Effect of short-term rotifer enrichment with marine phospholipids on growth, survival, and composition of meager (Argyrosomus regius) larvae

Larval rearing and ongrowing of meager have experienced a great advance during the last years and nowadays this species is considered as one of the most important new species in Mediterranean aquaculture. However, larval nutrition in meager still needs some improvements especially regarding live prey enrichment and fatty acid composition. In this study, a trial for larval rearing of meager (Argyrosomus regius) using different commercial products for rotifer enrichment (Multigain, Red Pepper and concentrated microalgae) with and without phospholipids (PL), and with a different fatty acid composition, especially regarding DHA, have been used to assess the growth and survival of the larvae and check the effect of PLs in larval growth. Lipid class composition was the same among the larvae whereas % DHA was always higher in larvae fed Multigain and Red Pepper enriched rotifers. The dominant fatty acids in the PL of the larvae and PL of the diets were well-correlated and the results suggested a close relationship between the composition of dominant PL fatty acids in the rotifer and in the larvae, especially in the case of DHA and 16:0 that show a high correlation.info:eu-repo/semantics/publishedVersio

Thermal imprinting modifies adult stress and innate immune responsiveness in the teleost sea bream

The impact of thermal imprinting on the plasticity of the hypothalamic-pituitary-interrenal (HPI) axis and stress response in an adult ectotherm, the gilthead sea bream (Sparus aurata, L.), during its development was assessed. Fish were reared under 4 thermal regimes, and the resulting adults exposed to acute confinement stress and plasma cortisol levels and genes of the HPI axis were monitored. Changes in immune function, a common result of stress, were also evaluated using histomorphometric measurements of melanomacrophages centers (MMCs) in the head kidney and by monitoring macrophage-related transcripts. Thermal history significantly modified the HPI responsiveness in adult sea bream when eggs and larvae were reared at a higher than optimal temperature (HT, 22 degrees C), and they had a reduced amplitude in their cortisol response and significantly upregulated pituitary pomc and head kidney star transcripts. Additionally, after an acute stress challenge, immune function was modified and the head kidney of adult fish reared during development at high temperatures (HT and LHT, 18-22 degrees C) had a decreased number of MMCs and a significant downregulation of dopachrome tautomerase. Thermal imprinting during development influenced adult sea bream physiology and increased plasma levels of glucose and sodium even in the absence of an acute stress in fish reared under a high-low thermal regime (HLT, 22-18 degrees C). Overall, the results demonstrate that temperature during early development influences the adult HPI axis and immune function in a teleost fish.project Lifecycle EU-FP7 [222719]FCT- Foundation for Science and Technology [CCMAR/Multi/04326/2013]info:eu-repo/semantics/publishedVersio

Short-term enrichment of microalgae with inorganic selenium and zinc and their effects on the mineral composition of microalgae and marine rotifer Brachionus plicatilis

Rotifers are widely used as a live prey for finfish larvae, although their content in minerals such as selenium and zinc is lower than in fish. In the present study, mixed microalgae (i.e., Isochrysis aff. galbana and Nannochloropsis oculata) were enriched with different amounts of Se and Zn either alone (45, 90, and 135 mg L−1 of Zn, 60, 120, and 180 mg L−1 of Se) or mixed (22.5, 45, and 90 mg Zn L−1 and 30, 60, and 120 mg Se L−1). The content of minerals in the microalgae was analysed after 1 and 3 h enrichment and their effect on the growth and mineral composition of the rotifer. Based on the results, 1 h enrichment time and 90 and 120 mg L−1 of Zn and Se, respectively, resulted in the highest amount of Se and Zn in enriched microalgae. The maximum Zn content was detected in the rotifers fed 90 mg L−1 Zn and 90 mg L−1 Zn +120 mg L−1 of Se, but the maximum Se was observed in rotifers fed with 120 and 180 mg L−1 Se. Thus, Se- and Zn-enriched rotifers can be used as a mineral delivery method to cover marine fish larvae nutritional requirements.info:eu-repo/semantics/acceptedVersio

Understanding the Interaction Effects between Dietary Lipid Content and Rearing Temperature on Growth Performance, Feed Utilization, and Fat Deposition of Sea Bass (Dicentrarchus labrax)

