Onderstepoort Journal of Veterinary Research最新文献

Introduction: Metabolic syndrome (MetS) is a cluster of pathological conditions well described in humans but still investigated insufficiently in animals. A novel approach in its management is the utilisation of nutrients from natural sources. Recent studies suggested that phenolic compounds from pomegranate peel could be a promising dietary intervention for MetS. This study evaluated the potency of polyphenol-rich pomegranate peel extract (EPP) in mitigating some MetS components in an animal model.

Material and methods: Zucker diabetic fatty rats (with an fa/fa missense mutation in the Lepr leptin receptor gene) and their healthy counterparts (fa/+) as controls were fed a high-calorie diet to induce MetS and supplemented with EPP at two doses: 100 mg/kg body weight (b.w.) and 200 mg/kg b.w. The extract was administered for eight weeks. The rats' body weights were monitored twice per week, and blood samples were taken before EPP administration after four weeks and eight weeks of study. Echocardiography measurement was performed at the beginning and at the end of the study.

Results: The extract restrained the dynamic of weight gain. A cardioprotective effect of the highest dose of EPP supplementation was manifested in a relative decrease in heart rate and improved mid-fractional shortening, representing myocardial contractility. No improvement in fasting blood glucose or lipid profile was observed.

Conclusion: Pomegranate peel extract possesses beneficial health properties that could be useful in dietary intervention in MetS. However, its bioavailability still requires further investigation in clinical trials in humans and animals suffering from endocrine and metabolic disorders.

Introduction: Concentrations of polychlorinated dibenzo-p-dioxins and polychlorinated dibenzofurans (PCDD/Fs) and dioxin-like polychlorinated biphenyls (DL-PCBs) were investigated in six species of bivalve mollusc purchased on the Polish retail market. The risk to consumers was calculated as a percentage of the tolerable weekly intake (TWI) (2 pg World Health Organization toxic equivalent (WHO-TEQ) kg^-1 body weight (b.w.)).

Material and methods: Altogether 32 samples were analysed using an isotope dilution technique with high resolution gas chromatography coupled with high resolution mass spectrometry.

Results: Low levels of all analysed compounds were found. The range of PCDD/Fs was 0.08-0.37 pg WHO-TEQ g^-1 of wet weight (w.w.) and 0.04-0.41 pg WHO-TEQ g^-1 w.w. for DL-PCBs. The highest concentrations of all analysed compounds were found in Pacific oysters, at 0.30 pg WHO-TEQ g^-1 w.w. for the sum of PCDD/Fs and 0.19 pg WHO-TEQ g^-1 for the sum of DL-PCBs. These concentrations were 2-4 times higher than those detected in the other analysed mollusc species. Different species-dependent congener profiles were observed for PCDD/F concentrations, while PCB congener concentration profiles were species independent. The risk to consumers was assessed relating theoretical intakes of PCDD/Fs and DL-PCBs per 25, 50 and 100 g of consumption of molluscs per week to the TWI.

Conclusion: Taking into account the low consumption of molluscs in Poland and low concentrations of analysed compounds, neither adults nor children are likely to exceed the TWI by ingestion of food in this category.

Introduction: Alternative protein sources have recently been attracting growing interest as potential components of livestock nutrition. This study evaluated the effect on broiler health of replacing the soybean protein component of poultry feed with processed insect protein from farmed Hermetia illucens (HI) larvae.

Material and methods: A total of 384 male broiler chicks were divided into four diet groups (eight pens/treatment and 12 birds/pen) and reared to the 42^nd day of life (dol). Each treatment group received a starter diet until the 14^th dol, then a grower diet until the 35^th and finally a finisher diet until the 42^nd. The soybean meal in standard diets was replaced with full-fat HI larvae meal in the following amounts: 0% for the control group HI-0, 50% for group HI-50, 75% for group HI-75, and 100% for group HI-100. At 1 dol, chicks were vaccinated against Marek's disease, coccidiosis, Newcastle disease and infectious bronchitis and at 7 dol against avian metapneumovirus infections using live-attenuated vaccines. Blood and spleen samples were collected at three and six weeks of age and analysed using ELISA, flow cytometry, haematology and biochemistry.

Results: On the 42^nd dol, as the content of larvae meal in the chickens' diets increased, the birds' body weights decreased significantly. The substitution of the protein source had no effect on the haematological markers. In chicks that received larvae meal, there was a decrease in creatine kinase activity and phosphorus levels and an increase in calcium and uric acid levels in serum. Raising the proportion of full-fat HI larvae meal in the diet raised the percentage of T CD3⁺CD8a⁺ cells and lowered that of T CD3⁺CD4⁺ cells in both sample types. Chickens fed larvae meal had significantly lower post-vaccination anti-infectious bronchitis virus antibody titres.

