Shape ontogeny and variation in the sharpsnout seabream, Diplodus puntazzo (Cetti 1777)

Shape ontogeny of Diplodus puntazzo was studied during the larval and metamorphosis phase (2.6–33.0 mm total length (TL)) by means of geometric morphometrics. Additionally, shape comparison was performed between newly settled wild individuals of D. puntazzo (11.0–18.0 mm TL) and reared of the same TL range. Results clearly demonstrated that shape ontogeny of D. puntazzo is not continuous during the studied period, but it is characterized by the presence of two inflection points (at 6.2 and 11.4 mm TL), which define three phases of significantly different rates of shape development (P<0.05). Spline diagrams demonstrated that shape ontogeny mainly correlated with the development of fins, caudal peduncle, snoot and the ventral abdominal profile. Concerning the comparison of reared fish with wild fish, morphometric analysis revealed a significant effect of fish origin on the shape of D. puntazzo (Wilks' λ=0.147, P<0.001). Shape differences between the two populations were mainly demonstrated at the caudal peduncle and at the ventral profile of the abdominal area. Combined with the results of shape ontogeny, spline diagrams showed that shape differences between the two populations were related to the comparatively more advanced ontogenetic state of reared fish, at the studied size range.     

Morphoecology in larval fin-fish: a new candidate species for aquaculture, Diplodus puntazzo (Sparidae)

This study was aimed to acquire information ontrophic behavior of Diplodus puntazzolarvae and juveniles, by studing theontogenetic sensory development, except vision.D. puntazzo specimens were observed usinga scanning electron (n = 67) and a lightmicroscope (n = 7). The results concerned fourontogenetical stages of sharpsnout seabream:larval, post-larval, transitional, and juvenilestages. The yolk-sac larval stage was notdetected as the smallest larvae at our disposal(3.1 mm TL; 2nd day from hatching) showedno external appearance of the yolk. During thelarval stage (3.1–4.7 mm TL), sharpsnoutseabream is equipped with free neuromasts andolfactory ciliated receptor cells. In thepost-larval stage (5–28.6 mm TL), mechano- andchemo-reception is implemented: the inner andouter taste buds differentiation, the nasalformation, the lateral line system canalizationoccur. The precocious differentiation ofchemo-receptors makes post-larvae particularlysensitive to the organoleptic properties ofadministered preys. D. puntazzo, at theend of this phase, could be considered ajuvenile (complete squamation is acquired),except for the mouth and pharyngeal teeth.During the subsequent phase (`transitional'),in fact, eight chisel-type and two lateralseries of molar-like teeth progressivelysubstituted the conical ones on each jaw, andthree different types of teeth on the upper andlower pharynx differentiated. So, the juvenilephase is reached in individuals longer than58 mm TL.     

Dietary self-selection in sharpsnout seabream (Diplodus puntazzo) fed paired macronutrient feeds and challenged with protein dilution

Macronutrient selection and responses to dietary protein dilution were investigated in 95-g sharpsnout seabream, an omnivorous fish species of interest for Mediterranean aquaculture. Five groups of 18 sharpsnout seabream were distributed among circular 450-l tanks and allowed to self-feed from 3 feeders each of which distributed feeds composed of different pairs of macronutrients: PC (75% protein, 25% carbohydrate), PF (75% protein, 25% fat) or FC (50% fat, 50% digestible carbohydrate). Regardless of self-feeders position, the fish composed a diet containing 63% protein, 19% fat and 18% carbohydrate. When the protein-containing diets (PC and PF) were diluted 50% with cellulose, the fish increased their food intake to compensate for the energy dilution (170 kJ/kg BW/day vs. 168 kJ/kg BW/day after dilution), and dietary composition (63% protein, 16% fat and 21% carbohydrate) did not change significantly. These results demonstrate that sharpsnout seabream can select from incomplete diets to compose a balanced diet, and the fish are also able to compensate for a dietary dilution to regulate both energy intake and the relative proportions of macronutrients.     

