Feeding Flaxseed Research Articles

EFFECT OF POMEGRANATE PEEL ADDITION TO THE DIET ENRICHED WITH LINSEED OIL ON PERFORMANCE, LIPID TRAITS IN THE MEAT, BLOOD LIPID PROFILE AND ANTIOXIDANT PROPERTY OF RABBITS UNDER SUMMER CONDITIONS

The present work aimed to investigate the growth performance, meat omega-3 (n-3) and omega 6 (n-6) fatty acids, immunological responses, lipid peroxide and the antioxidative status resulting from supplemented linseed oil diets of growing V-line rabbits with two levels of pomegranate peel (POM) during summer season from June to August. Forty-eight growing V-line rabbits of both sexes, 7 weeks old, with initial weight of 982.75 ± 15.85 g were used in the present experiment. Rabbits were randomly distributed to four groups of 12 rabbits each. Each group was further sub-divided into 4 replicates of 3 rabbits. Group 1 fed a pelleted basal diet with standard components and served as control group, group 2 fed a pelleted diet with 2% linseed oil, group 3 fed a pelleted diet containing 2% linseed oil with 0.75 % POM, group 4 fed a pelleted diet containing 2% linseed oil with 1.5 % POM. The obtained results showed that the different treatments had insignificant effect on final body weight and daily body weight gain, however, significant (P≤0.05) decrease in feed intake and significant (P≤0.05) improvement in feed conversion were recorded in comparison with the control. Results for pre-slaughter weight, percentage of hot carcass and liver were insignificantly affected by different treatments in comparison with control. The different treatments showed significant decrease in the abdominal fat and the muscle total cholesterol in comparison with the control group. The n-3 fatty acids were significantly (P≤0.05) increased by feeding linseed oil, linseed oil plus pomegranate peel, while the n-6 fatty acids were decreased significantly by feeding linseed oil and linseed oil plus pomegranate peel in comparison with control. Hematological parameters and antibody titers against sheep red blood cells (SRBCs) were insignificantly affected by different treatments. While, specific IgG was significantly improved in all experimental groups compared with control. Serum total lipids, low density lipoprotein and malondialdehyde (MDA) were significantly (P ≤ 0.05) decreased due to different experimental diets in comparison with the control group. Total cholesterol was decreased but triglycerides were increased in animals received linseed oil in their diet in comparison with control. High density lipoprotein concentration, HDL/LDL ratio and total antioxidant capacity were significantly (P ≤ 0.05) increased by different experimental treatments as compared with the control group, with one exception that TAC was insignificantly increased than in control by receiving linseed oil in the diet. It is concluded that dietary supplementation of linseed oil plus POM in growing rabbit’s diets had a beneficial effect on the composition of the meat lipid fraction by increasing the concentration of n-3 fatty acids and improving the feed conversion, blood serum lipid profile and antioxidant status.

Effects of Feeding Flaxseed Oil (Linum usitatissimum) on Brain Edema and Blood Fat Levels in the Rat Stroke Model

Effects of Feeding Flaxseed Oil (Linum usitatissimum) on Brain Edema and Blood Fat Levels in the Rat Stroke Model

Effects of enriching goat meat with n − 3 polyunsaturated fatty acids on meat quality and stability

The effect of enriching goat meat with n−3 polyunsaturated fatty acids (PUFA) on meat quality, sensory evaluation, and lipid oxidative stability at different postmortem aging times was investigated. Samples from longissimus thoracis muscle of Boer bucks (n=24) fed diets containing 0% (control, L0), 10% (L10), or 20% (L20) whole linseed were collected for analysis. For meat quality and oxidative stability, sub samples were subjected to 1-day or 7-day postmortem aging period. Feeding linseed had successfully increased n−3 PUFA in goat meat. The increments in 18:3 n−3 were 682% and 975% for L10 and L20, respectively, compared to L0. The increments in total n−3 PUFA were 444% and 590%for L10 and L20, respectively, compared with L0. There was no effect on cooking loss, shear force and color at 1-day aging time. However, at 7-day of aging time the color was affected. Subjectively, the tenderness, juiciness and overall acceptability of L20 meat were rated better than those of L0 and L10. However, no differences were detected in color, flavor, and aroma attributes from sensory evaluation. Lipid oxidation was increased with increasing the contents of n−3 PUFA and postmortem aging time.

