Concentrations Of Individual Fatty Acids Research Articles

Exercise and training effects on ceramide metabolism in human skeletal muscle.

In rat skeletal muscle prolonged exercise affects the content and composition of ceramides, but in human skeletal muscle no data are available on this compound. Our aim was to examine the content of ceramide- and sphingomyelin fatty acids and neutral, Mg(2+)-dependent sphingomyelinase activity in skeletal muscle in untrained and trained subjects before and after prolonged exercise. Healthy male subjects were recruited into an untrained (n = 8, VO2,max 3.8 +/- 0.2 1 min1) and a trained (n = 8, Vo2,max 5.1 +/- 0.1 1 min2) group. Before and after a 3-h exercise bout (58 +/- 1% VO2,max) a muscle biopsy was excised from the vastus lateralis. Ceramide and sphingomyelin were isolated using thin-layer chromatography. The content of individual ceramide fatty acids and sphingomyelin fatty acids was measured by means of gas-liquid chromatography. The activity of neutral, Mg(2+)-dependent sphingomyelinase was measured using N-[14CH3]-sphingomyelin as a substrate. Prior to exercise, the muscle total ceramide fatty acid content in both groups was similar (201 +/- 18 and 197 +/- 9 nmol g(-1) in the untrained and trained group, respectively) and after exercise a 25% increase in the content was observed in each group. At rest, the muscle total sphingomyelin fatty acid content was higher in untrained than in trained subjects (456 +/- 10, 407 +/- 7 nmol g(-1), respectively; P < 0.05). After exercise a 20% increase (P < 0.05) in total sphingomyelin was observed only in the trained subjects. The muscle neutral, Mg(2+)-dependent sphingomyelinase activity was similar in the two groups at rest and a similar reduction was observed after exercise in both groups (untrained from 2.19 +/- 0.08 to 1.78 +/- 0.08 and trained from 2.31 +/- 0.12 to 1.80 +/- 0.09 nmol (mg protein) (-1) h(-1); P < 0.05 in each case). In conclusion, we have reported, for the first time, the values for ceramide fatty acid content and neutral, Mg2(+)-dependent sphingomyelinase activity in human skeletal muscle. The results indicate that acute prolonged exercise affects ceramide metabolism in human skeletal muscle both in untrained and in trained subjects and this may influence muscle cell adaptation and metabolism.

Restoration of the fatty acid composition of red seabream (Pagrus auratus) using a fish oil finishing diet after grow-out on plant oil based diets

This study evaluated the potential for manipulating the fatty acid composition of juvenile red seabream, Pagrus auratus. Prior to the start of the study, three groups of fish had been reared for 3 months on a fish oil based diet or diets where the added fish oil had been replaced with either canola or soybean oil. In the present study, fish that had previously been fed either the canola or soybean oil diets were fed a fish oil based diet. Three additional treatments included fish being maintained on their original diets of fish oil, canola oil or soybean oil. Fish were fed their respective diets twice daily to apparent satiety for 32 days. Samples of fish from each treatment were collected after 0, 1, 2, 4, 8, 16 and 32 days. Composition and growth of the fish were determined at each sample point. Most treatments showed no differences in growth performance, although fish fed a fish oil diet after previously being fed a soybean oil diet showed slightly better growth. No significant differences among treatments were observed in proximate composition of the fish, although there was a significant increase in total fat and individual fatty acid (g kg−1 live-weight) content of the fish from all treatments over the period of the study. No significant changes in the relative fatty acid composition (% of total fatty acids) over time were observed in the three treatments where fish were maintained on their original diets. In contrast, fish that were previously fed either the canola or soybean oil diets and were then fed a fish oil diet had significant changes in both the relative (% of total fatty acids) and absolute (g kg−1 live-weight) fatty acid content. Key changes observed included a decrease in the relative levels of polyunsaturated fatty acids (PUFA) such as 18 : 2n − 6 and 18 : 3n − 3. Increases in the relative levels of the long-chain polyunsaturated fatty acids (lcPUFA) 20 : 5n − 3 and 22 : 6n − 3 were also observed in both treatments. The rates of absolute (g kg−1 live-weight) change/accumulation of these fatty acids followed an exponential equation that differed for each fatty acid in each treatment. Examination of the retention efficiency of specific fatty acids also showed marked differences between fatty acids within treatments and also differences between treatments. Biologically important fatty acids such as 20 : 5n − 3 and 22 : 6n − 3 had only moderate retention efficiencies and these were unaffected by treatment. In contrast, the retention efficiencies of 18 : 2n − 6 and 18 : 3n − 3 suggested selective retention of these fatty acids when fed fish oil diets, but moderate catabolism when fed the plant oil diets. There were also high retention efficiencies of most saturated and monounsaturated fatty acids suggestive of active retention and/or active synthesis of these fatty acids by the fish. The results of this study, particularly the increases in lcPUFA, support the usefulness of a fish oil based finisher diet for fish raised predominantly on plant oil based diets.

