INTRODUCTIONIn the world production of poultry, the share ofwaterfowl meat is 7.2%, specifically duck meat – 4.2%,goose meat – 3%. Their share in the gross productionof poultry meat tends to increase. In industrial poultryfarming, the problem of controlling bacterial infectionsof waterfowl is of genuine concern. Salmonella andCampylobacter are considered the most commonetiological zoonotic factors worldwide, with productivepoultry being the main source of infection.In recent years, there has been an increase in therelative number of infections caused by Salmonellaspp. and Campylobacter spp. The microorganisms arewidespread in most warm-blooded and farm animals,including poultry. Ducks’ infection with salmonella canbe detected at the age of about 14 days, and by the endof cultivation the whole flock can be found infected.Experimental studies showed that a small dose (less than40 CFU) of S. enteritidis is sufficient to fully colonizethe poultry intestines. This can lead to complete flock’s infection in 48 h [5–7]. Microorganisms can colonizethe intestinal tract of poultry in large quantities, often atabove 106–108 CFU/g of intestinal contents. The highestconcentrations of bacterial pathogens are known to bepresent in the intestinal mucosa [4].Poultry products can be contaminated at manystages of the “from farm to table” food chain, but thestrategic one is the stage of primary poultry production.Following biosafety guidelines of GMP/HACCPsignificantly reduces the colonization of poultry bybacterial pathogens and, later, the contamination ofcarcasses during processing. The European Food SafetyAgency’s monitoring (2008–2018) showed that about86% of poultry carcasses in Europe were contaminatedwith Campylobacter and Salmonella bacteria.In poultry production, main methods of infectioncontrol are taken at the stage of the cultivation in farms.Environmentally safe methods that ensure poultryquality and safety hold promise. Effective systemsof poultry cultivation, feeding, and maintenanceare reqired to control the spread of Salmonella andCampylobacter in poultry products. Bio-safetymeasures, decontamination of dropping and water arepotentilly productive. Antibacterial drugs in treatingof bacterial infections in poultry are considered a riskfactor contributing to the development of antibioticresistantstrains.Following the trend of avoiding antibiotics, thesearch for new control methods is becoming increasinglyimportant in poultry farming. The applicationof antimicrobial alternatives is highly potential.They include feed additives that are inhibitors ofbacterial pathogens, as well as probiotics, prebiotics,bacteriophages, bacteriocins, which in combinationprevent antibiotic-resistant strains of microorganismsand inhibit their proliferation [9–12].Consequently, natural alternative antibacterialpreparations are a way to reduce poultry gutcolonization by pathogenic microflora. This is themost acceptable natural alternative to salmonella andcampylobacter control that is economically viable anddoes not pose a risk to human health, animals, or theenvironment [3, 9]. Effective protection of poultryagainst pathogens, naturalness and safety, growthpromotion, and economic effectiveness are the criteriafor new alternatives to antibiotics [11, 13].One of the requirements for probiotics use is thecompetitiveness of antagonistic microflora found inthem. In order to prevent intestinal colonization bybacterial pathogens, probiotics are recommended for usefrom the first day of the birds’ life. Prebiotics promotethe development of birds’ own symbiotic microflora,which can inhibit pathogens and reduce their adhesion toenterocytes.Research suggests that some natural compoundshave biological activity against salmonella proliferation,but few have shown efficacy in experiments on animals.