Muscle antioxidant (vitamin E) and major fatty acid groups, lipid oxidation and retail colour of meat from lambs fed a roughage based diet with flaxseed or algae

The effect of feeding flaxseed or algae supplements to lambs on muscle antioxidant potential (vitamin E), major fatty acid groups, lipid oxidation and retail colour was investigated. Lambs (n=120) were randomly allocated to one of 4 dietary treatments according to liveweight and fed the following diets for eight weeks: Annual ryegrass hay [60%]+subterranean clover hay [40%] pellets=Basal diet; Basal diet with flaxseed (10.7%)=Flax; Basal diet with algae (1.8%)=Algae; Basal diet with flaxseed (10.7%) and algae (1.8%)=FlaxAlgae. Flaxseed or algae supplementation significantly affected major fatty acid groups in muscle. The addition of algae (average of Algae and FlaxAlgae) resulted in lower vitamin E concentration in muscle (P<0.003; 1.0 vs 1.3mg/kg of muscle) compared with lambs fed a diet without algae (average of Basal and Flax). Increasing muscle EPA+DHA by algae supplementation significantly increased lipid oxidation, but retail display colour of fresh meat was not affected.

Milk Yield, Composition, and Fatty Acid Profile in Dairy Cows Fed a High-concentrate Diet Blended with Oil Mixtures Rich in Polyunsaturated Fatty Acids.

To evaluate the effects of feeding linseed oil or/and sunflower oil mixed with fish oil on milk yield, milk composition and fatty acid (FA) profiles of dairy cows fed a high-concentrate diet, 24 crossbred primiparous lactating dairy cows in early lactation were assigned to a completely randomized design experiment. All cows were fed a high-concentrate basal diet and 0.38 kg dry matter (DM) molasses per day. Treatments were composed of a basal diet without oil supplement (Control), or diets of (DM basis) 3% linseed and fish oils (1:1, w/w, LSO-FO), or 3% sunflower and fish oils (1:1, w/w, SFO-FO), or 3% mixture (1:1:1, w/w) of linseed, sunflower, and fish oils (MIX-O). The animals fed SFO-FO had a 13.12% decrease in total dry matter intake compared with the control diet (p<0.05). No significant change was detected for milk yield; however, the animals fed the diet supplemented with SFO-FO showed a depressed milk fat yield and concentration by 35.42% and 27.20%, respectively, compared to those fed the control diet (p<0.05). Milk c9, t11-conjugated linoleic acid (CLA) proportion increased by 198.11% in the LSO-FO group relative to the control group (p<0.01). Milk C18:3n-3 (ALA) proportion was enhanced by 227.27% supplementing with LSO-FO relative to the control group (p<0.01). The proportions of milk docosahexaenoic acid (DHA) were significantly increased (p<0.01) in the cows fed LSO-FO (0.38%) and MIX-O (0.23%) compared to the control group (0.01%). Dietary inclusion of LSO-FO mainly increased milk c9, t11-CLA, ALA, DHA, and n-3 polyunsaturated fatty acids (PUFA), whereas feeding MIX-O improved preformed FA and unsaturated fatty acids (UFA). While the lowest n-6/n-3 ratio was found in the LSO-FO, the decreased atherogenecity index (AI) and thrombogenicity index (TI) seemed to be more extent in the MIX-O. Therefore, to maximize milk c9, t11-CLA, ALA, DHA, and n-3 PUFA and to minimize milk n-6/n-3 ratio, AI and TI, an ideal supplement would appear to be either LSO-FO or MIX-O.

Isolation of α-linolenic acid biohydrogenation products by combined silver ion solid phase extraction and semi-preparative high performance liquid chromatography.

