Effects of additive iron on growth,tissue distribution,haematology and immunology of gilthead sea bream, <Emphasis Type="Italic">Sparus aurata</Emphasis>

The comparative effects of iron-supplemented levels on growth, tissue distribution, haematology and immunology of gilthead sea bream, Sparus aurata (2 g) were investigated, using four organic (50, 100, 200, 300 mg ORG/kg diet) and one inorganic iron source (200 INOR mg/kg diet). Fish were treated for 12 weeks with the experimental diets and maintained at a water temperature of 19–22°C. Growth (final weight and specific growth rate), tissue distribution (spleen, liver and muscle), haematological parameters (red blood cells, haematocrit, haemoglobin and mean corpuscular haemoglobin concentration) and non-specific immune indexes (respiratory burst activity and antibacterial activity of serum) were analysed. No significant differences were found in growth and iron tissue distribution among the tested groups. Red blood cell counting was statistically higher in fish given 50 ORG, 100 ORG, 200 ORG and 200 INOR feeds. However, haematocrit, haemoglobin and mean corpuscular haemoglobin concentration were not significantly affected by increasing dietary iron. Fish receiving the 100 ORG diet had the best performance with respect to the respiratory burst activity and significantly higher values for antibacterial activity of serum were obtained in fish fed with the 300 ORG diet. The present findings provided no clear evidence of the optimum iron concentration. However, there was adequate indication that iron supplementation enhanced the performance of gilthead sea bream, mainly from a haematological and immunological point of view.     

Effects of aromatase inhibitors on reproduction in male three-spined sticklebacks, Gasterosteus aculeatus, exposed to long and short photoperiods

Three-spined stickleback Gasterosteus aculeatus, males were implanted with Silastic capsules filled with different aromatase inhibitors; 1,4,6-androstatriene-3,17-dione or the non-steroidal CGS16949 A, 4-(5,6,7,8-tetrahydrimidazol [1,5-a]pyridin-5-yl) benzonitrile monohydrochloride or empty capsules. The fish were then exposed to long or short photoperiod. Under the long photoperiod most fish in all treatments displayed a hypertrophied kidney (a secondary sexual character in sticklebacks) and completed, quiescent spermatogenesis, similar as in the natural spawning period. Under the short photoperiod the controls had unstimulated kidneys and an active spermatogenesis, whereas the males implanted with both aromatase inhibitors had stimulated kidneys, though not to the extent as in the long photoperiod, and completed, quiescent spermatogenesis. These findings suggest that aromatization is of importance for the inhibitory effects of short photoperiod on reproduction in the stickleback. This revised version was published online in July 2006 with corrections to the Cover Date.     

Residues of six pesticides in fresh peach—nectarine fruits after preharvest treatment

One of the key features of the new cultural systems is the control of harmful agents with environment-friendly methods. In this study, the residue levels of chlorothalonil, iprodione, bupirimate, pirimicarb, chlorpyrifos and fenoxycarb in different peach??nectarine cultivars were investigated. It was found that, with the exception of chlorpyrifos, the residue levels of all pesticides were lower than the Maximum Residues Limits (MRLs) in all peach??nectarine cultivars used. The detected levels of chlorpyrifos were higher than the MRLs in the cultivar ??Maria Bianca?? 7?days after application, but in cv. ??Legory Hkcb?? dropped to very low levels 27?days after application. The degradation over time of the above pesticides in fruits was investigated in the peach cv. ??Andross??. The detected residue levels of bupirimate, iprodione, fenoxycarb, chlorpyrifos and pirimicarb in this peach cultivar were much lower than those recommended by the European Union (MRLs) 33, 22, 22, 28, and 63?days, respectively, after application, whereas the residue levels of chlorothalonil were below the limit of detection by the analytical method used. All pesticides showed a reduction over time. When examining the levels of residues of pirimicarb and chlorpyrifos in peaches (cv. ??Andross??) sampled from different parts of the tree canopy, no significant difference was found between samples collected from the top and the middle parts of the canopy; however, residues of pirimicarb were significantly higher in samples collected at the bottom of the canopy. Overall, the pesticide regime gave residue levels much lower than those of MRLs, in all peach??nectarine cultivars. This use of chemicals is in accordance with features of the new cultural systems to produce fruits with no or minimal pesticide residues, in contrast to the conventional system in which pesticide residues are not considered. Attention should however be paid to chlorpyrifos which should be applied at least 27?days before harvest. Factors related to the cultivars and the position of fruits in the tree canopy should be considered when sampling fruits for pesticide residues analysis.     

