Morphometric indicators of the wall of the crop of broiler chickens when using some biologically active feed additives
Authors: Cherepanova N. , Malorodov V. , Semak A. , Prosekova E. , Belyaeva N. 
Published: January 2023

Purpose: describe the histological structure and morphometric parameters of the crop of broiler chickens and determine the effect of the multienzyme preparation and humic substances on its structure.

Materials and methods. The multienzyme preparation contained beta-gluconase, pentosanase, proteolytic, lipolytic, cellulolytic and amylolytic enzymes. Group 1 received the main diet, balanced in all respects. Group 2 received an enzyme preparation 1 g/kg of feed in addition to the main ration. Group 3 received 1 g/kg of sodium humate feed in addition to the main diet. Group 4 received both an enzyme preparation and sodium humate, 1 g/kg of compound feed, in addition to the main diet. Withdrawal from the experiment occurred at 28 and 49 days of age. For research, 5 samples of crop from the group were selected.

Results. Studies have shown ongoing processes of growth and differentiation of structures within 49 days of cultivation. The thickness of the crop wall in birds of the control group decreases by 11.8 %, which may be due to an increase in the size of the organ, its fullness and the mechanical effect of the feed components on its wall. The decrease in the thickness of the wall of the crop by 49 days of age occurs mainly due to a decrease in the thickness of the muscular membrane by 38.5 %. The relative mucosal height increases with bird age from 44 % at 4 weeks of age to 53 % at 49 days of age. An increase in the height of the epithelium by 6.4 % is observed, and the thickness of the lamina propria decreases with age. By 49 days of age, in all experimental groups, the muscular coat is significantly larger, and the submucosa is smaller than in the control group. The maximum thickness of the muscular membrane in group 2 is 1.6 times more than in group 1. The relative height of the epithelium is minimal in groups 2 and 3 - 44 %. In these groups, a significantly greater wall thickness was observed than in the control group, mainly due to the muscular layer. Sodium humate does not adversely affect the structure of the crop. Long-term use of the multi-enzyme complex irritates the mucous membrane in the first period of cultivation. This is expressed in an increase in the thickness of the epithelium by 20%. Further, the wall adapts to the irritating effect of the drug, and in the second period of cultivation, no negative effect on the crop mucosa was found in this group. The complex use of additives in the first period of cultivation leads to inhibition of the development of all structures of the mucosa, except for the epithelium. Apparently, the negative effect of the enzyme preparation is affecting. But at the same time, the irritating effect of additives on the mucous membrane is not observed, since the height of the epithelium does not change significantly. Apparently, in this case, we see a positive adaptogenic effect of humic substances on the organ wall. In the second growing period, no negative effect of additives on the crop wall was found.

Conclusion. The wall thickness of the crop decreases with age, due to a decrease in the thickness of the muscular membrane. The height of the epithelium in the mucosa increases. Long-term use of sodium humate does not adversely affect the histological structure of the crop. The continuous use of enzyme preparations irritates the mucous membrane of the crop in the first period of cultivation, in the second period of such an effect of the additive is not observed. The combined use of these additives does not irritate the wall of the crop.