The Effect of Different Concentrations of Total Polyphenols from Paulownia Hybrid Leaves on Ruminal Fermentation, Methane Production and Microorganisms

This experiment was conducted to study the effects of different concentrations of polyphenols of Paulownia Clon In Vitro 112® leaves or their particular parts on in vitro ruminal fermentation, methane production and microbial population. Paulownia leaves with high (PLH; 31.35 mg/g dry matter (DM)), medium (PLM; 26.94 mg/g DM), and low level of polyphenols (PLL; 11.90 mg/g DM) were used from three plantation areas. Lamina (PLLA; 33.63 mg/g DM) and twigs (PLT; 2.53 mg/g DM) of leaves were also collected from the PLM plantation. The chemical analyses of Paulownia leaves indicated that the content of the most basic nutrients (e.g., crude protein concentration of 185 g/kg of DM) were similar to dehydrated alfalfa. The in vitro results showed that the use of Paulownia leaves with the highest content of total polyphenols (PLH and PLLA) decreased methane production, methanogens numbers, and acetate to propionate ratio. In PLT, lowered methane production was followed by reduced substrate degradability and volatile fatty acid (VFA) concentration along with higher acetate to propionate ratio. Therefore, reduction of methane production in PLH and PLLA was attributed to the lowered methanogen population, whereas in PLT it was caused by decreased substrate degradability with the resultant of limited hydrogen availability to the methanogens.

Addition of Active Dry Yeast Could Enhance Feed Intake and Rumen Bacterial Population While Reducing Protozoa and Methanogen Population in Beef Cattle

Urea–lime-treated rice straw fed to Thai native beef cattle was supplemented with dry yeast (DY) (Saccharomyces cerevisiae) to assess total feed intake, nutrient digestibility, rumen microorganisms, and methane (CH4) production. Sixteen Thai native beef cattle at 115 ± 10 kg live weight were divided into four groups that received DY supplementation at 0, 1, 2, and 3 g/hd/d using a randomized completely block design. All animals were fed concentrate mixture at 0.5% of body weight, with urea–lime-treated rice straw fed ad libitum. Supplementation with DY enhanced total feed intake and digestibility of neutral detergent fiber and acid detergent fiber (p < 0.05), but dry matter, organic matter and crude protein were similar among treatments (p > 0.05). Total volatile fatty acid (VFA) and propionic acid (C3) increased (p < 0.05) with 3 g/hd/d DY supplementation, while acetic acid (C2) and butyric acid (C4) decreased. Protozoal population and CH4 production in the rumen decreased as DY increased (p < 0.05). Populations of F. succinogenes and R. flavefaciens increased (p < 0.05), whereas methanogen population decreased with DY addition at 3 g/hd/d, while R. albus was stable (p > 0.05) throughout the treatments. Thus, addition of DY to cattle feed increased feed intake, rumen fermentation, and cellulolytic bacterial populations.

The inhibitory action mode of nitrocompounds on in vitro rumen methanogenesis: a comparison of nitroethane, 2-nitroethanol and 2-nitro-1-propanol

Nitroethane (NE), 2-nitroethanol (NEOH) and 2-nitro-1-propanol (NPOH) were investigated in order to determine their inhibitory effects on in vitro ruminal fermentation and methane (CH4) production of a hay-rich substrate (alfalfa hay: maize meal = 4:1, w/w). The rumen liquor collected from cannulated Holstein dairy cows was incubated at 39 °C for 72 h. The addition of NE, NEOH and NPOH slowed down the fermentation process and notably decreased molar CH4 proportion by 96.8, 96.4 and 35.0%, respectively. The abundance of total methanogen and methanogens from the order Methanobacteriales were all decreased with NE, NEOH and NPOH supplementation. Meanwhile, the nitrocompound addition reduced mcrA gene expression, coenzyme F420 and F430 contents. The correlation analysis showed that CH4 production was correlated positively with the population abundance of total methanogens, Methanobacteriales, mcrA gene expression, coenzyme contents of F420 and F430. The nitrocompound addition decreased acetate concentration and increased propionate and butyrate concentrations in the culture fluid. In summary, both NE and NEOH addition presented nearly the same inhibitory effectiveness on in vitro CH4 production; they were more effective than NPOH. The results of the current study provide evidence that NE, NEOH and NPOH can dramatically decrease methanogen population, mcrA gene expression and the coenzyme content of F420 and F430 in ruminal methanogenesis.

Effect of napier grass supplemented with Gliricidia sepium, Sapindus rarak or Hibiscus rosa-sinensis on in vitro rumen fermentation profiles and methanogenesis

This study examined the supplementation effects of gliricidia leaves(GL, Gliricidia sepium), lerak fruit(LF, Sapindus rarak), or hibiscusleaves(HL, Hibiscusrosa-sinensis) on in vitro rumen fermentation and methanogenesis and made a comparisonwith the Napier grass (NG, Pennisetum purpureum) grass. In vitro rumen fermentation was designed according to a randomized complete block design with four replications and seven treatments: NG, GL, LF, HL, NG 70% + GL 30%, NG 70% + LF 30%and NG 70% + HL 30%. The generated data were subjected to analysis of variance (ANOVA) with Duncan’s multiple range test and compared among treatment means.Addition of a plant containing saponin such as LF or HL to NG did not alter gas production after 24 and 48 h of incubation period in comparison to NG alone.The HLalone or blended with NGproduced the highest IVOMDduring the fermentation processas compared to other treatments (P<0.05). Adding LF supplement either singly or in combination significantly (P<0.05) reduced methane production in terms of %TVFA as compared to NG. Supplementation of LF plants has shifted VFA proportion towards more propionate and less acetate. The microbial population of LF, whether single or in combination had a tendency to reduce the rumen protozoa population but had no effect on methanogen population. It can be concluded that utilization of saponin-rich materials is particularly beneficial for reducing ruminal methane emission.

Comparative Analysis of the Methanogen Diversity in Horse and Pony by UsingmcrAGene and Archaeal 16S rRNA Gene Clone Libraries

Comparative analysis of methanogen compositions in the feces of horse and pony was carried out by constructing theα-subunit of methyl coenzyme-M reductase (mcrA) gene and 16S ribosomal RNA gene (16S rRNA) clone libraries. ThemcrAclone library analysis indicated that Methanomicrobiales was predominant in both horse and pony. Furthermore, most of the clones of the 16S rRNA gene library showed that Methanomicrobiales was also predominant in horse and pony, but the LIBSHUFF analysis showed that the horse and pony libraries were significantly different (P<0.05). Most of operational taxonomic units (OTUs) showed low similarity to the identified methanogens in both themcrAand the 16S rRNA clone libraries. The results suggest that horse and pony harbor unidentified and novel methanogens in their hindgut. The methanogen population was higher in horse than in pony; however, the anaerobic fungal population was similar in horse and pony. The methanogen diversity was different between two breeds ofEquus caballus.