Changes in the concentration of some minor constituents of milk from cows fed low- or high-fat diets

• 1.1. The concentration of isocitrate and 2-oxoglutarate in cows' milk was determined in cows fed low- or high-fat diets.
• 2.2. The concentration of 2-oxoglutarate in milk correlated positively with the short and medium chain fatty acids in milk fat.
• 3.3. The concentration of isocitrate in milk correlated negatively with the short and medium chain fatty acids in milk fat.
• 4.4. It is proposed that changes in the concentrations of these minor constituents of milk occur as a result of changes in their intracellular concentrations. In the present experiment these changes are probably the result of changes in the rate of fatty acid synthesis de novo in the mammary gland.

     

Composition of milk of the pygmy sperm whale (Kogia breviceps)

• 1.1. A 315cm lactating female pygmy sperm whale, Kogia breviceps, accompanied by a 156cm female calf stranded on south Miami Beach, Dade County, Florida, on 13 March 1974, were used in the experiment.
• 2.2. A sample of milk from the lactating female contained less fat and more lactose than most cetecean milks previously analyzed.
• 3.3. Palmitic and oleic acids predominated in Kogia milk fat and long chain unsaturated fatty acids were lacking.
• 4.4. Kogia milk protein contained several unidentified constituents.
• 5.5. The chlorinated hydrocarbon residues in the milk were (ppb, wet weight): total DDT—1670; dieldrin—37; PCB—1203.

     

Influence of dietary sources of fat on lipid synthesis in mink (Mustela vison) mammary tissue

• 1.1. The fatty acid composition of the triglyceride fraction of mink milk sampled during mid-lactation (day 28 post partum) from two nursing mink was compared to that of plasma samples and to the fatty acid composition of the feed rations used.
• 2.2. Chemical analysis of the triglyceride composition of mink milk demonstrated only minute concentrations of fatty acids with a chain length below C₁₄.
• 3.3. The saturated C_16:0- and C_18:0-unit fatty acids in mink milk made up for 24–40% of the total amount of fatty acids extracted, the remainder being represented by mono and polyunsaturated long-chain (C₁₆-C₂₄) fatty acids.
• 4.4. Preliminary in vitro experiments proved the incorporation of¹⁴C-labelled glucose, acetate or palmitate into triacylglycerols in cultures of mink mammary tissue to be linear for at least 2 hr.
• 5.5. The in vitro capacity for de novo fatty acid synthesis in mink mammary tissue using 14C-labelled glucose or acetate was low, i.e. ranging from 0.096–0.109 nmol/g (fresh tissue)/min, and amounted to only about 5% of that obtained in the case of [¹⁴C]palmitic acid incubation.
• 6.6. Following ¹⁴C-labeIled acetic or palmitic acid incubation of mink mammary tissue neither desaturation nor chain elongation was observed.
• 7.7. In response to long-term feeding on rations with two different sources of animal fat (F = fish oil or L = lard) the influence of compositional changes in dietary neutral lipids on the fatty acid composition of the lipids of mink milk is discussed.

     

Modulation of mitochondrial ATPase sensitivity to inhibitors and stimulators by diet-induced changes in membrane lipid

• 1.1. Weanling rats were fed diets differing in fatty acid composition to determine if changes induced in cardiac mitochondrial membrane structural components alter the sensitivity of mitochondrial ATPase to inhibition by oligomycin and stimulation by 2,4-dinitrophenol.
• 2.2. Mitochondrial ATPase assayed in situ within the mitochondrial membrane isolated from animals fed diets higher in fatty acids of longer chain length, exhibited greater oligomycin sensitivity and lower 2,4-dinitrophenol-induced stimulation.
• 3.3. Concomitant diet-induced changes occur in the fatty acid, composition of phosphatidylcholine, phosphatidylethanolamine and cardiolipin, increasing overall length of fatty-acyl tails in the membrane phospholipids.
• 4.4. Diet fat mediated alterations in oligomycin sensitivity of mitochondrial ATPase and membrane fatty acid chain length suggest that _vivo changes in thickness of the lipid bilayer may alter mitochindrial ATPase functions.
• 5.5. The present study extends the concept that dietary fat affects mitochondrial membrane structure and function by demonstrating that the membrane-dependent sensitivity of mitochondrial ATPase to inhibitors and stimulators may be modulated by dietary fat.

