Rodolfo Ballestrazzi - Academia.edu (original) (raw)

Papers by Rodolfo Ballestrazzi

Comparative Biochemistry and Physiology Part B: Comparative Biochemistry, 1991

Fish Physiology and Biochemistry, 1996

With the aim of comparing the effects of oral T 3 and NaC1 administration on trout hypoosmoregula... more With the aim of comparing the effects of oral T 3 and NaC1 administration on trout hypoosmoregulatory mechanisms, three groups of rainbow trout (Oncorhynchus mykiss Walbaum) held in freshwater (FW) were fed a basal diet (C), the same diet containing 8.83 ppm of 3,5,3'-triiodo-L-thyronine (T3) (T) or 10% (w/w) NaC1 (N) respectively for 30 d. They were then transferred to brackish water (BW) for 22 d and fed on diet C. Gill (Na++K+)-ATPase activity and its dependence on ATP, Na + and pH, number of gill chloride cells (CC), serum T 3 level as well as fish growth, condition factor (K) and mortality were evaluated. During the FW phase, as compared to C trout, T trout showed a two fold higher serum T 3 level, had unchanged gill (Na~+K+)-ATPase activity and increased CC number, whereas N trout showed higher gill (Na~+K+) -ATPase activity and CC number. At the end of the experiment the enzyme activity was in the order T > N > C groups and all groups showed similar CC number. Both treatments changed the enzyme activation kinetics by ATP and Na +. A transient increase in K value occurred in N group during the period of salt administration. In BW, T and N groups had higher and lower survival than C group respectively. Other parameters were unaffected by the treatments. This trial suggests that T 3 administration promotes the development of hypoosmoregulatory mechanisms of trout but it leaves the (Na++K+)-ATPase activity unaltered till the transfer to a hyperosmotic environment.

Fish Physiology and Biochemistry, 1996

With the aim of comparing the effects of oral T 3 and NaC1 administration on trout hypoosmoregula... more With the aim of comparing the effects of oral T 3 and NaC1 administration on trout hypoosmoregulatory mechanisms, three groups of rainbow trout (Oncorhynchus mykiss Walbaum) held in freshwater (FW) were fed a basal diet (C), the same diet containing 8.83 ppm of 3,5,3'-triiodo-L-thyronine (T3) (T) or 10% (w/w) NaC1 (N) respectively for 30 d. They were then transferred to brackish water (BW) for 22 d and fed on diet C. Gill (Na++K+)-ATPase activity and its dependence on ATP, Na + and pH, number of gill chloride cells (CC), serum T 3 level as well as fish growth, condition factor (K) and mortality were evaluated. During the FW phase, as compared to C trout, T trout showed a two fold higher serum T 3 level, had unchanged gill (Na~+K+)-ATPase activity and increased CC number, whereas N trout showed higher gill (Na~+K+) -ATPase activity and CC number. At the end of the experiment the enzyme activity was in the order T > N > C groups and all groups showed similar CC number. Both treatments changed the enzyme activation kinetics by ATP and Na +. A transient increase in K value occurred in N group during the period of salt administration. In BW, T and N groups had higher and lower survival than C group respectively. Other parameters were unaffected by the treatments. This trial suggests that T 3 administration promotes the development of hypoosmoregulatory mechanisms of trout but it leaves the (Na++K+)-ATPase activity unaltered till the transfer to a hyperosmotic environment.

Comparative Biochemistry and Physiology Part B: Comparative Biochemistry, 1991

Aquaculture International, 2003

Two hundred and twenty rainbow trouts (IBW: 700 g) were randomly allotted to four tanks, with a m... more Two hundred and twenty rainbow trouts (IBW: 700 g) were randomly allotted to four tanks, with a male/female ratio of 0.56. Fish were fed for 168 d with four experimental diets containing herring oil, cod liver oil and coconut oil with the following inclusion rates: diet A: 12-1-0% respectively; diet B: 6-1-6%; diet C: 0-1-12%; diet D: 0-0-13%. Irrespective of

