Liquid chromatographic assay of tetracyclines in tissues of food-producing animals

A survey of the literature is presented on liquid chromatographic (LC) determination of tetracyclines in plasma, urine, and tissues of food-producing animals. Food Safety and Inspection Service (FSIS) research on tetracyclines during 1973-1984 is discussed, including the thin layer chromatographic qualitative identification method for tissues. Research on development of LC column packings for trace level chromatography of tetracyclines and anhydrotetracyclines is also discussed. Data are shown for recovery, ruggedness testing, and analyst qualification studies on the tentative version of the LC method.     

Fish assemblages of Red Sea backreef biotopes

• 1. Fish assemblages of shallow‐lagoonal biotopes (seagrass beds, coral patches, reef flat and sand) were examined within the Nabq Managed Resource Protected Area (MRPA), South Sinai, Egypt. This protected area supports a small‐scale artisanal Bedouin fishery, managed by gear restrictions and a network of no‐take zones (NTZs).
• 2. Coral patches showed highest species richness and diversity of fish, followed in order by the reef flat, shallow seagrass beds and sandy bottoms.
• 3. There were clear differences in fish assemblages between the biotopes surveyed, little differences between sampling areas and no significant differences in fish assemblages between no‐take and take zones, suggesting species characteristic of these shallow‐water biotopes are dispersed along the coast irrespective of fishing pressure.
• 4. Nine species (Acanthurus nigrofuscus, Asterropteryx semipunctatus, Cryptocentrus caeruleopunctatus, Cheilio inermis, Thalassoma rueppellii, Lethrinus mahsena, Lethrinus nebulosus, Parupeneus forsskali and Pomacentrus trilineatus) had a 95% correlation to the pattern of assemblage distribution, indicating these species are the most important determinants of the fish community.
• 5. Approximately one‐third of fishes recorded appeared to be juveniles, with seagrass beds having a particularly high proportion of juvenile fish, including several commercial species.
• 6. The structure of the fish assemblage and fish size suggests that shallow‐water biotopes in Nabq MRPA may be acting as nursery areas of commercial fish for the Bedouin fishery.

Copyright © 2006 John Wiley & Sons, Ltd.     

A comparative efficacy test of 1 versus 2 doses of CIRCOQ PCV2 subunit vaccine against naturally occurring PCV2-type d in piglets with high maternally derived antibodies (MDAs) on a Vietnamese swine farm

The aim of this study was to evaluate the protective efficacy of the CIRCOQ porcine circovirus type 2 (PCV2) subunit vaccine in piglets with high maternally derived antibodies (MDAs) against disease caused by natural infection with PCV2d. A total of 130 weaned, 21-day-old healthy pigs was allocated into 3 trial groups. The signs of respiratory disorder were higher in unvaccinated pigs than in vaccinated pigs at 13 to 17 weeks old (P < 0.05), 18 to 22 weeks old (P < 0.001), and 23 to 27 weeks old (P < 0.01). The unvaccinated pigs had an early rate of dermatitis at 8 to 12 weeks old (10.0%), 13 to 17 weeks old (30.0%), 18 to 22 weeks old (46.7%), and 23 to 27 weeks old (33.3%), while there were no cases of dermatitis in vaccinated pigs. There was a significant difference (P < 0.05) in the mortality of pigs in the unvaccinated group and the 2-dosed vaccinated group. PCV2 viremia was detected in the blood and peaked at 105 days old in both unvaccinated pigs (Ct-adj = 8.40) and pigs vaccinated with 1 dose (Ct-adj = 6.37), while no detectable PCV2 virus was found in the blood of pigs vaccinated with 2 doses. At 77 and 105 days old, the PCV2 viremia load (Ct-adj) of unvaccinated pigs and those vaccinated with 1 dose was significantly higher (P < 0.05) than that of the 2-dosed vaccinated pigs. The body weight (BW), average weight gain (AWG), and average daily gain (ADG) in both groups of vaccinated pigs were significantly higher (P < 0.05) than those of unvaccinated pigs. The study vaccine was significantly efficacious in protecting vaccinated pigs against clinical symptoms, blood viral load, and mortality, as well as improving productivity, compared with unvaccinated pigs.     

