Research highlights ► EDs impair body weight. ► In the hypothalamus several peptidergic hormones and neurotransmitters controlling feeding behaviour are impaired by EDs. ► EDs derange lipid ...metabolism by targeting key metabolic sensors. ► The phthalate DEHP at low doses triggers lipid synthesis and decreases food intake stimulus.
The aim of this study was to evaluate the potential use of the harpacticoid copepod Tisbe spp as prey in Amphiprion clarkii larviculture. After hatching, A. clarkii larvae were divided in four ...experimental groups for feeding studies as follows: group A (control group) fed rotifers (Brachionus plicatilis) followed by Artemia nauplii; group B fed a mixed diet of rotifers and Tisbe spp nauplii followed by a combination of A. nauplii and Tisbe spp copepodites/copepods; group C fed copepod nauplii solely followed by Tisbe spp copepodites and copepods; group D fed rotifers followed by Tisbe spp copepodites and copepods. In this study we observed a positive effect of feeding Tisbe spp copepods in A. clarkii larviculture as a supplement live food to the traditional diet based on rotifers and A. nauplii. In group B larvae, fed a combination of rotifers/Tisbe spp nauplii followed by a combination of A. nauplii/Tisbe spp copepodites-adults, a significant increase of IGF II and IGF I gene expression and a significant decrease of myostatin gene expression was evidenced by Real Time PCR compared to the other experimental groups. In this same group we also observed the best results in terms of growth (total length and weight) and survival.
In conclusion, the harpacticoid copepod Tisbe spp may be considered a suitable live prey for marine fish larvae larviculture when used as a supplement to the traditional diet based on rotifers and A. nauplii.
A multi‐technique approach was used to study the changes occurring in European eel Anguilla anguilla ovaries during hormonally‐induced vitellogenesis. Aside from classic techniques used to monitor ...the vitellogenic process, such as ovary histology, fat content analysis, sodium dodecyl sulphate–polyacrylamide gel electrophoresis (SDS–PAGE) and vitellogenin enzyme linked immunosorbent assay (ELISA), a new technique, Fourier‐transform infrared (FT‐IR) microspectroscopy, was used to analyse A. anguilla ovaries. The results from the different techniques provided different ways of approaching the same process. Although it is considered a time consuming approach, of all the employed techniques, histology provided the most direct evidences about vitellogenesis. SDS–PAGE and ELISA were also useful for studying vitellogenesis, whereas fat analysis cannot be used for this purpose. The FT‐IR analysis provided a representative IR spectrum for each ovarian stage (previtellogenic stage, early vitellogenic stage, mid‐vitellogenic stage and late vitellogenic stage), demonstrating that it is a valid method able to illustrate the distribution of the oocytes within the ovary slices. The chemical maps obtained confirmed changes in lipid concentrations and revealed their distribution within the oocytes at different maturational stages. When the results and the accuracy of the FT‐IR analysis were compared with those of the traditional techniques commonly used to establish the vitellogenic stage, it became evident that FT‐IR is a useful and reliable tool, with many advantages, including the fact that it requires little biological material, the costs involved are low, analysis times are short and last but not least, the fact that it offers the possibility of simultaneously analysing various biocomponents of the same oocyte.
Two bacterial strains, Lactobacillus fructivorans, isolated from sea bream (Sparus aurata) gut, and Lactobacillus plantarum, isolated from human faeces, were administered simultaneously, during sea ...bream development, using Brachionus plicatilis and/or Artemia salina as vectors. The probiotic treatment significantly affected gut colonization. To test the probiotic influence on stress responsiveness, sea bream fry, 47 days post-hatching (p.h.), were subjected to pH stress (from 8.6 to 6.3) and cumulative mortality, cortisol levels and HSP70 gene expression were analysed. Cortisol was selected, since under stress conditions its level increases. HSP70 was selected with consideration of its wide involvement in response to a great number of injuries, and because it protects cells probably by binding and refolding damaged proteins. The results obtained indicated that the administration of probiotic to sea bream fry induced higher HSP70 levels, indicating a greater potentiality to respond to the harmful conditions possibly present in fish farms. This hypothesis is supported by the fact that the levels of cortisol found were significantly lower (P < 0.05) in both groups under probiotic treatment. When pH was used as a stressor, it induced a higher cumulative mortality in the control; the mortality was found to be significantly lower in both treated groups. Interestingly, a significant increase (P < 0.05) in HSP70 gene expression was observed in all stressed groups. These results suggest an improvement in tolerance to acute stress of fry fed with probiotics.PUBLICATION ABSTRACT
Chemical analysis of the compounds present in sediment, although informative, often is not indicative of the downstream biological effects that these contaminants exert on resident aquatic organisms. ...More direct molecular methods are needed to determine if marine life is affected by exposure to sediments. In this study, we used an aquatic multi-species microarray and q-PCR to investigate the effects on gene expression in juvenile sea bream (
Sparus aurata) of two contaminated sediments defined as sediment 1 and 2, respectively, from marine areas in Northern Italy. Both sediments affected gene expression as evidenced by aquatic multi-species microarray analysis and q-PCR. Exposure of
S. aurata juveniles to sediment 1 and sediment 2 altered expression of genes that are biomarkers for endocrine disruption. There were differences between the effects of sediment 1 and sediment 2 on gene expression in
S. aurata juveniles indicating that the chemicals in the two sediments had different physiological targets. These results suggest that the classification of sediment solely on the basis of specific chemical profiles is inadequate, and not a true indicator of its potential to cause harmful effects. Our data also indicate that integration of physiochemical analysis and bioassays for monitoring the downstream harmful effects on aquatic organisms are required to gain a complete understanding of the effects of sediment on aquatic life.
