Stereological evaluation of bovine rumen epithelial and myenteric plexus architecture during pre and postnatal development

• Grant number: 16/03227-4
• Support Opportunities: Scholarships in Brazil - Post-Doctoral
• Start date: May 01, 2016
• End date: April 30, 2019
• Field of knowledge: Agronomical Sciences - Veterinary Medicine
• Principal Investigator: Francisco Javier Hernandez Blazquez
• Grantee: Aliny Antunes Barbosa Lobo Ladd
• Host Institution: Faculdade de Medicina Veterinária e Zootecnia (FMVZ). Universidade de São Paulo (USP). São Paulo , SP, Brazil
• Associated research grant: 15/50095-3 - Expression of proteins of cell communication and cell junctions in the digestive system of cattle fetuses, newborn calves and adult cattle, AP.TEM

Abstract

The rumen and its lining epithelium undergo various physiological and morphological adaptations that prepare them for their duties of bacterial fermentation chamber and absorption of volatile fatty acids, when starting the rumination process. The rumen epithelium is crucial to the digestive and physiological adaptations of the adult feeding ruminants, but the cellular process of adaptation and the most important molecules in epithelial architecture have been little studied. It is known that the epithelium undergoes changes since its embryonic formation until its maturity after weaning, moving from one afuncional state to a functional state, but not yet fully known cellular mechanisms that govern these changes. The myenteric plexus is involved in reflex and integrative activities of digestive aid system. The ganglia of the myenteric plexus lying between the two muscle layers (inner circular and outer longitudinal) forming a network of nervous tissue, specialized highly functional as well as structurally extending without interruption from the esophagus into the anal canal. In addition to the changes in the ruminal mucosa, there is a neuroplastic adaptation of the myenteric plexus rumen associated with the drastic change of power that affect the motility of this body. This motility is different from other parts of the gastrointestinal tract, and the rumen first afuncional in neonates but becoming responsible for the mixture intake in the adult. This biological phenomenon underlies the importance of broaden knowledge about the adaptive mechanisms of the myenteric plexus in different doing postnatal development, particularly in the transition phase of feeding behavior. It is known that there are changes in the dynamics of different neuronal types (for the neurochemical code) of the myenteric rumen plexus (with a predominance of inhibitory neurons in adult animals), according to this drastic change of eating behavior during the postnatal development, as well as the type of food. However, there is no consensus on the quantitative adaptations that occur with neurons of the myenteric plexus if they decrease in size and number of neurons in myenteric ganglion or remains stable during the postnatal development. (AU)