Mycobacterium ulcerans infections in two horses in south-eastern Australia

Two horses were diagnosed as having Mycobacterium ulcerans infections. The first was a 21-year-old Quarterhorse-cross mare living in Mallacoota (a coastal town near the border of New South Wales and Victoria, Australia) that presented with lichenification, hair-loss and oedema on a fetlock, which subsequently ulcerated, as well as a non-healing ulcer on the wither. The second horse was a 32 year-old Standardbred gelding from Nicholson, near Bairnsdale, Victoria, that had an ulcerated lesion on its caudal thigh. Histologically, there were characteristic changes seen with M. ulcerans infections in other species, including extensive necrosis without associated granulomatous inflammation. The organisms were seen in Ziehl-Neelsen-stained smears or sections of the lesions from both horses and were isolated in culture from the first horse. A definitive diagnosis was provided by real-time polymerase chain reaction targeting the M. ulcerans-specific insertion sequence, IS2404. Delayed identification of the infectious agent in the first case led to the use of suboptimal antimicrobial therapy, resulting in failure to control the infection and the horse was subsequently euthanased. The second horse was successfully treated following surgical debulking of the centre of the lesion and one session of aggressive cryosurgery. Mycobacterium ulcerans should be considered in the differential diagnosis of unexplained lichenification with oedematous and ulcerated skin lesions in horses living in regions where this organism is endemic.     

Exploring genetic diversity of lowland avocado (Persea americana Mill.) as a genetic reservoir for breeding

Genetic Resources and Crop Evolution - The avocado (Persea americana Mill.) is highly valued worldwide for its desirable nutritional properties and broader applications in the oil and...     

Potential impacts of projected sea‐level rise on sea turtle rookeries

• 1. Projected sea‐level rise (SLR) is expected to cause shoreline erosion, saline intrusion into the water table and inundation and flooding of beaches and coastal areas. Areas most vulnerable to these physical impacts include small, tropical low‐lying islands, which are often key habitat for threatened and endemic species, such as sea turtles.
• 2. Successful conservation of threatened species relies upon the ability of managers to understand current threats and to quantify and mitigate future threats to these species. This study investigated how sea‐level rise might affect key rookeries (nesting grounds) (n=8) for the northern Great Barrier Reef (nGBR) green turtle population, the largest green turtle population in the world.
• 3. 3‐D elevation models were developed and applied to three SLR scenarios projected by the IPCC 2007 and an additional scenario that incorporates ice melting. Results indicate that up to 38% of available nesting area across all the rookeries may be inundated as a result of SLR.
• 4. Flooding, as a result of higher wave run‐up during storms, will increase egg mortality at these rookeries affecting the overall reproductive success of the nGBR green turtle population. Information provided will aid managers to prioritize conservation efforts and to use realistic measures to mitigate potential SLR threats to the nGBR green turtle population. Copyright © 2009 John Wiley & Sons, Ltd.

     

Sulfamethazine blood/tissue correlation study in swine

Seventy market-weight hogs (90 to 113 kg) were used in a feeding study to determine the correlation of serum sulfamethazine concentrations with sulfamethazine concentrations in liver and muscle at time of slaughter. Test groups were fed medicated feeds prepared from commercial medicated premixes containing 110 g of sulfamethazine/metric ton for 30 days. Fifteen days before hogs were slaughtered, test groups were given maintenance feeds containing 1.1 to 13.9 g of sulfamethazine/metric ton and were fed these diets until slaughtered. Comparison of data from positive- and negative-control groups indicated that total withdrawal of sulfamethazine in the feed was not necessary for the liver to contain less than the allowed tolerance of 0.1 mg of sulfamethazine/kg of liver at slaughter. Feed concentrations of up to 2 g of sulfamethazine/metric ton could be tolerated in withdrawal feeds before liver sulfamethazine values exceeded 0.1 mg/kg of liver. Serum/tissue sulfamethazine ratios were erratic in hogs given 1.1 to 2.7 g of sulfamethazine/metric ton, but became less variable in hogs given greater than 5.7 g/metric ton. Feed concentrations greater than 8 g of sulfamethazine/metric ton produced values greater than 0.1 mg/kg of muscle and values of about 0.4 mg/kg of liver. When serum sulfamethazine concentrations alone were used as a predictor for tissue sulfamethazine values, 100% of the liver values exceeded 0.10 mg/kg of liver when sulfamethazine in serum was greater than 0.45 mg/L. However, 57.4% of samples having serum concentrations between 0.10 and 0.45 mg/L had associated sulfamethazine values greater than 0.1 mg/kg of liver. All hogs having serum sulfamethazine concentrations less than 0.1 mg/L had sulfamethazine concentrations less than 0.1 mg/kg of liver.