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The objective of this study was to evaluate the effects of using encapsulated nitrate product (ENP) replacing soybean meal in diets differing in concentrate to forage ratio on ruminal fermentation and methane production in vitro using a semi-automatic gas production technique. Eight treatments were used in a randomized complete design with a 2 × 4 factorial arrangement: two diet (20C:80F and 80C:20F concentrate to forage ratio) and four levels of ENP addition (0%, 1.5%, 3.0%, and 4.5% of DM) replacing soybean meal. There was a diet × ENP interaction (p = 0.02) for methane production. According to ENP addition, diets with 80C:20F showed more intense reduction on methane production that 20C:80F. A negative linear effect was observed for propionate production with ENP addition in diet with 80C:20F and to the relative abundance of methanogens Archaea, in both diet. The replacement of soybean meal by ENP in levels up to 3% of DM inhibited methane production due to a reduction in the methanogens community without affecting the organic matter degradability. However, ENP at 4.5% of DM level affected fiber degradability, abundance of cellulolytic bacteria, and propionic acid production, indicating that this level of inclusion is not recommended for ruminant production., (© 2019 Japanese Society of Animal Science.)

An experiment was conducted under in vitro conditions for determining the effect of a raw saponin extract on the ruminal microbial population and in vitro methane production with star grass (Cynodon nlemfuensis) substrate. Treatments were designed according to the quantity of saponin extract: 1) control, without saponins, 2) 0.6 %, 3) 1.2 % and 4) 1.8 % of the DM of raw saponin extract. The basal diet was star grass (C. nlemfuensis). The saponin extract was obtained from Sapindus saponaria fruit and its saponin content was of 139.5 mg, equivalent of diogenin.mL-1. There was a reduction in protozoa population, regardless the saponin level. Its effect on the main cellulolytic bacteria, determined by PCR-RT, showed that the amount of Fibrobacter succinogenes was not modified while the values of Ruminococcus albus were 25.92; 26.72; 25.2 and 22.35 CT for the levels 0; 0.6; 1.2 and 1.8 %, respectively. The acetic acid concentration was not modified by the saponins; the propionic was reduced with 1.2 % inclusion. The concentration of valeric acid was 0.68; 0.62; 0.52 and 0.49 mmol.L-1 for 0, 0.6; 1.2 and 1.8 % of saponin extract, respectively. Saponins increased methanogenic representation and methane production. It is concluded that the saponin extract modulates the fermentative process on reducing protozoa, does not modify the presence of F. succinogenes and decreases that of R. albus, probably due to the fact that both utilize the same resource, space and carbon source in the rumen. The quantity of methanogens was higher with 1.2 and 1.8 % coinciding with the highest methane production. [ABSTRACT FROM AUTHOR]