     

Lipid digestion in cod (gadus morhua)

• 1.1. Cod, 2.6–3.4 kg. were fed a mixed diet of sprat, capelin oil and wheat flour.
• 2.2. Lipids from the feed, stomach and four intestinal segments were separated into tri-, di- and monoglycerides and free fatty acids and analysed by GLC.
• 3.3. All lipolytic products were concentrated in 14:0, 16:0 and 18:0, up to 60% and extremely low in the ω-3 fatty acids.
• 4.4. Residual triglycerides contained 80% of saturated and monoenoic fatty acids.
• 5.5. Linoleic acid increased from 2% in feed TG to 10% in TG of the rectum.

     

Fermentation and the production of volatile fatty acids in the alimentary tract of the rock hyrax,Procavia capensis

• 1.1. Aspects of ruminant-like metabolism were examined in the hyrax Procavia capensis.
• 2.2. High concentrations of volatile fatty acids occurred in the cardiac stomach with a predominance of acetic and lactic acids.
• 3.3. Acetic (69%), propionic (22%) and butyric (8%) acids occurred in highest concentrations in the proximal caecum, with appreciable amounts in the proximal colon, distal caecum and appendices.
• 4.4. The depot fat contained high proportions of unsaturated C₁₈ (linoleic and linolenic) acids.
• 5.5. The glucose level in the plasma was within the range established for non-ruminant herbivores.
• 6.6. The possibility of silage-like fermentation occurring in the cardiac stomach is discussed.

     

Differential effects of fatty acid chain length on the viability of two species of cactophilic Drosophila

• 1.1. Two columnar cacti in the Sonoran Desert, agria and organpipe, contain medium chain (C₈−C₁₂) fatty acids.
• 2.2. Necrotic tissues of these cacti serve as feeding and breeding substrates for Drosophila mojavensis but not D. nigrospiracula.
• 3.3. Results show that capric and lauric acids are the predominant fatty acids of both cacti.
• 4.4. Fatty acid chain length exhibits a differential effect on larval viability with caprylic acid (Q) having the greatest and myristic acid (C₁₄) having the least effect.
• 5.5. Drosophila mojavensis is more tolerant of free fatty acids than D. nigrospiracula, and this partly explains the ability of D. mojavensis to utilize agria and organpipe cacti.

     

The effects of oxalate and glucose on lipogenesis by isolated hepatocytes from normal and biotin-deficient chicks (Gallus domesticus)

• 1.1. Isolated hepatocytes synthesize fatty acids and cholesterol from lactate and acetate with lactate being the more effective substrate.
• 2.2. Biotin deficiency decreased fatty add synthesis from both substrates but stimulated cholesterogenesis.
• 3.3. Exposure of intact hepatocytes to oxalate inhibited fatty acid and cholesterol synthesis from lactate, this effect was enhanced in biotin-deficient chicks. A similar effect was not observed when acetate was the substrate.
• 4.4. Synthesis of fatty acids from lactate and acetate was stimulated by glucose, biotin deficiency increased this response. Cholesterogenesis was reduced in control but not biotin-deficient chicks.

     

Studies on the nutrition of the supralittoral isopod Ligia pallasii using chemically defined artificial diets: Assessment of vitamin,carbohydrate, fatty acid,cholesterol and mineral requirements

• 1.1. An artificial diet, consisting of a dry aggregate of 59 chemical substances, was used to assess the requirements of the sea slater Ligia pallasii for vitamins, carbohydrates, fatty acids, cholesterol and minerals.
• 2.2. Good growth and survival of L. pallasii was obtained on the diet, comparable to that on seaweeds and to that shown by a field population.
• 3.3. No dietary requirements for vitamins, fatty acids or cholesterol were shown for periods of 40 weeks or more for L. pallasii.
• 4.4. Carbohydrates were shown to be required by L. pallasii in its diet, in the order: starch, lactose > maltose, glucose > sucrose, cellulose.
• 5.5. Dietary requirements for minerals were, in order: calcium, magnesium, phosphorus > copper, nickel, zinc > iron, manganese, sulphur > iodine, silicon.
• 6.6. The results are discussed in relation to the role of gut bacteria in supplying required nutrients to their isopod hosts and the enhancement of this process through coprophagic behaviour.

