Fatty Acid Feeding Research Articles

Milk fatty acid composition of dairy cows fed green whole-plant buckwheat, phacelia or chicory in their vegetative and reproductive stage

The hypothesis was tested that the phenological stage of dicotyledonous forages influences milk fatty acid (FA) composition of dairy cows. For this purpose buckwheat (Fagopyrum esculentum) and phacelia (Phacelia tanacetifolia; both in their first year of cultivation) as well as chicory (Cychorium intybus; second year) were cultivated in mixture with ryegrass (Lolium multiflorum). After 35 days of growth, feeding the green forages to 3×6 late lactating dairy cows at ad libitum access started. The realized dietary dry matter proportions of the test plants were (vegetative and reproductive stage): buckwheat, 0.60 and 0.55; chicory, 0.70 and 0.69; phacelia, 0.51 and 0.48. Experimental feeding lasted for 23, 17 and 26 days with buckwheat, chicory and phacelia, respectively. The complete diets additionally contained 2kg of concentrate and 1kg of barley straw per day per animal. Milk and feed samples were analyzed from every second day. Feedstuffs were analyzed for proximate contents, FA and fractions of phenolic compounds. In milk samples solids and FA were measured. Contents of FA and of phenol fractions decreased during advancing development stage in all test plants except total extractable phenols and total tannins in phacelia. This decrease was particularly pronounced for α-linolenic acid (ALA) and linoleic acid (LA) in buckwheat. Phenological stage had no influence on milk yield and gross composition, but ALA and LA proportions of milk fat declined with time in all groups. Proportions of ALA (14.2g/kg FA) and total poly-unsaturated FA in milk fat were highest with phacelia. Levels of conjugated linoleic acid (CLA) in milk fat were not affected by treatment or phenological stage. Vaccenic acid in milk fat was slightly elevated when feeding buckwheat and phacelia in the reproductive stage whereas it decreased with ongoing development in the chicory group. No systematic influence of phenological stage on the relative recovery of feed FA in milk fat occurred. The study did not confirm the hypothesis that the recovery rate of ALA would increase with maturing of the forages. In terms of generating a desired milk FA profile, phacelia and chicory seem however to be generally promising.

Incorporation of Omega‐3 Fatty Acids in Nile Tilapia (Oreochromis niloticus) Fed Chia (Salvia hispanica L.) Bran

AbstractThis study evaluated the effect of the inclusion of chia bran in the diet of Nile tilapia on the composition of n‐3 fatty acids (FA). Omega‐3 fatty acids provide health benefits such as reducing the risks of coronary heart disease, hypertension and inflammation, and the precursor alpha‐linolenic acid is considered strictly essential because it cannot be synthesized by humans, therefore must be ingested. Tilapias grown in tanks for a period of 45 days were treated with diets supplemented with either soybean oil (TI) or chia bran (TII). Proximal composition analysis of the feeds showed no significant difference. Feed FA quantification showed that the chia diet (TII) had a higher alpha‐linolenic acid (LNA) content. A significant increase was observed in the concentrations of LNA (8.38–81.31 mg 100 g−1 fillets), eicosapentaenoic acid (1.12–1.56 mg 100 g−1 fillets) and docosahexaenoic acid (19.55–26.55 mg 100 g−1 fillets) in tilapia fillets between 0 and 45 days for TII. Total lipids at 45 days under TII were fractionated into neutral lipids (67.66 %) and polar lipids (18.90 %). Thus, dietary supplementation with chia bran contributed to raising the nutritional quality of Nile tilapia fillets.