The kinetic profile of oxolinic acid in sharpsnout sea bream, Diplodus puntazzo (Cetti 1777)

The pharmacokinetics of oxolinic acid (OA) were investigated after a single intra‐vascular injection (20 mg kg^?1 fish) in sharpsnout sea bream (90 g), a promising new euryhaline species for Mediterranean fish farming. The distribution half‐life (t_1/2α) and the elimination half‐life (t_1/2β) of OA were calculated to be 0.4 and 10 h respectively. The apparent volume of distribution at steady‐state (V_d(ss)) and total clearance rate (CL_T) of the drug were found to be 2.1 L kg and 0.2 L kg^?1 h^?1 respectively. The bioavailability (F%) of OA following oral administration (40 mg kg^?1 fish) was estimated to be 15%. The results indicate a rapid distribution and elimination of the drug, moderate tissue penetration, but low absorption in sharpsnout sea bream. The kinetic profile of OA found in this species is comparable with that observed in another well‐known sparid, gilthead sea bream.     

Chronic ulcerative dermatopathy in cultured marine fishes. Comparative study in sharpsnout sea bream, Diplodus puntazzo (Walbaum)

Chronic ulcerative dermatopathy (CUD) also known as chronic erosive dermatopathy, hole-in-the-head, head and lateral line erosion syndrome (HLLE) and lateral line depigmentation (LLD) is a chronic disease of unknown aetiology that affects the lateral line canals of the head and the trunk of various fish species. It has been described only in freshwater species although there are reports that it also affects marine fish. Here, we describe the disease in cultured sharpsnout sea bream using histology and scanning electron microscopy and identify several marine species as CUD sensitive. The results of this study correlate the development of the disease with the use of borehole water, indicating that the aetiology is probably associated with water quality rather than nutritional imbalance or infectious agents.     

Mono- and duoculture of juvenile sharpsnout seabream Diplodus puntazzo (Cetti) and gilthead seabream Sparus aurata L. in a recirculated water system

Although the growth of intensively reared sharpsnout seabream Diplodus puntazzo (DP) has been suggested to improve in duoculture with gilthead seabream Sparus aurata (SA), the stocking ratio for most effective duoculture rearing has not been investigated. For this purpose, juvenile D. puntazzo (1.68±0.011 g) and S. aurata (1.43±0.007 g) were reared in duplicated groups of 165 specimens each, in two monoculture (100% DP, 100% SA) and four duoculture combinations (80% DP–20% SA, 60% DP–40% SA, 40% DP–60% SA, 20% DP–80% SA) for 96 days under recirculated water system conditions. Both species exhibited the highest growth when stocked at 20% and the poorest growth when stocked at 80%. For each species, no major differences for coefficient of weight variation and carcass proximate composition were detected. As the percentage of stocked S. aurata increased, D. puntazzo aggressiveness and weight variability of whole population were reduced, while total biomass, food consumption and food conversion ratio were increased. The results obtained are discussed in relation to fish behaviour and social interactions. From the fish farming point of view, it is indicated that under the present experimental conditions, juvenile S. aurata should be reared in monoculture and D. puntazzo in duoculture 40% DP–60% SA.     

A study of the pattern of digestive enzymes in Diplodus puntazzo (Cetti, 1777) (Osteichthyes, Sparidae): evidence for the definition of nutritional protocols

The digestive enzymes (proteases, carbohydrases and lipases) present along the alimentary tract of juveniles and adults of Diplodus puntazzo were studied. The data obtained showed a different distribution of the enzymatic activities in the different parts of the alimentary tract. Levels of enzymatic activity in the adults were higher than those measured in juveniles, suggesting that adults have a greater ability to digest larger pieces of food. The enzymatic pattern of D. puntazzo justifies its omnivorous habit and suggests an high potential for digesting vegetable polysaccharides. The results of this study suggest the need to adapt the diet to the digestive potential of this new farming species, thus contributing to the attainment of a product that is qualitatively more similar to the wild one.     

Meristic character counts and incidence of skeletal anomalies in the wild Diplodus puntazzo (Cetti, 1777) of an area of the south-eastern Mediterranean Sea

The sharpsnout seabream (Diplodus puntazzo, Cetti 1777) is a species rarely found in coastal areas of Sicily, but is important in Mediterranean aquaculture. In order to detect the number of meristic characters and the main types of body deformation, 588 specimens of sharpsnout seabream were collected from a coastal zone of south-east Sicily (Licata, AG—Italy). Different sized classes were examined and the relationship between size and the number of meristic characters (number of fin rays) was found. The number of vertebrae, anal fin hard rays and dorsal fin hard rays was constant and did not vary with size. Seventeen types of skeletal and fin anomalies were observed, but no grave anomalies were found, such as the absence of a swimbladder, lordosis, kyphosis and calculi in the terminal tract of the urinary duct. The most prevalent anomalies were associated with the fins, especially E7 (pectoral fin rays), F7 (anal fin rays) and I7 (dorsal fin soft rays). There was no correlation between frequency of anomaly and size class. The malformation index was 4.54.     

