In India, the restriction of genetically modified (GM) crops and derived products not approved in the country necessitates surveillance for transgene(s) in plant material/products imported into the country. CDC Triffid expressing acetolactate synthase (ALS) conferring tolerance to sulphonylurea herbicide is the only GM flax event that has got approval in Canada in 1990s and subsequently deregistered in 2001. In spite of deregistration, the unexpected and unauthorized detection of traces of GM flax in the consignments imported from Canada to Europe has further necessitated the stringent monitoring of flax shipments from Canada for suspected GM incidents. This study reports on the detection of transgenic elements being present in GM flax employing polymerase chain reaction assays, in a set of 123 flaxseed accessions imported from Canada for research purpose. Based on the tests conducted, none of the transgenic elements, namely, nos promoter (P-nos), nos terminator (T-nos), nptII marker gene, ALS transgene, as present in the GM flax CDC Triffid were detected in any of the tested accessions. The well-known herbicide tolerance gene cp4-epsps, being employed in Roundup® Ready events of other crops, was also not detected in these samples. This case study has demonstrated the importance of monitoring the presence of transgene(s) in flaxseed imports, and such studies need to be carried out for the imported seeds from the country where GM events of respective crop are being approved whereas they have not been approved in the country of import as a part of precautionary approach.

The present study aimed to use an in vitro follicle culture (IVFC) biotechnique as a tool to evaluate the influence of whole flaxseed as a feed supplementation in the diet on the in vitro development of caprine early antral follicles (EAFs) and further embryo production. In total, 18 adult goats were homogeneously allocated into two diet groups: Control and Flaxseed. EAFs from both experimental groups (300–400 µm) were isolated and cultured in vitro for 18 days. After IVFC, recovered cumulus–oocyte complexes were submitted to in vitro maturation, and subsequently to IVF and in vitro embryo culture. The endpoints evaluated were follicular growth and morphology, oocyte recovery rate and diameter, sperm penetration, pronuclei formation, embryo development, and estradiol production. The addition of the whole flaxseed in the diet did not affect (P > 0.05) follicular growth and diameter. A higher (P < 0.05) percentage of oocytes ≥ 110 µm was recovered from the flaxseed treatment. However, the sperm penetration rate was higher (P < 0.05) in the control treatment when compared with the flaxseed treatment, but no differences were found regarding the rate of fertilization nor cleaved embryos. In conclusion, dietary flaxseed increased the recovery rate of fully grown oocytes, but it did negatively affect the sperm penetration rate, even though there was no further effect on the cleavage rate.

Anti-inflammatory agents such as long-chain n-3 fatty acids have been recognised to improve disease-related fatigue. We hypothesised that α-linolenic acid may also benefit in reduction of fatigue in low-grade inflammation such as overweight/obesity. Seventy-two healthy children and adolescents with BMI > 25 kg/m2 were randomised to flaxseed (n 38) and puffed wheat (n 34) groups. Participants consumed isoenergetic amounts of either 20 g/d flaxseed or 25 g/d puffed wheat for 4 weeks. Fatigue, mood feelings (depression, anxiety and stress), appetite, energy intake, weight, height and waist circumference were measured. Analysis was performed based on per-protocol and intention-to-treat (ITT) approaches. Consumption of flaxseed decreased mental fatigue and caused a significant between-group difference (P < 0·001). Although no significant change in physical and total score of fatigue was observed in either group, a significant between-group difference occurred due to a more remarkable change in these parameters in the flaxseed group. General fatigue, motivation, activity and mood feelings did not change significantly between groups. Flaxseed showed less benefit than puffed wheat on anthropometric measures as it caused a smaller increase in height (0·53 (sd 0·89) v. 1·09 (sd 0·87) cm, P = 0·03) and reduction in BMI (–0·25 (sd 0·63) v. −0·67 (sd 0·56) kg/m2, P = 0·01) than puffed wheat. Appetite and waist circumference decreased in both groups, but no significant difference was observed between groups. In ITT analysis, only alteration in mental fatigue was significant. In conclusion, consumption of flaxseed may improve mental fatigue in children with overweight/obesity. However, because of smaller increase in height, it is better to hinder administration of flaxseed during periods of growth.

