Effects of florfenicol feeding on diversity and composition of the intestinal microbiota of channel catfish (Ictalurus punctatus)

Intestinal microbiota contributes health of living organisms. Florfenicol is an approved antimicrobial (AM) prescribed for several bacterial fish diseases. The present study investigated the extent to which florfenicol modulates intestinal microbial populations of channel catfish (Ictalurus punctatus). Florfenicol was administered orally to catfish at a standard therapeutic dose (10–15 mg/kg of body weight for 10 days), and the intestinal contents were collected and the 16S rRNA was subjected to Illumina sequencing. Alpha diversity analysis indicated that florfenicol significantly decreased microbiota richness and diversity. Beta diversity reflected a clear separation had occurred between the florfenicol‐fed and control groups. Results indicated a significant increase in the abundance of phylum Proteobacteria (98.97% vs. 79.35% of the population) and decrease in phyla Firmicutes and Bacteroidetes (0.72% and 0.29% vs. 18.04% and 2.53%, respectively) in the florfenicol‐fed fish in comparison with the control fish. At the genus level, unclassified Enterobacteriaceae and Escherichia populations increased in the florfenicol group. In contrast, Plesiomonas, Aeromonas, Lactococcus, Clostridium sensu stricto, Romboutsia, Klebsiella, Turicibacter and Lactobacillus decreased in florfenicol‐fed fish in comparison with the control fish, indicating that intestinal microbiota of catfish was substantially modulated by florfenicol administration. Knowledge of changes in gut microbiota during medicated feed administration is important to improve fish performance and disease management and could enable the development of alternative therapeutic strategies.     

Antioxidative role of selenium against the toxic effect of heavy metals (Cd<Superscript>+2</Superscript>, Cr<Superscript>+3</Superscript>) on liver of rainbow trout (<Emphasis Type="Italic">Oncorhynchus mykiss</Emphasis> Walbaum 1792)

The main purpose of this study is to discuss the effect of Cd⁺², Cr⁺³ and Se metals on biochemical parameters in liver tissue of Oncorhynchus mykiss. The rainbow trout were exposed to heavy metal stress (Cd⁺², Cr⁺³) at 2 ppm dosage. The present study was undertaken to determine the protective effect of selenium treatment at the same dosage (2 ppm) on some biochemical parameters. The activity of catalase (CAT), glutathione peroxidase (GSH-Px), superoxide dismutase (SOD) and the changes in levels of malondialdehyde (MDA) from biochemical parameters were determined in liver tissue of the fish groups exposed to heavy metals, especially for the selenium-applied groups. Results of this study showed that the activities of CAT, GSH-Px and SOD in the tissues of fish exposed to the stress of Cd⁺² and Cr⁺³ were significantly lower than the control groups (P < 0.05). Meanwhile, the closer values to the control groups were obtained in selenium-added groups (Cr⁺³ + Se⁺⁴, Cd⁺² + Se⁺⁴). For the level of MDA, the last production of lipid peroxidation showed increases (P < 0.05) in the groups exposed to the metal stress, whereas significant decreases were obtained in selenium-applied groups. The result of the statistical evaluation showed that the negative effects occurring in the biochemical parameters of the applied groups exposed to the toxicity of heavy metal were significantly eliminated (P < 0.05) as a result of selenium treatment.     

Comparison of satellite images with different spatial resolutions to estimate stand structural diversity in urban forests

The structural diversity in urban forests is highly important to protect biodiversity. In particular, fruit trees and bush species, cavity-bearing trees and coarse, woody debris provide habitats for animals to feed, nest and hide.Improper silvicultural practices, intensive recreational use and illegal harvesting lead to a decline in the structural diversity in forests within larger metropolitan cities. It is important to monitor the structural diversity at definite time intervals using effective technologies with a view to instituting the necessary conservation measures. The use of satellite images seems to be appropriate to this end. Here we aimed to identify the associations between the textural features derived from the satellite images with different spatial resolutions and the structural diversity indices in urban forest stands(Shannon–Wiener index, complexity index, dominance index and density of wildlife trees).Rapid Eye images with a spatial resolution of 5 m 9 5 m,ASTER images with a spatial resolution of 15 m 9 15 m and Landsat-8 ETM satellite images with a spatial resolution of 30 m 9 30 m were used in this study. The firstorder(standard deviation of gray levels) and second order(GLCM entropy, GLCM contrast and GLCM correlation)textural features were calculated from the satellite images.When associations between textural features in the images and the structural diversity indices were assessed using the Pearson correlation coefficient, very high associations were found between the image textural features and the diversity indices. The highest association was found between the standard deviation of gray levels(SDGLRAP) derived from RVIRAPof Rapid Eye image and the Shannon–Wiener index(Hh) calculated on the basis of tree height(R2= 0.64). The findings revealed that Rapid Eye satellite images with a spatial resolution of 5 m 9 5 m are most suitable for estimating the structural diversity in urban forests.     