Comparison of dietary fat and fatty acid intake estimated by the duplicate diet collection technique and estimated dietary records

A high saturated fatty acid intake is a well recognized risk factor for coronary heart disease development. More recently a high intake of n-6 polyunsaturated fatty acids (PUFA) in combination with a low intake of the long chain n-3 PUFA, eicosapentaenoic acid and docosahexaenoic acid has also been implicated as an important risk factor. To compare total dietary fat and fatty acid intake measured by chemical analysis of duplicate diets with nutritional database analysis of estimated dietary records, collected over the same 3-day study period. Total fat was analysed using soxhlet extraction and subsequently the individual fatty acid content of the diet was determined by gas chromatography. Estimated dietary records were analysed using a nutrient database which was supplemented with a selection of dishes commonly consumed by study participants. Bland & Altman statistical analysis demonstrated a lack of agreement between the two dietary assessment techniques for determining dietary fat and fatty acid intake. The lack of agreement observed between dietary evaluation techniques may be attributed to inadequacies in either or both assessment techniques. This study highlights the difficulties that may be encountered when attempting to accurately evaluate dietary fat intake among the population.

Fatty acids, total lipid, protein and ash contents of processed edible seaweeds

The total lipid, protein, ash and individual fatty acid contents of edible seaweeds that had been canned ( Saccorhiza polyschides and Himanthalia elongata) or dried ( H. elongata, Laminaria ochroleuca, Undaria pinnatifida, Palmaria sp. and Porphyra sp.) were determined (fatty acids by gas chromatography). Total lipid content ranged from 0.70±0.09 to 1.80±0.14 g/(100 g dry weight). The four most abundant fatty acids were C16:0, C18:1ω9, C20:4ω6 and C20:5ω3. Unsaturated fatty acids predominated in all the brown seaweeds studied, and saturated fatty acids in the red seaweeds, but both groups are balanced sources of ω3 and ω6 acids. Ash content ranged from 19.07±0.61 to 34.00±0.11 g/(100 g dry weight), and protein content from 5.46±0.16 to 24.11±1.03 g/(100 g dry weight). These protein, ash and ω3 and ω6 fatty acid contents show that processing (canning or drying) leaves these seaweeds with substantial nutritional value.

Variability of the fatty acids of the marine green algae belonging to the genus Codium

Analysis of fatty acids by gas chromatography-mass spectrometry (GC-MS) using serially coupled capillary columns with different polarity of stationary phases is reported. More than 40 volatile compounds, including, low molecular, dioic and fatty acids were determined of two marine green algae Codium dwarkense and C. taylorii. There are large variations in individual fatty acid contents according to species, season and location of the genus Codium. Statistical analysis of variability of fatty acids belonging to the genus Codium is reported.

Cholesterol changes the fatty acid composition of rat enterocytes.

The effect of free cholesterol on the fatty acid composition and growth of rat fetal enterocytes was investigated in the absence and presence of 10% (v/v) fetal calf serum. Cholesterol caused a significant reduction of cell number after 6 and 12 h in culture. The fatty acid composition of enterocytes cultured in the presence of serum was also changed by the presence of 20 microM cholesterol. The fatty acid profile was determined by HPLC using fluorescence detection (325 nm excitation and 395 nm emission). Cholesterol (20 microM) increased the proportion (given in percentage of the total fatty acids) of the following fatty acids in cultured cells: lauric (by 42%), oleic (by 34%), linoleic (by 44%) and gamma-linolenic (by 20%) acids and reduced the proportion of palmitic (by 12%), stearic (by 20%), arachidonic (by 21%) and docosahexaenoic (by 44%) acids. In addition to modifying the content of individual fatty acids, cholesterol increased the polyunsaturated/saturated fatty acid ratio from 0.48 to 0.67 and the unsaturation index from 67.12 to 75.30. This is the first evidence that cholesterol modifies fatty acid composition possibly via de novo fatty acid synthesis and desaturation.

Biomarkers and the measurement of fatty acids.