Feeding livestock with n-3 fatty acid (FA) sources (linseed, for example) is a common strategy to improve lipid quality of meat and milk products. However, in monogastric animals, linseed tegument decreases digestibility and alphalinolenic acid (ALA) uptake, while the whole linseed is well used by ruminants. In a context of increasing sustainability of feeding systems, providing monogastric animals and ruminants with linseed products adapted to their digestive systems is an important issue. This research paper addresses the hypotheses: (i) sieved extruded linseed (SEL) specific for ruminants is as or more effective than standard extruded linseed (ii) microalgae DHA Gold® is an interesting source of docosahexaenoic acid (DHA) in feedstuff and (iii) the effects of SEL and microalgae on milk characteristics are complementary and additive. Thirty-two cows were divided into 4 groups with different dietary n-3 fatty acid sources using a continuous design. All the diets were fed as mixed rations based on maize silage, energy concentrate and soybean meal. The first group received a control diet (CTRL) with no additional fat. The 3 other groups received SEL, microalgae DHA Gold® (ALG) and a mixture of microalgae DHA Gold® and SEL (SEL/ALG). Milk was collected from morning milkings after six weeks of dietary treatment. In SEL and SEL/ALG, ALA increased (+0·32 and +0·26% unit, respectively), and DHA increased in ALG and SEL/ALG (+0·43 and +0·15% unit, respectively) compared to CTRL, as a consequence of the initial composition of the n-3 FA sources. In SEL, milk yield, fat and protein contents, milk fat globule size and spontaneous lipolysis (measured to evaluate suitability for milk processing) were not different compared with CTRL. In ALG and SEL/ALG, milk yield decreased (−2·8 and −6·0 kg/d, respectively), fat content was halved, and fat globule size was reduced (−1·46 and −1·31 µm, respectively) compared to CTRL. Spontaneous lipolysis increased in ALG (+0·12 mEq/kg of milk) compared to CTRL. Protected microalgae and the doses of microalgae in the diet need further investigation to prevent FA modification in the rumen and the consequent deleterious effects on milk fat.

The present study aimed to evaluate growth performance and meat quality of broiler chicken with respect to feeding of 100 g flaxseed meal (FM)/kg and increasing lysine levels in the broiler diet. The results revealed no effect of lysine and FM feeding on growth performance except for a negative effect of FM on feed efficiency of birds, which was countered by feeding 1.25 BIS lysine. Feeding FM improved the fatty acid profile of broiler chicken meat significantly, whereas no effect was observed for increasing lysine levels beyond BIS recommendation. FM significantly reduced meat cholesterol, fat, water-holding capacity (WHC), extract release volume (ERV) and antioxidant potential, whereas it increased the pH of fresh meat, drip loss and lipid peroxidation of broiler chicken meat. As compared with other lysine levels, generally 1.25 BIS lysine significantly increased the pH of refrigerated stored meat, WHC, ERV and antioxidant potential, whereas it significantly reduced cholesterol, fat, drip loss and lipid peroxidation of broiler chicken meat. Thus, the inclusion of 100 g FM/kg diet along with 1.25 BIS lysine in broiler ration was optimum for desirable broiler performance, fatty acid profile, oxidative stability and other functional properties of broiler chicken meat.

Health benefits of fatty acids (FA) of the n-3 family have been well documented. The current consumption of n-3 FA by humans is below the recommended intake in Western countries. There are two sources of n-3 FA: α-linolenic acid (18-3 n-3, ALA) from terrestrial sources and long chain 20 and 22 carbon n-3 FA from marine oils. There is an increased interest in developing food products such as eggs and meat enriched with n-3 FA to meet the human requirement. In this context, poultry food lipids are a highly targeted and well-researched food item. Among the different feed sources, flaxseed, owing to its high fat (~40-42%) and ALA (>50%) contents along with other nutritional properties (e.g., metabolisable energy, protein content), is the most common feed ingredient explored for n-3 FA enrichment. This review attempts to bring together the use of flaxseeds in poultry feeds and its role in meeting the human requirements of n-3 FA through n-3 FA enriched foods. The antinutritional factors (ANF) present in flaxseeds and ways to mitigate the negative effects of ANF in poultry feeding are also included.

