Composition of fatty acids and triglycerides in human adipose tissue - Results from North-East Poland

The composition of fatty acids of human adipose tissue reflects the composition of fatty acids in diet [5, 7, 8, 10, 11]. It also depends to different extent on such factors as age [11, 13], sex [4, 11, 13], race [4, 13, 14], physical activity [18], physical condition (heart diseases) [14, 19] or adipose tissue kind [13]. Lack of data concerning the composition of fatty acids in adipose tissue of Poles made us undertake such studies. As there are no literature data available on triglyceride composition of human adipose tissue we decided to include this subject in our investigations.     

The structures of adipose tissue and heart muscle triglycerides in the domestic chicken (Gallus gallus)

Chicken (Gallus gallus) perineal, subcutaneous (leg), perinephric and pericardial adipose tissue and heart muscle triglycerides were subjected to stereospecific analysis. All were found to be asymmetric with a preponderance of saturated fatty acids in position 1 and a preponderance of unsaturated fatty acids in position 2. Position 1, for example, contained 48–55% saturated acids while position 2 contained 17–22% and position 3, 33–41%. Stereospecific analysis of fractions of the perineal triglycerides separated by argentation chromatography indicated that the proportions of the individual molecular species could be calculated assuming that there was 1-random, 2-random, 3-random arrangement of fatty acids in the triglycerides.     

Fatty acid composition and intramolecular structure of triglycerides from adipose tissue of the red deer and the reindeer

Rowett Research Institute, Bucksburn, Aberdeen, AB2 9SB Triglycerides extracted from perinephric, omental and subcutaneous adipose tissue of six female red deer and of two male and one female reindeer were analysed for the composition and intramolecular disposition of their component fatty acids. In their overall fatty acid composition, the triglycerides of normal and pregnant red deer were similar and resembled those of domesticated ruminants; trans-unsaturated acids were present and the perinephric triglycerides contained a relatively high proportion of stearic acid compared with triglycerides from other bodily sites. The triglycerides from corresponding adipose tissue of lactating hinds contained much less stearic acid and relatively more myristic, palmitic and palmitoleic acids, suggesting that fatty acids of exogenous origin were not being deposited because they were in demand for milk fat synthesis. The adipose tissue triglycerides of the reindeer were unusual in that they were, apparently, mainly of endogenous origin and showed a notable resemblance to the triglycerides of lambs reared on a virtually lipid-free diet. This was reflected in a comparatively low content of stearic acid in the perinephric triglycerides, and the absence of trans-unsaturated acids from all the triglycerides. Analysis of the principal feed (‘reindeer moss’, Cladonia) showed that, compared with normal herbage, it is a very poor source of exogenous fatty acids. Regardless of their fatty acid composition, the intramolecular structure of the triglycerides of the red deer and the reindeer conformed to the general distribution pattern common to most animals. Stearic acid was, for the most part, esterified to the primary alcoholic groups of the glycerol moiety (positions 1 and 3), as was palmitic acid, except when it was present in lower overall proportion than stearic acid. Unsaturated acids and the medium-chain acid, myristic acid, were mainly esterified to the secondary alcohol group (position 2).     

The effect of maternal linseed supplementation and/or lamb linseed supplementation on muscle and subcutaneous adipose tissue fatty acid composition of indoor lambs

Eighty eight lambs were used in a 2 × 2 factorial arrangement 1) to investigate the effect of maternal dietary linseed supplementation and/or lamb linseed supplemented concentrate on growth performance, carcass fat quality and fatty acid (FA) composition of muscle and dorsal adipose tissue of indoor lambs 2) to study the relationships between subcutaneous fat quality and FA composition. Feeding linseed to ewes increased C18:3 n-3 (ALA) proportion in milk and therefore the ALA supply to suckling lambs. However, ALA and n-3 polyunsaturated FA (n-3 PUFA) proportions in lamb tissues were not affected. Feeding linseed to lambs during the post-weaning period significantly increased the proportions of ALA and n-3 PUFA in tissues. Softer and more colored fat was associated with a decrease in even medium-chain saturated FA and increases in odd and methyl FA proportions but not with ALA proportion in subcutaneous adipose tissue.     

