Feeding trials with hatchery produced white sturgeon juveniles (Acipenser transmontanus)

Growth and survival of white sturgeon larvae were examined at ad libitum feeding with three commercial salmonid diets, and experimental crustacean diet, and a live food control (cubifex). The results demonstrated that some manufactured diets, particularly a semi-moist ration, can be used to rear white sturgeon during the first 40 days of feeding. Although specific growth rates of fish fed a semi-moist feed were 40% lower than those fed live foods, survival rates were similar. The high mortality previously associated with later transfer of fish from live foods to manufactured diets was avoided. Dry diets were not well accepted and resulted in lower rates of growth and survival.     

New perspectives on aquarium fish trade

ABSTRACT:   Since the 1990s, the international market for importing aquarium fish is suspicious of stock coming from South-East Asia. Fish catches are still executed with cyanide-based toxic products. In the present paper, the potential of the French Polynesian Islands to develop a marine aquarium fish business with a new approach is explored. Coral reef fish are captured at the larval stage with crest nets, then larvae are reared in aquaria before being put on the world ornamental fish market. This approach offers several advantages: (i) larvae are captured with a passive system placed on the reef crest (crest net) that does not destroy the environment and limits the stress on collected larvae; (ii) larvae are then put into farmed basins that allow them to be controlled sanitarily; and (iii) larvae are weaned at the farm and fed rapidly with artificial food. This method increases survival rates as it eliminates the food acclimatization problem of fish captured at adult stage (main cause of fish mortality in aquaria). Overall, reared larvae will constitute a new product in terms of species, sizes and quality of ornamental fish on the aquarium market.     

Foaming and Emulsifying Properties of Fractions of Gluten Peptides Obtained by Limited Enzymatic Hydrolysis and Ultrafiltration

Gluten hydrolysates were prepared by limited enzymatic hydrolysis with a protease having a chymotryptic activity in the presence or in the absence of cysteine during the dispersion phase of the process. The hydrolysates were fractionated by ultrafiltration, using two inorganic membranes with different molecular weight cut-off (MWCO), 50 kg/mol and 150 kg/mol. The retentates were enriched in hydrophobic peptides and the permeates were enriched in hydrophilic peptides. The foaming and emulsifying properties of hydrolysates, retentates and permeates were analysed at two pHs (4 and 6·5) and two salt concentrations (0·2 and 2% NaCl). Hydrolysates displayed a foaming capacity, but the foams were not stable. Permeates generated foams at pH 6·5 only, and these foams had a very short life-time. Permeates displayed no emulsifying properties. Retentates yielded foams with a good stability and were more efficient than whole hydrolysates to stabilise emulsions. They provided a strong resistance to coalescence. The functional properties of retentates were only sightly influenced by pH and ionic strength. Neither cysteine addition, which helps gluten dispersion and increases the yield of soluble hydrolysate, nor the MWCO of the ultrafiltration membranes influenced the functionality of the hydrolysate fractions.     

Suitability of two laboratory testing methods to evaluate the side effects of pesticides on Typhlodromus pyri Scheuten (Acari: Phytoseiidae)

BACKGROUND: Laboratory results of the French ANPP/CEB guideline No. 167 and IOBC/WPRS Ring Testing Group methods for testing the side effects of pesticides on the predatory mite Typhlodromus pyri Scheuten were compared with respect to their suitability to evaluate the toxicity of three pesticides. RESULTS: Results obtained with the ANPP/CEB guideline allow the demonstration of significant differences between two slightly toxic products, a dichlofluanid 500 g kg(-1) kWP (Euparen) 50WP) and a quinoxyfen 250 g L(-1) SCC (Legend), and a highly toxic cymoxanil 60/mancozeb 200/folpet 275 g kg(-1) WP [Remiltine F Pepite) (RFP)], on the basis of bioassays conducted in the laboratory. In contrast, results obtained with the IOBC/WPRS method classified all three as harmful.CONCLUSION: The evaluation of the toxicity of RFP revealed that the concentration, the quantity of the wet deposit and the food source used in the IOBC/WPRS method maximise the toxicity, in comparison with those used in the ANPP/CEB protocol. Valid criteria in controls were all respected in the ANPP/CEB tests but not in the IOBC/WPRS samples. This result revealed difficulties related to the use of the IOBC/WPRS method in laboratories.     

Solubilization of chitosan by bipolar membrane electroacidification

Chitosan, a partially deacetylated derivative of chitin, was solubilized by bipolar membrane electroacidification (BMEA). Bipolar/monopolar (anionic or cationic) configuration and chitosan addition mode (single step or stepwise) were examined. Chitosan solubility and electroacidification parameters were monitored during the process to determine the optimal conditions. Bipolar/anionic configuration and stepwise feeding mode led to chitosan solubilization yield of 91% in 60 min at 20 mA/cm(2). In this configuration, chitosan solution had a pH of 2.5, a conductivity of 8.5 mS/cm, and an ash content of 0.2%. Relative energy consumption was 0.05 kWh/L of 1% chitosan solution prepared. Although some chitosan particles were aggregated in the electrodialysis stack, limiting chitosan solubilization, BMEA allowed complete solubilization of chitosan circulating in the system.     

