Numerical and behavioral responses of waterfowl to the invasive American mink: A conservation paradox

A behavioral response is usually the first adaptation of animals to environmental changes such as the introduction of an alien invasive species, and it seems to be the most important factor in reducing the negative impact of new predators on naive prey. This study examined changes in the abundance and behavior of breeding coots (Fulica atra) and great crested grebes (Podiceps cristatus) in response to invasion of the Mazurian Lakeland (NE Poland) by American mink (Neovison vison), first recorded here in 1984. Feral mink densities varied from 1.0 to 14.6 individuals per 10 km of shoreline. Mink were responsible for the losses of 17–58% of experimental clutches (artificial nests containing chicken eggs) that were deployed. Mink destroyed more experimental clutches than other predators; the effects of mink predation were similar in reeds and on the bank. Radio-tracking showed that mink avoided lake banks near human settlements. Mink have markedly affected the breeding distribution of both species and caused a greater than 20-fold decline in coot numbers. For coots and grebes breeding distribution and nesting success were positively associated with built-up areas along lake shores and also with whether the birds were breeding in colonies. Increased brood survival of coots and grebes near human settlements is a paradox in the sense that a man-made habitat change has provided refuge from an alien predator.     

Does meatiness of pigs depend on the level of gastro-intestinal parasites infection?

The aim of the present paper was to determine an influence of the presence and a level of intestine parasites infection on the quality of pork carcass expressed by the content of meat in carcass (meatiness) in pigs. The experimental part of the study was conducted on pigs farm produced in a closed cycle. The population in the study included 120 fattening pigs maintained in two keeping systems: group I--60 individuals kept on slatted floor, and group II--60 individuals kept on deep litter. All the experimental animals were treated in the same manner. The analysed fatteners were slaughtered in Meat Processing Plant when their body mass reached 110 kg, and the post-slaughter assessment was conducted according to the EUROP classification of pigs carcass using the Ultra-Fom 300 device. The study concerning the internal parasites were conducted basing on coproscopic quantitative McMaster method. As a results, the eggs of three nematode taxa were isolated and identified: Oesophagostomum spp., Ascaris suum and Strongyloides ransomi. Overall prevalence of infection of fatteners kept on litter was lower (25%±11.2) as compared to those kept on slatted floor (38.3%±12.6), however the differences were not statistically significant (χ(2)=2.465; df=1; P=0.116). The mean value of meatiness for pigs free from parasites was 53.68, while in the case of infected pigs the meatiness was statistically lower and was 52.12 (t=2.35; P=0.02). The analysed pigs were classified into three categories and conducted analysis of an influence of parasites on meatiness demonstrate the relationship that is statistically significant. The analysis of correlation between meatiness and an average number of helminth eggs also demonstrated the negative, statistically significant, relationship (F=5.52; P=0.020), i.e. in fatteners with higher EPG value the meatiness was lower.     

The factors affecting the distribution of babesiosis in dogs in Poland

The aim of this paper was to determine the factors affecting the development of canine babesiosis in Poland. The studies included 800 animals from 16 polish voivodeships-districts (50 from each voivodeship) with suspected piroplasmosis. Hematological and molecular tests confirmed infections in 158 animals. Analysis of the genetic material using the Real-Time Sybr Green HRM technique showed that 96 dogs were infected with Babesia canis 18S RNA-A and 62 with B. canis 18S RNA-B. It was observed that the disease occurs more often in eastern Poland (OR: 8.91; CI: 5.7-13.8), in males (OR: 1.04; CI: 0.7-1.5) and especially in rural areas (OR: 1.7; CI: 1.2-2.4). More prone to infection were pure-bred dogs (OR: 2.24; CI: 1.6-3.2), young animals under 1 year old (OR: 0.73; CI: 0.4-1.5), animals that had suffered from babesiosis in the past (OR: 17.9; CI: 10.9-29.2) and those that had not received preventive measures against ectoparasites (OR: 0.32; CI: 0.2-0.5). Knowledge of the factors facilitating the development of canine babesiosis helps to understand the causal connection between the dogs' exposure to the pathogen and the development of the disease and to limit the occurrence of the infection in these animals, to diagnose it early and to start proper treatment before serious complications develop.     

Artificial reproduction of wild and cultured barbel (Barbus barbus, Cyprinidae) under controlled conditions

The aim of this work was to compare the effects of controlled reproduction of cultured and wild common barbel, Barbus barbus (L.). Preparations containing different GnRH analogues and dopamine receptor antagonists (Ovopel, Ovaprim) as well as human chorionic gonadotropin (hCG) (in the case of cultured fish) were applied and their influence on ovulation, spermiation and quality of gametes obtained was determined. No differences in the qualitative or quantitative parameters of semen were found between fish stimulated with different hormonal preparations and those not receiving hormonal stimulation. The high suitability of Ovaprim for ovulation induction in (cultured and wild) barbel was confirmed. The highest synchronisation of ovulation was obtained after the application of Ovopel (18 ± 3 h), but the best results of controlled reproduction (expressed as the percentage of ovulations and survival of embryos) were obtained by applying Ovaprim (83.2 ± 4.1). A significantly higher percentage of ovulation was obtained in cultured fish (80-90%) than in wild fish (< 25%).     

