Effect of Fish Oil and Linseed Oil on Intake, Milk Yield and Milk Fatty Acid Profile in Goats.

This study aimed to evaluate the effect of incorporating linseed oil and fish oil in the diet on intake, ruminal fermentation, milk yield, and milk fatty acid profiles in dairy goats. Four crossbred Saanen lactating goats in mid-lactation and milking 1.30 ± 0.28 g/day were used in a 4 × 4 Latin square design. The basal diet contained concentrate and Para grass (C:F 40:60). Treatments included a basal diet without oil supplementation (Ctrl) or with 2.5% linseed oil (LO2.5), 2.5% linseed oil and fish oil (3:2, w/w, LFO2.5), and 4.16% linseed oil and fish oil (3:2, w/w, LFO4.16). Diets had no effect on intake, milk yield, milk composition, or ruminal fermentation (p > 0.05). Compared with Ctrl, lower (p < 0.05) proportions of C10:0-C14:0 in milk fat were observed with LFO4.16. Compared with the Ctrl and linseed oil added alone, feeding LFO4.16 led to a greater (p < 0.01) concentration of C18:1 t11. Compared with both the Ctrl and LO2.5 diets, milk c9,t11 CLA was 4.53 and 2.94 times greater with the LFO4.16 diet. Compared with Ctrl and LO2.5 diets (0.06% and 0.08%), goats fed LFO2.5, and LFO4.16 had greater (p < 0.001) concentrations of C22:6n-3 (0.63% and 0.87%). Overall, the combined data suggested that including 4.16% linseed oil and fish oil in the diet of dairy goats was effective in improving the concentrations of health-promoting fatty acids in milk without affecting milk production.

Alterations in skeletal muscle abundance of protein turnover, stress, and antioxidant proteins during the periparturient period in dairy cows fed ethyl-cellulose rumen-protected methionine.

Skeletal muscle turnover helps support the physiological needs of dairy cows during the transition into lactation. We evaluated effects of feeding ethyl-cellulose rumen-protected methionine (RPM) during the periparturient period on abundance of proteins associated with transport AA and glucose, protein turnover, metabolism, and antioxidant pathways in skeletal muscle. Sixty multiparous Holstein cows were used in a block design and assigned to a control or RPM diet from -28 to 60 d in milk. The RPM was fed at a rate of 0.09% or 0.10% of dry matter intake (DMI) during the prepartal and postpartal periods to achieve a target Lys:Met ratio in the metabolizable protein of ∼2.8:1. Muscle biopsies from the hind leg of 10 clinically healthy cows per diet collected at -21, 1, and 21 d relative to calving were used for western blotting of 38 target proteins. Statistical analysis was performed using the PROC MIXED statement of SAS version 9.4 (SAS Institute Inc.) with cow as random effect, whereas diet, time, and diet × time were the fixed effects. Diet × time tended to affect prepartum DMI, with RPM cows consuming 15.2 kg/d and controls 14.6 kg/d. However, diet had no effect on postpartum DMI (17.2 and 17.1 ± 0.4 kg/d for control and RPM, respectively). Milk yield during the first 30 d in milk was also not affected by diet (38.1 and 37.5 ± 1.9 kg/d for control and RPM, respectively). Diet or time did not affect the abundance of several AA transporters or the insulin-induced glucose transporter (SLC2A4). Among evaluated proteins, feeding RPM led to lower overall abundance of proteins associated with protein synthesis (phosphorylated EEF2, phosphorylated RPS6KB1), mTOR activation (RRAGA), proteasome degradation (UBA1), cellular stress responses (HSP70, phosphorylated MAPK3, phosphorylated EIF2A, ERK1/2), antioxidant response (GPX3), and de novo synthesis of phospholipids (PEMT). Regardless of diet, there was an increase in the abundance of the active form of the master regulator of protein synthesis phosphorylated MTOR and the growth-factor-induced serine/threonine kinase phosphorylated AKT1 and PIK3C3, whereas the abundance of a negative regulator of translation (phosphorylated EEF2K) decreased over time. Compared with d 1 after calving and regardless of diet, the abundance of proteins associated with endoplasmic reticulum stress (XBP1 spliced), cell growth and survival (phosphorylated MAPK3), inflammation (transcription factor p65), antioxidant responses (KEAP1), and circadian regulation (CLOCK, PER2) of oxidative metabolism was upregulated at d 21 relative to parturition. These responses coupled with the upregulation of transporters for Lys, Arg, and His (SLC7A1) and glutamate/aspartate (SLC1A3) over time were suggestive of dynamic adaptations in cellular functions. Overall, management approaches that could take advantage of this physiological plasticity may help cows make a smoother transition into lactation.