Italian Journal of Animal Science, 2010

Fish in captivity can show some dysfunctions, at different levels, in the physiological processes... more Fish in captivity can show some dysfunctions, at different levels, in the physiological processes of reproduction, due to the lack of synthesis or release of gonadotropins (GtHs) by hypophysis. As a consequence, a worsening of quality and quantity of spawned gametes, or a lack of egg and sperm spawning, can be observed. The farmers can act on fish reproductive cycle manipulating the environmental parameters of rearing, the diet, the genetics or using GnRH treatments. Nowadays, they are used mainly GnRH, synthesized in laboratory as analogues. These releasing factors, naturally produced by hypothalamus, let to overcome the technological and biological limits of the "traditional" hormonal treatments with hCG, being more effective, cheaper and easily available on market. This article makes a historical survey of the conditioning treatments for fish reproduction and also considers the future perspectives of these treatments, examining the topics that research will have to focus, in order to make these treatments common worldwide, in any hatchery and for each farmed species of finfish.

Italian Journal of Animal Science, 2010

The voluntary feed intake (VFI) and growth rate of sea bass were studied for 147 days, based on d... more The voluntary feed intake (VFI) and growth rate of sea bass were studied for 147 days, based on different starting live weights, under natural photoperiods and varied water temperatures. Sea bass (n = 720) were divided into five weight classes (60-70, 90-110, 130-150, 160-180 and 230-250 g) and distributed among 20 tanks. Seven different water temperatures were compared: 13, 16, 19, 22, 25, 28 and 31 °C. A commercial extruded diet (N x 6.25, 43.7% DM; crude fat, 25.7% DM) was used. The trial was performed in a closed-circuit plant, with a daily water turnover rate of 10%. Each tank was fitted with an apparatus for collecting the uneaten food. Automatic feeders distributed equal amounts of food for ten meals per day. The daily food allowance was adjusted, based on fish biomass, to permit ad libitum feeding and to leave approximately 20% uneaten. Fish were exposed to natural photoperiod (March-July). Non-linear regression equations were used to calculate the best-fitting curves for the data.

Italian Journal of Animal Science, 2010

Three hundred rainbow trout (242.9 ± 6.9 g) were randomly assigned to 12 fibreglass tanks (25 fis... more Three hundred rainbow trout (242.9 ± 6.9 g) were randomly assigned to 12 fibreglass tanks (25 fish/tank). The fish were fed, for 231 days (feeding level: 0.74 % average bw), four experimental diets, containing increasing levels of coconut oil: diet A 0 %, diet B 6 %; diet C 12 % and diet D 13 %, as replacements of herring oil and cod liver oil. Weight gains of fish were > 3 g d -1 and FCR lower than 1.5, for all treatments. No significant difference was observed in the main carcass traits and whole body composition, but whole fish energy content significantly increased in fish fed diet D (10.68 KJ g -1 ). Different dietary fatty acid profiles had significant effects on the rainbow trout muscle contents of C10:0, C12:0, C14:0, total n-3, and the main ratios: SFA/USFA; DHA/EPA; DHA/AA, n-3/n-6, but not on total fatty acids content of the muscle.

Italian Journal of Animal Science, 2010

The aim of this work was to investigate the effects of vitamin E and phosphatidylcholine on rainb... more The aim of this work was to investigate the effects of vitamin E and phosphatidylcholine on rainbow trout (Oncorhynchus mykiss) milt. One hundred and twelve rainbow trout (RB) broodstock (2n, 1030± 20g body weight, male:female ratio = 50:50) were fed four isoproteic and isolipidic diets for 110 days. Diets were differing for the type of vitamin premix and phosphatidylcholine supplied: Control (vitamin premix without Vit. E, no phosphatidylcholine); Vit.E (a premix with Vit. E, no phosphatidylcholine); PhC, (vitamin premix without Vit. E, phosphatidylcholine 2.5%); Vit.E +PhC, (vitamin premix with Vit. E and phosphatidylcholine 2.5%). Sperm total volume, in sexually mature males (3+; 966±114g body weight), ranged between 18.57ml (Control) and 34.31ml (Vit. E). Sperm density varied between 1.76x10 9 Szoa/ml (Control) and 1.16x10 9 Szoa/ml (Vit. E+PhC), while relative density (related to male body weight) tended to increase with Vit. E (>50x10 9 Szoa/ml) and to reduce with Vit. E + PhC (<30x10 9 Szoa/ml). Percentage motility was >85% in all treatments, while motility duration was around 2.37min for Vit. E and Control reached only 0.97min. After overnight storage (+4°C, for 18 hours) motility decreased, 75-80% in gamete motility and 3.39-56.7% in time motility. PhC dietary supplements significantly increased arachidonic acid contents of sperm with respect to Control (>120 vs 73µg/ g), while Vit. E caused a huge increase in C20:3 n-3 (10.25 vs 2.27ppm). DHA/EPA ratio was significantly lower in Control (>2; p<0.05), while n-3/n-6 ratio was significantly the highest for Vit. E (9.46 vs <7.3).