Conclusion: The poorer production results and impaired health in experimental birds may indicate lower than 50% protein substitution with full-fat HI larvae meal to be optimal.

Introduction: Loss of pregnancy in mares is a major cause of economic and emotional impact for horse breeders. It can have many different infectious and noninfectious causes. The aim of this study was identification of the main viral causes of abortion in mares in Poland based on tissue samples from 180 aborted foetuses submitted for testing between 1999 and 2022.

Material and methods: Tissues of aborted foetuses collected from different horse studs throughout Poland were tested for the presence of equine herpesvirus types 1 and 4 (EHV-1/-4) and if negative, for equine arteritis virus (EAV). The examination was performed using a PCR/reverse transcriptase PCR (1999-2012) and a quantitative PCR (2013-2022).

Results: The cause of abortion was determined to be EHV-1 in 49.4% of cases (n = 89), whereas no EHV-4- or EAV-positive cases were found. The proportion of abortions due to EHV-1 differed between regions, with the highest percentage in the Lubelskie and Wielkopolskie provinces.

Conclusion: The results of the study indicate that EHV-1 is the most important viral infectious agent causing abortions in mares in Poland.

Introduction: Swine influenza A viruses (swIAVs) are characterised by high mutation rates and zoonotic and pandemic potential. In order to draw conclusions about virulence in swine and pathogenicity to humans, we examined the existence of molecular markers and accessory proteins, cross-reactivity with vaccine strains, and resistance to antiviral drugs in five strains of H1N1 swIAVs.

Material and methods: Amino acid (AA) sequences of five previously genetically characterised swIAVs were analysed in MEGA 7.0 software and the Influenza Research Database.

Results: Amino acid analysis revealed three virus strains with 590S/591R polymorphism and T271A substitution within basic polymerase 2 (PB2) AA chains, which cause enhanced virus replication in mammalian cells. The other two strains possessed D701N and R251K substitutions within PB2 and synthesised PB1-F2 protein, which are the factors of increased polymerase activity and virulence in swine. All strains synthesised PB1-N40, PA-N155, PA-N182, and PA-X proteins responsible for enhanced replication in mammalian cells and downregulation of the immune response of the host. Mutations detected within haemagglutinin antigenic sites imply the antigenic drift of the five analysed viruses in relation to the vaccine strains. All viruses show susceptibility to neuraminidase inhibitors and baloxavir marboxil, which is important in situations of incidental human infections.

Conclusion: The detection of virulence markers and accessory proteins in the analysed viruses suggests their higher propensity for replication in mammalian cells, increased virulence, and potential for transmission to humans, and implies compromised efficacy of influenza vaccines.

Introduction: The increasing resistance of bacteria to antibiotics has obliged the EU Member States to reduce by 50% the use of antibiotics in animal production by 2030. This study was undertaken with the aim to analyse the use of antibiotics in flocks of broiler turkeys reared in the Warmia and Mazury province in a two-year period.

Material and methods: From data from 238 production records of turkey flocks provided by the County Veterinary Inspectorates, the use of antibiotics (mg/kg) was analysed in turkey flocks reared in 2019-2021. The data provided the year of rearing, turkey sex and immunoprophylactic measures.

Results: A significant decrease in antimicrobial use was reported in the male turkey flocks in 2021 (157 mg/kg body weight) in comparison to 2020 (241 mg) and 2019 (299 mg). In both male and female turkeys, the use of antimicrobials gradually decreased from 2019 to 2021. Significantly lower antibiotic use was reported in turkey flocks using autogenous vaccines.

Conclusion: The positive trend shown in this study proves the possibility of meeting the EU recommendations for 50% reduction in the use of antibiotics in animal production by 2030. More emphasis should be placed on minimising the risk of infectious diseases requiring antibiotic therapy with welfare, biosecurity, immunomodulation and specific prophylaxis measures.

Introduction: The formation and function of the corpus luteum (CL) increase the likelihood of pregnancy and efficiently manage implantation. Apoptosis must occur at an appropriate time in the formation of the CL. This also affects its function. However, it is still unclear if the type of apoptosis affects the function.

Material and methods: We conducted morphological analysis of the CL collected on day 15 between the middle and late oestrous phases of Yorkshire pigs and mini-pigs, and measured the difference in hormone expression and apoptosis using an immunoassay method and messenger RNA level.

Results: The CL cells were more uniform in the Yorkshire pigs than in the mini-pigs, and the composition of the CL was also fuller. The expression of luteinising hormone was higher in the Yorkshire pigs. Apoptosis and the rate of action of matrix metalloproteinases (MMPs) were different between the two pig types. Expression of MMPs was higher in the Yorkshire pigs than in the mini-pigs. However, the expression of caspase 3 and 20alpha-hydroxysteroid dehydrogenase, a progesterone inhibitor, was potentiated in the mini-pigs.

