Enriching the nutritive value of marigold (Tagetes erecta L) crop residues as a ruminant feed by lactic acid bacteria during ensilage.

BACKGROUND: Marigold (Tagetes erecta L) accounts for over half of the world's loose flower production, and marigold crop residue (MCR) are abundantly available and should be used as a forage. In this study, MCR from the last commercial flower pickings was ensilaged with lactic acid bacteria (LAB) and the shift in their volatile organic compounds (VOCs) profiles was monitored. Samples were collected at 6 different times during ensilage (3, 6, 9, 12, 15, 30 days) to determine and quantify the VOCs changes using a solid-phase microextraction (SPME) technique and gas chromatography - mass spectrometry (GC-MS). RESULTS: After 30 days, the caryophyllene and piperitone, which account for 14.7 and 12.1% of total VOCs, decreased by 32.9 and 9.6% respectively, alcohols increased from 2.8 to 8.1%, and the acetic acid content increased by 560%. CONCLUSION: We have confirmed LAB can degrade the content of terpenes and enhance the content of alcohols and acids in MCR, which was for the first time on terpene degradation in fodder by ensilage. These results have shed light on our understanding of how to improve fodder odor and to enhance terpene degradation by lactic acid bacteria fermentation.

Antimicrobial property, cytocompatibility and corrosion resistance of Zn-doped ZrO2/TiO2 coatings on Ti6Al4V implants.

Zn-doped ZrO2/TiO2 porous coatings (Zn-ZrO2/TiO2) were prepared on the surface of titanium alloy (Ti6Al4V) by a hybrid approach of magnetron sputtering and micro-arc oxidation (MAO). The microstructures, phase constituents and elemental states of the coating were investigated by scanning electron microscope (SEM) equipped with energy dispersive spectroscopy (EDS), X-ray diffraction (XRD), and X-ray photoelectron spectroscopy (XPS). The results demonstrate that the Zn-ZrO2/TiO2 coatings are porous and its thickness is approximately 13µm. The major phases in the oxidation coating are tetragonal ZrO2 (t-ZrO2), cubic ZrO2 (c-ZrO2) and rutile TiO2. XPS result reveals that Zn exists as ZnO in the Zn-ZrO2/TiO2 coatings. The biological experiments indicate that Zn-ZrO2/TiO2 coatings exhibit not only excellent antibacterial property against Gram-positive Staphylococcus aureus (S. aureus), but also favorable cytocompatibility. In addition, the corrosion resistance of the coating is also appreciably improved in the simulated body fluids (SBF), which can ensure better biocompatibility in body fluids.