Piglets can secrete acidic mammalian chitinase from the pre weaning stage.

Fishmeal substitutes (such as insect-based feeds) in pig diets can promote sustainable pork production. Insect powders contain chitin, a nitrogen-containing indigestible material, and pigs must have the capacity to secrete chitin-degrading enzymes to benefit from these diets. The chitin-degrading enzyme (acidic mammalian chitinase; AMCase) and its gene expression have been detected in the stomach tissue of approximately 6-month-old fattening pigs; however, it remains unclear from which stage chitin-degrading enzymes are secreted. In the present study, the stomach tissue of piglets was collected from the suckling stage (14 d old) to 56 d to evaluate chitin-degrading enzymes and associated gene expression. AMCase mRNA and protein expression was detected in the stomach tissue of all piglets from days 14 to 56. AMCase secretion might increase with the increase in stomach tissue weight as piglets grow. Insect powders can therefore be used in the diets of pre-weaning piglets. The gastric AMCase level was approximately 30% that of fattening pigs. The appropriate inclusion of insect meals in the diets of pigs at different growth stages still needs to be determined.