Is chitin an interesting fibre source for cats? Effects on palatability, digestibility, and health markers

Abstract The effects of dietary inclusion of mechanically separated yellow mealworm ( Tenebrio molitor ) exoskeleton, a chitin-rich insect-derived fibre-fraction, in feline diets were evaluated. Palatability, digestibility, and health parameters were assessed. In a crossover design involving ten adult cats (2 years; 3.97 ± 0.52 kg), two diets containing either 5% lignocellulose or 14% yellow mealworm exoskeleton were fed for 28 days, preceded by a 3-day two-bowl palatability test. Inclusion levels selected achieved replacement of 3.2% of cellulose (control) with chitin (test). Protein content was adjusted to maintain isocaloric balance between diets. Kibble characteristics showed higher density, lower expansion, lower water activity and lower hardness for the test diet ( ). There were no adverse impacts on palatability or food intake. Apparent digestibility revealed reduced crude protein digestibility ( ) in the test group, but higher than control when correcting for chitin-bound nitrogen ( ). Dry matter, organic matter, crude fibre ( ), and nitrogen-free extract ( ) digestibility were higher in the test group. Additionally, lower faecal dry matter was noticed for the test diet ( ), without faecal consistency changes. Haematology and biochemistry remained within reference intervals, and no differences were observed. Plasma fatty acids largely mirrored dietary composition (lower arachidonic acid ( ) and omega-3 fatty acids ( ) in the test group). Body weight and body condition score were unaffected, and all cats remained healthy throughout the trial. These findings support the use of chitin as species-appropriate ingredients/fibres in feline diets.