Flaxseed is a rich source of α-linolenic acid and phytoestrogens, mainly lignans, whose metabolites (enterodiol and enterolactone) can affect estrogen functions. The present study evaluated the influence of dietary flaxseed supplementation on reproductive performance and egg characteristics (fatty acids, cholesterol, lignans and isoflavones) of 40 Hy-Line hens (20/group) fed for 23 weeks a control diet or the same diet supplemented with 10% of extruded flaxseed. The flaxseed diet had approximately three times the content of lignans (2608.54 ng/g) as the control diet, mainly secoisolariciresinol diglucoside (1534.24 v. 494.72 ng/g). When compared with the control group, hens fed flaxseed showed a similar deposition rate (72.0% v. 73.9%) and egg yield. Furthermore, there was no effect of flaxseed on the main chemical composition of the egg and on its cholesterol content. Estradiol was higher in the plasma of the control group (1419.00 v. 1077.01 pg/ml) probably due to the effect of flaxseed on phytoestrogen metabolites. The plasma lignans were higher in hens fed flaxseed, whereas isoflavones were lower, mainly due to the lower equol value (50.52 v. 71.01 ng/ml). A similar trend was shown in eggs: the flaxseed group had higher level of enterodiol and enterolactone, whereas the equol was lower (198.31 v. 142.02 ng/g yolk). Secoisolariciresinol was the main lignan in eggs of the flaxseed group and its concentration was three times higher then control eggs. Flaxseed also improved the n-3 long-chain polyunsaturated fatty acids of eggs (3.25 v. 0.92 mg/g egg), mainly DHA, however, its oxidative status (thiobarbituric reactive substances) was negatively affected. In conclusion, 10% dietary flaxseed did not affect the productive performance of hens or the yolk cholesterol concentration, whereas the lignans and n-3 polyunsaturated fatty acid content of eggs improved. Further details on the competition between the different dietary phytoestrogens and their metabolites (estrogen, equol, enterodiol and enterolactone) should be investigated.

The research reported in this Research Communication was undertaken to evaluate the effects of different sources of polyunsaturated fatty acids (PUFA) supplemented in the diet on milk production and milk fatty acid profile of lactating ewes exposed to long term heat stress. The experiment was conducted during summer, involved 32 ewes divided into 4 groups of 8 each, and lasted 6 weeks. The ewes in all groups were fed twice daily and received 1·8 kg/d of oat hay and 1 kg/d of concentrate. Flaxseed group (FS) was supplemented with 250 g/d of whole flaxseed, Ascophyllum nodosum group (AG) was supplemented with 25 g/d of seaweed Ascophyllum nodosum, and the combination group (FS + AG) received both flaxseed and Ascophyllum nodosum supplementation. The control group (CON) was fed with 1 kg/d of pelleted concentrate without PUFA supplementation. Milk samples were collected twice daily per week, and analysed for fat, total protein, casein, and lactose content. At the beginning and then at 2, 4 and 6 week of the experiment each milk sample was analysed for milk fatty acids. Temperature-humidity index (THI) was calculated daily. Supplementation of flaxseed and of the combination of flaxseed and Ascophyllum nodosum increased milk yield. The total content of saturated fatty acids (SFA) in milk decreased for ewes fed FS, followed by FS + AG. On the contrary, monounsaturated fatty acids (MUFA) increased for ewes fed FS and FS + AG. The total n-3 FA was found higher in FS and FS + AG than in AG and CON groups mainly because of the increase in C 18 : 3 n-3 in FS and FS + AG milk. Milk from FS + AG resulted in the highest n-3/n-6 ratio and decreases in atherogenic and thrombogenic indices. The combination of seaweed Ascophyllum nodosum and flaxseed can be suggested as an adequate supplementation to sustain milk production and milk fatty acid profile of sheep during summer season.