Alterations in Skeletal Muscle mRNA Abundance in Response to Ethyl-Cellulose Rumen-Protected Methionine during the Periparturient Period in Dairy Cows.

This study aimed to evaluate the effect of feeding ethyl cellulose rumen-protected methionine (RPM) on skeletal muscle mRNA abundance during the periparturient period. Sixty multiparous Holstein cows were used in a block design and assigned to either a control or RPM diet. The RPM was supplied from −28 to 60 days in milk (DIM) at a rate of 0.09% (prepartum) or 0.10% (postpartum) of dry matter (DM), ensuring a Lys:Met in the metabolizable protein of ~2.8:1. Muscle biopsies were collected at −21, 1, and 21 DIM. Thirty-five target genes associated with nutrient metabolism and biochemical pathways were measured via RT-qPCR. The mRNA abundance of genes associated with amino acid (AA) transport (SLC7A8, SLC43A2), carnitine transport (SLC22A5), insulin signaling (IRS1), and antioxidant response (NFE2L2) had diet × time effect (p < 0.05) due to greater abundance in RPM versus CON cows, especially at 1 and 21 DIM. Members of the AA transport (SLC7A8, SLC25A29, SCL38A9), fatty acid ß-oxidation (ACADVL), vitamin transport (SLC5A6, SLC19A2), mTOR pathway (AKT1 and mTOR), antioxidant response (KEAP1, CUL3), CDP-Choline pathway and arginine metabolism had overall greater abundance (p < 0.05) in RPM versus CON cows. Overall, data indicate that RPM can alter nutrient metabolism in the skeletal muscle around parturition partly through alterations in mRNA abundance.

Association of residual feed intake with peripartal ruminal microbiome and milk fatty acid composition during early lactation in Holstein dairy cows.

Residual feed intake (RFI) is a moderately heritable trait of feed efficiency in dairy cows. The main objective of the present study was to assess potential differences in the ruminal microbiome, milk fatty acid (FA) composition, and plasma concentrations of glucose, nonesterified fatty acids (NEFA), and ß-hydroxybutyrate between the most (M-EFF) and the least efficient (L-EFF) dairy cows during early lactation. Forty-seven multiparous Holstein dairy cows with daily ad libitum access to a total mixed ration from 30 d before calving to 30 d in milk were used. Cows were retrospectively classified into M-EFF (i.e., low RFI, n = 29) and L-EFF (high RFI, n = 18) based on a linear regression model. Ruminal digesta and milk samples were collected from each cow at 15 and 30 d in milk for microbiome analysis using 16S rRNA gene sequencing. Microbiome sequencing data were analyzed with the QIIME 2 platform (http://qiime.org/), whereas the microbiome statistical analyses and visual explorations were performed using the web-based MicrobiomeAnalyst platform. Milk FA composition was measured via gas chromatography-mass spectrometry. The statistical model used in SAS 9.4 (SAS Institute Inc.) included RFI, time, and their interactions as fixed effects. The cor() function in R programming was used to determine Pearson correlations between relative abundance of significant bacteria and milk FA. Overall, daily milk yield did not differ due to RFI and averaged 42 ± 1.6 kg for L-EFF and 43 ± 1.3 kg for M-EFF cows. However, M-EFF cows had lower overall dry matter intake (14.9 ± 0.5 kg/d) compared with L-EFF cows (19.2 ± 0.6 kg/d). No incidence of clinical disease was recorded for cows in the study. Compared with L-EFF, overall glucose concentration was lower, whereas NEFA and ß-hydroxybutyrate concentrations were greater in M-EFF cows. Ruminal digesta from both RFI groups had similar bacterial composition, but differed in the relative abundance of some bacteria. Compared with L-EFF, M-EFF cows had greater relative abundance of Lachnospiraceae, Lachnoclostridium, Papillibacter, Desulfovibrio, Sphaerochaeta, Acetobacter, and Histophilus. In contrast, relative abundance of Bifidobacterium, Ruminiclostridium, Prevotellaceae, and Erysipelotrichaceae bacterium was lower in M-EFF cows. Compared with L-EFF, M-EFF cows had greater proportions of long-chain monounsaturated FA, including 16:1 trans-9, 16:1 cis-9, 17:1 trans-10, 17:1 cis-10, 18:1 cis-9, 18:1 cis-11, whereas proportions of medium-chain saturated and 16:0 were lower in M-EFF. Acetate-producing bacteria (Sphaerochaeta and Acetobacter) were positively and significantly correlated (r ≥ 0.24) with concentrations of 16:1 cis-9 and 17:1 cis-10, whereas Prevotellaceae was significantly and negatively correlated (r = -0.25) with these FA. Butyrate-producing bacterium (Papillibacter) had a significant negative correlation (r = -0.27) with concentration of 15:0. Overall, data suggested that feed-efficient cows have unique profiles of ruminal microbiota, some of which are correlated with concentrations of milk FA during early lactation.

