Research Note: Oxidative stress and immune response following the administration of live attenuated Mycoplasma gallisepticum vaccination in backyard chicken

In the present study, we investigated a possible relationship between the immune response and the oxidative stress (OS) state trend in a group of 12 chickens after intraocular administration of an attenuated Mycoplasma gallisepticum (MG) vaccine. Blood samples were collected at the vaccination time (T0), after 14 (T1) and 21 d (T2). White blood cell count (WBC), differential leucocyte count, and anti-MG antibodies titer (S/P) were studied as immune response indexes. As plasmatic OS biomarkers levels, we considered malondialdehyde (MDA), nitric oxide (NO), superoxide dismutase (SOD), reactive oxygen metabolites derived compounds (d-ROMs), the ferric reducing ability of plasma (FRAP), and superoxide anion (O₂^-). After antigenic stimulation, it was observed a significant decrease in monocythemia and a significant increase in thrombocythemia, S/P, MDA, and SOD. Furthermore, subjects with high d-ROMs levels at T0 tended to develop higher cellular mobilization with increases in WBC and lymphocytes accompanied by lower antibody release. It was also observed that the antioxidant components FRAP and SOD were moderately positively correlated to the entity of antibody response.

The effects of nanoplastics on adipose stromal cells from swine tissues

Plastic is one of the main sources of marine and terrestrial pollution. This material can fragment into micro- (<-5 mm) and nanoplastics (NPs) (<100 nm) following degradation. Animals are exposed to these particles by ingesting contaminated food, respiration or filtration, and transdermally. In organisms, NPs can cross biological membranes, and cause oxidative stress, cell damage, apoptosis, and endocrine interference. We previously demonstrated that polystyrene - NPs interfered with ovarian cell functions. Since reproduction involves a high energy expenditure and a crucial role is played by adipose tissue, the aim of the present study was to evaluate the effects of NPs on primary adipose stromal cells (ASCs) isolated from swine adipose tissues. In particular, the effects on cell viability, proliferation, metabolic activity, inflammatory process mediators and oxidative stress markers were assessed. The obtained results did not reveal a significant variation in cell proliferation, metabolic activity was increased (P < 0.01) but only at the lowest concentration, while viability showed a significant decrease after prolonged exposure to NPs (P < 0.01). TNF-α was increased (P < 0.05), while PAI-1 was inhibited (P < 0.001). Redox status was significantly modified; in particular, the production of O₂^-_, H₂O₂ and NO was stimulated (P < 0.05), the non-enzymatic antioxidant power was reduced (P < 0.05) while catalase activity was significantly (P < 0.01) increased.

Nanoplastics impair in vitro swine granulosa cell functions

Soil, water, and air pollution by plastic represents an issue of great concern since the particles produced by degradation of plastic materials can be ingested by animals and humans, with still uncertain health consequences. As a contribution on this crucial subject, the present work reports an investigation on the in vitro effects of different concentrations of polystyrene nanoplastics (5, 25, and 75 µg/mL) on swine granulosa cells, a model of endocrine reproductive cells. In particular, cell growth (BrDU incorporation and ATP production), steroidogenesis (17-β estradiol and progesterone secretion) and redox status (superoxide and nitric oxide production, enzymatic and non-enzymatic scavenging activity) were studied. Nanoplastics, at the highest concentration, stimulated cell proliferation (P < 0.05), while cell viability resulted unaffected. Steroidogenesis was disrupted (P < 0.05). Both enzymatic and non-enzymatic scavenging activity were increased after exposure at the highest nanoplastic dose (P < 0.05, P < 0.001). Nitric oxide secretion was increased by 25 and 75 µg/mL (P < 0.05) while superoxide generation was stimulated (P < 0.001) only by the highest concentration tested. Taken together, main features of cultured swine granulosa cells resulted affected by exposure to nanoplastics. These results raise concerns since environment nanoplastic contamination can represents a serious threat to animal and human health.

Evaluation of Oxidative Stress in Blood of Domestic Chickens and Eurasian Magpies (Pica pica)

A physiological equilibrium exists between pro- and antioxidant factors. When the oxidant factors exceed the capacity of their removal or inactivation, oxidative stress (OS) occurs. The OS levels were assayed in plasma obtained from 2 bird species. Blood samples were collected from 20 healthy domestic chicken hens, 10 living in an intensive farming environment and 10 free-range, and from 18 healthy Eurasian magpies (Pica pica; 7 females and 11 males, with an estimated age of >1 year of age). For OS biomarker assessment, the determinable reactive oxygen metabolites (d-ROMs) were measured, and the plasmatic antioxidant test (PAT) was performed; the OS index (OSI) was then calculated (d-ROMs/PAT × 1000) as a parameter of overall oxidative stress. Moreover, lipid peroxidation was assessed by measuring plasmatic malondialdehyde (MDA) levels. A hematological evaluation was also performed on each bird with a hemocytometer, on which a blood sample was placed to obtain both a total and differential white blood cell (WBC) count. In hens, OSI and MDA levels were significantly higher (P = .04, and P = .004) in subjects from intensive farming (14.7 ± 7.1 and 27.2 ± 10.4 nmol/mL) than in those bred in rural conditions (5.6 ± 10.3 and 8.2 ± 13.3 nmol/mL). In magpies, a positive correlation between the total WBC count and OS was found, and both d-ROMs and OSI were significantly higher (P = .03) in subjects with a total WBC count greater than the median value (20.4 × 10³ cells/µL) with respect to those with a total WBC count less than the median value. The results generated from this study indicate that higher OS levels occurred in hens bred in an intensive indoor farm environment compared with outdoor free-range conditions. Possibly the higher OS levels could be related to the higher stocking density and dust levels found in the indoor facility. Additionally, the correlation between OS biomarker levels in magpies and total WBC count suggests that OS level is influenced by immune response, in agreement with previous studies. Collectively, present data seem to be promising for the application of OS measurement in avian medicine for health and animal welfare monitoring.

