Effect of extruded linseeds alone or in combination with fish oil on intake,milk production,plasma metabolite concentrations and milk fatty acid composition in lactating goats

Based on the potential benefits for long-term human health, there is interest in developing sustainable nutritional strategies for lowering medium-chain saturated fatty acids (FA) and increasing specific unsaturated FA in ruminant milk. Dietary supplements of extruded linseeds (EL), fish oil (FO) or a mixture of EL and FO increase cis-9,trans-11 CLA and long-chain n-3 polyunsaturated FA in bovine milk. Supplements of FO cause milk fat depression in lactating cows, but information for dairy goats is limited. A total of 14 Alpine goats were used in a replicated 3×3 Latin square with 28-days experimental periods to examine the effects of EL alone or in combination with FO on animal performance, milk fat synthesis and milk FA composition. Treatments comprised diets based on natural grassland hay supplemented with no additional oil (control), 530 of EL or 340 g/day of EL and 39 g/day of FO (ELFO). Compared with the control, ELFO tended (P=0.08) to lower milk fat yield, whereas EL increased (P<0.01) milk fat content and yield (15% and 10%, respectively). Relative to EL, ELFO decreased (P<0.01) milk fat content and yield (19% and 17%, respectively). Relative to the control and ELFO, EL decreased (P<0.05) milk 10:0 to 16:0 and odd- and branched-chain FA content and increased 18:0, cis-18:1, trans-13 18:1 (and their corresponding ∆-9 (desaturase products), trans-12,cis-14 CLA, cis-13,trans-15 CLA, cis-12,trans-14 CLA and trans-11,cis-13 CLA and 18:3n-3 concentrations. ELFO was more effective for enriching (P<0.05) milk cis-9, trans-11 CLA and trans-11 18:1 concentrations (up to 5.4- and 7.1-fold compared with the control) than EL (up to 1.7- and 2.5-fold increases). Furthermore, ELFO resulted in a substantial increase in milk trans-10 18:1 concentration (5.4% total FA), with considerable variation between individual animals. Relative to the control and EL, milk fat responses to ELFO were characterized by increases (P<0.05) in milk trans-16:1 (Δ9 to 11), trans-18:1 (Δ6 to 11), trans-18:2, CLA (cis-9,trans-11, trans-9,cis-11, trans-8,trans-10 and trans-7,trans-9) and 20- and 22-carbon FA concentrations. Overall, EL resulted in a relatively high cis-9 18:1 concentration and an increase in the 18:3n-3/18:2n-6 ratio, whereas combining EL and FO resulted in substantial increases in trans-FA, marginal enrichment in 20:5n-3 and 22:6n-3 and lower 16:0 concentration changes associated with a decrease in milk fat content. In conclusion, data provide further evidence of differential mammary lipogenic responses to diet in the goat compared with the cow and sheep.     

Effect of replacing calcium salts of palm oil distillate with incremental amounts of conventional or high oleic acid milled rapeseed on milk fatty acid composition in cows fed maize silage-based diets

Based on potential benefits to human health, there is increasing interest in altering the composition of ruminant-derived foods. Including rapeseeds in the dairy cow diet is an effective strategy for replacing medium-chain saturated fatty acids (SFA) with cis-monounsaturated fatty acids (MUFA) in bovine milk, but there is limited information on the optimum level of supplementation. Decreases in SFA due to plant oils are also accompanied by increases in milk trans fatty acid (FA) content and it is possible that high oleic acid rapeseeds may result in a higher enrichment of cis-9 18:1 and lower increases in trans FAs in milk compared with conventional varieties. Seven multiparous lactating Holstein-Friesian cows were allocated to one of seven treatments in an incomplete Latin square design with five 28-day experimental periods, to evaluate the effect of replacing calcium salts of palm oil distillate (CPO; 41 g/kg diet dry matter, DM) with 128, 168 or 207 g/kg diet DM of conventional (COR) or a high oleic acid (HOR) rapeseed fed as a supplement milled with wheat. Rapeseed variety and inclusion level had no effect (P > 0.05) on DM intake, milk yield and composition. Both rapeseed varieties decreased linearly (P < 0.001) milk fat SFA content, which was partially compensated for by a linear increase (P < 0.001) in cis-9 18:1 concentration. Reductions in milk SFA were also associated with increases (P < 0.05) in trans 18:1 and total trans FA content, with no difference (P > 0.05) between rapeseed varieties. Replacing CPO in the diet with milled rapeseeds had no effect (P > 0.05) on total milk conjugated linoleic acid (CLA) concentration. Relative to a COR, inclusion of a high oleic acid variant in the diet increased (P = 0.01) the ratio of trans-MUFA : trans-polyunsaturated fatty acids in milk that may have implications with respect to cardiovascular disease risk in humans. In conclusion, data indicated that replacing CPO with milled rapeseeds at levels up to 1150 g oil/day could be used as a nutritional strategy to lower milk SFA content without inducing adverse effects on DM intake and milk production. HOR reduced milk fat SFA content to a greater extent than a conventional variety, but did not minimise associated increases in trans FA concentrations. However, the high oleic acid variant did alter the relative abundance of specific trans 18:1, CLA and trans 18:2 isomers compared with conventional rapeseeds.     