“Actigen” prebiotic (Alltech) is a concentrated purefraction of mannan oligosaccharides isolated from thecell walls of Saccharomyces cerevisiae yeast. The mainadvantage of these complex carbohydrates is their abilityto adsorb certain strains of bacteria that have type Ifimbriae (mannose-sensitive) and prevent intestinalcolonization by pathogens. Besides, the industrialexperiment proved the influence of combined use ofmannan oligosaccharides and probiotics on intestinalmicrobiocenosis and duck productivity [14, 15].We aimed to develop a method for preventingbacterial infections and increasing duck productivityusing probiotics and prebiotics. The method wasbased on the study of adsorbing capacity of mannanoligosaccharides (MOS) and antagonistic propertiesof Bifidobacterium spp. and Lactobacillus spp. againstSalmonella enteritidis and Campylobacter jejuni. Wealso aimed to analyze a combined effect of the cultureson gut microbiocenosis (activity and colonization) andon productivity of ducks.STUDY OBJECTS AND METHODSWe used Salmonella enteritidis and Campylobacterjejuni isolated from poultry carcasses of Ukrainianfarms. The studies were carried out in 2014–2018 atSumy National Agrarian University, Sumy. The poultrycarcasses were subjected to a detailed examinationfor pathomorphological changes. The liver, muscles,cloaca contents, ovaries, and various segments of theovoid were aseptically assembled to be screened forsalmonellosis and campylobacteriosis. Isolation andidentification of microorganisms was carried out usingtests recommended by “Bergey’s Manual” (1997) [35].At the first stage (in vitro), we studied the ability ofmannan oligosaccharides isolated from the cell wallsof Saccharomyces cerevisiae yeast to adsorb bacterialpathogens. In our experiments we used 27 strains ofSalmonella enteritidis and 13 strains of Campylobacterjejuni isolated from ducks’ chilled carcasses (liver,muscles, cloaca).We used the daily agar culture of bacteria with 1% redblood cells of guinea pigs. Salmonella (1.5×109 CFU/mL)was used as an antigen. Erythrocytes were derivedfrom the blood of a pre-selected donor (guinea pigs).Blood was placed in flasks containing sodium citrateand filtered through a cotton gauze filter to removefibrin and small blood clots. Blood was centrifugedwith sodium chloride isotonic solution four times(1500 rpm, 10 min). Then we introduced it into a 10%suspension of phosphate buffer solution (pH 7.0–7.2).The washed red blood cells were stabilized with0.2% acrolein (acrylic aldehyde) solution in thephosphate buffer (1:1) and incubated in water bathat 37°C for 30–40 min while stirring periodically.Erythrocytes were washed three times by centrifugingwith phosphate buffer at 5000 rpm. To improve thesorption properties of red blood cells, we treated339Kasjanenko S.M. et al. Foods and Raw Materials, 2020, vol. 8, no. 2, pp. 337–347them with tannin, combining equal parts 5% offrozen stabilized red blood cells and tannin solution(1:30 000). The mixture was left in the thermostatat 37°C for 40 min, then it was washed twice withphosphate buffer solution (pH 7.2–7.4) and then twicewith sodium chloride isotonic solution (pH 7.2–7.4).To sensitize the antigen, we used a 1% red blood cellsuspension. Suspensions were left for 24 h at 4°C toexclude spontaneous hemagglutination.The degree of agglutination of the salmonellasisolated was determined by combining preparedsuspended microorganisms and the aqueous solutionof mannan oligosaccharides (0.2, 0.3 and 0.4 g/L) in aratio of 1:1. E. coli O2 test culture was used as a positivecontrol of the agglutination level of the pathogen.One-percent red blood cell suspension in phosphatebuffer solution (pH 7.2–7.4) was used as a negativecontrol [16–18].At the second stage, we studied the influenceof fraction (Aktigen, Alltech Inc.) on the activity,colonization and species composition of the microfloraof young ducks’ intestines. Sixty male ducklingsaged 30 days were used in the study. Each experimentinvolved one