Obesity and osteoporosis may have their origins in early postnatal life. This study was designed to evaluate whether flaxseed flour use during lactation period bears effect on body adiposity and skeletal structure of male rat pups at weaning. At birth, male Wistar rats were randomly assigned to control and experimental (FF) groups, whose dams were treated with control or flaxseed flour diet, respectively, during lactation. At 21 days of age, pups were weaned to assess body mass, length and composition by dual-energy X-ray absorptiometry. The animals were then sacrificed to carry out analysis of serum profile, intra-abdominal adipocyte morphology and femur characteristics. Differences were considered significant when P<0.05. The FF group displayed the following characteristics (P<0.05): higher body mass, length, bone mineral content, bone area and concentrations of osteoprotegerin, osteocalcin and high-density lipoprotein cholesterol; higher levels of stearic, α-linolenic, eicosapentaenoic and docosapentaenoic acids and lower levels of arachidonic acid and cholesterol; smaller adipocyte area; and higher mass, epiphysis distance, diaphysis width, maximal load, break load, resilience and stiffness of femur. Flaxseed flour intake during lactation period promoted adipocyte hypertrophy down-regulation and contributed to pup bone quality at weaning.

Flaxseed (Linum usitatissimum L.) has been a focus of interest in the field of functional foods because of its potential health benefits. However, we hypothesised that maternal flaxseed intake during lactation could induce several metabolic dysfunctions in adult offspring. In the present study, we aimed to characterise the adrenal function of adult offspring whose dams were supplemented with whole flaxseed during lactation. At birth, lactating Wistar rats were divided into two groups: rats from dams fed the flaxseed diet (FLAX) with 25 % of flaxseed and controls dams. Pups received standard diet after weaning and male offspring were killed at age 180 days old to collect blood and tissues. We evaluated body weight and food intake during development, corticosteronaemia, adrenal catecholamine content, hepatic cholesterol, TAG and glycogen contents, and the protein expression of corticotropin-releasing hormone (CRH), adrenocorticotropic hormone (ACTH), 11-β-hydroxysteroid dehydrogenase type 1 (11β-HSD1) and adrenaline β2 receptor at postnatal day 180 (PN180). After weaning, pups from the FLAX group had a higher body weight (+10 %) and food intake (+10 %). At PN180, the FLAX offspring exhibited higher serum corticosterone (+48 %) and lower adrenal catecholamine ( − 23 %) contents, lower glycogen ( − 30 %), higher cholesterol (4-fold increase) and TAG (3-fold-increase) contents in the liver, and higher 11β-HSD1 (+62 %) protein expression. Although the protein expression of hypothalamic CRH was unaffected, the FLAX offspring had lower protein expression of pituitary ACTH ( − 34 %). Therefore, induction of hypercorticosteronaemia by dietary flaxseed during lactation may be due to an increased hepatic activation of 11β-HSD1 and suppression of ACTH. The changes in the liver fat content of the FLAX group are suggestive of steatosis, in which hypercorticosteronaemia may play an important role. Thus, it is recommended that lactating women restrict the intake of flaxseed during lactation.