Effects of long-term feed deprivation on body weight loss,muscle composition,plasma metabolites,and intermediate metabolism of meagre (<Emphasis Type="Italic">Argyrosomus regius</Emphasis>) under different water temperatures

The effect of feed deprivation at four water temperatures (17, 20, 23, 26 °C) was investigated in meagre (Argyrosomus regius) of initial mean weight ± SD, 116.16?±?4.74 g, in triplicate groups. Fish were deprived of feed for a period of 60 days and sampled on days 0, 14, 41, and 60, during which body weight, specific growth rate, somatic indices, muscle proximate composition, plasma metabolite levels (total lipids, proteins, cholesterol, triglycerides, glucose), and liver and muscle enzymatic activities [L-lactate dehydrogenase (L-LDH), citrate synthase (CS), malate dehydrogenase (MDH)] were evaluated. Long-term feed deprivation resulted in a significant decrease in body weight, condition factor (CF), hepatosomatic index (HSI), muscle lipids, and plasma metabolites (all except proteins) and increase in muscle moisture. Plasma glucose concentration decreased with time and became significantly lower at 41 and 60 days. Glucose concentration and weight loss expressed a different response in the short term (14 days) than in the long term (14 and 60 days) of feed deprivation, suggesting a change in glucose metabolic profile. After 60 days of feed deprivation, there was an increase in the L-LDH activity in the liver at all temperature levels, which reflects a rising glycolytic potential by activating the carbohydrate metabolism and an ATP-dependent demand. MDH activity increased in the liver and muscle, except at 17 °C in the muscle, which indicates aerobic glycolysis and lipolysis. CS activity in the liver increased after the 60 days, whereas that in the muscle decreased, indicating the muscle is less dependent on aerobic oxidation for energy reserves.     

Environmental analysis by on-line immunoextraction and reversed-phase liquid chromatography: optimization of the immunoextraction/RPLC interface

The use of antibodies in HPLC columns for on-line immunoextraction combined with reversed-phase liquid chromatography (RPLC) is of growing interest in environmental and agricultural analysis. This technique is typically performed by using a small RPLC precolumn to capture and concentrate analytes as they elute from the immunoextraction column; however, there is little information on the conditions required for optimizing this interface. This study examined the behavior of this interface by using 2,4-dichlorophenoxyacetic acid (2,4-D) and related herbicides as model analytes. It was found that analyte dissociation from immunoextraction columns followed first-order decay and that the elution of these analytes through the immunoextraction/RPLC interface gave an exponentially modified Gaussian profile. Computer simulations were used to see how analyte elution through the interface changed with different dissociation and retention conditions. Several guidelines were developed from this work that could be used for developing and optimizing on-line immunoextraction/RPLC systems for other chemicals of environmental or agricultural interest.     

The effect of insect meal as a feed ingredient on survival,growth, and metabolic and antioxidant response of juvenile prawn Palaemon adspersus (Rathke, 1837)

For successful prawn aquaculture, feeds should be based on readily consumed ingredients that promote survival and optimal growth performance. This pilot study investigates the rearing of juvenile Baltic prawn Palaemon adspersus. Two feeding trials were carried out for 60 days; both incorporated insect meals, the first one in fishmeal‐based diets, whereas the second one in plant meal ones. Insect meals derived from larvae of Tenebrio molitor (TM), Hermetia illucens (HI) and Musca domestica (MD) were tested as feed ingredients. This study indicated that the inclusion of HI in fishmeal diets resulted in significantly higher growth performance and survival of the prawns, whereas the MD diet led to similarly high growth performance reducing significantly their survival. Growth performance was not affected by the insect inclusion in the plant‐based diets, but survival was higher in the TM and HI inclusion diets. The inclusion of TM and HI resulted in higher protein and energy content of the prawns’ muscle when incorporated in fishmeal and plant meal diets respectively. No significant differences were observed in the activities of hepatopancreas’ amino acid‐catabolizing enzymes. Concluding, the combinations fishmeal–HI and plant meal–TM can be used for the successful rearing of Baltic prawn.     

