN were not significantly altered. Our results indicate that the effect of Co on milk fatty acid profile is mediated at the post-transcriptional level by reduced activity of SCD in the mammary gland. Potential mechanisms explaining how Co might reduce stearoyl-CoA desaturation are discussed.

Cobalt reduces the Δ9-desaturase index of sow milk.

The main objective of this study was to examine if cobalt (Co) reduces Δ(9) -desaturase indices in milk and blood lipids in sows. The experimental design consisted of a repeated measurement consisting of a pre-treatment period of a minimum of 9 days, a treatment period of 5 days and a post-treatment period of 6 days. Experimental animals consisted of 10 lactating sows; five sows had an intramuscular injection of 59 mg Co diluted in 5 ml 0.9% saline solution twice a day, whereas the other five had an intramuscular injection of 5 ml 0.9% saline solution twice a day as a control. Milk Δ(9) -desaturase indices for cis-9 18:1, cis-9 16:1 and cis-9 14:1 were significantly reduced (p < 0.0001) as a result of the Co-treatment, contrasting with the plasma Δ(9) -desaturase indices, which were unaffected. Potential mechanisms explaining how Co might reduce milk Δ(9) -desaturase indices are discussed. Moreover, the toxicological level of Co and potential implications of using Co-ethylenediaminetetraacetic acid as a liquid marker in digestibility experiments are addressed.

Intravenous injections of cobalt reduce fatty acid desaturation products in milk and blood of lactating cows.

The objective of this study was to determine whether intravenous infusion of Co affects levels of fatty acid desaturation products in bovine milk. Six cows were assigned to two replicated 3 × 3 Latin squares with 14-day periods. Treatment occurred on days 1 to 5 and depuration occurred on days 6-14. Two treatments were tested, the first consisting of per os supplementation of 3.5 g Co daily in the form of Co acetate and the second consisting of intravenous injection of 175 mg Co daily in the form of Co acetate diluted in saline solution. The third treatment was a control. Both Co treatments decreased cis-9 18:1 levels from approximately 18 to 14 g/100 g fatty acids, and increased 18:0 levels from 11 to 17 g/100 g fatty acids in milk fat (p < 0.001). The proportions of cis-9 10:1, cis-9 12:1, cis-9 14:1, cis-9 16:1 and cis-9 17:1 decreased (p < 0.001), whereas 17:0 and trans-11 18:1 increased (p < 0.001). In blood plasma, levels of cis (6,9,12) 18:3 (p < 0.001) and cis (8,11,14,17) 20:4 (p = 0.008) decreased after both the Co treatments. It is concluded that intravenous supply of Co reduces levels of fatty acid desaturation products in both bovine milk and blood.

Fatty acid composition of serum lipids in atopic and healthy dogs.

Fatty acids are increasingly used in the treatment of canine atopic dermatitis and their beneficial effects are documented in several prospective, controlled studies. Results from recent studies have indicated that atopic dogs have disordered fat metabolism, due to decreased desaturase activity. To further clarify these possible abnormalities, we examined serum fatty acid patterns in dogs with atopic dermatitis and normal controls. Atopic dermatitis was diagnosed according to the diagnostic criteria proposed by Willemse, after elimination of other possible causes of pruritic dermatitis. Both the relative and the absolute amounts of fatty acids in sera were determined by gas chromatography. Differences in the serum fatty acid pattern indicating a reduction in desaturase activity were not detected in atopic dogs when compared with controls.

The fatty acid profile of subcutaneous fat and blood plasma in pruritic dogs and dogs without skin problems.

The purpose of this study was to investigate the concentration of polyunsaturated fatty acids (PUFAs) in subcutaneous fat and the relative amounts of PUFAs in plasma in two groups of dogs. Group 1 included dogs with a good skin and coat condition. Group 2 was comprised of dogs with pruritus and compatible clinical signs of atopy. The fatty acid composition of the total lipid fraction was analyzed by gas chromatography. In subcutaneous fat, the concentration of adrenic acid (22:4n-6) was lower in the group of pruritic dogs compared to dogs with healthy skin. The amount of dihomogammalinolenic acid (20:3n-6; DGLA) in plasma lipids from pruritic dogs was higher than in dogs without skin problems.

