Spent Craft Brewer's Yeast Reduces Production of Methane and Ammonia by Bovine Rumen Microbes

Methane and ammonia are byproducts of rumen fermentation that do not promote animal growth, and methane is a key contributor to anthropogenic climate disruption. Cows eructate every few breaths and typically emit 250–500 L of methane gas daily. Significant research is focused on finding diets and additives that lower the production of methane and ammonia. Emerging research has shown that humulones and lupulones, molecules that are found in the cones of hops (Humulus lupulus), have potential in this regard. These molecules, which are also key flavor components in beer, are biologically active: they are known inhibitors of Gram-positive bacteria. Ruminants' sophisticated digestive systems host billions of microorganisms, and these systems' outputs will likely be affected in the presence of brewer's yeast (Saccharomyces cerevisiae). So-called spent yeast is produced during the beer-brewing process and contains humulones and lupulones in concentrations that vary by beer style, but it is generally discarded as waste. Our research suggests that adding spent craft brewer's yeast to rumen microbes by single time-point 24-h in vitro incubations suppresses production of methane and ammonia. This project examines the correlation between the quantities of hop acids in spent yeast and the production of methane and ammonia by bovine rumen microbes in vitro. We determined, by HPLC, the hop acid concentrations in spent yeast obtained from six beer styles produced at a local brewery. We performed anaerobic incubation studies on bovine rumen microbes, comparing the effects of these materials to a baker's yeast control and to the industry-standard antibiotic monensin. Results include promising decreases in both methane (measured by GC–FID) and ammonia (measured by colorimetric assay) in the presence of craft brewer's yeast, and a strong correlation between the quantities of hop acids in the spent yeast and the reduction of methane and ammonia. Notably, two of the yeast samples inhibited methane production to a greater degree than the industry-standard antibiotic monensin. Our results suggest that spent brewer's yeast has potential to improve ruminant growth while reducing anthropogenic methane emission.

Theoretical Methane Emission Estimation from Volatile Fatty Acids in Bovine Rumen Fluid

Methane production from livestock farming is recognized as an important contributor to global GHGs. Volatile fatty acids (VFAs) found in bovine rumen may be utilized as a substrate for methanogens to form CH4, and thus improvement of quantitative VFA measurements can help facilitate greater understanding and mitigation of CH4 production. This study aims to contribute to the development of more accurate methods for the quantification and specification of VFAs in bovine rumen. The VFAs were analyzed using the conventional method and an alternative catalytic esterification reaction (CER) method. Substantial differences in the detected concentrations of the C3+ VFAs (chain length ≥ 3) were observed between both methods, especially for butyric acid. Evaluation of the sensitivity of both methods to detecting the VFA concentrations in standard solutions confirmed that the values resulting from the CER method were closer to the known concentrations of the standard solution than those from the conventional method. The results of this study provide the first quantitative proof to show the improved accuracy of the measurements of C3+ VFAs when using the CER method compared with the conventional method. Therefore, the CER method can be recommended to analyze the VFAs found in rumen, especially butyric acid and other C3+ VFAs.

Complete Genome Sequences of Three Clostridiales R-7 Group Strains Isolated from the Bovine Rumen in New Zealand

Members of the Clostridiales R-7 group are abundant bacterial residents of the rumen microbiome; however, they are poorly characterized. We report the complete genome sequences of three members of the R-7 group, FE2010, FE2011, and XBB3002, isolated from the ruminal contents of pasture-grazed dairy cows in New Zealand.

Growth and Testicular Spermatozoa Reserve Potential Of Pre-pubertal Rabbits Fed With Diet Containing 16% Bovine Rumen Digesta-BIood Meal Mixture (50:50) In combination With 18% Cooked Macuna Bean Meal

The growth response of pre-pubertal rabbits and their gonadal sperm reserve potential at pubertal stage when fed diets containing a combination of 16% (50-50) bovine rumen digesta-blood meal (BRDBM) mixture and 18% cooked mucuna bean (CMBM). This was in replacement of 500/0 of the maize and 50% of the groundnut cake of a pre-pubertal control diet. Twenty-four male rabbits of mixed breed aged between 6-8 weeks and body weight range 900-915g were randomly allocated to two diets: the control (diet 1) and the experimental (diet 2). Daily feed intake (72.4±7.5g vs 64.0±9.1g), total weight gain (518±1g Vs 406±18g) and Terminal live weight (1427±48g vs 1317±410 were significantly (P <0.05) higher in the control than experimental group. Feed to gain ratio in group I was marginally lower (7.5±2.6g Vs 8.5±1.2g) than for diet 2. However, dressing percentage (68.6±7.00/6 Vs 75.4±9.0%) was significantly higher in the rabbits on diet 2 than diet l. The cost per kg of diet Vs as well as the cost per kg live weight gain (N352.6±O.l VsN344.5H).l) was significantly lower for diet 2 than diet l. The paired testes weight (1.8±0.6g Vs 1.9±0.40, daily sperm production (3.6x 108 Vs 3,8x 108) and testicular spermatozoa reserve were marginally higher in rabbit on diet 2 (experimental) than diet 1 (control). The paired epididymal weight for rabbits on diet 2 was significantly (P <0.05) higher (0.6±0.3g Vs 1.2±0.30 than those on diet l, indicating more efficient sperm storage. The hematological measured were not affected (P>O. 05) by the dietary treatments. The non-significant difference (P>O. 05) in the efficiency of sperm production and sperm reserve between the two diets confirmed that the inclusion of these materials, in the diet of rabbits supports the ventures Of increasing animal protein sources through cheaper rabbits production process in Nigeria

Identification of a Candidate Starch Utilizing Strain of Prevotella albensis from Bovine Rumen

The inclusion of starch-rich feedstuffs, a common practice in intensive ruminant livestock production systems, can result in ruminal acidosis, a condition that can severely impact animal performance and health. One of the main causes of acidosis is the rapid accumulation of ruminal short chain fatty acids (SCFAs) resulting from the microbial digestion of starch. A greater understanding of ruminal bacterial amylolytic activities is therefore critical to improving mitigation of acidosis. To this end, our manuscript reports the identification of a candidate starch utilizer (OTU SD_Bt-00010) using batch culturing of bovine rumen fluid supplemented with starch. Based on 16S rRNA gene sequencing and metagenomics analysis, SD_Bt-00010 is predicted to be a currently uncharacterized strain of Prevotella albensis. Annotation of de novo assembled contigs from metagenomic data not only identified sequences encoding for α-amylase enzymes, but also revealed the potential to metabolize xylan as an alternative substrate. Metagenomics also predicted that SCFA end products for SD_Bt-00010 would be acetate and formate, and further suggested that this candidate strain may be a lactate utilizer. Together, these results indicate that SD_Bt-00010 is an amylolytic symbiont with beneficial attributes for its ruminant host.