Nicola De Riu

Università degli Studi di Sassari, Sassari, Sardinia, Italy

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Publications (12)12.91 Total impact

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    ABSTRACT: A comparative examination of potential differences in selenium (Se) sensitivity was conducted on two sturgeon species indigenous to the San Francisco Bay-Delta. Juvenile green (Acipenser medirostris), recently given a federally threatened status, and white sturgeon (Acipenser transmontanus) were exposed to one of four nominal concentrations of dietary l-selenomethionine (SeMet) (0 (control), 50, 100, or 200mgSeMet/kg diet) for 8 weeks. Mortality, growth performance, whole body composition, histopathology, and Se burdens of the whole body, liver, kidneys, gills, heart, and white muscle were determined every 2 to 4 weeks. Significant (p<0.05) mortality was observed in green sturgeon fed the highest SeMet diet after 2 weeks, whereas no mortality was observed in white sturgeon. Growth rates were significantly reduced in both species; however, green sturgeon was more adversely affected by the treatment. Dietary SeMet significantly affected whole body composition and most noticeably, in the decline of lipid contents in green sturgeon. Selenium accumulated significantly in all tissues relative to the control groups. After 4 and 8 weeks of exposure, marked abnormalities were observed in the kidneys and liver of both sturgeon species; however, green sturgeon was more susceptible to SeMet than white sturgeon at all dietary SeMet levels. Our results showed that a dietary Se concentration at 19.7±0.6mgSe/kg, which is in range with the reported Se concentrations of the benthic macro-vertebrate community of the San Francisco Bay, had adverse effects on both sturgeon species. However, the exposure had a more severe pathological effect on green sturgeon, suggesting that when implementing conservation measures, this federally listed threatened species should be monitored and managed independently from white sturgeon.
    Aquatic toxicology (Amsterdam, Netherlands) 01/2014; 148C:65-73. · 3.12 Impact Factor
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    ABSTRACT: A factorial experiment was conducted to compare the responses of heat shock protein 70 (Hsp70) in seven different tissues of White Sturgeon Acipenser transmontanus and Green Sturgeon A. medirostris after they were exposed to four different stressors. Three White Sturgeon (2.3 ± 0.1 kg [mean ± SE]) and three Green Sturgeon (2.3 ± 0.1 kg [mean ± SE]) were each subjected to one of four different stressors, after which the Hsp70 levels in seven different tissues were measured using Western blot. The four stressors were heat shock, cold shock, air exposure, and food deprivation; and the seven tissues sampled were mucus, heart, liver, gastrointestinal tract, gill, spleen, and white muscle. We also sampled tissues of three White Sturgeon and three Green Sturgeon without any stressor, and measured their Hsp70 levels as a control. We compared Hsp70 responses of the stressed sturgeon with those of the control, which was set at 100%, and found that Hsp70 responses were significantly (P Received August 2, 2012; accepted November 3, 2012
    North American Journal of Aquaculture 01/2013; 75(2). · 0.76 Impact Factor
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    ABSTRACT: Triplicate groups of juvenile green and white sturgeon (average weight of 30 ± 2 g) were exposed to one of four concentrations of dietary methylmercury (MeHg; 0, 25, 50, and 100 mg MeHg/kg diet) for 8 weeks to determine and compare the sensitivity of the two sturgeon species from a histopathological perspective. After 4- and 8-week exposure, histological changes were examined in the kidney, liver, gill, skeletal muscle, and heart muscle of both species using light microscopy. Marked abnormalities were observed in the kidney and liver of both sturgeon species after each exposure period; the abnormalities showed progressive histological alterations in severity with increasing doses and duration of exposure. Renal lesions included tubular epithelium degeneration and necrosis, renal corpuscular disintegration, and interstitial tissue degeneration. The changes observed in the livers of both sturgeon species were glycogen depletion and vacuolar degeneration. In the gill and skeletal and heart muscle of green and white sturgeon fed MeHg-added diets, mild histological changes were observed but did not show pronounced difference between the two species. Although the lowest observed effect concentration in both species was the 25 mg MeHg/kg diet, the histological changes in the kidney and liver were more pronounced at all treatments groups of green sturgeon than those of white sturgeon. The current results on structural changes of kidney and liver (i.e., more severe glycogen depletion and tubular epithelium degeneration in green sturgeon) confirmed our previous results, in that green sturgeon exhibited a higher mortality, lower growth rate, and lower protein, lipid, and energy contents in their whole body than white sturgeon under the same MeHg exposures.