Effect of cadmium injected in ovo on hatching results and the activity of plasma hydrolytic enzymes in newly hatched chicks

The aim of the study was to determine the toxicity of cadmium ions in chick embryos, using plasma hydrolytic enzyme as its biomarker. Hatching eggs (n = 300) from Ross 308 broilers were incubated under standard conditions. On day 4 of incubation, 50 μl of saline solution, containing Cd ions at a concentration from 0 (control group) to 24 μg, was injected in ovo into the egg albumen. The results indicate that the administration of cadmium at doses exceeding 1 μg/egg caused a gradual decrease in hatchability, with an LD50 of 3.9 μg/egg. The greatest differences between the groups in the enzymatic activities studied were found for N-acetyl-β-D-glucosaminidase (NAG), β-D-mannosidase (β-MAN) and arylsulphatase (ARYL). Compared to the control group, in the blood serum of chicks from the groups receiving 3, 6 and 12 μg Cd/egg the NAG activity increased by 79, 108 and 54% and β-MAN activity by 33, 119 and 108%, respectively. Exposure to cadmium at a dose of 1 to 6 μg per egg caused an about 60% increase in ARYL activity while a dose of 12 μg decreased the activity by about 35% below the level observed in the control group. These findings show that cadmium has a similar toxicity mechanism in mammals and birds, which opens the possibility of using NAG activity as a biomarker of the cytotoxic effect of cadmium in birds.     

Tetrodotoxin- and resiniferatoxin-induced changes in paracervical ganglion ChAT- and nNOS-IR neurons supplying the urinary bladder in female pigs

The aim of the present study was to establish the effect of intravesical administration of resiniferatoxin (RTX) and tetrodotoxin (TTX) on the chemical coding of paracervical ganglion (PCG) neurons supplying the urinary bladder in the pig. In order to identify the PCG neurons innervating the bladder, retrograde tracer Fast Blue was injected into the bladder wall prior to intravesical RTX or TTX administration. Consequent application of immunocytochemical methods revealed that in the control group 76.82% of Fast Blue positive PCG neurons contain nitric oxide synthetase (nNOS), and 66.92% contain acetylcholine transferase (ChAT). Intravesical infusion of RTX resulted in a reduction of the nNOS-IR neurons to 57.74% and ChAT-IR to 57.05%. Alternative administration of TTX induced an increase of nNOS-IR neurons up to 79.29% and a reduction of the ChAT-IR population down to 3.73% of the Fast Blue positive PCG cells. Our data show that both neurotoxins affect the chemical coding of PCG cells supplying the porcine urinary bladder, but the effects of their action are different. Moreover, these results shed light on the possible involvement of NO-ergic and cholinergic neurons in the mechanisms of therapeutic action exerted by RTX and TTX in curing the overactive bladder disorder.     

Effect of maternal antibodies and pig age on the antibody response after vaccination against Glässers disease

The influence of age and maternal antibodies on the development and duration of postvaccinal antibody response against Glässer’s disease were investigated. Pigs born to immune (MDA-positive) and non-immune (MDA-negative) sows were vaccinated with inactivated vaccine. Vaccination was done according to three different protocols: at 1 and 4, at 2 and 5 or at 4 and 7 weeks of age. There were also two control groups for MDA-negative and MDA-positive pigs. The level of Haemophilus parasuis (Hps) specific antibodies were determined using commercial ELISA test. No serological responses were seen in any of the groups after the first vaccination. Maternally derived antibodies (MDA) against Hps were above the positive level until approximately 3 weeks of life in MDA-positive pigs. In those pigs the strongest postvaccinal humoral response was observed in piglets vaccinated at 4 and 7 weeks of age. In the remaining MDA-positive piglets only slight seroconversion was noted but levels of antibodies never exceeded values considered as positive. All MDA-negative pigs produced Hps-specific antibodies after the second vaccination. The results of the present study indicated that MDA may alter the development and duration of active postvaccinal antibody response. Age of pigs at the moment of vaccination was not associated with the significant differences in the magnitude of antibody response, however influenced the kinetics of decline of Hps-specific antibodies.     

Fungistatic activity of bicyclo[4.3.0]-γ-lactones

Five optically active and sixteen racemic lactones (nine of them new) of bicyclo[4.3.0]nonane structure were synthesized. IC(50) values for the following phytopathogens were determined: Aspergillus ochraceus AM 456, Fusarium culmorum AM 282, Fusarium oxysporum AM 13, Fusarium tricinctum AM 16. Effect of compound structures, especially stereogenic centers, on fungistatic activity has been discussed. The highest fungistatic activity was observed for trans-7,8-dibromo-cis-3-oxabicyclo[4.3.0]nonan-2-one (3c), IC(50) = 30.1 μg/mL (0.10 μM/mL), and cis-7,8-epoxy-cis-3-oxabicyclo[4.3.0]nonan-2-one (3b), IC(50) = 72.2 μg/mL (0.47 μM/mL), toward F. oxysporum AM 13.