Chain-length specificities of mitochondrial and peroxisimal β-oxidation of fatty acids in livers of rainbow trout (Salmo gairdneri)

The specificity of acyl-coenzyme A (CoA): lysophosphatidylcholine acyltransferase (LPCAT; EC 2.3.1.23) was determined for a range for acyl-CoA substrates differing with respect to chain length and degree of unsaturation in liver microsomes of thermally acclimated (5 and 20 degrees C) rainbow trout, Salmo gairdneri. Absolute levels of oleate incorporation into phosphatidylcholine (PC) were determined at substrate concentrations in the physiological range (12 microM) and higher (64 microM). The specificity of LPCAT was determined by the extent to which competing substrates decreased the incorporation of oleate. LPCAT specificity was significantly influenced by both assay and acclimation temperature at total substrate concentrations of both 72 and 256 microM. A clear preference for 14- and 16-carbon monoenes was exhibited by LPCAT from 20 but not 5 degrees C-acclimated trout. Furthermore, LPCAT from 5 degrees C-acclimated trout preferentially incorporated long chain and polyunsaturated fatty acids (eicosadienoyl, arachidonoyl, erucoyl) and excluded 18-carbon unsaturates at an assay temperature of 5 degrees C compared with 20 degrees C; at 20 degrees C, 18-carbon unsaturates were incorporated more readily than 20-carbon species. Linolenic acid (18:3N3) was generally excluded from incorporation, reflecting a possible mechanism by which this precursor of docasahexaenoic acid (22:6N3, n - 3) remains available for modification. These results indicate that trout liver LPCAT preferentially incorporates fatty acids into PC on the basis of both chain length and degree of unsaturation in a manner consistent with the temperature-induced restructuring of membrane phospholipids.

Download Full-text

Dietary Factors and Hepatoma in Rainbow Trout (Salmo gairdneri). II. Cocarcinogenesis by Cyclopropenoid Fatty Acids and the Effect of Gossypol and Altered Lipids on Aflatoxin-Induced Liver Cancer23

JNCI Journal of the National Cancer Institute ◽

10.1093/jnci/41.6.1293 ◽

1968 ◽

Cited By ~ 1

Keyword(s):

Fatty Acids ◽

Rainbow Trout ◽

Liver Cancer ◽

Dietary Factors ◽

Salmo Gairdneri ◽

Cyclopropenoid Fatty Acids

Download Full-text

Liver Damage in Rainbow Trout (Salmo gairdneri) Fed Cyclopropenoid Fatty Acids

Journal of the Fisheries Research Board of Canada ◽

10.1139/f74-166 ◽

1974 ◽

Vol 31 (8) ◽

pp. 1397-1400 ◽

Cited By ~ 4

Author(s):

Y. Malevski ◽

J. H. Wales ◽

M. W. Montgomery

Keyword(s):

Fatty Acids ◽

Rainbow Trout ◽

Liver Damage ◽

Basal Diet ◽

Experimental Period ◽

Salmo Gairdneri ◽

Histological Changes ◽

Cyclopropenoid Fatty Acids ◽

Cyclic Changes ◽

Parenchymal Cells

Histological changes in livers of rainbow trout (Salmo gairdneri) repeatedly fed diets containing cyclopropenoid fatty acids (CPFA) revealed that these fish were unable to develop resistance to liver damage caused by CPFA. One group of trout was fed 150 ppm CPFA in the basal diet for 49 days followed by the basal diet for the remainder of the experimental period. Another group of trout was fed 150 ppm CPFA for 49 days, basal diet for 65 days, and 150 ppm CPFA for 45 days. At this time this group was divided into two subgroups; one received basal diet for 15 days, the other for 30 days, after which both subgroups were placed on a diet containing 360 ppm CPFA for 36 days. Analysis of the livers for histological changes showed that the parenchymal cells underwent cyclic changes of injury and recovery each time the trout were fed CPFA. Complete recovery of parenchymal cells occurred after the fish were removed from the diets containing CPFA for 30 days. Bile duct and blood vessel hyperplasia was observed for as long as 7 mo after CPFA was eliminated from the trout diet.

Download Full-text

Use of Synthetic Diets and Biochemical Criteria in the Assessment of Nutrient Requirements of Fish

Journal of the Fisheries Research Board of Canada ◽

10.1139/f76-132 ◽

1976 ◽

Vol 33 (4) ◽

pp. 1040-1045 ◽

Cited By ~ 32

Author(s):

C. B. Cowey

Keyword(s):

Fatty Acids ◽

Rainbow Trout ◽

Magnesium Deficiency ◽

Scophthalmus Maximus ◽

Salmo Gairdneri ◽

Response Curves ◽

Dietary Magnesium ◽

Carbon Acids ◽

Acid Status ◽

Turbot Scophthalmus Maximus

Dietary allowances of nutrients have been formulated mainly from growth–response curves. The use of other criteria, especially those which exploit the biochemical role of nutrients, is discussed by reference to three different nutrients, namely thiamin, magnesium, and essential fatty acids.It is shown that erythrocyte transketolase activity provides a nutritional index of thiamin status in turbot (Scophthalmus maximus). The enzyme is saturated with coenzyme (thiamin pyrophosphate) at a dietary thiamin level of 2.6 mg/kg.Assessment of mineral requirements is shown to present special problems because complex interrelationships exist between some dietary minerals. It is shown that dietary magnesium deficiency (4 mg magnesium/100 g diet) leads to renal calcification in rainbow trout (Salmo gairdneri) at dietary calcium levels of 2.7 g/100 g (Ca: P ratio 1: 1). Elevation of dietary magnesium to 100 mg/100 g under these conditions gave freedom from pathology and enhanced growth.Ratios of certain fatty acids in the tissue phospholipids of rainbow trout are known to provide a useful index of essential fatty acid status. These ratios cannot be applied to turbot as this species does not chain elongate and desaturate 18-carbon acids at appreciable rates. Long chain polyunsaturated fatty acids of the ω3 series must be supplied preformed in the diet of turbot.

Download Full-text

Glycerylphosphorylcholine and Related Compounds in Rainbow Trout Muscle Stored at −4 C

Journal of the Fisheries Research Board of Canada ◽

10.1139/f67-027 ◽

1967 ◽

Vol 24 (2) ◽

pp. 273-280 ◽

Cited By ~ 5

Author(s):

R. E. E. Jonas ◽

E. Bilinski

Keyword(s):

Fatty Acids ◽

Rainbow Trout ◽

General Trend ◽

Fish Muscle ◽

Enzymic Activity ◽

Salmo Gairdneri ◽

Threefold Increase ◽

Free Choline ◽

Related Compounds ◽

Trout Muscle

Glycerylphosphorylcholine in rainbow trout (Salmo gairdneri) muscle stored at −4 C showed an increase from 36 μmoles/100 g in fresh muscle to 46 μmoles/100 g after 2 weeks. During longer periods of storage an approximately threefold increase in concentration took place, reaching 123 and 105 μmoles/100 g muscle after 9 and 17 weeks. Liberation of free choline was found to take place after 6 weeks of storage. There was very little change in the concentration of choline after 6 weeks storage when the value was approximately 100 μmoles/100 g. The release of free fatty acid during cold storage showed a general trend, which was similar to the formation of glycerylphosphorylcholine, but quantitatively the changes were more pronounced. Free fatty acids amounted to 45 μmoles/100 g in fresh muscle and rose to a plateau of approximately 1200 μmoles/100 g after 9 weeks of storage. The results are discussed in relation to the enzymic activity present in fish muscle.

Download Full-text