    Aquatic toxicology (Amsterdam, Netherlands) 03/2012; 109:90-9. · 3.12 Impact Factor
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    ABSTRACT: Four 1-week growth trials were conducted to determine the effects of feeding rates on the growth performances of white sturgeon (Acipenser transmontanus) fries 6–9 weeks after initiation of feeding. Six feeding rates with four replications were used in each of the four trials, and the feeding rates were 3.0–8.0, 2.0–7.0, 1.0–6.0 and 1.0–6.0% body weight (BW) per day in 1% increment, respectively. Number of fries per replicate and their initial BW (means ± SEM) were 60, 45, 30 and 30 and 2.8 ± 0.1, 4.5 ± 0.4, 8.5 ± 0.7 and 10.0 ± 0.7 g, respectively. The fries were kept at 18–19 �C and fed a commercial salmonid feed (488 g kg)1 protein and 123 g kg)1 fat). Mortality was low and unrelated to feeding rates. Final body weights, body weight increases, specific growth rates and feed efficiency were significantly (P < 0.05) affected by the feeding rates. Body moisture and lipid contents were significantly affected by feeding rates except body moisture content in trial II. Body protein contents were not affected by feeding rates except in trial III. Broken-line analysis on specific growth rates indicated that the optimum feeding rates were 6.5 ± 0.4, 4.8 ± 0.2, 4.2 ± 0.1 and 3.8 ± 0.2% body weight per day, respectively, for white sturgeon fries 6–9 weeks after initiation of feeding.
    Aquaculture Nutrition 01/2012; · 1.69 Impact Factor
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    ABSTRACT: Triplicate groups of juvenile green and white sturgeon (30 ± 2 g) were exposed to one of the four nominal concentrations of dietary methylmercury (MeHg, 0 (control), 25, 50, and 100mg MeHg/kg diet) for 8 weeks to determine and compare the effects on growth performance and mercury (Hg) tissue burden in the two sturgeon species. Mortality, growth performance as measured by percent body weight increase per day, hepatosomatic index, proximate composition of whole body, and Hg burden in the whole body, gill, heart, liver, kidney, and white muscle were determined to assess the adverse growth effects and bioaccumulation of dietary MeHg in sturgeon. Significantly higher mortality and lower growth rate (p<0.05) were noted in green and white sturgeon fed the MeHg diets compared to the controls. Green sturgeon fed the MeHg diets exhibited earlier and more severe adverse effects compared to white sturgeon. Mercury accumulated in all tissues in a dose-dependent manner regardless of species, and the highest Hg concentrations were found in the kidneys of both species. Dietary MeHg had no significant effect (p>0.05) on the whole body proximate compositions of either sturgeon species. In conclusion, green sturgeon was more susceptible to dietary MeHg toxicity than white sturgeon in our 8-week growth experiment based on the higher mortality and lower growth rate and body energy contents.
