Fatty Acid Composition Of Fish Research Articles

Effect of natural and artificial diets on seasonal changes in fatty acid composition and total body lipid content of wild and hatchery-reared Atlantic salmon ( Salmo salar L.) parr-smolt

Fatty acid composition of whole fish, stomach contents, gill, liver, and heart tissue, and total body lipids were determined in wild and hatchery-reared Atlantic salmon in August, November, and March–April during the year preceding their smolt out migration. The level of total body lipids was higher in reared than in wild fish. It decreased in the spring in both groups, a characteristic indicative of parr-smolt transformation. Also, the total amount of fatty acids in the selected tissues and stomach contents decreased during the winter and spring in both groups of fish. The fatty acid composition, as represented by the stomach contents, influenced the fatty acid composition of the fish. As a whole, the lipids of wild fish contained more saturates and less monoenes than those of reared fish. The proportion of the polyunsaturated fatty acid 20:5 was higher in wild than in reared fish while the 22:6 level was higher in reared than in wild fish. Only in March did the percentage of 22:6 in whole wild fish rise to the same level as in reared fish. The percentages of 22:6 and 20:5 decreased in liver and gills of wild fish in the spring: no such changes were found in reared fish.

MINIMIZATION OF FURTHER LIPID PEROXIDATION IN THE DISTILLATION 2‐THIOBARBITURIC ACID TEST OF FISH AND MEAT

ABSTRACTThe effect of adding propyl gallate (PG) and ethylenediaminetetraacetic acid (EDTA) in the distillation 2‐thiobarbituric acid (TBA) test of fish and meat samples was determined with the purpose of minimizing further oxidation of lipids during the test. Also determined was the effect of chilled blending on TBA values. The addition of PG and EDTA to the distillation mixture substantially lowered TBA values of catfish samples, while it did not show any significant effect on beef, pork, and chicken samples. Chilled blending also was effective for fish samples, although less effective than adding PG and EDTA in distillation; it did not have perceptible effect on meat samples. The addition of PG and EDTA in the blending process (the initial Step of the test) was most effective for both fish and meat samples. The differences in the results between fish and meat samples have been discussed in terms of general differences in fatty acid composition of fish and meat. Finally, the addition of PG and EDTA in the blending process is recommended in the distillation TBA test of fish and meat, particularly of fish, to minimize further lipid oxidation occurring during the test.

On the fatty acid composition of fish affected by excessive stress.

The flesh lipids of gilled and impounded sardine, Sardinops melanosticta, were compared. In gilled fish, the ratios of neutral lipids to phospholipids increased with a decrease of the latter. The acid values of the neutral lipids were significantly high in dead gilled fish. There was little difference between gilled and impounded fish in the fatty acid compositions (%) of either triglycerides or neutral lipids. The phospholipid fatty acids of gilled fish showed a remarkable decrease of 20:5 and 22:6 acids and an increase of 16:0 acid. The obvious decrease of polyenoic acids in the phospholipids of the gilled fish might be due mainly to a metabolic peculiarity under excessive stress.

Comprehensive evaluation of fatty acids in foods. VIII. Finfish

Recent (since 1960) data on the lipid content and fatty acid composition of fish were surveyed as part of the continuing USDA program to provide information on the nutrient composition of foods. Tabulated values of total lipid and fatty acids in finfish are presented. The most prominent fatty acids occurring in finfish are palmitic (C16:0), C18:1 (in some species C20:1 and C22:1), and the highly polyunsaturated C20:5 and C22:6. The general nutritional value of finfish is discussed. Two measures of polyunsaturation are presented for some commercially important domestic finfish: the total amount of polyunsaturated fatty acids (PFA) and the relative degree of polyunsaturation (PI).

Studies on nutrition of red sea bream. XII. Effect of .OMEGA.3 fatty acid supplement in a corn oil diet on fatty acid composition of fish.

Red sea bream fingerlings were kept on a corn oil diet, supplemented with 1% 18:3 ω3 and/or 2% ω3 polyunsaturated fatty acids (PUFA), and on a pollack residual oil diet. After a 45-day feeding trial, the general composition and the fatty acid composition of liver and muscle were determined. Fish fed on diets containing PUFA had higher contents of liver glycogen and muscle lipid than the fish fed the diet with or without the 18:3 ω3 supplement. Fatty acid analysis of liver phospholipid showed that the dietary 18:3 ω3 was converted into 22:5 ω3 and 22:6 ω3. Liver phospholipid of fish fed on diets with PUFA showed markedly higher level of 18:1 > fatty acids and lower levels of 20 < ω3 and 20 < ω6 fatty acids than those of fish fed the diets with 18:3 ω3, A relationship was recognized between the improve-ment of feed efficiency and the change in levels of 18:1 > fatty acids and 20<ω6 fatty acids in the liver phospholipid.