Grape seed tannin extract and polyunsaturated fatty acids affect in vitro ruminal fermentation and methane production.

Condensed tannins (CT), one of the most ubiquitous compounds in the plant kingdom, can modulate ruminal nutrient metabolism. Objectives were to study potential interactions of CT and polyunsaturated fatty acids (PUFA) on ruminal fermentation, biohydrogenation (BH), and methane production. Ruminal fluid obtained from lactating Holstein Friesian cows was used. All experiments were carried out as a completely randomized design with the same mixed diet: control (60:40 forage:concentrate) without supplement (CON), 2.5% soybean oil (SBO), and SBO + grape seed tannin extract (GSTE) at 0.2%, 0.4%, 0.6%, or 0.8% dietary DM (ST0.2, ST0.4, ST0.6, and ST0.8, respectively). Compared with CON (84.7 mM), total VFA concentration was not affected by SBO, but decreased (P < 0.001) with ST0.8 vs. ST0.6 (75.3 vs. 78.3 mM). Relative to CON, methane production was depressed (P < 0.001) by 17.7% and 28.0% in ST0.4 and ST0.8. The highest (P < 0.001) mean concentrations of c9,t11 CLA and C18:1 t11 were observed with ST0.4 compared with CON, but there was no difference between SBO and CT-containing diets. Disappearance of C18:2 c9,c12 was 49.1% vs. 50.3% in CON vs. SBO, whereas it ranged from 39.9% to 46.3% in CT-containing diets after 2 h incubation (P < 0.001). Concentrations of c9,t11 CLA with supplemental SBO and ST0.8 nearly peaked (P < 0.001) at 2 h incubation, but this fatty acid peaked (P > 0.05) at 6 h incubation and remained higher (P < 0.001; 15.9-17.0 µg/mL) at 24 h incubation with ST0.2, ST0.4, and ST0.6 compared with other diets (13.5-14.5 µg/mL). Compared with CON (50.6 µg/mL), concentration of C18:1 t11 with SBO and CT-containing diets reached a peak (P < 0.001; 241-265 µg/mL) at 12 h incubation. Concentration of C18:0 was 171%-231% higher (P < 0.001) with SBO and CT relative to CON at 24 h incubation. Overall, these results demonstrated that PUFA in SBO are more effective in modulating ruminal BH and CH4 production when combined with CT. However, high doses of added CT can reduce ruminal VFA concentration. Thus, a level of 0.4% GSTE added to diets containing 2.5% PUFA from plant origin might be suitable for optimizing ruminal fermentation and BH of C18:2 c9,c12 to fatty acid intermediates that could have beneficial effects to human health.