Polyunsaturated fatty acids typically found in cattle feed include linoleic (LA) and α-linolenic acid (ALA). In the rumen, microbes metabolize these resulting in the formation of biohydrogenation products (BHP), which can be incorporated into meat and milk. Bioactivities of LA-BHP, including conjugated linoleic acid (cis (c) 9,trans (t) 11-18:2 and t10,c12-18:2) and trans fatty acid isomers (t9-, t10- and t11-18:1) have been investigated, but effects of several BHP unique to ALA have not been extensively studied, and most ALA-BHP are not commercially available. The objective of the present research was to develop methods to purify and collect ALA-BHP using silver ion (Ag(+)) chromatography in sufficient quantities to allow for convenient bioactivity testing in cell culture. Fatty acid methyl esters (FAME) were prepared from perirenal adipose tissue from a cow enriched with ALA-BHP by feeding flaxseed. These were applied to Ag(+)-solid phase extraction, and eluted with hexane with increasing quantities of acetone (1, 2, 10, 20%) or acetonitrile (2%) to pre-fractionate FAME based on degree of unsaturation and double bond configuration. Fractions were collected, concentrated and applied to semi-preparative Ag(+)-high performance liquid chromatography (HPLC) for the isolation and collection of purified isomers, which was accomplished using isocratic elutions with hexane containing differing amounts of acetonitrile (from 0.015 to 0.075%). Purified trans-18:1 isomers collected ranged in purity from 88 to 99%. Purity of the ALA-BHP dienes collected, including c9,t13-18:2, t11,c15-18:2 and t10,c15-18:2, exceeded 90%, while purification of other dienes may require the use of other complementary procedures (e.g. reverse phase HPLC).

Supplementation of herbal plants differently modulated metabolic profile, insulin sensitivity, and oxidative stress in transition dairy cows fed various extruded oil seeds

The study investigated the effects of a mixture of herbal plants (HM) and two sources of unsaturated fatty acids (FA), extruded linseed (LS) and soybean (SB), on metabolic profile, insulin sensitivity, and oxidative status of transition dairy cows. Thirty-two prepartum Holstein cows, blocked by parity and calving day, were randomly assigned to 1 of 4 treatments, in a 2×2 factorial design, starting from 25 days before the expected calving date to 26 days postpartum. The supplementation rates of HM were 150 and 170g/animal/day at pre- and postpartum, respectively. Blood samples were analyzed for metabolites on day 7.15±1.70 prepartum and on days 1 and 21 postpartum. An intravenous glucose tolerance test (IV-GTT) was conducted on day 25 postpartum. Data showed that cows supplemented with HM had lower serum concentration of NEFA (0.395 vs. 0.602±0.044mmol/L; P<0.01) and NEFA to insulin ratio (P<0.01) postpartum. Compared to animals fed SB-based diets, cows fed the LS-based diet had greater serum glucose concentration during prepartum (80.7 vs. 71.3±3.32mg/dL; P=0.06) and postpartum period (86.3 vs. 73.5±3.35mg/dL; P=0.01), as well as lower NEFA (0.425 vs. 0.572±0.044mmol/L; P=0.03) and insulin to glucose ratio (P<0.01) postpartum. Revised quantitative insulin-sensitivity check index revealed that supplementing HM in LS-based diet improved insulin sensitivity (0.45 vs. 0.41±0.013; P=0.03) prepartum, whereas after parturition, the HM addition was effective for both oil seeds (0.40 vs. 0.37±0.008; P=0.06) in enhancing insulin sensitivity. Result of IV-GTT indicated that cows fed LS-based diets had higher basal glucose concentration (63.7 vs. 55.7±2.37;mg/dL; P=0.02) and lower glucose area under the curve (995.8 vs. 1529.5±100.7;mg/dL×45min; P<0.01). Supplementing HM resulted in greater total antioxidant capacity prepartum (0.55 vs. 0.48±0.017nmol/L; P=0.01) and lower malondialdehyde concentration at prepartum (1.03 vs. 1.96±0.140μmol/L; P<0.01) and postpartum (1.32 vs. 1.88±0.178μmol/L; P=0.04). Although feeding LS ameliorated insulin resistance, this feeding strategy lowered total antioxidant capacity prepartum (0. 48 vs. 0.55±0.017nmol/L; P<0.01) and increased malondialdehyde concentration postpartum more than the SB diet (1.91 vs. 1.28±0.172μmol/L; P=0.02). Overall, both HM supplementation and LS feeding improved metabolic profile and insulin response following glucose infusion, although feeding of LS-based diets induced an increased oxidative stress.