Lead Levels in Wild Boar Meat Sauce (Ragù) Sold on the Italian Market

Game meat is endowed with excellent nutritional value, but it may also be a possible source of harmful substances, such as mycotoxins and heavy metals. In particular, several studies showed that lead fragments from hunting ammunition are able to represent a residual contaminant in the meat of wild boars or deer, representing a possible source of lead absorption. Even though wild boar meat consumption in Italy is rather limited, this meat could also be present in very popular Italian recipes, such as the typical meat sauce called ragù. We evaluated the lead levels in 48 samples (three different batches for each of the 16 brands) of ready-to-eat wild boar meat ragù sold on the Italian market in food stores and online distribution with the inductively coupled plasma-mass spectrometry (ICP-MS) technique. A high variability was found in the lead levels detected in the samples, with a median lead level of 0.10 mg/kg (0.01–18.3 mg/kg) and some of the samples showing very high lead concentrations. Since no intake level of lead is considered completely safe, and maximum levels for game meat have so far not been established, a greater attention on the risks to consumers’ health related to the presence of this heavy metal in game meat is recommended.

Heavy Metal Assessment in Feathers of Eurasian Magpies (Pica pica): A Possible Strategy for Monitoring Environmental Contamination?

In the present study, the Eurasian magpie (Pica pica), was evaluated as a possible bioindicator of environmental pollution by heavy metals (HMs). Levels of Ni, Pb, Cd, and Hg in feathers of 64 magpies (31 males and 33 females) were measured by ICP-MS technique. Plasmatic biomarkers of oxidative stress (OS) were also assessed. The birds were captured in the province of Parma (Italy), in different capture sites within 1 km from urban area (UZ), and farther than 5 km from urban area (RZ). Median HM levels were 0.68 mg/kg (0.18–2.27), 2.80 mg/kg (0.41–17.7), <limit of detection (LOD) mg/kg (<LOD–0.25), 3.90 mg/kg (1.35–85.9) for Ni, Pb, Cd and Hg, respectively. No significant differences in HM levels were found according to sex, while Ni and Pb were significantly higher in adult compared to young birds (p = 0.047, p = 0.004). Conversely, Cd and Hg levels in young magpies resulted higher than those of adults (p = 0.001 and p = 0.004). No correlation was found between OS biomarkers and HM levels. No differences were found in HM levels according to capture area, except for Hg level, which resulted higher in magpies of RZ (4.05 mg/kg (1.35–12.7)) compared to UZ (2.99 mg/kg (1.54–85.9)). Further experiments are needed to establish whether magpie feathers could represent a suitable non-invasive tool for biomonitoring HMs in the environment.

Ochratoxin A Levels in Tissues of Wild Boars (Sus scrofa) from Northern Italy

Ochratoxin A (OTA) is a mycotoxin produced by Aspergillus and Penicillium, capable of contaminating several foodstuffs. OTA damages primarily the kidneys, and is suspected to be a carcinogenic substance, thus maximum levels for OTA in foodstuffs have been established in the EU. Italian Ministry of Health suggested a maximum level of 1 μg/kg OTA in pork meat and derived products. In this study, OTA concentrations in liver, kidney, and muscle of 64 wild boars (Sus scrofa) killed in two areas (area A and B) of Parma province (northern Italy), characterized by different habitat types, were assessed by HPLC-FLD technique. OTA was detected in 54% liver, 52% kidney, and 16% muscle samples. OTA levels were significantly higher in liver and kidney compared with muscle, and were above 1 μg/kg in 19 liver, 17 kidney, and 4 muscle samples. OTA levels in wild boars from area A resulted significantly higher with respect to those from area B, suggesting an environmental influence on OTA contamination in wild boars. This study seems to confirm that wild boar meat is a potential source of OTA, thus monitoring the presence of this mycotoxin in game meat might be recommended to prevent risks for human health.