Condensed tannins can modulate methane emissions and ruminal biohydrogenation, but effects depend on type and dose. We used an in vitro fermentation system to investigate the effect of increasing doses (0%, 0.2%, 0.4%, 0.6%, and 0.8% dry matter) of grape tannin seed extract (GSTE) in a diet supplemented at 2.5% dry matter with soybean oil on methane production and biohydrogenation. Feeding soybean oil and GSTE at 0.6% and 0.8% reduced content of ruminal volatile fatty acids. Methane production (mL/g dry matter) was lower in the diet containing GSTE at 0.4%. Inclusion of GSTE at 0.2% and 0.4% increased concentration of C18:2 c9,c112, C18:3n3, c9,t11 conjugated linoleic acid and total polyunsaturated fatty acids after 24 h of incubation. The present findings contribute to a better understanding of the effect of condensed tannins from grape seed extract on ruminal fermentation and biohydrogenation.

Partial substitution of fish oil for linseed oil enhances beneficial fatty acids from rumen biohydrogenation but reduces ruminal fermentation and digestibility in growing goats.

This study was performed to investigate effects of partial replacement of fish oil (FO) for linseed oil (LO) on digestibility, ruminal fermentation and biohydrogenation in growing goats. Experiment 1 was carried out in four growing male goats aged 6 months in a 4 × 4 Latin square design. Goats were fed a basal diet supplemented with 25 g/kg dry matter either LO alone or in combination with tuna FO. Treatments were developed by replacing FO for LO at ratios of 0, 5, 10 and 15 g/kg DM corresponding to FO-0, FO-5, FO-10 and FO-15, respectively. Experiment 2 was carried out in an in vitro incubation system including 12 fermenters with the same four treatments. Each fermenter consisted of 40 mL goat ruminal fluid, 160 mL warm buffer, 2 g mixed substrates, and 50 mg FO-0, FO-5, FO-10 or FO-15. Fish oil inclusion reduced (P < 0.05) digestibility and nitrogen retention in Experiment 1. Increasing doses of FO in the diet induced a strong drop (P < 0.001) in ruminal total volatile fatty acid (VFA) concentration and protozoa population at 3 h post incubation, but did not affect individual VFA proportions. Substitution of FO for LO decreased mean concentrations of C18:0 (P = 0.057), c-9,c-12 C18:2 and C18:3n-3 (P < 0.001), but increased (P < 0.001) C20:5n-3 and C22:6n-3. Feeding FO-10 enhanced formation of ruminal c-9,t-11 conjugated linoleic acid (CLA) concentration compared with FO-0. Overall, combined data suggest that to improve ruminal concentrations of C20:5n-3, C22:6n-3, and c-9,t-11 CLA for deposition in tissues or milk with minimal risk of affecting digestibility and ruminal fermentation, a dietary supplementation of 15 g/kg LO and 10 g/kg FO would be suitable.

Effect of linseed oil supplementation on performance and milk fatty acid composition in dairy cows.

Thirty-six Holstein-Friesian crossbred lactating dairy cows were used to determine the effects of linseed oil supplementation on performance and milk fatty acid (FA) profile. Three treatments were as follows: basal diet (56:44 Roughage:concentrate [R:C] ratio, dry matter basis) supplemented with 500 g of palm oil as control (PO), 500 g mixture (1:1, w/w) of palm oil and linseed oil (POLSO) and 500 g of linseed oil (LSO). The LSO supplementation had no effects on total dry matter intake (DMI), milk yield and milk composition. Compared to control cows, cows supplemented with LSO increased milk concentrations of cis-9,trans-11 conjugated linoleic acid (CLA) and n-3 FA (P < 0.05), particularly C18:3n-3, C20:5n-3 and C22:6n-3. Feeding LSO reduced concentrations of milk short- and medium-chain saturated fatty acids (P < 0.05) while it increased concentration of milk unsaturated fatty acids (P < 0.05). Milk proportions of n-3 FA increased, whereas n-6/n-3 ratio decreased in the LSO as compared with the control (P < 0.05). In conclusion, supplementing dairy cows' diet based on corn silage with LSO at 500 g/day could improve the nutritional value of milk with potential health-beneficial FA without detrimental effect on milk composition or cow's performance.

