INTRODUCTIONFeed composition has a direct impact on thequalitative and quantitative characteristics of thegastrointestinal microbial community. Minerals andvitamins are essential micronutrients that participatein such vital processes as enzyme formation or thesynthesis and metabolism of hormones and vitamins.They affect the nervous, cardiovascular, and endocrinesystems, as well as the activity of the endocrine glandsand the gastrointestinal tract.311Giro T.M. et al. Foods and Raw Materials. 2022;10(2):310–317Micronutrient deficiency may trigger variousinfectious and non-infectious diseases [1, 2]. A poorlybalancedfeed ration often leads to undesirable changesin the microbiota of small ruminants. The resultingdigestive disorders cause various diseases andeventually lead to poor livestock yield. Biofortificationfortifies animal diet with essential nutrients, thusimproving the chemical composition of meat. It rendershigh-quality mutton that provides consumers withessential microelements [3–9].Practical microbiology gives scientific data onthe composition, role, or function of the microbialcommunity in the rumen content of small ruminants.However, some of these methods have disadvantagesor limitations. For instance, researchers cannot choosethe optimal environment for microbial cultivation.Fortunately, contemporary molecular genetic methodsmake it possible to skip the stage of cultivation andstudy microorganisms without the restrictions thattraditional diagnostic microbiology are prone to [10–14].Small intestine (lat. intestinum tenue) of farmanimals absorbs nutrients from the chyme. It is in thesmall intestine that the main digestion takes place,and this is where most digestive enzymes come from.Partially digested food leaves the stomach and entersthe duodenum, where it is processed by intestinal andpancreatic juices and bile. The small intestine is wheredigested food, toxins, poisons, medicinal substances,etc. are absorbed into the bloodstream or lymphaticchannel [15–19].The jejunum is somewhat structurally different fromother parts of the small intestine. Membrane digestionis at its utmost in the upper parts of the jejunum. As aresult, its wall is thicker; it has more folds in the mucousmembrane, denser villi, and a more abundant bloodsupply [20–22]. Therefore, the small intestine is a vitalsystem of animal body, and its flawless work is essentialfor sheep farming, which proves the relevance of thisresearch.Sheep farming needs new fundamental data onthe effect of biofortification on the bacterial rumencommunity. Bacterial profile includes normal, opportunistic,and pathogenic microflora, as well asnonculturable and transit microflora that does not affectthe life of the animal. Light microscopy revealed themorphology of the intestine and the main differencesbetween the samples obtained from animals fed withYoddar-Zn and DAFS-25.The research objective was to assess the effect ofessential microelements on the ruminal microbiocenosisand the microstructure of the jejunum in young rams.STUDY OBJECTS AND METHODSThe next-generation sequencing (NGS) revealedthe digestive microflora of seven-month-old rams ofthe Edilbaev breed. The experiment made it possibleto evaluate the effect of the feed additives Yoddar-Zn(Material Specifications TU 10.91.10-252-10514645-2019) and DAFS-25 (Material Specifications TU 10.91.10-253-10514645-2019). The studies took place in thelaboratory of molecular genetic research of the Researchand Production Company BIOTROF (St. Petersburg,Russia).The feed additives were developed at the VolgaRegion Research Institute for the Production andProcessing of Meat and Dairy Products. Both feedadditives contain Coretron, an enterosorbent usedin Russia in cattle diet, and cold-pressed pumpkincake, which served as a protein-carbohydratecomponent (Tables 1 and 2) [6].A scientific and economic experiment was necessaryto assess the effectiveness of various diets fortified withorganic microelements, i.e., mono- and di-iodotyrosinesand selenomethionine. After weaning from mothersat the age of four months, 100 lambs of the Edilbaevbreed were divided into four groups, 25 animals in each.The lambs were fed and fattened in the same way. Onday 105, when the animals were seven months old, theywere slaughtered by the traditional method according tothe Technical Regulations of the Customs Union on thesafety of meat and meat products TR TS 034/2013. Priorto slaughter, all experimental animals had received nofood for 24 hours.Yoddar-Zn is a source of bioavailable organiciodine and zinc. It also contains iodized milk proteinsassociated with amino acids and zinc compounds.Yoddar-Zn owes its biological properties to bound iodine,which is necessary for the biosynthesis of such thyroidhormones as thyrotoxin and triiodothyropine. They areimportant for metabolism and immune system [6].The control group of young rams received 300 gramsof mixed fodder per head per day. The first experimentalgroup received daily the same mixed fodder togetherTable 2 DAFS-25 feed additiveIngredient AmountPlant silicon(diotomite Coretron), %1.0Pumpkin cakeprotein-carbohydrate complex, %99.0,including 20.0of pumpkin cakeOrganic selenium(selenomethionine), mg /100g0.16Table 1 Yoddar-Zn feed additiveIngredient AmountPlant silicon(diotomite Coretron)1.0Iodine-containingadditive Yoddar-Zn, %1.0Pumpkin cakeprotein-carbohydrate complex, %98.0,including 20.0of pumpkin cakeOrganic iodine(mono- and di-iodotyrosines), mg/100g3.0312Giro T.M. et al. Foods and Raw Materials. 2022;10(2):310–317with 300 mg of Yoddar-Zn, the second experimentalgroup – 0.5 mg of DAFS-25, and the third experimentalgroup – a mix of these additives (300 and 0.5 mg).The effect of the organic additives was studiedin vivo by comparing the microbiocenosis and microstructuralparameters of the small intestine in theexperimental and control groups of young rams.The next generation sequencing (NGS) is currentlyone of the most optimal research methods. NGStechnologies provide metagenomic studies of complexmicrobial communities with a large volume of readnucleotide sequences. This technology is much moreaccurate than the Sanger sequencing in determining thephylogenetic species of microorganisms [23].The in vivo assessment of the impact on the intestinalmicrobiocenosis took 105 days. Samples of the rumencontents were put into sterile containers (Pan Eco,Russia) immediately after the slaughter and tested formicrobial composition. Next step included histology ofjejunum samples. The preparations were stained withhematoxylin and eosin to assess any possible changes inthe intestinal mucosa.The bacterial content of the ram rumen wasanalyzed by NGS method. Total DNA was isolated byusing the Genomic DNA Purification Kit (Fermentas,Inc., Lithuania) according to the manual. The finalconcentration of total DNA in the solution wasmeasured using a Qubit fluorimeter (Invitrogen, Inc.,USA) with Qubit dsDNA BR Assay Kits (Invitrogen,Inc., USA) according to the manual.The NGS was performed on a second-generationMiSeq sequencing platform (Illumina, Inc., USA) withprimers for the V3-V4 region of 16S rRNA; upstreamprimer – 5´-TCGTCGGCAGCGTCAGATGTGTATAAGAGACAGCCTACGGGNGGCWGCAG-3´; downstreamprimer – 5´-GTCTCGTGGGCTCGGAGATGTGTATAAGAGACAGGACTA-CHVGGGTATCTAATCC-3´ [24].Libraries were prepared with Nextera® XT IndexKitreagents (Illumina, Inc., USA); the PCR products werepurified with Agencourt AMPure XP (Illumina Inc.,USA); the sequencing was performed with MiSeq®ReagentKit v2 (500 cycle) (Illumina, Inc., USA) [25].The obtained reads underwent overlapping, filteringby Q30 quality, and