Effect of Amomum villosum essential oil as an additive on the chemical composition, fermentation quality, and bacterial community of paper mulberry silage.

Paper mulberry (Broussonetia papyrifera L., PM) is being used as a new type of animal protein feed to address the feed crisis. To investigate the effect of additives on the chemical composition, fermentation quality, and bacterial community of PM silage (at room temperature, 25°), paper mulberry was fermented with formic acid (FA), Amomum villosum essential oil (AVEO) and lactic acid bacteria (LAB) inoculant treatments. The results showed that fresh PM had a low water-soluble carbohydrate (WSC) content and large amounts of unclassified bacteria. Compared with the CK and LAB treatments, the FA and AVEO treatments significantly (P < 0.05) decreased the pH and increased the lactic acid content of PM silage after 60 days of ensiling. In the AVEO-treated silages the abundance of Lactococcus in the early stage of ensiling increased by 14.09%, the abundances of Levilactobacillus and Lentilactobacillus in the late stage of ensiling increased by 58.34 and 91.12%, respectively, and the abundance of Stenotrophomonas decreased by 94.71%, resulting in improved PM silage quality. These results confirmed that AVEO could potentially be developed as a new additive for improving the fermentation quality of silage.

Ambient ultraviolet radiation: A new factor affecting anaerobic fermentation of oat and subsequent methane emissions.

To investigate the effect of ambient ultraviolet (UV) radiation on the Qinghai-Tibetan Plateau on anaerobic fermentation and subsequent methane emissions, oats grown under different ambient UV conditions (UV1, 100% ambient UV radiation; UV2, 50% ambient UV radiation) were fermented with molasses and Lactobacillus plantarum (LP) inoculant treatments. The UV2 treatment increased (P < 0.05) epiphytic bacterial counts and reduced (P < 0.05) the water-soluble carbohydrate contents of oat. Both the UV2 treatment and the LP inoculant substantially increased the abundance of Lactobacillus and inhibited detrimental microorganisms (enterobacteria and yeasts) during anaerobic fermentation, resulting in the absence of butyric acid. The UV2 treatment increased (P < 0.05) the acid detergent fiber contents after anaerobic fermentation and indirectly increased (P < 0.05) methane emissions by 8.52-14.69% during in vitro ruminal digestion. This study demonstrated that low ambient UV radiation during cultivation facilitated anaerobic fermentation and consequently enhanced subsequent methane emissions from the rumen.

Effects of inoculants on the fermentation characteristics and in vitro digestibility of reed canary grass (Phalaris arundinacea L.) silage on the Qinghai-Tibetan Plateau.

To effectively use local available grass resources to cover the winter feed shortage on the Qinghai-Tibetan Plateau, direct-cut and wilted reed canary grass (RCG) silages were prepared by using a rolled-bale system, and their ensiling characteristics and in vitro digestibility were studied. Silages were treated without (control) or with inoculants including LP (Lactobacillus plantarum), LPLB (L. plantarum, L. buchneri), and LPLBc (L. plantarum, L. buchneri, and cellulase), and were stored at ambient temperature (5.7-14.6°C) for 90 days. Compared with control, the inoculated silages increased (p < .05) lactic acid and acetic acid contents, and reduced (p < .05) final pH value and ammonia-N ratio of total N. The highest WSC content (41.2 g/kg DM) occurred for LPLB-inoculated silage, whereas LPLBc-treated silage displayed the lowest contents of NDF (522.9 g/kg DM) and ADF (275.5 g/kg DM). In addition, LPLBc-inoculated silage had the highest in vitro gas production (51.0 ml/g DM), in vitro DM digestibility (619.3 g/kg DM), and metabolic energy (9.6 kJ/kg DM). These results confirmed that treatments with inoculants at ensiling could improve silage fermentation and in vitro digestibility of RCG, and this could be a potential winter feed for animals on the Qinghai-Tibetan Plateau.

[Risk assessment and analysis of polycyclic aromatic hydrocarbons in the surface sediments of Xinglin Bay Suburb Rivers of Xiamen].

The concentrations of 16 polycyclic aromatic hydrocarbons (PAHs), declared as carcinogens by USEPA, were measured in the sediment samples (n = 19) collected along Xinglin Bay rivers/canals present in Xiamen. PAHs were extracted using accelerated solvent extraction system and analyzed using gas chromatography-mass spectrometry (GC-MS). The possible sources of PAHs and their health risk were investigated. Among selected PAHs, 13 PAHs were detected in the surface sediments. Total concentrations of PAHs in the surface sediments ranged from 413.00 to 2748.81 ng x g(-1), with a mean value of 949.56 ng x g(-1). The mean concentration of highly carcinogenic compounds such as benzo [k] fluoranthene (BkF) and benzo [g, h, i] perylene (BghiP) were 69.15 ng x g(-1) and 49.86 ng x g(-1), respectively and counted for 73.68% out of the total samples. The dominant PAH compounds were 2, 3 and 4 rings and counted for 61.03% and 23.53% , respectively; while 5-6 rings containing PAHs were accounted for 15.82%. According to the results, 68.42% of samples were moderately contaminated, while 31.58% were highly contaminated with PAHs. Based on the ratios of Ant/(Ant + Phe) and Fla/(Fla + Pyr), it cleared that PAHs in surface sediments were mainly derived from fossil fuel and combustion products. Principal component analysis results and sediment quality benchmarks (mSQG-Q) were used for risk assessment of these PAH contaminated sediments. The risk SQG-Q of 16 PAHs were less than 0.50. Comprehensive content, composition and SQG-Q showed that a certain degree of ecological risks of PAH pollution existed in the surface sediments, particularly in the sites close to Xinglin Industrial Zone (2, 3, 5 and 9) and Gangtou(13), which need further research work and proper attentions.