Induced Maturation and Spawning of the Chinese Catfish Clarias fuscus

Chinese catfish ( Clarias fuscus ) were successfully spawned in Hawaii using human chorionic gonadotropin (HCG) at dosage rates of two and four international units (IU) per gram body weight. Fish not injected with HCG did not produce viable eggs. Successful spawns with HCG occurred between May and October. Hatch rates of up to 80% were obtained during June, July, and August for those fish given either a 2 or 4 IU per gram body weight injection of HCG. Fish spawned in either May or October yielded significantly higher hatch rates when injected with 4 rather than 2 IU per gram body weight. Fish held at elevated temperatures (28 to 30 C) prior to the normal spawning season developed significantly larger oocyte diameters, 60 days earlier than fish held under ambient temperature conditions (21.5 to 24 C). Photoperiod manipulation at ambient temperature conditions was associated with earlier oocyte maturation, but photoperiod effects were much less important than temperature.     

0–7–21 Radiation Therapy for the Treatment of Canine Oral Melanoma

Eighteen dogs with malignant melanoma of the oral cavity were treated with high-dose per fraction (0–7–21) radiation therapy. Eight hundred cGy was administered on days 0, 7, and 21 for a total dose of 2,400 cGy in 3 weeks. Of 17 dogs evaluated, 9 (53%) had a complete remission and 5 (30%) achieved a partial remission with an overall response rate of 83%. Local failure occurred in 2 of the 9 dogs where a complete response was initially observed. One dog died of intercurrent disease, and one died of metastatic disease without evidence of local recurrence. Five dogs are alive and free of disease 9 to nineteen months from the initiation of therapy. The 0–7–21 protocol was well-tolerated, and acute radiation reactions were low-grade and limited to the skin. The results of this study demonstrate that oral melanomas in dogs are responsive to radiation. 0–7–21 radiation therapy offers a viable alternative to radical excision, especially when tumor volume or location would require cosmetically or functionally debilitating surgery.     

Particle Size Distribution in Two Lipid Emulsions Used for the Enrichment of Artemia nauplii as a Function of Their Preparation Method and Storage Time

The present study examined the distribution of particle sizes in two experimental standardized lipid emulsions (distributed by ICES, International Council for the Exploration of the Sea) as a function of the preparation method (hand shaking or ultrasonic blending) and as a function of storage time. A 24-h enrichment trial compared the incorporated HUFA levels in the nauplii of Artemia franciscana .
The emulsion droplets in the 50% HUFA emulsion (ICES 50, ethyl ester based) were much smaller than in the 30% HUFA emulsion (ICES 30, triacylglycerol-based) in which 90% of the droplets had a diameter below 12.3 μm as compared to 1.3 pn in ICES 50. The blending method highly affected particle sizes. High-shear blending instead of the classical hand shaking of the emulsion of both ICES 30 and 50 reduced the mean particle size from 5.06 to 1.07 μm and from 0.38 to 0.11 μm, respectively. The particle size distributions remained stable during the 1-wk storage, suggesting the absence of agglomeration or bacterial development. The fatty acid composition of 24-h enriched Artemia reflected differences in the HUFA profile of the emulsions, but was independent of observed differences in the size of the particles.     

Infectious diseases of New-World camelids (NWC)

Although there are notable infectious conditions that are capable of producing clinical disease in the NWC, overall, these species are quite healthy. Of the bacterial diseases, enterotoxemia caused by Clostridium perfringens types C and D would be deemed the most significant in North America, while type A also would be regarded as important in South America. Other important bacterial infections of potential concern are tuberculosis, Johne's disease, anthrax, malignant edema, actinomycosis, tetanus, and the South American condition referred to as alpaca fever, which, to date, has not been observed in North America. Fungal infections include classical ringworm, principally caused by Trichophyton spp., and the cases of coccidioidomycosis that are associated with the arid desert lands of the southwestern United States. Most notable of naturally occurring viral infections in the NWC would be rabies, ecthyma, and a recently described blindness neuropathy that has been associated with the equine herpesvirus I. NWC can be infected experimentally with agents causing hoof-and-mouth disease and vesicular stomatitis, but naturally occurring cases do not seem to occur. Serological evidence of exposure to many viral agents, including blue tongue, parainfluenza 3, bovine respiratory syncytial virus, bovine herpesvirus I, bovine viral diarrhea, influenza A, and rotavirus, has been demonstrated; however, no clinical disease associated with these agents, as yet, is apparent.     