The aim of this study was to evaluate the effects of geese’s maternal diet supplemented with flaxseed on the fatty acid profiles of egg yolks and the antioxidant status of their offspring. A total of 288 female Huoyan geese (42 weeks old) were randomly allotted to four experimental groups in this 56-day experiment and fed on diets containing flaxseed at 0% (control), 5%, 10% and 15%, respectively. There were nine replicate pens per treatment, with eight geese per replicate pen. The concentration of α-linolenic acid (linear, P<0.01), EPA (20:5n-3; linear, P<0.01), DHA (22:6n-3; quadratic, P=0.03) and n-3 polyunsaturated fatty acid (PUFA) (linear, P<0.01) levels in the yolk lipids increased with increasing dietary flaxseed levels. Yolk palmitic acid (16:0, linear, P=0.05), saturated fatty acid (linear, P=0.04) level and total n-6/n-3 ratio (P<0.01) decreased in a linear fashion as dietary flaxseed levels increased. Increasing dietary flaxseed levels linearly decreased (P=0.01) the total cholesterol in egg yolks. After hatching, three 1-day-old gosling were selected randomly from each replicate to determine blood characteristics and liver antioxidant status. Aspartate aminotransferase activity (linear, P=0.03), total triglycerides (linear, P=0.02) and total cholesterol (linear, P=0.05) contents in blood linearly decreased as the levels of flaxseed increased. A linear dose response to maternal dietary flaxseed was detected for the activities of the goslings’ liver enzymes catalase (linear, P=0.01), superoxide dismutase (linear, P<0.01) and glutathione peroxidase (linear, P<0.01). The malondialdehyde (quadratic, P=0.03) and alkaline phosphatase content in the livers of goslings decreased as flaxseed supplementation levels increased. In conclusion, the dietary addition of flaxseed up to 15%, in the maternal diet resulted in increased n-3 PUFA levels in egg yolks and improved the antioxidant status of offspring in a dose-dependent manner.

The precocious interruption of lactation is a prime factor for developmental plasticity. Here we analyzed whether flour or flaxseed oil treatment contributes to body and brain mass in male rats subjected to early weaning. Pups were weaned for separation from their mother at 14 (early weaning, EW) and 21 days (control, C). At 21 days, some of the pups were evaluated (C21 v. EW21). After 21 days, control pups (C60) were fed a control diet. EW pups were divided into those fed a control diet (EWC60), those given flaxseed flour (EWFF60), and those given flaxseed oil (EWFO60) until 60 days. EW21 showed lower body and absolute brain mass and higher relative brain mass. At 60 days, EWC60 and EWFO60 had lower body mass. With regard to relative brain mass, EWC60 was heavier; EWFO60 had lower values compared with EWC60 and higher values compared with C60 and EWFF60. These results indicated that flaxseed flour, in comparison with flaxseed oil, contributes to brain development after EW.

The objective of the present study was to find the optimum dose of flaxseed that would decrease PG and alter oestrogen pathway endpoints implicated in ovarian cancer. In the study, four groups of fifty 1·5-year-old chickens were fed different amounts of flaxseed (0, 5, 10 or 15 % of their total diet) for 4 months and were then killed to collect blood and tissues. Levels of flaxseed lignan metabolites, Enterolactone (EL) and Enterodiol (ED) were measured in the serum, liver and ovaries by liquid chromatography–MS/MS, and n-3 and n-6 fatty acid (FA) levels were measured by GC. The effects of the varied flaxseed doses were assessed by measuring levels of PGE2 and oestrogen metabolites (16-hydroxyestrone (16-OHE1) and 2-hydroxyestrone (2-OHE1)) as well as by analysing the expression of the oestradiol metabolising enzymes CYP3A4 (cytochrome p450, family 3, subfamily A, polypeptide 4), CYP1B1 (cytochrome p450, family 1, subfamily B, polypeptide 1) and CYP1A1 (cytochrome p450, family 1, subfamily A, polypeptide 1) and that of oestrogen receptor α (ERα) in the ovaries. The ratio of n-3:n-FA increased with an increase in flaxseed supplementation and corresponded to a dose-dependent decrease in cyclo-oxygenase-2 protein and PGE2 levels. EL and ED increased in the serum, liver and ovaries with increased concentrations of flaxseed. Flaxseed decreased the expression of ERα in the ovaries. The ratio of 2-OHE1:16-OHE1 in the serum increased significantly in the 15 % flaxseed diet, and there was a corresponding increase in CYP1A1 in the liver and decrease in CYP3A4 in the ovaries. CYP1B1 mRNA also decreased with flaxseed diet in the ovaries. The 15 % flaxseed-supplemented diet significantly decreased inflammatory PGE2, ERα, CYP3A4, CYP1B1 and 16-OHE1, but it increased CYP1A1 and 2-OHE1, which thus reduced the inflammatory and pro-carcinogenic micro-environment of the ovaries.

