Application of Carbowax 20M as an open-tubular liquid phase in analyses of nutritionally important fats and oils

Lipids and fatty acids of two pelagic cottoid fishes (Comephorus spp) endemic to Lake Baikal

Matured females of two Lake Baikal endemic fish species, Comephorus baicalensis and Comephorus dybowski, have been investigated for lipid of the whole body and specific tissues (liver, muscles, ovaries), phospholipid classes and fatty acids of neutral and polar lipids. Total lipid in the body (38.9% fresh weight), liver (23.5%) and muscles (14.5%) of C. baicalensis were greater than those of C. dybowski (4.7, 8.7 and 2.6%, respectively); only their ovaries were similar (5.3 and 5.6% lipid, respectively). In both species, phosphatidylcholine and phosphatidylethanolamine were the major phospholipids, ranging from 60.7 to 75.1% of total phospholipid and 14.5-25.7%, respectively. In most cases, monounsaturated fatty acids (MUFA) were the major fatty acid group in C. baicalensis, whereas polyunsaturated fatty acids (PUFA) were the major group in C. dybowski. The MUFA 18:1(n-9) prevailed over other fatty acids in C. baicalensis and varied from 19% in polar lipids of muscles to 56.1% in neutral lipids of muscles. In polar lipid of C. dybowski, the PUFA 22:6(n-3) prevailed over other fatty acids in muscles and ovaries, while 16:0 dominated polar liver lipids and neutral lipids of all tissues. Other major fatty acids included 16:1(n-7), 18:1(n-7), and 20:5(n-3). Values of the (n-3)/(n-6) fatty acid ratio for neutral lipids of C. baicalensis (0.5-0.9) are well below the range of values characteristic either for marine or freshwater fish, while these values for polar lipids (1.6-1.8) are in the range typical of freshwater fish. Neutral lipid fatty acid ratios in C. dybowski (2.5-3.1) allow it to be assigned to freshwater fish, but polar lipids (2.8-3.7) leave it intermediary between freshwater and marine fish.

Bimodal action of fatty acids on PMA-stimulated O2.- production in human adherent monocytes

Not only unsaturated linear fatty acids, but also saturated monomethyl-branched fatty acids (MMBFAs), are provided by food. They are capable of penetrating into the membrane lipids and promoting lipid disorder. Both NADPH oxidase and protein kinase C (PKC) are bound to cell cytoplasmic membranes and are responsive to unesterified fatty acids (UEFAs). We found that the O2.- NADPH oxidase-mediated production of human adherent monocytes was modified by unsaturated linear and saturated branched UEFAs only in the presence of phorbol myristate acetate. This result together with our inhibition data indicated an action strictly linked to PKC activity. The type and intensity of action depended on the UEFA concentrations and chain structure. Nanomolar concentrations showed potentiating effects whereas micromolar (< CMC) concentrations displayed depressant influences MMBFAs were generally more active than the other FAs. With respect to the micromolar depressant effect, oleate and linoleate were as active and docosahexaenoate nearly as active as MMBFAs. As assessed by iso-15:0 or arachidonate action, such bimodal alteration did not occur in non-adherent monocytes and neutrophils. Certain UEFAs could be considered as 'cellular' anti-oxidants on the sites of adherent-monocyte recruitment.

The heptadecanoic fatty aldehyde--one of the main aldehydes of the far-eastern Bryozoa

1. The relative content of 16:0, 17:0 and 18:0 fatty aldehydes in the lipids of eight species of the far-eastern Bryozoa was studied. 2. Heptadecanoic aldehyde is one of the main aldehydes in the seven species investigated comprising about 30% of the sum of these main bryozoan aldehydes. 3. We suggest the unusually high relative heptadecanoic aldehyde content in the lipids of Bryozoa may be helpful in settling some problems concerning their system.

Changes in lipid content, fatty acid composition and lipoprotein lipase activity in dry goat omental adipose tissue according to tissue site

Water and lipid contents, fatty acid distribution, and lipoprotein lipase activity were determined in 11 samples taken from the Omentum Majus of five dry Alpine goats. Samples were chosen to standardize sampling sites using geometric guide marks representative of different adipose tissue sites. Sample location explained between 20% and 30% of the total variance in water and lipid contents and in lipoprotein lipase activity, and from 5.5% to 45.4% of the total variance in fatty acid distribution. Increased sample thickness was associated with an increase in lipid content and in saturated fatty acid percentages. Samples taken in proximity of the omentum tissue attached to the rumen and abomasum had the highest content. We furthermore found that the levels of 18:2n-6, 18:1n-7, and of branched chain fatty acids were high close to a pila of the rumen which also corresponded to high lipoprotein lipase activity. Concomitant high levels of 16:1n-7, 17:1n-8, and 18:1n-9 may reflect high levels of delta 9 desaturase activity.

