Growth performance,feed utilization and body composition of Dentex dentex fed on different macronutrient combinations

Determining an adequate macronutrient balance is essential to guarantee the production success. As protein is the limiting component for fish food, the utilization of lipids or carbohydrates as partial substitutes of this nutrient is a challenge to improve its use. In order to get an approximation of the maximum levels of utilization for carbohydrates and/or lipids and determine the most adequate macronutrient to partly replace protein as the main energy source of diets for dentex (91.7 ± 1.4 g mean weight), four experimental diets with different protein:lipid:carbohydrate percentages (43/16/28, 43/24/4, 38/19/28 and 38/24/13) were tested for 13 weeks. The results indicated the possibility of using 38% of dietary protein without affecting growth performance, under the experimental conditions. There were no differences among the four diets either in most of the nutritive utilization indicators or in the body composition and haematological parameters. The influence of dietary composition was only observed in the feed intake, being higher with more dietary carbohydrates, and the hepatosomatic index and protein efficiency ratio, showing more elevated values in diets with a higher lipid level. The dentex capacity of using both carbohydrates and lipids efficiently to obtain the necessary energy for its correct growth, as well as to compensate the energetic ‘vacuum’ caused by the dietary protein reduction, under the assayed conditions, was confirmed.     

Pinger affects fish catch efficiency and damage to bottom gill nets related to bottlenose dolphins

There is some evidence that the presence of Tursiops truncatus in fishing areas represents a real economic threat to fishermen due the dolphin feeding on the entangled fish, damaging the nets and reducing the fish catch. We have carried out experiments to assess the efficiency of a pinger in decreasing the interaction between the dolphins and fishing nets, in a fishing area off the coast of southern Italy, where Tursiops truncatus is frequently observed to interact with bottom gill nets. Two identical monofilament bottom gill nets (900 m long), one equipped with pingers and the other without, were used to measure the effect of these pingers on the abundance of the catch and net damage. For each haul (58 in total), data on dolphin sightings near the nets, damage judged to have been done by dolphins, weight and species composition of the catch were collected. All damage to the nets were recorded at the end of each haul. Dolphins in the fishing area were sighted 11 times out of 29 fishing activities (38%). The net equipped with pingers contained 28% more fish (biomass) than the net without pingers (t test, P < 0.04) and was less damaged (−31%, t test, P < 0.01). To assess whether the efficacy of these pingers remain constant over long period, long-term experiments should be carried out.     

Effect of dietary vitamin A on Senegalese sole (Solea senegalensis) skeletogenesis and larval quality

The effects of different levels of vitamin A (VA) in Senegalese sole larval performance and development were evaluated by means of a dietary dose–response experiment using enriched Artemia metanauplii as a carrier of this micronutrient. Larvae were fed from 6 to 27 days post hatch (dph) with enriched Artemia containing graded levels of total VA (1.3, 2.1, 4.5 and 12.9 µg VA mg^− 1 DW). The content of VA in live prey directly affected its accumulation in larvae and early juveniles. Retinyl palmitate accumulated during larval ontogeny, whereas retinol showed the opposite trend, decreasing from hatching until 41 dph and then remaining constant until the end of the study.In metamorphic larvae (10 and 15 dph), VA did not affect the number of thyroid follicles or the intensity of the immunoreactive staining of T₃ and T₄. However, at older stages of development (post-metamorphic larvae: 20, 30, 41 and 48 dph), VA decreased the number of thyroid follicles but increased their mean size and enhanced T₃ and T₄ immunoreactive staining. A dietary excess of VA did not affect either larval performance in terms of growth and survival or the maturation of the digestive system. However, the most remarkable impact of this morphogenetic nutrient was detected during skeletal morphogenesis. Dietary VA accelerated the intramembranous ossification of vertebral centrums, which led to the formation of a supranumerary haemal vertebra and a high incidence of fused and compressed vertebrae in fish fed 2.1, 4.5 and 12.9 mg VA mg^− 1 DW. In addition, VA also affected those structures from vertebrae and caudal fin formed by chondral ossification, leading to defects in their shape and fusions with adjacent skeletal elements. In particular, the caudal fin was the region most affected by the dietary treatments. In order of importance, the bones with more developmental anomalies were the modified neural and haemal spines, epural, hypurals and parahypural. The impact of systemic factors such as thyroidal hormones in skeletogenesis should not be neglected since present results revealed that an excess of dietary VA affected the levels of T₃ and T₄, which might have affected bone formation and remodelling, leading to skeletal deformities.     

Control of Neofabraea alba by plant volatile compounds and hot water

Fumigation by plant volatile compounds and hot water treatment were tested in vitro and in vivo for their activity against Neofabraea alba (anamorph Phlyctema vagabunda), the cause of lenticel rot in apple fruit. In vitro trials with volatile compounds showed a consistent inhibition of pathogen growth by carvacrol, trans-cinnamaldehyde, citral and trans-2-hexenal, while (?)-carvone, hexanal, p-anisaldehyde, 2-nonanone and eugenol showed progressively lower inhibition. The greatest inhibition of mycelial growth was demonstrated by carvacrol (effective doses for 50 and 95 inhibition [ED₅₀ and ED₉₅] = 5.9 and 17.0 μL L^?1, respectively; minimum inhibitory concentration [MIC] = 36.9 μL L^?1) and of conidial germination by trans-2-hexenal (ED₅₀ and ED₉₅ = 4.1 and 6.9 μL L^?1, respectively; MIC = 9.2 μL L^?1). Hot water showed a complete inhibition of conidial germination in vitro after 10, 2 and 1 min of exposure at 40, 45 and 50 °C, respectively, and a complete inhibition of mycelial growth after 20 min of exposure at 75 °C. Among the volatile compounds tested, only 25 μL L^?1 of carvacrol slightly reduced fungal infection on artificially infected apples (11.4% efficacy). Hot water treatment at 45 °C for 10 min showed high efficacy in the control of lenticel rot on apples. Reduction of infection was 80% in artificially inoculated fruit (cv Golden Delicious) and 90% in naturally infected fruit (cv Pink Lady) after 90 and 135 d of storage, respectively.     