Antithrombotic lipid minor constituents from vegetable oils. Comparison between olive oils and others

Many epidemiological studies suggest that vegetable oils and especially olive oil present a protective effect against atherosclerosis. In this study, total lipids (TL) of Greek olive oils and seed oils of four kinds, namely, soybean, corn, sunflower, and sesame oil, were separated into total polar lipids (TPL) and total neutral lipids (TNL) via a novel extraction procedure. TPL and TNL of olive oil were fractionated by HPLC for further study. Each lipid fraction from HPLC separation along with TL, TPL, and TNL lipid samples from oils were tested in vitro for their capacity to induce or to inhibit washed rabbit platelet aggregation. Comparison between olive and seed oils supports the superiority of olive oil as high levels of platelet activating factor (PAF) antagonists have been detected, mainly in TPL. In addition, the structure of the most active fraction from olive oil was elucidated, as a glycerol-glycolipid. Because it has already been reported that PAF plays a pivotal role in atherogenesis, the existence of PAF agonists and antagonists in vegetable oils may explain their protective role against atherosclerosis.     

First record of Dryocosmus kuriphilus in Greece

After the first introduction of chestnut gall wasp, Dryocosmus kuriphilus, in Italy, it has spread rapidly in several other European countries, probably largely due to trade in chestnut plants. Despite the measures taken to prevent further spread of this pest to other countries, D. kuriphilus was detected in Greece for the first time in 2014. However, surveys have shown that the pest is still of very limited distribution in Greece. Having faced the damage caused by chestnut blight (Cryphonectria parasitica) over the last 50 years, the production of chestnuts in Greece is now seriously threatened by chestnut gall wasp, which has already caused extensive losses in chestnut production of other countries. In order to minimize the impact of chestnut gall wasp, control measures are being designed involving the release of the parasitoid Torymus sinensis.     

A fish kill at the Aposelemis dam (Crete,Greece) caused by heavy parasitism by Ichthyobodo sp.

A fish kill was recorded at the Aposelemis Dam, which is the main reservoir of drinking water for the island of Crete in Greece. Hundreds of goldfish were found dead at a side stream which provides water to the reservoir. The affected fish had been entrapped in a small pond at the side of the stream with practically zero water renewal as the event occurred in August which is a dry season for the island of Crete. The event was alarming for the local community since anthropogenic pollution was initially suspected which could pose a significant human health threat. Following examination of the fish, the mortality was attributed to heavy infection by the parasitic flagellate, Ichthyobodo sp., whilst no pollutants were detected. The parasite was studied through light and scanning electron microscopy and was identified molecularly.     

Effects of Fish Meal Replacement by a Soybean Protein on Growth,Histology, Selected Immune and Oxidative Status Markers of Gilthead Sea Bream,Sparus aurata

The purpose of the trial was to study the impact of a 6‐mo dietary administration of soybean protein on growth, liver and intestine morphology, immune response, and oxidative stress in gilthead sea bream. The immune response was evaluated by performing immunological assays in blood, head kidney (HK), or serum (respiratory burst activity [RBA], myeloperoxidase content and bacteriolytic activity) and gene expression analysis of immune‐associated genes (MHCIIα [major histocompatibility complex IIα], β2m [β‐2‐microglobulin], CSF‐1R [colony‐stimulating factor‐1 receptor], NCCRP‐1 [nonspecific cytotoxic cell receptor protein 1], TGF‐β1 [transforming growth factor beta‐1], and HSP70 [heat‐shock protein 70]) in HK and intestine. Oxidative stress was evaluated by measuring the activity of liver enzymes associated with antioxidant system. The soybean protein was administrated in the diets at 20, 40, and 60% levels and its effects were evaluated compared with a fish meal diet. Growth and feed efficiency were affected negatively from 40% level. Increased RBA and expression levels of TGF‐β1 and β2m were found in HK only at 40% level. In intestine, at 60% level CSF‐1R expression was upregulated and some signs of inflammation were evident. In liver, at 60% level lipid accumulation in hepatocytes was observed and enzyme activity was increased. Dietary administration of soybean protein indicated changes from 40% in growth and immune response, and exerted an antioxidative effect at 60% level.