The effect of cyclooxygenase (COX) inhibitors on Japanese medaka (Oryzias latipes) reproduction parameters fed with high level of arachidonic acid (20:4 n-6)

Broodstock of mature Japanese medaka (Oryzias latipes Temminck and Schlegel, 1846) (mean weight 0.45 ± 0.03 g; age 6 months) were maintained in glass aquaria (8 males and 8 females in each aquarium). The fish were fed commercial feed (group C) or this feed was supplemented with arachidonic acid ARA (2 % of total fatty acids in feed; group A) and one of the COX inhibitors: resveratrol (group AR) or NS-398 (group ANS) with amount 20 mg kg−1 BW day−1 of one of the COX inhibitors. The effect of 2 weeks of feeding experimental diets on reproductive parameters (fecundity, embryo and larval survival, hatching rate, and larvae body weight) was analyzed. Larvae (obtained from experimental dietary treatments) were reared for 2 weeks. The percent of spawning female and fecundity was similar in dietary treatments. COX inhibitors in broodstock diet caused a decrease in embryo survival rate. Eggs of medaka from group ANS and AR revealed the lowest hatchability rate. In contrast, group A revealed a higher hatchability rate at the same time. Larval body weight after hatching was significantly the highest in this group. At the end of the experiment, larvae body weight ranged from 1.62 ± 0.43 mg in group AN to 2.89 ± 0.74 mg in group A. These results show that the COX inhibitors decreased gamete and larval quality regardless of high levels of ARA in broodstock diet.

Oil uptake by beef during pan frying: Impact on fatty acid composition

Fat entering food during frying needs to be monitored to control the nutritional properties of the products: fat penetration and fatty acid (FA) composition. The large difference between the apparent diffusion coefficients of lipids and meat fibers allows the use of diffusion-weighted magnetic resonance imaging (DWI) to measure oil uptake profiles. This method, in association with analysis of FAs by gas–liquid chromatography, predicts nutritional changes. Beef samples from finishing cows given control feed or high FA supplemented feed were fried in olive oil at 130°C and 180°C. Frying oil penetration was quantified by computing oil signal profiles from 3D DWI. Oil penetration was deeper at 180°C (5mm) than at 130°C (2.5mm), consistent with oil penetration processes. Oil penetration evaluated with DWI was correlated (R²=0.82) with biochemical analysis of FA composition. These results highlight the predominance of oil uptake over animal feed effects in the first millimeters of in-plane fried meat.

Stable Carbon Isotope Composition of c9,t11‐Conjugated Linoleic Acid in Cow's Milk as Related to Dietary Fatty Acids

This study explores the potential use of stable carbon isotope ratios (δ(13)C) of single fatty acids (FA) as tracers for the transformation of FA from diet to milk, with focus on the metabolic origin of c9,t11-18:2. For this purpose, dairy cows were fed diets based exclusively on C(3) and C(4) plants. The FA in milk and feed were fractionated by silver-ion thin-layer chromatography and analyzed for their δ(13)C values. Mean δ(13)C values of FA from C(3) milk were lower compared to those from C(4) milk (-30.1‰ vs. -24.9‰, respectively). In both groups the most negative δ(13)C values of all FA analyzed were measured for c9,t11-18:2 (C(3) milk=-37.0±2.7‰; C(4) milk -31.4±1.4‰). Compared to the dietary precursors 18:2n-6 and 18:3n-3, no significant (13)C-depletion was measured in t11-18:1. This suggests that the δ(13)C-change in c9,t11-18:2 did not originate from the microbial biohydrogenation in the rumen, but most probably from endogenous desaturation of t11-18:1. It appears that the natural δ(13)C differences in some dietary FA are at least partly preserved in milk FA. Therefore, carbon isotope analyses of individual FA could be useful for studying metabolic transformation processes in ruminants.

Technical note: Common analytical errors yielding inaccurate results during analysis of fatty acids in feed and digesta samples

