Letteratura scientifica selezionata sul tema "Argyrosomus – Health"

The presence of small-sized (<300 µm) microplastics (MPs) in aquaculture facilities may threaten finfish hatchery, as their (in)voluntary ingestion by fish larvae may compromise nutritional requirements during early ontogeny, and consequently larval health and performance. Thus, we addressed the short-term effects (7 h) of polyethylene microplastics (0.1, 1.0, 10 mg/L, PE-MPs) in meagre larvae Argyrosomus regius (15 dph) in the presence/absence of food. Larval feeding behavior, oxidative stress status, neurotoxicity, and metabolic requirements were evaluated. Results showed that meagre larvae ingested PE-MPs regardless of their concentration, decreasing in the presence of food (Artemia metanauplii). The presence of PE-MPs compromised larval feeding activity at the highest concentration. Under starvation, exposed larvae activated the antioxidant defenses by increasing the total glutathione levels and inhibiting catalase activity, which seemed efficient to prevent oxidative damage. Such larvae also presented increased energy consumption potentially related to oxidative damage prevention and decreased neurotransmission. Biochemical responses of fed larvae showed a similar trend, except for LPO, which remained unaffected, except at 0.1 mg/PE-MPs/L. Our results suggest that small-sized MPs in finfish hatcheries may compromise larvae nutritional requirements, but at considerably higher levels than those reported in marine environments. Nevertheless, cumulative adverse effects due to lower MPs concentrations may occur.

Meagre Argyrosomus regius is a potential candidate for Mediterranean aquaculture diversification, although several health issues still represent important bottlenecks for its sustainable production, including systemic granulomatosis (SG). To evaluate the SG progression in meagre during a 10 mo period of cage ongrowing, a histopathological investigation was carried out on 108 meagre fed 3 different diets (commercial pellets, hydrated commercial pellets and defrosted sardines). Histological sections of the gills and visceral organs were examined and lesions referable to SG scored from 1-3 according to the severity of the granulomatosis. The kidney and liver were the most affected organs, showing the highest percentage of positivity for granulomas and severity of lesions along the whole observation period. Using a statistical mixed model (GLMM) followed by odds ratio analysis, an effect of diet and temperature was found: the severity of liver and digestive tract SG scores decreased in the Cage 3 group (defrosted sardines) and with increasing temperature (p < 0.05, negative estimates, odds ratio <1). These observations, in accordance with the literature, suggest that SG in meagre could be related to nutritional-metabolic factors with the possible influence of environmental factors such as temperature.

The objective of the present study was to evaluate the occurrence of pathogens and diseases in laboratory fish over a 10-year period at the Centre for Experimental Fish Pathology of Sicily, University of Messina. This report also emphasizes the adverse effects of subclinical infections on research endpoints, as well as the importance of animal health with respect to welfare. Infections in fish used for research can alter experimental outcomes, increase the variability of data, and impede experimental reproducibility. For this purpose, 411 diseased fish of different species (out of a total of 2820 fish) that belonged to four marine species ( Dicentrarchus labrax, Sparus aurata, Argyrosomus regius and Mugil cephalus) and to four fresh water species ( Danio rerio, Carassius auratus, Xiphophorus variatus and Poecilia reticulata) were examined in this study. Our results showed that mycobacteriosis and myxosporidiosis were the most important diseases found in our research fish, and the results represent a useful tool to obtain wider knowledge on the incidence of various diseases in different fish species. Further studies in this field are necessary to improve knowledge on the state of the health of fish used for research.

This research aimed to evaluate the effects of the inclusion of honey bee pollen (HBP) in meagre (Argyrosoumus regius) juveniles’ diets on growth performance, diet digestibility, intestinal morphology, and immunohistochemistry. Furthermore, stress-related molecular markers and biochemical blood profile of fish were evaluated, together with mineral trace and toxic element concentration in pollen and diets. Specimens of meagre (360) of 3.34 ± 0.14 g initial body weight, were randomly allocated to twelve 500 L circular tanks (30 fish per tank). Four diets were formulated: a control diet and three experimental diets with 1%, 2.5%, and 4% of HBP inclusion. All the growth parameters and crude protein and ether extract digestibility coefficients were negatively linearly affected by increased HBP inclusion (p < 0.0001). Histology of medium intestine showed slight signs of alterations in group HPB1 and HPB2.5 compared to control. Fish from HBP4 group showed severe alterations at the intestinal mucosa level. Immunohistochemical detection of TNF-α in the medium intestine showed the presence of TNF-α+ cells in the lamina propria, which resulted in accordance with the increased level of the TNF-α protein detected by immunoblotting in the liver. This stress situation was confirmed by the increased hepatic level of HSP70 (p < 0.05) in fish fed the HBP4 diet and by the linear decrease of total serum protein levels in HBP-containing diets (p < 0.0001). These negative effects can be related to the ultrastructure of the bee pollen grain walls, which make the bioactive substances unavailable and can irritate the intestine of a carnivorous fish such as meagre.