To review the various biomarkers of dietary intakes of fatty adds in human populations, their measurement, limitations and analytical considerations. Review of the literature. Although there is no good biomarker of intake of total fat, a number of alternatives exist for assessing the intakes of exogenously produced fatty acids that are consumed. Adipose tissue, erythrocyte membrane concentrations and serum or plasma levels can reflect prior intakes over the past few hours to the past few years. The concentrations of individual fatty acids in these media generally reflect relative levels, and are influenced by a number of factors. Although relatively expensive to analyse, a single analysis by gas chromatography or high-performance liquid chromatography provides information on multiple fatty acids, and is superior to attempting to measure specific fatty acids using traditional dietary assessment methods. Biomarkers of fatty acids that reflect long-term intake are available for nutritional epidemiology purposes. Analytical methods have become very accurate and able to detect and quantify smaller families, such as trans-fatty acids.

Comparison of fatty acid composition of domestic and imported margarines and frying fats in Bulgaria

A total of 82 dietary fats sold on the Bulgarian market in the period 1995-2000 were analyzed. The samples included 68 table margarines (50 of which were imported), 10 frying fats (6 imported) and 4 salad dressings (all imported). A validated analytical method, thin-layer chromatography-AgNO 3 -densitometry, was used. It enabled direct determination of all fatty acid groups, differing by degree of unsaturation and double bonds geometry. Low levels of trans fatty acids (TFA) down to 0.1% of the total for mono trans-trienoic (Tcct) and mono trans-dienoic (Dct), and down to 0.2% for transmonoenoic (Mt) were quantitated, with an error under 3% and a standard deviation of 0.1-1.5. The total content of TFA in table margarines varied from 0 to 26.9% with a mean value of 8.6 ± 7.2% for imported and 1.6 ± 3.4% for Bulgarian samples. Saturated fatty acids (SFA) content varied from 11.5 to 45.7%, with a mean value of 25.4 ± 5.7% for imported and 26.9 ± 5.2% for Bulgarian margarines. A general trend of lower levels of TFA and SFA in imported margarines was observed over the studied period. Additionally, the content of individual saturated fatty acids was determined by gasliquid chromatography in 37 of all studied samples.

Ceramides and sphingomyelins in skeletal muscles of the rat: content and composition. Effect of prolonged exercise.

The sphingomyelin-signaling pathway has been described in many tissues. Ceramide is the main second messenger in this pathway. Ceramide has also been shown to be present in skeletal muscles; however, there are few data on the regulation of the content of ceramide in muscle tissue. Moreover, there are no data on the content of particular ceramides or their composition in the muscles. The aim of the present study was to examine the content and composition of fatty acids (FA) in ceramide and sphingomyelin moieties and the activity of neutral Mg(2+)-dependent sphingomyelinase in different skeletal muscle types of the rat at rest and after exhausting exercise of moderate intensity. The experiments were carried out on male Wistar rats, divided into two groups: 1) control and 2) exercised until exhaustion on a treadmill. Soleus and red and white gastrocnemius muscles were taken. Ceramide and sphingomyelin were separated by TLC. The content of individual FA in the two compounds was determined by gas-liquid chromatography. Twelve different ceramides and sphingomyelins were identified and quantified in each muscle type according to the FA residues. Saturated FA consisted of 68, 67, and 66% of total ceramide-FA and 75, 77, and 78% of total sphingomyelin-FA in soleus and red and white gastrocnemius, respectively. The total content of ceramide- and sphingomyelin-FA and the activity of sphingomyelinase were highest in the soleus and lowest in the white gastrocnemius. Exercise resulted in a reduction in the total content of ceramide- and sphingomyelin-FA in each muscle. This was accounted for mostly by a reduction in content in the amount of saturated FA. Exercise reduced the activity of neutral Mg(2+)-dependent sphingomyelinase in the soleus and red gastrocnemius and did not affect its activity in the white gastrocnemius. We conclude that the sphingomyelin-signaling pathway is present in skeletal muscles and that it is influenced by prolonged exercise.