Effect of intragastric triglyceride administration on glucose homeostasis in newborn pigs

The fasting hypoglycemia (1.78 +/- 0.29 mmol/l) which develops in 48-h-old pigs is partially reversed (3.85 +/- 0.55 mmol/l) after gastric administration of long-chain triglycerides (LCT). The increase in blood glucose induced by LCT feeding was not secondary to a decreased glucose utilization because glucose disappearance rate increased in LCT-fed piglets but resulted from a twofold increase in glucose appearance. By using the crossover-plot technique, the stimulation of hepatic gluconeogenesis induced by LCT feeding has been localized at 1) the level of pyruvate carboxylase owing to the twofold increase in hepatic acetyl-CoA concentration and 2) the level of glyceraldehyde-3-phosphate dehydrogenase secondary to the increase in reducing equivalents (NADH), which displaces this equilibrium reaction in the direction of gluconeogenesis. As blood lactate, pyruvate, and alanine concentrations increased after LCT feeding, the possible effects of LCT on pyruvate dehydrogenase in peripheral tissues are discussed. These data demonstrate that fatty acids stimulate hepatic gluconeogenesis in 48-h-old fasting piglets and underline the role of fat provision in the regulation of glucose homeostasis during the neonatal period in the pig.

Fatty acid and squalene compositions of Mediterranean Centrophorus SPP egg and liver oils in relation to age

The liver oil content of seven Mediterranean Centrophorus spp. were studied together with the oil of one unfertilized egg and one yolk bag. The relative weight of the liver ranges from 15 to 29% of total body weight; 63 to 89% of the liver weight is oil. Squalene, the major component (49-89% in oil) of the unsaponifiable fraction, is directly quantified by GLC following TLC separation. The squalene level increases with the age of the animals. More than 50 fatty acid species were identified. Among them, the most abundant are: 16:0 (22-27%), 18:1 omega 9 (21-36%) and 22:6 omega 3 (2-18%). The level of omega 3-fatty acids, essential in the fishes, shows a maximum in the egg (26%), decreases to a minimum in the young (5%) and stabilizes to an intermediate level in the adult (12%).

A comparison of the lipoprotein profiles in male trout (Salmo gairdneri) before maturity and during spermiation

1. The distribution and concentration of blood lipoproteins were determined in three groups of male rainbow trout (Salmo gairdneri) each, fed the same diet and reared at a temperature of 17-18 degrees C. 2. The three groups (A, B and C) differed as to age (A and B were 1 yr old, while C was 3 yr old) and to degree of sexual maturity (A was sexually immature, while B and C were in spermiation). 3. Total serum lipoprotein levels reached high values in A, B and C (1900, 2400 and 1500 mg/100 ml. respectively) but their distribution depended largely on the degree of sexual maturity of the fish. 4. Very low density lipoproteins (VLDL) and low density lipoproteins (LDL) were predominant in juvenile trout, whereas high density lipoproteins (HDL) accounted for more than 50% of the total lipoproteins in spermiating trout. 5. In the latter class of lipoproteins, the phospholipid comprised 70% of the total lipid. 6. Essential 22:6 (n-3) was the main polyunsaturated fatty acid in all the lipid fractions of each of the lipoprotein classes; it was found in higher percentages in structural lipid, phospholipid and cholesterol ester, comprising between 35 and 40% of the total fatty acids. 7. These findings support the hypothesis that the production and utilization of lipoproteins in trout are related to the annual formation of gonadal tissue. The lipoproteins might be vehicles for cholesterol and essential fatty acid 22:6 (n-3), incorporated into gonadal tissue during gametogenesis.

