Levucell SB: live yeast – healthy digestion of broiler chickens

. This work is devoted to the use of probiotics in growing broiler chickens and the problem of obtaining poultry products of high biological properties, produced with the minimum use of antibiotic and chemical substances that can harm both the consumer and the environment. World practice shows the gradual rejection of feed antibiotics. The ban on the use of feed antibiotics does not lose its relevance in Russia. This is due to both the growth in demand for livestock products obtained without the use of antibiotics, and the tightening of veterinary and sanitary rules. Obtaining such products includes a set of measures, which includes the use of natural feed additives that optimize the functioning of the digestive tract and allow reducing or avoiding the use of antimicrobial agents. The role of intestinal microflora for maintaining the normal functioning of the intestine, performing a number of important physiological functions is presented, it is shown what parameters when growing broiler chickens affect the composition of the microflora of the digestive system, and what contributes to the spread of intestinal infections in poultry farms. The characteristics of the probiotic are given and the mechanism of action and biological properties of the additive are considered. Issues related to the feasibility of prophylactic and therapeutic use of probiotics in poultry farming, intended to restore and maintain beneficial microflora of the gastrointestinal tract, as well as to control pathogenic microflora, are considered.


Introduction
For many years, feed antibiotics have occupied a significant niche as additives in compound feed for poultry.Since 2006, when the EU countries abandoned their use due to the risk of the appearance of resistant strains of bacteria in food of animal origin, probiotics, prebiotics, synbiotics, phytobiotics, etc. have been used as replacements.All these drugs have one thing in commonthey all affect the microflora of the gastrointestinal tract [1,[3][4][5][6][7][8][9][10][11].Their distinctive feature is environmental safety, they do not have side effects, are utilized by the body of animals and do not harm either the health of the end consumer of the product or the environment [4,5,9].
In our country, the issue of food quality is especially relevant in connection with the deteriorating health status of the population, an increase in the number of people with food allergic reactions.The obvious dependence of human health on the quality of food products determines the urgency of the problem of obtaining products from farm animals and poultry that are free of antibiotics and other chemotherapy drugs.Over the past decade, a large body of evidence has accumulated on the potential dangers of antibiotic residues in meat and eggs.
In addition, the emergence of antibiotic-resistant strains of microflora can lead to changes in the composition of the microflora of the digestive tract and poultry diseases [4].
The spread of intestinal infections in poultry farms is facilitated by a difficult situation associated with an accumulated pathogenic background, economic instability leading to imbalance in feeding, with the appearance of toxic feed in the diet and an increase in their contamination with pathogenic and opportunistic microorganisms (including salmonella).The resulting disturbances in digestion processes cause significant economic damage, both from direct losses of livestock, and from a decrease in its productivity.
Currently, in the industrial poultry industry, gastrointestinal diseases of poultry rank second after viral infections and are the main cause of death of chickens in the early postnatal period, which is an urgent problem for the entire industry.
The practice of domestic and foreign studies shows that in the prevention of gastrointestinal diseases in young animals, new feeding schemes are increasingly used, aimed at limiting intestinal colonization by pathogens.In such cases, careful development of programs for the prevention and health of poultry with well-thought-out antibiotic therapy regimens in conjunction with probiotics is required.At the same time, probiotics regulate microbiocinosis in the gastrointestinal tract of birds, thereby improving health and productivity and safety [12].
Currently, in the industrial poultry, the prophylactic and therapeutic use of probiotics is widespread, which are one or more active live cultures of microorganisms designed to restore and maintain the beneficial microflora of the gastrointestinal tract, at the same time are safe for the health of consumers.