Effects of ramipril on renal function during progressive overpacing-induced heart failure in dogs

OBJECTIVE: To investigate the effects of preventive angiotensin converting enzyme inhibitor treatment with ramipril in dogs with progressively severe experimentally induced heart failure. ANIMALS: 20 dogs. PROCEDURES: Dogs were randomly allocated to receive no treatment (control) or ramipril (0.125 mg/kg, PO, daily) for 7 weeks. Physical examination, repetitive catheterization of the right side of the heart, and echocardiography were performed before the study (day 0) and weekly for 7 weeks. Renal plasma flow (RPF) as determined by para-aminohippuric acid clearance and glomerular filtration rate (GFR) as determined by creatinine and iohexol clearances were measured on day 0 and at weeks 4 and 7. RESULTS: Overpacing induced a progressive increase in right atrial pressure (RAP) and pulmonary artery pressure, occluded (PAPO), with a decrease in systemic arterial pressure. There were progressive alterations of echocardiographic indices of diastolic and systolic ventricular function. The RPF and GFR decreased before cardiac output decreased, and filtration fraction increased. The logarithm of the urinary sodium-to-potassium concentration ratio (log(10)[Na(+)/K(+)]) decreased. Significant effects of ramipril included a delay in clinical signs of heart failure, a late decrease in RAP and PAPO, and increases in the sodium excretion fraction and log(10)(Na(+)/K(+)). There was a satisfactory agreement between the creatinine and iohexol clearance measurements. Conclusions AND CLINICAL RELEVANCE: Results suggest that, in this rapid-evolving, dilated cardiomyopathy, activation of the renin-angiotensin system contributes to the pathophysiology of heart failure late in the disease and essentially by an activation of renal salt and water retention.     

Translating the terrestrial mitigation hierarchy to marine megafauna by‐catch

In terrestrial and coastal systems, the mitigation hierarchy is widely and increasingly used to guide actions to ensure that no net loss of biodiversity ensues from development. We develop a conceptual model which applies this approach to the mitigation of marine megafauna by‐catch in fisheries, going from defining an overarching goal with an associated quantitative target, through avoidance, minimization, remediation to offsetting. We demonstrate the framework's utility as a tool for structuring thinking and exposing uncertainties. We draw comparisons between debates ongoing in terrestrial situations and in by‐catch mitigation, to show how insights from each could inform the other; these are the hierarchical nature of mitigation, out‐of‐kind offsets, research as an offset, incentivizing implementation of mitigation measures, societal limits and uncertainty. We explore how economic incentives could be used throughout the hierarchy to improve the achievement of by‐catch goals. We conclude by highlighting the importance of clear agreed goals, of thinking beyond single species and individual jurisdictions to account for complex interactions and policy leakage, of taking uncertainty explicitly into account and of thinking creatively about approaches to by‐catch mitigation in order to improve outcomes for conservation and fishers. We suggest that the framework set out here could be helpful in supporting efforts to improve by‐catch mitigation efforts and highlight the need for a full empirical application to substantiate this.     

Seroprevalence of Neospora caninum antibodies and its consequences for reproductive parameters in dairy cows from Dakar–Senegal,West Africa

The aim of this study was to determine the seroprevalence of Neospora caninum antibodies and its effects on reproductive parameters in cows in intensive dairy herds in Dakar. Randomised blood samples were taken for serology from 196 cows in four herds with a history of sporadic abortion. All of the sera were assayed for antibodies against N. caninum, Candida guillermondii, Coxiella burnetii, and Chlamydophila sp. The associations between serostatus and reproductive parameters (abortion, number of inseminations to conception, and calving to conception interval) were assessed over a period of 5 years (2004–2008). The seroprevalence of N. caninum antibodies in dairy cattle was 17.9%. The local Gobra breed and crossbreeds had higher levels of N. caninum antibodies than exotic breeds (p < 0.05). For the most recent pregnancies, seropositive cows required more inseminations to establish conception than seronegative cows (p < 0.05). The results indicate that dairy cattle from Dakar are exposed to N. caninum. Neosporosis should, therefore, be systematically considered as a cause when the calving to conception interval is prolonged.     

<Emphasis Type="Italic">In planta</Emphasis> PCR-based detection of early infection of plant-parasitic nematodes in the roots: a step towards the understanding of infection and plant defence

The polyphagous obligate parasites Meloidogyne spp. devastate a wide range of crop plants including bananas and plantains. Their infestations impact agriculture worldwide. Therefore, an effective combating regime against this nematode species and an in-depth understanding of plant-nematode interaction are essential. Early detection of infection by visual inspection is not possible. This hampers early control strategy efforts and makes in-depth research of the early infection and plant defence unfeasible. A simple and robust in planta PCR-based nematode detection method is described here as the first crucial step. This PCR-based detection assay exploits the existence of the Internal Transcribed Spacer 1 (ITS 1) region of the ribosomal DNA (rDNA) gene family in the nematodes for early detection of nematode penetration into the roots. The results demonstrate that this detection assay is suitable to serve as a molecular screening tool for plant root diagnostic purposes.