The Effect of the Duration of Feeding a Diet Containing Cuban Cricket (Gryllus assimilis) Meal on Fecal Bacterial Enzyme Activity and Nutrient Digestibility in Adult Rabbits

Insect-derived feed ingredients are increasingly considered alternative protein sources, but their time-dependent effects on digestive function remain unclear. This study evaluated how the duration of feeding a diet containing Cuban cricket meal (CCM) affected fecal bacterial enzyme activity and apparent nutrient digestibility in adult rabbits. Thirty-two New Zealand White male rabbits were allocated to four groups. The control group received a diet containing 14% soybean meal throughout the six-week trial, whereas experimental groups received soybean meal followed by a diet in which 10% CCM replaced soybean meal for the final two, four, or six weeks. It was found that the fecal enzymatic response depended on feeding duration. Short-term feeding induced limited changes, whereas longer feeding periods (four and six weeks) increased the activity of enzymes involved in the degradation of complex substrates, including chitin, and enhanced the extracellular activity of several enzymes. Digestibility of dry matter, crude protein, ether extract, and energy was unaffected. By contrast, neutral detergent fiber, acid detergent fiber, and acid detergent lignin digestibility increased after four and six weeks (p < 0.001). These results could be interpreted as indirect evidence that rabbits’ gut microbiota requires an adaptation period to effectively respond to insect-derived components.