Giulia Maricchiolo

Response to short term starvation of growth, haematological, biochemical and non-specific immune parameters in European sea bass (Dicentrarchus labrax) and blackspot sea bream (Pagellus bogaraveo)

Growth, haematological (haematocrit), biochemical (serum cortisol and glucose), and non-specific immune (lysozyme, serum haemolytic and haemagglutinating activities, extracellular respiratory burst activity) parameters, were monitored in European sea bass Dicentrarchus labrax and blackspot sea bream Pagellus bogaraveo subjected to a 31 days starvation compared to fed fish, to assess the responses to feed deprivation of these health status indicators. While haematocrit, serum cortisol, glucose and haemolytic activity of both species did not undergo significant variation following starvation, probably due to the short period applied, some non-specific immune parameters were affected significantly. In the starved sea bass, mucus lysozyme content doubled (1.8 U/mL) compared to the initial value. Haemagglutinating activity was significantly lower in starved sea bass than in fed fish after 31 days. In blackspot sea bream, a slight, not significant, reduction in haemagglutinating activity occurred 11 days after starvation. Respiratory burst activity decreased significantly in the starved fish. In spite of the limited number of examined parameters, the opportunity to use a panel of several indicators to obtain a more complete picture of health status in fish was underlined.

Short fasting and refeeding in red porgy (Pagrus pagrus, Linnaeus 1758): Response of some haematological, biochemical and non specific immune parameters

A short fasting-refeeding experience was applied to specimens of red porgy, Pagrus pagrus (Teleostei, Sparidae) to assess its effects on some physiological parameters. Haematological (haematocrit), biochemical (serum cortisol and glucose) and immunological (lysozyme, haemolytic and haemagglutinating activities) parameters were measured. For this study, two fish groups were considered: one was fasted for 14 days and then refed to satiation during further 7 and 15 days (indicated as fasted/refed group), the other was fed throughout the study and was taken as a control group. Significantly lower values were recorded for the condition index, the hepato-somatic index and viscero-somatic index in the fasted/refed group compared to the fed one. Fasting did not affect significantly the examined parameters, except for cortisol; refeeding for 7 days induced a significant increase in the haemoagglutinating titre and the spontaneous haemolytic activity, but when refeeding was extended to 14 days haemagglutinating and haemolytic values remained lower than those measured in fed fish.

Some Contributions to Knowledge of Stress Response in Innovative Species with Particular Focus on the Use of the Anaesthetics

This study investigated some aspects of stress research, including, also, the effects of chemical anaesthesia, in two important species for diversification in aquaculture, blackspot seabream, Pagellus bogaraveo and greater amberjack, Seriola dumerilii. The first part of the research (trial 1 and 2) was designed to determine the efficacy of clove oil as an anaesthetic alternative to MS-222. In trial 1, the minimum concentration of anaesthetic producing the total loss of muscular tone within 3 min, and recovery within 10 min, was determined. The obtained results showed that MS-222 and clove oil were effective as anaesthetics for juveniles of blackspot sea-bream and greater amberjack at concentrations of 40 and 100 mg L -1 , respectively. The aim of trial 2 was to assess the side-effects of both anaesthetics on greater amberjack juveniles by monitoring serum cortisol and glucose levels, and haematocrit values. No significant differences between anaesthetics were found for most of the measured physiological variables. The second part of research (trial 3) was designed to establish the ability of anaesthesia to mitigate stress responses blocking activation of the HPI axis associated to handling stress. In this trial, the stress responses to handling of adult blackspot sea-bream anaesthetised with either anaesthetics were compared to those of unanaesthetised fish used as controls. Serum cortisol and glucose concentrations were used as stress indicators. Both anaesthetics were unable to block activation of the HPI axis that occurs as a consequence of handling stress in blackspot sea-bream, although anaesthesia with both anaesthetics proved to be effective in reducing the duration of stress response.

Rice protein-concentrate meal as a potential dietary ingredient in practical diets for blackspot seabream Pagellus bogaraveo: a histological and enzymatic investigation

Field and laboratory studies were conducted to evaluate the intestinal responses to partial replacement of fish meal with rice protein concentrate (RPC) in practical diets for blackspot seabream Pagellus bogaraveo. Two experimental diets were formulated to be isoproteic and isoenergetic with an increasing level of RPC (20 and 35%, respectively) and were tested against a fish meal-based control diet (RPC0). The diets showed similar features for growth performances and both intestinal histology and digestive enzymes. This study confirmed that RPC does not induce intestinal mucosa alterations in this fish. The dietary RPC supplement caused a significant increase in trypsin activity, whereas lipase activity was reduced.

Haematological and Immunological Responses in Juvenile Sea Bass (Dicentrarchus labrax L.) After Short-Term Acute Stress

The physiological effects of acute stress (induced by an intraperitoneal injection) on the haematocrit, haemo- globin, serum cortisol and glucose, haemagglutinins and lysozyme were investigated in juvenile sea bass Dicentrarchus labrax. A total of 40 fish were subjected to an intraperitoneal injection. Eight fish were sampled at 0, 2, 4, 24 and 48 h af- ter acute stress and compared to unstressed fish (controls) sacrificed at the same times. Intraperitoneal injection resulted in significant changes in cortisol and glucose 4 and 2 hours after exposure to stress, respectively, but not in haematocrit and haemoglobin levels. No significant differences between stressed and control fish were recorded for lysozyme content and haemagglutinating activity throughout the experiment. In juvenile sea bass acute stress caused by intraperitoneal injection was mostly associated with the increase in common stress indicators (cortisol and glucose), while no clear response in terms of non-specific immune parameters was evidenced.

