Probiotic feed additive “EnzActive” against the background of hay-type fattening of young bulls

Standardized feeding of young cattle should be based on scientifically based standards, guaranteeing their genetic productivity potential, rational use of fodder resources, and proper feed payment with meat products. The current situation regarding the rationing of livestock feeding in global and domestic, both scientific and industrial practices, has fundamentally changed, which requires a significant revision of the traditional provisions on the organization of standardized feeding and feeding of farm animals. At the same time, the conceptual requirements for the organization of standardized feeding of young livestock should be based on the generalization of world experience in need of animals for energy, nutrients, and biologically active substances, taking into account the age period of fattening with an emphasis on the quality and biosafety of products. In the conditions of intensive production of meat products, to ensure high productivity, it is impossible to do without using feed products of natural substance, which should include additives with a purely biological effect. One of these includes the feed additive “En-zActive”, which contains a unique formula of a combination of biotic and enzymatic action, which consists of live yeast of the genus Saccharomyces cer evisiae, and a complex of six enzymes: protease, cellulose, xynalose, α - amylase, ß-gluconase and phytase. The research was based on optimizing the standardized feeding of fattening young animals on hay-type rations using the probiotic feed additive “EnzActive” based on 8 g/head per day. The research was conducted on Simmental bulls in the conditions of the “Pchany-Denkovych” farm of the Stryi district of the Lviv region. It was established that the use of the probiotic supplement “EnzActive” against the background of hay-type feeding contributed to the improvement of the intensity of the vital activity of the physiologically helpful microflora of the rumen, which had a stimulating effect in the processes of additional assimilation of nutrients. A positive result was obtained regarding the level of average daily growth and functional features of rumen microflora, the final period of fattening. Thus, based on the results of our research, it is possible to recommend introducing the hay type with the inclusion of probiotic feed additive “EnzActive” at the rate of 8 g/head into the intensive livestock technology fattening a day. No adverse side effects of “EnzActive” bio-additives on the general functional condition of young bull's residents were found.


Introduction
Intensive management of the meat sector of animal husbandry places increased demands on the quality of bulk feed (hay, silage, silage), which can occupy up to 70 % of the diet's nutrition in the same rations type of animal feeding (Gutyj et al., 2017;Bomko et al., 2018;Pivtorak & Mil, 2022).The effectiveness of feeding animals and predicting their productivity largely depends on the objective assessment of these feeds.In some cases, the existing standards do not always consider the physiological need of animals for nutrients and biologically active substances and therefore do not reflect the productive effect of bulk feed on the level of meat productivity.In the practice of procurement, bulk fodder of different classes and quality often do not differ in the efficiency of their feeding to animals, and therefore: with the increase in meat production, the requirements for the quality of bulk fodder increase (Borshch et al., 2020;Slivinska et al., 2020;Bashchenko et al., 2021;Mylostyvyi et al., 2021;Radchikov et al., 2021).
Aim of the research.After analyzing some alreadyknown scientific reports on the use of various quality bulk feeds in the diets of fattening bulls, the basis of our research was the intensive technology of fattening bulls on diets of different nutritional levels due to the use of bulk fodder of hay type with inclusion in the structure of a concentrated mixture about the biotic feed additive "EnzActive" produced by Ltd. "Enzym" company.
The probiotic feed supplement contains a unique formula of a combination of biotic and enzymatic action, which consists of live yeast of the genus Saccharomyces cerevisiae and a complex of six enzymes: protease, cellulose, xynalase, α-amylase, ß-gluconase, and phytase, which are encapsulated by a layer of inactive yeast cells.

