Weight-length relationships for selected fish species of the small-scale demersal fisheries of the south and south-west coast of Portugal

Weight-length relationships were estimated for 31 fish species from the south and south-west coasts of Portugal. These species, which are mainly sea breams (Sparidae), dominate the catches of the main fixed gears used in this region and account for more than 50% and 40% of the total fish landings by weight and by value.     

Dynamics of the free-living stages of sheep intestinal parasites on pasture in the North Island of New Zealand. 2. Weather variables associated with development

Abstract

AIM: To identify weather variables associated with the development of eggs of Teladorsagia (=Ostertagia) circumcincta, Trichostrongylus colubriformis and Haemonchus contortus to third-stage infective larvae (L3) under a range of climatic conditions on pasture in the North Island of New Zealand.

METHODS: Sheep faeces containing known numbers of eggs of all three nematode species were deposited on, or buried in, pasture plots at three sites, viz coastal Manawatu, Upper Hutt Valley, and East Cape hill country. Development was measured by recovering L3 from faeces, herbage and soil 28–31 days after deposition, on 13–18 occasions between January 2005 until July 2006. Weather data were recorded at each site, and the association between weather variables and number of L3 recovered was analysed using subsets regression to select best-fitting models from several candidate variables, after adjustment for efficiency of recovery of L3. A multiple linear regression model was then developed for each species, to select weather variables that had both significant and substantive effects on the number of L3 recovered.

RESULTS: For all species, mean daily temperature was the bestpredictor of the number of L3 recovered (p=0.001). For T.circumcincta the final model included mean daily temperature and soil temperature (R²=51%), and for T. colubriformis the model only included mean daily temperature (R²=55%). For development of H. contortus, mean daily temperature was the most significant variable, but moisture in the form of rainfall entropy, i.e. the temporal distribution of rainfall, overthe first 14 days was also significant in the final model (R²=34%).

CONCLUSIONS: Temperature was the most important determinant of developmental success of free-living nematodes on pasture at the study sites, and probably also for other parts ofNew Zealand with similar climates. Moisture was not significant in the development of T. circumcincta or T.colubriformis, implying that under the generally moist temperate climate in New Zealand, moisture is seldom limiting for development of these species. Haemonchus contortusappeared to be sensitive to moisture availability and precipitation in the first 14 days after deposition of faeces. The results of this study will be further developed as part of species-specific climate-driven models of parasite development in New Zealand.     

Salmonella Brandenburg — emergence of a variant strain on a sheep farm in the South Island of New Zealand

AIM: To compare the rectal and I/V administration of tramadol in dogs, to assess both its pharmacokinetic properties and absolute bioavailability.

METHODS: After rectal administration via suppositories and I/V injection of tramadol (4 mg/kg), the concentration of tramadol and its main metabolites, O-desmethyl-tramadol (M1), N-desmethyl-tramadol (M2) and N,O-didesmethyl-tramadol (M5), were determined in plasma, using high-performance liquid chromatography (HPLC). A balanced cross-over study was used, involving six male Beagle dogs.

RESULTS: Plasma concentrations after rectal and I/V administration were fitted on the basis of mono- and bi-compartmental models, respectively. Following rectal administration tramadol was detected from 5 minutes up to 10 hours, in lesser amounts than M5 and M2, while M1 was detected in negligible amounts. Following I/V administration tramadol was detected up to 10 hours, M2 and M5 were detected at similar concentrations, and M1 was present at low concentrations. The area under the curve (AUC) of the three metabolites did not differ significantly after either route of administration of tramadol. The absolute bioavailability of tramadol via rectal administration was 10 (SD 4)%.

CONCLUSIONS: After rectal administration of tramadol suppositories, absorption of the active ingredient was rapid, but its metabolism quickly transformed the parent drug to high levels of M2 and M5.

CLINICAL RELEVANCE: In the dog, rectal pharmaceutical formulation of tramadol would have a different pharmacokinetic behaviour than in humans.     

Thermal and Chemical Properties of Gelatin from Tilapia (Oreochromis niloticus) Scale

ABSTRACT

Gelatin from the scale of Nile tilapia was extracted and characterized chemically, thermally, and structurally. Scales of Nile tilapia were subjected to acid pretreatment and extraction with water at 60°C. The process yielded 12.1% (m/m) on a dry basis. The 6.67% gelatin solution had a gel strength of 233.5 ± 14g. The amino acid composition revealed that 20.02% was comprised of imino acids and glycine (34.49%) as the most abundant amino acids. The scale gelatin had α1, α2, and β subunits and was thermally stable up to 200ºC. The Fourier transform infrared spectrum showed absorption in the regions of amides A, I, II, and III. The characterization of tilapia scale gelatin showed that the obtained product was similar to commercial gelatin, thereby demonstrating its potential application.     

Effect of Calea serrata Less. n-hexane extract on acetylcholinesterase of larvae ticks and brain Wistar rats

The stem bark of Acacia oxyphylla Graham ex Bentham is used as an anthelmintic by the natives of Mizoram (North-East India). Therefore, the aim of the study was to assess the effect of the active compound isolated from A. oxyphylla on the tegument of adult Raillietina echinobothrida and Ascaridia galli. The test parasites R. echinobothrida and A. galli were incubated in physiological buffered saline containing 0.0005, 0.001, 0.05, 0.1 and 1mg/ml of the isolated compound. The alterations in the tegument of the parasites post paralysis were examined using electron microscopes. The compound reduced the cestode's motility soon after incubation, but did not induce paralysis in the nematodes till about 11-14 h at highest concentration. The compound caused extensive digestion of cestode tegument as evident by electron microscopy. Disorganization of muscle bundles, loss of cell-cell contact, extreme vacuolization and oedema were some of the changes observed. Loss of cellular organelles combined with distortion of those present was markedly noted throughout the parasite tissue. Deformation and disorganization of epicuticle, disruption of mitochondrial and nuclear membrane were also observed in nematode exposed to the active compound of the plant. Substantial structural deformities in the treated parasites are indicative of an efficient vermicidal activity of the isolated compound against cestodes and nematodes.