primer trimming. The processinginvolved the Illumina bioinformatics platform (Illumina,Inc., USA). The quality control and assessment of thetaxonomic composition were carried out using theQIIME2 v.2019.10 software (https://docs.qiime2.org)and the Green-Genes database 13.5 (https://greengenes.secondgenome.com).Pieces of ram jejunum samples were removed bypreparation and fixed in 10% aqueous neutral formalinsolution at room temperature for 48 h. The selectedsamples were removed from the fixing liquid andwashed under running water for 48 h. For dehydration,the material was washed in alcohols of increasingconcentration from 50 to 96%. After that, the materialwas embedded in paraffin shaped in paraffin blocks.Sections of 5–8 μm were sliced with a sledge microtome,deparaffinized, and stained by Ehrlich hematoxylinand eosin dyes. Hematoxylin stains basophilic cellularelements bright blue, while eosin alcohol acid dye stainsY-eosinophilic cell elements pink. Basophilic structuresmost often contain nucleic acids (DNA and RNA), i.e.,nucleus, ribosomes, and RNA-containing cytoplasmsections. Eosinophilic elements contain intra- andextracellular proteins. Cytoplasm belongs to the maineosinophilic environment, so its elements stain brightred [1].Microscopy involved a Levenhuk MED PRO 600Fluo microscope, which is designed for transmitted lightbrightfield microscopy or for a luminescent (fluorescent)method (Magnification ×300).The morphometric analysis of the obtained datatraced the thickness of the jejunum layers. Theexperiment relied on a screw eyepiece micrometerMOV-1-15× and an eyepiece ruler with 60 units of scaledivision. The quantitative parameters of the histologicalstructures underwent further statistical processing.Statistical processing of the obtained digitaldata followed standard methods using the MicrosoftExcel 2010 (Microsoft Corp., USA) and the statisticaldata analysis package StatPlus 2009 Professional 5.8.4for Windows (StatSoft, Inc., USA). Student’s t-test wasapplied to assess the reliability of data between theexperimental and control groups.RESULTS AND DISCUSSIONThis section describes the effect of feed additivesYoddar-Zn and DAFS-25 in the diet of young Edilbaevbreed rams on their ruminal microbiocenosis andjejunum microstructure.The NGS analysis revealed the ruminal bacteriacommunity in the control and experimental groups.The rumen samples contained 31 phyla of bacteriaand 1 phylum of archaea (Fig. 1). Firmicutes andBacteroides predominated with a total share of 86–94%.The share of Actinobacteria, Spirochaetes, andCandidatus Saccharibacteria was 1–6%. In the controlgroup, Firmicutes ranked first: their relative valuein the community was 65%, while the proportion ofBacteroides was only 29.4%. This ratio was differentin the experimental groups. In the group that receivedYoddar-Zn, the proportion of Firmicutes and Bacteroideswas the same (42–43%). In the groups that receivedDAFS-25 and DAFS-25 + Yoddar-Zn, the ratio of thesetwo phyla was reversed compared to the control group:Bacteroides – 50–60%, Firmicutes – 30–35%.At the level of orders, the community was dominatedby Bacteroidales, Erysipelotrichales, and Clostridiales.Rams fed with DAFS-25 had a larger proportion ofBifidobacteriales (5.8%). The control group had moreErysipelotrichales – 28.8%.Cellulolytic bacteria are important bacterialcommunity members. They break down thefiber of plant foods and convert it to volatile fattyacids. Cellulolytic bacteria in the rumen sampleswere mainly represented by the bacterial families313Giro T.M. et al. Foods and Raw Materials. 