Effect of replacing calcium salts of palm oil distillate with rapeseed oil, milled or whole rapeseeds on milk fatty-acid composition in cows fed maize silage-based diets

Inclusion of rapeseed feeds in dairy cow diets has the potential to reduce milk fat saturated fatty acid (SFA) and increase cis-monounsaturated fatty acid (cis-MUFA) content, but effectiveness may depend on the form in which the rapeseed is presented. Four mid-lactation Holstein dairy cows were allocated to four maize silage-based dietary treatments according to a 4 × 4 Latin Square design, with 28-day experimental periods. Treatments consisted of a control diet (C) containing 49 g/kg dry matter (DM) of calcium salts of palm oil distillate (CPO), or 49 g/kg DM of oil supplied as whole rapeseeds (WR), rapeseeds milled with wheat (MR) or rapeseed oil (RO). Replacing CPO with rapeseed feeds had no effect (P > 0.05) on milk fat and protein content, while milk yields were higher (P < 0.05) for RO and MR compared with WR (37.1, 38.1 and 34.3 kg/day, respectively). Substituting CPO with RO or MR reduced (P < 0.05) milk fat total SFA content (69.6, 55.6, 71.7 and 61.5 g/100 g fatty acids for C, RO, WR and MR, respectively) and enhanced (P < 0.05) milk cis-9 18:1 MUFA concentrations (corresponding values 18.6, 24.3, 17.0 and 23.0 g/100 g fatty acids) compared with C and WR. Treatments RO and MR also increased (P < 0.05) milk trans-MUFA content (4.4, 6.8, 10.5 g/100 g fatty acids, C, MR and RO, respectively). A lack of significant changes in milk fat composition when replacing CPO with WR suggests limited bioavailability of fatty acids in intact rapeseeds. In conclusion, replacing a commercial palm oil-based fat supplement in the diet with milled rapeseeds or rapeseed oil represented an effective strategy to alter milk fatty acid composition with the potential to improve human health. Inclusion of processed rapeseeds offered a good compromise for reducing milk SFA and increasing cis-MUFA, whilst minimising milk trans-MUFA and negative effects on animal performance.     

Influence of pumpkin seed cake and extruded linseed on milk production and milk fatty acid profile in Alpine goats

The aim was to determine the effect of substituting pumpkin seed cake (PSC) or extruded linseed (ELS) for soya bean meal in goats’ diets on milk yield, milk composition and fatty acids profile of milk fat. In total, 28 dairy goats were divided into three groups. They were fed with concentrate mixtures containing soya bean meal (Control; n=9), ELS (n=10) or PSC (n=9) as main protein sources in the trial lasting 75 days. Addition of ELS or PSC did not influence milk yield and milk gross composition in contrast to fatty acid profile compared with Control. Supplementation of ELS resulted in greater branched-chain fatty acids (BCFA) and total n-3 fatty acids compared with Control and PSC (P<0.05). Total n-3 fatty acids were accompanied by increased α-linolenic acid (ALA, C18:3n-3; 0.56 g/100 g fatty acids) and EPA (C20:5n-3; 0.12 g/100 g fatty acids) proportions in milk of the ELS group. In contrast, ELS and PSC resulted in lower linoleic acid (LA, C18:2n-6; 2.10 and 2.28 g/100 g fatty acids, respectively) proportions compared with Control (2.80 g/100 g fatty acids; P<0.05). Abovementioned resulted in lower LA/ALA ratio (3.81 v. 7.44 or 6.92, respectively; P<0.05) with supplementation of ELS compared with Control or PSC. The PSC diet decreased total n-6 fatty acids compared with the Control (2.96 v. 3.54 g/100 g fatty acids, P<0.05). Oleic acid (c9-C18:1), CLA (c9,t11-18:2) and t10-,t11-C18:1 did not differ between treatments (P⩾0.08), although stearic acid (C18:0) increased in ELS diets compared with Control (12.7 v. 10.2 g/100 g fatty acids, P<0.05). Partially substituted soya bean meal with ELS in hay-based diets may increase beneficial n-3 fatty acids and BCFA accompanied by lowering LA/ALA ratio and increased C18:0. Pumpkin seed cake completely substituted soya bean meal in the diet of dairy goats without any decrease in milk production or sharp changes in fatty acid profile that may have a commercial or a human health relevancy.     