Effect of dietary fatty acids differing by chain lengths and omega series on the growth and lipid composition of turbot Scophthalmus maximus L

1. A previous paper (Gatesoupe et al., 1977) showed that turbot had a specific requirement for omega 3HPUFA since equivalent dietary amounts of 18:3 omega 3 or omega 3HPUFA (0.55% of the diet) did not lead to the same growth performances. 2. In the present paper, we demonstrated that fish given a high level of dietary 18:3 omega 3 (3.7% of the diet), without omega 3HPUFA, presented better growth than those offered a lower level of 18:3 omega 3, and almost the same performances as fish receiving 0.57% omega 3HPUFA. 3. This suggested that turbot, like trout, might be able to use the 18:3 omega 3 as a precursor of the omega 3 series. Furthermore, according to the present relatively short-term experiment, elongation-desaturation reactions of the omega 3FA did not appear to be reduced with low dietary omega 3FA levels. 4. On the other hand, these types of reactions seemed to be totally missing with the 18:2 omega 6. Thus, it may be assumed that there was no direct relationship between growth and omega 3 elongating-desaturating activities, and that omega 3 lowering fish body content was not the cause, or at least not the only cause, of poor growth in long-term experiments.

Effects of two different medium-chain triglycerides (tri C8:O and tri C12:O) on liver lipids in the growing rat

Results presented in this study emphasize the long-term effects of dietary fatty acid chain length on some biochemical parameters of the liver in the growing rat. High levels of medium-chain fatty acids feeding (C8:O and C12:O) from 40 to 340 g of body weight induced liver growth and lipid contents intermediary between values recorded with a lipid-free diet and with a diet containing long-chain fatty acids. No steatosis was recorded but neutral lipid contents appeared to be correlated with the dietary fatty acid chain length while phospholipid contents remained much more stable. In the four tested nutritional conditions, only dodecanoïc or lauric acid (C12:O) feeding induced important alterations in the fatty acid pattern of liver neutral lipids. Medium-chain fatty acids, and even lauric acid which was intensely esterified in adipose tissue triglycerides, did not appreciably modify the fatty acid composition of liver phospholipids and were not esterified in it.

Comparison of long term lipogenic effects of two different medium-chain triglycerides (tri C8: O and tri C12 : O) in the growing rat

During the growth (35 g-340 g), and as compared to results obtained with a lipid-free diet or a diet containing long-chain fatty acids, high levels of Tri C8 : O or Tri C12 : O did not change the quantitative aspects of proteinogenesis and lipogenesis balances. The incorporation of Tri C8 : O into the diet did not change the fatty acid composition of body lipid stores while the incorporation of Tri C12 : O induced a lipogenesis characterized by the disappearance of about 50% of the n-9 and n-7 unsaturated fatty acids, the emergence of an equivalent amount of saturated fatty acids in C12 and C14, and the decrease of hexadecanoic or palmitic acid concentration. Titers of saturated fatty acids with a melting point higher than 40 degrees C increased from 34% to 64%. Results suggested an efficient inhibition of fatty acid biosynthesis de novo by C12 : O, associated with an impossibility for microsomal enzymes to assume the elongation of a sufficient amount of C12 : O to maintain C16 : O concentration and to furnish an important amount of substrate (C18 : O) to delta-9-stearoyl coenzyme A desaturase for oleic acid synthesis. Introducing dodecanoic acid into the diet of growing animals appears to be the most efficient method for increasing the degree of saturation of body lipids without changing the concentrations of long-chain saturated fatty acids.

Comparative study of triacylglycerol fatty acids in milk from two Leporidae species: rabbit (Oryctolagus cuniculus) and hare (Lepus europaeus)

1. Fatty-acid composition of hare milk triacylglycerols markedly differed from that of rabbit milk and was essentially characterized by a 2.1 times lower concentration of medium-chain fatty-acids (M.C.F.A.). 2. Consequently, very high levels (greater than 70 moles %) of M.C.F.A., previously reported for rabbit milk, cannot be considered as a general characteristic of the Leporidae. 3. General tendencies recorded for intramolecular fatty acid distribution in hare milk triacylglycerols agreed with those reported for other animal species.

Specific distribution of fatty acids in the triglycerides of rainbow trout adipose tissue. Influence of temperature

In the trout, the unsaturated fatty acids are preferentially located in the beta-position and the saturated fatty acids in the alpha-position of triglycerides. This fatty acid distribution is retained even with diets containing lard. The fish are, therefore, able to modify completely the fatty acid distribution of dietary triglycerides. There is no retention of the beta-monoglyceride structure during the biosynthetic processes. However, the modification of the dietary fatty acid distribution by the trout seems to be more difficult at 18C than at 10C.