Effects of polyunsaturated fatty acids and some of their metabolites on mitotic activity of vascular smooth muscle explants from the coronary artery of rainbow trout (Oncorhynchus mykiss)

1997 ◽  
Vol 75 (1) ◽  
pp. 80-86 ◽  
Author(s):  
B. Gong ◽  
R. Townley ◽  
A. P. Farrell

This study is the first to examine the effects of polyunsaturated fatty acids and some of their metabolites on [3H]thymidine incorporation into vascular smooth muscle explants from the coronary artery of rainbow trout (Oncorhynchus mykiss). At a concentration of 120 μM, eicosapentaenoic acid (EPA; 20:5ω3), arachidonic acid (AA; 20:4ω6), and eicosatrienoic acid (ETA; 20:3ω6) all approximately doubled [3H]thymidine incorporation relative to controls. At a concentration of 20 μM, EPA had no significant effect, while ETA inhibited and AA caused an almost 5-fold increase in [3H]thymidine incorporation. The large mitogenic effect of 20 μM AA was completely inhibited by simultaneous addition of EPA to the culture medium. ETA only partially inhibited the mitogenic effect of 20 μM AA. Four AA-derived eicosanoids (or their stable analogues) were also tested. [3H]Thymidine incorporation was at least doubled with 1000 ng/mL carbacyclin (a prostacyclin analogue), 120 ng/mL prostaglandin F2α, and U-46619 (a thromboxane A2 analogue), but did not reach the level of stimulation produced by 20 μM AA. Leukotriene C4 had no significant effect. We conclude that dietary modulation of polyunsaturated fatty acids (PUFAs) in salmonids could have significant effects on coronary vascular smooth muscle mitosis through the incorporation of PUFAs into cell membranes and the production of eicosanoids.

1994 ◽  
Vol 51 (6) ◽  
pp. 1391-1400 ◽  
Author(s):  
Xiuwei Yang ◽  
Terry A. Dick

Juvenile Arctic char (Salvelinus alpinus) and rainbow trout (Oncorhynchus mykiss) were fed one commercial and three casein-based diets varying in amounts of 18:2n-6 and 18:3n-3, two polyunsaturated fatty acids (PUFA), for 12 wk at 10 °C. Both species on the diet without PUFA had lower specific growth rate (SGR) but higher percentages of liver neutral lipids and 20:3n-9 in liver polar lipids than those fed high PUFA content or commercial diets. Regardless of the amount of 18:3n-3 in the diets, the percentages of 20:3n-9 and 20:3n-9/22:6n-3 in liver or muscle polar lipids were significantly lower in char than in trout; values in trout were lower than reported in other studies. These findings question the use of 20:3n-9/22:6n-3 as an indicator of essential fatty acid status for both species. Different levels of 20:3n-9, 22:6n-3, and other PUFAs in tissue polar lipids of the two species suggest that Δ6 and/or Δ5 desaturases are less efficient in char. While trout fed test diets had slightly less 20:4n-6 than wild trout, char had 1/10 less 20:4n-6 in muscle polar and total lipids than wild char, suggesting that char may require n-6 and n-3 PUFA in their diet for optimal performance.


1995 ◽  
Vol 73 (4) ◽  
pp. 623-631 ◽  
Author(s):  
Bang Q. Gong ◽  
Anthony P. Farrell

A standardized method of in vitro [3H]thymidine incorporation during the S phase of cell division was developed to study vascular smooth muscle proliferation in the coronary artery of rainbow trout (Oncorhynchus mykiss). We established a reliable medium system, an optimum [3H]thymidine dose, and optimum incubation conditions. Incorporation of the radiolabel into vascular smooth muscle nuclei was confirmed with autoradiography. To test the sensitivity of the assay system, the coronary artery was surgically exposed and gently rubbed in anesthetized rainbow trout. Following either a 1-, 2-, or 3-day recovery period, fish were sacrificed and the coronary artery explants were cultured with [3H]thymidine. Gentle rubbing of the coronary artery in vivo resulted in a significant increase in [3H]thymidine incorporation into the coronary artery explant compared with sham-operated and untreated control groups of fish. Peak incorporation of [3H]thymidine occurred at day 2 in the treated group, when incorporation was three times that in the sham-operated group. This technique has potential application in the study of coronary arteriosclerosis in salmonids, where vascular smooth muscle proliferation is a primary event.


Animals ◽  
2021 ◽  
Vol 11 (2) ◽  
pp. 456
Author(s):  
Amélie Bélanger ◽  
Pallab K. Sarker ◽  
Dominique P. Bureau ◽  
Yvan Chouinard ◽  
Grant W. Vandenberg

Aquaculture feed formulation has recently turned its focus to reduce the reliance on marine-derived resources and utilise alternative feedstuffs, as an approach to improve the environmental sustainability of the aquaculture sector. The fish oil market is highly volatile, and availability of this commodity is continuously decreasing for use in aquaculture. Currently, a growing number of commercial efforts producing microalgae are providing omega 3-rich oil for sustainable aquaculture feed. This study was focused to determine the nutrient digestibility of a marine microalga, Schizochytrium spp., which is rich in docosahexaenoic acid (DHA) and long-chain polyunsaturated fatty acids (LC-PUFA), as a novel dietary lipid source that could be utilized effectively by rainbow trout (Oncorhynchus mykiss). A whole-cell Schizochytrium spp. biomass was used in the digestibility experiment at two different temperatures, 8 °C and 15 °C. No significant differences were detected between the two temperatures for the apparent digestibility coefficients (ADCs) of the dry matter (94.3 ± 4.9%), total lipids (85.8 ± 0.0%), crude proteins (89.5 ± 1.8%), energy (83.1 ± 1.7%) and fatty acids (85.8 ± 7.5%). The ADCs of the nutrients, energy, DHA and other fatty acids showed that Schizochytrium spp. is a high-quality candidate for fish oil substitution and supplement of LC-PUFA in fish feed with vegetable oils.


1989 ◽  
Vol 256 (4) ◽  
pp. H968-H973 ◽  
Author(s):  
H. Shimokawa ◽  
P. M. Vanhoutte

Dietary supplementation with cod-liver oil significantly augments endothelium-dependent relaxations in porcine coronary arteries. The present study was designed to examine the effect of dietary administration of omega 3 polyunsaturated fatty acids (mainly eicosapentaenoic acid, the major component of fish oil) on endothelium-dependent relaxations in porcine coronary arteries. Male Yorkshire pigs were maintained 4 wk on a regular diet with or without supplementation with purified eicosapentaenoic acid (3.5 g/day) and docosahexaenoic acid (1.5 g/day). Endothelium-dependent relaxations were examined in vitro. In rings from the treated group, endothelium-dependent relaxations were augmented in response to bradykinin, serotonin, and ADP, but not to the calcium ionophore A23187. These augmentations were not altered by indomethacin but were significantly inhibited by methylene blue, an inhibitor of guanylate cyclase. In the treated group, endothelium-dependent relaxations to aggregating platelets also were significantly augmented; platelet-induced contractions of quiescent rings were inhibited more by the presence of the endothelium than in arteries from the control group. Bioassay experiments demonstrated that the release of endothelium-derived relaxing factor(s) by bradykinin and relaxations of the vascular smooth muscle to the factor(s) were greater in arteries from the treated group. These observations indicate that dietary omega 3 polyunsaturated fatty acids augment receptor-operated endothelium-dependent relaxations, partly due to the augmented release of endothelium-derived relaxing factor(s) and partly due to the augmented relaxation of the vascular smooth muscle to the factor(s).


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