Effect of oilseed type on milk fatty acid composition of individual cows,and also bulk tank milk fatty acid composition from commercial farms

Supplementing dairy cow diets with oilseed preparations has been shown to replace milk saturated fatty acids (SFA) with mono- and/or polyunsaturated fatty acids (MUFA, PUFA), which may reduce risk factors associated with cardio-metabolic diseases in humans consuming milk and dairy products. Previous studies demonstrating this are largely detailed, highly controlled experiments involving small numbers of animals, but in order to transfer this feeding strategy to commercial situations further studies are required involving whole herds varying in management practices. In experiment 1, three oilseed supplements (extruded linseed (EL), calcium salts of palm and linseed oil (CPLO) and milled rapeseed (MR)) were included in grass silage-based diets formulated to provide cows with ~350 g oil/day, and compared with a negative control (Control) diet containing no supplemental fat, and a positive control diet containing 350 g/cow per day oil as calcium salt of palm oil distillate (CPO). Diets were fed for 28-day periods in a 5×4 Latin Square design, and milk production, composition and fatty acid (FA) profile were analysed at the end of each period. Compared with Control, all lipid supplemented diets decreased milk fat SFA concentration by an average of 3.5 g/100 g FA, by replacement with both cis- and trans-MUFA/PUFA. Compared with CPO, only CPLO and MR resulted in lower milk SFA concentrations. In experiment 2, 24 commercial dairy farms (average herd size±SEM 191±19.3) from the south west of the United Kingdom were recruited and for a 1 month period asked to supplement their herd diets with either CPO, EL, CPLO or MR at the same inclusion level as the first study. Bulk tank milk was analysed weekly to determine FA concentration by Fourier Transform mid-IR spectroscopy prediction. After 4 weeks, EL, CPLO and MR all decreased herd milk SFA and increased MUFA to a similar extent (average −3.4 and +2.4 g/100 g FA, respectively) when compared with CPO. Differing responses observed between experiments 1 and 2 may be due in part to variations in farm management conditions (including basal diet) in experiment 2. This study demonstrates the importance of applying experimental research into commercial practice where variations in background conditions can augment different effects to those obtained under controlled conditions.     

Influence of an increase in diet structure on milk conjugated linoleic acid content of cows fed extruded linseed

This experiment studied the effect of a modest difference in diet structure value (SV) on milk conjugated linoleic acid (CLA) contents of cows fed diets supplemented with extruded linseed, in situations where the diets provided enough SV and therefore did not induce milk fat depression. Six lactating Holstein cows were used in a crossover design with two treatments ('SV 1.50' and 'SV 1.73') and two periods of 21 days. The 'SV 1.50' diet contained 59% maize silage, 13% soya bean meal, 13% sugar beet pulp and 14% Nutex Compact (containing 56% extruded linseed) (dry matter (DM) basis) and was offered as a restricted total mixed ration. For the 'SV 1.73' diet, 8% wheat straw (DM basis) was added to the 'SV 1.50' diet as an additional structure source. The two diets had a forage-to-concentrate ratio of 59 : 41 and 62 : 38. The inclusion of straw in the diet resulted in an additional intake of NDF (+1110 g/day), which accounted for 90% of the additional intake of OM, whereas additional intakes of the other nutrients were minor. Milk yield and composition did not differ among treatments. The inclusion of straw in the diet did not affect the milk levels of t10-18:1, 18:2n-6, c9-16:1, c9-18:1, c11-18:1, 6:0, 8:0, 20:4 and 20:5. It decreased the milk levels of c9,t11-CLA (2.13% v. 3.03% of fatty acids (FA) reported, P < 0.001), t11-18:1 (4.99% v. 7.10% of FA reported, P < 0.001), 18:3n-3, t9-16:1 and t9-18:1, while it increased the milk levels of 6:0-14:0 (20.90% v. 19.69% of FA reported, P < 0.01), 16:0 (26.55% v. 25.25% of FA reported, P < 0.01), 18:0 (13.54% v. 12.59% of FA reported, P < 0.001), 17:0, 20:0 and 22:5. Regarding the ratio between FA, the inclusion of straw increased the 18:0/total C18 FA ratio (37.74% v. 32.07%, P < 0.001), whereas it decreased the total trans-C18 FA/total C18 FA ratio (15.46% v. 20.34%, P < 0.001), the t11-18:1/total C18 FA ratio (13.70% v. 17.95%, P < 0.01) and the c9,t11-CLA/total C18 FA ratio (5.82% v. 7.64%, P < 0.001). We conclude from this experiment that even a modest increase in SV to a diet supplemented with extruded linseed, yet already providing enough SV, alters the rumen lipid metabolism and, hence, CLA levels in milk fat.     

