I think you can try using trizol for RNA extraction.

We extract RNA from swine liver using Trizol, works very well... we screen for presence of a specific infectious virus. However, If you will investigate for specific animal tissue RNA (expression) they may be altered or even unrecoverable.

In my experience, getting a quality assessment of RNA purified within just 2 hours after sacrificing a mouse showed there was already degradation in the 16S rRNA. If you have the equipment it may still be worth a try. Maybe try using Qiagen's RNeasy kit for a consistent extraction among samples.

For RNA work, you'll have to take samples from the carcasses at the time of slaughter.

There was some work done here years ago looking at collecting muscle tissue samples soon after slaughter (~15 minutes) to several days after slaughter in meat processing plants for expression array experiments (aka typically chilled to ~4C). My memory was how surprised people were at little change there was with extended times post slaughter. I do know they were culturing viable fibroblasts out of them after 24 hours. From memory the work was not published so just take this as background information that you need to check.

Thank you so much for your input.

So I still am able to have hope, at the same time I dont have to get my hopes up.

I will try to check RNA quality using Agilent Bioanalyzer to see how those get degraded in my experimental condition.

Thanks again,

Masaaki

mirVana kit from Ambion (life technologies) works well with most extractions; I tend to immediately put my tissue in their lysis buffer which helps preserve the RNA. Tissue can be stored in this buffer at -80C; I have stored it for as long as 6-8 months and obtained good quality RNA.

In my experience, we snap froze our samples in liquid nitrogen at the time of necropsy and stored at -80 if needed until the time of extraction. We extracted great quality RNA similar to others' comments, with Trizol. Another poster mentioned checking the quality with an Agilent Bioanalyzer and we do that also.

Hope it goes well for you,

Cheers

Hi. I have experience with RNA isolation from soft and hard tissues both of them preserved in RNAlater at -80ºC. I used Trizol method.

The step you need to care is homogenization: we do it by mashing the tissue with homogenizer sticks (like this one: http://www.zymoresearch.com/media/images/products/H1001L.jpg) and then used a blender. It is important to mash the tissue with the sticks so you do not lose any piece in the blender.

Hope it helps.

Celia

From my experiences, I would be very cautious collecting samples that many days postmortem. If you search the literature, there will be varying reports of the amount of degradation that takes place postmortem. Degradation will be dependent upon which tissue you are trying to collect RNA from and even which genes you are interested in. There is a student in my master's lab that extracted RNA from pork adipose tissue at varying times postmortem (immediately after exsanguination to six days postmortem) and found differences in degradation of different genes. Some of her genes of interest showed no change for up to one day postmortem while others showed degradation issues at 5 hours postmortem. Her abstract is here: https://asas.confex.com/asas/mw14/webprogram/Paper3026.html

She hasn't published the full paper yet. 

So, even if you extract intact RNA, be aware that your genes of interest might still have degradation issues. If at all possible, I suggest you start with fresher tissue, but I understand that might not be possible. 

Good luck,

Jennifer

Thank you Jennifer for the information.

I realized that is what I would like to know.

At first I wanted to collect fresh animal samples from carcass right after slaughter. But it is not possible in my situation.  Just now I found a paper published by Bahar et al 2007 in BMC Mol biol. Jennifer, your information and the paper encouraged me to go get carcass samples for further analyses.

I would also thank you all for spending time to provide me with the information from your experiences.

Masaaki