This study was conducted to elucidate the interaction effects of temperature and dietary lipid levels (2 × 2 factorial experiment) on the growth performance, muscle, and liver composition in adult farmed European sea bass (Dicentrarchus labrax). Two groups of fish (190 g; 60 fish per group) were distributed in 12 tanks in triplicates and kept at two different temperature regimes; one starting at 23 °C and then changed to 17 °C for 61 days, and the other starting at 17 °C and then changed to 23 °C for 39 days. Two commercial diets containing both ~44% crude protein but incorporating different dietary lipid levels, 16.5% (D16) and 20.0% (D20) (dry matter (DM)), were fed to the fish to apparent satiation; the type of diet fed to each fish group remained constant throughout the experiment. Final body weight, weight gain, and specific growth rate were significantly higher for the fish group held at 23 °C compared to the fish group at 17 °C (before the temperature changes), while the dietary fat content did not have any profound effect in both groups. Furthermore, the different temperature regimes did not affect muscle or liver composition, but, on the contrary, dietary lipids affected hepatosomatic, perivisceral fat, and visceral indexes. Feed conversion ratio and specific growth rate were not affected by the dietary lipid level. An interaction of temperature and dietary lipid content was observed in daily feed consumption (DFC) and final body weight (FBW).info:eu-repo/semantics/publishedVersio

Lecithin-enriched Artemia combined with inert diet and its effects on reproduction and digestive enzymes of Aequidens rivulatus

The present study investigated the effects of soybean lecithin bioencapsulated in adult Artemia franciscana and unenriched Artemia in combination with an inert diet on digestive enzymes activity and reproductive performance in Aequidens rivulatus (green terror cichlid). Eight hundred and ten fish (3.1 ± 0.2 g) were randomly allotted into glass tank (80 L) and assigned to ten dietary treatments with 5 different levels (0, 25, 50, 75, and 100%) of either lecithin-enriched Artemia (EA) or unenriched Artemia (UA) over a period of 90 days. The amount of total polar lipid increased from 39.2% in the unenriched Artemia to 43.7% in the lecithin-enriched Artemia (P < .05). The fish fed with 50% EA had higher total weight, and total length compared with other groups (P < .05). The peculiar functions of total alkaline proteases, α-amylase, and lipase in green terror increased in the groups fed with lecithin-enriched Artemia, compared to the un-enriched groups (P < .05). The highest total alkaline proteases activity was observed in the fish fed with 75% EA treatment. In comparison to the other groups, fish fed 100 and 0% levels of Artemia replacement had significantly highest and lowest α-amylase activity values, respectively. Concerning reproductive performance, the highest average fecundity, egg diameter, egg weight, fertilization, hatching, and larval survival rates, as well as the lowest time between two spawning episodes, were obtained in fish fed 50% EA. In conclusion, this feeding strategy is advisable for a proper nutritional management of broodfish of green terror cichlid.info:eu-repo/semantics/acceptedVersio

Effects of graded levels of arachidonic acid on the reproductive physiology of Senegalese sole (Solea senegalensis): fatty acid composition, prostaglandins and steroid levels in the blood of broodstock bred in captivity

Previous studies on Senegalese sole (Solea senegalensis) indicated that cultured broodstock (first generation, G1) have lower tissue levels of arachidonic acid (20:4n-6, ARA) than wild counterparts. ARA is metabolized to form prostaglandins (PGs) that are involved in steroid production and follicle maturation in fish. In the present study the effects of different dietary levels of ARA on blood lipid and fatty acid composition, prostaglandin (PGF2&alpha;, PGF3&alpha;, PGE2 and PGE3) levels and plasmatic steroid levels (11-ketotestosterone, 11-KT, testosterone, T and estradiol, E2) in G1 Senegalese sole were studied. For this purpose, 12 groups of ten fish (1:1 male and female), were fed six diets (each diets was fed to two groups) with different dietary ARA levels over nine months (diets A = 0.7, B = 1.6, C = 2.3, D = 3.2, E = 5.0, F = 6.0% ARA). ARA and CHOL levels in blood showed a significant increase in an ARA dose related manner (P &lt; 0.05) whereas EPA and EPA/ARA ratio were reduced. In males, steroid (11-KT and T) levels increased significantly with increasing dietary ARA in a dose dependent manner, whereas in females E2 did not show any change related to dietary ARA content. Plasma concentration of 3-series PGs (i.e., PGE3 and PGF3&alpha;) were reduced in parallel to increased ARA levels in blood (P &lt; 0.05) and levels of PGs 3-series were always higher than 2-series PGs (PGE2 and PGF2&alpha;). In conclusion there is an effect of dietary ARA on steroid production of Senegalese sole males, which might have important consequences in the reproduction of cultured fish

Adsorption of Methylene Blue and Tetracycline by Zeolites Immobilized on a PBAT Electrospun Membrane