Italian Journal of Animal Science, 2010

The biometry of wild berried females was collected during an entire reproductive season at the So... more The biometry of wild berried females was collected during an entire reproductive season at the South-Wexford Lobster Co-op hatchery in Nethertown, Ireland. Second degree regressions between total body weight (TW, g) and carapace length (CL, mm) (TW=CL 2 -36.675CL+1793.2, R 2 =0.9022) and number of "weaned" larvae and carapace length (Larvae number=1.217CL 2 -21.777CL-5281.1, R 2 =0.743) were observed. Afterwards, berried females were divided according to two variables: 1. holding system: recirculating system (Rs) vs barrel (Bar); 2. CL size: <101 mm (A), 101-120 mm (B), >120 mm (C). The total weight of larvae (212.5 vs 92.4 g) and their numbers (7788 vs 5679) were significantly higher for the largest females than for the smaller sizes (P<0.01). The maximum survival rate of larvae (77.86%) was noted for initial stocking density <1000 individuals/hopper, but the optimal stocking density for management purposes in the hatchery is higher (2001-3000 individuals/hopper).

Fish Physiology and Biochemistry, 2000

The high prevalence of opercular deformities present in fish from Mediterranean marine hatcheries... more The high prevalence of opercular deformities present in fish from Mediterranean marine hatcheries is an important problem, which is causing considerable economic losses. The aetiology of this syndrome is not yet well understood. In this study a histological and ultrastructural description of gilthead sea bream (Sparus aurata) larvae affected with anomalies of the opercular complex was carried out.

Fish Physiology and Biochemistry, 1996

With the aim of comparing the effects of oral T 3 and NaC1 administration on trout hypoosmoregula... more With the aim of comparing the effects of oral T 3 and NaC1 administration on trout hypoosmoregulatory mechanisms, three groups of rainbow trout (Oncorhynchus mykiss Walbaum) held in freshwater (FW) were fed a basal diet (C), the same diet containing 8.83 ppm of 3,5,3'-triiodo-L-thyronine (T3) (T) or 10% (w/w) NaC1 (N) respectively for 30 d. They were then transferred to brackish water (BW) for 22 d and fed on diet C. Gill (Na++K+)-ATPase activity and its dependence on ATP, Na + and pH, number of gill chloride cells (CC), serum T 3 level as well as fish growth, condition factor (K) and mortality were evaluated. During the FW phase, as compared to C trout, T trout showed a two fold higher serum T 3 level, had unchanged gill (Na~+K+)-ATPase activity and increased CC number, whereas N trout showed higher gill (Na~+K+) -ATPase activity and CC number. At the end of the experiment the enzyme activity was in the order T > N > C groups and all groups showed similar CC number. Both treatments changed the enzyme activation kinetics by ATP and Na +. A transient increase in K value occurred in N group during the period of salt administration. In BW, T and N groups had higher and lower survival than C group respectively. Other parameters were unaffected by the treatments. This trial suggests that T 3 administration promotes the development of hypoosmoregulatory mechanisms of trout but it leaves the (Na++K+)-ATPase activity unaltered till the transfer to a hyperosmotic environment.

