Impact of oil type and savory plant on nutrient digestibility and rumen fermentation, milk yield, and milk fatty acid profile in dairy cows.

Fat supplements are well known for their multiple beneficial effects on ruminant health, reproduction and productivity, and as a source for certain bioactive compounds in ruminant products. On the other hand, numerous phytochemicals have demonstrated the potential to improve rumen fermentation through modifying the volatile fatty acid (VFA) pattern to favour those with greater energy efficiency, boosting microbial protein synthesis, and decreasing methane emission and ruminal ammonia concentration. Savory is an aromatic plant rich in various phytochemicals (mainly carvacrol and flavonoids) that can alter ruminal metabolism of dietary fatty acids, potentially increasing the production of some bioactive compounds such as conjugated linoleic acids (CLAs). This study aimed to investigate combined effects of oil type (fish oil (FO) versus soybean oil (SO)) and the inclusion of savory (Satureja khuzistanica) plant (SP) in the diet on total tract digestibility of nutrients, rumen fermentation, milk yield and milk fatty acid profile in dairy cattle. Eight multiparous lactating Holstein cows were used in a replicated 4 × 4 Latin square design experiment with four diets and four 21-d periods. During each experimental period consisted of 14 days of adaptation and a 7-day sampling period, cows were randomly assigned to one of the four dietary treatments: the diet supplemented with 2% (DM basis) fish oil (FOD) or soybean oil (SOD), the FOD or SOD plus 370 g DM/d/head SP (FODs, SODs, respectively). The experimental diets were arranged in a 2 × 2 factorial design, with the fat sources as the first and SP as the second factor. The FO-supplemented diets had lower dry matter intake (DMI) and higher total tract digestibility than SO-supplemented diets (P < 0.05), and including SP in the diet improved total tract digestibility of dry matter (DM), organic matter (OM), ether extract (EE), and non-fibrous carbohydrates (NFC) (P < 0.05) without negatively affecting DMI. Rumen pH was lower with SO than with FO diets (P < 0.01) and increased with SP inclusion in the diet (P < 0.05). Total protozoa count and ruminal ammonia concentration decreased, and the branched-chain VFA (BCVFA) proportion increased with SP inclusion in the diet (P < 0.05). Milk production, as well as the concentration and yield of milk components (except lactose concentration) were higher with SO than with FO diets (P < 0.05), but these variables remained unaffected by SP. The milk concentrations of both non-esterified fatty acids (NEFA) and beta-hydroxybutyrate (BHB) were lower with SO compared to FO diets, and these variables were reduced by SP (P < 0.01). The proportions of both mono- and polyunsaturated FA (MUFA and PUFA, respectively) in milk were higher with FO than with SO diets (P < 0.01), and their proportions increased by SP at the expense of saturated FA (SFA) (P < 0.01). Including SP in the diet increased the proportions of all the milk n-3 FA (C18:3c, C20:5, and C22:6) by 21%, 40%, and 97%, respectively, and those of conjugated linoleic acids (C18:2 (c9,t11-CLA) and C18:2 (t10,c12-CLA)) by 23% and 62%, respectively. There was no interaction between oil type and SP for the assessed variables. Fish oil, despite reducing milk production and milk components, was more effective than soybean oil in enriching milk with healthy FA. These findings also show promise for SP as a feed additive with the potential to improve total tract digestibility, rumen fermentation and milk FA composition.

Golbotteh MM ，Malecky M ，Aliarabi H ，Zamani P ... -  《Scientific Reports》

Rubber seed oil and flaxseed oil supplementation alter digestion, ruminal fermentation and rumen fatty acid profile of dairy cows.

Pi Y ，Ma L ，Pierce KM ，Wang HR ，Xu JC ，Bu DP ... -  《-》

Effect of monensin and vitamin E on milk production and composition of lactating dairy cows.