The detection of emerging contaminants in bodies of water has steadily increased in recent years, becoming a severe problem threatening human and ecosystem health. Developing new materials with adsorption properties to remove these pollutants represents an important step toward a potential solution. In this paper, a polybutylene adipate terephthalate (PBAT) nanofibrous membrane incorporating clinoptilolite zeolite was developed and its excellent performance in removing tetracycline (TC) and methylene blue (MB) from water was demonstrated. The composite membrane was prepared in two steps: firstly, a homogeneous dispersion of clinoptilolite (1 wt% respect to polymer) in a PBAT solution (12.6 wt%) was electrospun; secondly, the electrospun membrane was subjected to an acid treatment that improved its wettability through the protonation of the surface silanol groups of clinoptilolite. The resulting membrane was hydrophilic and showed higher adsorption for TC (800 mg/g) and MB (100 mg/g), using a low dose (90 mg/L) powdered zeolite. The maximum removal capacity was obtained at neutral pH, being the cation exchange reaction the main adsorption mechanism. Pseudo-second-order kinetics and Henry’s law agree well with the proposed chemisorption and the high affinity of TC and MB for the adsorbent. The material can be reused after the removal process without generating additional contamination, although losing some effectivity.Fil: Picon Borregales, David Emmanuel. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Ciudad Universitaria. Instituto de Física de Buenos Aires. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Instituto de Física de Buenos Aires; Argentina. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Departamento de Física. Laboratorio de Polímeros y Materiales Compuestos; ArgentinaFil: Vergara Rubio, María Alicia. Universidad Nacional de San Martín. Instituto de Investigación e Ingeniería Ambiental. - Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Parque Centenario. Instituto de Investigación e Ingeniería Ambiental; Argentina. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Departamento de Física. Laboratorio de Polímeros y Materiales Compuestos; ArgentinaFil: Estevez Areco, Santiago. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Tandil. Centro de Investigaciones en Física e Ingeniería del Centro de la Provincia de Buenos Aires. Sede Olavarría del Centro de Investigaciones en Física e Ingeniería del Centro de la Provincia de Buenos Aire. Universidad Nacional del Centro de la Provincia de Buenos Aires. Centro de Investigaciones en Física e Ingeniería del Centro de la Provincia de Buenos Aires. Sede Olavarría del Centro de Investigaciones en Física e Ingeniería del Centro de la Provincia de Buenos Aires; Argentina. Universidad Nacional del Centro de la Provincia de Buenos Aires. Facultad de Ciencias Exactas. Instituto de Física de Materiales; ArgentinaFil: Cerveny, Silvina. Consejo Superior de Investigaciones Científicas; España. Universidad del País Vasco; EspañaFil: Goyanes, Silvia Nair. Universidad de Buenos Aires; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Ciudad Universitaria. Instituto de Física de Buenos Aires. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Instituto de Física de Buenos Aires; Argentina. Centro de Física de Materiales; España. Donostia International Physics Center; Españ

Dietary modulation of arachidonic acid metabolism in senegalese sole (Solea Sengalensis) broodstock reared in captivity

Previous studies have shown higher levels of arachidonic acid (20:4n-6, ARA) in testis, liver, and muscle of wild Senegalese sole (Solea senegalensis) compared to fish reared in captivity (first generation, G1). The present study was conducted to establish the optimal level of dietary ARA for G1 Senegalese sole broodstock, using as a reference the fatty acid profile of wild broodstock (gonads, liver and muscle). A total of 120 Senegalese sole broodstock were randomly distributed into 12 tanks (1:1 male and female) and fed in duplicate with six experimental diets containing increasing amounts of ARA (0.7%, 1.6%, 2.3%, 3.2%, 5.0%, and 6.0 % of total fatty acids) for 9months. The relative ARA levels in liver, muscle and male and female gonads at the end of the feeding period increased in a dose dependent manner. Dietary ARA was mainly incorporated and stored in testis or ovary, followed by liver and muscle. Fish fed 2.3% and 3.2% ARA showed no differences in the ARA content of testis, ovary and liver when compared to wild fish. In male fish, a significant increase in the levels of 22:4n-6 and 22:5n-6 fatty acids was also observed, which was consistent with the up-regulation of fatty acyl elongase (elovl5) and desaturase (d4fad) transcript levels in the liver of fish fed 0.7%, 2.3% and 6% ARA. These results suggest that dietary inclusion of 3.2% ARA during periods shorter than 9months, or of 2.3% ARA for prolonged periods, can maintain optimal levels of tissue ARA in captive Senegalese sole broodstock. In addition, the data indicate that male Senegalese sole is able to elongate and desaturate ARA to 22:4n-6 and 22:5n-6, suggesting that these fatty acids may be important for male reproduction