Composition of subcutaneous adipose tissue of dry-cured pork forelegs as affected by desalting and boiling: The effects of vacuum-packaging

The effects of desalting and boiling, with or without vacuum-packaging, on the composition of the subcutaneous adipose tissue of dry-cured pork forelegs were investigated. The adipose tissue contained 7.1% water and 91.0% lipids. The main fatty acids in glycerides (about 89% of total lipids) were oleic (39.6%), palmitic (23.9%), linoleic (13.7%) and stearic (12.6%) acids. The main fatty acids in free fatty acids (about 11% of total lipids) were oleic (36.0%), linoleic (28.4%) and palmitic (13.1%). The culinary treatment (desalting and boiling) caused significant decreases in dry matter and lipid contents. These decreases were not as great in vacuum-packaged samples because the lipid losses were prevented during the boiling stage. No significant changes in lipid fraction proportions (glycerides and free fatty acids) were observed. The samples boiled with vacuum-packaging showed higher contents of polyunsaturated fatty acids than did the samples boiled without vacuum-packaging.     

Refractometry of pork muscle and beef connective and adipose tissue

Bulk refractive index (RI) was measured with an Abbe refractometer using a red laser for transmittance (T) and a green laser for reflectance. The critical angle, although obscured by scattering, was detected subjectively at the red-green boundary. The refractometer also was operated under computer control, detecting RI photometrically. Pork longissimus thoracis (n=20) had higher RI than biceps femoris (1.357±0.004 versus 1.352±0.005, respectively, P<0.001). Longissimus thoracis also had lower Japanese pork colour scores (JPCS) than biceps femoris (2.92±0.37 versus 3.87±0.48, respectively, P<0.001). In pooled samples (n=40), RI was correlated with JPCS, r=-0.55, P<0.001. RI of bovine tendon (n=10) was higher than for adipose tissue (1.415±0.009 versus 1.343±0.001, P<0.001). Refraction may contribute to the inverse relationship between meat pH and paleness, and may affect signals from fibre-optic meat probes.     

Fatty acid composition of adipose depots of suckling lambs raised under different production systems

Forty-nine male Talaverana-breed suckling lambs slaughtered at 14 kg live weight were used to study the fatty acid composition of adipose depots of lambs raised under different management systems (pasture or drylot) and diets (maternal milk with or without a concentrate supplement). Drylot lambs displayed a higher fatness score, in addition to greater dorsal fat thickness; these parameters corresponded with a greater percentage of total fat at dissection. Addition of concentrate to the diet did not modify carcass fatness. Drylot lambs presented higher proportions of oleic acid (C18:1) and monounsaturated fatty acids (MUFA) and lower linolenic acid (C18:3) values in subcutaneous and intramuscular fat (muscle longissimus thoracis). The subcutaneous fat of these lambs thus displayed a higher n-6/n-3 PUFA ratio (C18:2/C18:3) than that of pasture-raised ones. Concentrate in the diet of both pasture and drylot lambs resulted in higher linoleic fatty acid (C18:2) and PUFA values and a greater PUFA/SFA ratio in intramuscular fat than the corresponding values of lambs which consumed maternal milk alone. Loin displayed a higher percentage of subcutaneous and intramuscular chemical fat than leg. Compared with intramuscular leg fat (muscle quadriceps femoris), intramuscular loin fat (muscle longissimus thoracis) had lower oleic acid (C18:1) and MUFA values, higher PUFA values and a higher PUFA/SFA ratio, due to greater linolenic acid (C18:3) levels.     

Composition and distribution of fatty acids in triglycerides from goat infant formulas with milk fat

Most infant formulas use vegetable oils in place of milk fat to provide an overall fatty acid profile similar to that of breast milk. Vegetable oils have 5 to 20% saturated fatty acids in the sn-2 position of triglycerides unless they are modified by interesterification. Interesterification is increasingly used for the fat for infant formulas to raise the level of saturated fatty acids in the sn-2 position to 40 to 60%. The objective of this study was to verify an alternative approach to providing the appropriate fatty acid profile, including in the sn-2 position, for a goat infant formula. In this method, 55% of total fat was made from goat milk fat and 45% from a mixture of unmodified high oleic sunflower, canola, and sunflower oils in a ratio of 44:30:26. The fatty acid profile was measured by gas-liquid chromatography and the relative percentage of fatty acids in the sn-2 position of triglycerides was measured via partial deacylation with Grignard reagent using trimethylsilyl derivatives of monoacylglycerols. Mixing goat milk fat with vegetable oils produced a formula with a profile of essential fatty acids and a ratio of linoleic:α-linolenic fatty acids within the required interval of 5 to 15:1 recommended for infant formula. The proportion of palmitic acid in the sn-2 position was 31%.     