European Journal of Pharmaceutics and Biopharmaceutics, 2011

The aim of this work was to enhance the bioavailability of erythromycin base when administered or... more The aim of this work was to enhance the bioavailability of erythromycin base when administered orally in rainbow trout (Oncorhynchus mykiss). Since erythromycin is normally given in the form of medicated feed, in this study three new types of feed formulation were developed. A self-emulsifying system and two types of double microemulsions (O/W/O) were prepared, characterized and adsorbed on a commercial extruded diet for fish. The emulsified systems were based on saturated polyglycolized glycerides and mono-and diglycerides of medium-chain fatty acids (as oily phase), Tween Ò 80 (as surfactant) and, in the case of double microemulsions, distilled water. The systems differed in percentage composition and for the amount and position of erythromycin in different phases. The three medicated feed were then administered orally by means of a gastric probe to rainbow trout and their relative bioavailability was estimated in comparison with that obtained after oral administration of feed with erythromycin powder. For each medicated feed, 80 fish were tested. Finally, plasma profiles of erythromycin after single administration of medicated feeds were used to predict profiles obtainable by administering once-daily medicated feeds for 7 consecutive days. The results proved that the feeds containing microemulsified erythromycin provided largely superior oral bioavailability and the advantage of obtaining the same efficacy against bacterial infections with a much lower dose of drug.

Aquaculture Research, 2013

Modelling growth as a function of feeding rate (FR) could be one of the most important tools for ... more Modelling growth as a function of feeding rate (FR) could be one of the most important tools for fish farms, because this knowledge allows growth to be maximized, or the feed conversion ratio (FCR) to be minimized, thereby improving profits. All growth models should include the three principal variables involved in growth: initial body weight, temperature and feeding rate. The thermal-unit growth coefficient (TGC) already includes water temperature variation and initial body weight. Studying variation in TGC for fish fed the same diet, but at several feeding rates provides interesting information for modelling. Six different trials were conducted where gilthead sea bream of several different initial weights (24, 38, 50, 110, 220 or 289 g) were fed increasing amounts, and growth and the conversion index response were measured. The TGC response was modelled as a function of FR, and both asymptotic and quadratic responses were examined. The asymptotic model, TGC 9 1000 = 2.037* (1Àe (À0.8*(FRÀ0.22) ), had an adjusted R 2 value of 96.18, whereas the quadratic model, TGC 9 1000 = À0.381 + 1,715 9 FRÀ0,382 9 FR 2 , had an adjusted R 2 value of 96.42. Simulations of the FCR and the economical profitability index (EPI) were conducted to provide tools for maximizing efficiency and profitability, and the results suggest that these tools will be useful for future investigations.

Aquaculture, 1999

0044-8486r99r$ -see front matter q 1999 Elsevier Science B.V. All rights reserved.

Italian Journal of Animal Science, 2010

The aim of this research was to study the main sperm characteristics of three different finfish s... more The aim of this research was to study the main sperm characteristics of three different finfish species. Twenty-one gilthead sea bream (Sparus aurata), 20 brown trout (Salmo trutta, morpha fario) and 15 rainbow trout (Oncorhynchus mykiss) male broodstocks, farmed under optimal conditions for each species and fed standard diets for broodstocks, were manually stripped. Brown trout yielded small amounts of sperm (4.5 vs 18.13 ml) that were very concentrated (≅ 8.5 x 10 9 vs 1.24 x 10 9 Szoa/ml) with respect to the other species. The duration of spermatozoan motility for gilthead sea bream sperm was significantly longer (almost 50 min), in comparison to the one-minute motility of Salmonids. Single fatty acids of brown trout sperm were higher than in the other two species for almost all detected fatty acids. In particular, eicosapentaenoic acid (EPA) was at least three times more concentrated in brown trout than in rainbow trout or gilthead sea bream sperm (1238.3 µg/g vs 305.6 and 333.3 µg/g, respectively; P < 0.01). Saturated, polyunsaturated and total unsaturated fatty acid classes were significantly higher in brown trout sperm than in the other two species -almost double with respect to gilthead sea bream sperm and more than double in comparison to RT sperm (P < 0.01).