The basic rules governing the proper fatty acid analysis of feed and digesta samples are sometimes overlooked, leading to potential errors in reporting the fatty acid content or composition of feed and digesta samples. The direct transesterification procedure of Sukhija and Palmquist (1988, J. Agric. Food Chem. 36:1202–1206) has become popular in analyzing fatty acids in feed and digesta samples obtained from animal feeding trials. One shortcoming of the Sukhija and Palmquist transesterification procedure is inaccurate analysis of fatty acids with conjugated double bonds. Digesta and milk samples from ruminant species typically contain a multitude of conjugated linoleic acid (CLA) isomers that easily undergo isomerization and epimerization following prolonged exposure to methanolic HCl. Modifications to the Sukhija and Palmquist procedure are given in this paper that allow successful determination of CLA isomers. Errors in fatty acid analysis also occur from misuse of internal standards; use of an internal standard is recommended in the Sukhija and Palmquist procedure as the preferred method to quantify total fatty acid content. The choice of internal standard may sometimes be important for obtaining accurate results. As an example, applying the direct transesterification procedure to a fat supplement high in saturated fatty acids yielded 613 mg/g of total fatty acids when C17 was used as the internal standard compared with 930 mg/g total fatty acids when C19 was used as the internal standard. Fatty acid content further increased to 952 mg/g when a unique unsaturated fatty acid (C13:1) was used as the internal standard.

Marinen-3 fatty acids promote size reduction of visceral adipose depots, without altering body weight and composition, in male Wistar rats fed a high-fat diet

We evaluated the effects of partly substituting lard with marine n-3 fatty acids (FA) on body composition and weight, adipose tissue distribution and gene expression in five adipose depots of male Wistar rats fed a high-fat diet. Rats were fed diets including lard (19.5 % lard) or n-3 FA (9.1 % lard and 10.4 % Triomar) for 7 weeks. Feed consumption and weight gain were similar, whereas plasma lipid concentrations were lower in the n-3 FA group. Magnetic resonance imaging revealed smaller visceral (mesenteric, perirenal and epididymal) adipose depots in the n-3 FA-fed animals (35, 44 and 32 % reductions, respectively). n-3 FA feeding increased mRNA expression of cytokines as well as chemokines in several adipose depots. Expression of Adipoq and Pparg was enhanced in the mesenteric adipose depots of the n-3 FA-fed rats, and fasting plasma insulin levels were lowered. Expression of the lipogenic enzymes Acaca and Fasn was increased in the visceral adipose depots, whereas Dgat1 was reduced in the perirenal and epididymal depots. Cpt2 mRNA expression was almost doubled in the mesenteric depot and liver. Carcass analyses showed similar body fat (%) in the two feeding groups, indicating that n-3 FA feeding led to redistribution of fat away from the visceral compartment.

A note on comparison of two extraction methods used to quantify C18 fatty acids in feed and digesta of ruminants

1. The effect of triterpenoid saponins from Saponaria officinalis on some blood hormones, metabolic parameters and fatty acid composition in dairy cows K. SZKUDELSKA, M. SZUMACHER-STRABEL, J. SZCZECHOWIAK, M. BRYSZAK, E. PERS-KAMCZYC, A. STOCHMAL, A. CIESLAK The Journal of Agricultural Science CrossRef

Dietary n-6- or n-3-rich vegetable fats and α-tocopheryl acetate: effects on fatty acid composition and stability of rabbit plasma, liver and meat

We supplemented diets with α-tocopheryl acetate (100 mg/kg) and replaced beef tallow (BT) in feeds with increasing doses of n-6- or n-3-rich vegetable fat sources (linseed and sunflower oil), and studied the effects on the fatty acid (FA) composition, the α-tocopherol (αT) content and the oxidative stability of rabbit plasma and liver. These effects were compared with those observed in a previous study in rabbit meat. As in meat, the content of saturated, monounsaturated and trans FA in plasma and liver mainly reflected feed FA profile, except stearic acid in liver, which increased as feeds contained higher doses of vegetable fat, which could be related to an inhibition of the activity of the stearoyl-CoA-desaturase. As linseed oil increased in feeds, the n-6/n-3 FA ratio was decreased in plasma and liver as a result of the incorporation of FA from diets and also, due to the different performance and selectivity of desaturase enzymes. However, an increase in the dose of vegetable fat in feeds led to a significant reduction in the αT content of plasma and liver, which was greater when the fat source was linseed oil. Increasing the dose of vegetable fat in feeds also led to an increase in the susceptibility to oxidation (lipid hydroperoxide (LHP) value) of rabbit plasma, liver and meat and on the thiobarbituric acid (TBA) values of meat. Although the dietary supplementation with α-tocopheryl acetate increased the αT content in plasma and liver, it did not modify significantly their TBA or LHP values. In meat however, both TBA and LHP values were reduced by the dietary supplementation with α-tocopheryl acetate. The plasma αT content reflected the αT content in tissues, and correlated negatively with tissue oxidability. From the studied diets, those containing 1.5% linseed oil plus 1.5% BT and 100 mg of α-tocopheryl acetate/kg most improved the FA composition and the oxidative stability of rabbit tissues.