Fruit yield and quality of strawberry plants transformed with a fruit specific strawberry pectate lyase gene

Two transgenic strawberry lines (Pel 1 and Pel 3) containing the open reading frame of a fruit specific strawberry pectate lyase gene (FaplC) under the control of the CaMV35S promoter have been obtained to evaluate the role of this gene on fruit softening. Ripen fruits from both lines showed a significant down-regulation of FaplC, being the percentage of silencing of 84 and 71% on Pel 1 and Pel 3, respectively. The agronomic behaviour of transgenic plants was evaluated during two consecutive years. Fruit set increased in the two transgenic lines when compared with control plants, although Pel 1 showed a significant reduction on fruit weight. Firmness of full ripen fruits from Pel lines was significantly higher than control fruits, while color and soluble solids were not affected. The increase of firmness in Pel lines was maintained when ripe fruits were stored for 3 days at 25 °C. Histological analysis of ripe fruits showed lower intercellular spaces and a higher degree of cell to cell contact area in transgenic fruits when compared with controls. Altogether, these results suggest a direct relationship between pectate lyase gene expression and strawberry fruit softening.     

Identification of proteins related to microspore embryogenesis responsiveness in anther cultures of winter triticale (×<Emphasis Type="Italic">Triticosecale</Emphasis> Wittm.)

For a better understanding of the physiological background of microspore embryogenesis (ME), the protein profile was analyzed in four winter triticale DH lines, which show extremely different embryogenic potential. The analysis were conducted with anthers at the phase of development optimal for ME induction and then after low temperature (LT, 3 weeks at 4 °C) ME-inducing tillers treatment. The sub-proteome of anthers was mapped by two-dimensional gel electrophoresis (2-DE). The protein species significantly more abundant (at least 2-fold) in responsive DH lines after LT treatment were chosen for identification by MALDI-TOF/TOF analysis. In total, 31 protein species were successfully identified as involved in the determination of microspore competence, stress response and in the regulation of ME induction. Microspore competence required sufficient energy supply and efficient system of cell protection that determine survival under prolonged LT stress treatment. LT stress was associated with increased accumulation of proteins typical for cell defence against oxidative stress (e.g., l-ascorbate peroxidase), chaperons (e.g., HSP70) and other enzymes/factors ensuring protein biosynthesis, stability and active cell divisions. Also here, effective cell defence required undisturbed energy supply. Among proteins that accumulated differentially in accordance with microspore embryogenic potential again the most important role seems to be played by the enzymes ensuring energy production and determining ability of plant stress adaptation. Two protein species (enolase, 12S storage protein), proposed earlier as candidates for markers of embryogenesis in other in vitro plant culture systems confirmed their utility for triticale anther cultures.     

Effects of a Fish Oil Rich in Docosahexaenoic Acid on Cardiometabolic Risk Factors and Oxidative Stress in Healthy Rats

Omega-3 polyunsaturated fatty acids are associated with a lower risk of cardiometabolic diseases. However, docosahexaenoic acid (DHA) is easily oxidized, leading to cellular damage. The present study examined the effects of an increased concentration of DHA in fish oil (80% of total fatty acids) on cardiometabolic risk factors and oxidative stress compared to coconut oil, soybean oil, and fish oil containing eicosapentaenoic acid (EPA) and DHA in a balanced ratio. Forty healthy male Sprague–Dawley rats were supplemented with corresponding oil for 10 weeks. Supplementation with the fish oil containing 80% DHA decreased plasma fat, plasma total cholesterol and muscle fat compared to the coconut oil and the soybean oil. Increasing concentrations of DHA induced incorporation of DHA and EPA in cell membranes and tissues along with a decrease in ω-6 arachidonic acid. The increase in DHA promoted lipid peroxidation, protein carbonylation and antioxidant response. Taken together, the increased concentration of DHA in fish oil reduced fat accumulation compared to the coconut oil and the soybean oil. This benefit was accompanied by high lipid peroxidation and subsequent protein carbonylation in plasma and in liver. In our healthy framework, the slightly higher carbonylation found after receiving fish oil containing 80% DHA might be a protecting mechanism, which fit with the general improvement of antioxidant defense observed in those rats.     

Recent progress in the field of N-acylalanines as systemic fungicides

The influence of structural variations in compounds of the N-acylalanine type, on their fungicidal activity towards Peronosporales, was examined. Within a series of methyl N-(acyl)-N-(2,6-xylyl)alaninates ( I ), a quantitative structure-activity relationship was given for the curative action against Plasmopara viticola, through a Hansch-type equation. A deviation from this equation is discussed with reference to benalaxyl ( I ; acyl=phenylacetyl). Syntheses and qualitative indications of activity are reported for structural changes in the xylyl and in the alanine moieties. Progress in the latter approach is briefly outlined.