Autofluorescence of adipose tissue measured with fibre optics

The optical absorbance and fluorescence of porcine subcutaneous adipose tissue were measured directly with fibre optics. Either mercury or xenon light sources were used to illuminate tissue samples through one branch of a bifurcated light guide. Fluorescence was detected through the other branch of the light guide. Grating, prism and continuous interference filter monochromators were installed at appropriate locations in the light path and measurements were made with a computer-operated photomultiplier whose dynamic range was optimized at each wavelength measured. There was a small absorbance peak at 420 nm. With excitation at 365 nm, the peak of the fluorescence emission spectrum was at 510 nm with a secondary plateau from 430 to 450 nm. Proline powder and purified biochemical Type III collagen were also autofluorescent with a peak emission at 510 nm. Adipose cells associated with bovine heart valves were examined by fluorescence microscopy to obtain preparations containing adipose cells plus all three histological types of connective tissue fibres on the same section. Reticular fibres (around adipose cells) together with collagen and elastin fibres (in the heart valves) were all autofluorescent. It is suggested that the major source of adipose tissue fluorescence is from the reticular fibres that surround adipose cells, with minor contributions from other sources such as collagenous septa, vascular elastin and, possibly, cytoplasmic components.     

Regulation of adipose tissue metabolism in support of lactation

In the dairy cow, adipose tissue lipid accumulates during pregnancy, and catabolism begins prior to parturition and increases dramatically afterward. After peak lactation, body lipid is replenished. The duration and magnitudes of these adaptations depend on milk energy secretion, net energy intake, genotype, and endocrine environment. Recent research efforts have focused on endocrine, genetic, and biochemical mechanisms underlying metabolic adaptations in cows of high production potential. Adipose tissue lipid synthesis is decreased and lipolysis is increased in early lactation. The magnitude and duration of these adaptations are increased in animals either consuming relatively less energy or producing more milk. Adipose tissue is more responsive to catecholamines in early and midlactation and in animals with higher production. This is more of an increase in maximal response than in sensitivity. In vivo and in vitro rates of adipose tissue lipolysis correlate positively with milk energy secretion, whereas lipid synthesis rates correlate with energy intake. Thus, mammary metabolic activity, within and among lactations, correlates with that in adipose tissue. Likely mechanisms include adaptations in receptors for homeostatic signals and modulation of postreceptor responses. Research is needed into neural, genetic, and hormone regulation of nutrient utilization and body fat use and recovery during lactation. Research should describe mechanistic relationships among nutrients in animals of high production as well as investigate cellular and molecular mechanisms suitable to genetic manipulation.     

类可可脂原料油中低熔点甘油三酯的组成、含量调控与综合利用

为了实现类可可脂在巧克力中更为高效的应用,降低其对产品品质的影响,综述了类可可脂原料油中低熔点甘油三酯的组成与熔化性质,概括了不同种类甘油三酯对巧克力霜变行为的作用特征;进一步讨论了控制低熔点甘油三酯含量的技术方法,包括基因工程和分提;最后,总结了经分提获得的低熔点成分的再利用。类可可脂原料油中低熔点甘油三酯可能对巧克力的制造(尤其是调温)和质量控制(如软化、起霜等)产生不利影响。通过分提选择性降低低熔点甘油三酯含量是制备高品质类可可脂的优选路径。     

Cholesterol content of muscle and adipose tissue from crossbred bulls and steers

Cholesterol content (mg/100g wet weight) of muscle and adipose tissue from crossbred bulls (N = 34) and steers (N = 35) was determined by spectrophotometry. Sampling site effects were highly significant, with subcutaneous adipose tissue (101·7) and perinephric adipose tissue (89·7) containing the most cholesterol, and longissimus muscle (58·3) containing the least. Semitendinosus and triceps brachii muscles were similar in cholesterol content (63·9 mg/100g and 63·7 mg/100g, respectively). Although sex condition differences within sampling sites were non-significant, steer carcasses may have more total cholesterol than bull carcasses because steers contain a higher percentage of fat than bulls raised under similar conditions.     