Bioequivalence Study of Two Long-acting Oxytetracycline Formulations in Sheep

Two commercially available long-acting oxytetracycline hydrochloride formulations (Primamycin LA (Pfizer) and Terralent 20% LA (İ.E. Ulagay)) were administered by the intramuscular route to 20 clinically healthy sheep at a dose of 20 mg/kg. The study was performed in a two-period crossover design. Plasma samples were analysed by high-pressure liquid chromatography. The mean maximum concentrations (C _max) was 8.00 ± 2.05 μg/mland 8.61 ± 1.42 μg/ml, respectively. The mean area under the concentration time curve (AUC) values were 154.95 ± 50.37(μg h)/ml and 161.70 ± 47.02(μg h)/ml, respectively. The 90%confidence intervals for the ratio of C _max and AUC values for the test and reference product are with in the interval 70−143% for C _max and interval 80-−125% for AUC proposed by EMEA. It was concluded that Primamycin LA and Terralent 20% LA formulations are bioequivalent in their rate and extent of drug absorbtion. Ozdemir N. and Yıldırım, M., 2006. Bioequivalence study of two long-acting oxytetracycline formulations in sheep. Veterinary Research Communications, 30(8), 929–934     

Determination and transferability of plasmid‐mediated antibiotic resistance genes of the bacteria isolated from rainbow trout

Antibiotic resistance and the presence of resistance genes (ARGs) were investigated in the bacteria isolated from rainbow trout (Oncorhynchus mykiss) from different trout farms located in Turkey. The most frequent types of antibiotic resistance were towards β‐lactams (cephalothin [70% of bacterial isolates], amoxicillin [63%], ampicillin [62%], ticarcillin [56%], aztreonam [51%]), macrolide [erythromycin, 68%] and sulphonamide [sulphamethoxazole, 51%]. Of bacterial isolates, 51% were multiple drug resistant (MDR), while 35% of the isolates were extensively drug resistant (XDR). None of isolates were pandrug resistant (PDR). The most common ARGs were ampC (36%) and sul1 (24%). The class 1 integron gene cassette was detected in 51% of the bacteria. There was a strong positive correlation between the antibiotic resistance rate and the presence of ARGs (r² = .932). Gene encodes bla_CTX‐M1, one of the extended spectrum beta‐lactamase enzymes, was first described in Aeromonas caviae, Photobacterium damselae, Pseudomonas luteola and Burkholderia cepacia. It was determined that 35% of the bacteria harboured at least one plasmid. Plasmid‐mediated ARGs were identified to be tetracyclines (tetA, tetB, tetC, tetD), sulphonamides (sul1, sul3) and β lactams (ampC, bla_pse). Thus, results suggest that ARG contamination situation deliberates resistance to tetracycline, aminoglycoside, chloramphenicol and sulphonamide. Therefore, the presence and activity of ARGs in fish and in environmental bacteria may play an important role in the spread of resistance genes among bacteria by transposition or integron gene cassettes.     

The distribution of the coronary arteries in the Angora rabbit

The aim of this study was to determine the origin, course, termination and anastomosing of the coronary arteries in Angora rabbits. Eight adult healthy male Angora rabbits were used. Coloured latex was injected into the ascending aorta. A. coronaria sinistra of the Angora rabbit had larger diameter than a. coronaria dextra. It was divided into r. proximalis atrii sinistri, r. interventricularis paraconalis and r. circumflexus sinister in six Angora rabbits as well as r. septi interventricularis in two. R. septi interventricularis that stem directly from a. coronaria sinistra in two animals and from r. interventricularis paraconalis in six was a principal vessel responsible for the septum interventriculare. R. marginis ventricularis sinistri originating from r. circumflexus sinister was the most prominent artery on the auricular surface of the heart. R. interventricularis subsinuosus was not detected in Angora rabbits examined. A. coronaria dextra, crossing the sulcus coronarius immediately after its origin, ran obliquely in direction of the sulcus interventricularis subsinuosus to supply the right portion of the heart. The ventricular and septal branches of a. coronaria sinistra and a. coronaria dextra ran subepicardially at the beginning then intramyocardially and mostly parallel to the muscle fibres as surrounded by a thin adipose tissue. Their atrial branches were seen continuously to run subepicardially.     

PHYSICOCHEMICAL CHARACTERIZATION OF HAZELNUT HUSK RESIDUES WITH DIFFERENT DECOMPOSITION DEGREES FOR SOILLESS GROWING MEDIA PREPARATION

In this study, the main physical, physiochemical, and chemical properties of hazelnut husk have been determined for the suitability as a container growing medium. Four substrates were prepared based upon decomposition degree: raw (H₁), medium decomposed (H₂, H₃), and strongly decomposed hazelnut husk samples (H₄), to determine the optimum growing medium parameters. Particle size was the key parameter to determine the physical properties, which was decreased with the increasing decomposition degrees. The main physical parameters were in the ranges for the ideal growing medium characteristics for H₄. Except for raw material (H₁), chemical characteristics such as pH, electrical conductivity (EC), carbon (C)/nitrogen (N), and nutrients were within acceptable ranges. The results indicated that hazelnut husk could be an alternative growing media component for containerized crops, if optimum particle size within the range of 0-2mm is obtained, for both aeration and water holding requirements.     

