Effect of Black Soldier Fly (Hermetia illucens L.) Fat on Health and Productivity Performance of Dairy Cows

Due to the intensive development of technologies for obtaining protein, energy feed and biologically active supplements from insects, the feasibility and effectiveness of introducing these products into the rations of farm animals require further study. This research aims to study the possibility and effects of feeding dairy cows fat from the larvae of the black soldier fly (BSFLF). The composition and properties of the BSFLF have been studied. The research of the fatty acid composition of BSFLF showed a high content of saturated fatty acids, including 58.9% lauric acid. The experiment was performed on black-and-white cows at the beginning of lactation (control, D0 (n = 12) vs. experimental D10 (n = 12) and D100 (n = 12) groups, 10 and 100 g/head/day BSFLF, respectively. There was no negative effect of BSFLF feeding on the process of feed digestion. The pH of the rumen content decreased (6.80 ± 0.07 & 6.85 ± 0.09 vs. 7.16 ± 0.06, p < 0.05), with an increase in the number of infusoria (0.27 ± 0.03&0.37 ± 0.09 vs. 0.18 ± 0.03 g/100 mL, p = 0.16); there was an increase in the concentration of VFA in the rumen content of animals of the experimental groups by 2.1 (p < 0.05) and 3.81 (p < 0.01) (8.66 ± 0.46 & 10.37 ± 0.42 vs. 6.56 ± 0.29) mmol/100 mL. The average daily milk yield of Group D10 cows over the experimental period (d17−d177) was slightly higher than the control (by 4.9%, p = 0.24 vs. Group D0). At the same time, Group D100 cows showed a significant increase in natural-fat milk compared to controls (by 8.0%, p < 0.05 vs. Group D0) over the same experiment period. Analysis of the fatty acid composition of the milk of the experimental animals showed some changes in the fatty acid composition of milk under the influence of BSFLF feeding; these changes were especially noticeable in Group D10. Thus, it was found that feeding dairy cows BSFLF at different dosages leads to better indicators of pre-gastric digestion and productivity.

PSIX-11 Bacterial clinical mastitis associated with abortion in dairy cows

Within the period from 20.04.2020 to 15.02.2021 the state of 2087 pregnant cows was studied to identify the connection between abortions and the occurrence of mastitis. During the study period 97 cases of clinical mastitis and 149 cases of abortion were identified. Abortions were observed in 42 out of 97 cows with registered clinical mastitis. It was found that cows that had a clinical form of mastitis during the first 45 days of pregnancy (in the embryonic period of development) subsequently had the maximum number of abortions - 27 heads or 64.28% of abortions of cows with mastitis. Among cows that had mastitis in the period of 46–150 days of pregnancy 13 cases of abortion were revealed (30.9% of abortions of cows with mastitis). Among cows that had mastitis during pregnancy for more than 150 days 2 cases of abortion were detected (4.7% of abortions of cows with mastitis). On the basis of bacteriological analysis, Staphylococcus spp., Streptococcus spp. and Enterobacteriaceae were isolated from milk of 15 aborted cows with the diagnosis of clinical mastitis. To identify species the conventional biochemical methods were applied together with the API 20 E, API Staph, API 20 Strep test (bioMerieux SA, France). In total, 18 species of pathogens were identified, including Ps. aeruginosa (n = 5), E. coli (n = 4), S. aureus (n = 1), S. saprophyticus (n = 8). Ps. aeruginosa, E. coli, S. aureus were isolated both from the organs of the reproductive system and from the milk of the cows who had had abortions after suffering from mastitis, whereas no relationship was found between the microflora of the reproductive system and the udder of the cows whose abortions are not associated with mastitis. The study was supported by the Russian Science Foundation, project No.20-16-00106

PSX-B-21 Diagnosis of early mastitis in dairy cows: Somatic cells and bacterial pathogen measuring

