Search

The green mandarin fish, Synchiropus splendidus , is a popular marine aquarium species, but currently sourced largely from the wild. To establish a reliable feeding regime for its larvae in captivity, a series of experiments were conducted. In the 1st experiment, newly hatched larvae were fed either unenriched rotifers (ss-type), rotifers enriched with Algamac 3000 or a mixture of commercial enrichments. An unfed control was also set up, which suffered a total mortality by 5 day post-hatching (DPH). All feeding treatments had similar low survival (<3.3%) by 11 DPH, suggesting rotifer enrichment bore little benefits. In the 2nd experiment, larvae were fed enriched and unenriched rotifers at 10 mL −1 and a mixed diet of 2 copepods (nauplii and copepodites of Parvocalanus crassirostris ) + 8 rotifers mL −1 . The copepods co-feeding with rotifers treatment showed dramatically improved survival (50%) as compared to rotifer feeding only treatments (≤5.6%) by 12 DPH ( p  < 0.01). The copepods + rotifers diet also generated significantly larger larvae ( p  < 0.01). The 3rd experiment aimed at determining the minimum quantity of copepods required for co-feeding with rotifers. Five treatments of copepods provided at 0, 0.1, 0.5, 1.0 and 2.0 mL −1 with rotifers making up the rest of a total of 10 prey mL −1 were set up. Larval survival to 11 DPH were significantly higher in the 2 copepods + 8 rotifers mL −1 and 1 copepods + 9 rotifers mL −1 treatments (52% and 48%) than other treatments (<19%) while no significant difference was detected between the two treatments. Larval growth was not significantly different among all copepod feeding treatments, even copepods were provided at only 0.1 mL −1 , and they were all significantly higher than the rotifer feeding only treatment ( p  < 0.05). Our results demonstrated the importance of copepods as prey for rearing early larval S. splendidus and suggested that they should be co-fed at least 1.0 mL −1 to ensure good survival. [ABSTRACT FROM AUTHOR]

The inexistence of nutritionally adequate diets in paralarval rearing is the main bottleneck for commercial production of the common octopus Octopus cf. vulgaris. We report the feeding behavior of O. vulgaris Type II paralarvae fed on Artemia sp (0.1 individual. mL-1) nauplii enriched with microalgae Isocrysis galbana and Pavlova lutheri microalgae from 0 to 7 Day After Hatching (DAH).; metanauplii enriched with microalgae and DHA SELCO® lipid emulsion from the 8 DAH. The paralarvae showed active swimming and predation by the 14 DAH, feeding in the most superficial portion of the water column. From the 15 DAH, the paralarvae remained near the bottom and there a decrease in the consumption of artemia was observed. The mortality observed from the 18 DAH and mass mortality of paralarvae on 20 DAH can be attributed mainly to the nutritional composition of the diet. Studies analyzing the biochemical composition and ontogeny of the digestive system during the early life stages should shed some light on the running for an appropriate feeding protocol to the paralarval rearing. [ABSTRACT FROM AUTHOR]

Abstract: Adequate enrichment of live prey like Artemia, naturally deficient of essential highly unsaturated fatty acids (HUFA), such as docosahexaenoic acid (22:6n‐3, DHA), is critical for the rapidly developing tissues, survival, normal development and production of good‐quality fingerlings. The aim of the study was to evaluate the effects of a pulse (10–30 dah) of Shewanella putrefaciens Pdp11 (2.5*107 cfu/ml) using Artemia metanauplii as live vector, on its proper lipid profiles and resultant Solea senegalensis body composition and performance. Probiotic administration significantly increased total lipids and specifically n‐3 HUFA levels in Pdp11‐enriched Artemia. The live prey lipid modulation was also reflected in the total lipid contents and fatty acid profiles of Pdp11 sole specimens, which achieved a higher growth performance. A fatty acid multivariate principal component analysis confirmed a neat separation of two groups corresponding to Control and probiotic fish for each age sampled (23, 56, 87 and 119 dah). In addition, a further SIMPER analysis highlighted that the Pdp11 Artemia effect on sole lipid profile was different for each fatty acid and was gradually diluted with age. Results suggest an ability of Pdp11 strain to produce n‐3 HUFA as an effective tool for fish marine larviculture optimization. [ABSTRACT FROM AUTHOR]