Materials and methods
To solve the problem, we conducted a scientific and economic experiment in the conditions of the farm "Pchany -Denkovych", Stryi district, Lviv region, on Simmental breed goats.Three groups of ten heads each were selected.
The research used pre-made oat-barley-vaca-pea hay of different technological preparation when mowing the mixture mentioned above.The technological process consisted of the following: mowing in the phase of the emergence of cereals into the tube (haylage of category A), earing and flowering of haylage of category B), and earing of cereals and formation of pods (haylage of category C).The scheme of research is shown in Table 1.The duration of the experiment is 120 days.The rations of the experimental animals were balanced in terms of the content of exchangeable energy (MJ) and nutrients, taking into account dry Matter, digestible protein, sugar, starch, the ratio of calcium to phosphorus, provision of essential microelements due to the salt-micromineral premix, namely: Fe, Zn, Co, J, carotene.
During the experiment, the following indicators were studied and analyzed; chemical composition and nutritional value of hay, completeness of eating, and dynamics of live weight according to average daily growth.
After fattening was completed, three heads of typical animals were selected from each group to determine the course of metabolic processes in the body according to the average indicators of the rumen content.In the following one, a controlled slaughter was carried out to determine the preslaughter live weight, carcass weight, internal fat mass, slaughter yield, and by average samples after carcass deboning, determination of chemical composition, and evaluation of meat product indicators.

Results and discussion
The main task of the conducted research was to determine the comparative assessment of the nutritional value of hays of different categories in the diets of fattening cattle.
Based on the analysis of the obtained results, make recommendations to the farm as to which hay is the most nutritious and meets the standard requirements for its quality.
The rations of the experimental animals were balanced in terms of the content of exchangeable energy (MJ) and nutrients, taking into account dry Matter, digestible protein, sugar, starch, the ratio of calcium to phosphorus, provision of essential microelements due to the salt-micromineral premix, namely: Fe, Zn, Co, J, carotene.
During the experiment, the following indicators were studied and analyzed; chemical composition and nutritional value of hay, completeness of eating, and dynamics of live weight according to average daily growth.
After fattening was completed, three heads of typical animals were selected from each group to determine the course of metabolic processes in the body according to the average indicators of the rumen content.In the following one, a controlled slaughter was carried out to determine the preslaughter live weight, carcass weight, internal fat mass, and slaughter yield, and by average samples after carcass deboning, determination of chemical composition, and evaluation of meat product indicators.
The characteristics of the nutritional value of the manufactured hays are given in Table 2.The results were subjected to statistical processing using generally accepted methods of variational statistics with an estimate of the average arithmetic error and calculating the probability of differences according to the Student's method using MS Excel software.
The evaluation of the quality indicators of the manufactured hays showed that the parameters of the category B hay according to these indicators, such as the content of protein, as well as its fractions, fat, fiber, and soluble sugars, were the best and met the requirements of the first class of the existing standards.
Considering the requirements of the outlined tasks, the final result of the research was obtaining young beef in the most optimal terms of growing.After all, it is known that the demand for veal and young beef is exceptionally high.That is why one of the significant factors of livestock fattening with canned bulk fodder such as haylage is the efficiency of assimilation of nutrients in the diet.Thus, based on the task of the test animals' growth intensity, it is possible to confirm the positivity of its effectiveness.Indicators of increases in the live weight of experimental animals are given in (Table 3).The analysis of the obtained results showed that the fattening of bulls on the hay of different categories increased and was the highest in the third group, whose animals consumed hay of categories B the average daily gains in this group exceeded, respectively, the first and second groups by 22.4; 12.3 %.
The most important task of the conducted research was to assess the possibility of using the probiotic feed additive "EnzActive" in the structure of hay-type rations for fattening animals as a stimulator of the vital activity of symbiotic microorganisms of the ruminal environment.In this case, reports in literary sources regarding the mechanism of action of the above-mentioned biotic feed additive have not been found.Some publications report that most probiotics acti-vate the rate of enzymatic processes of the symbiotic microflora of the rumen (Mazur et al., 2020;Fedorovych et al., 2021;Pivtorak et al., 2022).