Mastitis is an inflammatory condition of the breast that can be caused by chemical, physical, traumatic injury or bacteria. In recent years, biomarkers for the mastitis diagnosis have been actively studied. The aim of the study was to assess the relationship between SCC and pathogenic bacteria in milk occurrence. The study carried out by milk samples collected in the experimental herd (Krasnodar region, Russia) from 85 Holsteinized Black-and-White cows. Healthy cows (HC; n = 4), cows at risk for clinical mastitis (RCM, n = 22), subclinical (SCM; n = 25) and clinical mastitis (CM; n = 34) groups were divided by a bacteriological cultivation and SCC level (Fossomatic7 DC). SCC results were logarithmically converted to SCS. Consequent groups were included animals with SCS level: HC (SCS &lt; 4.1), RCM (4.2≤SCS≤5.3), SCM (5.4≤SCS≤6.3), CM (SCS &gt;6.4). HC group of animals showed SCS equal to 3.11±0.28, 4.85±0.44 for RCM, 5.8±0.28 for SCM and 7.43±0.87 for CM. Identification of isolated bacteria species was carried out by conventional biochemical methods using the API20E, APIStaph, API20Strep tests (bioMerieux SA,France). Number of isolated pathogenic bacteria in CM group was 57 strains of which 33.3% were attributed to Enterobacteriaceae, 45.6% to coagulase-negative staphylococci (CONS), 12.3% to S.aureus and 8.8% to Ps.aeruginosa. In SCM group there were assigned 48 strains: 32.5% to Enterobacteriaceae strains, 42.5% to CONS, 20.0% to S.aureus, 5.0% to Ps.aeruginosa. The antibiotic susceptibility was determined according to NCCLS and EUCAST. S.aureus isolates showed the highest sensitivity to erythromycin (4.3% of resistant strains) and the highest resistance to ciprofloxacin (100%), tetracycline (95.0%), rifampicin (88.5%), benzylpenicillin (79.3%), novobiocin (69.2%) and fusidin (65.5%). The primary analysis of SCC and milk microbiological profile can be able to increase the accuracy of mastitis occurrence diagnosing that contributes to taking the right decision for choosing an antibiotic to preserve the cows’ health in Russian cattle population. The study was funded by RSF (project No.21-76-20046)

PSX-B-14 Properties of Kluyveromyces marxianus strains isolated from natural biotopes

Kluyveromyces marxianus yeast is often isolated from dairy products and used as probiotic agents in food. As a producer-yeast they must be genetically stable, have simple nutrient requirements, be effective in hostile conditions, grow on inexpensive nutrient media and be easy to store and distribute. Nineteen strains of K. marxianus isolated from natural biotopes were tested for their ability to grow on various carbon sources. For this, the YPD medium (1% yeast extract, 2% peptone, 2% dextrose, pH 5.5) was used with the addition of 20 g/L of one of the following carbon sources: glucose, sucrose, lactose, maltose, mannitol, arabinose, xylose, and galactose. The cultivation was carried out for 1–3 days. All isolates were also tested for their ability to grow in YPD broth at different temperatures (4, 27, 37, 40, 42, 46 and 48 °C) and pH (5; 3 and 2). K. marxianus strains showed widespread use of the substrate and high resistance to elevated incubation temperatures. All tested strains grew at 27 and 37 °C and one strain grew at 46 °C. None of the strains showed active growth at pH 2 and all cultures grew actively at pH 3. At the same time five strains showed growth at pH 5.0. All strains fermented galactose, 16 - xylose, 9 - glucose, 7 - lactose, 12 - maltose, 11 - arabinose, 5 - sucrose, 13 - mannitol. It should be noted that all strains in this study have showed fully restored growth after 2 hours’ incubation at pH 2. It indicates that they could survive when passing through the gastric passage into the intestine. These properties make the use of K. marxianus and its metabolites indispensable in agriculture as a feed additive. This work was supported by the Ministry of Science and Higher Education of Russia.

PSXVI-14 Study of the antagonistic properties of C. utilis in relation to the resident microflora of the animal organism

C. utilis yeast is widely used in industry for the production of fodder protein, amino acids, vitamins, and enzymes. We have studied the antimicrobial activity of C. utilis CY 302 against such collection strains as E. coli 3912/41, S. flexneri 1a 8516, S. enterica serovar Typhimurium 79, S. epidermidis ATCC 14990, S. aureus ATCC 25923, Proteus vulgaris HX 19 222, L. casei subsp. Rhamnosus ATCC 7469, B. breve ATCC 15701, C. albicans ATCC 10231 by using the agar blocks method and by measuring the inhibition growth zone (IGZ, mm) accompanied by the target cells death zone. The yeast strain was grown on Sabouraud’s medium at 28±1 °C for 3 days, and the test cultures were grown on differential diagnostic media for each bacterial species (HiMedia Laboratories Pvt. Ltd, India) at 35±2 °C overnight. The analyses were done separately for each culture. A weak antimicrobial effect was observed with respect to L. casei and B. breve, the IGZ was 5.0 and 4.0 mm, respectively. The halos of inhibition against pathogenic bacteria were 7 mm for E. coli, 5 mm for S. typhimurium, 5 mm for P. vulgaris, 6 mm for S. fiexneri, 6 mm for S. aureus, and 5 mm for S. epidermidis. After incubation there was noted the absence of DZZR in the wild C. utilis CY 302 strain in relation to the C. albicans ATCC 10231 strain from the collection. As a result of the studies the antagonistic potential of the yeast isolate C. utilis CY 302 was revealed. The work was supported by the Ministry of Science and Higher Education of Russia.