Whole flax seed and flax oil supplementation of dairy cows fed high-forage or high-concentrate diets: Effects on digestion, ruminal fermentation characteristics, protozoal populations and milk fatty acid profile

The objective of this study was to examine the effects of whole flax seed (FS) and flax oil (FO) supplementation on digestion, ruminal fermentation, and milk fatty acid (FA) profile of dairy cows fed high-forage (HF) or high-concentrate (HC) diets. Four ruminally lactating cows were used in a 4×4 Latin square design with dietary treatments arranged as a 2×2 factorial. High forage and HC basal diets were formulated by varying the proportions of grass and corn silages, as well as those of corn grain and soybean meal. The basal diets were fed for ad libitum intake, and supplemented with either FS or FO at the feeding rate of 2.0 and 0.7kg/d, respectively. The forage:concentrate (F:C) ratios of the total diets (including top dressed FS or FO) were 700:300 and 300:700 on a dry matter (DM) basis for HF and HC, respectively. Increasing the concentrate proportion in the diet reduced ruminal pH, shifted volatile fatty acid (VFA) pattern toward more propionate and less acetate, and decreased protozoal numbers. These changes in ruminal fermentation resulted in a decrease of in sacco effective ruminal degradability (ERD) of acid detergent fiber (ADF) and neutral detergent fiber (aNFD) of grass silage. Despite alterations in rumen function, no interactions occurred between the proportion of concentrate in the diet and flax supplementation. Replacing FS with FO in the diet had no effect on dry matter intake (DMI) and ruminal fermentation characteristics, but increased organic matter (OM) digestibility and milk yield. An interaction between F:C and flax supplement was observed for the milk fat ratio of trans-11 18:1 to trans-10 18:1, which increased when FO replaced FS in HF diets, while the opposite was observed with HC diets. Feeding FS increased milk fat content and transfer efficiency of cis-9, cis-12, cis-15 18:3, the major FA present in flax, and decreased the concentration of trans intermediates of ruminal biohydrogenation as compared with FO.

Effects of diets supplemented with sunflower or flax seeds on quality and fatty acid profile of hamburgers made with perirenal or subcutaneous fat

Steers were fed grass hay or red clover silage based diets containing flaxseed or sunflower seed as sources of 18:3n−3 and 18:2n−6 respectively. Hamburgers were made from triceps brachii and perirenal or subcutaneous fat. Perirenal-hamburgers contained more polyunsaturated fatty acids (PUFA), several PUFA biohydrogenation intermediates (BHI), and 18:0 (P<0.05). Oxidative stability was similar across hamburgers (P>0.05). Sensory differences were found due to hamburger fat source, but were < one panel unit. Within perirenal-hamburgers, feeding flaxseed increased 18:3n−3 and its BHI (P<0.05), and feeding sunflower seed increased 18:2n−6 and its BHI (P<0.05). Feeding flaxseed increased off-flavour intensity and oxidation in perirenal-hamburgers (P<0.05). Feeding oilseeds in forage based diets while using perirenal fat to make hamburgers provides opportunities to increase PUFA and BHI with potential to impact human health, but control measures need to be explored to limit oxidation and off-flavours when feeding flaxseed.

Effect of dietary inclusion of triticale dried distillers' grain and oilseeds on quality and fatty acid profile of meat from feedlot steers

This study compared carcass, meat quality and fatty acid profiles of longissimus thoracis (LT) from feedlot cattle fed barley grain with or without oilseed (OS). Six diets containing no oilseed (No-OS), 10% ground flaxseed (FS), 10% high oleate sunflower seeds (SS) with or without 30% triticale dried distiller's grain (DDGS) were prepared. Feeding DDGS increased chroma at 24 and 144h post mortem. Feeding FS increased weight% of LT PUFA (P<0.05) compared to No-OS or SS. An OS by DDGS interaction occurred for 18:3n−3 (P<0.05) where FS increased weight% of 18:3n−3 (P<0.05), a response accentuated (P<0.05) by DDGS. Feeding DDGS increased weight% of LT 18:2n−6 (P<0.05), but neither OS nor DDGS affected conjugated linoleic acid (CLA, t7,c9 &c9,t11-18:2). Feeding FS increased weight% of n−3 FA, and both FS and SS increased t10-18:1 with no effect on CLA or t11-18:1. Combination feeding of DDGS and FS further increased weight% of n−3 FA and tempered increases in t10-18:1 with no effect on CLA or t11-18:1. The findings suggest a new strategy to increase beef omega-3 fatty acids efficiently through inclusion of a combination of DDGS and FS in feedlot diet.

