Morpho‐demographic traits of two maërl‐forming algae in beds with different depths and fishing histories

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Improving weaning strategies for Senegalese sole: effects of body weight and digestive capacity

To optimize Senegalese sole‐weaning strategies, three experiments were performed. The first trial tested four weaning strategies with a 10 mg sole. Artemia‐fed sole grew threefold less than fish fed an inert diet. Sudden weaning (abrupt change from Artemia to inert diet) and weaning with co‐feeding produced larger sole than did a late weaning treatment; delayed weaning negatively affected fish growth. In the second experiment, the digestive capacity of early‐weaned 1, 2 and 4 mg sole was investigated. The highest growth was observed in sole weaned at 4 mg. Digestive enzyme profiles suggest that sole have an adaptation period to inert diets, with reduced feed intake. This adaptation period is inversely proportional to post‐larvae weight. The third experiment examined weaning with co‐feeding at different weights (2, 5 and 11 mg). These studies demonstrate that sole of 5–10 mg can be weaned, with high survival rates. On the basis of the digestive enzyme profiles, the early introduction of inert diets in co‐feeding with Artemia seems to affect intestinal processes in smaller postlarvae. This study also suggests that trypsin and alkaline phosphatase may be used as indicators of nutritional status in sole of <5 mg.     

Growth,tissue metabolites and digestive functionality in Sparus aurata juveniles fed different levels of macroalgae,Gracilaria cornea and Ulva rigida

The aim of this study was to evaluate the inclusion of two macroalgae as dietary ingredients on growth, body composition, intermediate metabolism, intestinal enzymes and gut histology of Sparus aurata juveniles. Six isocaloric and isonitrogenous diets incorporating 5%, 15% or 25% of Gracilaria cornea or Ulva rigida meal were tested against a control diet. Duplicate groups of fifteen fish (14 g) were fed the experimental diets for 70 days. Growth performance showed an inverse linear relationship with the inclusion level of Gracilaria. Feed conversion ratio increased significantly in fish fed 25% Gracilaria. Ulva presented a quadratic relationship with the lowest SGR at 15% of inclusion. Fish fed 25% Ulva exhibited significantly lower lipid content than those fed control diet. Overall, metabolites did not show differences with specimens fed control diet, except for plasmatic glucose and muscle lactate. Intestinal proteolytic activity was reduced with the macroalgae inclusion level, but all fish showed the same enzyme pattern. The histological study revealed no negative effect on liver and intestine structure by the macroalgae inclusion. The present work demonstrated that these ingredients can be used in practical diets for sea bream, but a more comprehensive research is needed to determine the optimum dietary level in a longer feeding trial.     

Screening for frost tolerance in wheat using the expression of dehydrine genes Wcs120 and Wdhn13 at 17°C

Cold induces expression of Cor/Lea genes, in particular of Wcs120 and Wdhn13 . The level of the expression at low temperatures was related to the frost tolerance (FT) of wheat cultivars. We studied the expression in five cultivars very different in the FT, at relatively high temperature of 17 and 25°C, respectively. Significant correlations at the 1% level were found at 17°C between the expression level and FT, characterized by correlation coefficients 0.92** and 0.97** for Wcs120 and Wdhn13 , respectively. These preliminary results could be used for screening of frost tolerant lines.     

Mortality impact of recreational angling techniques and hook types on Trachynotus ovatus (Linnaeus, 1758) following catch-and-release

We evaluated the post-release mortality (PRM) following catch-and-release in Trachynotus ovatus, one of the main target species of north-western Mediterranean recreational fisheries. In this study, we observed the line-caught fish for 10 d in a holding tank in order to investigate the independence and impact on mortality of several explanatory variables, including fish size, surface temperature, anatomical hooking location, bleeding, hook type, and line cutting. We observed a total PRM of 24.1% and the most important mortality factor by far was the anatomical position of the hook. Anatomically deeper hooking events were highly correlated with fish size and the presence of blood during hooking injuries. The PRM obtained in this study was higher than values reported in previous studies of this species, mainly because we considered the effects of passive angling techniques. Passive angling increased the incidence of deep hooking and consequently increased mortality compared to active angling. This technique also led to an increase in deep hooking by circle hooks. Therefore, we recommend that active angling techniques be encouraged and we emphasize the need for education on the correct use of circle hooks. This study provides guidelines to managers, scientists, and anglers that will promote sustainable development of the recreational fisheries of the Mediterranean.     

Tomography of reaction-diffusion microemulsions reveals three-dimensional Turing patterns

Spatially periodic, temporally stationary patterns that emerge from instability of a homogeneous steady state were proposed by Alan Turing in 1952 as a mechanism for morphogenesis in living systems and have attracted increasing attention in biology, chemistry, and physics. Patterns found to date have been confined to one or two spatial dimensions. We used tomography to study the Belousov-Zhabotinsky reaction in a microemulsion in which the polar reactants are confined to aqueous nanodroplets much smaller than the scale of the stationary patterns. We demonstrate the existence of Turing patterns that can exist only in three dimensions, including curved surfaces, hexagonally packed cylinders, spots, and labyrinthine and lamellar patterns.     

The role of silicon fertilization in the synthesis of phenolic compounds on chestnut plants infected with P. cinnamomi and C. parasitica

Journal of Plant Diseases and Protection - Silicon is considered a beneficial nutrient for agricultural crops by conferred protection against diseases. The antifungal effect of the phenolic...     

Variability Among Maize (Zea mays L.) Inbred Lines for Seed Longevity

Genotypes conserved in active collections may suffer genetic erosion and modifications. The objective of this work was to investigate changes in germination and vigour in maize (Zea mays L.) inbred lines during cold storage in an active collection. Seeds of 16 maize inbreds produced along 16 years were evaluated for emergence and seedling vigour in a growth chamber. Linear and quadratic regressions of vigour and viability-related traits over seed age were calculated and tested for homogeneity. The seed of five production years of five inbreds that behaved differently in the regression analysis was multiplied in 1998, and original and renewed seed were evaluated in a growth chamber in 1999. Viability and vigour decreased linearly with age for most inbreds, particularly for B84 and EP10, varied at random for a few inbreds, and remained high for EP56 and A295. Aging caused reduction of vigour and loss of viability in most inbreds. There was variability for seed longevity among inbred lines; longevity was highest for inbred EP56. During storage, some seeds of each inbred died, while enduring seeds, when multiplied, produced new seed with enhanced viability and vigour compared to the average seed of the inbred, suggesting natural selection for viability and vigour during storage within inbred lines.