control and two experimental groups(50 heads in each). First experimental group wasinfected with Salmonella enteritidis, and the othergroup with Campylobacter jejuni (1×104 CFU/mLper os). Ducklings were kept in sterile boxes on thefloor and fed by standards. They had free access to feedand water. In experimental groups, the birds receiveda prebiotic fraction of MOS (0.4 kg/t) together with thefeed. Ten days after the infection we determined theconcentration of salmonellas, campylobacil, lactobacil,bifidobacterium, and total concentration of anaerobicbacteria using dilution plate counting.At the third stage, we determined the antagonisticactivity of Bifidobacterium spp. (1.0×109 CFU/mL):Bifidobacterium lactis, Bifidobacterium longum,Bifidobacterium bifidum and Lactobacillus spp.(1.0×109 CFU/mL): (Lactobacillus fermentun, Lactobacillussalivarius, Lactobacillus acidophilus againstSalmonella enteritidis and Campylobacter jejuniisolates. Suspensions of bacterial probiotic culturesin a concentration of 1×109 m.c/cm3 were sown onPetri dishes and incubated for 24 h at 37°C. Afterthat, suspensions with microorganisms (Salmonellaenteritidis and Campylobacter jejuni) in a concentrationof 1×109 m.c/cm3 were inoculated by streaking. Thedishes with inoculation were incubated at 37°C for24–72 h. We recorded the diameter of zones with nogrowth of test cultures. To control microbial growth,we used Preston-agar for Campylobacter, “Salmonelladifferent agar” for Salmonella, as well as MPA andMPB for probiotics.We used the Star 53 H.Y. cross ducklings todetermine the effectiveness of probiotics, prebiotics,and their combination. The birds were randomly dividedinto 4 groups, 123 birds in each. Each group included 3flocks, 41 birds in each (12 flocks in total). The controlgroup received the main diet only. Three experimentalgroups received three different supplements in additionto the main diet: bifidobacteria (1.5×109 CFU/mL),mannan oligosaccharides (“Actigen” prebiotic), and acombination of Bifidobacterium spp. and Lactobacillusspp. (1.5×109 CFU/mL) in a ratio of 1:1 and the fractionsof mannan oligosaccharides (0.4 kg/t of feed). Thesesupplements were mannan-rich fractions isolated fromTable 1 Diet compositionIngredients Starter GrowerWheat 55.00 62.00Full fat whole soya 12.00 12.00Soybean neal 23.00 20.00Limestone 0.72 0.50Di-calcium phosphate 1.65 1.85Soybean oil 4.50 5.00Salt 0.20 0.20Sodium bi-carbonate 0.18 0.16DL Methionine 0.50 0.40L-Lysine 0.37 0.30Threonine 0.25 0.13Vitamin-mineral premix 0.50 0.50Nutrient analysis, %, or as indicatedMetabolic Energy, kcal/kg 3000 3125Crude Protein 24.10 22.00Lysine 1.42 1.35Methionine+Cysteine 1.10 0.93Calcium 1.05 0.85AVAILABLE PHOsphorous 0.50 0.42Vitamin-Mineral Premix1Copper, mg 15.00 15.00Iodine, mg 1.00 1.00Iron, mg 30.00 30.00Manganese, mg 112.00 112.00Selenium, mg 0.40 0.40Zinc, mg 105 105Synergen2, g 158 158Vitamin A (IU) 13.00 12.00Vitamin D3 (IU) 4.75 4.50Vitamin E (IU) 70.00 50.00Vitamin K, mg 3.00 2.75Thiamin (B1), mg 3.00 2.50Riboflavin (B2), mg 10.00 8.00Niacin, mg 55.00 50.00Pantothenic Acid, mg 17.00 15.00Pyridoxine (B6), mg 5.00 4.50Biotin, mg 0.30 0.25Folic Acid, mg 2.00 1.70Vitamin B12, mg 200.00 185.00Vitamin C, mg 200.00 200.00Choline, mg 475.00 450.001Vitamin-Mineral Premix manufactured by Target Feeds, Shropshire,UK2Synergen (g) is a commercial enzyme product by Alltech, Inc.340Kasjanenko S.M. et al. Foods and Raw Materials, 2020, vol. 8, no. 2, pp. 337–347Figure 1 Research schemethe cell wall of Saccharomyces cerevisae yeast. Themain diets were prepared at a commercial feed mill andconsisted mainly of wheat and soybean flour, as shownin Table 1 [19, 20].The birds were given starter diets from hatch till day20, grower diets – from day 21 to 49. Feed and water wasprovided throughout the whole study period. Initially,the room temperature was maintained at 30°C for10 days, and then gradually decreased