Comparative Biochemistry and Physiology Part B: Comparative Biochemistry, 1991

Fish Physiology and Biochemistry, 1996

With the aim of comparing the effects of oral T 3 and NaC1 administration on trout hypoosmoregula... more With the aim of comparing the effects of oral T 3 and NaC1 administration on trout hypoosmoregulatory mechanisms, three groups of rainbow trout (Oncorhynchus mykiss Walbaum) held in freshwater (FW) were fed a basal diet (C), the same diet containing 8.83 ppm of 3,5,3'-triiodo-L-thyronine (T3) (T) or 10% (w/w) NaC1 (N) respectively for 30 d. They were then transferred to brackish water (BW) for 22 d and fed on diet C. Gill (Na++K+)-ATPase activity and its dependence on ATP, Na + and pH, number of gill chloride cells (CC), serum T 3 level as well as fish growth, condition factor (K) and mortality were evaluated. During the FW phase, as compared to C trout, T trout showed a two fold higher serum T 3 level, had unchanged gill (Na~+K+)-ATPase activity and increased CC number, whereas N trout showed higher gill (Na~+K+) -ATPase activity and CC number. At the end of the experiment the enzyme activity was in the order T > N > C groups and all groups showed similar CC number. Both treatments changed the enzyme activation kinetics by ATP and Na +. A transient increase in K value occurred in N group during the period of salt administration. In BW, T and N groups had higher and lower survival than C group respectively. Other parameters were unaffected by the treatments. This trial suggests that T 3 administration promotes the development of hypoosmoregulatory mechanisms of trout but it leaves the (Na++K+)-ATPase activity unaltered till the transfer to a hyperosmotic environment.

Fish Physiology and Biochemistry, 1996

With the aim of comparing the effects of oral T 3 and NaC1 administration on trout hypoosmoregula... more With the aim of comparing the effects of oral T 3 and NaC1 administration on trout hypoosmoregulatory mechanisms, three groups of rainbow trout (Oncorhynchus mykiss Walbaum) held in freshwater (FW) were fed a basal diet (C), the same diet containing 8.83 ppm of 3,5,3'-triiodo-L-thyronine (T3) (T) or 10% (w/w) NaC1 (N) respectively for 30 d. They were then transferred to brackish water (BW) for 22 d and fed on diet C. Gill (Na++K+)-ATPase activity and its dependence on ATP, Na + and pH, number of gill chloride cells (CC), serum T 3 level as well as fish growth, condition factor (K) and mortality were evaluated. During the FW phase, as compared to C trout, T trout showed a two fold higher serum T 3 level, had unchanged gill (Na~+K+)-ATPase activity and increased CC number, whereas N trout showed higher gill (Na~+K+) -ATPase activity and CC number. At the end of the experiment the enzyme activity was in the order T > N > C groups and all groups showed similar CC number. Both treatments changed the enzyme activation kinetics by ATP and Na +. A transient increase in K value occurred in N group during the period of salt administration. In BW, T and N groups had higher and lower survival than C group respectively. Other parameters were unaffected by the treatments. This trial suggests that T 3 administration promotes the development of hypoosmoregulatory mechanisms of trout but it leaves the (Na++K+)-ATPase activity unaltered till the transfer to a hyperosmotic environment.

Comparative Biochemistry and Physiology Part B: Comparative Biochemistry, 1991

Aquaculture International, 2003

Two hundred and twenty rainbow trouts (IBW: 700 g) were randomly allotted to four tanks, with a m... more Two hundred and twenty rainbow trouts (IBW: 700 g) were randomly allotted to four tanks, with a male/female ratio of 0.56. Fish were fed for 168 d with four experimental diets containing herring oil, cod liver oil and coconut oil with the following inclusion rates: diet A: 12-1-0% respectively; diet B: 6-1-6%; diet C: 0-1-12%; diet D: 0-0-13%. Irrespective of

