Impact of Autonomic Tonus Typological Features on the Duodenum Structure of Chickens

Abstract

The goal of this research is to show the relationship between the duodenum morphology of
laying hens (Gallus domesticus) of ISA Brown cross and typological peculiarities of autonomic
tonus in the poultry organism. To achieve the goal a group of adult chickens (aged one year)
was investigated to determine an aggregate tonus of their autonomic centers based on the study
of heart rate variability (variation pulsometry). According to the results all the poultry was
divided into two groups: sympatheticotonic chickens (hereinafter referred to as ST chickens)
and sympathetico-normotonic chickens (hereinafter referred to as ST-NT chickens) The first
group of poultry is characterized by a clear predominance of sympathetic centers tonus while
within the second group there is a slightly increased tonus of parasympathetic centers. Using
a set of various morphological methods a comparative analysis of the duodenum structure in
these groups was made. The analysis revealed that ST chickens unlike ST-NT chickens are
characterized by a higher value of the duodenum absolute length (by 1.6 cm) and its relative
length (by 1.4 %) as well as lower values of its internal perimeter (by 0, 25 cm). Apart from
this, an increase of absorption surface of the duodenum mucous membrane is observed in STNT chickens. Increase in villus height (by 143.7 micrometers) and their quantity (by 61.5) per
1sm2 contribute greatly to it. In the duodenum muscle membrane the thickness of both layers
has larger values under a distinct sympathetic tonus in ST-NT chickens. In a circular layer
difference between poultry groups reaches 21 micrometers while in a longitudinal it approaches
4.9 micrometers. Investigating a connective tissue it was found that the relative area of its fibers
near the mucosal crypts of ST chickens is larger by 0.21 % than that of the ST-NT chicken. In
the muscle layer area a superiority of ST chickens according to this indicator reduces to 0.15%.