Parameters affecting the change in the gastrointestinal tract microflora
Highly productive crosses of birds are sensitive to stress, therefore, stricter adherence to the conditions of keeping and feeding is required.In addition, it is important that the feed is not only nutrient-balanced, but also free of pathogenic bacteria, mold and toxins.The pressure of pathogenic microflora entering the body with food and water of poor sanitary and hygienic quality, animals and birds constantly experience [9].
With intensive industrial cultivation of poultry, changes in the microflora in the intestinal tract more often occur as a result of various adverse effects: changes in diets, feed composition, violation of feeding regimes, stress (for example, during transplantation), the intake of pathogenic microorganisms with feed and water, the use of non-benign feed also, during and after antibiotic treatment, qualitative and quantitative changes in the normal intestinal microflora can occur [7,10].All this significantly affects the composition of the microflora of the digestive system and causes disorders of fermentation processes in the large intestine.

The role of intestinal microflora
It is simply impossible to create sterile conditions when raising animals, therefore it is necessary to strengthen the immune system and maintain a balance of beneficial microflora of the digestive tract [10].
The main functions performed by the intestinal microflora in the body: 1. Digestive function: with the help of bacteria, the breakdown of proteins, fats and carbohydrates occurs, creating conditions for the optimal course of digestion and absorption in the intestine; normalization of liver function.
2. Protective function: the synthesis of the substances necessary for the subsequent formation of various antibodies, which are the main mechanism for the protection of the body from foreign microorganisms and substances; suppressing the development of pathogenic microorganisms; detoxification of the body on substances negatively affecting the body (toxins, etc.); participation in reducing processes (antioxidant function), the formation of the acidity of the medium (by producing acetic, formic, amber and lactic acids) in various intestinal deposits (oppression of pathogens, assimilation of nutrients), and also bacteria help to maintain intestinal peristalistics and intestinal intestinal integrity.
3. Metabolic function: synthesis of vitamins of group in, enzymes, amino acids, synthesis of biologically active substances (volatile fatty acids, hormones, etc.); improving zinc absorption, calcium, iron, copper, phosphorus, manganese -micro-and macroelements, also vital for the body of birds [9].
The role of the intestinal microflora is important for maintaining the normal functioning of the intestine, performing a number of important physiological functions, such as ensuring the integrity and barrier function of the intestinal mucosa, suppressing the growth of pathogenic microorganisms and inducing immune response mechanisms at the level of the intestinal mucosa, absorption of vitamins and nutrients [8].Thus, the microflora of the gastrointestinal tract participates in many vital physiological processes and has not only local, but also a systematic influence.

Study of the effectiveness of the use of probiotic in feeding broiler chickens
Only a properly selected probiotic is able to quickly restore the normal intestinal microflora and protect it from the influence of adverse factors, thereby helping to realize the genetic potential of modern birds, improve the functioning of the immune system, and increase safety and productivity.
The aim of the research was: to study the effectiveness of using Levucell SB Titan Plus probiotic containing live yeast S in broiler chickens' diets.cerevisiae var.boulardii (I 1079) not less than 2 x 10 9 CFU/g, coated with stearic acid.
Yeast included in the composition of the Levucell SB Titan Plus, retain vitality during transit through the entire digestive tract, are not susceptible to high acidity in the stomach and bile salts, help restore the balance of microflora.The protective shell of the capsule prevents mechanical and thermal effects on live yeast culture Saccharomyces cerevisiae boulardii in the production of feed, in particular when pelleting.
The mechanism of influence on the composition of the intestinal microflora includes direct antagonism -S.boulardii reduces growth of Clostridium albicans, Escherichia coli, Salmonella typhi, Shigella dysenteriae, Vibrio cholerae, Salmonella enteritidis and Clostridium difficile.Also Levucell SB Titan Plus reduces the secretion of toxins by pathogenic bacteria and binds them, preventing toxins from having a destructive effect on the mucous membrane of the digestive tract.Stimulates enzymatic activity in the intestines, increasing the absorption of nutrients, helps to restore and strengthen the intestinal mucosa.
In addition, yeast secretes biologically active substances that help restore the walls of enterocytes and strengthen the intestinal mucosa.
Scientific and production experience was carried out on cross broilers «ROSS 308» from one day to 35 days of age in the Moscow State Academy of Veterinary Medicine and Biotechnology -MVA by K.I.Skryabin vivarium in 2021.