Correlation studies on oil content and fatty acid profile of some Cruciferous species

Mean individual fatty acid concentration among differentspecies of the family Cruciferae are not similar because of the presence ofdifferent kind of significant relationship among the individual fatty acids.Brassica napus L., Sinapis alba L.,Raphanus caudatus L.f. Raphanus sativusL. and B. nigra (L.) Koch arecomparatively low erucic acid (<40%) containing species. Crambeabyssinica Hochst. ex. R. E. Fries collections gave as high as 60%erucic acid. Low erucic acid concentration was found associated with thepresence of high level of palmitic and oleic acid concentrations. Erucic acidconcentrations were found varied within the range of 42 to 57% among thecollections of Brassica rapa L. and B.carinata A. Braun. All the collections ofB. nigra (L.) Koch were found to havehigher proportion of linoleic acid than the corresponding oleic acidconcentration. Linolenic acid concentrations of B.nigra (L.) Koch was also higher in comparison to otherspecies of the Cruciferae. Raphanus collections were foundto contain higher levels of total saturated fatty acids as well as eicosenoicacid. Oil content of the total collections under present study did not show anysignificant relationship either with linolenic acid or with erucic acidconcentration. But significant positive relationship was observed between totaloil and erucic acid level within the collections of B.juncea Czern. & Coss. Similarly significant negativecorrelation was observed between total oil and linolenic acid content inBrassica rapa L. ssp. trilocularis (Roxb.) Hanelt, yellow sarson.

Effect of N fertilisation rate, energy supplementation and supplementation strategy on efficiency of N utilisation in the sheep rumen

The effect of nitrogen (N) fertilisation (200 vs. 400 kg N ha‐1 year‐1) of pasture cut in the beginning (end of May) and the end (end of August) of the grazing season and of simultaneous or separated feeding of maize and grass (400 kg N ha‐1 year‐1) on efficiency of N utilisation in the rumen has been studied using four rumen canulated wethers. Doubling N fertiliser rate increased grass CP production by about 60%, but induced extensive excess of rumen degradable N, reflected in high urinary urea excretion (rpearson = 0.747). The latter was lower (74% at the maximum) when feeding less fertilised or older grass or when supplementing with maize silage. Although simultaneous feeding of maize silage with grass changed patterns of rumen ammonia concentrations, no change in urinary excretion of purine derivatives was observed. Hence, faecal or urinary N excretion was unaffected by the supplementation strategy. Microbial growth efficiency was estimated from urinary excretion of purine derivatives and fermented OM. The latter was calculated from total rumen CH4 production, based on rumen fermentation stoichiometry and taking into account proportional concentrations of individual volatile fatty acids. Higher levels of intake tended to improve rumen microbial growth efficiency slightly (rpearson=0.406), which, however, could not compensate for the reduced effective rumen DM degradability (rpearson =‐0.442). The latter was apparently associated with a partial shift of the fermentation from the rumen to the hindgut, as suggested from the negative correlation (rprarson =‐0.745) between faecal RNA concentrations and rumen effective degradability.

Plasma non‐esterified fatty acid profiles and 17β‐oestradiol levels of juvenile immature and maturing adult American eels in the St Lawrence River

American eels Anguilla rostrata, collected from three distinct locations along the St Lawrence River (Lake St Lawrence, Quebec City and Kamouraska), were thought to consist entirely of out‐migrating adults at Quebec City and Kamouraska and of both resident and migrants at Lake St Lawrence. The mean plasma levels of 17β‐oestradiol closely paralleled the trend observed with gonadosomatic index (IG) and oocyte development. The highest levels of 17βoestradiol and IG were observed in Quebec City and Kamouraska, while the levels observed in the resident eels from Lake St Lawrence were very low. Generally, the concentration of total plasma non‐esterified fatty acids (NEFA) appeared to follow the trend of 17β‐oestradiol and IG and increased with sexual maturity. However, the most sexually mature group, eels from Kamouraska, had the lowest total plasma NEFA levels. The reason for the drop is not clear at present. In addition, a number of shifts in the plasma NEFA profiles of American eels did occur during their migration in a downstream direction, with several fatty acids either increasing or decreasing in relative abundance. The ratio of n3: n6 fatty acids declined with increasing sexual maturity as most n3 fatty acids became less abundant. Although the correlation between gonadal development and the relative concentration of individual fatty acids was not always clear, both arachidonic acid (20: 4n6) and docosahexaenoic acid (22: 6n3) were significantly higher in the plasma of out‐migrating adults than in resident yellow phase eels.