The aim of the present study was to evaluate the effect of flaxseed on choroid–sclera complex thickness and on LDL oxidation in the sclera, choroid and retina of diet-induced hypercholesterolaemic rabbits. New Zealand male albino rabbits (n 21) were divided into two groups: group 1 (G1; n 11), fed a hypercholesterolaemic diet, and group 2 (G2; n 10), fed a hypercholesterolaemic diet enriched with flaxseed flour. The serum concentrations of total cholesterol (TC), LDL-cholesterol (LDL-C), HDL-cholesterol, TAG and fasting blood glucose were determined at the start of the experiment and on the day of killing (8th week). Choroid and sclera samples were subjected to haematoxylin–eosin (HE) staining and histomorphometric and immunohistochemical analyses with the anti-oxidised LDL antibody. Sensory retina samples were subjected to an immunohistochemical analysis with the primary monoclonal nitrotyrosine antibody. At the end of the experiment, a significant increase was observed in TC and LDL-C concentrations in G1 rabbits when compared with G2 rabbits (P= 0·008 and P= 0·02, respectively). HE staining revealed a significant increase in choroid–sclera complex thickness in G1 rabbits when compared with G2 rabbits (P< 0·001). Immunohistochemical analysis of choroid and sclera samples with the anti-oxidised LDL marker revealed a significant increase in immunoreactivity in G1 rabbits when compared with G2 rabbits (P< 0·001). Immunohistochemical analysis of sensory retina samples with the anti-nitrotyrosine marker revealed a significant increase in immunoreactivity in G1 rabbits when compared with G2 rabbits (P= 0·002). Flaxseed reduced the choroid–sclera complex thickness of diet-induced hypercholesterolaemic rabbits and the expression of oxidised LDL in the choroid–sclera complex as well as the expression of nitrotyrosine in the sensory retina.

Twenty-four 3-year-old Angus cows (512.2±21.6 kg) and six ruminally cannulated beef heifers (523.1±16.9 kg) were used to determine the impact of feeding oilseeds starting at the beginning of estrous synchronization until maternal recognition of pregnancy on plasma fatty acid composition. Starting ~60 days postpartum cows were synchronized with the Select Synch+controlled internal drug-release (CIDR) device and timed artificial insemination (AI) protocol. The day CIDR was inserted; cattle were randomly assigned to one of the three treatments being grazing only (CON) or a supplement containing whole soybeans (SOY); or whole flaxseed (FLX). Cattle continued to receive these diets for 28 days. Blood was collected every 3 days until 10 days after insemination and then every day until 18 days after insemination. All cattle grazed a common pasture and supplemented cattle were individually fed their respective supplements once daily. Ruminally cannulated heifers were used to evaluate the impact supplements had on forage intake, which was reduced (P=0.05) with oilseed supplementation. Feeding oilseeds increased total fatty acid intake (P<0.001) across treatments with SOY having greater (P<0.001) 18:2n-6 intake than either CON or FLX. Likewise, cattle fed FLX had greater (P<0.001) 18:3n-3 intake than either CON or SOY. There was a treatment×time interaction (P⩽0.05) for all fatty acids identified except for 20:5n-3 (P=0.99). Within 3 days after the start of supplementation, plasma concentrations of 18:2n-6 increased (P<0.001) for cattle fed SOY compared with CON or FLX, whereas flax-fed cattle did not exhibit an increase (P=0.02) until day 15 of supplementation over that of CON. Plasma concentrations for 18:3n-3 was greater (P<0.013) for FLX than both CON and SOY by day 12. Feeding flaxseed tended to (P=0.07) increase and increased (P=0.01) plasma concentrations of 20:4n-6 by day 18 over CON and SOY, respectively. Overall, treatment did not affect serum concentration of progesterone (P=0.18) or prostaglandin F metabolite (P=0.89). However, day after breeding had an effect on serum progesterone (P=0.01) with day 16 after timed AI being lower compared with other days. Feeding oilseeds during the time of estrous synchronization will not only increase the energy density of the diet but will provide key fatty acids around the time of maternal recognition of pregnancy.