Dietary vitamin E (alpha-tocopherol acetate) and selenium supplementation from different sources: performance, ascites-related variables and antioxidant status in broilers reared at low and optimum temperatures

1. This study compared the effect of dietary supplementation with organic or inorganic selenium (Se) sources plus control amounts or large amounts of vitamin E (alpha-tocopherol acetate) in broilers raised at control (20 to 24 degrees C) or low (14.5 to 16.8 degrees C) temperatures after 2 weeks of age. 2. The following dietary treatments were used from one day old. Diet 1, the control diet, comprised a commercial diet containing 0.15 mg/kg inorganic Se and 50 mg vitamin E/kg feed. Diet 2 was the same as diet 1, supplemented with 0.15 mg/kg inorganic Se. Diet 3 was the same as diet 2 but was supplemented with 200 mg/kg vitamin E. Diet 4 was the same as diet 1, but inorganic Se was replaced with 0.30 mg/kg organic Se. Diet 5 was the same as diet 4, supplemented with 200 mg/kg vitamin E. 3. Low temperature reduced the growth rate of broilers; however, at 6 weeks, there were no differences in the body weights of birds fed on organic Se supplemented diets housed at low or control temperature. The feed conversion ratio was significantly affected by low temperature but not by diet. The heterophil/lymphocyte ratio was higher in chicks after one week in the cold, indicating mild stress. Blood triiodothyronine levels were significantly higher in birds after 1 and 4 weeks in the cold but thyroxin was not affected. 4. Organic Se supplementation increased relative lung weight at the control temperature, which might lead to greater respiratory capacity. Relative spleen weight significantly decreased in broilers fed diets supplemented with inorganic Se under cold conditions, a possible indication of chronic oxidative stress. 5. At the low temperature, supplementation with organic Se alone, or with inorganic Se and vitamin E increased glutathione peroxidase (GSHPx) activity and glutathione (GSH) concentration in the liver of broilers, which may indicate increased activity of birds' antioxidant defence against suboptimal environments.     

A large-scale outbreak of trichinellosis caused by Trichinella britovi in Turkey

An outbreak of trichinellosis occurred in Izmir, Turkey, between January and March 2004. The outbreak was caused by the consumption of raw meat balls made of beef deceptively mixed with pork infected with Trichinella britovi. A total of 1098 people who had consumed this food either in 14 restaurants or from the street vendors located in three different neighbourhoods, consulted six different healthcare centres with a wide range of clinical signs and symptoms. Of them, 418 (38.1%) patients fulfilled the criteria for the diagnosis of acute trichinellosis. The most commonly observed signs and symptoms were myalgia (89.2%), arthralgia (69.9%) and eyelid (67%) and facial oedema (65.8%). High levels of creatinine kinase (69.3%) and lactate dehydrogenase (93.8%) with leucocytosis (>10 000/mm(3), 58.9%) and eosinophilia (>1000/mm(3), 60.5%) were the most prominent laboratory findings. All, but 13 of these patients were treated with mebendazole or albendazole. Based on the physicians' assessments of disease severity, 78 (19%) patients were additionally given prednisolone in whom a significantly more rapid recovery of clinical signs and symptoms (e.g. fever, myalgia, facial and eyelid oedema) was observed, with a rapid improvement in leucocytosis, eosinophilia and muscle enzymes, compared with those, who had not received corticosteroids (P < 0.05). Beef illegally mixed with pork of unknown origin, by a wholesale butcher who had sold this product to restaurants and street vendors at a lower price than the prevailing market price of beef, was the cause of this large-scale outbreak in a country with a predominantly Muslim population.     

The venous drainage of the heart in porcupines (Hystrix cristata)

The venous drainage of the heart in porcupines (Hystrix cristata) was investigated. Each of the five adult porcupines (three males, two females) was injected with a coloured latex mixture via the V. cava caudalis for the demonstration of the cardiac veins. The dissection of the specimens revealed that the venous drainage of the heart in porcupines was made by the V. cordis magna, V. distalis ventriculi sinistri, V. proximalis ventriculi sinistri, V. cordis caudalis (the left marginal vein), V. cordis media and Vv. cordis dextrae. The cardiac veins were observed in a subepicardial course on the heart except for the R. interventricularis paraconalis. The R. interventricularis paraconalis showed an intramyocardial course until the middle of the sulcus interventricularis paraconalis, and a subepicardial course after this point. The V. cordis magna and V. distalis ventriculi sinistri opened to the sinus coronarius. The V. cordis caudalis and the V. cordis media drained into the V. cava caudalis. The venous drainage of the conus arteriosus was made by the left V. coni arteriosi opening to the R. interventricularis paraconalis, and by the right V. coni arteriosi which continued to the Vv. cordis dextrae.