Passive Acoustic Monitoring (PAM) is a non-intrusive and cost-effective method capable of providing high-resolution, long-term information on the status and health of vocal populations and communities. To successfully monitor the same species over wide geographical and temporal scales, it is necessary to characterise the range of sound variability, as well as the consistency of sound features between populations. The meagre (Argyrosomus regius, Asso 1801) is an interesting case study because recent investigations suggest a wider vocal repertoire than previously described. In this study, meagre vocalizations were recorded and analysed from a variety of settings, ranging from rearing facilities to wild populations to provide a comprehensive characterisation of its vocal repertoire, while investigating the consistency of spawning sound features between populations. All sounds presented a similar acoustic structure in their basic unit (i.e. the pulse), while an important variability was found in the number of pulses; the meagre can emit sounds made of one single pulse or many pulses (up to more than 100). High level of overlap in the Principal Component Analysis made difficult to differentiate sound type clusters. Despite this, two sound types were identifiable: knocks (sounds from 1 to 3 pulses) and long grunts (sounds with more than 29 pulses). Discriminant Analysis carried out on PCA residuals showed that knock had the highest proportion of correct placement (92% of the observations correctly placed) followed by long grunts (80%). All other previously described sound types (intermediate grunt, short grunt and disturbance sounds) could not be separated and presented low levels of correct placement, suggesting that care should be taken when defining these as independent sound types. Finally, acoustic features consistency was found in meagre grunts emitted by different populations during spawning nights; statistical differences could be explained by recording settings and fish conditions. The results of this study provide important information for fostering PAM programs of wild meagre populations, while contributing to the discussion around the definition of fish sound types in vocal fish communities. Studies of this kind, which evaluate both variability and consistency of sound features, are of fundamental importance for maximising PAM efforts in the wild, at both the specific and the community level.

Lipids are essential components for fish because they contain fatty acids that are vital for regular growth and health. Fish oil is rich in eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA), which are essential fatty acids for carnivorous fish, and therefore this product has traditionally been used as the main source of lipids in fish feeds. However, with declining fisheries resources worldwide and the rapid expansion of the aquaculture industry pressuring this finite resource, such ingredients are becoming less available and more expensive. It is therefore necessary to explore the utilization of ingredients that are sustainable and competitive alternatives to fish oil in marine finfish feeds. This work investigated the effects of the substitution of fish oil with soybean oil on the growth performance, feed efficiency, fatty acid composition of the liver tissue and some health parameters in juvenile dusky kob, Argyrosomus japonicus; an increasingly popular sciaenid marine aquaculture species in South Africa. Six diets (18 % total lipid and 46 % protein) with increasing percentage substitution of fish oil with soybean oil (1, 14, 28, 42, 56 and 70 %) were fed to juvenile kob. After 84 days of feeding these diets to the fish, no significant differences in fish length and weight between treatments were observed. However, there was a significant trend of a decrease in specific growth rate, ranging from (± standard error) 0.87 ± 0.06 to 0.72 ± 0.04 % body weight day⁻¹, and condition factor, ranging from 1.59 ± 0.03 to 1.54 ± 0.02, with increasing vegetable oil replacement in the diets between days 56 and 84. There were no differences in red blood cell count, haematocrit and haemoglobin concentration after 206 days of feeding. However, visceral fat index (VFI) increased significantly from 1.08 ± 0.17 % for fish fed diets with 28 % soybean oil, to 2.24 ± 0.15 % for fish fed diets with 70 % soybean oil. Similarly, hepatosomatic index (HSI) increased significantly from 0.84 ± 0.08 % to 1.80 ± 0.12 % in the control diet and the 56 % soybean oil diet, respectively. After 206 days of feeding, fish fed diets with 42 to 70 % soybean oil showed greater number of lipid vacuoles in the liver, which were also larger in size, and hepatocytes nuclei were displaced to the cell periphery. The fatty acid composition of the liver tissue strongly corresponded to the fatty acid composition of the diets. Linoleic acid accumulated in the liver of the fish fed increasing soybean oil in the diets. In contrast, EPA and DHA decreased from 13.63 to 1.97 %, and 14.34 to 3.28 %, respectively, in the liver tissue of fish fed diets with increasing soybean oil content; consequently the n-3/n-6 ratio was also significantly reduced with inclusion of vegetable oil in the diets. The trend of decreasing growth rate with increasing oil replacement towards the end of the trial corresponds with increases in VFI, HSI, as well as the fatty acid accumulation and lipid vacuoles in the liver. This suggests that dusky kob is less able to metabolise soybean oil at increased substitution levels which would account for the poorer growth at higher levels. The dependence of fish on dietary marine oil decreased significantly with each inclusion of soybean oil in the diets. Nonetheless, the calculations based on the nutrient ratio presented positive outcomes for all treatments, that is, values of marine oil dependency ratio were below one for all treatments. It is concluded that soybean oil can replace fish oil in formulated diets for dusky kob up to a level of 28 % of total dietary lipids, as evidenced by the good growth and feed efficiency, and no apparent negative health effects observed up to this level.