Italian Journal of Animal Science, 2010

Fish in captivity can show some dysfunctions, at different levels, in the physiological processes... more Fish in captivity can show some dysfunctions, at different levels, in the physiological processes of reproduction, due to the lack of synthesis or release of gonadotropins (GtHs) by hypophysis. As a consequence, a worsening of quality and quantity of spawned gametes, or a lack of egg and sperm spawning, can be observed. The farmers can act on fish reproductive cycle manipulating the environmental parameters of rearing, the diet, the genetics or using GnRH treatments. Nowadays, they are used mainly GnRH, synthesized in laboratory as analogues. These releasing factors, naturally produced by hypothalamus, let to overcome the technological and biological limits of the "traditional" hormonal treatments with hCG, being more effective, cheaper and easily available on market. This article makes a historical survey of the conditioning treatments for fish reproduction and also considers the future perspectives of these treatments, examining the topics that research will have to focus, in order to make these treatments common worldwide, in any hatchery and for each farmed species of finfish.

Italian Journal of Animal Science, 2010

The voluntary feed intake (VFI) and growth rate of sea bass were studied for 147 days, based on d... more The voluntary feed intake (VFI) and growth rate of sea bass were studied for 147 days, based on different starting live weights, under natural photoperiods and varied water temperatures. Sea bass (n = 720) were divided into five weight classes (60-70, 90-110, 130-150, 160-180 and 230-250 g) and distributed among 20 tanks. Seven different water temperatures were compared: 13, 16, 19, 22, 25, 28 and 31 °C. A commercial extruded diet (N x 6.25, 43.7% DM; crude fat, 25.7% DM) was used. The trial was performed in a closed-circuit plant, with a daily water turnover rate of 10%. Each tank was fitted with an apparatus for collecting the uneaten food. Automatic feeders distributed equal amounts of food for ten meals per day. The daily food allowance was adjusted, based on fish biomass, to permit ad libitum feeding and to leave approximately 20% uneaten. Fish were exposed to natural photoperiod (March-July). Non-linear regression equations were used to calculate the best-fitting curves for the data.

Italian Journal of Animal Science, 2010

Three hundred rainbow trout (242.9 ± 6.9 g) were randomly assigned to 12 fibreglass tanks (25 fis... more Three hundred rainbow trout (242.9 ± 6.9 g) were randomly assigned to 12 fibreglass tanks (25 fish/tank). The fish were fed, for 231 days (feeding level: 0.74 % average bw), four experimental diets, containing increasing levels of coconut oil: diet A 0 %, diet B 6 %; diet C 12 % and diet D 13 %, as replacements of herring oil and cod liver oil. Weight gains of fish were > 3 g d -1 and FCR lower than 1.5, for all treatments. No significant difference was observed in the main carcass traits and whole body composition, but whole fish energy content significantly increased in fish fed diet D (10.68 KJ g -1 ). Different dietary fatty acid profiles had significant effects on the rainbow trout muscle contents of C10:0, C12:0, C14:0, total n-3, and the main ratios: SFA/USFA; DHA/EPA; DHA/AA, n-3/n-6, but not on total fatty acids content of the muscle.

Italian Journal of Animal Science, 2010

The aim of this work was to investigate the effects of vitamin E and phosphatidylcholine on rainb... more The aim of this work was to investigate the effects of vitamin E and phosphatidylcholine on rainbow trout (Oncorhynchus mykiss) milt. One hundred and twelve rainbow trout (RB) broodstock (2n, 1030± 20g body weight, male:female ratio = 50:50) were fed four isoproteic and isolipidic diets for 110 days. Diets were differing for the type of vitamin premix and phosphatidylcholine supplied: Control (vitamin premix without Vit. E, no phosphatidylcholine); Vit.E (a premix with Vit. E, no phosphatidylcholine); PhC, (vitamin premix without Vit. E, phosphatidylcholine 2.5%); Vit.E +PhC, (vitamin premix with Vit. E and phosphatidylcholine 2.5%). Sperm total volume, in sexually mature males (3+; 966±114g body weight), ranged between 18.57ml (Control) and 34.31ml (Vit. E). Sperm density varied between 1.76x10 9 Szoa/ml (Control) and 1.16x10 9 Szoa/ml (Vit. E+PhC), while relative density (related to male body weight) tended to increase with Vit. E (>50x10 9 Szoa/ml) and to reduce with Vit. E + PhC (<30x10 9 Szoa/ml). Percentage motility was >85% in all treatments, while motility duration was around 2.37min for Vit. E and Control reached only 0.97min. After overnight storage (+4°C, for 18 hours) motility decreased, 75-80% in gamete motility and 3.39-56.7% in time motility. PhC dietary supplements significantly increased arachidonic acid contents of sperm with respect to Control (>120 vs 73µg/ g), while Vit. E caused a huge increase in C20:3 n-3 (10.25 vs 2.27ppm). DHA/EPA ratio was significantly lower in Control (>2; p<0.05), while n-3/n-6 ratio was significantly the highest for Vit. E (9.46 vs <7.3).