Influence of triglycerides and free fatty acids in milk replacers on calf performance, blood plasma, and adipose lipids

In a 4-wk study of 48 3-day-old calves we compared effects of feeding various fats or their free fatty acids in skim milk-powder based milk replacer, on calf performance, feed utilization, and blood plasma and adipose lipids. When fat was fed, calf performance and feed utilization were equivalent for tallow and coconut oil diets but markedly poorer for corn oil. Complete replacement (tallow) or one-half replacement (coconut and corn oils) of the fats with their free fatty acids reduced calf gains and feed efficiency. Tallow free fatty acids gave lower digestibilities of palmitic and stearic acid and reduced calcium absorption. Free fatty acids from both coconut and corn oils reduced diet palatability and intake; those from tallow and coconut oil markedly interfered (in vitro) with rennet clotting of milk replacers. The main lipid classes in blood plasma for all treatments were cholesteryl esters and phosphatidylcholine. High concentrations (56 to 87%) of linoleic acid occurred in cholesteryl esters for all diets despite low concentrations of linoleic acid in the tallow and coconut oil diets.     

Polychlorinated biphenyls (PCB) in human adipose tissue

This study describes the contamination of human adipose tissue with six selected polychlorinated biphenyls (PCB) known as "indicator congeners", with PCB no. 49 and the mixed inducer PCB nos. 156, 170, and 189. The low chlorinated biphenyls nos. 28, 49, and 52 could not be found in the tissue samples, while the average concentration of PCB no. 101 was 9.0 micrograms/kg. The content of PCB nos. 138, 153, and 180 was slightly below the values published by the "Deutsche Forschungsgemeinschaft" (DFG). The mixed inducer nos. 138, 156, 170, and 180 amounted to approximately 40% of all the PCBs measured. The PCB contamination was positively correlated with age: for the age group 61-70 years, with the exception of PCB no. 101, a distinct increase in the concentrations could be observed.     

Continuous low-dose infusion of tumor necrosis factor alpha in adipose tissue elevates adipose tissue interleukin 10 abundance and fails to alter metabolism in lactating dairy cows

Repeated bolus doses of tumor necrosis factor-α (TNFα) alters systemic metabolism in lactating cows, but whether chronic release of inflammatory cytokines from adipose tissue has similar effects is unclear. Late-lactation Holstein cows (n = 9–10/treatment) were used to evaluate the effects of continuous adipose tissue TNFα administration on glucose and fatty acid (FA) metabolism. Cows were blocked by feed intake and milk yield and randomly assigned within block to control or TNFα treatments. Treatments (4 mL of saline or 14 µg/kg of TNFα in 4 mL of saline) were infused continuously over 7 d via 2 osmotic pumps implanted in a subcutaneous adipose depot. Plasma, milk samples, milk yield, and feed intake data were collected daily, and plasma glucose turnover rate was measured on d 7. At the end of d 7, pumps were removed and liver and contralateral tail-head adipose biopsies were collected. Results were modeled with the fixed effect of treatment and the random effect of block. Treatment with TNFα increased plasma concentrations of the acute phase protein haptoglobin, but did not alter plasma TNFα, IL-4, IL-6, or IFN-γ concentrations, feed intake, or rectal temperature. Milk yield and composition were unchanged, and treatments did not alter the proportion of short- versus long-chain FA in milk on d 7. Treatments did not alter plasma free FA concentration, liver triglyceride content, or plasma glucose turnover rate. Surprisingly, TNFα infusion tended to decrease liver TNFα and IL-1 receptor 1 mRNA abundance and significantly increased adipose tissue IL-10 protein concentration. Continuous infusion of TNFα did not induce the metabolic responses previously observed following bolus doses delivered at the same rate per day. Metabolic homeostasis may have been protected by an adaptive anti-inflammatory response to control systemic inflammation.