Rumen metagenome reveals the mechanism of mitigation methane emissions by unsaturated fatty acid while maintaining the performance of dairy cows

Dietary fat content can reduce the methane production of dairy cows;however,the relevance fatty acid(FA)composition has towards this inhibitory effect is debatable.Furthermore,in-depth studies elucidating the effects of unsaturated fatty acids(UFA)on rumen function and the mechanism of reducing methane(CH4)production are lacking.This study exposed 10 Holstein cows with the same parity,similar milk yield to two total mixed rations:low unsaturated FA(LUFA)and high unsaturated FA(HUFA)with similar fat content.The LUFA group mainly added fat powder(C16:0>90%),and the HUFA group mainly replaced fat powder with extruded flaxseed.The experiment lasted 26 d,the last 5 d of which,gas exchange in respiratory chambers was conducted to measure gas emissions.We found that an increase in the UFA in diet did not affect milk production(P>0.05)and could align the profile of milk FAs more closely with modern human nutritional requirements.Furthermore,we found that increasing the UFA content in the diet lead to a decrease in the abundance of Methanobrevibacter in the rumen(|linear discriminant analysis[LDA]score|>2 and P 2 and P<0.05),which ultimately decreased CH4 production(P<0.05).Our results illustrated the mechanism involving decreased CH4 production when fed a UFA diet in dairy cows.We believe that our study provides new evidence to explore CH4 emission reduction measures for dairy cows.

Instructive cartilage regeneration modalities with advanced therapeutic implantations under abnormal conditions

The development of interdisciplinary biomedical engineering brings significant breakthroughs to the field of cartilage regeneration.However,cartilage defects are considerably more complicated in clinical conditions,especially when injuries occur at specific sites(e.g.,osteochondral tissue,growth plate,and weight-bearing area)or under inflammatory microenvironments(e.g.,osteoarthritis and rheumatoid arthritis).Therapeutic implantations,including advanced scaffolds,developed growth factors,and various cells alone or in combination currently used to treat cartilage lesions,address cartilage regeneration under abnormal conditions.This review summarizes the strategies for cartilage regeneration at particular sites and pathological microenvironment regulation and discusses the challenges and opportunities for clinical transformation.