Influence of feeding whole sunflower seed and extruded linseed on production of dairy cows,rumen and plasma constituents,and fatty acid composition of milk

Holstein cows were fed total mixed rations (TMR) supplemented with protected palm fat (PPF), whole sunflower seed (WSS) or extruded linseed (ELS) for 100 days. Percentage of dietary crude fat was 5.3, 5.1 and 5.1, respectively. Diet had no (p > 0.05) effect on feed intake, milk yield or milk protein content. Percentage of milk fat and yield of fat – corrected milk were significantly increased when diets were supplemented with WSS and ELS. Feeding PPF resulted in the lowest (p < 0.05) ruminal concentration of volatile fatty acids. No significant dietary effect on plasma characteristics was observed. Concentration of polyunsaturated fatty acids (PUFA) was higher (p < 0.05), and PUFA n-6/n-3 ratio lower (p < 0.05), in the milk fat from cows fed ELS compared to WSS. Supplementation of TMR with oilseeds compared to PPF increased the content of CLA in milk fat (p < 0.005) and decreased its atherogenicity, primarily due to a significant reduction of palmitic acid concentration. Both oilseeds significantly improved the spreadability index of manufactured butter. ELS, but not WSS, increased the susceptibility of milk fat to oxidation (p < 0.05). It can be concluded that feeding of oilseeds to dairy cows improved nutritional quality of milk fat, with supplementation with ELS producing an even more desirable milk fatty acid profile than WSS supplementation.     

Effect of extruded linseed supplementation on blood metabolic profile and milk performance of Saanen goats

This study assessed the effects of dietary supplementation with extruded linseed on milk yield and composition, milk fatty acid (FA) profile and renal and hepatic metabolism of grazing goats in mid-lactation. Forty Saanen goats were divided into two isoproductive groups: one group was fed the control diet (CON) composed of hay and pelleted concentrate and the other group was supplemented with additional 180 g/day of extruded linseed (LIN; dry matter basis), which supplied 70 g/day of fat per head for 9 weeks. Animals grazed on pasture for ∼3 h/day after the first of the 2 daily milkings. Milk samples were collected weekly and analyzed for fat, protein, lactose, milk urea nitrogen (MUN) and somatic cell count. Blood samples were collected every 2 weeks and analyzed for total bilirubin, creatinine, aspartate transaminase (AST), alanine transaminase (ALT), gamma glutamyl transpeptidase, alkaline phosphatase, total protein and urea nitrogen. Milk yield was higher in the LIN than in the CON group (2369 v. 2052 g/day). LIN group had higher milk fat (37.7 v. 33.4 g/kg) and protein (30.7 v. 29.1 g/kg) concentration and lower MUN (35.0 v. 43.3 mg/dl) than CON group. Goats fed LIN had greater proportions of 18:1 trans11, 18:2 cis9trans11 and total polyunsatured fatty acids n-3 in milk fat, because of higher 18:3n-3 and 20:5n-3 FA, and lower proportions of short- and medium-chain FAs than goats fed CON. All kidney and liver function biomarkers in serum did not differ between dietary groups, except for AST and ALT, which tended to differ. Extruded linseed supplementation to grazing mid-lactating goats for 2 months can enhance the milk performance and nutritional profile of milk lipids, without altering the general hepatic and renal metabolism.     

Effect of replacing grass silage with maize silage in the diet on bovine milk fatty acid composition

