Pet food containing pre- and probiotics
Providing pets with probiotics on a daily basis has several health benefits. Probiotics have proven helpful in providing preventative and supportive care for both humans and pets (Tuohy et al. 2003, Wynn 2009, Veir et al. 2007 and Wlodzimierz et al. 2005). Probiotics are useful both in the prophylactic approach to antibiotic-associated diarrhoea and in the treatment of diarrhoea induced by antibiotic treatment (Shah 2007 and Benyacoub et al., 2002). Other studies have shown positive effects on the immune system (Benyacoub et al. 2002).
Probiotics
Probiotics are defined as: “a live microbial feed supplement which beneficially affects the host animal by improving its intestinal microbial balance” (Fuller 1989). Already present in the intestinal system of all animals and humans, probiotics are necessary for the digestion of nutrients and the balance of the intestinal microflora. Since 70 % of the immune system originates in the digestive tract a balanced microbial ecosystem is crucial for optimal health (Suchodolski and Simpson 2013 and Vighi et al. 2008).
Depending on the strain of bacteria, probiotics have several possible modes of action:
- Competition for nutrients and adhesion sites
- Alteration of the microbial metabolism
- Stimulation of the immune system
- Direct antimicrobial effect
(Fuller 1989 and Shah 2007)
Probiotic supplements must be non-pathogenic, non-toxic and not be able to transfer antibiotic resistance but be able to maintain genetic stability (Grajek et al. 2005). In order to reach the intestinal tract in adequate numbers, probiotics must be able to survive transit time through the acidic environment of the stomach and persist in the presence of bile (Marcinakova et al. 2006).
Prebiotics
Prebiotics are defined as: “a non-digestible food source that beneficially affects the host by selectively stimulating the growth and/or activity of one or a limited number of bacteria in the colon, and thus improves host health”. For a food ingredient to be classified as a prebiotic it must be:
- Neither hydrolysed nor absorbed in the upper part of the intestinal tract.
- A selective nutritional source for the non-pathogenic bacteria, stimulating the growth and/or activity of those microorganisms.
- Stimulating local or systemic effects beneficial to the host health.
- Able to promote a healthier composition of the colonic microflora.
(Gibson and Roberfroid 1995)
Most prebiotics used in pet-food are non-digestible carbohydrates such as inulin. These complex carbohydrates are able to resist the stomach acid and therefore reach the large intestines intact, where probiotic bacteria ferment them. Prebiotics also help to reduce pH in the large intestine because of the production of fatty acids, thus promoting the growth of probiotics (Gibson and Roberfroid 1995 and Wynn 2009).
Pet food containing pre- and probiotics
Based on the growing awareness of probiotics and their health benefits, a new group of pet foods has emerged – so-called functional foods. Functional foods are defined as: “foods that contain some health-promoting components beyond traditional nutrients” (Shah 2007). Functional foods are consumed as part of a normal everyday diet and are not classified as supplements (Grajek et al. 2005). One way to modify foods to become functional is by adding probiotics (Shah 2007).
When providing nutritional supplements for pets, compliance is important. Thus, many manufactures are producing pet foods containing probiotics. Since probiotics are not drugs, there are fewer regulations regarding their use as supplements and food additives. Various studies are reporting poor quality control with probiotic products. A significant percentage of products does either not contain the organisms or the number of organisms stated on the label, or they contain additional species (Weese and Arroyo 2003). Based on several tests and studies there seem to be a great difference in the quality of probiotic pet foods (Weese and Arroyo 2003 and Kazarjan et al. 2012).
The focus on preventative healthcare and probiotics, in general, will continue to grow, which means more products will emerge. Probiotics improve general health in animals but are especially an advantage for animals exposed to stress, infections, during weaning, illness and old age. Thus, the rationale for adding probiotics to pet foods seems well-justified (Benyacoub 2002). However, it is important to be aware of the quality of the product. More control and regulation is needed for the manufacturing of probiotic products for pets, and especially veterinarians but also pet owners are advised to make available published evidence and experience into account when choosing probiotic diets for pets.
By Therese G. Hosbjerg, DVM and Technical Manager at Bacterfield GMBH
