ABSTRACT
It was shown that microRNAs (miRNAs) play an important role in the synthesis of milk fat; thus, this manuscript evaluated whether exogenous miRNA (xeno-miRNAs) from alfalfa could influence the milk fat content in dairy cows. At first, mtr-miR168b was screened from dairy cow milk and blood. Then, EdU staining, flow cytometry, Oil Red O staining, qRT-PCR, and WB were applied to explore the effect of xeno-miR168b on the proliferation, apoptosis, and lipid metabolism of bovine mammary epithelial cells (BMECs). Finally, in order to clarify the pathway that regulated the lipid metabolism of BMECs using xeno-miR168b, a double-luciferase reporter assay was used to verify the target gene related to milk fat. These results showed that overexpression of xeno-miR168b inhibited cell proliferation but promoted apoptosis, which also decreased the expression of several lipid metabolism genes, including PPARγ, SCD1, C/EBPß, and SREBP1, significantly inhibited lipid droplet formation, and reduced triglyceride content in BMECs. Furthermore, the targeting relationship between CPT1A and xeno-miR168b was determined and it was confirmed that CPT1A silencing reduced the expression of lipid metabolism genes and inhibited fat accumulation in BMECs. These findings identified xeno-miR168b from alfalfa as a cross-kingdom regulatory element that could influence milk fat content in dairy cows by modulating CPT1A expression.
ABSTRACT
Even though forage and grazing lands represent the largest land use in the United States, the number of forage faculty positions nationwide has decreased by 47% in the last 15 years, with only an estimated 2.3 forage research and Extension full-time equivalents (FTE) per state. This challenge has made partnerships with county/regional agents and Extension faculty from other states an increasingly important component of a successful Extension program. Whereas virtual/online programs existed prior to 2020, people of all ages are currently more comfortable and adept with virtual technology because of the COVID-19 pandemic. Moving forward, virtual meetings and hybrid meetings will likely become more routine, making it possible to disseminate knowledge to producers locally and across the state, region, and country concurrently. This approach will enable Extension educators to be more efficient in their knowledge transfer as illustrated by programs such as the Bermudagrass Hay Summit which has seen an almost six-fold increase in attendance from 2020 to 2021 because travel is not required. Lastly, there is a largely untapped opportunity in on-farm demonstrations and research. An example of how this can positively affect adoption of new technology is the regional program Alfalfa in the South. This program combines both on-farm and experiment station research. As a result of on-farm demonstrations, producer interest in adoption of alfalfa across Alabama and Georgia has increased in the last 3 years. There are many challenges to Extension programming in forages, but there are also ample opportunities to partner with other state Extension programs, as well as with producers to disseminate forage and pasture management effectively and efficiently to the forage and livestock sectors across the United States.
ABSTRACT
Phosphorus (P) is one of the essential nutrients for alfalfa (Medicago sativa L.) growth, but P deficiency in soil is a common phenomenon. Applying an appropriate amount of P fertilizer for alfalfa in the establishment year improves winter survival, helps achieve sustainable high yields, and promotes the best economic returns. The objective of this study was to determine the effect of different P fertilization rates (0, 22, 44, and 66 kg P ha−1) on winter survival, forage yield, and root traits of two late-summer seeded alfalfa cultivars (dormant and semi-dormant) in the establishment and first production year. Our results showed that applying an appropriate amount of P fertilizer can increase forage yield and enhance the persistence of late-summer seeded alfalfa by promoting the development of crown and root traits and improving winter survival, especially for semi-dormant cultivars. Late-summer seeding and application of appropriate P fertilizer rates are effective agronomic methods for alfalfa in cold and arid winter regions, and can be used as strategies to improve fertility and stabilize soil from wind erosion for sustainable agriculture. To obtain high rate of survival in winter, the optimal P fertilization rates for the dormant and semi-dormant alfalfa cultivars in this study were 31.4 and 41.3 kg P ha−1, whereas the optimum P application rates for high forage yields were 31.3 and 31.5 kg P ha−1, respectively.