Even though extensive research has examined the role of nutrition on milk fat composition, there is less information on the impact of forages on milk fatty acid (FA) composition. In the current study, the effect of replacing grass silage (GS) with maize silage (MS) as part of a total mixed ration on animal performance and milk FA composition was examined using eight multiparous mid-lactation cows in a replicated 4 × 4 Latin square with 28-day experimental periods. Four treatments comprised the stepwise replacement of GS with MS (0, 160, 334 and 500 g/kg dry matter (DM)) in diets containing a 54 : 46 forage : concentrate ratio on a DM basis. Replacing GS with MS increased (P < 0.001) the DM intake, milk yield and milk protein content. Incremental replacement of GS with MS in the diet enhanced linearly (P < 0.001) the proportions of 6:0-14:0, decreased (P < 0.01) the 16:0 concentrations, but had no effect on the total milk fat saturated fatty acid content. Inclusion of MS altered the distribution of trans-18:1 isomers and enhanced (P < 0.05) total trans monounsaturated fatty acid and total conjugated linoleic acid content. Milk total n-3 polyunsaturated fatty acid (PUFA) content decreased with higher amounts of MS in the diet and n-6 PUFA concentration increased, leading to an elevated n-6 : n-3 PUFA ratio. Despite some beneficial changes associated with the replacement of GS with MS, the overall effects on milk FA composition would not be expected to substantially improve long-term human health. However, the role of forages on milk fat composition must also be balanced against the increases in total milk and protein yield on diets containing higher proportions of MS.     

Stearoyl-CoA desaturase 1 genotype and stage of lactation influences milk fatty acid composition of Canadian Holstein cows

Single nucleotide polymorphisms in the coding region of the bovine stearoyl-CoA desaturase 1 gene have been predicted to result in p.293A (alanine at amino acid 293) and p.293V (valine at amino acid 293) alleles at the stearoyl-CoA desaturase1 locus. The objectives of this study were to evaluate the extent to which genotypes at the stearoyl-CoA desaturase 1 locus and stage of lactation influence milk fatty acid composition in Canadian Holstein cows. Cows with the p.293AA genotype had higher C10 index, C12 index and C14 index and higher concentrations of C10:1 (10 carbon fatty acid with one double bond), C12:1 (12 carbon fatty acid with one double bond) and myristoleic acid (C14:1) compared with the p.293AV or p.293VV cows. Cows had higher C18 index and total index, and lower C10 index, C12 index, C14 index and CLA index during early lactation compared with the subsequent lactation stages. Early lactation was also characterized by higher concentrations of oleic acid (C18:1 cis -9), vaccenic acid (C18:1 trans -11), linoleic acid (C18:2), monounsaturated fatty acids and total polyunsaturated fatty acids, and lower concentrations of capric acid (C10:0), C10:1, lauric acid (C12:0), C12:1, myristic acid (C14:0), myristoleic acid (C14:1), palmitic acid (C16:0) and total saturated fatty acids compared with the subsequent lactation stages. Neither the stearoyl-CoA desaturase 1 genotype nor the stage of lactation had an influence on conjugated linoleic acid concentrations in milk.     

Conjugated linolenic acid (CLnA), conjugated linoleic acid (CLA) and other biohydrogenation intermediates in plasma and milk fat of cows fed raw or extruded linseed

Thirty lactating dairy cows were used in a 3 × 3 Latin-square design to investigate the effects of a raw or extruded blend of linseed and wheat bran (70:30) on plasma and milk fatty-acids (FA). Linseed diets, containing 16.6% linseed blend on a dry-matter basis, decreased milk yield and protein percentage. They decreased the proportions of FA with less than 18 carbons in plasma and milk and resulted in cis-9, cis-12, cis-15 18:3 proportions that were more than three and four times higher in plasma and milk, respectively, whereas cis-9, cis-12 18:2 proportions were decreased by 10-15%. The cis-9, trans-11, cis-15 18:3 isomer of conjugated linolenic acid was not detected in the milk of control cows, but was over 0.15% of total FA in the milk fat of linseed-supplemented cows. Similarly, linseed increased plasma and milk proportions of all biohydrogenation (BH) intermediates in plasma and milk, including the main isomer of conjugated linoleic acid cis-9, trans-11 18:2, except trans-4 18:1 and cis-11, trans-15 18:2 in plasma lipids. In milk fat, compared with raw linseed, extruded linseed further reduced 6:0-16:0 even-chain FA, did not significantly affect the proportions of 18:0, cis-9 18:1 and cis-9, cis-12 18:2, tended to increase cis-9, cis-12, cis-15 18:3, and resulted in an additional increase in the proportions of most BH intermediates. It was concluded that linseed addition can improve the proportion of conjugated linoleic and linolenic acids, and that extrusion further increases the proportions of intermediates of ruminal BH in milk fat.     

