Effects of biofloc technology on reproduction and ovarian recrudescence in Nile tilapia

The objectives of this study were to evaluate the reproductive cycle, morphological changes of ovary and mobilization of energy reserves in Nile tilapia reared with biofloc technology (BFT). In general, the growth and reproductive performance were highly similar between BFT and Control system (clear water). Difference between the systems was found in the hepatosomatic index (using mixed‐effects models), which suggested that BFT can alter the energy mobilization in the post‐spawning period. The absolute and relative fecundity, fertilization rate, number of larvae produced per female, gonadosomatic index, proportion of oogenesis cells, number of post‐ovulatory and atretic follicles were similar between the two systems. We also did not detect a reduction in the reproductive cycle length in Nile tilapia reared in BFT. Because there was no evidence of the negative effects of BFT on Nile tilapia reproduction, we concluded that BFT might be used for breeder stocking of this species.     

Improving the estimation of soil water evaporation based on days after wetting

Soil evaporation constitutes a major pathway of water loss in agriculture. Understanding its dynamics in the face of drying and soil cover is fundamental to improve both simulation models and the sustainability of production systems. Thus, the objective of this study was to estimate soil evaporation as a function of drying and percentage of soil cover. Three experiments were carried out in three different periods. In each of the periods, in parallel and in an adjacent area, an experiment was carried out to evaluate the influence of weighing micro-lysimeter (ML) height on the estimation of direct soil evaporation. The experiments were installed with a completely randomized design. For the experiments that measured evaporation as a function of cover, the treatments consisted of six different percentages of cover of the internal area of the ML (0%, 10%, 25%, 50%, 75% and 100%), with four replicates, using artificial plants to cover the soil. The experiments that estimated evaporation as a function of ML height were conducted with eight repetitions and three different ML heights (100, 200 and 300 mm). It was observed that the accumulated evaporation up to 25 days after wetting was 52% and 53% lower in micro-lysimeters with 100 mm height, compared to those with 200 and 300 mm height, respectively, for all experiments. The new model developed to calculate soil evaporation as a function of the days after wetting and percentage of soil cover showed excellent performance (NSE > 0.95).     

Estimating symbiotic N2 fixation in Robinia pseudoacacia

Estimating symbiotic di‐nitrogen (N₂) fixation is challenging, especially when working with woody N₂ fixers in field trials. Fortunately, isotope methods based on ¹⁵N natural abundance or on ¹⁵N artificial enrichment (dilution method) make it possible to estimate the proportion of nitrogen derived from the atmosphere (Ndfa) in N₂‐fixing species. These methods have been extensively used in the field for herbaceous species, much less for tree species such as alder and acacia, and rarely for black locust (Robinia pseudoacacia). The objectives of this study were to characterize the fixation potential of black locust in a plantation by using the two ¹⁵N isotope methods in the field, and to document values of isotope fractionation occurring during N₂ fixation (the B value). B values were estimated both by growing trees on an N‐free medium in controlled conditions (B_lab) and by making Ndfa calculated with the natural abundance method converge with Ndfa calculated with the ¹⁵N dilution method in the field (B_field). The two methods gave consistent estimates of the B value. B values ranging between –1.4 and –3.2‰ were found, varying with the age of the plant material. Up to 76% of the N in the black locust trees came from the atmosphere, representing more than 45 kg N ha^?1 over five years and confirming that black locust may be well adapted to N‐poor soils.     

Heparanase and Syndecan-4 Are Involved in Low Molecular Weight Fucoidan-Induced Angiogenesis

Induction of angiogenesis is a potential treatment for chronic ischemia. Low molecular weight fucoidan (LMWF), the sulfated polysaccharide from brown seaweeds, has been shown to promote revascularization in a rat limb ischemia, increasing angiogenesis in vivo. We investigated the potential role of two heparan sulfate (HS) metabolism enzymes, exostosin-2 (EXT2) and heparanase (HPSE), and of two HS-membrane proteoglycans, syndecan-1 and -4 (SDC-1 and SDC-4), in LMWF induced angiogenesis. Our results showed that LMWF increases human vascular endothelial cell (HUVEC) migration and angiogenesis in vitro. We report that the expression and activity of the HS-degrading HPSE was increased after LMWF treatment. The phenotypic tests of LMWF-treated and EXT2- or HPSE-siRNA-transfected cells indicated that EXT2 or HPSE expression significantly affect the proangiogenic potential of LMWF. In addition, LMWF increased SDC-1, but decreased SDC-4 expressions. The effect of LMWF depends on SDC-4 expression. Silencing EXT2 or HPSE leads to an increased expression of SDC-4, providing the evidence that EXT2 and HPSE regulate the SDC-4 expression. Altogether, these data indicate that EXT2, HPSE, and SDC-4 are involved in the proangiogenic effects of LMWF, suggesting that the HS metabolism changes linked to LMWF-induced angiogenesis offer the opportunity for new therapeutic strategies of ischemic diseases.     

