Effects of Propionibacterium strains on ruminal fermentation, nutrient digestibility and methane emissions in beef cattle fed a corn grain finishing diet

Abstract

Twenty ruminally cannulated beef heifers were fed a high corn grain diet in a randomized block design to determine the effect of three direct fed microbial (DFM) strains of Propionibacterium on ruminal fermentation, nutrient digestibility and methane (CH 4 ) emissions. The heifers were blocked in five groups on the basis of BW and used in five 28-day periods. Dietary treatments included (1) Control and three strains of Propionibacterium (2) P169, (3) P5, and (4) P54. Strains were administered directly into the rumen at 5 × 10 9 CFU with 10 g of a maltodextrin carrier in a gel capsule; Control heifers received carrier only. All heifers were fed the basal diet (10 : 90 forage to concentrate, dry matter basis). Rumen contents were collected on days 15 and 18, ruminal pH was measured continuously between days 15 and 22, enteric CH 4 emissions were measured between days 19 and 22 and diet digestibility was measured from days 25 to 28. Mean ruminal pH was 5.91 and was not affected by treatments. Similarly, duration of time that pH < 5.8 and 5.6 was not affected by treatment. Likewise, total and major volatile fatty acid profiles were similar among all treatments. No effects were observed on dry matter intake and total tract digestibility of nutrients. Total enteric CH 4 production (g/day) was not affected by Propionibacterium strains and averaged 139 g/day. Similarly, mean CH 4 yield (g CH 4 /kg of dry matter intake) was similar for all the treatments. The relative abundance of total Propionibacteria in the rumen increased with administration of DFM and were greater 3 h post-dosing relative to Control, but returned to baseline levels before feeding. Populations of Propionibacterium P169 were higher at 3 and 9 h as compared with the levels at 0 h. In conclusion, moderate persistency of the inoculated strains within the ruminal microbiome and pre-existing high propionate production due to elevated levels of starch fermentation might have reduced the efficacy of Propionibacterium strains to increase molar proportion of propionate and subsequently reduce CH 4 emissions.

Enteric methane emissions in response to ruminal inoculation of Propionibacterium strains in beef cattle fed a mixed diet

“…However, no effects were observed on total CH 4 emissions due to low persistency of the inoculated strains. Contrary to the previous in vivo studies (Vyas et al 2014a(Vyas et al , 2014b, in vitro batch culture studies with Propionibacterium strains showed promising results with significant reduction in CH 4 production using both high-forage and high-grain diets (Alazzeh et al 2013). The discrepancy between studies might be related to different strains of Propionibacteria used in the in vitro batch culture experiment compared with the in vivo study.…”

“…Recently, the role of Propionibacterium species in reducing CH 4 emissions was explored in beef cattle fed a high-forage diet (Vyas et al 2014a) and a high-grain diet (Vyas et al 2014b); however, inoculated strains failed to increase ruminal propionate proportion and mitigate total CH 4 emissions. It is possible that the lack of effect of Propionibacterium species in those studies was due to the strains selected; thus, the present study examined additional Propionibacterium strains.…”

“…It is possible that the lack of effect of Propionibacterium species in those studies was due to the strains selected; thus, the present study examined additional Propionibacterium strains. The Propionibacterium strains used in the present study were previously screened for their CH 4 mitigation potential in vitro using both forage-and grain-based diets (Alazzeh et al 2013), unlike in the studies of Vyas et al (2014aVyas et al ( , 2014b. Animals used in the present study had no previous exposure to Propionibacterium strains thereby ruling out the possibility of any carry-over effects that might have confounded results in the present study.…”

“…The development of Propionibacterium strains as direct-fed microbials could offer an effective means of increasing ruminal propionate production and reducing enteric methane (CH 4 ) emissions from cattle fed forage-based diets (Jeyanathan et al 2014). Previous studies explored the potential to use Propionibacterium strains to mitigate CH 4 emissions in beef cattle fed high-forage (Vyas et al 2014a) and high-grain diets (Vyas et al 2014b). However, no effects were observed on total CH 4 emissions due to low persistency of the inoculated strains.…”

Development of NIRS calibrations to estimate fecal composition and nutrient digestibility in beef cattle.

“…Fecal samples were analyzed for analytical DM Retsch, Haan, Germany) for determination of starch and nitrogen (N). Starch concentration in the compiled studies was determined using two methods either by enzymatic hydrolysis of α-linked glucose polymers as described by Rode et al (1999) with modifications according to Vyas et al (2014), or a glucoamylase enzymatic reaction followed by oxidation in a YSI 2700 Biochemistry Analyzer (Yellow Springs, OH) with hydrogen peroxide detected on a platinum electrode surface (www.ysilifescience.com). Nitrogen was estimated by flash combustion, followed by gas chromatography and thermal conductivity detection (Carlo Erba Instruments, Milan, Italy) or a LECO N analyzer (Joseph, MI) as described by Watson et al (2003).…”