Materials and methods
The purpose of the experimental work was: study of the effectiveness of using a yeast probiotic preparation Levucell SB Titan Plus in broiler chicken diets to improve the digestive function and increase the productivity of poultry.The chickens were kept in cage batteries of the R-15 type, 30 heads in each group, in compliance with all technological parameters.
The birds were fed in three phases: start from 0-14 day, growth from 15-28 day and finish from 28-35 days.All laboratory tests were performed in the laboratory of the Federal Scientific Center "All-Russian Research and Technological Institute of Poultry" of the Russian Academy.

Results and discussion
The results of the experiment show the positive effect of probiotic on the productivity of broiler chickens.Application of the Levucell SB Titan Plus contributed to an increase in the live weight of broilers of 21 days of age by 5.1% in relation to the control group.The average live weight of 36-day-old chickens exceeded that of the control group by 2.8%.Average daily gain in live weight of poultry was quite high -60.1 g.In the test group, the consumption of feed per 1 kg of live weight gain was less than in the control, by 2.8%.
The results obtained were dependent on the digestibility and nutrient utilization of the broiler chicken feed (Table 2).
Inclusion of the Levucell SB Titan Plus in compound feed for broiler chickens contributed to an increase in the digestibility of dry matter of feed by 2.15%, proteinby 1.4%, fatby 1.5%, fiberby 2.8%.Chickens of this group used better feed nitrogen by 2.7%, lysineby 1.9%, methionineby 1.5%.There were no significant differences between the groups in the use of calcium and phosphorus.
Studies of the meat qualities of broilers (table 3) showed that in the experimental group there was a higher slaughter yield of gutted carcasses by 1.5 % and the release of the most valuable part of the carcasses -the pectoral muscles on 1.8%.The relative mass of the internal organs of broilers -muscle stomach, liver and heartboth in the control and experimental groups, was within the physiological norm (Table 4).The chemical composition of the pectoral muscles of broilers is presented in Table 5.There were no significant differences in all the studied parameters between the control and experimental groups.The content of vitamins in the liver of broiler chickens did not differ significantly between groups and corresponded to the physiological norm (Table 6).Table 7 shows the results of studies of the microflora of the large intestine of poultry and indicators characterizing its resistance.When studying the composition of microflora in the large intestine, there is a general positive dynamic in the ratio of lactic acid bacteria to pathogenic bacteria increased by 2.5 times.Using the yeast probiotic Levucell SB Titan Plus, even against the background of conventional feed for broilers, helps to restore the microbial balance in the digestive tract of poultry, create natural barriers to the penetration of unwanted microorganisms into the body of a bird and improve digestive function, which together is an important prerequisite for stimulating productivity and obtaining high-quality poultry products.

Conclusion
The results of the study allow us to make a conclusion about the positive impact of the Levucell SB Titan Plus on the productivity and health of broiler chickens.These results are obtained by improving the digestibility and use of nutrients in poultry feed, due to the normalization of intestinal microflora and healthy digestion.
Through its action the Levucell SB Titan Plus is able to quickly restore normal intestinal microflora and protect it from the influence of adverse factors.Live yeast Saccharomyces cerevisiae boulardii stimulate the enzymatic activity of the intestines, increasing the absorption of nutrients in feed.They also synthesize vitamins and convert trace elements into more accessible proteinate forms, contributing to a better supply of micronutrients to the body.In addition, yeast is not sensitive to antibiotics and can be used simultaneously with them, preventing dysbiosis, as well as for complex therapy and prevention of clostridiosis, colibacillosis, salmonellosis.

Table 3 .
Results of the control slaughter of chickens

Table 4 .
The mass of some internal organs of broilers

Table 5 .
The chemical composition of the pectoral muscles of broilers,%

Table 6 .
The content of vitamins in the liver of chickens, μg/g

Table 7 .
Indicators of the content of microorganisms in the intestines of broilers