every second dayby 1°C. During the experiment, the lighting regime wasthe following: for 16 h – light, 8 h – darkness, whichlasted 49 days. All conditions were the same for all thefour groups. The birds were weighed when hatched,on days 21 and 49. We also measured feed intake toISOLATING OF SALMONELLA SPP. AND CAMPYLOBACTER SPP.FROM REFRIGERATED CARCASSES OF DUCKS (BS EN ISO 10272:2006)Stage I (In vitro)Studying of Salmonella absorption by mannan-rich fraction isolatedfrom cell walls of Saccharomyces cerevisiae yeastSusceptibility of Bifidobacterium spp.and Lactobacillus spp. to Salmonella and CampylobacterStage II (In vivo)Studying of the effect of mannan-rich fractions on the activity, colonizationand microflora composition in the gastrointestinal tract of ducksInfecting ducks with Salmonella enteritidisand Campylobacter jejuni (1× 104CFU/ml)Experimental groupreceived mannan-rich fractionswith a feed (0.4 kg/t)Control group receivedfeed (base diets)Studying of effect of mannan-rich fractions on the concentrationof the intestinal microflora in the ducks’ cecum, log CFU/gStudying of effect of mannan-rich fractions on the reisolationof S. enteritidis and C. jejuni from infected poultryStage IIIControl group(base diet)Experimental group (basediet with probiotics)Experimental group (base dietwith mannan-rich fractions)Experimental group (basediet with probiotics andmannan-rich fractions)STUDYING OF EXPERIMENTAL DIETSON DUCKS’ GROWTH RATE341Kasjanenko S.M. et al. Foods and Raw Materials, 2020, vol. 8, no. 2, pp. 337–347estimate feed conversion rates and body weight gains.The intact parts of the cecum were withdrawn from 10randomly caught birds aged 49 days immediately aftereuthanasia. The contents of the cecum were placed insterile test tubes. Then, the tubes were instantly frozenin liquid nitrogen, lyophilized and stored at – 80°C forfurther analysis.No principles of the bioethics code were violatedduring the experiments [21].The general scheme of our experimental andpractical studies is shown in Fig. 1.Bacteriological analysis. We tested the laying housesfor Campylobacter spp. before placing the birds thereand on day 21. According to the methods described inBS EN ISO 10272:2006, the swabs were placed in 50 mLof isotonic solution and kept at 260 rpm for one minute[23, 24]. The suspension (0.1 cm3) was then transferredto two dishes with breeding ground (Preston agar basefor Campylobacter) and incubated in microaerobicatmosphere (85% N2, 10% CO2 and 5% O2) at 40.5 ± 1°C.Then we examined them in 44 ± 4 h for typical and/orsuspicious Campylobacter spp colonies.Then, Salmonella enteritidis was isolated from thematerial. The serotyping of Salmonella spp. was carriedout according to the methods with some modificationaccording to the data [28, 32–34].Statistical analysis. Weight gains and feedconversion rates were studied for statistical groupdifferences using the Student’s T-test. The results of themicrobiological analysis were logarithmic and evaluatedfor the statistical difference between the indicators thatwere measurable.RESULTS AND DISCUSSIONThe aim of our research was to study effects ofmannan oligosaccharides fractions and probiotics onSalmonella enteritiadis and Campylobacter jejuni.In vitro experiments showed that 0.2–0.4% aquaticfractions of mannan oligosaccharides could adsorball the Salmonella strains and E. coli O 2 test cultures(positive control).We detected the most active and pronounced abilityto adsorb bacterial pathogens in in vitro experimentswith 0.4% aqueous fraction of mannan oligosaccharides.We recorded the beginning of the adsorption processwithin 2 min. The active process was manifested inthe form of finely-divided sediment and clearing ofthe supernatant. In 8–10 min we observed significantsedimentation (Fig. 2 a–d).The formation of the sediment illustrates theadsorption process that occurred in the test tube.The same process