不同养殖模式对尼罗罗非鱼（Oreochromis niloticus）生长、免疫性能及水质的影响

为探讨循环水养殖模式(RAS组)和池塘养殖模式(池塘组)对尼罗罗非鱼生长、免疫性能及水质影响的变化规律,开展了为期8周的养殖试验。结果表明：(1)RAS组中鱼体增重率(WGR)(597.36±169.79)显著高于池塘组(470.98±142.99)(P < 0.05),但饲料转化率(FCE)(1.17±0.02)却显著低于池塘养殖系统(1.47±0.03)(P < 0.05)。特定生长率(SGR)和肥满度(CF)也高于池塘养殖系统,但差异不显著(P > 0.05);(2)在第4周和第8周分别测定了鱼体胃和肠中消化酶活性显示,第4周时,RAS组中肠蛋白酶活性值(1387.56±278.43)显著高于池塘组(1129.99±382.67)(P < 0.05);第8周时,肠脂肪酶活性(18.11±4.28)显著高于池塘组(12.89±8.00)(P < 0.05);(3)在第4周和第8周分别测定了鱼体肝胰脏、头肾和血清中碱性磷酸酶(ALP)、溶菌酶 (LSZ)和总超氧化物歧化酶(T-SOD)活性,显示整体上RAS组免疫性能低于池塘组;(4)每周测定水体氨态氮和亚硝态氮含量显示,RAS组氨态氮维持在0.0067 ~ 0.0212 mg / L区间内,亚硝态氮含量位于0.0027 ~ 0.0087 mg / L范围内,均低于池塘组。     

Melanosis Inhibition and SO2 Residual Levels in Farmed Tiger Shrimp (Penaeus monodon) Following Different Sulfite-Based Treatments

Inhibition of melanosis was studied in farmed tiger shrimp (Penaeus monodon) treated with different concentrations of sulfite-based formulations. Treatments, applied by dipping for 0.5 h, were carried out immediately following the harvest. Melanosis, sensory quality, and the level of SO₂ residues in the muscle were determined in a selection of the most effective treatments. The minimum dose to avoid melanosis and keep quality for at least 10 days was found to be 30 g kg^?1. With all the treatments, the statutory limit of 0.3 g kg^?1 SO₂ in the edible part was not exceeded by any of the samples analyzed.     

Restructured Gel Products from Farmed Meagre (Argyrosomus regius) Muscle: Effect of Low Salt Levels,Psyllium Fiber,and Chilled Storage

New heat-induced gel products prepared from farmed meagre (Argyrosomus regius) and psyllium dietary fiber (DF; up to 4.0%, w/w) with reduced salt content (from 2.5 to 1.0%, w/w) were studied. The effect of chilled storage time (15 days vs. 1 day) was also measured. Psyllium DF worsened breaking force and deformation as well as springiness, but it did not affect the remaining textural properties and improved water holding capacity (WHC). Salt reduction from 2.5 to 1.0% (w/w) decreased breaking force and deformation, cohesiveness, and WHC. The textural, color, and WHC properties of heat-induced meagre gels were unaffected by chilled storage time. Results pointed to the feasibility of using psyllium DF addition up to 4.0% (w/w) as a strategy not only to improve nutritional value of the gel products, but also to countervail some of the negative effects of a lower salt content.     

The Effect of Capture and Handling Stress on Plasma Steroid Levels and Gonadal Condition in Wild and Farmed Snapper Pagrus auratus (Sparidae)

The effects of stress on reproductive steroids and the developing oocytes were investigated in female wild snapper Pagrus auratus caught by trap, 5-yr-old snapper caught as juveniles and reared in captivity, and 2- and 3-yr-old hatchery-reared snapper. Fish were confined post-capture for 1, 6, 24, 48 or 168 h. Stress resulted In an increase in plasma cortisol and concomitant decreases in 17β-estradiol and testosterone. In addition, there was an increase in the incidence of ovarian atresia. These results confirm that both wild and hatchery-reared snapper are highly susceptible to stress-induced impairment of reproduction.     