    Aquatic toxicology (Amsterdam, Netherlands) 06/2011; 105(3-4):227-34. · 3.12 Impact Factor
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    edited by G. Moniello, 04/2011; , ISBN: 9788890582751
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    edited by G. Moniello, 04/2011; , ISBN: 9788890582752
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    ABSTRACT: The aim of this study was to compare some somatic indexes, chemical-nutritive characteristics and the contents of some metals (Pb, Cu, Cr and Zn) in the whole body and fillet from caught and reared sharpsnout seabream (Diplodus puntazzo). The fish came from three different conditions: reared in marine cages (R), captured in a natural lagoon (L) and in the Mediterranean sea (S). Thirty fish per group, divided into three weight categories (100±15.3, 200±18.7 and 300±20.4g), were used for the trial. Reared sharpsnout seabream showed higher amounts of celomatic fat (3.41%, 2.43%, 0.21%, respectively for R, L and S) and total lipid (13.86%, 11.23% and 5.06% respectively for R, L and S), and lower moisture (64.14%, 65.54%, 71.53%) and protein (17.73, 19.03 and 19.17%) than those caught in the lagoon and sea. The whole body of reared fish contained lower amounts of lead (0.70, 0.75 and 0.97mg/kg, respectively for R, L and S), copper (0.15, 0.38, 0.25mg/kg) chrome (2.19, 3.52, 3.77mg/kg) and higher zinc contents (63.47, 53.42, 47.31mg/kg) than caught fish. Fatty acids from sharpsnout seabream fillets showed a high lipid quality as confirmed also by low values of Thrombogenic index (0.36, 0.30 and 0.22, respectively for L, S, R) and Atherogenic index (0.47, 0.42 and 0.33, respectively for L, S, R). Reared sharpsnout seabream showed lower saturated fatty acid values (26.44%, 32.21%, 34.85%, respectively for R, S, L) and higher oleic acid amount (21.61%, 19.15%, 11.99%, respectively for R, L and S). The subjects captured in the sea had a higher arachidonic acid content (5.44%, 1.76%, 0.59%, respectively for S, L, R). In the weight categories, the 100g subjects, showed higher incidence of viscera (VSI: 4.32%, 3.12% and 2.92%, respectively for 100, 200 and 300g) and liver (HIS: 2.20%, 1.97%, and 1.77%, respectively for 100, 200 and 300g), higher moisture (69.49%, 67.03%, 64.69%) and lower lipid rate (7.64%, 10.18%, 12.32%).
    Italian Journal of Animal Science. 01/2010;
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    ABSTRACT: In order to better define the effect of the sex on the metabolic profile of young ostriches (Struthio camelus domesticus), forty birds were divided into two groups by sex (20 males vs20 females). The animals were fed ad libitumnatural pasture and corn silage. The daily ration was completed by administering 1200 g/head of a commercial concentrate with the following chemical composition expressed as a percentage of dry mat- ter: crude protein 18.8, crude fibre 8.4, ether extract 3.6, ash 7.5. After about 12 h of fasting, in the mor- ning the blood was collected from the wing vein. The following biochemical parameters were determined: glu- cose, cholesterol, triglycerides, lactate (LAC), total protein (TP), uric acid, total bilirubin (Tbil), creatinine (CREA), calcium (Ca), magnesium (Mg), phosphorus (P), natrium (Na), potassium (K), chloride (Cl), iron (Fe), aspartate aminotransferase (AST), alanine aminotransferase (ALT), alkaline phosphatase (AP), choline- sterase (ChE); α-amylase (Amyl), lipase (LIPA); γ-glutamyltransferase (GGT). Sex significantly affected only some haematic parameters: in the females total protein and calcium were higher than in the males (TP, 43.3 vs38.9 g/l, respectively for females and males, P< 0.05; Ca, 2.99 vs2.59 mmol/l, respectively for females and males, P< 0.01). The other haematic parameters did not show signifi- cant differences by sex, and the average values were: glucose (9.87 mmol/l), cholesterol (1.96 mmol/l), triglycerides (1.56 mmol/l), LAC (6.60 mmol/l), uric acid (361 mmol/l), CREA (31.95 µmol/l), Na (144.8 mmol/l), K (3.27 mmol/l), Cl (109.7 mmol/l), P (1.47 mmol/l), Mg (1.10 mmol/l), Fe (9.22 µmol/l), Tbil (9.28 µmol/l), AST (341.3 U/l), ALT (11.42 U/l), AP (75.8 U/l), GGT (10.07 U/l), Amyl (6.97 U/l), LIPA (241.2 U/l), ChE (385.1 U/l). The results of our study, in agreement with previous findings, contribute to enhance the knowledge on the metabolic profile of ostriches in function of the sex.