Changes in the Microbiome of Milk in Cows with Mastitis

Analysis of milk micrbiomes from healthy cows and cows with different (clinical and subclinical) forms of mastitis was performed at two farms of the Central Russia. An increase in the operational taxonomic units (OTUs) of bacteria of the phylum Proteоbacteria belonging primarily to Pseudomonadales, Burkholderiales, as well as Streptococcaceae, Staphylococcaceae, and Bacillaceae in the animals with mastitis was detected. The Planococcaceae OTU percentage decreased. The ratio of rarely presented OTUs also changed in the milk of animals with mastitis.

PSIX-13 Influence of an integrated fodder additive on productivity and metabolic homeostasis of dairy cattle in transition period

The transition period is the most stressful for dairy cows in terms of metabolic rate and characterized by dynamic changes in the hormonal profile, loss of appetite, negative energy balance, nutrient and vitamin deficiencies, compromised immunity and oxidative stress. The aim of the research was to balance the increase in cows’ productivity and the consumption of nutrients from the feed during the transition period through the use of energy feed additives (EFS), high protein feed concentrate (PFC) in combination with biologically active (BA) substances. Thirty-six dairy cows of black-motley breed were divided into 3 groups: (1) The main diet (G0, n = 12), not supplemented with additives, (2) additive 1 (G1; supplemented with 0.5 kg EFS / cow per day, n = 12), (3) additive 2 (G2; supplemented with 0.5 kg EFS; 0.5 kg PFC and 0.06 kg BA / cow per day, n = 12). The experimental part of the feeding lasted for 20 days before calving and the first 100 days after calving (DPP). Blood samples were collected during the first and the third months after calving. The biochemical analyzer was used to measure blood serum components. The milk yield was recorded monthly throughout lactation. BCS losses from 7 days prior to calving to 28 DPP were -0.29 for Gr2, -0.42 for Gr1 and -0.60 for Gr0. Feeding with additive 2 (Gr2) increased milk yield (p≤0.05) in the first 100 DPPs and (p≤0.001) 305 DPPs compared to G0. The number of samples with SCC ≥ 500 000 / ml. per 100 DPP was 51% in the Gr0 group, 27% in Gr1, 25% in Gr2. Also, microbiological control showed an excess of Bacterial cells in the milk of cows from group G0, which correlates with SCC indicators. Cows from Gr2had a lower content of ketone bodies (P≥0.001) and higher (P≥0.001) antioxidant activity of blood serum compared to Gr0. Cows from Gr2 had an increase in ALT activity by1.4 times (P &lt;0.05) from the first to the third months after calving.

PSV-30 Influence of crossbreeding on meat production, growth, meat quality, and carcass traits within sheep fed the same diet

The aim of this study was to determine the effect of crossbreeding on meat production traits of sheep. Purebred (Volgograd breed, n = 30) and crossbred (F3, Volgograd x ¼ North Caucasian breed, n=30) sheep were fed for 60 days from the age of 8 months. The diet was the same for both groups and included: a dry fodder of mixed herbs, green-cut fodder, stock feed of barley, and salt. The initial liveweight for purebred sheep was 42.39±0.38 kg and for crossbred sheep was 44.41±0.47 kg (P &lt; 0.01). The final liveweight for purebred sheep was 50.10±0.43 kg. Crossbred sheep were heavier at 52.40±0.36 kg (P &lt; 0.001). The weight of carcasses was greater for crossbred sheep at 22.87±0.53 kg (P &lt; 0.05) and 20.67±0.76 kg for purebred sheep. Compared with purebred sheep, crossbred sheep had a lower amount of internal fat (0.92±0.27 kg vs. 1.18±0.35 kg). The weight of meat from purebred sheep was less than crossbred sheep (16.12±0.63 kg vs. 18.28±0.43 kg, P &lt; 0.05) while the weight of bone was almost the same (4.55 vs. 4.59 kg). Consequently, the ratio of meat/bone was 5.54 vs. 3.98. The food energy value for the meat of purebred sheep was greater at 259.36±16.78 kcal than the meat of crossbred sheep at 233.85±11.10 kcal. Total moisture in the meat of purebred sheep was lower (60.11±0.67 vs. 63.05±0.65, P &lt; 0.05), total protein was a little higher (17.71±0.77 vs. 17.63±0.24), and lipids were higher (20.73±0.73 vs. 17.89±0.82, P &lt; 0.05) than in the meat of crossbred sheep. The meat of purebred sheep had a lower concentration of non-replaceable amino acid (12.47 g) compared with meat of crossbred sheep (17.20 g), and a lower concentration of replaceable amino acid (23.08 g vs. 26.84 g). The results of this study can be used to improve meat production and meat quality.