Physicochemical and Reactive Oxygen Species Scavenging Properties of Collagen and Collagen Hydrolysates from Farmed Globefish (Fugu rubripes) Bone

Globefish (Fugu rubripes) bone collagen (GBC) was isolated and characterized. Electrophoresis and Fourier transform infrared (FTIR) spectra indicated that GBC was high-purity type I collagen with an intact triple-helical structure. Amino acid analysis revealed that GBC contained higher glycine content (364 residues/1,000 residues) than that of other fishery bones, and the imino acid content was 189 residues/1,000 residues. The denaturation temperature (T_d) of GBC was 27.1°C. GBC displayed a rapid fibril-forming rate and well-defined fibril morphology in vitro. Globefish bone collagen hydrolysates (GBCH) were optimized by neutral protease through response surface methodology (RSM) with the highest hydroxyl radical (?OH) scavenging capacity. The optimal hydrolysis condition was a reaction temperature of 48.4°C, time of 120 min, and enzyme/substrate ratio of 2520 U/g. Three fractions were collected by ultrafiltration, and the fraction GBCH-III (Mw<1 kDa) possessed the strongest ?OH scavenging ability. Reactive oxygen species (ROS) scavenging capacities were evaluated with two model systems: ?OH and nitric oxide (NO?). The ROS scavenging capacities increased in a dose-dependent manner. GBCH-III proved to be a more effective ?OH scavenger than reduced glutathione (GSH). These findings demonstrated that GBC and GBCH have potential as an alternative source of collagen-derived materials for use in pharmaceutical, nutraceutical, and cosmetic industries.     

Evaluation of dietary protein and lipid requirements of two-banded seabream (Diplodus vulgaris) cultured in a recirculating aquaculture system

The objective of this study is to investigate the effects of dietary protein and lipid levels on the growth performance and bioeconomic benefits of two-banded seabream (Diplodus vulgaris) juveniles, a candidate species for aquaculture sector. Eight experimental diets were formulated with four protein (50, 45, 40 and 35 %) levels for each of the two lipid levels (15 and 10 %). Triplicate groups of juvenile fish with an average initial body weight of ~3.64 g were reared in a recirculating aquaculture system and hand fed twice a day until satiation for a period of 60 days. In the experiment, no difference in survival rate was found between the different groups. Relative growth rate (RGR), specific growth rate (SGR), feed conversion ratio (FCR) and daily feed intake were not significantly affected by increasing protein and/or lipid treatments in this present study. However, the RGR, SGR and FCR values showed slightly better efficiency in the experimental group (35/15) fed with lower protein content (35 %) and higher lipid level (15 %) compared with those fed other diets. According to bioeconomic analyses results, the diet with the 35 % protein and 15 % lipid generated the best profit. The results suggest that two-banded seabream can be accepted as a promising alternative species for the aquaculture industry and optimum growth of two-banded seabream fingerlings can be obtained when they are fed a diet containing 35 % crude protein and 15 % crude lipid.     

七带石斑鱼和云纹石斑鱼幼鱼在封闭循环水条件下的生长特性

观测研究了七带石斑鱼(Epinephelus septemfasciatus)幼鱼和云纹石斑鱼(Epinephelus moara)幼鱼在封闭式循环养殖系统中的生长特性,用SPSS 17.0软件中的Curve Estimation对相关数据进行模型分析与参数估计。结果表明,经过122 d的养殖,七带石斑鱼幼鱼平均体质量由(114.836±25.343)g增加到(213.861±38.604)g,相对增长率为0.707%,全长(TL)与养殖时间(t)的函数关系式为TL=-0.006t3+1.622t+13.954,体质量(W)与体长(BL)的关系式为W=0.436BL2.055;云纹石斑鱼幼鱼平均体质量由(79.620±13.007)g增加到(238.086±46.307)g,相对增长率为1.631%,全长(TL)与养殖时间(t)的函数关系式为TL=-0.013t2+2.008t+11.540,体质量(W)与体长(BL)的关系式为W=0.018BL3.083。两种幼鱼丰满度生长差异不显著(P0.05),都保持在2.2-3.4之间。     

卤水兑地下淡水中国对虾精养高产技术

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