     

A further contribution to the knowledge of the blood lipid fractions from the african elephant Loxodonta africana

• 1.1. Plasma lipids from 5 African elephants were extracted and fractionated into cholesterol esters, free fatty acids, triglycerides, phosphatidylcholine, phosphatidylethanolamine, phosphatidylinositol, sphingomyelin and glycosphingolipids. The fatty acids of various individual fractions were investigated by gas-chromatography.
• 2.2. All animals, except one, had a high linoleic acid content in cholesterol esters indicating an adequate supply of linoleic acid in the diet.
• 3.3. Phosphatidyl choline had a strong saturated character originating from the presence of unusually high quantities of stearic acid.
• 4.4. Phosphatidylethanolamine was present in small quantities and was characterized by a low content of arachidonic acid.
• 5.5. Sphingomyelin did not contain any long chain saturated acids. Instead it contained 10.2–47.0% of a long chain acid which was most likely monounsaturated.
• 6.6. The presence of significant quantities of glycosphingolipids was established.

     

Lipid changes in blood serum and tissues of the Egyptian Cobra “Naja haje haje” during the hibernation cycle

• 1.Total lipids, free fatty acids, triglycerides, phospholipids and total cholesterol in blood serum, liver, brain, cardiac and skeletal muscles of Naja haje haje were determined during the different phases of the hibernation cycle.
• 2.A sharp decrease in the level of total lipids of blood serum and all tissues occurred during hibernation. Upon arousal, lipogenesis is commonly restored.
• 3.Elevated concentrations of serum free fatty acids predominated in pre-hibernation and hibernation periods, while the tissues recorded highly significant declines during hibernation.
• 4.Occurrence of marked decreases in triglycerides contents of serum and tissues except the cardiac muscles in the hibernation and arousal phases.
• 5.Sharp increases in the phospholipid contents of blood and the selected tissues were recorded during hibernation. The level declined in both liver and cardiac muscles in arousing animals.
• 6.Total cholesterol level was lowered in blood during hibernation. The cardiac muscles showed a highly significant decrease while liver, brain and skeletal muscles showed elevations in the same phase.

     

The pathway of the biosynthesis of non-methylene-interrupted dienoic fatty acids in molluscs

• 1.1. The metabolic fate of 1-¹⁴C-acetate administered to the marine bivalve mollusc Mytilus edulis was investigated.
• 2.2. The active incorporation of the label in 20:2 non-methylene-interrupted dienoic (NMID) fatty acids was found.
• 3.3. Acetate incorporation patterns and specific radioactivity of mussel acids suggest that 22:2Δ7,13 and 22:2/gD7,15 arose by C₂ elongation of 20:2Δ5,11 and 20:2Δ5,13 respectively.
• 4.4. The proposed pathway of NMID fatty acid biosynthesis in molluscs is discussed.

     

Effect of different levels of dietary fats upon the positional distribution of fatty acids in rat body triacylglycerols

• 1.1. The main purpose of the study was to describe and to compare the effect of different dietary fatty acids introduced at different levels into the diet on the positional distribution of fatty acids in rat body triacylglycerols. Only distribution between sn-2 (internal) and sn-1 + sn-3 (external) positions was considered in this study.
• 2.2. The positional distribution of fatty acids was first determined for controls fed on a low fat diet (1% D.M.). The same study was then carried out with 11 different dietary treatments and results were systematically compared with controls. The effects of four main molecules were tested: linoleic acid, oleic acid, lauric acid and capric acid.
• 3.3. Different alterations of the positional distribution of fatty acids in body triacylglycerols were obtained. They are graphically described and discussed.

     

Changes in plasma glucose and lipid concentrations during treadmill exercise in domestic fowl

• 1.1. Plasma glucose, non-esterified fatty acid, triglyceride, cholesterol and lactate concentrations were measured during 90 min treadmill exercise at a work intensity of 55–60% maximum.
• 2.2. After 90 min exercise plasma glucose fell by 35% whilst the non-esterified fatty acid concentration rose to as much as 3–4 times resting.
• 3.3. Exercise had no significant effect on plasma cholesterol, triglyceride or lactate concentrations.
• 4.4. The findings indicate a progressive increase in fat utilization during prolonged exercise. Possible hormonal mechanisms underlying exercise-induced changes in lipid and carbohydrate metabolism are discussed.

     

Plasma membrane: Can its structure and function be modulated by dietary fat?