Effect of feeding linseed oil in diets differing in forage to concentrate ratio: 1. Production performance and milk fat content of biohydrogenation intermediates of α-linolenic acid

To evaluate the interaction between the levels of dietary concentrate and linseed oil (LO) on milk fatty acid (FA) profile, 24 Holstein cows were used in a randomised complete block design based on days in milk, with a 2×2 factorial arrangement of treatments. Within each block, cows were fed one of four experimental diets containing 30% concentrate (LC) or 70% concentrate (HC), without LO (NLO) or with LO supplemented at 3% of dietary dry matter. Milk FA profiles were analysed with a special emphasis on the intermediates of the predominant trans-11, and a putative trans-13 pathways of ruminal biohydrogenation of cis-9, cis-12, cis-15 18:3. Feeding LO increased the concentrations of cis-9, cis-12, cis-15 18:3 and trans-11, cis-15 18:2 in milk fat, and these increases were of a higher magnitude when LO was added in HC as compared with LC diet (interaction of LO by concentrate). A treatment interaction was also observed for the level of trans-11 18:1 which was higher when feeding LO, but for which the increase was more pronounced with the LC as compared with HC diet. The concentrations of cis-15 18:1 and cis-9, trans-11, cis-15 18:3 were higher in cows fed LO, but feeding HC diets decreased milk fat content of cis-15 18:1 and a tendency for a decrease in cis-9, trans-11, cis-15 18:3 was apparent. Feeding LO increased milk fat content of trans-13 18:1 and cis-9, trans-13 18:2, while the concentrations of these two isomers were not affected by the level of dietary concentrates. The isomer cis-9, trans-13, cis-15 18:3 has not been detected in any of the milk samples. In conclusion, interactions were observed between LO and dietary concentrates on the proportions of some intermediates of the trans-11 biohydrogenation pathway. The presence of trans-13 18:1 and cis-9, trans-13 18:2 supports the existence of a trans-13 pathway, but an 18:3 intermediate with a trans-13 double bond has not been identified.

Effect of feeding linseed oil in diets differing in forage to concentrate ratio: 2. Milk lactone profile

Lactones are important contributors to the flavour and aroma of milk and dairy products. This study was conducted to evaluate the effects of dietary linseed oil (LO) and forage to concentrate ratio on milk lactone profile. Twenty four Holstein cows were used during a 4-week feeding trial in a randomised complete block design. Cows were fed diets containing 30% (LC) or 70% (HC) concentrate, and 0% (NLO) or 3% LO in a 2×2 factorial arrangement of treatments. Milk lactone profile was evaluated using the solid phase microextraction technique. The highest levels of δ-lactones (δ-6:0, δ-8:0, δ-10:0, and δ-12:0) were found with the LC/NLO diet. These concentrations were then decreased when cows received either a high level of concentrate or supplemental LO, but these effects were not additive (interaction of LO by concentrate, P<0·01). An interaction of LO by concentrate (P<0·01) was also noted on milk γ-12:0 for which the highest concentration was observed when supplementing LO in HC diet, while no effect was apparent when LO was added in LC diet. Moreover, feeding HC increased the level of γ-12:1 in milk as compared with LC, while LO had no effect on this γ-lactone. Finally, γ-12:2 was not detected in any of the milk samples studied. Organoleptic properties of milk were evaluated in a triangle test showing that a significant number of assessors perceived a difference between milk from cows fed LC/NLO as compared with milk from cows fed HC/LO. The sensory evaluation was completed by a ranking test where the intensities of fresh lactic, foreign and global flavours were not different between treatments. In conclusion, feeding LO in HC diet modified milk lactone profile with a shift toward more γ- and less δ-lactones as compared with LC diet not supplemented with LO. A difference was perceived in a triangle test between milk from these two treatments, but the sensory attributes responsible for this difference have not been identified in the current trial.

Retention of n-3 polyunsaturated fatty acids in trimmed loin and belly is independent of timing of feeding ground flaxseed to growing-finishing female pigs1

