Sampling Shrimp Populations in Hatcheries

Abstract.– Shrimp populations were estimated with volumetric sampling techniques during different phases of hatchery operations. Factors considered which might effect precision of estimates included stage age, density and temperature. Estimates of nauplii were obtained with coefficient of variation values smaller than 3% when nauplii were concentrated in 20-L buckets and smaller than 8% when released in 13,000 L of water in larval rearing tanks. In both cases estimates were of sufficient precision to make management decisions for routine hatchery work. A technique was developed for estimating shrimp populations in larval rearing tanks with coefficient of variation values smaller than 15%. Volumetric sampling of postlarvae older than PL₄, in larval rearing tanks was highly variable due to the tendency of shrimp to congregate and attach to tank walls and bottoms. A direct relationship was observed between postlarval density and the precision of population estimates in harvest buckets. Water temperature and postlarval age did not affect precision at the densities and ages studied. These findings have important implications for commercial transactions. Industry standards utilizing coefficient of variation are recommended for larvae and postlarvae population estimates.     

The Effect of Storage on Ammonia Concentration in Canine Packed Red Blood Cells.

Objective: To determine the effect of storage on ammonia concentration in canine packed red blood cell (pRBC) units.
Design: In vitro and in vivo study.
Setting: University Veterinary Teaching Hospital.
Interventions: Ammonia concentration was measured in 7 units of canine pRBC prepared in citrate-phosphate-dextrose (CPD) and Adsol^a on Days 1 and 35 of storage. Ammonia was measured in 4 additional units of canine pRBC on Days 0, 7, 14, 21, 28, and 35. Plasma ammonia was also determined in 5 anemic dogs receiving pRBC.
Measurements and Main Results: Ammonia concentration increased from 73 ± 15 mmol/L (mean ± SD) on Day 1 to 800 ± 275 mmpl/L on Day (p<0.001). When measured every 7 days in 4 units of canine pRBC, ammonia concentration increased from 23 ± 8 mmol/L on Day 0 to 179 ± 13 mmol/L (Day 7), 276 ± 56 mmol/L (Day 14). 383 ± 47 mmol/L (Day21), 466 ± 30 mmol/L (Day 28), and 562 ± 27 mmol/L (Day 35) (p<0.05 for all comparisons). In a preliminary study, plasma ammonia concentration measured in blood samples from 5 anemic dogs without primary liver disease immediately before and after transfusion with 5–10 ml/kg of stored pRBC remained in the normal reference range.
Conclusions: The ammonia concentration in stored canine pRBC increased markedly with time. In this preliminary study, ammonia concentrations in dogs without primary liver disease did not increase above the reference range after transfusion with pRBC.     

Clinical and Clinicopathologic Characteristics of Ovine GM-1 Gangliosidosis

Ovine GM-1 gangliosidosis is an inherited lysosomal storage disease. Nine lambs affected with the disease were studied to characterize clinical signs and to determine if there were any pathognomonic clinicopathologic abnormalities. Evaluation included physical, ophthalmic, and neurologic examinations, complete blood counts, serum enzyme and electrolyte analyses, urinalyses, cerebrospinal fluid analyses, blood gas analyses, roentgenograms, electromyograms, and electrocardiograms. Two affected lambs had clinicopathologic tests performed before and after the onset of clinical signs. The only consistent abnormalities recognized were nonspecific signs referable to the central nervous system; predominantly ataxia, conscious proprioceptive deficit most severe in the hind limbs, blindness, and recumbency. Lambs continued to eat and drink, though at diminished levels and with loss of body condition. It was concluded that there are no pathognomonic clinicopathologic abnormalities associated with ovine GM-1 gangliosidosis, and antemortem diagnosis requires enzyme assay of leukocytes or cultured fibroblasts, or lectin histochemistry of tissues obtained by biopsy. Lysosomal storage diseases should be considered among the differential diagnoses in young animals presenting with early neonatal death or with nonspecific neurological signs, in concert with an absence of diagnostic clinicopathologic findings.     

SEPTIC COXOFEMORAL ARTHRITIS AND OSTEOMYELITIS IN A DOG

An 8-year-old male Labrador retriever presented with a rear limb lameness cased by an osteolytic lesion of the left acetabulum and femoral head and neck. Initial bone biopsy study was nondiagnostic. Histopathologic study and culture of the subsequently excised femoral head and neck revealed a Staphyloccocus intermedial arthritis and osteomyelitis. Neoplash was ruled out on the basis of histopathologic analysis.     

The toxicity of mixtures of a pyrethroid with organophosphorus insecticides to Tetranychus urticae Koch

Laboratory studies of the cotoxicity of a pyrethroid insecticide, fenvalerate, and several organophosphorus insecticides against the two-spotted spider mite, Tetranychus urticae Koch, showed that a useful degree of potientation of toxicity occurred. The most effective combination of fenvalerate and azinphos-methyl was found to be a 1:1 ratio. Phosphates and phosphorodithioates in combination with fenvalerate were more toxic than phosphoromonothioates. The results suggest a practical method of improving the acaricidal activity of pyrethroid insecticides.     

The pyrethrins and related compounds. Part XXII. Preparation of isomeric cyano-substituted 3-phenoxybenzyl esters

Preparation of 3-phenoxybenzyl chrysanthemates and their dihalovinyl analogues substituted with a cyano group at the 2-, 6-, (R)-α-, or (S)-α- positions is described. The (R)- and (S)- isomers of α-cyano-3-phenoxybenzyl esters of 2,2-difluoro-, -dichloro-, and -dibromo-vinyl analogues of cis- and trans- chrysanthemic acid are separated chromatographically, as are the separate pairs of enantiomers of fenvalerate, (RS)-α- cyano-3-phenoxybenzyl (RS)-2-(4-chlorophenyl)-3-methylbutyrate. An optically active ester of α-cyano-3-phenoxybenzyl alcohol (obtained using D -oxynitrilase) with 2,2,3,3-tetramethylcyclopropanecarboxylic acid is synthesised.     

Build-up and subsequent decline of residues of quintozene and hexachlorobenzene in lettuce in sequential crops

The build-up and decline of quintozene and hexachlorobenzene residues in protected lettuce, resulting from one to five treatments of the soil (each of 35 g m-2) with a quintozene formulation, have been studied. Residue levels were monitored in each experimental crop during growth until harvest. Residues in the soil at harvest were also determined. Quintozene residues in the harvested lettuce were in the range < 0.02–0.80 mg kg^?1 and those of hexachlorobenzene were in the range < 0.02–0.05 mg kg^?1 (expressed on a fresh weight basis). Residue levels in the soil were 5.4–231 mg kg^?1 for quintozene, and 0.20–5.4 mg kg^?1 for hexachlorobenzene (expressed on a dry weight basis). Under the experimental conditions of the trial there was no significant build-up of quintozene or hexachlorobenzene in harvested lettuce, even after five treatments to the same site.     

Uptake of the systemic fungicide triadimefon by clover and its effect on symbiotic nitrogen fixation

Clover is frequently grown in rotation with cereals in order to increase soil nitrogen. The systemic fungicide triadimefon, widely used against cereal pathogens, is readily taken up from soil by clover and degraded to a single major metabolite. Plant weight and symbiotic nitrogen fixation by Rhizobium trijolii are affected only by concentrations of triadimefon in soil that are much in excess of those likely to be encountered in practice. Triadimefon residues are thus unlikely to affect nitrogen fixation by clover under field conditions.