Biologically active compounds in colostrum: Significance and possibilities for increasing their resorption

Colostrum in domestic animals contains numerous bioactive substances like insulin and insulin-like growth factors (IGF-I and IGF-II), epidermal growth factor (EGF), immunoglobulins (Ig), lactoferin (Lf), transferin (Tf) and others. Many of them have distinct functions and stimulate growth and glucose utilization, or have some other, still unknown regulatory function. Bioactive substances influence growth and development of the gastrointestinal tract (GT), and cause many metabolic and endocrine changes in the neonate. Resorption of the bioactive substances from the GT of the neonate could be a specific, receptor dependant, or nonspecific process, and in many cases the exact mechanism has not been completely elucidated. On the other hand, there are technological procedures and substances that could effectively increase concentration of some bioactive compounds in the systemic circulation of the neonate. We are still unaware of the full importance of these technological procedures and products, partly because of the very complex additive and/or synergic effects of the different bioactive substances from the colostrum on the newborn animals