Abstract: The study investigated the combined effect of weaning from live feed to a commercial dry pellet at 10, 15, 20, 25 or 30 days posthatching (dph) and co‐feeding for 1, 3 or 6 days on survival and growth of Coregonus peled larvae. Additional groups fed only live Artemia sp. nauplii (ART), and only Biomar LARVIVA ProWean 100 (DRY) were included. A final survival rate of 66.4%–85.5% was observed in groups weaned after 20 dph. Final body weight (BW) and total length (TL) were significantly lower in groups weaned at 10 and 15 dph, regardless of the duration of co‐feeding. Larvae reached 29–37 mg BW and TL of 17.7–19.0 mm in groups weaned at 20, 25 and 30 dph. The recommended minimum duration of feeding with live food, based on these results, is 20 days. Based on the significantly higher yield of larvae weaned after 20 dph irrespective of co‐feeding duration, it can be concluded that abrupt weaning to dry food after 20 days of feeding with live prey can provide adequate production while reducing the effort and costs associated with live feed. [ABSTRACT FROM AUTHOR]

In this study, the aim was to establish a protocol for first feeding of diploid and triploid yellowtail tetra Astyanax altiparanae in laboratory conditions. The fry were fed with five different diets: (i) Artemia franciscana nauplii, (ii) plankton, (iii) dry food, (iv) Artemia franciscana nauplii + plankton, and (v) Artemia nauplii + plankton + dry food. Additionally, the growth and survival rates of diploid and triploid individuals were also evaluated. On day 10, the length of the fish between the treatments differed significantly ( p = .0001) and ranged from 4.07 ± 0.06 mm (dry food) to 8.50 ± 0.64 mm (plankton + Artemia). The sizes of the fish increased with time, except for the fish fed with dry food. The survival rates were similar for the fish fed with the four diets and ranged from 80.7 ± 5.4% (dry food + plankton + Artemia to 92.0 ± 1.6% (plankton + Artemia), but differed from the fish fed with dry food (17.7 ± 5.8%, p = .0017). Diploids and triploids did not present differences on day 0 ( p = .2252) and on day 10 ( p = .4844) when the fish presented 6.77 ± 0.25 mm and 6.54 ± 0.15 mm respectively. Survival of diploids (87.3 ± 5.13%) and triploids (74.67 ± 2.30%) were also similar ( p = .0285). These data are innovative and useful for establishing protocols for this species in both academic and applied sciences. [ABSTRACT FROM AUTHOR]

This research aimed to verify the influence of the photoperiod on the performance and survival piabanha-of-Pardo (Brycon vonoi) larvae. Piabanha-of-Pardo larvae 24 hours post-hatch, with body weight of 2.44 ± 0.02mg, and total length of 7.82 ± 0.46mm, were subjected to five different photoperiods: 0L:24D, 6L:18D, 12L:12D, 18L:6D and 24L:0D (871.12 ± 92.65 lux). Daily, the water temperature, dissolved oxygen (DO), percentage of oxygen saturation, pH, and water conductivity were monitored, and presented similar water quality values among tanks with distinct photoperiods, and within the range considered appropriate for the genus Brycon larvae. Piabanha-of-Pardo larvae have better productive performance and survival rate at longer photoperiods, over 6 hours of light and below 12 hours of light per day. The 9L:15D photoperiod, specified by the derived equation, is indicated for the piabanha larviculture, but researches with the species and the photoperiod need to be better studied. [ABSTRACT FROM AUTHOR]