Alternative Dietary Sources in Feeding of Blackspot Sea Bream Pagellus bogaraveo (Brunnich, 1768)

The present review reports the results of two studies carried out at the Institute for the Coastal Marine Environment of Messina (Italy) on the suitability of plant-derived raw materials as dietary components for an innovative fish species for aquaculture, black spot sea bream Pagellus bogaraveo. The research focused on the effects of the use of plant (protein/lipid) dietary sources on growth performance, body composition and gastro-intestinal enzyme patterns in nutrient digestion of wild juveniles of P. bogaraveo. In particular, the effect of a total replacement of Fish oil by Echium and linseed oils and a partial substitution of fish meal with a graded level of Rice Protein Concentrate, will be discussed.

The Reproductive Biology of Pagellus bogaraveo, a New Candidate Species for Aquaculture

A brief review of investigations carried out at IAMC-CNR Messina on the reproductive biology of farmed blackspot sea bream Pagellus bogaraveo, a new candidate species for aquaculture, is presented. Different aspects of sexuality, including hermaphroditism, gametogenesis, spermatozoal ultrastructure, maturity staging, seasonal development of gonads, and spawning in captivity, were studied. Protandrous hermaphroditism appeared to be the prevalent sexual pattern, although a high incidence of gonochorism occurred. Males were most abundant in smaller size classes and reached sexual maturity at 28.0 cm, while females predominated in the larger size classes and reached maturity at 29.5 cm. The reproductive season lasted from February until April, as in the natural environment. Spontaneous spawning in tank occurred occasionally, whereas approximately 50% of females produced eggs upon stripping. The remaining 50% failed to ovulate, or even to achieve oocyte maturation, indicating an impaired reproductive functionality. A high incidence of oocyte atresia was also recorded. Males produced a small quantity of highly viscous milt, containing only 3% motile spermatozoa. The spermatozoon of P.bogaraveo has an ovoid head, a midpiece containing only one mitochondrion, and a 50.64 ± 4.82 μm long flagellum, inserted perpendicularly and eccentrically into the nucleus.

Supplementation of Vitamins, Minerals, Enzymes and Antioxidants in Fish Feeds

The fast increase in marine aquaculture productions has generated some problems related to optimization of fish feed. Moreover, the search for alternative raw materials to supplement or replace fishmeal and fish oil has made the introduction of additives into the diet necessary. Diet additives have recently attracted attention and investments of the aquaculture industry and, consequently, researches aimed at evaluating the costs/benefits ratio and the effects on organisms and environments are increasing. In general, additives are nutritive or nonnutritive ingredients that are added to the diet alone or in combination with each other and that are present in small quantities. Their functions are different: preserve the physical and chemical features of the diet, enhance animal health and welfare, improve the quality of final product and maintain the quality of aquatic environment. This chapter provides an overview of the use of vitamins, minerals and antioxidants in fish feeds. In addition to these natural substances, also enzymes are proposed as new alternative aquafeed additives. The effects on fish growth, welfare, reproduction and health status of the above-reported additives are discussed.

Sustainable Alternatives for Dietary Fish Oil in Aquafeeds: Actual Situation and Future Perspectives

Fishmeal and fish oil have been for a long time the dominant raw materials for aquaculture feeds but these are limited and finite resources. Plant oils extracted from oilseeds are the main candidates as sustainable substitutes for fish oil in fish feeds and many studies have demonstrated the feasibility of their use. Plant oils are rich in linoleic and α-linolenic acids but lack in eicosapentaenoic and docosahexaenoic acids that belong to omega-3 long-chain polyunsaturated fatty acids and whose food consumption has been shown to have beneficial effects on human health. In the light of these considerations, it is clear that the most important problem of the replacement of dietary fish oil with plant oils is a reduction of the nutritional value of the flesh of farmed fish. This review attempts to provide an overview of the effects of the major plant lipid sources alternative to fish oil tested in studies carried out on farmed fish species.

Fishery Discard as a Source of Food for Reared or Wild Fish? The Bottom Trawling in the Mediterranean Sea as a Case Study

Fisheries products found in the landing places or markets usually represent a fraction of what has been originally taken out from the sea by fishermen. A more or less variable amount of the gross (or overall or initial) catch, in fact, is returned either dead or alive to the sea for multiple reasons. This phenomenon, generally known as ‘the discard problem’, has raised more and more global concern especially in the last decades since introducing more selectivity gears and acquiring more reliable catch data (also about the survival rate of the discarded specimens) are considered basic requirements in the current management plans for recovering and rebuilding fish stocks. To this concern, the current Common Fisheries Policy aims to reduce the discard rate in the European waters through the introduction of a landing obligation (better ‘discard ban’) according to which all the specimens of the ‘target’ stock caught must be landed. This chapter focuses on the characterization of the catch returned to the sea ‘potential’ available to be landed after the introduction of landing obligation, and the possible use as a potential food source in aquaculture (the direct use for human consumption is in fact prohibited).