Effect of linseed supplementation of the gestation and lactation diets of dairy ewes on the growth performance and the intramuscular fatty acid composition of their lambs

In this study, we investigated the effects of maternal gestation and/or lactation diets supplemented with extruded linseed (rich in 18:3n-3) on growth performance and long-chain polyunsaturated faaty acid (PUFA) accumulation in muscle tissues of suckling lambs. A total of 36 dairy ewes were fed a control diet (CON) and a diet containing linseed (LIN) during the last 8 weeks of gestation and/or the first 4 weeks of lactation. The four dietary treatments consisted of the following gestation/lactation feeding treatments: CON/CON, CON/LIN, LIN/LIN or LIN/CON. The lambs born from ewes fed the aforementioned diets were reared exclusively on milk and were slaughtered at 4 weeks of age. Profiles of ewes’ milk fatty acids and that of intramuscular fat (IMF) of leg muscles from lambs were determined. Compared with the CON/CON, LIN/CON offspring tended to grow slower and to have reduced cold carcass weights. Moreover, the LIN supplementation only in the prepartum period (LIN/CON) resulted in greater PUFAn-3 accumulation in the IMF compared with the CON/CON offspring due to increased 20:5n-3 (1.20 v. 0.64 mg/100 mg of total FA), 22:5n-3 (1.91 v. 1.46;) and 22:6n-3 (1.25 v. 0.89) contents, respectively. Compared with the CON/CON diet, providing LIN only during lactation (CON/LIN) caused a greater PUFAn-3 content in the IMF mainly due to a greater 18:3n-3 (1.79 v. 0.75 mg/100 g total FA) concentration. Continuous PUFAn-3 exposure, both via the maternal gestation and lactation diet, had no additive effects on PUFAn-3 accumulation in tissues. The results suggest that linseed, as an 18:3n-3 source, seems to be more efficient in increasing long-chain PUFAn-3 in fetal than in suckling lamb tissues.     

Differential effects of oilseed supplements on methane production and milk fatty acid concentrations in dairy cows

It is known that supplementing dairy cow diets with full-fat oilseeds can be used as a strategy to mitigate methane emissions, through their action on rumen fermentation. However, direct comparisons of the effect of different oil sources are very few, as are studies implementing supplementation levels that reflect what is commonly fed on commercial farms. The objective was to investigate the effect of feeding different forms of supplemental plant oils on both methane emissions and milk fatty acid (FA) profile. Four multiparous, Holstein-Friesian cows in mid-lactation were randomly allocated to one of four treatment diets in a 4×4 Latin square design with 28-day periods. Diets were fed as a total mixed ration with a 50 : 50 forage : concentrate ratio (dry matter (DM) basis) with the forage consisting of 75 : 25 maize silage : grass silage (DM). Dietary treatments were a control diet containing no supplemental fat, and three treatment diets containing extruded linseed (EL), calcium salts of palm and linseed oil (CPLO) or milled rapeseed (MR) formulated to provide each cow with an estimated 500 g additional oil/day (22 g oil/kg diet DM). Dry matter intake (DMI), milk yield, milk composition and methane production were measured at the end of each experimental period when cows were housed in respiration chambers for 4 days. There was no effect of treatment diet on DMI or milk protein or lactose concentration, but oilseed-based supplements increased milk yield compared with the control diet and milk fat concentration relative to control was reduced by 4 g/kg by supplemental EL. Feeding CPLO reduced methane production, and both linseed-based supplements decreased methane yield (by 1.8 l/kg DMI) and intensity (by 2.7 l/kg milk yield) compared with the control diet, but feeding MR had no effect on methane emission. All the fat supplements decreased milk total saturated fatty acid (SFA) concentration compared with the control, and SFA were replaced with mainly cis-9 18:1 but also trans FA (and in the case of EL and CPLO there were increases in polyunsaturated FA concentration). Supplementing dairy cow diets with these oilseed-based preparations affected milk FA profile and increased milk yield. However, only the linseed-based supplements reduced methane production, yield or intensity, whereas feeding MR had no effect.     

Relationships between methane emission of Holstein Friesian dairy cows and fatty acids,volatile metabolites and non-volatile metabolites in milk

