Gut bacteria play an important role in poultry nutrition and the immune defense system. Changes in the intestinal microbiome affect the physiological state, metabolism and innate im-munity of poultry. The present study aimed to characterize age-related changes in the gastrointestinal tract microflora in broiler chickens, depending on supplementation of the diet with the in-feed antibiotic Stafac® 110 and a Bacillus subtilis strain-based probiotic. In this regard, a comprehensive analysis of the taxonomic structure of the microbial community in the gastrointestinal tract (GIT) of broiler chickens was carried out using a molecular genetic technique of the Terminal-Restriction Fragment Length Polymorphism analysis and taking into account age dynamics and feeding treatment. A beneficial effect on the microbiological composition and body weight of broilers was observed when using the antibiotic and probiotic in compound feeds. Different bacterial communities were revealed in the duodenum and cecum and their positive impact on broiler growth was established. The results obtained shed light on the formation of GIT microflora of broiler chickens during the growing period and its changes in response to the use of the antibiotic and the probiotic. We suggest that the implementation of the tested in-feed antibiotic and probiotic can be beneficial in regulating the intestinal microflora microbiological processes in the GIT and improving the feeding efficiency and productivity of broiler chickens.

Although the herbicide glyphosate is widely used globally and considered safe, more evidence of its adverse effects on animals and humans is accumulating. The present investigation was aimed at evaluating the impact of different glyphosate concentrations on zootechnical characteristics and clinical, biochemical and immunological blood parameters in Ross 308 broiler chickens. Four groups were employed, including untreated control and three experimental groups fed diets enriched with glyphosate at doses of 10, 20 and 100 ppm that conformed to 0.5, 1 and 5 maximum residue limits, respectively. The results showed that glyphosate is a stress factor triggering a multifaceted effect on important blood parameters (e.g., white blood cell and phagocytic counts), which was shown for the first time in the experiments involving productive meat-type poultry. It was first revealed that glyphosate-induced changes in blood parameters may be related to a negative impact on the zootechnical characteristics including the digestive tract organ development and body weight gain. The study findings suggested that exposure to glyphosate in the feedstuffs can adversely affect the physiological condition and productivity of broilers.

The purpose of this research is to develop and test a new approach to prevent clostridial disease in cattle, based on the use of a new compound biologically active feed additive (BFA). Some properties of the separate components of BFA are characterized. The research showed that a strain of the bacterium Bacillus amyloliquefaciens159 has an expressed antagonism to toxin-producing strains of C. perfringens. When using the test strains of C. perfringens from the ATCC collection (13,124 as type A, 10,543 as type C, 12,916 as type F), the anticlostridial activity of the tested strains varied, with size range of 14.0 ± 0.95–15.0 ± 1.28 mm of delayed growth zones. The bactericidal properties of lauric acid and the sorption properties of diatomaceous earth, included in BFA, were confirmed. The experiment was conducted on Holstein cows at the beginning of lactation (control, C (n = 15) vs. experimental E48 (n = 15), E80 (n = 15) and E112 (n = 15), 48, 80 and 112 g/head/day BFA, respectively. All cows were vaccinated with “Coglavax” (vaccine against bovine and sheep clostridial disease, Ceva-Phylaxia VeterinaryBiologicals, Hungary), reinjected two weeks before the experiment. At the end of the experiment (3.5 months after the vaccination and 3 months after the start of BFA feeding according to the scheme of the experiment), the immune response in the control and Group E48 to C. perfringens β-toxin remained at the initial level, while the response in Group E80 and Group E112 became higher under the influence of BFA feeding. Cows fed BFA saw a guaranteed improvement in non-specific resistance. The increase in serum lysozyme concentration in cows of Groups E was 1.01–2.91 mkg/mL vs. control (p < 0.001). TP, GLB, ALB/GLB vs. Groups C and E48 (p < 0.001); this stabilized and normalized while feeding Group E80 and E112 animals with BFA. They also had improved nitrogen, fat, mineral metabolism, as indicated by significant increase in ALB (p < 0.05), UREA (p < 0.01), CHOL (p < 0.01), and CHL (p < 0.01) vs. Groups C and E48. Consumption of BFA increased the amount of anti-oxidants in the blood (highest TAWSA values in Group E80 14.45 mg/g, p = 0.002). Serum TBA–AP/ CP ratio was directly related to TBA–AP (r = 0.87, p < 0.001), and decreased in Group E80. The milk productivity increased under the action of BFA; the average daily milk yield of the cows from the experimental groups for the period of the experiment (d0–d98) was 1.24–1.66 kg higher than that of the control. At the same time, Group E112 cows had a significant increase in milk yield (by 5.1%, p = 0.03 vs. Control). Thus, feeding BFA to dairy cows was found to improve resistance, prevent toxicoses and increase milk production of cattle, which can serve as an additional strategy for bioprotection of cattle against infection.

Relevance. The broad use of antimicrobials by agriculture and consumers motivation to buy antibiotic-free production form a basis to development of substitutes to antimicrobials. The goal of research was the analysis of antimicrobial resistance caused by veterinary antimicrobials administration to broilers, as well as the effect of metaprobiotic “Probiocid-Ultra” on antimicrobial resistance in dynamic.Methods. Three groups of broiler chickens were formed: I — control, who received the main diet, II — experimental, who received veterinary antibiotics enrofloxacin and colistin in addition to the diet of group I, III — experimental, who received the metaprobiotic “Probiocide-Ultra” in addition to the diet of group II. Gene expression analysis was performed using quantitative reverse transcription PCR. With inoculation to different media the antimicrobial resistance was examined with classical microbiological methods.Results. The dynamic of accumulation of antimicrobial resistance determinants caused by enrofloxacin and colistin administration to broilers was examined. Under the influence of enrofloxacin the increase in antimicrobial resistance to enrofloxacin itself, as well as to beta-lactams, tetracycline and colistin was observed. Under the influence of colistin the increase in antimicrobial resistance to colistin itself, as well as to enrofloxacin and beta-lactams was observed. The feed administration with metaprobiotic “Probiocid-Ultra” promoted noticeable decrease of the antimicrobial resistance genes amount, when analyzed with growth medium led to antimicrobial resistant enterobacteria vanished.