A serial slaughter study, involving 45 individually housed Yorkshire female pigs, was conducted to evaluate the impact of feeding diets containing ground flaxseed (FS) during either the grower or late finisher phase on the incorporation of α-linolenic acid (18:3n-3) and n-3 highly unsaturated fatty acid metabolites (n-3 HUFA; all n-3 PUFA excluding 18:3n-3) in trimmed loin (longissimus dorsi) and belly (cross-section cut). Growth performance, carcass characteristics, and pork quality were also monitored. The three feeding regimens were 1) feeding a diet containing 10% FS between 25 and 50 kg BW, followed by FS-free diets (low n-3 PUFA content) until 110 kg BW (FS early, FSE; n = 16), 2) feeding no FS diets between 25 and 85 kg BW, followed by a diet containing 6% FS until 110 kg BW (FS late, FSL; n = 17), and 3) feeding FS-free diets between 25 and 110 kg BW (CON; n = 8). Pigs were assigned to 1 of 3 target slaughter weights for determining whole nutrient retention: 50 kg (n = 4 and 5 for FSE and FSL, respectively), 85 kg (n = 4 for FSE and FSL), and 110 kg (n = 8 pigs for FSE, FSL, and CON). An additional 4 pigs were slaughtered to determine initial body composition at 25 kg BW. Pigs on treatments FSE and FSL consumed equal cumulative amounts of FS (5.1 vs. 5.2 kg). Fatty acid content was expressed as milligrams per 100 g of fresh tissue. No treatment effect was observed for growth performance, body composition, carcass characteristics, loin meat quality, and fat content in the loin and belly samples. In the loin, the content of 18:3n-3 at 110 kg BW was greater for FSL than FSE and CON (P < 0.01; 143, 76.4, and 37 mg/100 g, respectively), whereas the contents of 18:3n-3 in the belly were greater for both FSL and FSE than CON (752, 667, and 207 mg/100 g for FSL, FSE, and CON, respectively). Within tissues, the content of n-3 HUFA was similar for FSL and FSE, and both were greater (P < 0.01) than CON for loin (41.7, 30.3, and 17.9 mg/100 g, respectively) and belly (168, 179, and 71.2 mg/100 g, respectively), except for docosahexaenoic acid (22:6n-3) in the loin. Feeding FS tended to reduce the content of arachidonic acid (20:4n-6) and adrenic acid (22:4n-6; P < 0.10) in the loin and belly. In the belly but not in the loin, feeding FS reduced the content of total SFA (P = 0.05) and tended to reduce the content of the sum of MUFA (P = 0.09). Within the loin and belly, the ratio of n-6 to n-3 PUFA and the content of n-3 HUFA were similar for FSE and FSL, with the exception of 18:3n-3 and 20:4n-6 in the loin, for which contents were greater for FSL than FSE (P < 0.05). These results indicate that providing modest amounts of FS leads to a substantial enrichment of 18:3n-3 and n-3 HUFA in pork products. The enrichment of n-3 HUFA appears to be independent of timing of feeding FS, providing flexibility as to when n-3 PUFA can be fed to generate n-3 PUFA-enriched pork products.

Performance and Fatty Acid Composition of Adipose Tissue, Breast and Thigh in Broilers Fed Flaxseed: A Review

Interest on the enrichment of poultry meat with n-3 fatty acids has increased given its important role in human health. Flaxseed is the main sources of n-3 fatty acids, and contains between 45 to 71% of total fatty acids of the oil as α-linolenic acid. This paper reviews the plausibility of n-3 enrichment. Its focus is on the processing of flaxseed and begins by summarizing the benefits of supplementation on broiler performance. The literature on altering the FA deposition in different tissues is then reviewed, and the factors that affect the incorporation of n-3 PUFA into edible tissues of poultry are investigated. Flaxseed supplementation caused a reduction in the abdominal fat pad, and the main fatty acid deposited in the tissue is LNA. The use of fold-change analysis allowed interpreting and determining the variation of results within experiments that do not report data in similar units of measure. The fold change analysis identified three categories of desaturation response to feeding flaxseed to broilers, resulting in different values for EPA and DHA in both breast and thigh tissues: high, medium and low fold-changes. The use of flaxseed oil, whole or ground flaxseed 14 to 21 day before slaughter is recommended to poultry producers as feeding strategies to optimize n-3 enrichment, without compromising animal performance. Enriched DHA deposition could be accomplished feeding whole flaxseed.

Short communication: Feeding linseed oil to dairy goats with competent reticular groove reflex greatly increases n-3 fatty acids in milk fat

A crossover experiment was designed to compare the effects of 2 ways of feeding linseed oil on milk fat fatty acid (FA) composition. Ten lactating goats, trained to keep competent their inborn reticular groove reflex, received a daily dose of linseed oil (38g/d) either with their solid (concentrate) feed (CON) or emulsified in skim milk and bottle-fed (BOT). Two groups of 5 goats received alternative and successively each of the treatments in two 15-d periods. α-Linolenic acid in milk fat rose up to 13.7% in the BOT versus 1.34% in the CON treatment. The n-6 to n-3 FA ratio was significantly reduced in goats receiving bottle-fed linseed oil (1.49 vs. 0.49). Contents of rumen biohydrogenation intermediates of dietary unsaturated FA were high in milk fat of goats under the CON treatment but low in those in the BOT treatment. These results point to a clear rumen bypass of the bottle-fed linseed oil. This strategy allows obtaining milk fat naturally very rich in n-3 FA and very low in trans FA. Translating this approach into practical farm conditions could enable farmers to produce milk enriched in specific FA.

