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Provision of a suitable feed is paramount for the ongoing success of spiny lobster culture. This study compared and evaluated the performance of seven diets for first instar juvenile spiny lobster Panulirus argus [5–6 mm carapace length (CL)] based on growth rates, survival, and feed conversion ratio. Results demonstrated that a seafood-based juvenile formulation produced the fastest growth rate (3.49% weight gain day−1 and 0.90% CL increase day−1 over a 28-day period). These growth rates were also reflected by a low feed conversion rate (3.04) for this formulated feed. Similar results were also obtained for juveniles fed a frozen seafood diet, however, frozen brine shrimp, Artemia salina (both enriched and un-enriched), frozen enriched mysis shrimp, a dry pellet, and a meal-based juvenile formulation did not produce consistent growth rates. Survival rates ranged between 38% and 85% and demonstrate that juvenile lobsters have better likelihoods of survival in captive culture environments compared to the wild. Although further nutritional refinement is recommended, the results from this research have significant implication for the possible expansion of juvenile spiny lobster growout to a larger scale. 相似文献
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1. Laying hens were fed osteolathyrogens, either semicarbazide hydrochloride at 0.3 or 0.4 g/kg or β-aminopropionitrile fumarate at 0.5 or 0.6 g/kg diet to examine their effects on eggshell quality. 2. Shell quality characteristics considered for evaluation were shell surface area, shell thickness, shell weight, percentage shell, shape index and the specific gravity of eggs. Measurement of shell quality traits revealed that the hens fed osteolathyrogens laid eggs with significantly lower specific gravities and proportion of shell by weight. These differences were not explained by differences in shell thickness or weight or the shape index of eggs. 3. It was concluded that osteolathyrogens cause hens to lay eggs with poor shell quality and such eggs are weak and fragile. 相似文献
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The culture of Litopenaeus vannamei in inland low salinity waters is currently being practiced in various countries around the world. These environments are often deficient in key ions essential for normal physiological function, including potassium (K+) and magnesium (Mg2+). Farmers have sometimes been able to counteract ionic deficiencies in the water profile by adding mineral salts containing sources of K+ and Mg2+. The purpose of this study was to explore the possibility of correcting deficiencies of K+ and Mg2+ in the water profile with dietary supplementation of these minerals. Two separate 7‐week experiments were conducted in 4.0 g−1 artificial low salinity water to evaluate the effects of mineral supplements (K+, Mg2+ and NaCl) to diets of L. vannamei reared in low salinity waters. In trial 1 seven diets were formulated (10 g NaCl kg−1, 20 g NaCl kg−1, 150 mg kg−1 Mg2+, 300 mg kg−1 Mg2+, 5 g K+ kg−1, 10 g K+ kg−1, and a basal diet to serve as a control). Minerals were added in the form of purified potassium chloride (KCl), magnesium chloride (MgCl2·6H2O) and NaCl. Trial 2 evaluated the use of a coating agent for the Mg2+ and NaCl treatments, while a K+ amino acid complex was utilized in the K+ treatments to reduce mineral leaching. Trial 2 was performed using similar treatment levels as trial 1. Shrimp survival and growth were assessed in both experiments. Results from trial 1 indicated no significant differences in survival, growth or percent weight gain. Results from trial 2 revealed no significant differences in survival and growth in the NaCl and Mg2+ treatments. However, significant differences in growth (P < 0.05) were observed when using the 10 g K+ kg−1 treatment, suggesting that dietary supplementation of a K+ amino acid complex may help improve growth of the species in low salinity waters. 相似文献
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A light and electron microscope study of epitheliocystis in juvenile steelhead trout, Salmo gairdneri Richardson 总被引:1,自引:0,他引:1
Abstract. Ultrastructural analysis of epitheliocystis organisms from gills of anadromous juvenile steelhead trout, Salmo gairdneri Richardson, revealed the presence of several distinct forms. Two oval infectious organisms resembled previously described agents and had chlamydia-like characteristics. One form had a distinct oval head region from which a tail-like structure projected. These prokaryotic forms have an ultrastructural appearance which has not been described in previous reports of epitheliocystis. Morphological analyses of gill epithelial cells of S. gairdneri suggest that each cyst remains contained within the cytoplasm of a single host cell. 相似文献
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MARK G. PAPICH LLOYD E. DAVIS CAROL A. DAVIS 《Journal of veterinary pharmacology and therapeutics》1986,9(4):359-369
Procainamide hydrochloride was administered to ouabain-intoxicated dogs to determine an antiarrhythmic plasma concentration of procainamide. Ventricular arrhythmias were produced in dogs following intravenous injections of ouabain. After a sustained ventricular tachycardia was achieved, procainamide was administered and plasma samples collected for assay. Plasma procainamide was assayed by fluorescence polarization immunoassay. Procainamide was administered at increasingly higher constant rate infusions in order to achieve intermittent, steady-state plasma concentrations. Infusion rates were calculated on the basis of previous pharmacokinetic information. All six dogs that received procainamide converted to a normal sinus cardiac rhythm after attaining a mean plasma concentration of 33.8 micrograms/ml with a range of 48.5 micrograms/ml-25.0 micrograms/ml. It was observed that the computer-generated prediction of plasma concentrations based upon previous pharmacokinetic data produced an underestimate of the actual plasma concentrations. These data may suggest that plasma concentrations of procainamide for controlling some cardiac arrhythmias in dogs may be higher than plasma concentrations cited for human patients. 相似文献
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Rats receiving occasional brief electric shocks pressed a bar, which caused them to be injected with amobarbital sodium, more frequently than the control rats to which they were yoked and which were injected when their partners pressed but whose own bar activated only a recorder. This differential effect was not shown by pairs run without shocks. 相似文献
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