Genetic analyses of resistance of the wheat differential cultivars Carstens V and Spaldings Prolific to two races of Puccinia striiformis

Genetic analysis of resistance of wheat seedlings to two races of Puccinia striiformis was conducted on F₁, F₂ and F₃ generations from crosses Carstens V (CV) × Lee, Spaldings Prolific (SPA) × Lee and CV × SPA. F₂ generations from crosses of CV and SPA with Strubes Dickkopf (SD) were also studied. The plants were classified into six resistance classes and analysed by factorial correspondence analysis and nonhierarchical classification. The two P. striiformis isolates tested were a French isolate of race 43E138 and a Lebanese isolate of race 2E16, selected for the differences in their virulence spectra for the common differential cultivars Strubes Dickkopf and Nord Desprez. Resistance of CV and SPA was recessive and dominant to races 43E138 and 2E16, respectively. CV possessed three or four resistance genes, one of them being expressed with both races. Two genes of CV had a cumulative effect for resistance to 43E138 and two or three gave dominant resistance to 2E16. SPA had three resistance genes, all of which gave resistance to 2E16 and two of which also gave resistance to 43E138. SPA had one gene in common with CV for resistance to both races. Furthermore, the gene for resistance to race 2E16 in CV and SPA was allelic with a gene in SD, and was probably Yr25 .     

The Welfare of Laboratory Animals

Veterinary Research Communications -     

Changes in enzymic activity and distribution of acid-soluble,amino acid-nitrogen in soil during nitrogen immobilization and mineralization

During a period of immobilization of nitrate-¹⁵N and mineralization of organic N in a sandy-loam, changes were recorded in: (a) the concentration of an added carbon source, glucose-¹⁴C: (b) evolution of ¹⁴CO₂: (c) bacterial populations; (d) distribution and concentration of newly-synthesized, acid-soluble, amino acid-¹⁵N; and (e) distribution and activities of several oxidative and hydrolytic enzyme systems.Added glucose-¹⁴C was rapidly metabolized by the soil microflora. After 1.5 day's incubation, when only 3.6 per cent of the added glucose was present, 68 per cent of the ¹⁴C remained in the soil-microbial system. During this period there was a marked increase in viable bacterial numbers and an almost complete immobilization of nitrate-¹⁵N. On continued incubation, microbial metabolites were oxidized at decreasing rates, the more rapid phase corresponding to a period of net decline in the viable bacterial population.Soil was fractionated by a relatively mild procedure into components containing: (a) extractable proteins; (b) extractable amino acids and peptides; (c) particulate material containing microbial cells, cell debris and material bound to larger soil particles; and (d) microbial metabolites mainly bound to soil colloids. Although the total, acid-soluble, amino acid-¹⁵N remained relatively constant for about 50 days, there were marked changes in their concentration in different fractions, especially in the extracts and in the fraction containing fine colloidal material. However, the relatively large decline in labelled, acid-soluble, amino acid-¹⁵N occurred during the active phase of oxidation of microbial metabolites when little net mineralization of labelled compounds occurred.Increases in enzymic activities generally coincided with increased viable bacterial populations although there were some exceptions, notably casein and benzoyl arginine amide-hydrolysing enzymes. The stabilities of the newly-formed enzymes varied markedly. The greatest relative changes in activity occurred with the casein-hydrolysing enzymes. Their activity reached a maximal value after the main flush of bacterial growth, was short-lived and was to a large extent extractable. The formation and disappearance of this extracellular proteolytic activity coincided approximately with that of a secondary peak of extractable, newly-synthesized, protein-¹⁵N. In general however, changes in enzymic activity could not be identified with changes of protein-¹⁵N concentrations of the different fractions.