The development of the body of growing animals in the post-embryonic period includes growth, or the growth of live mass and various internal organs and tissues, which are most actively formed before the 12-month life cycle and largely depend on the consumption of dry Matter and energy (Desnoytr et al., 2009;Robinson & Erasmus, 2009;Klosova et al., 2019;Grymak et al., 2021;Pivtorak & Mil, 2022).
Taking into account these reports, we calculated the average consumption of dry Matter and available energy by growing bulls (Table 4).Analyzing the calculations, the specific influence of the type of rations on the consumption of dry Matter and energy in their growth and development was established.The maximum dry Matter and energy consumption per 100 kg live weight is typical for bulls.A gradual decrease up to 12 months of age causes an undesirable effect on the growth of muscle tissue.Thus, the efficiency of using dry Matter and exchangeable energy is influenced by age and diet type, consistent with reports.Therefore, this shortcoming should be compensated by the final intensive fattening due to the activation of microbial synthesis processes in the rumen of adult animals.
An essential indicator of the future high meat productivity of fattening cattle is the amount of feed consumed and the level of assimilation of nutrients and biologically active substances in the diet, estimated by digestibility in the gastrointestinal tract (Table 5).
Evaluating the obtained results of digestibility, it was found that all feeds were eaten willingly by the animals, and the residues were insignificant and insignificant.At the same time, it is possible to determine two aspects that influenced digestibility -age, and feeding.Comparing these indicators, it can be determined that the animals of the second and third groups, which consumed category B and B hay in the ration structure with the use of the probiotic feed additive "EnzActive" as part of the feed mixture, had better digestibility compared to the first group.This indicates the optimal balance of the rations and the stabilizing effect of bio supplements in the scar environment of the gastrointestinal tract.
The assessment of the intensity of metabolic processes in the body of fattening bulls was determined by the average indicators of the content of the rumen, which was obtained at the end of each month (Table 6).According to the analysis of the obtained results, a probable increase in the number of amylolytic and cellulolytic bacteria was revealed; the quantitative advantage (second and third group) compared to the first is 1.52-2.33 and 1.67-2.54million/ml, respectively.A similar picture is observed in the number of proteolytic bacteria; the difference is unlikely.
The most objective indicators that characterize the effectiveness of specific processes in the animal's body during the study of a particular factor of feed are the complex response to the vital activity of symbiotic microorganisms of the scar environment of the body of experimental cattle.In this case, we were interested in the effect of the studied feed additive on these processes.The increase in the basic bacterial biomass level in the rumen content of the second and third groups indicates a consistently positive effect of the probiotic feed additive.A characteristic feature of this process is a probable increase in the level of enzyme activity in general.In our case, the amylolytic, cellulolytic, and proteolytic activity levels increased.
Therefore, using the biotic feed additive "EnzActive" against the background of hay-type cattle fattening shows a positive effect.A scientifically justified dose is 8 g/head per day, or 800 g/t of compound feed, respectively.

Conclusions
The feeding of young Simmental breed in the structure of the diet of fodder mixtures from hay bales of category A, B, and B and the probiotic feed additive "EnzActive" did not harm the digestibility of nutrients, the intensity of growth and the metabolic processes of ruminal digestion.
Based on the results of our research, it is possible to recommend introducing a full-rational fodder mixture made from category B and B hays into the intensive livestock fattening technology.At the same time, use a lowconcentrate type of feeding; compound feed should consist of crushed corn grain -60 %; wheat -15 %; barley -5 %; oats -5 %; cakes -15 %, with the inclusion of the biotic feed additive "EnzActive" at the rate of 800 g/t compound feed.The introduction of this feed supplement into the structure of the rations of fattening bulls increases the vital activity of the physiologically helpful microflora of the rumen, which is a stimulating effect in the processes of additional assimilation of the nutrients of the ration by the body.

Table 1
Scheme of the final scientific and economic experiment of intensive fattening of bulls (n = 10)

Table 2
Nutritive value of hay

Table 3
Live weight and productivity of experimental bulls

Table 4
Average consumption of dry Matter and available energy of rations during intensive breeding of cattle (n = 10)

Table 5
Digestibility of nutrients in the diet by experimental bulls, % (n = 10)