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.

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.

In the present study, the effect of flax hulls with or without flax oil bypassing the rumen on the expression of lipogenic genes in the mammary tissue of dairy cows was investigated. A total of eight dairy cows were used in a replicated 4 × 4 Latin square design. There were four periods of 21 d each and four treatments: control diet with no flax hulls (CONT); diet with 9·88 % flax hulls in the DM (HULL); control diet with 500 g flax oil/d infused in the abomasum (COFO); diet with 9·88 % flax hulls in the DM and 500 g flax oil/d infused in the abomasum (HUFO). A higher mRNA abundance of sterol regulatory element binding transcription factor, fatty acid (FA) synthase, lipoprotein lipase (LPL), PPARγ1, stearoyl-CoA desaturase (SCD) and acetyl-coenzyme A carboxylase-α was observed in cows fed HULL than in those fed CONT, and HUFO had the opposite effect. Compared with CONT, COFO and HUFO lowered the mRNA abundance of SCD, which may explain the lower proportions of MUFA in milk fat with flax oil infusion. The mRNA abundance of LPL in mammary tissue and proportions of long-chain FA in milk fat were higher in cows fed COFO than in those fed CONT. The highest proportions of trans FA were observed when cows were fed HULL. The present study demonstrates that flax hulls with or without flax oil infusion in the abomasum can affect the expression of lipogenic genes in the mammary tissue of dairy cows, which may contribute to the improvement of milk FA profile.

The effects of adding flaxseed or fish oil to the diet of dairy cows on the chemical and physical profile of Mozzarella cheese production were studied. The experiment involved 24 Friesian cows, divided into 3 groups accordingly fat supplementation: basal diet (CT), diet supplemented with flaxseed (FS) or fish oil (FO). Mozzarella cheeses were manufactured from bulk milk of each group. Bulk milk was analysed for chemical composition and renneting parameters. Mozzarella cheeses were analysed for chemical composition, fatty acid profile, and textural properties. Results suggest that Mozzarella cheese from cows receiving flaxseed supplementation showed a decrease in saturated fatty acids (SFA), an increase in monounsaturated fatty acids (MUFA), and in polyunsaturated fatty acids (PUFA) compared with control Mozzarella cheese. The increased dietary intake of C18:3 in flaxseed supplemented cows resulted in increased levels of trans-11 C18:1, and of CLA cis-9 trans-11 C18:2, and in low Atherogenic and Trombogenic Indexes. FO Mozzarella cheese showed compositional and textural properties quite similar to CT Mozzarella cheese; however, increased levels of n-3 polyunsaturated fatty acids in FO Mozzarella were found.

Ruminal microbiota plays an important role in the conversion of plant lignans into mammalian lignans. The main mammalian lignan present in the milk of dairy cows fed flax products is enterolactone (EL). The objectives of the present study were to investigate the effects of abomasal infusion of flax oil on the metabolism of flax lignans and concentrations of EL in biological fluids of dairy cows. A total of six rumen-cannulated dairy cows were assigned within a 2 × 3 factorial arrangement of six treatments utilising flax hulls (0 and 15·9 % of DM) and abomasal infusion of flax oil (0, 250 and 500 g/d). There were six periods of 21 d each. Samples were collected during the last 7 d of each period and subjected to chemical analysis. Flax hull supplementation increased concentrations of EL in ruminal fluid, plasma, urine and milk, while flax oil infusion had no effect. Post-feeding, β-glucuronidase activity in the ruminal fluid of cows infused with 250 g flax oil was significantly lower for cows fed hulls than for those fed the control diet. The present study demonstrated that the presence of a rich source of n-3 fatty acids such as flax oil in the small intestine does not interfere with the absorption of the mammalian lignan EL and that lower ruminal β-glucuronidase activity had no effect on the conversion of flax lignans into EL in the rumen of dairy cows.