Feeding unsaturated oils to lactating dairy cows impair ruminal biohydrogenation (BH) of unsaturated fatty acids (USFA) and increase ruminal outflow of BH intermediates such as trans-10, cis-12 CLA that are considered to be potent inhibitors of milk fat synthesis. Supplementing lactating dairy cow's rations containing plant origin oils with monensin and/or vitamin E may minimise the formation of trans-10 isomers in the rumen, thereby preventing milk fat depression. Therefore, this study was conducted to evaluate the effects of monensin and vitamin E supplementation in the diets of lactating dairy cows containing whole cottonseed, as the main source of FA on feed intake, milk production and composition, milk fatty acid profile, efficiency of nitrogen (N) utilisation, efficiency of net energy (NE) utilisation and nutrients digestibilities. Four multiparous Holstein lactating dairy cows (86±41 days in milk) were assigned to a balanced 4 × 4 Latin square design. Each experimental period lasted 21 days with a 14 days of treatment adaptation and a 7 days of data collection. The control diet was a total mixed ration (TMR) consisted of 430 g/kg forage and 570 g/kg of a concentrate mixture on dry matter (DM) basis. Cows were randomly assigned to one of the four dietary treatments including control diet (C), control diet supplemented with 150 mg of vitamin E/kg of DM (E), control diet supplemented with 24 mg of monensin/kg of DM (M) and control diet supplemented with 150 mg of vitamin E and 24 mg of monensin/kg of DM (EM). Dry matter intake (DMI) ranged from 19.1 to 19.5 kg/d and was similar among the dietary treatments. Dietary supplementation with vitamin E or monensin had no effect on milk production, milk fat, protein and lactose concentrations, efficiency of utilisation of nitrogen and net energy for lactation (NEL ). Digestibility of DM, organic matter (OM), crude protein (CP) and ether extract (EE) was not affected by the dietary treatments. Digestibility of neutral detergent fibre (NDF) was higher in cows fed with the M and EM diets in relation to those fed the C and E diets. The concentrations of C4:0, C6:0, C8:0, C10:0, C12:0, C14:0, C15:0, trans-10-16:1, cis-9-16:1, 17:0, 18:0, trans-11-18:1, cis-9-18:1, cis-9, trans-11 conjugated linoleic acid (CLA), trans-10, cis-12 CLA, and 18:3n-3 FA in milk fat were not affected by the dietary supplementations. While feeding the M diet tended to decrease milk fat concentration of C16:0, the milk fat concentration of C18:2n-6 FA tended to be increased. Dietary supplementation with vitamin E or monensin had no effect on milk fat concentrations of saturated, unsaturated, monounsaturated, polyunsaturated, short chain and long chain FA, but feeding the M diet numerically decreased milk fat concentration of medium chain fatty acids (MCFA). The results showed that vitamin E and/or monensin supplementations did not improve milk fat content and did not minimise the formation of trans-10 FA isomers in the rumen when whole cottonseed was included in the diet as the main source of fatty acids.

Khodamoradi Sh ，Fatahnia F ，Taherpour K ，Pirani V ，Rashidi L ，Azarfar A ... -  《-》

Plant oil supplements reduce methane emissions and improve milk fatty acid composition in dairy cows fed grass silage-based diets without affecting milk yield.