Fatty acid composition of porcine muscle and adipose tissue lipids as affected by anatomical location and cod liver oil supplementation of the diet.

In pigs fed a standard pig mash the contents of polyunsaturated fatty acids (PUFAs) of both the n-6 and n-3 series were significantly higher in the dark red mm adductores compared to the light coloured m longissimus lumborum. Perirenal fat had a higher concentration of saturated fatty acids (14:0, 16:0, 18:0) than backfat, and a lower concentration of monounsaturated fatty acids, such as 16:1n-7 and 18:1n-9. Daily supplementation of 50 ml cod liver oil, rich in n-3 PUFAs, during the fourth and third week before slaughter led to a 1.4 to 1.7 times increase in the contents of n-3 PUFAs in muscles and fat depots. There was no difference between the incorporation of n-3 PUFAs in dark and light muscles. Perirenal fat contained more 20:5n-3 (EPA) and 22:6n-3 (DHA), but less 20:1n-9 (eicosenoic acid) than the backfat, after cod liver oil supplementation rich in these 3 fatty acids. Supplementation of cod liver oil reduced the n-6/n-3 fatty acid ratio in all anatomical locations examined.

An experimental study on transcutaneous absorption of ethylesters of eicosapentaenoic acid (EPA; 20:5n-3) and docosahexaenoic acid (DHA; 22:6n-3) in pigs.

Twenty-two pigs with an average weight of 24.2 kg were divided into two groups. Five grams of an ointment containing 40% of the n-3 polyunsaturated fatty acids, eicosapentaenoic acid (EPA; 20:5n-3) and docosahexaenoic acid (DHA; 22:6n-3) as ethylesters, was administered cutaneously to the experimental group and orally to the control group twice daily over a 3 day period. Surgical biopsies of subcutaneous fat of all 22 pigs were taken before and after the ethylester administration period. Blood samples were taken from the jugular vein. Skin biopsies were taken after the application period, and the presence of pathological features and inter-animal variation were noted. No increase of EPA and DHA in subcutaneous fat was found in either group. In the oral group the content of EPA had increased in the total plasma lipids on the first day after the end of the experiment. It is concluded that a rapid transcutaneous absorption of EPA and DHA as ethylesters does not seem to occur in pigs.

A preliminary study on the effect of dietary supplementation with cod liver oil on the polyunsaturated fatty acid composition of boar semen.

Eight mature Norwegian Landrace boars, of proven fertility and in routine semen production for AI, were fed individually with the same basic diet for 9 weeks. One group of 4 animals served as the control, the remaining 4 boars received a daily supplement of 75 ml cod liver oil (CLO-group). Fifteen consecutive semen samples were collected from each boar. The fatty acid composition of the semen was determined, and the content of the 15 most numerous fatty acids with a chain length longer than 12 carbon atoms was followed over time. In both groups, the proportion of 16:1n-7 decreased significantly, while 16:0 and 22:6n-3 (DHA) increased. By the end of the experiment, DHA had tended to increase and 22:5n-6 to decrease to a greater extent in the CLO-group. A significant difference between the groups was seen for one n-6 PUFA (22:4n-6), which remained unchanged in the control group but decreased in the CLO-group. No change was seen in docosapentaenoic acid (22:5n-3) and eicosapentaenoic acid (20:5n-3) was not found in any sample. These results indicate that CLO supplementation affects the fatty acid composition of boar semen. There were no significant differences in the non-return rates (4-25 days) between the two groups before, during or after the experiment.

Cobalt supplied per os reduces the mammary Delta9-desaturase index of bovine milk.

