- Posted on March 15, 2013 6:45 pm
Today’s Diary Entry is sponsored by Spikes World Wildlife Food
Another Friday, this one marking the end of week 5, its amazing how fast time is going and how little it feels I have achieved. Every spare moment I get is going into finishing Emergency First Aid for Animals, when I sat down and started this I had no clue how big the task would actually be. I am a perfectionist however I also realise that sometimes it’s is a case of balancing perfection with getting things done – in this instance however I am taking the route of caution to make sure that I can back up everything in the book with solid medical fact to ensure the best outcome for cases that follow it.
Anyways onto today, we spent nutrition today looking at the crude fat portion of feed, this is commonly thought of as the fat portion of the sample. This however is a gross simplification as in fact this portion contains organic acids (Essential Fatty Acids), oils, alcohols and the important fat soluble vitamins. Fats are important within the body as they act as electron carriers, substrate carriers in enzymatic reactions, components of biological membranes and as stores of energy.
In fact in obese animals around 97% of adipose tissue is composed of fat storing energy, lipids also help give structure to muscle and have an impact on cholesterol.
Now the fat potion of the sample is solvent soluble, so the sample is continuously extracted using diethyl ether which dissolves the fat in the sample. Using the apparatus in the image above the ether is in the bottom beaker (which is weighed when it is empty) which is heated, it then evaporates as gas before the condenser (at the top) cools it and it collects as liquid in the middle sample chamber. It stays in the sample chamber (in the middle with the paper sample filter) until it reaches a critical level it then it is returned to the bottom beaker. This process is repeated for around 6 hours or overnight to ensure all the fat is dissolved in the solvent. Once this is done the sample chamber is removed and the ether collected to be reused and removed by distillation – when a miniscule amount remains the bottom beaker is then dried in a vacuum oven and cooled in a desiccator. The bottom beaker is then weighed and the difference in the new weight – the starting weight is the amount of crude fat in the sample.Posted in categories: Vet School Diary