can occur in the gut in animals andpoultry.Intestinal colonization by pathogens begins withthe binding of cells to the epithelium of the intestinalmucosa [17]. Pathogens, including most types ofSalmonella, E. coli, and Campylobacter attach to the gutvia receptors (fimbriae) specific to certain carbohydratescontaining mannose, which localize on the surface ofintestinal mucosal epithelium cells [14].When entering the intestines of poultry with feed,mannan-rich fractions bind to receptors of bacterial cellsthat have type I fimbriae (mannose-sensitive). Fractionsof mannan oligosaccharides are not broken down bydigestive enzymes and are held firmly on the surface ofbacteria. Bacteria with blocked receptors cannot gain afoothold on the surface of epithelial cells – they transitthrough the gastrointestinal tract [13]. Thus, we foundthat the active concentration of mannan-rich fractionscould successfully adsorb Salmonella, a pathogen thatcan cause foodborne diseases.The following experiment examined the effectsof fractions rich in mannanooligosaccharides on theactivity, colonization, and species composition ofmicroflora in ducks’ intestines.At the second (in vivo) stage, we determined theeffect of mannan-rich fractions on the number ofbacteria in the gut of experimentally infected ducks aged30 days by type I fimbriae bacterial strains (C. jejuniand S. enteritidis strains). In experimental groups ofbirds that received prebiotic MOS fractions with feed,the level of bacteria with type I fimbriae decreased. Theeffect of mannan oligosaccharide-rich fractions on theconcentration of intestinal microflora of ducks infectedwith S. enteritidis is shown in Fig. 3.The effect of mannan-rich fractions on theconcentration of intestinal microflora of ducks infectedwith C. jejuni is shown in Fig. 4.The results showed that mannan oligosaccharidescould regulate intestinal microflora due to their selectiveability to inhibit Salmonella spp. and Campylobacterspp. proliferation, preventing pathogenic colonizationof the intestines and minimizing its toxic effect onthe poultry. Concentration of Salmonella spp. in theducklings’ gut was lower by 3.69 log CFU/g andCampylobacter spp. by 3.27 log CFU/g compared tothe control, respectively. Metabolites of functionaloligosaccharides did not affect the levels of intestinalcolonization by pathogenic bacteria (coliforms and(a) (b) (c) (d)Figure 2 Absorption of Salmonella enteritidis with 0.4%concentrated pure fraction of mannan oligosaccharidesin vitro: a – in 2 min; b – in 4 min; c – in 6 min; d – in 10 min342Kasjanenko S.M. et al. Foods and Raw Materials, 2020, vol. 8, no. 2, pp. 337–347anoerobeds). They did not prevent Lactobacillus spp.and Bifidobacterium spp. proliferation either, whichcontributed to the colonization of beneficial bacteria inthe birds’ intestines.Regulation of intestinal microbiocenosis canpotentially have a positive effect on immune responsemechanisms, i.e. to strengthen immunity and enhancethe poultry population.The effect of mannan-rich fractions on the ducklings’gut microflora infected with S. enteritidis is shownin Fig. 4a. The reisolation rate of S. enteritidis andC. jejuni in the test group, which received prebioticmannan-rich fractions with feed, decreased by 53.6 and66.2%, respectively, compared to the control group(Figs. 5a, 5b).Bifido- and lactobacteria also displayed antagonisticactivity against Campylobacter jujuni and Salmonellaenteritidis isolates. It makes them possible to be used forthe prevention of infectious diseases caused by sensitivestrains of pathogens to prebiotic drugs. Bifidobacteriumspp. a nd Lactobacillus spp. suppressed the growth ofmicroorganisms to different extents (Table 2).Twelve isolates (92.6%) of Campylobacter spp. weresusceptible to bifidobacteria. The inhibition zone ofcampylobacter was 5.1 ± 0.3 mm. Ten Campylobacterjujuni isolates showed a moderate level of antagonisticactivity ‒ 76.9%, with the inhibition zone of5.1 ± 1.0 mm.Twenty four isolates (88.9%) of S. enteritidis weresusceptible to bifidobacteria; the inhibition zone ofS. enteritidis was 5.5 ± 0.4 mm. The antagonisticactivity of lactobacilli against S. enteritidis showed amoderate level: 22 isolates (81.5%) had inhibition zoneof 4.9 ± 0.5 mm. Bifidobacteria were more active againstCampylobacter spp. and Salmonella spp. It makes itpossible to use probiotics to prevent and treat infectiousdiseases caused by susceptible strains of pathogenicmicroorganisms to the drug. To improve the ducks’productivity, we studied the effect of mannan-richfractions. The experiment plan is given in Table 3.To solve the problem of bacteriosis prevention andincrease of birds’ productivity, we also studied the effectof a combined use of mannan oligosaccharides andprobiotic bifidobacteria and lactobacilli.Figure 3 Effects of mannan oligosaccharide-rich fractions on the concentration of intestinal microflora of ducks infected withS. enteritidis log CFU/g(а) (б)5.646.99 6.569.34 9.14 9.727.34 7.288.69.69024681012Salmonella spp. Lactobacillusspp.Bifidobacteriumspp.Coliforms Anaerobeslog CFU/gIntestinal microfloraExperiment Control5.766.99 6.569.03 9.14 9.727.34 7.288.69.69024681012Campylobacterspp.Lactobacillusspp.Bifidobacteriumspp.Coliforms Anaerobeslog CFU/gIntestinal microfloraExperiment Control72.518.9020406080Ducks infected with S.enteritidis, %Control Experimental89.823.6020406080100Ducks infected with C. jejuni, %Control Experimental(а) (б)5.646.99 6.569.34 9.14 9.727.34 7.288.69.69024681012Salmonella spp. Lactobacillusspp.Bifidobacteriumspp.Coliforms Anaerobeslog CFU/gIntestinal microfloraExperiment Control5.766.99 6.569.03 9.14 9.727.34 7.288.69.69024681012Campylobacterspp.Lactobacillusspp.Bifidobacteriumspp.Coliforms Anaerobeslog CFU/gIntestinal microfloraExperiment Control72.518.9020406080Ducks infected with S.enteritidis, %Control Experimental89.823.6020406080100Ducks infected with C. jejuni, %Control ExperimentalFigure 4 Effects of mannan oligosaccharide-rich fractions on the concentration of intestinal microflora of ducks infected withC. jejuni log CFU/gLactobacillusspp.Bifidobacteriumspp.Campylobacterspp.Lactobacillusspp.Bifidobacteriumspp.Campylobacterspp.343Kasjanenko S.M. et al. Foods and Raw Materials, 2020, vol. 8, no. 2, pp. 337–347The first stage of the experiment included 20320ducks (Star 53 Y.Y.) divided into four groups: one controland three experimental ones. The experiment wascarried out three times (81280 ducks in total). Probioticswere added to the diet of the ducks with water (10 cm3per 4 kg duck weight) once a day from the first day untilthe end of the fattening period (49 days).We added mannan-rich fractions to the base diet –400 g/t of feed. We added bifidobacteria and mannanrichfractions to the duck diet once a day until the end offattening period (49 days). The analysis showed higherresults during all periods of the birds’ life compared tothe control groups (Table 4).At the age of 21 days, the average growth rate ofducks receiving probiotics with mannan-rich fractionswas 87.3 g vs. to 83.6 g in the control group. Wenoticed a similar trend at the age of 21 days with anaverage daily growth of ducks from 101.4 g to 107.6 g.The experimental group III after 21 days exceeded thecontrol group by 7.6%.On day 21, the body weight of ducks receivingprobiotics, mannan-rich fractions, and their mixexceeded that in the control group by 1.1, 1.9 and3.6%, respectively. The body weight was 1273 ± 67 g,1283 ± 42 g, and 1305 ± 34 g, respectively.In 49 days, the body weight of the ducks receivingmannan-rich fractions, as well as their mix was3415 ± 95.5, 3459 ± 87.4, and 3547 ± 24.3 g, respectively,which exceeded the weight of the ducks of the controlgroup by 3.1, 4.4 and 7.1 % (Table 4). In addition, asimilar trend was detected with average daily gain induck weight. In 