Journal of applied ichthyology-zeitschrift fur angewandte ichthyologie vol:14 issue:3-4 pages:251-257
A gonadoliberin analogue (GnRHa) whose biological role is the stimulation of gonadotropin (GTH II) secretion, has been encapsulated together with intestinal absorption enhancers and proteolytic enzyme inhibitors. The capsules have been coated to prevent their solubilization at acid pH in the stomach. After oral delivery of the capsules by forced-feeding, high GnRHa intestinal absorption and high bioavailability in the blood results. GTH II secretion was stimulated in a dose-dependent manner by the orally delivered GnRHa in three species having different digestive tract structures and different feeding habits: the rainbow trout, the common carp and the African catfish. In addition, the oral delivery of GnRHa also results in the induction of ovulation in all three species at doses similar to those usually used to induce spawning in these species. There was no competition of nutrient given together with the microcapsules on GnRHa absorption. From these results, it becomes possible to develop special diets containing microencapsulated bioactive peptides for use in therapy or to modify nonvital functions in fish. In the present case, an orally-induced ovulation treatment will be developed.