Conclusion: Autophagy throughout the CL was more extensive in the Yorkshire pigs than in the mini-pigs, suggesting that autophagy and cell reorganisation by MMPs were highly correlated. The occurrence of autophagy in the formation and function of the CL may affect the action of hormones and expression of cell reconstitution factors.

Introduction: Because of the activities and effects they induce, hormones are prohibited for use for anabolic purposes in farm animals intended for slaughter, which is regulated in the European Union by relevant legal provisions. Therefore, there is an obligation to monitor residues of hormones in animals and food of animal origin to ensure consumer safety. A hormone banned but used formerly for fattening cattle, stanozolol, and its metabolite 16β-OH-stanozolol are synthetic compounds that belong to a large group of steroid hormones. This study investigates residues of these compounds in animal urine.

Material and methods: From 2006-2022, 2,995 livestock urine samples were tested for stanozolol residues in Poland as part of the National Residue Monitoring Programme. A liquid chromatography-tandem mass spectrometry method to determine stanozolol and 16β-OH-stanozolol in animal urine was developed and validated according to the required criteria. Urine sample analysis was based on enzymatic hydrolysis of hormones potentially present in it to the free form, extraction of them from the sample with a mixture of n-hexane and butyl alcohol, purification of an extract on an NH2 amine column and finally, instrumental detection.

Results: The apparent recovery and precision parameters of the developed method were in line with the established criteria, while its decision limits CCα and detection capabilities CCβ were lower than the recommended concentration for analytical purposes set at 2 μg L^-1 (valid until December 15, 2022; currently set as 0.5 μg L^-1).

Conclusion: All examined samples were compliant with the evaluation criteria.

Introduction: Due to the growing interest in the use of cannabinoids in supportive therapies, they are increasingly used together with anti-inflammatory drugs. Cannabinoids inhibit gastrointestinal motility, while steroidal and nonsteroidal anti-inflammatory drugs influence motility in other ways. The aim of the research was to study the interactions between cannabidiol (CBD) and these two classes of anti-inflammatory drugs in the context of gastrointestinal motility. Dexamethasone (DEX) was selected as a steroidal drug and diclofenac (DCF) as a nonsteroidal counterpart.

Material and methods: The experiments were performed on isolated rat colon strips in isometric conditions. The contractile response to acetylcholine (ACh) (1 μM) was measured with no substance applied as a control value and was measured after application of CBD (80 μM), DEX (100 μM), DCF (100 μM), or a combination of these substances.

Results: Cannabidiol strongly inhibited intestinal motility mediated by ACh application, DCF inhibited it non-significantly, while DEX intensified it. When CBD was co-administered with DEX, the combination inhibited intestinal motility non-significantly relative to the ACh-only control. Co-administration of CBD with DCF inhibited motility more than when these substances were administered separately.

Conclusion: Inhibition of the intestinal response to ACh is likely due to the synergistic effect of CBD and endogenous cannabinoids. Dexamethasone lessened the inhibitory effect of CBD, likely because of diminished availability of the arachidonic acid necessary for endogenous cannabinoid synthesis. However, diclofenac may increase endogenous cannabinoid synthesis, because of the greater availability of arachidonic acid caused by DCF blocking the cyclooxygenation pathway.

Introduction: The experiment was set to determine the effects of long-term (55-day) use of three commercial prebiotics including Saccharomyces cerevisiae-derived β-glucans and one including inulin on juvenile vimba (Vimba vimba) reared intensively under controlled conditions.

Material and methods: Six-month-old fish were fed commercial feed (Control group, n = 90), or the same feed supplemented with 0.02% Leiber Beta-S (BS group, n = 90), 0.20% Biolex MB40 (MB group, n = 90), 0.30% CeFi (CE group, n = 90) or 1.00% inulin Orafti GR (IN group, n = 90) for 55 days.

Results: In the BS group, the final growth parameters were significantly lower than in the Control group, while the feed conversion ratio was significantly higher. No significant differences were found between any other group and the Control group in the respective parameters. The respiratory burst activity of the head-kidney phagocytes was significantly lower in all fish groups fed the prebiotic-supplemented diets compared to the Control group. The proliferative response of the head-kidney lymphocytes stimulated by concanavalin A was lower in the BS group than in the Control group, while in other groups this response was not affected. No significant differences were found in histopathological analyses of the digestive tract, liver or pancreas.

Conclusion: The long-term supplementation of fish diets with prebiotics can negatively influence the growth, feed conversion, nonspecific cellular resistance and proliferative activity of the T lymphocytes of vimba juveniles.