2022;10(2):310–317Clostridiaceae, Prevotellaceae, Flavobacteriaceae,Eubacteriaceae, Lachnospiraceae, Ruminococcaceae,and Thermoanaerobacteraceae, as well as by theBacteroidetes phylum.The total proportion of cellulolytic bacteria wasdifferent in all samples. The share of beneficialcellulolytic bacteria ranged from 51.3 to 75.4%,depending on the sample. The control group had thesmallest proportion of cellulolytic bacteria, while thegroup that received DAFS-25 had the largest one. In thegroups treated with Yoddar-Zn and DAFS-25 + Yoddar-Zn, the proportion of cellulolytic bacteria was 56.6 and64.1%, respectively.Lactate-utilizing bacteria are another importantgroup in the ruminal bacterial community. They fermentlactic acid produced by bacteroids and lactic acidbacteria and other organic acids into volatile fatty acidsused in metabolic processes.The NGS analysis showed that the content ofVeillonellaceae lactate-utilizing bacteria was very largein some samples. In the groups that received Yoddar-Zn and DAFS-25 + Yoddar-Zn, their content was 20.6and 12.9%, respectively, while the control group and theexperimental group fed with DAFS-25 alone, it was 9.1and 5.1%, respectively. This indicator may demonstratethat these bacteria are especially active in the sheeprumen, depending on their physiological state of theanimal.The share of bacterial pathogens was insignificantin all samples and totaled about 0.5% in all groups.Opportunistic Enterobacteriaceae were also representedin a very small amount (≤ 0.1%) in all samples.Prevotella appeared to be the dominant genus.Its relative abundance in the experimental groupsexceeded the control (28.3, 38.9, and 33.4% vs. 22.8%).Prevotella sp. often is the most numerous genera inFigure 2 Rumen microbial community at the level of orders, %0102030405060708090100Firmicutes Bacteroidetes ПрочиеActinobacteria Proteobacteria SpirochaetesEuryarchaeota Acidobacteria Candidatus_SaccharibacteriaChloroflexi Fibrobacteres PlanctomycetesVerrucomicrobia0102030405060708090100Control Yoddar-Zn DAFS-25 Yoddar-Zn + DAFS -25Firmicutes BacteroidetesActinobacteria ProteobacteriaEuryarchaeota AcidobacteriaChloroflexi FibrobacteresOthersSpirochaetesCandidatus_SaccharibacteriaPlanctomycetesVerrucomicrobia0102030405060708090100Control Yoddar-Zn DAFS-25 Yoddar-Zn + DAFS -25Firmicutes BacteroidetesActinobacteria ProteobacteriaEuryarchaeota AcidobacteriaChloroflexi FibrobacteresOthersSpirochaetesCandidatus_SaccharibacteriaVerrucomicrobia0102030405060708090100Control Yoddar-Zn DAFS-25 Yoddar-Zn + DAFS -25Firmicutes BacteroidetesActinobacteria ProteobacteriaEuryarchaeota AcidobacteriaChloroflexi FibrobacteresOthersSpirochaetesCandidatus_SaccharibacteriaPlanctomycetesVerrucomicrobia0102030405060708090100Control Yoddar-Zn DAFS-25 Yoddar-Zn + DAFS -25Firmicutes BacteroidetesActinobacteria ProteobacteriaEuryarchaeota AcidobacteriaChloroflexi FibrobacteresOthersSpirochaetesCandidatus_SaccharibacteriaPlanctomycetesVerrucomicrobia0102030405060708090100Control Yoddar-Zn DAFS-25 Yoddar-Zn + DAFS -25Firmicutes BacteroidetesActinobacteria ProteobacteriaEuryarchaeota AcidobacteriaChloroflexi FibrobacteresOthersSpirochaetesCandidatus_SaccharibacteriaPlanctomycetesVerrucomicrobia0102030405060708090100Control Yoddar-Zn DAFS-25 Yoddar-Zn + DAFS -25Firmicutes BacteroidetesActinobacteria ProteobacteriaEuryarchaeota AcidobacteriaChloroflexi FibrobacteresOthersSpirochaetesCandidatus_SaccharibacteriaPlanctomycetesVerrucomicrobia0102030405060708090100Control Yoddar-Zn DAFS-25 Yoddar-Zn + DAFS -25Firmicutes BacteroidetesActinobacteria ProteobacteriaEuryarchaeota AcidobacteriaChloroflexi FibrobacteresOthersSpirochaetesCandidatus_SaccharibacteriaPlanctomycetesVerrucomicrobiaFigure 1 Rumen microbial community at phylum level, %0102030405060708090100Bacteroidales Erysipelotrichales SelenomonadalesCoriobacteriales Bifidobacteriales MethanobacterialesLactobacillales Pseudomonadales EnterobacterialesBacillales FlavobacterialesClostridialesSpirochaetalesSphingobacterialesOthers0102030405060708090100Control