Lawrence Berkeley National Laboratory

The gut microbiome plays an important role in the health of dogs. Both beneficial microbes and overall diversity can be modulated by diet. Fermentable sources of fiber in particular often increase the abundance of beneficial microbes. Banded crickets (Gryllodes sigillatus) contain the fermentable polysaccharides chitin and chitosan. In addition, crickets are an environmentally sustainable protein source. Considering crickets as a potential source of both novel protein and novel fiber for dogs, four diets ranging from 0% to 24% cricket content were fed to determine their effects on healthy dogs' (n = 32) gut microbiomes. Fecal samples were collected serially at 0, 14, and 29 days, and processed using high-throughput sequencing of 16S rRNA gene PCR amplicons. Microbiomes were generally very similar across all diets at both the phylum and genus level, and alpha and beta diversities did not differ between the various diets at 29 days. A total of 12 ASVs (amplicon sequence variants) from nine genera significantly changed in abundance following the addition of cricket, often in a dose-response fashion with increasing amounts of cricket. A net increase was observed in Catenibacterium, Lachnospiraceae [Ruminococcus], and Faecalitalea, whereas Bacteroides, Faecalibacterium, Lachnospiracaeae NK4A136 group and others decreased in abundance. Similar changes in Catenibacterium and Bacteroides have been associated with gut health benefits in other studies. However, the total magnitude of all changes was small and only a few specific taxa changed in abundance. Overall, we found that diets containing cricket supported the same level of gut microbiome diversity as a standard healthy balanced diet. These results support crickets as a potential healthy, novel food ingredient for dogs.