Effects of feeding flaxseed or sunflower-seed in high-forage diets on beef production, quality and fatty acid composition

Yearling steers were fed 70:30 forage:concentrate diets for 205d, with either grass hay (GH) or red clover silage (RC) as the forage source, and concentrates containing either sunflower-seed (SS) or flaxseed (FS), each providing 5.4% oil to diets. Feeding diets containing SS versus FS significantly improved growth and carcass attributes (P<0.05), significantly reduced meat off-flavor intensity (P<0.05), and significantly increased intramuscular proportions of vaccenic (t11-18:1), rumenic (c9,t11-CLA) and n−6 fatty acids (FA, P<0.05). Feeding diets containing FS versus SS produced significantly darker and redder meat with greater proportions of atypical dienes (P<0.05). A significant forage×oilseed type interaction (P<0.05) was found for n−3 FA, α-linolenic acid, and conjugated linolenic acid, with their greatest intramuscular proportions found when feeding the RC-FS diet. Feeding GH versus RC also significantly improved growth and carcass attributes, sensory tenderness (P<0.05) and significantly influenced intramuscular FA composition (P<0.05), but overall, forage effects on FA profiles were limited compared to effects of oilseed.

Adipose tissue and muscle fatty acid profiles of steers fed red clover silage with and without flaxseed

The current study examined the effects of inclusion of flaxseed in a red clover silage diet on growth, carcass quality, adipose tissue and muscle fatty acid (FA) profiles of beef steers. Twelve British×Continental crossbred steers (363±26.5kg) were randomly assigned to two pens and fed diets containing 70% red clover silage, 15% steam rolled barley/vitamin–mineral supplement and either additional 15% steam rolled barley or 15% triple rolled flaxseed (all DM basis) for 215d. Diet had no effect (P>0.05) on average daily gain or carcass quality atributes. Overall, FA profiles in all tissues followed similar trends when flaxseed was added to the diet but intramuscular fat had the highest proportions of n-3 and n-6 polyunsaturated FA (PUFA) while subcutaneous fat had largest proportions of conjugated linoleic acids (CLA) and perirenal fat had the highest proportions of trans-18:1 isomers, particularly vaccenic acid (VA). Feeding flaxseed increased (P<0.05) percentages of α-linolenic acid (ALA; 1.1–1.6% of total FA), total n-3 PUFA, conjugated linolenic acids, non-conjugated linoleic acids (mostly t11,c15-18:2), and led to unprecedented increases in CLA (mainly rumenic acid, RA; 1.1–2.9%), and trans-18:1 isomers (chiefly VA; 5.9–9.5%) in muscle and adipose tissues. Flaxseed also reduced individual and total n-6 PUFA, cis-monounsaturated FA, branched-chain FA and saturated FA (mainly 16:0) in beef lipids. Overall, feeding flaxseed in a red clover silage diet enhanced the levels of FA with a positive health image (ALA, 2-fold; RA, 3 to 4-fold and VA, 4 to 5-fold) and reduced the levels of less desirable FA (n-6 PUFA; 14:0, 16:0) in muscle and adipose tissues without adverse effects on growth and carcass quality. Differences in tissue FA composition were also noted, and high levels of VA in perirenal fat in particular have potential for use in testing for health effects and development of value added beef and other food products.

