ruminal fermentation
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Inhibition of methanogenesis in ruminal cultures was attempted by hindering thiamine availability through its degradation by 'polyphenols' and competition for active sites on enzymes and transporters using thiamine structural analogs. Effects on fermentation were small and not consistently reversed by adding thiamine. Lack of major effects of the compounds evaluated could be due to intracellular synthesis of thiamine covering most requirements.
Agriculture is at the pivot point between anthroposphere, biosphere, and atmosphere. Innovative solutions are needed to reduce agricultural emissions and improve sustainability. Microalgae animal feed could be such a solution. This study aimed to evaluate the effects of 10 freshwater microalgae: Auxenochlorella protothecoides, Chlamydomonas pulvinate, Chlorella luteoviridis, Chlorella variabilis, Euglena mutabilis, Parachlorella kessleri, Stichococcus bacillaris, Tetradesmus acuminatus, Tetradesmus obliquus, and Tetraselmis gracilis, on ruminal methane (CH4) production, nutrient digestibility, and rumen fermentation using the in vitro Hohenheim gas test. The microalgae were cultured in a carbon dioxide (CO2) incubator at 2% CO2, at the optimal conditions for each strain. The highest producers were P. kessleri and T. obliquus, with a biomass concentration of 0.69 and 0.73 g/L·d, respectively. Their PUFA contents ranged from 33.2% to 69.1% of total fatty acids. Microalgae were tested at a 15% replacement in a control basal diet of 40.0% DM grass silage, 40.0% maize silage, 15% hay, and 5% concentrate. Data were analyzed using a mixed model in R. Ruminal CH4 production was reduced by 15.4%, 17.4%, and 16.4% in diets containing A. protothecoides, C. luteoviridis, and P. kessleri, respectively, compared with the control diet. Similarly, these diets reduced in vitro organic matter digestibility by 3.5%, 5.2%, and 5.4%, respectively. However, only A. protothecoides reduced CH4/CO2 ratio by 3.5% compared with the control diet. Propionate molar proportion was decreased by 2.4, 3.0, 2.5, and 2.5 percentage points for diets containing Ch. pulvinate, E. mutabilis, P. kessleri, and T. obliquus, respectively. Marginal effects of dietary variables were analyzed using the generalized additive model framework, revealing a negative relationship between dietary PUFA, sulfur content, and CH4 production, and a negative relationship between dietary PUFA and CH4/CO2 ratio. Incorporating high-PUFA microalgae in ruminant diets shows potential for reducing enteric CH4 emissions, warranting further investigation.
- MeSH
- bachor * metabolismus MeSH
- dieta veterinární MeSH
- fermentace MeSH
- krmivo pro zvířata MeSH
- methan * metabolismus MeSH
- mikrořasy * metabolismus MeSH
- siláž MeSH
- skot MeSH
- sladká voda MeSH
- trávení MeSH
- zvířata MeSH
- Check Tag
- skot MeSH
- zvířata MeSH
- Publikační typ
- časopisecké články MeSH
Fungi can improve stover digestibility due to their ability to secrete oxidative enzymes that depolymerize lignin, allowing the rumen microorganisms to access the polysaccharides of the plant cell wall. Some ascomycetes have shown good delignification capability; however, they have been scarcely evaluated for their ability to improve corn stover (CS) ruminal digestibility. We evaluated the laccase induction by CS of the CMU-196 strain of the ascomycete fungus Didymosphaeria sp. (syn. = Paraconiothyrium sp.). Also, we analyzed the capacity of such strain to modify the cell wall of CS and to improve its digestion by the ruminal microbiota. The CMU-196 strain showed a maximum extracellular laccase activity of 39.74 ± 0.24 U/L when an aqueous stover extract (SE, 10% v/v) was added to the growth medium. The addition of ground stover (GS, 2% w/v) increased the activity to a maximum of 262.27 ± 0.58 U/L. In solid-state fermentation (SSF) assays of GS, the strain degrades cell walls, destabilizing the vessels and tracheids of plant biomass; the protein content reaches a maximum of 33.2 g/kg dry matter (DM) at 70 days, while the crude fiber content shows the highest level of 314 g/kg DM at 14 days. SSF treatment of the CS increased the in vitro ruminal production of gas in a fraction that was considered nondigestible at 18 h, and gas production increased by 14% with respect to the untreated GS at 14 days. The CMU-196 strain can digest the plant cell wall and improve ruminal CS digestibility at a level equivalent to several basidiomycete species.
- MeSH
- Ascomycota enzymologie růst a vývoj metabolismus MeSH
- bachor mikrobiologie MeSH
- biomasa MeSH
- buněčná stěna metabolismus ultrastruktura MeSH
- fermentace MeSH
- krmivo pro zvířata analýza mikrobiologie MeSH
- kukuřice setá metabolismus ultrastruktura MeSH
- lakasa metabolismus MeSH
- lignin metabolismus MeSH
- zvířata MeSH
- Check Tag
- zvířata MeSH
- Publikační typ
- časopisecké články MeSH