Milk secretion of nitrofurantoin,as a specific BCRP/ABCG2 substrate,in assaf sheep: modulation by isoflavones1

Studies on residues in milk used for human consumption have increased due to health concerns and priority interest in the control of potentially risky drugs. The protein BCRP/ABCG2, present in the mammary epithelia, actively extrudes drugs into milk and can be modulated by isoflavones. Nitrofurantoin is a specific BCRP substrate which is actively excreted into milk by this transporter. In this research, we studied nitrofurantoin transport into milk in four experimental groups: G1‐calves fed forage with isoflavones; G2‐calves fed forage with isoflavones and administered exogenous genistein and daidzein; G3‐calves fed forage without isoflavones; G4‐calves fed forage without isoflavones and administered exogenous genistein and daidzein. Results show increased levels of nitrofurantoin in milk from calves without isoflavones (G3) and decreased nitrofurantoin residues in milk when isoflavones were present, either by forage (G1 and G2) or by exogenous administration (G4). The values of C_max in milk were significantly lower in those groups with isoflavones in forage (G1, G2). Plasma levels were low and unmodified among the groups. Inter‐individual variation was high. All these results seem to point to a feasible control of drug secretion into milk through isoflavones in the diet when the drug is a good BCRP/ABCG2 substrate.     

Fiscal Decentralization and Economic Growth in Central and Eastern Europe

The majority of the literature on fiscal decentralization has tended to stress that the greater capacity of decentralized governments to tailor policies to local preferences and to be innovative in the provision of policies and public services, the greater the potential for economic efficiency and growth. There is, however, little empirical evidence to substantiate this claim. In this paper we examine, using a panel data approach with dynamic effects, the relationship between the level of fiscal decentralization and economic growth rates across 16 Central and Eastern European countries over the 1990–2004 period. Our findings suggest that, contrary to the majority view, there is a significant negative relationship between two out of three fiscal decentralization indicators included in the analysis and economic growth. However, the use of different time lags allows us to nuance this negative view and show that long‐term effects vary depending on the type of decentralization undertaken in each of the countries considered. While expenditure at and transfers to sub‐national tiers of government are negatively correlated with economic growth, taxes assigned at the sub‐national level evolve from having a significantly negative to a significantly positive correlation with the national growth rate. This supports the view that sub‐national governments with their own revenue source respond better to local demands and promote greater economic efficiency     

Model‐based assessment of local‐scale fish larval connectivity in a network of marine protected areas

We assessed by numerical modeling the coastal fish larval dispersion along the southern coast of Mallorca (Balearic Islands, NW Mediterranean) with the objective of determining the factors that contribute to successful recruitment. We assumed that fish larvae dispersal is mainly regulated by physical transport. Currents are mainly wind driven in this area; therefore, changes in wind forcing have a first‐order impact on larval transport. The synoptic wind patterns were systematically analyzed based on self‐organizing map analysis. The wind fields were clustered using a neural network pattern recognition approach into two modes, producing opposite along‐shelf flow. The seasonal changes between spring and summer in the dominance of either mode modulate the along‐shelf circulation, producing flow shifts under some circumstances. This variability in the wind regime was consistent throughout the 10 years analyzed (2000–2009). Using the Princeton Ocean Model (POM) and a particle‐tracking algorithm, we analyzed the effect of wind‐forced currents in the connectivity among near‐shore habitats. We show that, at the spatial scale considered, the coastal morphology and stochastic wind forcing favor local recruitment (mean of 30% self‐recruitment). Maximum transport distances of 20–30 km were typically associated with particles left to drift for 21 days. The implications for the performance of the four marine protected areas near SW Mallorca Island are discussed. Our results suggest that, although wind episodes determine the fate of short‐time spawning events, on a seasonal basis, regular larval supply to coastal zones is ensured by wind stochasticity.     

The effects of the dietary biotin on zebrafish Danio rerio reproduction

An experiment was conducted to investigate the effects of dietary biotin on zebrafish Danio rerio reproduction. Biotin and avidin (biotin antagonist) were added to two isonitrogenous and isocaloric purified diets to provide molar avidin:biotin ratios of 0:1 (biotin‐sufficient diet) and 120:0 (biotin‐unsufficient diet). Each diet was fed to a group of males mean initial mass 0.262 g) and a group of females (mean initial mass 0.285 g) for 99 days. Following this feeding period, males fed biotin‐sufficient diet exhibited higher gonado‐somatic index, sperm density, sperm motility and sperm viability than those fed biotin‐unsufficient diet (P < 0.05). In the presence of biotin‐sufficient males, biotin‐sufficient females spawned more eggs (222.2 eggs) than biotin‐deficient females (18.8 eggs) (P < 0.05). The same pattern was observed with biotin‐deficient males (7.6 vs. 1.8 eggs) (P < 0.05). Biotin‐sufficient males generated a higher percentage of fertilized eggs (90% vs. 42%), hatching rate (62% vs. 27%), larvae survival (98% vs. 37%) and larvae length at 7 days post fertilization (4.4 mm vs. 4.2 mm) than biotin‐deficient males (P < 0.05) . Biotin status of the male is of high consideration for successful breeding in zebrafish, because it significantly impacts the reproductive performances of the female.     

Validation of a thermal threshold nociceptive model in bearded dragons (Pogona vitticeps)

Objectives

To validate a thermal threshold (TT) nociceptive model in bearded dragons (Pogona vitticeps) and to document TT changes after administration of morphine.