Catfish farming constitutes about 75% of total U.S. finfish aquaculture production, for which the channel catfish female (Ictalurus punctatus) × blue catfish male (I. furcatus) hybrid accounts for nearly 60% of the harvest. Current hatchery technology to produce hybrids is labor intensive and requires the sacrifice of males. This is expensive and time-consuming, as blue catfish males require 4 to 7 years to mature. Sperm, even from mature fish, are often of low quality and quantity and do not necessarily give high fertility and hatch. Therefore, paternal gametes should be used sparingly, using the minimum quantity of sperm for fertilization, while maximizing offspring production. This is particularly important when using cryopreserved cells, as each males' sperm is in limited supply. To optimize the use of available sperm cells, the objectives of this study were to (i) compare sperm swimming kinematics and sperm health metrics before and after cryopreservation; (ii) determine the minimum quantity of frozen-thawed sperm required to maximize hatching success; and (iii) decipher how early offspring development is affected when eggs are sired with fresh and frozen-thawed sperm. Sperm kinematics were evaluated by computer-assisted sperm analysis, while health metrics (i.e., viability, oxidative stress, DNA fragmentation) were assessed using fluorescent imaging and flow cytometry. Over 2 spawning seasons, eggs from 18 females were collected and fertilized using cryopreserved sperm from 36 males at 10 sperm-to-egg ratios (ranging from 1.0 × 104 to 9.0 × 105 sperm per egg). Embryos sired with fresh and frozen-thawed sperm were then incubated under common environmental conditions and growth performance was documented over 40 days post-hatch. Generally, sperm kinematic traits [curvilinear velocity (VCL), motility, progressive VCL, and progressive motility] and health metrics (cell membrane viability, oxidative stress, and DNA fragmentation) declined after cryopreservation. Despite this decrease in sperm quality, hatching success using cryopreserved sperm was high, but dependent on the sperm-to-egg ratio. For instance, at ratios of 1.0 × 104 to 5.0 × 104 sperm per egg, hatch increased from 18.0% ± 8.5 to 43.9% ± 8.2. Adding >5.0 × 104 sperm per egg had no significant effect on hatching success. Furthermore, there were generally no differences in morphology or deformity rates in offspring sired with cryopreserved sperm, compared to a fresh control. These data improve understanding of frozen-thawed sperm quality for blue catfish to improve reproductive sustainability and reduce production costs. • Develop in vitro fertilization techniques using cryopreserved sperm in blue catfish. • Sperm kinematic traits and health metrics declined after cryopreservation. • Adding >5.0 × 104 frozen-thawed sperm per egg had no impact on hatching success. • Generally, no decline in offspring performance when sired with frozen-thawed sperm. • Cryopreservation viable option for catfish farmers to improve hatchery production. [ABSTRACT FROM AUTHOR]

Shrimp culture systems are being affected by bacterial diseases particularly Vibrios. Use of therapeutic agents in shrimp culture has lead to the resistance among aquatic bacteria. Accordingly, health management becomes of major importance in aquaculture. Under this situation, developing bio-inhibitors from natural marine resources which are most appropriate, which is considered as an unmatched reservoir of several biological products. Molecular docking is suited to a major approach in structural biology and computer-assisted drug design against the proteins of disease-causative agents. In the present study, marine macroalga Kappaphycus alvarezii was used for developing inhibitors against bioluminescence disease-causing pathogenic bacteria Vibrio harveyi. K. alvarezii was collected from the Mandapam, Tamil Nadu, India. Ethyl acetate based extract of K. alvarezii was tested against the growth and virulence factors of V. harveyi during Penaeus monodon larviculture. Further K. alvarezii extract was subjected to GC–MS analysis to identify the biomolecules. The homology modelling of the virulent protein, hemolysin of V. harveyi was designed during this study. Hence, it was aimed at molecular docking against the biomolecules identified from K. alvarezii extract. During shrimp larviculture, the extract of K. alvarezii (200 μg mL−1) exhibited a reduction on Cumulative Percentage of Mortality (29.70 %) in postlarvae against the challenge of V. harveyi infection. Among the compounds docked, an inhibitory effect was observed based on docking scores and were found the highest binding affinity/inhibiting activity in Cyclotetracosane with the least energy required with a docking score of binding energy −7.66 kcal/mol, inhibition constant 0.002 mM and intermolecular efficiency −0.32 kcal/mol. Using statistical analysis, significant differences (p < 0.05) were observed between the growth and virulence factors of V. harveyi during shrimp larviculture trials. While considering these findings, it was determined that K. alvarezii extract can be replaced as an alternative bio-agents protecting against infections caused by V. harveyi and possibly other aquatic pathogenic bacteria in shrimp farming systems. • Isolation of V. haveryi bacteria from infected larviculture tanks • Seaweed K. alvarezii collection, crude extract preparation by cold extraction method, estimation of MIC and MBC against V. harveyi • Gas Chromatography and Mass Spectrometry (GC–MS) analysis of K. alvarezii extract and found bio-inhibitors • Bio-inhibitors/ligand molecule data preparation using PyMOL (0.99rc6) software for molecular docking • Homology modelling of V. harveyi hemolysin protein by Phyre2 software • Hemolysin protein preparation and actives site prediction for docking studies • Molecular docking of ligand molecules of K. alvarezii with hemolysin protein and evaluated the docking scores were obtained • Prediction of drug-likeness of the biomolecules/ ligand using online software SwissADME web tool • Evaluating of K. alvarezii extract against V. harveyi during P. monodon larviculture to find out the cumulative percentage of mortality • Effects of K. alvarezii extract against growth and virulence factors of V. harveyi during P. monodon larviculture • Statistical analysis of data and interpretation and found the significant level of the study [ABSTRACT FROM AUTHOR]