Italian Journal of Animal Science, 2010

The biometry of wild berried females was collected during an entire reproductive season at the So... more The biometry of wild berried females was collected during an entire reproductive season at the South-Wexford Lobster Co-op hatchery in Nethertown, Ireland. Second degree regressions between total body weight (TW, g) and carapace length (CL, mm) (TW=CL 2 -36.675CL+1793.2, R 2 =0.9022) and number of "weaned" larvae and carapace length (Larvae number=1.217CL 2 -21.777CL-5281.1, R 2 =0.743) were observed. Afterwards, berried females were divided according to two variables: 1. holding system: recirculating system (Rs) vs barrel (Bar); 2. CL size: <101 mm (A), 101-120 mm (B), >120 mm (C). The total weight of larvae (212.5 vs 92.4 g) and their numbers (7788 vs 5679) were significantly higher for the largest females than for the smaller sizes (P<0.01). The maximum survival rate of larvae (77.86%) was noted for initial stocking density <1000 individuals/hopper, but the optimal stocking density for management purposes in the hatchery is higher (2001-3000 individuals/hopper).

Fish Physiology and Biochemistry, 2000

The high prevalence of opercular deformities present in fish from Mediterranean marine hatcheries... more The high prevalence of opercular deformities present in fish from Mediterranean marine hatcheries is an important problem, which is causing considerable economic losses. The aetiology of this syndrome is not yet well understood. In this study a histological and ultrastructural description of gilthead sea bream (Sparus aurata) larvae affected with anomalies of the opercular complex was carried out.

Fish Physiology and Biochemistry, 1996

With the aim of comparing the effects of oral T 3 and NaC1 administration on trout hypoosmoregula... more With the aim of comparing the effects of oral T 3 and NaC1 administration on trout hypoosmoregulatory mechanisms, three groups of rainbow trout (Oncorhynchus mykiss Walbaum) held in freshwater (FW) were fed a basal diet (C), the same diet containing 8.83 ppm of 3,5,3'-triiodo-L-thyronine (T3) (T) or 10% (w/w) NaC1 (N) respectively for 30 d. They were then transferred to brackish water (BW) for 22 d and fed on diet C. Gill (Na++K+)-ATPase activity and its dependence on ATP, Na + and pH, number of gill chloride cells (CC), serum T 3 level as well as fish growth, condition factor (K) and mortality were evaluated. During the FW phase, as compared to C trout, T trout showed a two fold higher serum T 3 level, had unchanged gill (Na~+K+)-ATPase activity and increased CC number, whereas N trout showed higher gill (Na~+K+) -ATPase activity and CC number. At the end of the experiment the enzyme activity was in the order T > N > C groups and all groups showed similar CC number. Both treatments changed the enzyme activation kinetics by ATP and Na +. A transient increase in K value occurred in N group during the period of salt administration. In BW, T and N groups had higher and lower survival than C group respectively. Other parameters were unaffected by the treatments. This trial suggests that T 3 administration promotes the development of hypoosmoregulatory mechanisms of trout but it leaves the (Na++K+)-ATPase activity unaltered till the transfer to a hyperosmotic environment.

