Yeast products for healthy pets

Yeasts are becoming a common ingredient in livestock diets, because of their beneficial properties. Yeasts are known to help optimise the actions of the gut microflora, improve defence and resistance to oxidative stress and support the general immune system for example. All of these properties are not only seeked for in livestock (food producing) animals, also pets can benefit. At the same time, pet owners are more and more concerned about the general well-being of their dog or cat. Over the last decades, a lot of research and development has therefore been done in looking for certain nutrients that can help promote animal health and well-being. This growing trend was the reason Lallemand Animal Nutrition organised its first international pet food seminar to delve deeper into the effects of microbial solutions for pets. Lallemand also has a range of feed ingredients for use in pet food.

More good bacteria and IgG

During the seminar, a list of speakers updated the audience on the benefits of certain feed ingredients in pet food. In this review we highlight a few of them. One of the speakers was Prof Giacomo Biagi from the University of Bologna, Italy. Biagi spoke about the gut microbiota and the immune response and the nutritional strategies to reinforce the pets’ natural defences. “Some studies have been done with probiotics in pet food showing positive effects on the immune system. However, the number of studies is limited and only a very few probiotic bacteria are authorised in Europe for use in pet food’, Biagi explained. For dogs, the probiotics Oralin (Enterococcus faecium 4b1707) and Calsporin (Bacillus subtilis C-3102) are examples that are authorised to be used in the European Union (EU). Yeasts are also known to have probiotics effects, but currently no live yeasts are allowed to be used in pet food in the EU, but inactivated (dead) yeasts are allowed. Professor Biagi’s team recently conducted a study to evaluate the effects of an association of yeast fractions from different inactivated yeast strains* on the intestinal ecosystem of adult healthy dogs. The trial involved an in vitro part, whereby the yeast derivative was incubated with canine faecal inoculum, and an in vivo trial involving 16 adult dogs (fed yeast or control diet). Dog faeces was analysed at three and four weeks into the trial. The results indicate benefits of the yeast derivatives on the dogs’ gut microbiota. The in vitro analysis shows higher levels of Lactobacilli and Bifodobacteria as well as a lower pH with the yeast derivative. The tested yeast product also had a positive effect on the dogs’ natural defences, reflected in a higher level of IgA antibodies detected in the faeces of dogs.

Not all yeasts are the same

Yeast has been part of human diet since thousands of years: just think of bread and winemaking, said Dr Francesca Susca from Lallemand Animal Nutrition, Italy. “And not all yeasts are the same. They can differ in structure, composition and function and that depends on the strain. The aim of researchers is to find and select the strains that have the best adhesive properties,” she addressed. Dr Susca focused on the various forms of yeast. “There is the live yeast, which can be added to animal feed for their probiotic effects. Then there are the inactive yeast (killed yeast cells), used as flavour enhancers or as a natural source of nutrients such as B vitamins, amino acids and minerals (there are also for example selenium enriched yeast products on the markets). The inactivated yeast can then be separated into two different fractions: The yeast extracts, i.e. the soluble fraction of the inactive yeast, comprised of more than 60% proteins. They represent a valuable source of proteins, nutrients and minerals and can also be used as natural flavour enhancers and palatants in pet food. The second fraction is the yeast cell wall, rich in beta-glucans and mannan oligo saccharides, which are well known for their pathogen-binding and immune-modulation activities. They can contribute to pet microbiota balance and digestive well-being,” Susca explained. She also touched on a new product*, combining inactivated yeast fractions from three different strains.” Each strain is produced using a dedicated processes and the strains selected and combined provides a superior binding capacity and a synergistic, broad and balanced immune modulation.”

The regulatory guidelines

The science and the development of new pet food ingredients are key, but translating this to an actual commercial product comes with proper labelling and working with the regulatory guidelines. At the seminar, Dr Davide Galaverna, pet food technology and regulatory specialist from Italy explained a bit more on how to label and claim yeast and yeast derivatives products. How to translate the science into marketing and product labels for pet food? Galaverna updated the audience on the current European legislation when it comes to labelling, differentiating mandatory information (nutritional, composition, dosage, etc.) versus voluntary information, such as functional claims. “We are dealing with mandatory information / elements that we can put on the pet food package and the voluntary information. The main objective of the regulation regarding the mandatory information is to protect the consumer and avoid misleading messages,” Galaverma said. “Depending on the nature of the product, different rules apply. Inactivated yeast and yeast derivatives are feed materials (regulation 767/2009), while live yeast, and live microorganisms in general, are feed additives (regulation 1831/2003) and require pre-market approval. Within the feed additives regulation, in the category ‘zootechnical additives’, the following functional groups are included: (a) digestibility enhancers: substances which, when fed to animals, increase the digestibility of the diet, through action on target feed materials an d(b) gut flora stabilisers: micro-organisms or other chemically defined substances, which, when fed to animals, have a positive effect on the gut flora. This means that live yeast and live microorganisms can be authorised in one of these two functional groups. So far, no live yeast is authorised for use in pet food in the European Union,” he explained.

*Yang