PSVIII-12 Estimations of treatment schemes efficiency of bacterial mastitis in dairy cow and antibiotic resistance of identified pathogens

The research was done on the herd (n = 3000) of cows of black-motley breed with an admixture of Holstein. At the first stage, the diagnosis was carried out by using the Keno test. There were selected 148 (4.9%) cow, which had of subclinical mastitis. For treatment, there were used the schemes tried and tested in the farm: (1) nisin, polymexin B, ketoprofen, methyl salicylate; (2) nisin, polymexin B, ketoprofen, ceftiofur; (3) amoxicillin, ketoprofen, methyl salicylate, prednisone. Before it, the allocation of pathogens was not carried out. After treatment the number of repeated cases of the disease reached 44.6%, which indicated the ineffectiveness of the treatment regimens used. At the second stage, samples of milk, nasal and vaginal mucus were taken from animals with a relapse of mastitis. Different pathogens were used to isolate pathogens (Staphylococcus aureus, Escherichia coli, Shigella spp., Enterococcus spp., Ps. aeruginosa). The extracted isolates were identified based on the cultural and biochemical properties. The results were interpreted on the recommendation of EUCAST. Of all the animals examined, they simultaneously detected in milk 3 pathogens in 37.8%, 2 pathogens in 40.9%, and only one pathogen was isolated in 21.3%. Moreover, S. aureus (84.8%), Ps. aeruginosa (62.1%), Enterococcus spp. (34.8%) was found in smears from the vagina. The sensitivity of the selected pathogens to antimicrobials showed that 73% of S. aureus strains were resistant to ≥6 antibiotics, 47% E. coli to ≥7, 34% Shigella spp. to ≥4 and 21% Ps. aeruginosa to ≥4. The use of antibiotics of different groups without isolating the pathogen and determining its sensitivity leads to the appearance of multiresistant strains of bacteria and culling animals from the herd. This work was supported by the Ministry of Science and Higher Education of Russia (AAAA-A18-118021590136-7) and the Russian Science Foundation (project 20-16-00106).

PSX-40 Late-Breaking Abstract: Effect of Dietary Replacement of Fishmeal by Insect Meal on Growth Performance and Non-specific Immunity of Growing Pigs

Recent data show that dried larvae of darkling beetles (Zophobas morio L., DZML) and dried larvae of wax moths (Galleria mellonella L., DGML) contains a significant amount of protein, fat, chitin, melanin, antimicrobial peptides, trace elements etc. Larva’s fat is rich in lauric and other medium-chain fatty acids. The aim of our research was to study the influence of dietary replacement of fishmeal (FM) by insect meal on growth performance and nonspecific immunity of growing pigs. Experiments were performed using crossbred [(BWxL)xD] pigs (BW1=14.39±0.19 kg, N=27, n = 9) during the growing period. Animals were allocated to 3 groups: 1 – control (standard feed (SF), including FM), 2 – experimental (SF+2.5%DZML), 3 – experimental (SF+3.0%DGML). The materials obtained in the experiment was biometrically processed using the ANOVA method (at P &gt;0.05 or P &lt; 0.05). The use of DZML&DGML in feed didn’t reduce ADG of experimental animals during the growing period (413.23&413.76 vs. 413.76 g) compared to the control group. Dried larvae supplementation didn’t reduce feed intake and nutrient digestibility. The fat digestibility increased in the 2&3-experimental group (45.0&44.36 vs 29.75%, P &lt; 0.05), due to the high level of lipids and the profile of fatty acids in the larvae. Biochemical blood test showed a higher ALB/GLB ratio (0.85&1.43 vs 0.59, P = 0.05), higher number of WBC (12.36&12.89 vs. 10.44, P = 0.19) in the blood of the experimental animals compared to the control group. Growing pigs of the experimental groups had a higher level of nonspecific immunity, which is expressed in an increase in bactericidal, lysozyme activity of blood serum and phagocytic activity of neutrophils. Consequently, it is possible to consider the prospects of using DGML&DGML as dietary supplements to diets of growing pigs. The work was supported by the GZ АААА-А18-118021590136-7 of the Ministry of Science and Higher Education of the Russian Federation.