Changes in Higher Fatty Acids and Related Biochemical Characteristics of Flue-cured Tobacco during Aging

Abstract The purpose of this study was to investigate the changes in higher fatty acids and related biochemical characteristics of flue-cured tobacco during the process of aging. The concentration of total lipids in flue-cured tobacco decreased gradually during natural aging, but the concentration of individual principal higher fatty acids in flue-cured tobacco changed much differently during aging. Myristic acid (C14:0) increased constantly during the whole aging process. Stearic acid (C18:0) and oleic acid (C18:1) increased at the initial stages of aging and reached maximum contents after one year of aging, but decreased thereafter. Palmitic acid (C16:0), linoleic acid (C18:2), and linolenic acid (C18:3) decreased constantly throughout aging, especially the linolenic acid content which decreased drastically. Furthermore, the ratio of unsaturated fatty acids (C18:1; C18:2; C18:3) and saturated fatty acids (C14:0; C16:0; C18:0) decreased continuously during aging, from 1.00 at the initial stage to 0.43 at the end of aging, when it seemed to be stabilized. The maximum rate of decrease of the ratio was between 12 to 18 mo during aging. The activity of lipoxygenase (LOX) and peroxidation value (POV) initially increased and reached their highest levels after 6 mo of aging, but steadily decreased thereafter. The acid value (AV) and malondialdehyde (MDA) content increased during the first 12 mo of aging, then decreased rapidly after 12 and 18 mo, respectively.

Variability of the fatty acid composition during development of the green microalga Apatococcus constipatus.

The green microalga Apatococcus constipatus was investigated for its fatty acid composition using GC and MS techniques. Considerable variations were found in individual fatty acid contents according to the stage of culture development. A set of saturated fatty acid homologues was distinguished as the main component regardless of the culture age. The occurrence of some uncommon fatty acids in minor amounts, such as hydroxylated ones, was found to be characteristic of the studied species. Depending on the development stage, those compounds were detected either only during initial growth phases or throughout the cultivation time.

Intake and rumen degradation in cattle fed napier grass (&lt;I&gt;Pennisetum purpureum&lt;/I&gt;) supplemented with various levels of &lt;I&gt;Desmodium intortum &lt;/I&gt;and &lt;I&gt;Ipomoea batatus&lt;/I&gt; vines

This study was conducted to assess the effect of greenleaf desmodium (Desmodium intortum) and sweet potato vine (Ipomoea batatus) supplementation of napier grass on dry matter intake, degradation and rumen fermentation in Friesian steers. Four fistulated steers were offered napier grass diets containing 0, 10, 20 or 30% desmodium or sweet potato vine in two 4 x 4 latin squares. Organic matter intake per kg metabolic body weight increased linearly with increasing inclusion level of desmodium (74-90 g/kg 0.75) and sweet potato vine (78-94 g/kg 0.75). Crude protein intake also increased linearly with the increase in inclusion level of desmodium (7.6-13.0 g/kg 0.75) and sweet potato vine (7.9-12.9 g/kg 0.75). Supplementation improved DM degradation but did not change rumen pH. Rumen fermentable organic matter increased by up to 52% and 43% for desmodium and sweet potato vine respectively at the highest levels of supplementation. Ammonia nitrogen concentrations increased with increasing level of desmodium (130-214 mg/l) and sweet potato vine 139-235 mg/l). Inclusion of desmodium and sweet potato vine led to small increases in concentrations of total and individual volatile fatty acids. It was concluded that the two forage supplements could play an important role in improving animal performance when napier grass is fed as the basal diet. South African Journal of Animal Science, Vol 31, Issue 3, Oct – Dec (2001): p.149-157 Key Words Napier, Desmodium, Sweet potato vine, Intake, Degradation, Fermentation, Rumen, Nutrition, Cattle

Fatty and Amino Acids Composition of Melon (Cucumis melo Var. saccharinus) Seeds

Seeds obtained from melon (Cucumis melo var. saccharinus Naud, cv. Daimiel commercially classified as “Pele de Sapo”) were analyzed for their proximate composition. The seeds contained high percentage of lipids (32.3%) and proteins (19.3%). Freshly extracted oil presented acid and peroxide values of 1.76 and 4.02, respectively. The iodine and saponification values were 109.6 and 191.4, respectively. Gas chromatographic analysis of the oil revealed the presence of 23 fatty acids varying from C-6 to C-24 with the exception of C-11, C-19, C-21 and C-23. The concentrations of individual fatty acids varied from trace (less than 0.06%) quantities to about 51%. Linoleic, oleic, palmitic, and stearic acids were the principal fatty acids contributing to 51, 31, 8.5 and 6.1%, respectively, of the total fatty acids which had a relatively high percentage (82.76%) of unsaturated fatty acids. Seed proteins were deficient in the essential amino acids methionine, lysine, threonine and valine. Methionine and lysine were the first and second limiting amino acids, while arginine, aspartic and glutamic acids (13.4, 8.9 and 19.7 g/100 g of proteins, respectively), were present in good quantities.

