Molecular endocrine changes of Gh/Igf1 axis in gilthead sea bream (<Emphasis Type="Italic">Sparus aurata</Emphasis> L.) exposed to different environmental salinities during larvae to post-larvae stages

The influence of acclimation of the euryhaline gilthead sea bream (Sparus aurata) larvae/post-larvae to brackish water on growth, energetic contents, and mRNA levels of selected hormones and growth-regulating hypothalamic neurohormones was assessed. Specimens from 49 days post-hatching were acclimated during 28 days to two different environmental salinities: 38 and 20 psu (as brackish water). Both groups were then transferred to 38 psu and acclimated for an additional week. Early juveniles were sampled after 28 days of acclimation to both salinities and one week after transfer to 38 psu. Pituitary adenylate cyclase-activating peptide (adcyap1; pacap), somatostatin-I (sst1), growth hormone (gh1), insulin-like growth factor-I (igf1), and prolactin (prl) mRNA expression were all studied by QPCR. Post-larvae acclimated to 20 psu showed better growth performance and body energetic content than post-larvae maintained at 38 psu. prl, adcyap1, and igf1 mRNA expression levels increased in 20-psu-acclimated post-larvae but decreased upon transfer to 38 psu. GH1 expression did not show significant changes under both experimental conditions. Our results suggested an enhanced general performance for post-larvae in brackish water, supported by the actions of adcyap1, igf1, and prl.     

Genetic structure and genetic relatedness of a hatchery stock of Senegal sole (Solea senegalensis) inferred by microsatellites

Solea senegalensis is a fish species in an early stage of domestication. A commercial hatchery in southern Spain experienced a dramatic failure in spawning and embryo survival, after incorporation into the broodstock of fish reared in their hatchery. To assess the impact of management on the stock quality, a population genetics study was made of adult broodstock present at this hatchery in 2000. The broodstock was composed of a group of fish of wild origin and two more groups from F₁ progeny. A set of eight microsatellite loci was used to compare genetic variability among the three groups and to establish the relationships between pairs of individuals within each group.Individuals from F₁ origin showed a substantial reduction in genetic variability when compared to those from the wild. There was a greater than 50% decrease in the number of alleles per locus corrected by sample size and 16% and 26% reductions in H_e values in the two F₁ groups, respectively. The degree of genetic relationship between individuals, evaluated by the relatedness estimator, rxy, and by graphical approaches, revealed a high proportion, almost 75%, of full-sibs and half-sibs in both F₁ groups, which might account for the reduction in overall variability. The high proportion of siblings also suggests a reproductive pattern in this stock in which few individuals breed successfully. This mating behaviour, along with factors inherent to selection and management systems, might be responsible for the negative effects on the reproductive capacity of the stock.     

Predatory aggression in a German shepherd dog

This article presents a clinical case of predatory aggression that represents a problem for public health. The patient was a 2-year-old male German shepherd referred to the behavior clinic at the School of Veterinary Medicine owing to its aggressive behavior toward people and other dogs. The dog tended to form a pack with the other dogs of the household and killed neighborhood dogs, cats, hens, and rabbits. The presumptive diagnosis was “predatory aggression” associated with “territorial and protective aggression.” The risk analysis determined that the dog should be euthanized. Nevertheless, the owner refused, and hence behavior modification and drug therapy were recommended. A year later, the dog killed again (another dog), indicating that despite the drug and behavioral treatment, it is likely that its predatory aggression will never be resolved.     

Toxocara canis: proteinases in perivitelline fluid from hatching eggs

Developing larvae of Toxocara canis may secrete several kinds of enzymes within the egg perivitelline fluid (EPF) prior to and during hatching. In particular, proteinases in EPF could play a role in larval emergence within the host gastrointestinal lumen but its presence and nature is unknown. In this work, proteolytic activities in hatching fluid of T. canis were identified and analysed by substrate gel electrophoresis at different pH values and by using type specific protease inhibitors. Three bands of 91, 68 and 38 kDa showed gelatinolytic activity and all proteinase activity from EPF was of the aspartic-type since it was inhibited by pepstatin A. Interestingly, a significantly higher proteolytic activity was observed at acidic pH (< or =5.5). These data suggest that T. canis developmentally secretes and accumulates in EPF aspartic proteinases with a pH-dependent activity that might help the parasite to take advantage of conditions in the host gastrointestinal microenvironment where egg hatching is induced and executed.     