Yoddar-Zn DAFS-25 Yoddar-Zn + DAFS -25Firmicutes BacteroidetesActinobacteria ProteobacteriaEuryarchaeota AcidobacteriaChloroflexi FibrobacteresOthersSpirochaetesCandidatus_SaccharibacteriaPlanctomycetesVerrucomicrobia010203040506070Control Yoddar-Zn DAFS-25 Yoddar-Zn + DAFS -25Firmicutes BacteroidetesActinobacteria ProteobacteriaEuryarchaeota AcidobacteriaChloroflexi FibrobacteresOthersSpirochaetesCandidatus_SaccharibacteriaPlanctomycetesVerrucomicrobia0102030405060708090100Control Yoddar-Zn DAFS-25 Yoddar-Zn + DAFS -25Firmicutes BacteroidetesActinobacteria ProteobacteriaEuryarchaeota AcidobacteriaChloroflexi FibrobacteresOthersSpirochaetesCandidatus_SaccharibacteriaPlanctomycetesVerrucomicrobia0102030405060708090100Control Yoddar-Zn DAFS-25 Yoddar-Zn + DAFS -25Firmicutes BacteroidetesActinobacteria ProteobacteriaEuryarchaeota AcidobacteriaChloroflexi FibrobacteresOthersSpirochaetesCandidatus_SaccharibacteriaPlanctomycetesVerrucomicrobia0102030405060708090100Bacteroidales Erysipelotrichales SelenomonadalesCoriobacteriales Bifidobacteriales MethanobacterialesLactobacillales Pseudomonadales EnterobacterialesBacillales FlavobacterialesClostridialesSpirochaetalesSphingobacterialesOthers0102030405060708090100Bacteroidales Erysipelotrichales SelenomonadalesCoriobacteriales Bifidobacteriales MethanobacterialesLactobacillales Pseudomonadales EnterobacterialesBacillales FlavobacterialesClostridialesSpirochaetalesSphingobacterialesOthers8090100Bacteroidales Erysipelotrichales SelenomonadalesCoriobacteriales Bifidobacteriales MethanobacterialesLactobacillales Pseudomonadales EnterobacterialesBacillales FlavobacterialesClostridialesSpirochaetalesSphingobacterialesOthers0102030405060708090100Bacteroidales Erysipelotrichales SelenomonadalesCoriobacteriales Bifidobacteriales MethanobacterialesLactobacillales Pseudomonadales EnterobacterialesBacillales FlavobacterialesClostridialesSpirochaetalesSphingobacterialesOthers314Giro T.M. et al. Foods and Raw Materials. 2022;10(2):310–317sheep rumen. For instance, Prevotella also dominated ina similar study by Cui et al. on the effect of seleniumfeed additives on the microbial community in sheep [3].Cui et al. also proved the significant effect of seleniumon ruminal bacterial populations and microbialfermentation in the rumen in general.Subdominant microorganisms in the rumen wererepresented by the Dysgonomonas, Saccharofermentans,Tangfeifania, and Treponema genera. Cui et al. showedthat the abundance of Saccharofermentans sp. was ininverse relationship with selenium. Our research, on thecontrary, proved that the amount of Dysgonomonas sp.and Prevotella sp. depended on the presence of seleniumin the diet.To identify and evaluate the changes in the smallintestine wall, jejunum wall pieces were subjected tomicroscopy [1].This research of the effect of biofortification onthe microstructure of sheep jejunum yielded a moreaccurate assessment of the safety of Yoddar-Zn andDAFS-25 for small rumens [7, 8].Light microscopy of the jejunum in all samplesrevealed that the mucous membrane was well-structured,with distinct layers. The mucous membrane of thejejunum consisted of four layers: innermost mucosaoutermost, submucosa, muscularis (outer and innerlayers), and serosa. The columnar villi (Fig. 3) of themucosal epithelial layer were distinct and consisted ofa single-layer columnar epithelium lining the crypts.The structure of the layer was dominated by gobletcells and limbic epithelial cells, which produce mucus.The lamina propria consisted mostly of cells and fibersof loose fibrous connective tissue. The muscular layerwas represented by two distinct alternating layers ofmyocytes: annular and longitudinal. The submucosa wasrepresented by loose fibrous tissue with clear contouredblood and lymphatic vessels, as