PSIX-14 Influence of living yeast of the genus Rhodotorula against probiotic and pathogenic bacteria

The aim of the research was to study the effect of live yeast Rhodotorula spp. (LYR) on the growth and development of microorganisms and microbial profiles in batch culture. A liquid medium was used to prepare the inoculum (20 g/L glucose, 20 g/L peptone, 10 g/L yeast extract). The study in vitro was a 3×5 factorial arrangement, including low (5.0) and high media pH (7.5) and temperature (from 20 to 39 ° C). The treatments were LYR with concentrations from 1·103 to 1·1011 CFU/ml. The bacteria were selected: Lactobacillus casei subsp. Rhamnosus ATCC 7469, Bifidobacterium breve ATCC 15701, E. coli ATCC 25922, Staphylococcus aureus ATCC 25923, Staphylococcus epidermidis ATCC 14990. The analyses were carried out separately for each culture and LYR concentration by broth dilution. For incubation were used Saburo agar for LYR and differential-diagnostic media for each bacterial species. After incubation, there was a lack of growth of E. coli, S. aureus and S. epidermidis in LYR concentrations from 1·109 to 1·1011 CFU/ml at the temperature of 28±0.5 °С, while the number of yeast cells did not decrease. At the temperature above 32±0.5 °C there was a decrease in the amount of LYR by more than 1000-fold in the samples of all cultures. The presence of LYR in the medium led to an increase (p≤0.001) in the number of L. casei at pH 5.0 and temperature less than 30±0.5 °С. Unlike L. casei, the viability of the B. breve culture has decreased (P ≤0.05) by 200 times at pH 5.0, but has increased (p≤0.001) by more than 1000 times at pH 7.0. The optimal cultivation temperature was 36±0.5 °С. These results indicate the multidirectional effect of LYR on microorganisms in vitro. This work was supported by the Ministry of Science and Higher Education of Russia (topics GZ AAAA-A18-118021590136-7).

Exotoxin diversity of Staphylococcus aureus isolated from milk of cows with subclinical mastitis in Central Russia

Mastitis, a major veterinary problem widespread in many regions, is caused mainly by Staphylococcus spp. However, there is no current reliable information about the role of Staphylococcus aureus and their toxins in the development of mastitis in cows in the territory of the Russian Federation. The aim of this investigation was to determine the profile of exotoxins of S. aureus from cow milk from farms of Central Russia. A total of 60 isolates of S. aureus were obtained from milk samples of cows with the subclinical form of mastitis. The exotoxin genes were identified using 2 types of PCR assays. The diversity of enterotoxin genes was studied by multiplex PCR. The percentage occurrence of enterotoxin genes was as follows: sea, 53.3%; seb, 3.3%; sec, 50%; sed, 4%; see, 46.6%; seg, 70%; sei, 10%; selp, 3.3%; and tsst1, 1.6%. The seh gene was not detected. The genes of pore-forming toxins and phenol-soluble modulins were identified by singleplex PCR and consisted of the following: hlA, 70%; lucS, 46.6%; psmA, 81.6%; psmB, 95%; and hld, 78.3%. The most abundant genes were psm (psmB, 95%), which codes for pore-forming toxins, and seg (70%), which codes for enterotoxins. The production of some enterotoxins in bacterial culture medium was detected by ELISA. The level of toxin production was near 1 ng/mL for SEA, SEE, SEG, SEI, SELP, and TSST-1 and reached a maximal level of 18 ng/mL for SEE. In the present work, we show that subclinical mastitis in cows is associated with S. aureus in the central region of the Russian Federation. Most of the isolates containing enterotoxin genes also had cytotoxin genes.