Nutritional physiology during development of Senegalese sole ( Solea senegalensis)

The Senegalese sole, a species with a complex metamorphosis, difficulties in weaning and with occasional problems of malpigmentation and skeletal deformities, is a good model species to study larval nutritional physiology. In addition, the early metamorphosis and acquisition of a peculiar non-proactive bottom-feeding behaviour make early weaning an important issue in sole hatcheries. The present work reviews recent findings in different aspects of nutritional physiology during the development of Senegalese sole, in an attempt to optimize the composition of sole diets and to understand what are the limiting factors for weaning sole. Both digestive enzymes activity and tracer studies using 14C- Artemia show that sole larvae, even at young stages, have a high capacity for digesting live preys. This is reflected in a high growth potential and low mortality rates for this species during the larval stage compared to other marine fish species. Based on the observation of the digestive enzymes profile, early introduction of inert microdiets in co-feeding with Artemia does not seem to affect intestinal function. However, when co-feeding is not provided, intestinal activity may be depressed. Furthermore, early introduction of microdiets in co-feeding with Artemia may have a positive effect on survival rates, but at the expense of lower growth rates and higher size dispersal. This may reflect variation in the adaptation capacity of individual larvae to inert diets. High dietary neutral lipid (soybean oil) content results in reduced growth and accumulation of lipid droplets in the enterocytes and affects the capacity of Senegalese sole larvae to absorb and metabolise dietary fatty acids (FA) and amino acids (AA). Through tube feeding of different 14C-lipids and free FA it has been shown that FA absorption efficiency increases with unsaturation and that sole larvae spare DHA from catabolism. In addition, it was demonstrated that absorption efficiency varies according to molecular form, being highest for free FA, lowest for triacylglycerols and intermediate for phospholipids. Live preys commonly used in larviculture do not seem to have a balanced AA profile for sole larvae. Furthermore, the ideal dietary AA composition probably changes during development. Rotifers and Artemia metanauplii are apparently deficient in one or more of the following AA depending on the larval development stage: histidine, sulphur AA, lysine, aromatic AA, threonine and arginine. It has also been demonstrated that balancing the dietary AA profile with dipeptides in Artemia-fed larvae increases AA retention and reduces AA catabolism. When supplementing larval diets with limiting AA it should also be considered that sole larvae have different absorption, and retention efficiencies for individual AA, and that they have the capacity to spare indispensable AA. In addition, the absorption of free AA is faster and more efficient than that of complex proteins. Improvements in biochemical composition of inert microdiets for sole are likely to contribute to the reproducible weaning success of Senegalese sole.

The effects of early high omega‐3 fatty acid (FA) feeding on the growth in adult rats

