January 2015: Who needs a New Year’s resolution?

The time of feast and overindulgence may have gone and the subsequent and inevitable resolution to eat better and take more exercise is upon us. So, fat . . . is it all bad?

The answer is, of course, no. Without certain fats we wouldn’t survive, or at least we would become extremely unwell. The pig is no different and we have to consider in particular the “essential” fats – the ones that the body can’t synthesise for itself and that are required for various biological processes.

The principle essential oil for pigs is linoleic acid, which is an Omega-6 acid because the first double bond (carbon-to-carbon) is situated on the sixth carbon atom in the molecular chain of 18 carbon atoms long. All very scientific and interesting I’m sure, but where does it come from and what does it do?

For our purposes, soya oil is the most cost-effective source of linoleic acid, owing to the volumes produced. The plant that produces the highest level of linoleic acid is the dwarf saltwort from Mexico. It can have up to 79% linoleic acid in its oil and grows in desert and salty conditions, so is becoming an interesting arable crop for more challenged regions.

The body takes the linoleic acid and converts it through desaturation (adding more double bonds from carbon to carbon) and elongation (adding more carbons to the molecule) to become a biologically active product such as arachidonic acid. This is vitally important for muscle brain and liver function, as it’s involved in cellular signalling. But it’s particularly important as one of the prostaglandin building blocks. Prostaglandins are vital chemicals involved in controlling muscle movement.

The information on recommended levels of linoleic acid in pigs is limited, but between 1% and 2% would be normal. Too little can lead to problems, but too much linoleic acid in the diet is a threat to the pig. This is because it could lead to hyper inflammation and over-reaction to certain physical and pathogenic challenges.

Omega-3 fats found in fish oils are the most effective way to balance high levels of linoleic acid. They work by offsetting the Omega-6 fats in tissues, resulting in more appropriate and controlled reaction and inflammation. They are also vital in brain and muscle function, as they’re so prevalent in nerve cells and function, but in this case they simply moderate the response brought about from potentially excess omega-6 fats.

A common example of hyper-inflammation or over-reaction can be found in humans. With the quantity of omega-3s in our diet reducing, through lower fish consumption, levels of allergic response to hayfever, dust and pets, have increased. This has, in part, been attributed to the imbalance of omega-6 and omega-3s in the human diet.

The same can be true of pigs – particularly young pigs at weaning that can suffer from inflammation in the digestive tract as they move onto solid feeds. Linoleic acid is an essential oil, but awareness needs to be maintained of potential excess.

> Dr Phil Baynes has spent his career in pig welfare and nutrition. Based in Cheshire, he runs Baynes Nutrition and is a consultant nutritionist to Provimi

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