This study evaluated the effects of larval densities, cultured in flow-through system, in the yield and quantity of larvae. The first experiment compared the larval yield of a flow­through system (80 larvae mL-1) and a batch system (8 larvae mL-1), which resulted in a higher yield and number of larvae in the flow­through system, after 23 days. The second experiment compared two larval densities (20 and 45 larvae mL-1) in flow­through system. The densities affected the yield after 15 and 23 days and the larvae final quantity after all tested times (8, 15, and 23 days). After 23 days of larviculture, the yield was highest for 20 larvae mL-1 and the larval number for 45 larvae mL-1. The third experiment also compared two larval densities (100 and 150 larvae mL-1) in flow­through system. The larvae densities did not affect the yield and number of larvae for all tested times (8, 15, and 23 days). In general, the yield has reduced at higher larval densities. Therefore, considering the number of suitable larvae for settlement, the flow-through system was more efficient than the static system. However, in general, we observed reduced yield with high larval stocking-density in flow-through system.

Feeding experiments were carried out in 15-liter glass aquaria with 10 liters of water containing 1000 larvae aged 1.5 days post-hatching (before mouth opening) in three replicates. It was found that the feeding scheme of larval giant gourami aged 5-17 days (TL 8.36-13.40 mm) consumed Moina. The larvae aged 14-17 days (TL 12.40-13.40 mm) consumed both Moina and artificial pellet. Larvae aged more than 18-days (TL 13.60 mm) consumed only artificial pellet. Daily food uptake by the larvae and juvenile were determined in a 15-liter aquaria (water volume 10 liters) containing 500 larvae. The larvae were fed with Moina at density of 10 ind/ml. Aquaria without larvae were also set for a control of natural fluctuation in food density. The amount of food intake was calculated based on changes of food density in the aquarium with and without fish larvae. It was found the average uptake of Moina in digestive tract per day of larvae aged 5, 8, 11, 14 and 17 days old were 38, 52, 182, 205 and 266 individual/larva, respectively at density of 1.27, 1.73, 6.07, 6.83, and 8.87 individual/ml, respectively.

The aim of this work was to investigate the effects of glyphosate on the antioxidant system, as well as the neurotoxic effects on the larvae of Rhamdia quelen . A completely randomized design was implemented with the eggs of silver catfish distributed in 48 containers with 300 mL of water, which were subdivided randomly into two groups: control and treated with 6.5 mg L of glyphosate. These groups were evaluated at four time points (12 h, 24 h, 48 h, and 72 h), each with six replications. The survival rate of eggs/larvae (%) was evaluated, and samples were collected for antioxidant system analysis (catalase – CAT, glutathione transferase – GST, glutathione reductase – GR, and lipoperoxidation – LPO), and neurotoxic evaluation (cholinesterase – ChE). Throughout the 72 h of experimentation, there was a higher survival rate among the animals treated with glyphosate. The highest value of integrated biomarkers response (IBR = 1.26) was at 12 h, presenting induction of the cholinesterase (ChE) enzyme and GR. At 24 h, the value of IBR was −2.56, with inhibition of ChE and induction of GR. At 48 h, the value was −0.76, with induction of LPO. The lowest value of IBR was at 72 h (−4.65), with induction of GST and inhibition of all other biomarkers. Finally, it was possible to detect an acute effect of glyphosate throughout the early development of R. quelen , with a decrease in the antioxidant system control and neurotoxic effects. [ABSTRACT FROM AUTHOR]