This study investigated the relationships between methane (CH₄) emission and fatty acids, volatile metabolites (V) and non-volatile metabolites (NV) in milk of dairy cows. Data from an experiment with 32 multiparous dairy cows and four diets were used. All diets had a roughage : concentrate ratio of 80 : 20 based on dry matter (DM). Roughage consisted of either 1000 g/kg DM grass silage (GS), 1000 g/kg DM maize silage (MS), or a mixture of both silages (667 g/kg DM GS and 333 g/kg DM MS; 333 g/kg DM GS and 677 g/kg DM MS). Methane emission was measured in climate respiration chambers and expressed as production (g/day), yield (g/kg dry matter intake; DMI) and intensity (g/kg fat- and protein-corrected milk; FPCM). Milk was sampled during the same days and analysed for fatty acids by gas chromatography, for V by gas chromatography–mass spectrometry, and for NV by nuclear magnetic resonance. Several models were obtained using a stepwise selection of (1) milk fatty acids (MFA), V or NV alone, and (2) the combination of MFA, V and NV, based on the minimum Akaike’s information criterion statistic. Dry matter intake was 16.8±1.23 kg/day, FPCM yield was 25.0±3.14 kg/day, CH₄ production was 406±37.0 g/day, CH₄ yield was 24.1±1.87 g/kg DMI and CH₄ intensity was 16.4±1.91 g/kg FPCM. The observed CH₄ emissions were compared with the CH₄ emissions predicted by the obtained models, based on concordance correlation coefficient (CCC) analysis. The best models with MFA alone predicted CH₄ production, yield and intensity with a CCC of 0.80, 0.71 and 0.69, respectively. The best models combining the three types of metabolites included MFA and NV for CH₄ production and CH₄ yield, whereas for CH₄ intensity MFA, NV and V were all included. These models predicted CH₄ production, yield and intensity better with a higher CCC of 0.92, 0.78 and 0.93, respectively, and with increased accuracy (C_b) and precision (r). The results indicate that MFA alone have moderate to good potential to estimate CH₄ emission, and furthermore that including V (CH₄ intensity only) and NV increases the CH₄ emission prediction potential. This holds particularly for the prediction model for CH₄ intensity.     

Rice bran lipase catalyzed esterification of palm oil fatty acid distillate and glycerol in organic solvent

Rice bran lipase (RBL) was delipidated to enhance its stability in organic solvent and its esterification activity at elevated temperature. The esterification activity of delipidated RBL increased as temperature was increased from 45 to 65°C. The esterification activity of delipidated RBL at 65°C was about 14 times greater than that of the non-delipidated RBL. As temperature was further increased to 75°C, the non-delipidated RBL lost all esterification activity, whereas the delipidated RBL retained approximately 48% of its esterilication activity. The delipidated RBL maintained a relative esterification activity greater than 80% after 16 h of incubation in hexane, whereas the non-delipidated RBL maintained a relative esterification activity of only 50%. A method for production of acylglycerol using delipidated RBL to esterify palm oil fatty acid distillate (PFAD) with glycerol in hexane was successfully developed. The effects of reaction temperatures and type of water removal agents (silica gel and molecular sieve) on the degree of esterification were also examined. A 4 h reaction at 65°C, catalyzed by delipidated RBL and using silica gel as the water removal agent resulted in 53.8% esterification. Thin layer chromatography analysis suggested that the esterified product was primarily comprised of mono-and di-acylglycerols.     

Effect of FASN gene on milk yield and milk composition in the Chinese Holstein dairy population

Fatty acid synthase (FASN) is a multifunctional protein that catalyzes de novo synthesis of fatty acids in cells. It plays a key role in the lipid biosynthesis as well as in the general metabolism of all living animals. We herein investigated polymorphisms of FASN. As a result, six single nucleotide polymorphisms (SNPs) were found and then genotyped in 752 Chinese Holstein cows. It was found that g.17924A>G was non‐synonymous, g.13965 C>T, g.16907 T>C and g.18663T>C were synonymous mutations and two other two SNPs, g.8948 C>T (ss491228481) and g.14439T>C (rs133498277), were in intronic sequences of the gene. All such identified SNPs were found to be associated with milk yield and composition traits (P = 0.0441 to <0.0001). Significant additive and allele substitution effects were observed for three yield traits at all six loci as well (P < 0.05 to <0.01). Complete linkage disequilibrium among the five SNPs, with the exception of g.8948 C>T, was observed.     

Genetic polymorphisms at candidate genes affecting fat content and fatty acid composition in Modicana cows: effects on milk production traits in different feeding systems