Four lipid supplements varying in chain length or degree of unsaturation were examined for their effects on milk yield and composition, ruminal CH4 emissions, rumen fermentation, nutrient utilization, and microbial ecology in lactating dairy cows. Five Nordic Red cows fitted with rumen cannulas were used in a 5 × 5 Latin square with five 28-d periods. Treatments comprised total mixed rations based on grass silage with a forage-to-concentrate ratio of 60:40 supplemented with no lipid (CO) or 50 g/kg of diet dry matter (DM) of myristic acid (MA), rapeseed oil (RO), safflower oil (SO), or linseed oil (LO). Feeding MA resulted in the lowest DM intake, and feeding RO reduced DM intake compared with CO. Feeding MA reduced the yields of milk, milk constituents, and energy-corrected milk. Plant oils did not influence yields of milk and milk constituents, but reduced milk protein content compared with CO. Treatments had no effect on rumen fermentation characteristics, other than an increase in ammonia-N concentration due to feeding MA, RO, and SO compared with CO. Lipid supplements reduced daily ruminal CH4 emission; however, the response was to some extent a result of lower feed intake. Lipids modified microbial community structure without affecting total counts of bacteria, archaea, and ciliate protozoa. Dietary treatments had no effect on the apparent total tract digestibility of organic matter, fiber, and gross energy. Treatments did not affect either energy secreted in milk as a proportion of energy intake or efficiency of dietary N utilization. All lipids lowered de novo fatty acid synthesis in the mammary gland. Plant oils increased proportions of milk fat 18:0, cis 18:1, trans and monounsaturated fatty acids, and decreased saturated fatty acids compared with CO and MA. Both SO and LO increased the proportion of total polyunsaturated fatty acids, total conjugated linolenic acid, and cis-9,trans-11 conjugated linoleic acid. Feeding MA clearly increased the Δ9 desaturation of fatty acids. Our results provide compelling evidence that plant oils supplemented to a grass silage-based diet reduce ruminal CH4 emission and milk saturated fatty acids, and increase the proportion of unsaturated fatty acids and total conjugated linoleic acid while not interfering with digestibility, rumen fermentation, rumen microbial quantities, or milk production.

Bayat AR ，Tapio I ，Vilkki J ，Shingfield KJ ，Leskinen H ... -  《-》

Effect of camelina oil or live yeasts (Saccharomyces cerevisiae) on ruminal methane production, rumen fermentation, and milk fatty acid composition in lactating cows fed grass silage diets.

The potential of dietary supplements of 2 live yeast strains (Saccharomyces cerevisiae) or camelina oil to lower ruminal methane (CH4) and carbon dioxide (CO2) production and the associated effects on animal performance, rumen fermentation, rumen microbial populations, nutrient metabolism, and milk fatty acid (FA) composition of cows fed grass silage-based diets were examined. Four Finnish Ayrshire cows (53±7 d in milk) fitted with rumen cannula were used in a 4×4 Latin square with four 42-d periods. Cows received a basal total mixed ration (control treatment) with a 50:50 forage-to-concentrate ratio [on a dry matter (DM) basis] containing grass silage, the same basal total mixed ration supplemented with 1 of 2 live yeasts, A or B, administered directly in the rumen at 10(10) cfu/d (treatments A and B), or supplements of 60g of camelina oil/kg of diet DM that replaced concentrate ingredients in the basal total mixed ration (treatment CO). Relative to the control, treatments A and B had no effects on DM intake, rumen fermentation, ruminal gas production, or apparent total-tract nutrient digestibility. In contrast, treatment CO lowered DM intake and ruminal CH4 and CO2 production, responses associated with numerical nonsignificant decreases in total-tract organic matter digestibility, but no alterations in rumen fermentation characteristics or changes in the total numbers of rumen bacteria, methanogens, protozoa, and fungi. Compared with the control, treatment CO decreased the yields of milk, milk fat, lactose, and protein. Relative to treatment B, treatment CO improved nitrogen utilization due to a lower crude protein intake. Treatment A had no influence on milk FA composition, whereas treatment B increased cis-9 10:1 and decreased 11-cyclohexyl 11:0 and 24:0 concentrations. Treatment CO decreased milk fat 8:0 to 16:0 and total saturated FA, and increased 18:0, 18:1, 18:2, conjugated linoleic acid, 18:3n-3, and trans FA concentrations. Decreases in ruminal CH4 production to treatment CO were related, at least in part to lowered DM intake, whereas treatments had no effect on ruminal CH4 emission intensity (g/kg of digestible organic matter intake or milk yield). Results indicated that live yeasts A and B had no influence on animal performance, ruminal gas production, rumen fermentation, or nutrient utilization in cows fed grass silage-based diets. Dietary supplements of camelina oil decreased ruminal CH4 and CO2 production, but also lowered the yields of milk and milk constituents due to an adverse effect on intake.

Bayat AR ，Kairenius P ，Stefański T ，Leskinen H ，Comtet-Marre S ，Forano E ，Chaucheyras-Durand F ，Shingfield KJ ... -  《-》