49 days, it was 59.2, 59.7, and 61.3 g forexperimental groups, exceeding that in the control groupby 1.2, 2.1, and 4.7 %, respectively. The ducks receivingthe mix of probiotics and mannan-rich fractions gainedweight more intensively compared to the birds having theother diets (Table 5).CONCLUSIONIn vitro studies showed the ability of prebioticmannan-rich fractions isolated from the cell wallsof Saccharomyces cerevisiae yeast to adsorb type Ifimbriae bacterial pathogens (S. enteritidis and C. jejuni)and prevent colonization and proliferation of pathogenicmicroorganisms on the surface of ducks’ intestinalepithelial cells.We studied the influence of fractions rich inmannan oligosaccharides on activity, colonization,and species composition of duck gut microflora.(а) (б)Figure 5 Effects of mannan-rich oligosaccharides on the reisolation rate of salmonellas from the intestines of poultry infected withS. Enteritidis (a) and campylobacteria from the intestines of poultry infected with C. Jejuni (b)(а) (б)02Campylobacterspp.Lactobacillusspp.Bifidobacteriumspp.Coliforms AnaerobesIntestinal microfloraExperiment Control72.518.9020406080Ducks infected with enteritidis, %Control Experimental89.823.6020406080100Ducks infected with C. jejuni, %Control Experimental(а) (б)0Campylobacterspp.Lactobacillusspp.Bifidobacteriumspp.Coliforms AnaerobesIntestinal microfloraExperiment Control72.518.9020406080Ducks infected with S.enteritidis, %Control Experimental89.823.6020406080100Ducks infected with jejuni, %Control Experimental(а) (б)0Campylobacterspp.Lactobacillusspp.BifidobacteriumColiforms AnaerobesIntestinal microfloraExperiment Control72.518.9020406080Ducks infected with S.enteritidis, %Control Experimental89.823.6020406080100Ducks infected with C. jejuni, %Control ExperimentalTable 2 Susceptibility of Bifidobacterium spp. and Lactobacillus spp. (M ± m), %Microorganism Inhibition zone, mm Control of growthon Preston agarControl of growth on SalmoBifidobacteriumspp. Lactobacillus spp. nella agar M1078, HiMediaC. jujuni 5.3 ± 0.2 5.1 ± 0.3 +S. enteritidis 5.5 ± 0.4 4.9 ± 0.5 +(+) – signs of growth, P < 0.05Table 3 Bifidobacteria and mannan-rich fractions in the duck’sdiet (n = 20320)Groups DietControl Base diet “Starter” from day 1 to day 20 of lifeBase diet “Grower” from day 21 to day 49Experimentalgroup IBase diet + probiotics from day 1 to day 49Experimentalgroup IIBase diet + mannan-rich fractions fromday 1 to day 49Experimentalgroup IIIBase diet + probiotics + mannan-rich fractionsfrom day 1 to day 49S. Enteritidis, % C. Jejuni, %344Kasjanenko S.M. et al. Foods and Raw Materials, 2020, vol. 8, no. 2, pp. 337–347S. enteritidis reisolation rate decreased by 53.6% andC. jejuni ‒ by 66.2% in ducks receiving fractions richin mannanooligosaccharides, compared to the controlgroup. Experiments showed that the addition of prebioticfractions to the diet did not affect the concentration oflactobacilli, bifidobacteria, enterococci, and anaerobicbacteria.Bifido- and lactobacteria have antagonisticactivity against circulating strains of S. enteritidis andC. jejuni. 88.9% of S. enteritidis isolates weresusceptible to bifidobacteria and 81.5% of the studiedstrains were susceptible to lactobacilli. 92.6% of theisolated Campylobacter jejuni were susceptible tobifidobacteria, 76.9% of Campylbacter strains weresusceptible to lactobacteria.We developed a method of preventing bacterialinfections and increasing ducks’ productivity basedon the combined use of bifido- and lactobacteria(1.5×109 CFU/mL) in a ratio of 1:1 with water andfractions enriched with mannan oligosaccharides(0.4 kg/t) together with feed. We recommend thepreparation from the first day of birds’ life till the end ofgrowing period.Preventive measures improved the preservationof the duck population by 8.76%, ensuring the averagedaily increase by 6.9% and the reduction of feed costs byTable 4 Effect of experimental