Feeding greatly affects milk yield and composition. The research is highlighting the potential of genetic polymorphism at some loci to affect milk yield and quality traits. These loci can be up/down regulated depending on the production environment; therefore, we hypothesized that milk yield and composition could differ when cows with different genotype at SCD, DGAT1 and ABCG2 loci are reared in different feeding systems. The polymorphisms of SCD, DGAT1 and ABCG2 genes were investigated in Modicana breed. In all, three polymorphic sites, responsible for the genetic variation of quantitative trait loci and therefore defined quantitative trait nucleotides, were genotyped: the transition g.10329C>T in 5^th exon determines a substitution p.A293V in the SCD, the dinucleotide mutation g.10433-10434AA>GC in 8^th exon responsible for p.K232A substitution in the DGAT1 and the transition g.62569A>C in the 14^th exon responsible for p.Y581S substitution in the ABCG2 gene. In the sample of 165 Modicana cows, SCD and DGAT1 genes resulted polymorphic; the alleles g.10329T and g.10433-10434GC were the most frequent in SCD and DGAT1 (0.73 and 0.91) respectively, whereas ABCG2 locus was monomorphic for allele A (p.581Y). Sequencing analysis was carried out on 14 samples with different genotypes to confirm the results of the PCR-RFLP protocols. Based on the genotypes at SCD locus, 47 Modicana cows were selected for the nutritional trial: 24 cows in a semi-intensive farm, with 2 h/day grazing on natural pasture, and 23 cows in an extensive farm, with 8 h/day grazing on natural pasture. Monthly, milk yield and composition were evaluated and individual milk samples were analyzed for fatty acids composition by gas chromatography. No differences in milk yield, fat, protein, lactose, casein and urea were associated to SCD genotype. Feeding systems affected milk yield and composition. No significant genotype×feeding system interaction was observed for milk yield and composition. Fatty acids composition was significantly affected only by the feeding system. Significant interactions were found between SCD genotype and feeding system for six fatty acids: 4:0, 6:0, 8:0, 10:0, 12:0 and t11 18:1. We concluded that the feeding system was the factor that mostly affected milk production and composition; moreover, our results do not confirm what reported in literature as regard the effect of the SCD polymorphism on milk fatty acid composition. The high amount of pasture seemed to have resized the SCD polymorphism effects because of the different fatty acids composition of the diet.     

Frequent moving of grazing dairy cows to new paddocks increases the variability of milk fatty acid composition

The aim of this work was to investigate the variations of milk fatty acid (FA) composition because of changing paddocks in two different rotational grazing systems. A total of nine Holstein and nine Montbéliarde cows were divided into two equivalent groups according to milk yield, fat and protein contents and calving date, and were allocated to the following two grazing systems: a long duration (LD; 17 days) of paddock utilisation on a heterogeneous pasture and a medium duration (MD) of paddock utilisation (7 to 10 days) on a more intensively managed pasture. The MD cows were supplemented with 4 kg of concentrate/cow per day. Grazing selection was characterised through direct observations and simulated bites, collected at the beginning and at the end of the utilisation of two subsequent MD paddocks, and at the same dates for the LD system. Individual milks were sampled the first 3 days and the last 2 days of grazing on each MD paddock, and simultaneously also for the LD system. Changes in milk FA composition at the beginning of each paddock utilisation were highly affected by the herbage characteristics. Abrupt changes in MD milk FA composition were observed 1 day after the cows were moved to a new paddock. The MD cows grazed by layers from the bottom layers of the previous paddock to the top layers of the subsequent new paddock, resulting in bites with high organic matter digestibility (OMD) value and CP content and a low fibre content at the beginning of each paddock utilisation. These changes could induce significant day-to-day variations of the milk FA composition. The milk fat proportions of 16:0, saturated FA and branched-chain FA decreased, whereas proportions of de novo-synthesised FA, 18:0, c9-18:1 and 18:2n-6 increased at paddock change. During LD plot utilisation, the heterogeneity of the vegetation allowed the cows to select vegetative patches with higher proportion of leaves, CP content, OMD value and the lowest fibre content. These small changes in CP, NDF and ADF contents of LD herbage and in OMD values, from the beginning to the end of the experiment, could minimally modify the ruminal ecosystem, production of precursors of de novo-synthesised FA and ruminal biohydrogenation, and could induce only small day-to-day variations in the milk FA composition.     

Effect of a linseed diet on lipogenesis, fatty acid composition and stearoyl-CoA-desaturase in rabbits

The aim of the study was to examine the effect of a linseed diet on meat quality and on lipogenesis in rabbits. Twelve rabbits were fed a control or a linseed diet. There was no diet effect on growth, food consumption, carcass characteristics and meat ultimate pH and colour. Feeding the linseed diet increased the n-3 polyunsaturated fatty acids (PUFA) levels in perirenal and interscapular fats, in the Longissimus dorsi muscle and in the liver. The linseed diet produced lower linoleic acid/α-linolenic acid ratios in adipose tissues and in the Longissimus dorsi muscle, but not in the liver. Diet did not affect lipogenic enzyme activities in the Longissimus dorsi muscle, whereas the linseed diet decreased the lipogenic potential in perirenal and interscapular fats, and in the liver. Feeding rabbits with a high n-3 PUFA diet led to a decrease in the oxidative stability of perirenal fat and the Longissimus dorsi muscle, and to an inhibition of stearoyl-CoA-desaturase activity in liver and in adipose tissues, but not in muscle.