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

Abstract

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.

Effect of incremental amounts of camelina oil on milk fatty acid composition in lactating cows fed diets based on a mixture of grass and red clover silage and concentrates containing camelina expeller

“…Increases in CO decreased silage and total DMI by 27 and 18%, respectively, in the absence of changes in total-tract NDF digestibility. The magnitude of decreases in intake were higher compared with a recent report of a 12% decrease in DMI in response to inclusion of 60 g of CO/kg of DM that increased the FA content of a TMR based on grass silage from 22 to 77 g/kg of DM (Bayat et al, 2015). However, both the proportion of concentrate in diet DM (from 50 to 55%) and apparent total-tract OM digestibility (from 74 to 75%) were similar in this and the earlier report (50 and from 69 to 72%, respectively; Bayat et al, 2015).…”

“…The magnitude of decreases in intake were higher compared with a recent report of a 12% decrease in DMI in response to inclusion of 60 g of CO/kg of DM that increased the FA content of a TMR based on grass silage from 22 to 77 g/kg of DM (Bayat et al, 2015). However, both the proportion of concentrate in diet DM (from 50 to 55%) and apparent total-tract OM digestibility (from 74 to 75%) were similar in this and the earlier report (50 and from 69 to 72%, respectively; Bayat et al, 2015). The larger decrease in DMI to CO in the present experiment might have been related to the inclusion in concentrates fed separately at specified time points, leading to a more sudden release of unsaturated FA in the rumen compared with adding CO as part of a TMR (Bayat et al, 2015).…”

“…Feeding grass silage and RCS as a mixture often increases DMI and milk yield compared with feeding grass or RCS as sole forages (Vanhatalo et al, 2009;Halmemies-Beauchet-Filleau et al, 2014). Several studies have shown that camelina seeds or CO can be used to alter milk fat composition in cows fed diets based on maize silage (Hurtaud and Peyraud, 2007), RCS (Halmemies-Beauchet-Filleau et al, 2011), or grass silage (Mihhejev et al, 2007;Bayat et al, 2015) and in goats (Pikul et al, 2014) and sheep (Szumacher-Strabel et al, 2011) based on a mixture of alfalfa silage, grass silage, and meadow hay. However, no single experiment has examined the effect of CO inclusion rate in cows fed diets containing a mixture of grass silage and RCS.…”

“…Interest in cultivating camelina (Camelina sativa) as an alternative to linseed has been increasing due to low input requirements, a high drought tolerance, and an ability to adapt to changes in climatic and soil conditions (Zubr, 2003a). Camelina oil (CO) is a rich source of 18-carbon n-6 PUFA in the form of cis-9,cis-12 18:2 [linoleic acid (LA); 15 to 16 g/100 g of FA] and n-3 PUFA (ALA; 37 to 38 g/100 g of FA; Zubr, 2003b;Bayat et al, 2015). Camelina seeds are also relatively abundant in essential AA (Zubr, 2003b), highlighting the potential of camelina as a high-quality feed for ruminants.…”

Review of current in vivo measurement techniques for quantifying enteric methane emission from ruminants

“…The SF 6 technique has been used to estimate CH 4 emission using samples of rumen gas, rather than breath samples (Bayat et al, 2015), however Beauchemin et al (2012) recommended against the use of the SF 6 technique in rumen cannulated animals. Beauchemin et al (2012) concluded that the rumen cannulae would need to be tight fitting to minimize gas leakage, and more animals would be required to overcome additional variability.…”