At present, clownfishes are the best example of successfully captive bred ornamental specimens but little is known about the relationship between food enrichment and both larval growth and ...development. In fact, it is well known that a certain percentage of these fishes cultured in captive conditions show a miss-band pigmentation. In the present study, the effects of live prey enrichment on growth and pigmentation in false percula clownfish (Amphiprion ocellaris) larvae were tested.
Newly hatched A. ocellaris larvae were divided in three different groups and fed as follows: group A fed on enriched (Algamac 2000) B. plicatilis (10 ind./mL) from day 1 to day 5 post-hatch (ph); group B fed on enriched (Algamac 2000) B. plicatilis (10 ind./mL) followed by Artemia nauplii (5 ind./mL;) and group C fed on Algamac 2000 enriched B. plicatilis and Algamac 2000 enriched Artemia nauplii.
Samples of the larvae were collected on day 5 from group A and on day 11 ph in group B and C for morphometric and molecular analysis. On day 11 ph food enrichment resulted in a better growth of group C larvae respect to those of group B fed on not enriched Artemia nauplii (15.8±0.2 mg and 8.78±0.02 mm vs. 6.8±0.2 mg and 6.93±0.01 mm). Moreover, 36±2% of the juveniles obtained from group B showed a miss-band pigmentation as compared to 29±1% of the juveniles obtained from group C. At molecular level, the results obtained by Real-Time PCR are in agreement with the morphometric ones: a positive induction of the Insulin-like Growth Factor II (IGFII) and Peroxisome Proliferator Activated Receptor α and β (PPARα and PPARβ) gene expression and a reduction of Myostatin (MSTN) was observed in group C larvae fed on enriched live prey. IGFI gene expression was higher in group B.
The present study provides clear evidences of the positive role of Algamac 2000 on growth and pigmentation of captive cultured false percula clownfish.
In the present study we demonstrated the efficiency of the Mediterranean calanoid copepod
Centropages typicus as live prey in
Amphiprion clarkii larviculture. After hatching, larvae were divided into ...two experimental groups as follows: group A (control) fed rotifers followed by
Artemia nauplii and group B fed
C. typicus nauplii and copepodites. On day 11 post-hatch, larvae fed
C. typicus showed better survival and growth compared to those fed a standard rotifer/
Artemia diet (90
±
2 vs 43
±
2%; 6.6
±
0.2 vs 6.0
±
0.2 mm; 5.8
±
0.3 vs 4.5
±
0.3 mg, respectively). At a molecular level, a significant increase of insulin-like growth factors I and II (IGF I and IGF II) gene expression and a significant decrease of myostatin (MSTN) gene expression were evidenced in group B larvae fed copepods. Considering these results,
C. typicus may be recommended as a valuable life prey for
A. clarkii larviculture.
Copepods are the natural food items for marine fish larvae but are still difficult to be cultured on a continuous basis. Therefore, suitable storage techniques for copepod subitaneous eggs are of ...great interest. Cold‐stored copepod embryos still develop and retain a physiological activity during the cold storage period. As a consequence, their nutritional quality may change over the time of storage with these changes possibly affecting both eggs viability and larval fish survival and development. In this study, the clownfish, Amphiprion polymnus, was used as an experimental model to compare, for the first time, the effects of diets based on enriched rotifers and Artemia (control), Acartia tonsa copepods of a continuous culture and A. tonsa originated from 6 months cold‐stored eggs. The effects of the different diets were tested through morphometric, molecular and biochemical approach. This study demonstrated that after a 6 months cold storage period, the quality of copepods obtained from those eggs was suboptimal for A. polymnus larval rearing. In fact, larvae fed those copepods showed lower growth and survival performances respect to the other experimental groups.
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