COMPUTED TOMOGRAPHIC FINDINGS IN OVINE COENUROSIS

Computed tomographic imaging was conducted in twenty ewes with cerebral coenurosis. CT imaging allowed precise evaluation of the size and location of the cyst, which appeared as a hypoattenuating structure with a mass effect. No meaningful correlation between clinical signs and the location of parasitic cyst was detected.     

Monitoring forage production for farmers’ decision making

Objective management of grazing livestock production systems needs monitoring of forage production at the managerial unit level. Our objectives were to develop a system that routinely estimates forage above-ground net primary production (ANPP) at the spatial and temporal resolution required by farmers in the Pampas of Argentina, and to facilitate adoption of the system by end users as a managerial support tool. Our approach was based on the radiation use efficiency (RUE) logic, which proposes that ANPP is determined by the amount of photosynthetically active radiation absorbed by the canopy (APAR), and the efficiency with which that energy is transformed in above-ground dry matter (radiation use efficiency, RUE). APAR is the product of incoming photosynthetically active radiation (PAR) and the fraction absorbed by the canopy (fPAR). We estimated fPAR as a non-linear function of MODIS normalized difference vegetation index (NDVI). RUE was empirically estimated for the two principal forage resources of the region, yielding the following relations: ANPP = 0.6 × APAR + 12, (R² = 0.86; p < 0.001; n = 18) for the upland sown pastures, and ANPP = 0.27 × APAR + 26, (R² = 0.74; p < 0.001; n = 18) for the lowland naturalized pastures, with ANPP in g/m²/60 days and APAR in MJ/m²/60 days. The models were able to predict independent ANPP values with acceptable accuracy. Computational procedures were automated and run in a Relational Data Base Manager System that stored and managed all the information. The system is currently monitoring 212,794 ha in 83 farms and provides monthly ANPP values for the previous month and a history of the last 6 years. The data so generated show ANPP differences between the two major forage resources, considerable variability of a given month’s ANPP among years and paddocks, and contrasting among-farm differences in the efficiency of conversion of ANPP and forage supplements into beef production. The system was well accepted by end users who utilize it mainly for making near real time decisions according to last month ANPP, and explaining results of previous production cycles by incorporating ANPP as an explicative variable. However, there were differences among farmers in the degree of utilization, apparently related to the advisor’s attitude toward this new technology. Our results indicate that (1) forage production of large extensions can be monthly monitored at the paddock level by a small laboratory with capabilities in geographic information systems, and (2) advisors and farmers apply this information to their managerial decisions.     

Fluorescence, browning index, and color in infant formulas during storage

Free and total fluorescent compounds, browning index, and color formation were measured in milk-based powdered infant formulas (IF) during 2 years of storage at 20 and 37 degrees C. The excitation spectra from 415 nm emission show three peaks (ex lambda1 = 270 nm, lambda2 = 325/315 nm, lambda3 = 350 nm) and from 347 nm excitation two emission peaks (415 and 520 nm), and no wavelength shifts were observed. Temperature and time of storage exert in general no significant effect on the development of fluorescence emission intensity and browning index. However, an important increase in pentodilysine was recorded-probably because of the iron and ascorbic acid contents of the samples-as well as in browning index in adapted IF. In both IF a color increase (deltaE) throughout storage was observed, this increase being greater in samples stored at 37 degrees C than in those stored at 20 degrees C. The increase in color with time fitted a linear regression model. Color appeared to be an indicator of sufficient sensitivity to measure the effect of temperature or storage time.     

ADVANCES IN DIAGNOSIS OF IRON DEFICIENCY IN AVOCADO

Several methods for determination of extractable iron (Fe; or so-called “active Fe”) have been proposed. In this study, three methods of Fe extraction were tested: 1.5% phenanthroline (pH 3) and 1 M hydrochloric acid (HCl) from fresh leaves, and 1 M HCl from oven-dry leaves. A six-year-old avocado orchard (cultivar ‘Hass’), grown on a calcareous soil in the proximity of Cabildo (Valparaíso region, Chile), was selected for the study. Samples of mature (5–7 moths-old) leaves of different degree of chlorosis were collected. Total Fe concentrations in chlorotic leaves were similar or even greater than in green leaves. Regressions between the extractable Fe concentrations and the leaf SPAD-color were statistically significant for phenanthroline method, while non-significant for HCl methods. Thus, phenanthroline method was superior over others for diagnosis of Fe deficiency in avocado. Phenanthroline-extractable Fe concentration of 6 mg kg^?1 was considered as a critical value for mature avocado leaves.