Intake and digestion of fatty acids by dairy cows fed whole flaxseed and Ca salts of flaxseed oil

Four ruminally lactating Holstein cows averaging 602kg of body weight and 64 days in milk were randomly assigned to a 4×4 Latin square design to determine the effects of feeding whole flaxseed and calcium salts of flaxseed oil on intake and total tract apparent digestibility (TTAD) of fatty acids (FA) and apparent transfer of linolenic acid in milk fat. The treatments were for ad libitum intake: a control diet with no flaxseed products (CON) or a diet of 42g/kg dry matter (DM) whole flaxseed (FLA), 19g/kg DM calcium salts of flaxseed oil (SAL) or 23g/kg DM whole flaxseed and 8g/kg DM calcium salts of flaxseed oil (MIX). Experimental periods consisted of 21 d of diet adaptation and 7d of data collection and sampling. Intake of α-linolenic acid (cis9,12,15-18:3) was similar for cows fed FLA, SAL, and MIX and higher than for those fed CON. Output of linolenic acid in faeces was higher for cows fed FLA, followed by those fed MIX, CON, and SAL. Output of α-linolenic acid in milk tended (P=0.07) to be lower for cows fed CON than for those fed the other diets and there was no difference between cows fed FLA, SAL, and MIX. Although intake of α-linolenic acid was lower for cows fed CON than for those fed the other diets, transfer efficiency (g per 100g of α-linolenic acid consumed) was higher for cows fed the former diet. Feeding FLA, SAL, and MIX resulted in similar apparent transfer of α-linolenic acid in milk. Cows fed FLA had the lowest TTAD of linolenic acid. The high digestibility of Ca-salts of flaxseed oil accounts for the interest in using it in practical applications for feeding cows. However, as previous results have shown that the use of Ca-salts of flaxseed oil did not allow a large modification in milk fat composition, the cheapest flaxseed product will be recommended to incorporate in the dairy cow diet.

Inclusion of Flaxseed in Hay‐ and Barley Silage Diets Increases Alpha‐Linolenic Acid in Cow Plasma Independent of Forage Type

Feeding flaxseed to cattle may be a means of increasing omega-3 fatty acid levels in ruminant products, but possible interactions with conserved forages have not been investigated. Twelve Holstein cows were used in a replicated 4×4 Latin Square experiment. Cows were fed one of four 50:50 forage:concentrate diets (DM basis): hay (hay control, HC), hay plus 15% ground flaxseed (hay-flaxseed, HF), barley silage (silage control, SC), and barley silage plus 15% ground flaxseed (silage-flaxseed, SF). Plasma concentrations of alpha-linolenic acid (ALA) did not differ between SC and HC diets. Flaxseed increased ALA (P<0.05), but levels were not influenced by forage type. Flaxseed slightly increased 18:2n-6 (P<0.05) and some n-6 and n-3 elongation and desaturation products, particularly arachidonic acid (ARA) and eicosapentaenoic acid (EPA). Flaxseed also increased C18:0 (P<0.05) with this increase being greater (P<0.01) for cows fed SF than HF. Feeding flaxseed also increased plasma C18:1-trans isomers (P<0.01), predominantly vaccenic acid (VAA, 18:1-t11), with this increase being greater (P<0.05) in cows fed HF than SF. Although conjugated linoleic acid (CLA) was increased (P<0.001) with flaxseed it was not influenced by forage type (P=0.06). Overall, feeding flaxseed increased plasma ALA, EPA, ARA and CLA independently of forage type. Feeding flaxseed with silage, however, resulted in more 18:0, while feeding flaxseed with hay resulted in greater accumulations of plasma 18:1-trans isomers mainly in the form of VAA.

Effects of vitamin E and flaxseed on rumen-derived fatty acid intermediates in beef intramuscular fat

To elucidate the effects of dietary vitamin E with or without flaxseed on beef fatty acid composition, 80 feedlot steers were fed 4 diets: Control-E (451IUdl-α-tocopheryl acetate/head/day), Control+E (1051IUdl-α-tocopheryl acetate/head/day), Flax-E (10% ground) and Flax+E. Vitamin E had no effect on animal growth or carcass weight (p>0.05), while flaxseed-fed steers had greater average daily gain (p=0.007), final live weight (p=0.005) and heavier carcasses (p=0.012). Feeding flaxseed increased the total n−3 fatty acid content of beef and this response was further accentuated by the inclusion of high levels of vitamin E in the diet. Feeding flax increased levels of some 18:3n−3 partial hydrogenation products including c15- and t13/14-18:1 and several 18:2 isomers (p<0.001) but decreased t10-18:1 (p<0.001). Vitamin E enhanced intramuscular levels of 18:3n−3 and its biohydrogenation products leading to greater accumulations of total n−3 fatty acids in lean ground beef. The consequences of increasing the concentrations of partially hydrogenated products on human health have yet to be investigated.