Yeast and yeast derivative products are versatile and natural ingredients to keep in mind when formulating food for pets. They can be used for everything from a palatability enhancer to a source of nutrients and functional ingredients.
This article focuses on the characteristics and benefits of a new ingredient for petfood: a specifically designed functional hydrolysed yeast.
Yeasts have been part of the human diet since at least ancient Egypt when they were already used to leaven bread and ferment wine. Their exceptional fermentative and nutritional properties also make yeasts valuable nutrients for animals. Not all yeasts are equal. There are about 60 genera and about 1500 species of yeasts. Only a few are used commercially.
Saccharomyces cerevisiae is the main yeast used in food, beverage and baking as well as in animal nutrition. Yeast in animal feed is either used live (probiotics) or inactivated. There are different types of yeast products: whole-cell inactivated yeasts, autolysed yeasts, hydrolysed yeasts and yeast extracts, each with its own production process and nutritional properties (figure 1).
In the case of whole-cell inactivated yeasts, yeast are heat inactivated, but there is no lysing step. The final product will have a low nutrients digestibility and functionality. For autolysed yeast, the yeast cells are partially lysed by endogenous enzymes, which enhances the digestibility compared to a basic inactivated dried yeast. However, this autolysis process is less controlled than a hydrolysis.
The production of hydrolysed yeast involves the addition of specifically selected enzymes. These are chosen to orient and control the lysis, ensuring a specific level of functional ingredients and a consistent batch to batch product composition. This is why yeast company Lallemand has focused on the screening of different feed-grade yeast biomasses and on the optimisation of their production processes in order to introduce to the market a specifically designed functional hydrolysed yeast for animal feed: ‘Yela Prosecure’.
To create this product, a controlled hydrolysis process is applied with the addition of specifically selected exogenous enzymes to the selected biomass, ensuring high nutrient digestibility and functionality while providing reliability in terms quality and availability of appropriate volumes.
The hydrolysed yeast Yela Prosecure is a feed material (Regulation (EU) No 68/2013) allows nutritionists 1) to diversify the protein sources in the diet while 2) bringing functional properties and enhancing palatability.
Mode of action
The product provides functional nutrients with dual action: in the upper gut and in the hindgut. In the upper gut, the hydrolysed yeast provides highly digestible proteins which offer a high level of free digestible amino acids with an early and fast absorption kinetic.
This was demonstrated through in vitro kinetic studies comparing the digestibility of Yela Prosecure to different feed protein raw materials (such as soybean meal, fishmeal, potato protein) as well as other types of yeast-based products (inactive dry yeast and autolyzed yeast) (fig. 2).
This advantage is related to the specificity of the production process, showing the importance of a controlled hydrolysis which makes proteins more accessible, having been lysed into free functional amino acids and small peptides that are readily and directly absorbed.
Once it reaches the hindgut, the remaining part of the hydrolysed yeast consists mostly of fermentable insoluble carbohydrates inducing a late energy release supporting fibrolytic microbial populations leading to an improvement of microbial diversity and activity, with a release of valuable short chain fatty acids (SCFAs), such as butyrate, and a decrease in proteolytic microbial compounds production, like ammonia.=
Palatability trials in dogs have shown the potential of Yela Prosecure to enhance petfood palatability (figure 3), likely related to the high natural content in glutamic acid.
High quality & highly absorbable nutrients
Yeast is a formidable bioengineering factory and a source of valuable nutrients and functional molecules. Hydrolysed yeast produced with an optimal lysis process enables formulators to take maximum advantage of these nutritional and functional properties.
They can support digestive care and enhance petfood palatability while contributing to the protein balance in a context of partial substitution of conventional protein sources.
Article contributed by Francesca Susca, DVM, PhD, Pet Development Manager Lallemand Animal Nutrition, Canada.