Changes in composition and quality of sunflower oils during extraction and degumming

The influence of different stages of processing on composition and quality of crude sunflower oil was studied through the determination of fatty acids, metal and phosphorus contents, free fatty acids, peroxide and anisidine values, tocopherols, polar compounds, waxes and oxidative stability. No significant changes in the content of individual fatty acids and tocopherols were observed during processing. The composition of some minor constituents as metals, waxes and phospholipids was strongly affected by the extraction and water degumming processes. Sunflower oils obtained by hexane extraction presented a higher initial deterioration but also a higher oxidative stability than oils obtained by pressing.

Fatty acid chain length and degree of unsaturation are inversely associated with serum triglycerides.

Little is known about the association between dietary fatty acids and serum triglycericle concentrations. Plasma fatty acids may reflect dietary intake and can be used to study the relationship between concentrations of individual fatty acids and serum lipids. We examined the cross-sectional relationship of plasma fatty acids with serum nonfasting triglyceride and total cholesterol concentrations. Relative concentrations of individual plasma phospholipid fatty acids were determined by gas liquid chromatography among 4,158 men aged 40-42 yr, who participated in a population study. The pattern of associations between individual fatty acids and cholesterol was different from that between individual fatty acids and triglyceride concentrations. All fatty acids displayed positive associations with total cholesterol concentration except linoleic acid, which was inversely related to cholesterol. In contrast, associations between individual fatty acids and triglyceride concentrations differed in strength and direction depending on both carbon chain length and the degree of unsaturation. Concentrations of very long chain (20 carbon atoms or more) saturated, monounsaturated, and n-3 polyunsaturated fatty acids showed significant inverse associations with triglycerides, whereas shorter fatty acids within these classes were positively associated with triglyceride concentrations. The present data suggest that the associations between concentrations of serum triglycerides and plasma phospholipid fatty acids depend on both fatty acid chain length and the degree of unsaturation.

A comparative study of nutrient digestibility, kinetics of degradation and passage and rumen fermentation pattern in goats and sheep offered good quality diets

The in vivo digestibility, the rates of fermentation and passage and the rumen fermentation pattern were compared in Granadina goats and Segureña wethers fed alfalfa hay (AH), alfalfa hay/sugar beet pulp, 4:1 (AH/SB) and alfalfa hay/sugar beet pulp/oat grain, 3:1:1 (AH/SB/OG) at approximately maintenance level. The animals were at stall and no selectivity was practised. The nylon bag technique was used to estimate the extent and fractional rate of degradation of the feed in the rumen. The fractional outflow rate of particles was determined with chromium as a marker. No significant interspecies differences in the nutrients digestibility were found. Values of potential and effective degradability and rates of degradation of both dry matter and protein were similar in goats and sheep. Also, the calculated values of the fractional rate of passage of the digesta out of the rumen were not significantly different between animal species. Ammonia-N concentrations were higher in the rumen liquor of goats than in sheep. No clear trend in the concentration of total and individual volatile fatty acids was observed when comparing goats and sheep with the exception of an increased proportion of valeric acid in the rumen liquor of sheep. From present and previous trials it is concluded that goats and sheep show equal capacities of digestion of medium to good quality diets when fed at energy maintenance level and feed selection is absent. This would validate extrapolations of feed evaluations, what implies a unique energy value.

Characterisation of some nutritional constituents of melon ( Cucumis melo hybrid AF-522) seeds

Seeds from a melon hybrid AF-522 largely cultivated in the northeast region of Brazil were analysed for their proximate composition. The seeds contained high percentages of lipids (30.8%) and proteins (14.9%). Hexane-extracted oil had acid, peroxide, iodine and saponification values of 2.06, 4.96, 111.8 and 210.6, respectively. Gas chromatographic analysis of the oil revealed the presence of 24 fatty acids varying from C 6 to C 24 with the exception of C 11, C 19, C 21 and C 23. The concentrations of individual fatty acids varied from trace quantities to about 64%. Linoleic, oleic, palmitic and stearic acids were the principal fatty acids contributing to 64.1, 19.4, 9.5 and 4.9%, respectively, of the total fatty acids which had a relatively high percentage (84.4%) of unsaturated fatty acids. Seed proteins were rich in arginine, aspartic and glutamic acids while limiting amino acids were methionine and lysine.