• 1.1. Compositional analysis of plasma membranes from rats fed nutritionally adequate diets different in fatty acid composition establishes that fundamentally different dietary fat intake results in alteration in structural lipid composition of plasma membranes in brain, liver and the intestinal mucosa.
• 2.2. Dietary differences in fatty acid intake altered the fatty acyl tail composition of plasma membrane phospholipids in brain, liver and intestinal mucosa.
• 3.3. Diet altered the phospholipid profile observed in brain synaptosomal and liver plasma membrane.
• 4.4. Feeding high vs low polyunsaturated to saturated fat diets for 7 days altered the fatty acid composition of phosphatidylcholine, phosphatidylethanolamine, sphingomyelin and mono-glucosylceramide isolated from plasma membrane of the intestinal mucosa

     

Digestive protease,lipase and amylase activities in stage i larvae of the american lobster,Homarus americanus

• 1.1. Digestive protease, lipase, and amylase of Stage I larvae of the American lobster Homarus americanus are characterized.
• 2.2. A sensitive method for detection of crustacean lipase was developed using an latroscan which combines thin-layer chromatography and flame ionization detection to quantify free fatty acids generated by lipase digestion.
• 3.3. pH optima of the three enzymes occurred at or near the pH of gastric fluid.
• 4.4. A time course study demonstrated slight increases in protease and amylase activities during the first larval stage, regardless of whether the lobsters were fed or not, whereas lipase activity was constant.

     

Cortical and medullary lipids of normal and nephrosclerotic human kidney

• 1.1. Major lipid classes from cortical and medullary zones of normal and nephrosclerotic human kidneys have been isolated and the fatty acid composition of each determined.
• 2.2. The nephrosclerotic tissue contained two times more total lipid than the normal kidney but, irrespective of kidney pathology, phospholipids were the major cortical lipids and neutral lipids were the predominant lipids in medullary zones.
• 3.3. Human kidney contained large amounts of phosphatidylcholines, phosphatidylethanolamines and sphingomyelins and although these were slightly increased in the sclerotic kidney, anatomical differences in phospholipid content were not significant.
• 4.4. Quantitative differences between the zones of normal kidney were found with triglycerides, diglycerides. free fatty acids and cholesterol; overall, the sclerotic tissue contained more triglycerides and small amounts of cholesterol esters with less significant regional differences.
• 5.5. Palmitic, oleic and stearic acid were the major fatty acids of neutral lipids; these plus linoleic acid were prevalent in phospholipids.

     

Comparative study of the endemic freshwater fauna of lake baikal—I. Phospholipid and fatty acid composition of two mollusc species,Baicalia oviformus and Benedictia baicalensis

• 1.1. Lipid and phospholipid compositions of endemic freshwater molluscs belonging to the class Gastropoda, Baicalia oviformus and Benedictia baicalensis, were studied.
• 2.2. The fatty acids composition of total lipids, neutral, glyco- and phospholipid fraction was investigated by capillary gas chromatography-mass spectrometry.
• 3.3. Ninety-five fatty acids were identified: 23 saturated (both iso- and anteiso-), 28 monoenoic, 14 dienoic and 30 polyenoic.
• 4.4. High percentage of the two main acids, 18:4 and 18:4(n-3) in phospholipid and glycolipid fractions were identified.
• 5.5. A number of unusual polyunsaturated fatty acids, such as 19:4, 18:5(n-3), 24:4(n-6), 24:5(n-6), 24:6(n-3), and furanoid acids, were found.

     

Fatty acid profile of the digestive gland and mantle in the bivalve Macoma balthica

• 1.1. Digestive gland and mantle fatty acids were studied in spring and summer in the bivalve Macoma balthica off the southern coast of Finland. The presence of lipids was also examined histochemically in various clam tissues.
• 2.2. the neutral lipid content of the digestive gland increased ca 4.5-fold during the annual growth period.
• 3.3. Neutral lipid fatty acids of the digestive gland, of which palmitoleic, eicosapentaenoic and palmitic acids were predominant, were clearly distinguished from phospho- and glycolipid fatty acids.
• 4.4. The degree of unsaturation of phospholipid fatty acids was higher in the cold season both in the digestive gland and mantle, mainly due to the titer of eicosapentaenoic acid.

     

Phospholipid and fatty acid composition of the freshwater sponge Euspongilla lacustris from the volga river estuary

• 1.1. Phospholipids of the freshwater sponge Euspongilla lacustris from the Volga river estuary were examined.
• 2.2. The freshwater sponges belonging to the family Spongillidae were shown to contain demospongic fatty acids.
• 3.3. Composition of fatty acids in phospho-, glyco- and neutral lipid fractions was studied.