The community structure and microbial linkage of rumen protozoa and methanogens in response to the addition of tea seed saponins in the diet of beef cattle

Background: This study investigated changes in rumen protozoal and methanogenic communities, along with the correlations among microbial taxa and methane(CH_4) production of six Belmont Red Composite beef steers fed tea seed saponins(TSS). Animals were fed in three consecutive feeding periods, a high-grain basal diet for 14 d(BD period) then a period of progressive addition of TSS to the basal diet up to 30 g/d for 20 d(TSS period), followed by the basal diet for 13 d without TSS(BDP post-control period).Results: The study found that TSS supplementation decreased the amount of the protozoal genus Entodinium and increased Polyplastron and Eudiplodinium genera. During BDP period, the protozoa community of steers did not return to the protozoal profiles observed in BD period, with higher proportions of Metadinium and Eudiplodinium and lower Isotricha. The addition of TSS was found to change the structure of methanogen community at the subgenus level by decreasing the abundance of methanogens in the SGMT clade and increasing the abundance of methanogens in the RO clade. The correlation analysis indicated that the abundance of SGMT clade methanogens were positively correlated with Isotricha, and Isotricha genus and SGMT clade methanogens were positively correlated with CH_4 production. While RO clade were positively correlated with the proportion of Metadinium genus, which was negatively correlated with CH_4 emission.Conclusions: These results suggest that different genera of rumen protozoa ciliates appear to be selectively inhibited by TSS, and the change in methanogen community at the subgenus level may be due to the mutualistic relationships between methanogens and rumen ciliates.

Preparation and Dye Adsorption of Low-cost Polyaniline-tea Saponin Nanocomposites

Four polyaniline-tea saponin (PTS) nanocomposites were prepared by an in-situ polymerization with tea saponin (TS) as a biosurfactant,and they were used to remove organic dyes from aqueous solution.The PTS nanocomposites were characterized by using field emission scanning electron microscopy,the Fourier transform infrared spectroscopy,the Ultraviolet-visible spectroscopy,and the thermogravimetric analysis.The adsorption performances of the PTS nanocomposites for organic dyes were studied by a static adsorption method.The experimental results reveal that adsorption capacities of the PTS nanocomposites are higher than that of pure polyaniline.Especially,the PTS nanocomposites exhibit excellent adsorption performances for anionic dyes because of the electrostatic interaction between the positively charged nitrogen atoms on the PTS chains and the negatively charged sulfonate ions in the anionic dyes.According to the adsorption kinetics and thermodynamics results,the adsorption processes of PTS20 for CR and AB74 follow well with the pseudo second-order and Langmuir isotherm models.It is indicated that TS should be very useful in the preparation of PTS nanocomposite and in removal of toxic dyes from waste water.

Evaluation of Effects of Tea Saponin on Behavior, Growth and Development of Cylas formicarius (Coleoptera: Brentidae)

[Objectives] This study was conducted to expand the insect resistance spectrum of tea saponin, and its control effect on Cylas formicarius and the potential as an insecticide for pest control were explored. [Methods] The olfactory avoidance rate of C. formicarius to tea saponin aqueous solution was determined by Y-type olfactometer;the feeding avoidance rate of C. formicarius to tea saponin was determined by the selective method;the antifeedant rate of C. formicarius to tea saponin was determined by non-selective method;and the development duration and mortality of C. formicarius under the influence of tea saponin were determined by artificial feeding method. [Results] C. formicarius had no significant olfactory tendency to every concentration of tea saponin, and the olfactory avoidance rate of 20.0% tea saponin aqueous solution was only 9.14%. Tea saponin had a feeding avoidance effect on C. formicarius, and the avoidance rate increased with the increase of tea saponin concentration. At 6 h, the feeding avoidance rates of 0.5%, 1.0%, 5.0%, 10.0% and 20.0% tea saponin on C. formicarius were 58.14%, 77.77%, 88.23%, 95.00% and 97.65 %, respectively;and the feeding avoidance effect at 6 h was significant, and the feeding avoidance rate was higher than that of 1 h. Tea saponin had a significant antifeedant effect on C. formicarius, and the longer the feeding time, the higher the antifeedant rate. At 72 h, the antifeedant rates of 0.5%, 1.0%, 5.0%, 10.0 % and 20.0% tea saponin to C. formicarius were 63.01%, 67.54%, 97.14 %, 96.42% and 98.57%, respectively. The larval development duration of C. formicarius was shortened with the increase of tea saponin concentration, and the larval death occurred. The development duration of larvae under the influence of 1.0% tea saponin was the shortest, which was 4.01 d shorter than that of the control, and the mortality was the highest, which was 26.65%. [Conclusions] Tea saponin had neither olfactory avoidance effect nor olfactory attracting effect to C. formicarius, but had obvious feeding avoidance effect and strong antifeedant effect. Tea saponin can shorten the development duration of the larvae of C. formicarius and cause the death of the larvae.