EFFECTS OF PEA STARCH YEAST FERMENTATION ON GLYCEMIC INDEX, PALATABILITY, METABOLIC STATUS AND INTESTINAL HEALTH OF DOGS AND CATS FED A PEA BASED DIET

Abstract

The premium pet food market has expanded substantially over the past few years, which is related to the growing pet owners concerns with animals welfare and longevity. To address this new market niche, the pet food industry invested in ingredients and formulations that aim to provide health benefits for dogs and cats. Among these new ingredients are peas. Peas are low glycemic index carbohydrates that have become popular in pet food formulation. Despite evidence showing that peas benefit pets metabolic status,the use of peas in cat food formulation still a challenge as cats tend to refuse the taste of pea based diets. Fermentation is a millenary technique used to improve food flavour and texture. Among the microbes used to ferment food are yeasts. Yeast fermentation yields amino acids that are potent flavour enhancers. Furthermore, yeast fermentation lowers the levels of antinutrients, which may inhibit the bitter taste of peas. In addition, the yeast cell wall contains prebiotics that might benefit intestinal health. The purpose of this thesis was to create a novel pet food using yeast fermented pea starch and to investigate the effects of this diet on palatability, glycemic index and intestinal health of dogs and cats. To research these objectives, four studies were conducted. The first study describes the methodology used to ferment the pea starch and compares pea starch composition before and after being fermented. The second study investigates whether yeast fermentation impacts dogs and cats postprandial glucose response to unfermented and fermented pea starches and diets. The third study investigates whether fermentation enhances the palatability of pea based diets formulated for dogs and cats. The last study investigates whether dogs and cats metabolic status and intestinal health benefits from diets formulated with unfermented and fermented pea starch over a diet formulated with a more traditional carbohydrate source (namely corn). Besides showing that pea starch can successfully be fermented using a common yeast used in human food processing (C. utilis), the results of the first study show that pea starch fermentation slightly increases protein and crude fibre content. The second study reveals that fermentation does not significantly impact dogs and cats glucose response to pea products (starch or diet). The third study results show that dogs and cats have preference for a diet formulated with fermented pea starch over a diet formulated with unfermented pea starch. The results of the last study show that dogs and cats fed peas instead of corn have improved metabolic status (regardless of fermentation). Moreover, when compared to a diet formulated with corn, consumption of pea based diets led to a more diverse bacterial intestinal community and increased population of Faecalibacterium, genera often associated with improved intestinal health. In conclusion, the results of this thesis show that yeast fermentation improves the palatability of pea based diets without compromising the health benefits associated with the consumption of peas in dogs and cats.