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.

Milk Production and Income over Feed Costs in Dairy Cows Fed Medium-roasted Soybean Meal and Corn Dried Distiller's Grains with Solubles.

The aims of this study were to determine the effects of feeding medium-roasted soybean meal (SBM) and corn dried distiller's grains with solubles (CDDGS) in dairy cows on milk production and income over feed costs. A randomized complete block design experiment was conducted with 24 crossbred multiparous Holstein Friesian dairy cows in early- and mid-lactation. Four dietary treatments were as follows: basal diet without feed substitute (Control), 7.17% dry matter (DM) roasted SBM replaced for concentrate (R-SBM), 11.50% DM CDDGS replaced for concentrate (DDGS), and 3.58% DM roasted SBM plus 5.75% DM CDDGS replaced for concentrate (SB-DG). The roasted SBM was produced using a medium-heated treatment at 100°C for 180 min. Dry matter intake was not affected by feeding high rumen undegradable protein (RUP) sources, but the replacement of roasted SBM and CDDGS for concentrate significantly improved (p<0.001) RUP intake (0.90, 0.86, and 0.88 kg/d corresponding to R-SBM, DDGS, and SB-DG) compared to the control (0.61 kg/d). Feeding roasted SBM and CDDGS alone or in combination had no significant effect on milk composition of dairy cows (p>0.05), whereas milk yield was significantly increased by 3.08 kg/d in the SB-DG group relative to the control group (p<0.01). Net income was meaningfully increased (p<0.05) from 4th week post feeding, the SB-DG group reached the greatest net income ($3.48/head/d) while the control group had the lowest value ($2.60/head/d). In conclusion, the use of CDDGS alone or in combination with medium-roasted SBM as substitute for concentrate in lactating dairy cattle diet led to improved milk production and net income over feed costs without affecting total dry matter intake and milk composition, while feeding medium-roasted SBM seemed to show intermediate values in almost parameters.

Effects of linseed oil or whole linseed supplementation on performance and milk Fatty Acid composition of lactating dairy cows.

The objective of this study was to determine the effects of linseed oil or whole linseed supplementation on performance and milk fatty acid composition of lactating dairy cows. Thirty six Holstein Friesian crossbred lactating dairy cows were blocked by milking days first and then stratified random balanced for milk yields and body weight into three groups of 12 cows each. The treatments consisted of basal ration (53:47; forage:concentrate ratio, on a dry matter [DM] basis, respectively) supplemented with 300 g/d of palm oil as a positive control diet (PO), or supplemented with 300 g/d of linseed oil (LSO), or supplemented with 688 g/d of top-dressed whole linseed (WLS). All cows were received ad libitum grass silage and individually fed according to the treatments. The experiment lasted for 10 weeks including the first 2 weeks as the adjustment period, followed by 8 weeks of measurement period. The results showed that LSO and WLS supplementation had no effects on total dry matter intake, milk yield, milk composition, and live weight change; however, the animals fed WLS had higher crude protein (CP) intake than those fed PO and LSO (p<0.05). To compare with the control diet, dairy cow's diets supplemented with LSO and WLS significantly increased milk concentrations of cis-9, trans-11-conjugated linoleic acid (CLA) (p<0.05) and n-3 fatty acids (FA) (p<0.01), particularly, cis-9,12,15-C18:3, C20:5n-3 and C22:6n-3. Supplementing LSO and WLS induced a reduction of medium chain FA, especially, C12:0-C16:0 FA (p<0.05) while increasing the concentration of milk unsaturated fatty acids (UFA) (p<0.05). Milk FA proportions of n-3 FA remarkably increased whereas the ratio of n-6 to n-3 decreased in the cows supplemented with WLS as compared with those fed the control diet and LSO (p<0.01). In conclusion, supplementing dairy cows' diet based on grass silage with WLS had no effect on milk yield and milk composition; however, trans-9- C18:1, cis-9, trans-11-CLA, n-3 FA and UFA were increased while saturated FA were decreased by WLS supplementation. Therefore, it is recommended that the addition 300 g/d of oil from whole linseed should be used to lactating dairy cows' diets.