Results indicated that the dual marker system of Yb-acetate and Co-EDTA supplied per os reduced the proportion of fatty acids in bovine milk that were products of Delta (9)-desaturase. To verify this effect and identify the responsible marker component, 18 cows (3 cows per treatment) were administered per os a 0.25-L solution of either Co-acetate, Co-EDTA, Co-EDTA + Yb-acetate, EDTA, Yb-acetate, or water twice daily for 5 d. The daily amounts of Co, Yb, and EDTA were, respectively, 3.50, 3.44, and 21.00 g per cow. Milk and blood were sampled and analyzed for content of fatty acids, and blood was sampled and analyzed for Co and cobalamin. Only solutions containing Co had a reducing effect (P < or = 0.01) on fatty acids that were products of Delta(9)-desaturase in milk--cis-9 10:1, cis-9 14:1, cis-9 16:1, cis-9, trans-11 18:2, and cis-9 18:1--with the exception of the solution containing Co-EDTA + Yb-acetate for cis-9 18:1. Of the substrate fatty acids of Delta (9)-desaturase, only 18:0 increased (P < 0.001) in all groups supplied with Co-containing solutions. Thus, Co had a reducing effect (P < or = 0.004) on the Delta (9)-desaturase indices [(product of Delta(9)-desaturase)/(product of Delta(9)-desaturase + substrate of Delta(9)-desaturase)] of milk for cis-9 14:1, cis-9 16:1, cis-9 18:1, and cis-9, trans-11 18:2. There were no differences in Delta(9)-desaturase indices between Co-EDTA and Co-acetate. None of the marker solutions influenced the fatty acid composition of blood plasma, and Co was detected only in the blood samples from cows treated with solutions containing Co. On the basis of these results, we concluded that Co given per os decreased the Delta(9)-desaturase indices of bovine milk.

Omega-3 fatty acid incorporation in fat and muscle tissues of growing pigs, fed supplements of fish oil.

Fifteen pigs from two litters of Norwegian Landrace were divided into three groups of five animals. The pigs were fed individually the same basic diet for 64 days, one group serving as control, the two other groups receiving daily supplements of 5 and 20 g fish oil, respectively. Biopsies were taken from subcutaneous fat and muscle tissues on day 0, 3, 8, 16 and 32. Samples were also collected from animals slaughtered on days 64 and 78. In fat tissue from pigs given a daily dose of 20 g fish oil containing 30% eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA) as triglycerides, the concentrations of EPA and DHA were significantly increased above the levels in the control animals over the 32 days period. Unexpectedly, there was also a significant increase in docosapentaenoic acid (DPA), in spite of the very low level of this fatty acid in the fish oil. In fat tissue from pigs given 5 g fish oil the contents of EPA and DPA were significantly increased. Also in muscle tissue from pigs given a daily dose of 20 g fish oil, the concentration of EPA, DPA and DHA were significantly elevated above the level of the control group over the 32 days period. In muscle tissue from pigs given 5 g fish oil only the contents of EPA were significantly increased. There was a positive correlation between the dose of fish oil and the concentrations of omega-3 polyunsaturated fatty acids in both fat and muscle tissues.(ABSTRACT TRUNCATED AT 250 WORDS)

Supplements of cod liver oil to lactating sows. Influence on milk fatty acid composition and growth performance of piglets.

Twelve sows received a supplement of 50 ml cod liver oil, without vitamin A and D, daily from day 107 of gestation until weaning. Eight sows served as control. A milk sample was obtained from each sow at parturition and on day 14 of lactation. The piglets were weighed at birth, on days 7, 14 and on the day of weaning. Eicosapentaenoic acid (20:5, n-3) (EPA), docosahexaenoic acid (22:6, n-3) (DHA) and docosapentaenoic acid; (22:5, n-3) (DPA) were found in milk fat from all sows. At parturition the contents of EPA, DPA and DHA were significantly higher in the group given cod liver oil supplement. After 2 weeks of lactation only EPA and DHA were elevated compared with the non-supplemented group. No effect on weight gain or on the overall morbidity of the piglets was found. The animal health in this farm was very good, and the growth rate faster than the average for Norwegian pigs.