    Italian Journal of Animal Science. 01/2010;
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    ABSTRACT: The aim of this study was to evaluate the effect of two diets with different protein/fat ratios (P/F) (diet A: P/F 2.26; diet B: P/F 3.36) on the chemical composition, fatty acid profile and some somatic indexes of meagre (Argyrosomus regius). The trial was carried out on two groups of meagre raised in two different sea cages during 15 months. At the end of the production cycle biometric measures as well as chemical-nutritional analysis of the fillets were conducted on 25 fishes per group. Diet A, with a lower P/F, furnished animals with higher percentages of mesenteric fat (0.48 vs 0.41%; P<0.01) and of fillet yield (51.21 vs 48.12; P<0.01). Moreover, the fillets obtained with the diet A showed higher percentage of fat (3.60 vs 2.41%; P< 0.01), lower moisture (74.10 vs 75.42%; P<0.01), lower losses of water under pressure (16.73 vs 20.20%; P<0.01) and after 48 h of refrigeration (3.08 vs 4.23%; P<0.01). The fatty acids profile of fillets was affected by the diet. Diet A resulted in a higher level of saturated fatty acids (26.44 vs 23.17% of total lipid; P<0.01) and a lower percentage of polyunsaturated fatty acids (31.56 vs 36.08%; P<0.01) in the fillet, mainly due to the lower content of linoleic acid (13.63 vs 19.77%; P<0.01). The atherogenic (AI) and thrombogenic (TI) indexes, which resulted very low in the fish of Group B (AI=0.48 vs 0.60, P<0.01; TI=0.33 vs 0.37, P<0.01), together with the low lipid content of meat in both groups, confirmed the very high nutritional quality of meagre fillets.
    Italian Journal of Animal Science. 01/2010;
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    ABSTRACT: In order to study the metabolic profile of ostriches in relation to diet, 40 animals of both sexes were divided equally into two groups and fed two diets ad libitum consisting, on a dry matter basis, of the same commercial concentrate (60%) for the two groups and of corn silage (group A) or alfalfa hay (group B). In the morning, after about 12 h of fasting, blood was collected from the wing vein. The following haematological parameters were determined with an automatic system (Ektachem 250 analyser, Kodak): glucose, cholesterol, triglycerides, lactate (LAC), total protein (TP), uric acid, total bilirubin (Tbil), creatinine (CREA), calcium (Ca), magnesium (Mg), phosphorus (P), sodium (Na), potassium (K), chloride (Cl-), iron (Fe), aspartate aminotransferase (AST), alanine aminotransferase (ALT), alkaline phosphatase (AP), cholinesterase (ChE), alpha-amylase (Amyl), lipase (LIP) and gamma-glutamyltrasferase (GGT). Diet significantly affected some parameters of the metabolic profile. Indeed, owing to the presence of alfalfa hay in the diet, group B showed, in comparison to group A, significantly higher values of uric acid (222.5 vs 387.5 mmol/L, p < 0.01), GGT (8.50 vs 11.3 U/L, p < 0.05), Tbil (8.50 vs 10.7 mmol/L, p < 0.05), Ca (2.41 vs 2.83 micromol/L, p < 0.01), Mg (1.01 vs 1.18 micromol/L, p < 0.05) and K (2.71 vs 3.16 micromol/L, p < 0.01). The levels of creatinine (27.3 vs 32.6 mmol/L, p < 0.05) and AST (344.9 vs 461.4 U/l, p < 0.01) were also higher for group B.
    Tropical Animal Health and Production 05/2007; 39(4):265-70. · 1.09 Impact Factor
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    ABSTRACT: Nella presente comunicazione vengono riportati i risultati di uno studio, condotto su conigli da 35 a 90 giorni di età . Gli animali sono stati divisi in 3 gruppi, di cui uno usato come controllo e gli altri due hanno ricevuto due differenti livelli di β-casomorfina preparata per via sintetica ed utilizzata come additivo alimentare. Su ciascun animale sono stati controllati l'ingestione di alimento, l'accrescimento e l'indice di conversione alimentare da 35 a 70 giorni e da 71 a 90 e nell'intero periodo di accrescimento (da 35 a 90 giorni).