Fibre in Animal Nutrition: Analysis and Optimisation of Feed

We’ve all seen advertisements for breakfasts ‘rich in fibre’ and been advised that it’s good for pets’ dietary health (as well as our own!). But why is dietary fibre a necessary part of an animal’s diet and why can too much or too little cause issues?

What is Dietary Fibre?

Unlike the fibres that make up carbon-fibre and ultra-high-molecular-weight polyethylene, dietary fibre (or roughage) is natural and is the portion of plant-derived food that is indigestible. This means that it can pass through both the stomach and small intestine, intact and unchanged, as a complex carbohydrate.

Once dietary fibre reaches the large intestine, gut microbiota (organisms within the digestive tract) can begin fermenting the fibre into gases and physiologically active by-products, the most common being short-chain fatty acids. A diet containing regular and substantial dietary fibre is linked with maintaining optimum levels of good bacteria and promoting gut health as well as reducing associated disease. It also encourages the development of healthy stools (not to sit on!) and increases the regularity of passage. Good sources of dietary fibre include fruits, vegetables, legumes, cereals and nuts.

Classifying Fibre

When it comes to dietary fibre, it has historically been classified based on two factors; solubility (the ability to dissolve in a solvent) and fermentability (the ability for gut flora to break down the fibre in the large intestine).

Rapid/highly fermentable fibre: Known for producing more short chain fatty-acid by products (SCFABP) and gas that compared to slowly fermentable fibre. The SCFABP are important for cell health within the large intestine. The higher production of gas means that this type of dietary fibre can, in excess, lead to increased flatulence and bloating!

Slowly fermentable fibre: Important as a stool bulking agent, as they are far more resistant to breakdown within the large intestine and keep their structure for longer. This increases faecal bulk, which is known to benefit treatment of certain digestive diseases, such as constipation and inflammatory bowel disease.

Solubility of fibre: All fibre to some degree can hold water, but more soluble fibres have a greater water holding capacity.  The more soluble the fibre, generally the more easily it is broken down and this can lead to similar outcomes/effects of highly fermentable fibre. Most dietary sources of fibre contain a mixture of both soluble and insoluble fibre.

Fibre as Food

Another way of classifying dietary fibre is as a prebiotic. As previously mentioned, the addition of dietary fibre can increase and maintain the optimum level of beneficial organisms within the large bowel. This is because the fibre passes undigested through the small intestine, so can act as a substrate (surface where an organism can live) for the organisms, stimulating propagation and growth!

A good example of this is Fructooligosaccharides (FOS), which can be found naturally in many plants such as garlic, onion, asparagus and bananas. As FOS are composed of numerous short fructose chains, they are subtly sweet, and can be used as a replacement for artificial sweeteners.

Fibre in the Lab

It’s clear that both the amount and type of fibre contained within pet food and animal feed have an impact on digestibility, the amount of nutrients digested and absorbed through consumption. Therefore, it’s critical that laboratory analysis is employed to accurately determine dietary fibre within products to maximise the impact and health benefits of animal food products.

We at a1-envirosciences are proud the be the UK distributor of the VELP range of innovative fibre analysers. This includes both the VELP FIWE 3 and FIWE 6, which are designed to simplify and speed up the process (over 3x faster than conventional methods) of raw fibre extraction. This is perfect for a variety of applications, including the Weende method to ascertain crude fibre concentration of a sample, as well as NDF (the modern-day gold standard), ADF and ADL determination.

We also offer the VELP FIWA Advance Automatic Fibre analyser, which is fully automatic for both crude and detergent fibre determination. This guarantees consistency for the previously mentioned methods and requires only 2 minutes of operator time! Why wouldn’t you want rapid analysis, high reproducibility and reliable results? All with minimal interaction required, giving you more time to focus on other analyses.


Fibre continues to be a very important building block in all diets from humans to pets and livestock. By balancing both the type and amount of dietary fibre, it is possible to maximise gastrointestinal health, fullness and digestibility. This can also mean that, within pet food and animal feed, correct proportions of dietary fibre can aid in weight management and treat diabetes mellitus, constipation and diarrhoea.

If you’re wanting to take your fibre analysis to the next level and are interested in learning more about the VELP range, give us a call on 0845 873 8181 or reach us by email:

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