diets on duck growth (M ± m)Indexes GroupsControl(base diet)Experimentalgroup I(diet withprobiotics)Experimentalgroup II (dietwith mannanrichfractions)Experimentalgroup III (diet withprobiotics and mannan-rich fractions)Days 0–21number of birds on day 1 20320 20320 20320 20320average body weight of ducks, gaverage body weight of ducks,%1259 ± 45*1001273 ± 67*101.11283 ± 42*101.91305 ± 34*103.6average daily gain of ducks, gaverage daily gain of ducks,%83.6 ± 8.410084.8 ± 8.1101.485.7 ± 9.5102.587.3 ± 8.2107.6safety of poultry,% 91.3 92.4 93.46 104.4Days 22–49number of birds on day 22 18552 18703 18991 19537average body weight of ducks, gaverage body weight of ducks,%3312 ± 35.3*1003415 ± 95.5*103.13459 ± 87.4*104.43547 ± 24.3*107.1average daily gain of ducks, gaverage daily gain of ducks,%58.510059.2101.259.7102.161.3104.7number of birds on day 49, headsnumber of birds on day 49, %1653789.141735392.781806095.101912797.9cost of feed 97644.3 103216.7 104128.4 105331.7feed consumption per 1 kg of growth for 49 days, kgfeed consumption per 1 kg of growth for 49 days, %2.01100.01.9191.521.8893.531.8695.02*The values in the column for each treatment stage that does not share the overall upper index vary significantly (P < 0.05). Each value is anaverage of n = 3 flocks per diet with 36, 30 and 30 birds in the flock for each growing period, respectively. Comparisons between the groups weremade using the Tukeys HSD test, P < 0.05 we considered statistically significantTable 5 Average body weight of ducks receiving probiotics and mannan-rich fractions during different periods of growthand development, g/head (n = 50)Age,weeksGroupsControl (base diet) Experimental group I(diet with probiotics)Experimental group II(diet with mannan-richfractions)Experimental group III(diet with probiotics andmannan-rich fractions)Standardvalues0 52.35 ± 0.57* 52.64 ± 0.37* 53.22 ± 0.67* 52.66 ± 0.81* 521 205.52 ± 1.43* 206.53 ± 0.58* 208.42 ± 0.37* 215.53 ± 0.48* 2062 640.37 ± 2.93* 642.34 ± 3.25* 645.38 ± 5.34* 678.59 ± 13.73* 6453 1239.17 ± 5.52* 1247.72 ± 5.51* 1258.42 ± 14.53* 1305.48±34.27* 12574 1814.58 ± 7.74* 1874.25 ± 22.47* 1883.58 ± 11.43* 1933.53 ± 31.45* 18765 2351.34 ± 33.34* 2404.43 ± 27.48* 2486.35 ± 42.28* 2592.63 ± 47.81* 25036 2918.42 ± 27.56* 2948.27 ± 25.58* 2915.37 ± 33.59* 3197.37 ± 49.56* 31007 3319.68 ± 26.85* 3419.62 ± 24.37* 3528.63 ± 25.57* 3683.87±25.79* 3500345Kasjanenko S.M. et al. Foods and Raw Materials, 2020, vol. 8, no. 2, pp. 337–3474.98% for 1 kg of growth throughout the growing period.During the experiment, we recorded a significantdecrease in Salmonella and Campylobacter colonizationin the poultry intestines and improved average dailygrowth. The biologically active supplements provided asignificant advantage in industrial duck farming.We demonstrated the effectiveness of natural andenvironmentally safe methods: yeast fractions rich inmannan oligosaccharides, probiotics, and their combineduse. The method was effectively implemented inUkrainian poultry farms.CONTRIBUTIONConcept – O.I. Kasjanenko, L.V. Nagornaya,S.M. Kasjanenko; Design – V.V. Melnychuk,S.M. Kasjanenko; Observation – O.I. Kasjanenko,V.A. Yevstafieva; Resources – S.M. Kasjanenko;Materials – V.A. Yevstafieva, L.V. Nagornaya,S.M. Kasjanenko; Data collection and/or processing –S.M. Kasjanenko, O.I. Kasjanenko, L.V. Nagornaya,V.A. Yevstafieva; Analysis and/or interpretation –O.I. Kasjanenko, L.V. Nagornaya, V.V. Melnychuk,V.A. Yevstafieva; Search for literature –O.I. Kasjanenko, S.M. Kasjanenko, V.V. Melnychuk,G.A. Lukyanova, I.A. Gurenko; Writing the manuscript– O.I. Kasjanenko, L.V. Nagornaya, S.M. Kasjanenko,G.A. Lukyanova, I.A. Gurenko; Critical review –O.I. Kasjanenko, G.A. Lukyanova, I.A. Gurenko.CONFLICT OF INTERESTThe authors have no conflict of interest.ACKNOWLEDGEMENTSThe authors thank the managers of the poultry farmsfor their assistance in conducting experiments.