European Journal of Pharmaceutics and Biopharmaceutics, 2011

The aim of this work was to enhance the bioavailability of erythromycin base when administered or... more The aim of this work was to enhance the bioavailability of erythromycin base when administered orally in rainbow trout (Oncorhynchus mykiss). Since erythromycin is normally given in the form of medicated feed, in this study three new types of feed formulation were developed. A self-emulsifying system and two types of double microemulsions (O/W/O) were prepared, characterized and adsorbed on a commercial extruded diet for fish. The emulsified systems were based on saturated polyglycolized glycerides and mono-and diglycerides of medium-chain fatty acids (as oily phase), Tween Ò 80 (as surfactant) and, in the case of double microemulsions, distilled water. The systems differed in percentage composition and for the amount and position of erythromycin in different phases. The three medicated feed were then administered orally by means of a gastric probe to rainbow trout and their relative bioavailability was estimated in comparison with that obtained after oral administration of feed with erythromycin powder. For each medicated feed, 80 fish were tested. Finally, plasma profiles of erythromycin after single administration of medicated feeds were used to predict profiles obtainable by administering once-daily medicated feeds for 7 consecutive days. The results proved that the feeds containing microemulsified erythromycin provided largely superior oral bioavailability and the advantage of obtaining the same efficacy against bacterial infections with a much lower dose of drug.

Aquaculture Research, 2013

Modelling growth as a function of feeding rate (FR) could be one of the most important tools for ... more Modelling growth as a function of feeding rate (FR) could be one of the most important tools for fish farms, because this knowledge allows growth to be maximized, or the feed conversion ratio (FCR) to be minimized, thereby improving profits. All growth models should include the three principal variables involved in growth: initial body weight, temperature and feeding rate. The thermal-unit growth coefficient (TGC) already includes water temperature variation and initial body weight. Studying variation in TGC for fish fed the same diet, but at several feeding rates provides interesting information for modelling. Six different trials were conducted where gilthead sea bream of several different initial weights (24, 38, 50, 110, 220 or 289 g) were fed increasing amounts, and growth and the conversion index response were measured. The TGC response was modelled as a function of FR, and both asymptotic and quadratic responses were examined. The asymptotic model, TGC 9 1000 = 2.037* (1Àe (À0.8*(FRÀ0.22) ), had an adjusted R 2 value of 96.18, whereas the quadratic model, TGC 9 1000 = À0.381 + 1,715 9 FRÀ0,382 9 FR 2 , had an adjusted R 2 value of 96.42. Simulations of the FCR and the economical profitability index (EPI) were conducted to provide tools for maximizing efficiency and profitability, and the results suggest that these tools will be useful for future investigations.

Aquaculture, 1999

0044-8486r99r$ -see front matter q 1999 Elsevier Science B.V. All rights reserved.

Italian Journal of Animal Science, 2010

The aim of this research was to study the main sperm characteristics of three different finfish s... more The aim of this research was to study the main sperm characteristics of three different finfish species. Twenty-one gilthead sea bream (Sparus aurata), 20 brown trout (Salmo trutta, morpha fario) and 15 rainbow trout (Oncorhynchus mykiss) male broodstocks, farmed under optimal conditions for each species and fed standard diets for broodstocks, were manually stripped. Brown trout yielded small amounts of sperm (4.5 vs 18.13 ml) that were very concentrated (≅ 8.5 x 10 9 vs 1.24 x 10 9 Szoa/ml) with respect to the other species. The duration of spermatozoan motility for gilthead sea bream sperm was significantly longer (almost 50 min), in comparison to the one-minute motility of Salmonids. Single fatty acids of brown trout sperm were higher than in the other two species for almost all detected fatty acids. In particular, eicosapentaenoic acid (EPA) was at least three times more concentrated in brown trout than in rainbow trout or gilthead sea bream sperm (1238.3 µg/g vs 305.6 and 333.3 µg/g, respectively; P < 0.01). Saturated, polyunsaturated and total unsaturated fatty acid classes were significantly higher in brown trout sperm than in the other two species -almost double with respect to gilthead sea bream sperm and more than double in comparison to RT sperm (P < 0.01).