Benedetto Sicuro

The use of ozone in trout hatchery to reduce saprolegniasis incidence.

At present, the prophylactic measures in trout hatchery are based on the use of formaldehyde. The purpose of this work is to set up an alternative system of prevention of saprolegniasis, using ozone. The experiment was carried out in two successive cycles. The first experiment lasted 46 days and five different treatments were applied on every second day on the same number of lots of 250 eggs each, of which three were treated with ozone (O3) in concentrations of 0.01, 0.03 and 0.2 ppm (10 min), one reference treatment with formaldehyde (1–2 ml/l, 15 min) and one as control, without any disinfectants. The second experiment, which lasted 60 days, consisted also of five levels of treatment on the same number of lots of 100 eggs each, to which 0.01 ppm O3 (10 min) was applied on every second day, while 0.01, 0.1 and 0.3 ppm O3 (10 min) were applied daily. The formaldehyde treatment was performed in the same way as the experiment 1 (exp. 1). From the results, it has emerged that the treatment with ozone is effective and the hatching eggs range from 42.6% to 49.1% dose of ozone from 0.01 to 0.2 ppm. As observed in experiment 2 (exp. 2), the dose of 0.3 ppm applied every second day seems to be over the threshold of toxicity.

The State of Seriola spp. Other Than Yellowtail (S. quinqueradiata) Farming in the World

ABSTRACT The aim of this review is to provide an update of Seriola spp. farming in the world, excluding yellowtail (S. quinqueradiata), and to identify strengths and weaknesses of these species as candidates for aquaculture diversification in different areas of the world. Farmed Seriola species other than yellowtail are yellowtail kingfish (S. lalandi) in Japan and Australia, longfin yellowtail (S. rivoliana) in the United States, greater amberjack (S. dumerili) in Japan, the Mediterranean and more recently Vietnam, and Pacific yellowtail (S. mazatlana) in North and Central America. Candidate countries for Seriola spp. farming development are China (although there are no published production statistics to date), New Zealand and the Canary Islands. The main bottlenecks for further expansion of Seriola spp. farming appear to be disease impact, lack of genetic improvement programs, and incomplete knowledge of nutrient requirements. Extensive experience from Japan, where the success of Seriola spp. farming has been based on an integrated system between producer associations, research institutes and central government, it is clear that the aforementioned technical bottlenecks need to be addressed within a framework of medium-term public policies supporting aquaculture development.

A description of ammonium content of output waters from trout farms in relation to stocking density and flow rates

Abstract Daily levels of ammonium content in the outflow water of an intensive trout farm and of a mountain pond stocked with rainbow trout were monitored. Output water was sampled for 30 days and analysed every 30 min by an automatic ion selective electrode system (Applikon ADI 2013); input water was also monitored. The ammonium output level was influenced more by atmospheric events than nitrogen excretion by fish. Observed data confirmed an overall ammonium excretion model previously estimated in both laboratory and field conditions. The high water flow, that characterises the intensive trout farm where the observations were made induced a high dilution of metabolites. Consequently, if the peaks of ammonium output did not reach values of 0.35–0.40 mg l −1 the environmental impact was limited and not easily detected. Our results allow us to affirm that the optimal level of water flow rate for effective zeolite-operated filtration is around 10.3 l t −1 s −1 .

Effect of formulated diets on the proximate composition and fatty acid profiles of sea urchin Paracentrotus lividus gonad

Three formulated diets were tested to evaluate their effects on gonad quality in Paracentrotus lividus. Experiments were conducted in parallel by the Consiglio Nazionale delle Ricerche (CNR) of Taranto (trial 1) and the University of Genoa (trial 2), in land-based systems. In both trials, somatic and gonadsomatic index (GSI) were measured and the nutritional profile of the sea urchins has determined significant variations in the biochemical composition. Sea urchins fed the experimental diets contained higher levels of nutrients (protein and lipid and carbohydrate) compared to wild sea urchins. However, total polyunsaturated fatty acids (PUFAs), especially EPA and DHA, and the n-3/n-6 ratio were lower in urchins fed with formulated diets. In both trials, sea urchins fed with diet 2 (SABS) showed a similar profile with PUFAs higher than SAFAs and MUFAs, the highest UNS/SAT ratio, although the highest n3/n6 ratio was observed in the group fed diet 3 (CNR). Atherogenicity, thrombogenicity, and hypocholesterolemic/hypercholesterolemic indices showed the best values in sea urchins fed diet 2 in both trials.

