We all know how important is it to add fibre to our diets. Well, it is true for pooches as well. Here are the FAQs on dietary fibres in dogs.
What is dietary fibre?
The term ‘dietary fibre’ was coined by Hipsley in 1953. Fibre is an essential nutrient required for dog. Scientifically the dietary fibre is defined as edible part of plants, when consumed by dogs, neither they are digested in the stomach nor absorbed in the small intestine but they will undergo complete or partial fermentation in the large intestine. Dietary fibres promote beneficial physiological effects including laxation (easy defecation) and blood cholesterol reduction and blood glucose attenuation.
There are two types of fibre – soluble fibre (dissolves in water) and insoluble fibre (doesn’t dissolve in water) – and both contribute different benefits to dog.
What are the sources of fibre?
Fibre is found only in the cell wall. Since animal cells don’t have cell wall, we can’t expect fibre from animal origin products such as meat, egg, etc. Plants are the only source of fibre.
Grain, starch sources, fruits and vegetable products: Examples: Corn, wheat, oats, barley, potatoes, sweet potatoes, pea flour, brown rice, etc. Among these sources, barley and oats contain higher levels of a type of fibre called beta-glucan. Pet foods containing even small amounts of oats or barley may not be tolerated by some dogs, and can lead to softer and wetter stools or sometime diarrhoea. Wheat middlings, rice bran, bran flakes, cooked oat meal or millet, tomato pomace, dried distiller’s grains, beet pulp, pumpkin pulp, canned pumpkin, citrus pulp, chopped and steamed green beans are some of the fibres tend to increase stool size, but they are less digestible and less palatable. Apple is also very rich in fiber. Make sure to remove the core and the seeds, because the seeds contain bits of cyanide which can be toxic to your dog.
Structural fibres: Examples: Oat hulls, peanut hulls, soybean hulls, rice hulls, etc. Peanut hulls have been used to lower calories in foods. Soybean hulls can do the same thing but lead to high flatulence in dogs.
Isolated fibres: Examples: FOS (Fructooligosaccharides), cellulose, gums, insulin, pectin, etc. FOS has some benefit in the colonic fermentation. Gums have been shown to be both positive and negative in the colon. Cellulose, isolated from trees, is used to reduce hairballs and calories.
What are the health benefits of dietary fibre?
Relieves constipation problem and control diarrhoea: Dietary fibre relieves constipation problem in dogs. The stools will be dry and hard during constipation. When we include dietary fibre, especially insoluble fibre, it will absorb water while moving in the intestine like a sponge. So, the movement of stool inside the intestine becomes easy. It can attract moisture from outside the colon (part of intestine) into a dog’s stool to help promote regular bowel movements. In certain conditions like diarrhoea, if excess fibre is supplemented in the diet, it can absorb excess water from inside the colon to help control diarrhoea. Even if we don’t come across the problem of constipation or diarrhoea, fibre should be there in the diet because it acts as a stool ‘normaliser’. Generally 15-30 gm of fibre supplement per 400 gm of diet is recommended in the case of large bowel diarrhoea. Caution: Although dietary fibre prevents the problem of constipation or diarrhoea, one precaution with the use of fibre for this purpose over the long term is that the hydration status of the dog must be monitored. Hygienic water should be fed to the dog ad libitum. If enough water is not offered, it may lead to the problem of intestinal obstructions, severe constipation, etc.
Reduces blood cholesterol and prevents coronary heart disease: Research over the past several decades has shown that increased consumption of dietary fibres and high fibre foods produces a positive adjustment in levels of serum cholesterol, a biomarker related to the risk of coronary disease. Although, not all fibre and high fibre foods in all studies have exhibited these beneficial properties.
Solves obesity problem: Controlling the food intake may be the best choice to solve obesity problem but it is a complex and multifactorial process. But the concept of using fibre in the diet of dogs is overly simplistic. Adding fibre will help the dogs to lose weight by creating a greater sense of fullness in the stomach. Adding fibre to any dog food ‘dilutes’ its caloric content. So, there are fewer calories per serving that can significantly aid in weight loss. As fibre absorbs water, it expands causing a dog to stop eating sooner because a full stomach signals ‘satiety’ (hunger satisfaction) centre of the nerve system so that dogs feel fuller and consume less energy/calories per meal. A recent study showed that dogs fed with a high fibre diet lost more than five times the fat mass compared to dogs fed with a low fibre diet.
Prevents colon cancer: In a dog’s large intestine, there are varieties of bacteria. Some are good and some are bad. Good bacteria ferment the fibre supplied through diet and creates special ‘short chain fatty acids’ that can help a dog’s colon (part of large intestine) repair itself and prevent cancer. Fibre can help in another way, too. As water is absorbed into the colon, fecal matter swells against the colon wall. This pressure causes muscle contractions which can speed food faster through the digestive tract. This faster ‘transit’ time allows less contact between the colon wall and dangerous cancer-causing substances.
What should be the percentage of fibre in your dog’s diet?
The typical crude fibre concentration in dry pet food is 2.5 – 4.5 percent, according to NRC (National Research Council, USA). The maximum permissible level of crude fibre, according to AFFCO (Association of American Feed Control Officials) recommendation, is four percent in a food containing energy density of 3500 kcal/kg. Caution: Remember not to add too much fibre because your dog may have loose stools instead! Or, he may tend to bloat, or have too much gas in his stomach. If that happens, you should give him regular exercise to reduce the gas.
(Dr HS Madhusudhan, MVSc, PhD, PGDND, is assistant professor at Department of Animal Nutrition, Veterinary College, Hassan, Karnataka).