Comparative evaluation of methods for studying the degree of assimilation of feed by animals

Abstract

Relevance. The activity of the digestive organs is largely determined by the feeding regime, in particular, the frequency, timeliness, and the order of feeding the feed. The digestibility of nutrients is influenced by the preparation of feed for feeding, which facilitates mechanical processing in the digestive tract and the action of digestive enzymes. Against the background of a decrease in the natural resistance of the animal body, an important aspect is the use of mineral supplements and the enrichment of diets with biologically active substances that increase the nutritional value and the degree of assimilation of feed by animals. The aim of the work was a comparative assessment of methods for studying the degree of assimilation of feed by animals.Methods. To determine the degree of food assimilation, 2 drops of isotonic (0.9%) sodium chloride solution and a small amount of intestinal contents were applied to a glass slide, a thin smear was prepared, dried in air for 30 min, and large particles were removed. The preparations were fixed for 15 min with 96% ethyl alcohol, then 3–5 drops of a 1.0% aqueous solution of methylene blue, Lugol, Sudan III were applied. Along with the indicated conventional methods, we tested a method for preparing preparations using fixation in vapors of a 25.0% solution of glutaraldehyde for 30–40 minutes, in vapors of a 1.0% aqueous solution of osmium tetroxide.Results. The kinetics of the formation of intestinal microbiocenoses is characterized by a decrease in the number of lactobacilli and an increase in the number of pathogenic and opportunistic bacteria. In a comparative assessment of the preparation methods, the advantage of microscopic research methods is the possibility of a detailed study of the contents, the degree of assimilation of feed components in the gastrointestinal tract, and a visual assessment of the state of the intestinal microflora. The advantage of the method for preparing preparations with the use of vapor fixation of a 25.0% solution of glutaraldehyde and osmium tetroxide is the possibility of visualizing the formation of monospecific and polyspecies biofilms by optical and scanning electron microscopy. The preparations were sufficiently contrasting, there were no artifacts, bacteria and fungi stained brown, which made it possible to count even pinpoint colonies using a magnifying glass or an optical microscope. The easily digestible feed results in a low fecal yield and a stable consistency. The use of functional food “Pristine Gold Vet” in the nutrition of dogs and fur-bearing animals made it possible to increase the absorption of nutrients by 18,1% and 15,3%.