Effect of Feeding Level on Nutritional Quality of Rainbow Trout (Oncorhynchus mykiss) Flesh

ABSTRACT The effect of different feeding levels (1.2%, 1.4%, 1.8% and to satiety) on the growth skill, morphological indexes and chemical composition of the dorsal muscle of rainbow trout (Oncorhynchus my-kiss) have been investigated. Significant differences were observed for the morphological indexes which increased with feeding level. For instance, the increase of feeding level induces a decrease in moisture content in the muscle composition, which corresponds to an increase of fat. Feeding level modified phospholipids, triglycerids and fatty acids content. These results can be of potential interest for the consumer from a diet point of view, and for the fish processing industry, since the processing and safe preservation of finished products are strictly linked to the chemical characteristics of fresh product.

Freshwater bivalves rearing: a brief overview

Freshwater bivalves farming is principally focused on freshwater pearl production in Asia and conservation aquaculture in USA while in Europe is almost completely unknown. High larval mortality is considered the bottleneck in freshwater bivalve larval rearing and methods currently used in marine bivalve larval rearing can be transferred in freshwater mussels. It is likely that probiotics and aquatic microbiology will play a key role also in freshwater bivalves larval rearing. Alternative applications of freshwater mussel rearing should be studied in deep in the future as integrated productions, bioindication projects and utilization of freshwater mussel meal as potential source for fish feeds. The aim of this review is to give a description of potential applications for freshwater bivalve rearing and possible future perspectives.

Animal welfare in brown trout farming: hematological results

Riassunto Benessere animale nell’allevamento della trota fario: risultati ematologici. Questa sperimentazione riguarda i parametri ematologici come indicatori di benessere nell’allevamento della trota fario. Sono stati effettuati due cicli sperimentali, il primo da marzo a luglio 2004, il secondo da settembre a novembre 2004. Durante il primo periodo i livelli del trattamento sperimentale sono stati 3: densità di allevamento di trota fario 5, 10 e 20 kg/m3. Sono stati rilevati cortisolo e glicemia. Durante il secondo periodo sperimentale son cambiate le densità di allevamento, corrispondenti a 10, 30 e 60 kg/m3 (LD, MD e HD), sono stati rilevati emato crito, glicemia, colesterolo e cortisolo. I risultati ottenuti indicano che ci sono differenze significative nel caso del l’ematocrito (%). Nel caso del cortisolo (ng/ml) si sono registrate differenze significative nei tre gruppi sperimentali tra i valori medi (LD = 48,4±25,1; MD = 24,2±11,9; HD = 79,5±30,7), tuttavia i livelli più bassi sono stati rilevati nel gruppo sperimentale a densità intermedia.

Reasons and Possibilities of Fish Meal Replacement in the Siberian Sturgeon

Although several fish feed companies currently produce commercial sturgeon feeds, in Siberian sturgeon farming, most farmers usually use nonspecific fish diets, particularly high-energy salmonid diets. Considering the general situation and trend of finfish nutrition, it is clear that forage fish meal should be reduced at minimum quantity in the future of fish artificial nutrition. For this reason, new ingredients already tested with other species have been progressively introduced in Siberian sturgeon nutrition. Fish meal replacement has substantially followed the path of salmonid artificial feeding. Most commonly used vegetal protein alternative to fish meal has been initially soybean meal and successively soybean meal included in blends of vegetal proteins. Between animal protein sources, blends of rendered animal proteins have been recently used with success. The replacement of fish meal with rendered terrestrial animal products added with lysine and methionine appears the most interesting possibility in the future as no adverse effect of fish growth and substantial modifications on fish body composition have been observed, while replacement with vegetal protein appears less attractive solution as soybean meal can interfere in fish reproduction for the presence of phytoestrogens.

Use of rice protein concentrate in rainbow trout feeding: preliminary results

Riassunto Impiego di un concentrato proteico di riso nell’alimentazione della trota iridea: risultati preliminari. E’ stato valutato l’effetto di un concentrato proteico di riso (RPC) in parziale sostituzione alla farina di pesce sulle prestazioni zootecniche di trota iridea. Dopo 94 giorni di alimentazione sono stati rilevati i parametri produttivi e gli indici somatici. Alla fine della prova sono emerse differenze significative per quanto attiene l’incremento in peso, l’indice di conversione alimentare, il tasso di accrescimento specifico e l’efficienza proteica. Relativamente agli indici somatici, si sono evidenziate differenze statisticamente significative a carico dell’indice viscerosomatico e del coefficiente di adiposità.