Low birth-weight and premature delivery are associated with increases in mortality and morbidities. ω-3 FA have been shown to prolong the gestation period in humans. The long-term effects of perinatal ω-3 FA on growth has not been fully studied. In the present study, female Wistar rats were mated and fed one of three diets: control (CON, soybean oil, ω-3/ω-6 ratio ~ 0.14), high (HIGH, menhaden oil, ω-3/ω-6 ratio ~ 14.5) and low (LOW, safflower oil, ω-3/ω-6 ratio ~ 0). After delivery, litter size was culled to 8 pups. At day 21, pups were weaned and on day 24 all were put on a control diet. After weaning, a weight difference was noticed among the groups even though all were fed the same control diet. The HIGH group males gained weight at a significantly slower rate than the CON group until the age of 20 wks. The LOW group gained weight slower than CON group until 16 wks of age (weight at 19 wks: CON: 532 ± 36g; LOW: 521 ± 46; HIGH: 495 ± 42, p<0.01). All 3 male groups had similar food intake. The HIGH female pups did not catch up with the CON until 13 wks of age (BW at wk 12: CON: 255±17; LOW: 241±27; HIGH: 233±24, p<0.01). The HIGH females gained weight at a slower rate but consumed more food than other groups. These results show that perinatal high ω-3 FA feeding impaired growth in adult rats without affecting food intake. Catch-up growth is apparent in adulthood. Fetal programming may have played a role in these rats. Supported by a Gerber Foundation grant

N-3 fatty acids and chylomicron metabolism in the rat

Dietary n-3 fatty acids (FAs) reduce postprandial triacylglycerol concentrations in humans by unknown mechanisms. Our goals were to reproduce this phenomenon in the rat, and then to determine the mechanism. In an oral fat tolerance study two groups of rats were fed diets containing 2.1% ethyl esters of n-3 FA or olive oil for 2 weeks. After gavaging with emulsified soybean oil, the postprandial chylomicron triacylglycerol levels in the n-3 FA group were reduced by 40% (P < 0.05). The hypothesis that n-3 FA feeding reduced chylomicron production/secretion from the gut was tested by blocking chylomicron removal with Triton WR1339 before gavaging the rats with the fat load. This completely eliminated the hypochylomicronemic effect suggesting that chylomicron input was not inhibited by n-3 FAs. Chylomicron clearance was studied by injecting chylomicrons containing radioactive retinyl esters and triacylglycerol into rats from both groups. Pre-feeding with n-3 FAs accelerated the removal of chylomicron triacylglycerol and retinyl esters from the plasma with significantly lower fractions of dose remaining at 2, 4, and 8 min post-injection for both tracers. These findings suggest than n-3 FAs reduce postprandial chylomicronemia in the rat by accelerating chylomicron lipid clearance.

Carbohydrate-stimulated fatty acid synthesis de novo in human adipose tissue of different cellular types.

Abstract. Fatty acid (FA) synthesis in vitro by human adipose tissue has been determined as glucose incorporation into FA by slices and as the overall enzyme capacity for incorporation of acetyl units into FA from acetate and citrate by an optimal cytoplasmic assay system. Twelve subjects with normal, hypertrophic, hyperplastic or combined hypertrophic‐hyperplastic adipose tissue were examined during basal, weight stable conditions and after 3 and 22 days on a high‐carbohydrate low‐fat chemically defined diet (Vivasorb®) administered in amounts resulting in a moderately negative energy balance. Incorporations obtained with the cytoplasmic assay were several times higher than those with the whole cell technique. During carbohydrate feeding FA synthesis increased 3 and 11 times, respectively, as measured with the subcellular and the whole cell techniques. However, FA synthesis de novo was of little quantitative importance in human adipose tissue even during stimulated conditions. Expressed per g adipose tissue triglyceride (TG), there were no differences in FA synthesis between the four cellular groups before or during high‐carbohydrate feeding. Expressed per cell, large fat cells demonstrated a higher enzyme capacity for FA synthesis than did cells of normal size. The correlation between fat cell size and enzyme capacity for FA synthesis increased during the course of high‐carbohydrate feeding. During but not before high‐carbohydrate feeding there were several correlations between different whole cell and subcellular activities of adipose tissue and also strong correlations between FA synthesis in adipose tissue and serum TG. The latter correlation was most likely not related to a direct dependence between the two factors. Contrary to earlier reports, this investigation indicates the presence of ATP citrate lyase [E.C.4.1.3.8] in human adipose tissue and demonstrates that, in vitro, the enzyme capacity for citrate incorporation is at least as large as the capacity for acetate incorporation into FA if optima! conditions are used for both precursors.