Tolerance of Juvenile Red Drum Sciaenops ocellatus to Rapidly Decreasing Water Temperatures

This study assessed the potential mortality of pond-reared juvenile red drum Sciaenops ocellatus subjected to rapid declines in water temperature simulating cold front activity. Fish acclimated in an earthen pond at ambient temperature and photoperiod were introduced into a recirculating aquarium and biofiltration system when pond water temperatures decreased to 20, 18, 16, 14, 12, and 10 C. Fish were stocked according to size group into 10 aquaria containing filtered pond water at 9 ± 1‰ salinity and temperature matching the acclimation temperature. Fish were acclimated to the aquaria for 3 d, subjected to a 6 C decrease over 24 h, and then held for 72 h. No mortalities were observed in any trial. The results suggest that if juvenile red drum are maintained in water with salinity around 9‰, they should survive the passage of most cold fronts.     

Toxicology of selected pesticides, drugs, and chemicals. Zinc

Zinc poisoning in small animals has been described in dogs, cats, birds, and ferrets, but the dog appears to be the species most often affected. Ingestion of zinc-containing metallic objects, including pennies, and zinc oxide ointments has been associated with the majority of the toxicoses. Clinical signs include anorexia, vomiting, diarrhea, hemolytic anemia, kidney dysfunction, and possible liver and pancreatic abnormalities. Treatments that have proven efficacious include fluid diuresis, blood transfusions as needed, general supportive care, and removal of the source of zinc. Further evaluation of the benefit of chelation therapy is urgently needed.     

Production of the Freshwater Prawn Macrobrachium rosenbergii Stocked as Juveniles at Different Densities in Temperate Zone Ponds1

Juvenile freshwater prawns Mucrobruchium rosenkrgii (mean wet weight = 0.75, 1986 or 0.17g, 1985) were stocked into 0.06–0.07 ha earthen ponds at densities ranging from 39,536 to 118,608/ha during two separate growing seasons. After growout periods ranging from 135 to 142 days, survival was from 54.3% to 89.9% (x = 77.0%). Mean prawn weight at harvest ranged from 15.0 to 44.3g and decreased with increasing stocking density. The larger stocking weight of prawns was associated with harvest weights that were 16.8 to 39.6% greater than those achieved with the smaller stocking weight at comparable stocking densities. Stocking of juveniles of the proper size and the effective management of the social structure of M. rosenkrgii appear to be critical to the success of intensive pond culture in temperate climates where the length of the growing season is restricted.     

Evaluation of a spray-dried artificial diet for larval culture of freshwater prawn, Macrobrachium rosenbergii, and striped bass, Morone saxatilis

Larvae of the freshwater prawn, Macrobrachium rosenbergii (De Man), and the striped bass, Morone saxatilis (Walbaum), were fed artificial diets manufactured by a spray-drying process or live Artemia nauplii , separately or in various combinations. Spray-dried diets were neutrally buoyant, water stable (low protein leaching rate), and were satisfactorily consumed as verified by the observation of full guts after feeding. Survival and growth of larvae fed live Artemia nauplii was significantly greater than those of larvae fed spray-dried diets. Lowest survival and growth rates were observed when larvae were fed artificial diets exclusively from the onset of exogenous feeding. Survival rates were positively related to the duration of feeding live Artemia nauplii before weaning to artificial diets. The poor performance associated with spray-dried artificial diets may be the result of the digestive capabilities of the larvae of caridean shrimp and striped bass being insufficient to process compact, dense particles.     

酵母培养物对斑点叉尾鮰幼鱼生长性能的影响

以斑点叉尾鮰为对象,研究饲料中添加不同比例的酵母培养物[达农威水产益康(DVAQTM)]对其幼鱼成活、生长和饲料系数的影响。基础饲料蛋白含量为32%,赖氨酸含量为需要量的85%(斑点叉尾鮰赖氨酸在饲料蛋白质中的适宜含量5.1%),其余必需氨基酸均满足其需要量,分别向基础饲料中添加酵母培养物0.03%0、.06%和0.12%,且基础饲料中减少一定量的玉米,制成试验饲料,进行为期12周的生长试验。试验在水族箱(75 L)中进行,每个处理设4个重复,每个重复放养10尾鮰幼鱼(平均体重为4.5 g)。研究结果表明0,.06%和0.12%添加组鮰成活率均为100%,略高于对照组(97%)。0.06%添加组鮰幼鱼增重率较对照组平均提高19%,饲料系数降低13%。0.12%添加组较对照组增重率平均提高22%,饲料系数降低15%。因此,饲料中添加酵母培养物可提高斑点叉尾鮰幼鱼的生长性能。     

Mast cell tumors in three ferrets

Pruritic open skin lesions (5 mm diameter) on the thorax, neck, or head of 3 ferrets were diagnosed as mast cell tumors. Diagnosis of the tumors was based on histologic examination of biopsy specimens. Histologic diagnosis was necessary because the lesions had been treated as mycotic or bacterial ulcers and did not respond to conventional treatment. Excised mast cell tumors did not recur, and malignant behavior of the tumors was not observed.     

Calcium oxalate stones in feline littermates.

Two feline littermates were diagnosed with calcium oxalate uroliths. Both had been maintained on a commercially available dry diet with reduced magnesium and urine acidifying properties. One female littermate was diagnosed by visualising the stones by radiographs while the second littermate, also female, became blocked when one of the uroliths lodged in the urethra. Two other, unrelated cats in the household, of similar age and raised under the same conditions, did not develop calcium oxalate uroliths.