Mealworm-fiber

Their benefits in pet food applications

by Bénédicte Lorrette, Animal Nutrition & Health R&D Director and Lorena Sanchez, Scientific Project Manager, Sprÿng, France

hat you feed your pet has a direct impact on their health. It is important to provide them with what they need and want. The key is having a well-rounded, balanced, and high-quality diet which contains proteins, vitamins, minerals, but also fibers. Too often neglected, adding dietary fibers to pets’ daily rations can in fact improve their wellbeing and provide some valuable health benefits. Fibers, from mealworm, in the form of chitin, are proving to be particularly interesting for pet food diets.

Mealworms are a natural source of fibers

Because dietary fibers are not one compound, they can be difficult to define. The World Health Organization characterises them as all carbohydrates with a certain degree of polymerisation that are neither digested nor absorbed in the small intestine. Globally two types of beneficial fibers exist, the soluble ones and the insoluble ones. The most common sources of fibers in a diet are usually

Wcoming from plants and are found in fruits, vegetables, whole grains, beans, and pulses.

Fibers are not digested and pass through the intestine unchanged. Insoluble fibers are generally highly tolerated even in quantity. They play an important role stimulating movement in the large intestine, making stools easier to form and pass, preventing constipation. Soluble fibers on the other hand, absorb water, forming a gel-like substance, and act as a food source for gut bacteria that aid digestion. They have also been linked to glycemic control.

In nature, fibers are rarely found in animals. Low in energy supply, while also known to improve well-being, and provide certain health benefits (obesity control, digestion, anti-hairball, etc.), the petfood sector often likes to include fibers in recipes in the form of beet pulp, chicory, and legumes . But an interesting new animal alternative has emerged: mealworm-based fibers.

“Mealworms are a natural source of animal fiber. Just like most crustaceans and other insects, they contain in their exoskeleton or cuticle insoluble fibers called chitin, that closely resemble the cellulose polymer in terms of chemical structure and property,” explains Bénédicte Lorrette, Animal Nutrition & Health R&D Director at Sprÿng. “Our protein ingredients made of mealworms processed with their cuticle, our dry protein concentrate Protein70 (Total fibres 8%) and our slurry WetPro15 (1-2% of total fibres), are a unique source of high-quality animal protein containing a low but significant amount of natural fibres. This makes them different from the conventional animal protein sources used in pet food which don’t contain fibres, and more akin to certain vegetable protein sources.”

The health benefits of chitin

Chitin is an insoluble fiber that rarely exists in a pure form in nature but instead is usually in a complex matrix with proteins, lipids and minerals. Nested proteins can be found intertwined within the nitrogenous polysaccharide polymer.

“Our mealworm ingredients are known to be a source of highquality proteins for pets, but also supplements the recipe with fibers (chitin), which have to be taken into consideration in the final diet formulation,” details Lorena Sanchez Scientific Project Manager at Sprÿng. Historically, fibers have been used to improve digestive health and transit, optimise stool quality, and promote weight management and control by diluting calories. And indeed, feeding cats and dogs with 30% of Protein70 in the diet (1.8% chitin in the kibble) for 6 months resulted in excellent faeces consistency (moist and formed). More recently chitin, chitin has been shown to play a role in the digestive health and the management of various disorders.

How much fiber is in our mealworm ingredients?

“It is important to quantify chitin to properly use it in pet food formulations,” explains Bénédicte Lorrette. “Today however, the methods to determine the amount of chitin in a product are not harmonised. There are a panel of methods used for fibers determination (total dietary fiber, insoluble fiber, neutral fiber, etc.) mainly developed for plant-based matrixes and food applications but no one is specific to chitin. Like others confronted with the same problematic, at Sprÿng, we worked on finding the most appropriate analytical method to quantify as accurately as possible the matrix of our ingredients.”

As previously mentioned, chitin rarely exists in a pure form and is usually found in a complex with other compounds from insect cuticles (proteins, fats, ashes, pigments), making its extraction complex. The method developed for fibers analyses on plant-based material also quantifies these proteins, ashes and other residual insect molecules, leading to an overestimation of the chitin content. A great deal of work is still underway to determine the most appropriate and specific analysis method for chitin.

It would appear that the best compromise and the most suitable method for determining chitin in insects is the ADF-ADL method proposed by Hahn et al. 2018. The correction of the ADF measurement by the detergent lignin (ADL), rectifies this overestimation. It is also possible to determine chitin content in insects by successive chemical extractions (at high acid and base concentrations), leading to a purified solid residue. These methods may appear more specific, but they are time-consuming and lead to very large volumes of effluent.

For instance, chitin seems to have a cholesterol lowering effect. It binds cholesterol, hence decreasing its absorption and leading to the excretion of excess cholesterol. Acting on the gut microbiome, dietary supplementation with mealworms’ cuticles can also improve liver health and protect from liver steatosis by decreasing the generation of proinflammatory lipids and hepatic inflammation. Indeed, obese rodents fed with mealworm cuticles showed a lipid lowering effect (30%), especially in the liver, linked to the proliferation of beneficial bacteria. Through its impact on the microbiota, chitin also seems to play an important role in maintaining intestinal mucosal homeostasis and improving intestinal barrier function.

However, like most fibers, chitin can also be considered an antinutritional factor. Its binding capacity may reduce the availability of certain minerals, and micronutrients within a food matrix. The nature and amount of dietary fiber can impact gut health and function both ways, it is a question of balance between too much and not enough fibers. As with any other component of a recipe, the dosage needs to be controlled and adequate.

Chitin remains an insoluble fiber that, as all fibers, requires an adequate dosage, that does not affect digestibility, while providing beneficial effects. Correct measurements of chitin levels means that our ingredients rich in protein can be used in pet food recipes and formulation, with all the benefits of fibers and none of the disadvantages. With our mealworm-based ingredients, the industry can feel secure in trusting a natural, premium product highly digestible which contains an important protein content and a unique animal fiber.