well as complex tubularalveolarglands that produced intestinal juice.The muscular membrane of the jejunum tissue hadtwo distinct layers of myocytes, which were separatedby a minimal layer of connective tissue. The structurewas clear; the cells were elongated and spindle-shaped.On the outside, the jejunum was covered with aserous membrane with layers of loose connective tissueand mesothelium. The integrity of the latter was intact.Figure 3 shows the mucous membrane of the jejunumsamples in the control group. The general histologicalstructure remained the same. We observed a slightaccumulation of mucus between the villi producedby goblet cells. Epithelial cells were of an elongatedcylindrical shape. The glands of the lamina propria werewell expressed. The integrity of the layers was intact.The jejunum samples in the experimental groups hadsome histological features that differed from the controlgroup samples.The jejunum of young rams that received Yoddar-Znhad a single-layer cylindrical border epithelium on thetransverse sections of the villi (Fig. 4).The lumen of the tubular glands looked deserted,and the crypts were separated by a minimal layer ofFigure 3 Jejunum samples in control group. Epitheliocytes ofcylindrical villi and gland; stained with Ehrlich hematoxylinand eosin. Magnification ×300Figure 4 Jejunum samples in group fed with Yoddar-Zn.Goblet cells of the villi are quite pronounced; stainedwith Ehrlich hematoxylin and eosin. Magnification ×300Figure 5 Jejunum sampled in animals fed with DAFS-25.Epitheliocytes are cylindrical, the villi are distinct andelongated; stained with Ehrlich hematoxylin and eosin.Magnification ×300Figure 6 Jejunum samples in animals fed withDAFS-25 + Yoddar-Zn. The villi are distinct, with cylindricalgoblet cells; stained with Ehrlich hematoxylin and eosin.Magnification ×300315Giro T.M. et al. Foods and Raw Materials. 2022;10(2):310–317connective tissue (Fig. 4). The muscular plate of themucosa was well expressed; the submucosa consisted ofconnective tissue layers with elongated tubular glands.The integrity of all membranes was intact.Figure 5 shows the jejunum samples obtainedfrom animals that received DAFS-25. The cylindricalepitheliocytes and the villi of the lamina propria weredistinct, with moderately pronounced glands with emptylumens and numerous goblet cells. The integrity of themembranes was intact: the muscle layers were separatedfrom each other by connective tissue. The serous tissuewas hardly developed.Figure 6 shows the jejunum samples obtained fromanimals that received DAFS-25+Yoddar-Zn. The organwall had a very obvious microstructure. The structure ofthe mucous membrane of the small intestine was intact,its constituent elements having clear contours. Thegoblet cells and the single-layered columnar epitheliumwere quite distinct. The villi were separated from eachother by a minimal layer of connective tissue. Thesubmucosa demonstrated contoured blood vessels, someof which were filled with blood. This fact indicates amore intensive metabolism in animals fed with DAFS-25+Yoddar-Zn.The myocytes of the muscular membrane are quiteclearly separated by loose fibrous connective tissuewith a minimal number of blood vessels. Musclecells corresponded to the state of contraction, i.e., thecells were as if the muscle was contracted, and themorphology of the early autolysis process.The morphological analysis proved that the structureof the jejunum wall in the control and experimentalgroups was intact and typical. The layers had an integralstructure in all experimental groups. Samples obtainedfrom animals that received DAFS-25 + Yoddar-Znhad the best developed structure.Table 3 shows that the arithmetic mean valueof the thickness of the jejunum mucous layer was19.40 ± 0.55 μm in the rams of the experimental