Wild Micromammals as Bioindicators of Antibiotic Resistance in Ecopathology in Northern Italy

Antimicrobial resistance (AMR) is an increasing threat to human health and an important issue also in the natural environment. For this study, an ecopathological approach was applied to the monitoring of the antimicrobial resistance in the province of Parma, Northern Italy. Fourteen monitoring sites and seventy-four faecal samples from four species of wild micromammals (Apodemus sylvaticus, Microtus savii, Mus domesticus and Suncus etruscus) were collected. Samples were subjected to bacteriological examination and antimicrobial susceptibility testing. Antibiotics belonging to 13 different antibiotic classes were tested. Collected data showed a prevalence of multi-drug resistant (MDR) strains of 55.13% and significant differences in the prevalence of MDR strains among the different micromammal species, while sex, age and anthropization level did not significantly affected MDR strains prevalence. Moreover, a high prevalence of bacterial strains resistant to colistin (95%), gentamicin (87%) and amikacin (83%) was observed. To our knowledge, this is the first report on antibiotic resistance in wild micromammals in the province of Parma.

Toxoplasma gondii in the Eurasian kestrel (Falco tinnunculus) in northern Italy

Background

Identifying factors that sustain parasite transmission is important for understanding their spread and emergence, including how changes in biodiversity may affect parasite prevalence and spread. Toxoplasma gondii is a protozoan parasite infecting humans and animals. Birds can acquire T. gondii infection through ingestion either of oocysts from the ground or of tissue cysts present in infected prey and are therefore suitable indicators of the presence of T. gondii in the natural environment.

Methods

The aim of the study included the evaluation of T. gondii seroprevalence in clinically healthy Eurasian kestrels (Falco tinnunculus) using a modified agglutination test. Birds were captured in a small area of Parma (northern Italy) for two consecutive years (2016–2017), sex and age determined and serological study carried out. Food sources for the birds were also evaluated, in particular rodent and grasshopper population estimates in the study area. The biomass of rodents and grasshoppers per hectare was estimated in order to directly compare food availability. Statistical analyses were performed in order to evaluate factors influencing the probability of kestrels being T. gondii-seropositive using R 3.4.4 fitting linear mixed-effect models with the ‘glmer’ function of the package lme4, ‘lsmean’ in package lsmean for pair-wise post-hoc comparisons using differences of least square means (DLSM) and the ‘betareg’ function of the package betareg for beta regression.

Results

Seroprevalence for T. gondii was 33.3% (49/147) in 2016, while in 2017 seroprevalence decreased to 14.3% (13/91). An increase in the probability of kestrels being T. gondii-seropositive was associated with a higher rodent biomass in the environment, suggesting a positive feedback of the biotic factors driving infection risk.

Conclusions

These results underline the need for multidisciplinary studies aimed at better understanding pathogen-host relationships and for predictions in disease ecology.

The prevalence of Pseudomonas aeruginosa and multidrug resistant Pseudomonas aeruginosa in healthy captive ophidian

Background

Snakes are globally considered as pet animals, and millions of ophidians are bred in captivity. Pseudomonas aeruginosa is a ubiquitous Gram-negative bacterium that can act as an opportunistic pathogen of man and animals and is frequently present in the oral and cloacal microbiota of healthy ophidians. It can cause severe clinical diseases and often shows antibiotic resistance. The aim of this study was to evaluate the prevalence and antibiotic resistance profiles of P. aeruginosa isolated from the cloacal microbiota of a large population sample of healthy captive ophidians and to evaluate the statistical associations with farming conditions.

Methods

A total of 419 cloacal swabs were collected from snakes belonging to the Boidae (n = 45), Colubridae (n = 48) and Pythonidae (n = 326) families and inoculated onto complete culture media. Food, water and bedding samples were also analyzed. The antimicrobial susceptibility of P. aeruginosa isolates was evaluated through the Kirby-Bauer agar diffusion test. Statistical analyses were performed with the chi-square test.

Results

The prevalence of P. aeruginosa was 59.9%, and 35.5% of these strains were multidrug resistant (MDR). The prevalence of MDR P. aeruginosa was significantly higher in adult samples than in young samples, and widespread resistance to Cephalosporins, Polymyxins and Sulfonamides was observed. Statistically significant differences in the prevalence of P. aeruginosa were observed depending on the farm size and snake family. Feeding thawed prey was associated with a higher P. aeruginosa and MDR P. aeruginosa prevalence. Moreover, snakes fed home-raised prey had a significantly higher MDR P. aeruginosa prevalence than snakes fed commercially available feed. Less frequent terrarium cleaning was associated with a higher MDR P. aeruginosa prevalence. On the other hand, snake reproductive status was not significantly associated with P. aeruginosa or MDR P. aeruginosa prevalence. All food, water and bedding samples were negative for P. aeruginosa presence.

Discussion

The overall P. aeruginosa prevalence found in this study was lower than that found by other authors, but a high proportion of the isolates were MDR. This study highlighted the presence of constitutive (such as age and taxonomic family) and managerial (farm size, cleaning cycle frequency and food type) factors associated with P. aeruginosa and/or MDR P. aeruginosa prevalence. Good breeding management and proper antibiotic treatment of P. aeruginosa infections could help reduce the presence of P. aeruginosa and MDR P. aeruginosa in the gut microbiota of snakes and consequently reduce the risk to public health.