groups,which exceeded the control by 2.0 μm. The thicknessof the muscular membrane in experimental groupsalso exceeded this indicator in the control group by anaverage of 0.8–2.0 μm. The experimental rams also hada slightly thicker serous layer.The minimal thickening of the jejunum membraneswas minimal in the experimental groups,the lowest observed in the animals that receivedDAFS-25 + Yoddar-Zn. This fact may be an indirectindicator of a more active digestion, a better digestibility,and a greater absorption of feeds and nutrients intothe bloodstream.CONCLUSIONBiofortification of young rams’ diet with essentialmicroelements had a positive effect on the quality andquantity of the gastrointestinal microbial community,which means a better digestion process and a greateranimal yield.In the rumen samples, cellulosolytic bacteria,which break down the fiber of plant foods into volatilefatty acids, were mainly represented by Clostridiaceae,Prevotellaceae, Flavobacteriaceae, Eubacteriaceae,Lachnospiraceae, Ruminococcaceae, and Thermoanaerobacteraceaefamilies, as well as by the Bacteroidetesphylum. The content of lactate-utilizing bacteria in therumen samples reached 40%, which may indicate a highdegree of activity of these bacteria, depending on theirphysiological state of the animal.The content of bacilli in the rumen sampleswas ≤ 1%. The total proportion of pathogenic speciesranged from 0.2 to 6.3%. The experiment revealed ≥ 50types of pathogenic microorganisms, which were mostabundant in the group fed with Yoddar-Zn + DAFS-25.The pathogenic microorganisms belonged to erysipelothrix,fusobacterial, and streptococci. Thecontent of porphyromonas reached 0.68% of totalmicroorganisms, while the proportion of Treponema inthe samples ranged from 0.6 to 1%. Lactobacilli wererepresented mainly by Lactobacilliales (0.06–0.45%).This fact may indicate a high degree of activity ofthese bacteria in the sheep rumen, depending on theirphysiological state of the animal.The balance of the microflora in the sheep rumensamples was good, and the amount of beneficialmicroflora was enough to inhibit the pathogenic andopportunistic bacteria.The light microscopy revealed no adverse effectof the feed additives DAFS-25 and Yoddar Zn on themicrostructural parameters of sheep jejunum. Therefore,they can be recommended for fattening purposes inindustrial conditions.The additives had no negative impact on the rumenmicrobiocenosis and the jejunum microstructure.The structure of the jejunum corresponded to themorphological characteristics for this type and age ofTable 3 Wall thickness of the jejunum of seven-month-old rams fed with various feed additivesResearch subject Wall thickness, μmMucus membrane Muscular membrane Serous membraneControl 17.40 ± 1.07 8.30 ± 0.79 0.80 ± 0.51Yoddar-Zn 19.10 ± 0.52 9.50 ± 0.81 0.90 ± 0.22DAFS-25 19.40 ± 0.97 9.60 ± 0.79 0.90 ± 0.55DAFS-25 + Yoddar-Zn 19.80 ± 0.97* 10.30 ± 0.71* 1.00 ± 0.44*P ≤ 0.005316Giro T.M. et al. Foods and Raw Materials. 2022;10(2):310–317farm animal in all the groups. A clearer micropicture ofthe jejunum wall was revealed in the experimental groupof rams fed with DAFS-25 + Yoddar Zn.The complex application of additives DAFS-25 andYoddar Zn helped optimize the processes of digestion,absorption, and assimilation of feed nutrients, whichwas partly confirmed by the minimal thickening of thejejunum membranes.Further research is needed to study the effect ofthese additives on other important systems of animalorganism, e.g., digestive (liver), excretory (kidneys),nervous (cortex and base of brain), and immune (spleenand mesenteric lymph nodes) systems.CONTRIBUTIONAuthors are equally relevant to the writing of themanuscript, and equally responsible for plagiarism.CONFLICT OF INTERESTThe authors declare no conflict of interest.