Feeding copepods during early larval culture stages of marine fish has proven to be advantageous for growth and survival of marine finfish larvae. However, commercial availability of most copepods is limited; thus, there is an impetus to evaluate promising copepod species to meet the diverse dietary demands of various marine fish. The marine cyclopoid copepod, Oithona colcarva, was isolated out of zooplankton samples taken from waters within Tampa Bay, Florida. Once isolated, trials were conducted to determine the appropriate culture parameters for producing nauplii to feed marine fish larvae. The effects of temperature (22°C, 26°C and 30°C), salinity (15, 20, 25, 30 and 35 g L−1), stocking density (0.5, 1.0, 2.0, 4.0 and 8.0 individuals mL−1) and diet (Nanno 3600 microalgae paste, Colurella adriatica, Rhodomonas lens, Tisochrysis lutea, Chaetoceros gracilis and/or Tetraselmis chuii) on nauplii production during a single life cycle of reproducing individuals were examined. Results of those trials indicated that a culture temperature of 30°C and a salinity of 30 g L−1 were advantageous for maximum nauplii production. Furthermore, a diet containing a 1:1:1 mixture of T. lutea, C. gracilis and T. chuii and a stocking density of at least 8 individuals mL−1 were identified as beneficial. The results of these trials, the potential for large-scale culture and observations on the performance of marine fish larvae fed Oithona colcarva nauplii are discussed. [ABSTRACT FROM AUTHOR]

We investigated the effects of body size on the reproductive potential of the males of the Japanese spiny lobster Panulirus japonicus (von Siebold, 1824) under laboratory conditions to develop broodstock management techniques. The males were divided into three groups based on body size, each with three individuals: large (~90 mm carapace length (CL)), medium (~70 mm CL), and small (~60 mm CL). To evaluate the male reproductive potential, male lobsters were individually stocked in compartments in the tanks, and ten females with similar body size (~54-60 mm CL) were assigned to each male. Oviposition, egg fertilization rate, and clutch size were examined for females. Male body size affected the rates of oviposition and egg fertilization of the partners, resulting in lower reproductive success in the small-size male group. Female body size was associated with the clutch size, whereas male body size did not affect it. The egg fertilization rate, which was mediated by the male reproductive trait, affected the clutch size; low fertility reduced the clutch size. Our mating experiments highlighted the size-dependent reproductive potential of P. japonicus males, and we recommend that small males should not be used as broodstock in larviculture of this lobster. [ABSTRACT FROM AUTHOR]

This study compared the growth of sea urchin Paracentrotus lividus larvae cultured using two different rearing methods: a variable method based on a variable amount of feed (microalgae) and seawater exchange (30% or 50%) established according to the phytoplankton concentration in the larval cultures and a fixed method characterized by a fixed amount of feed and seawater exchange. Three microalgae diets, Isochrysis sp. (Tahitian strain, T-Iso), Chaetoceros gracilis and a 50:50 mixed diet, were tested with both rearing methods. Larval development and survival were assessed at the 6-arm pluteus stage (P6), competence (Cp) and metamorphosis (Mt). Data showed that the variable method reduced the requirements for phytoplankton and seawater exchange. Indeed, through the optimization of feed rations, it was possible to reduce the production of debris and settled phytoplankton, minimizing the need for water exchanges. Higher larval survival resulted at Cp and Mt stages for those reared with the variable method as opposed to the fixed one. Survival and development were also influenced by the tested dietary treatments: at Mt stage, the mixed diet resulted in a higher larval survival (63.3 ± 8.9%) than T-Iso (19.7 ± 12.1%) and C. gracilis (23.4 ± 15.1%) ( P < 0.05). These results suggest that the use of the variable method improves the larval survival and development and also it reduces resource consumption (phytoplankton, seawater use and work effort), which in turn could potentially improve the hatchery production of P. lividus. [ABSTRACT FROM AUTHOR]

Copyright of Revista de Biologia Marina y Oceanografía (RBMO) is the property of Universidad de Valparaiso, Facultad de Ciencias del Mar and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

We examined short-term, inter- and intra-individual variability in rates of growth and food consumption in fish early life stages to gain a mechanistic understanding of why larvae in the same environments often grow at vastly different rates. We made parallel measurements of growth rate in standard length ( GRSL) and food consumption rate (C), and provide estimates of weight growth rate ( GRDW) and gross growth efficiency ( GGE = 100* GRDW/C) of individually reared larvae of pikeperch, Sander lucioperca L., fed Artemia nauplii at 20°C and a salinity of 2.0 g L−1. Within two trials, GRSL, C and GGE were obtained for 108 larvae over a maximum period of 28 days. Mean (± SD) initial size, GRSL, C and GGE were 19.49 (9.19) mm, 0.68 (0.21) mm day−1, 0.85 (0.44) mg day−1 and 36.5 (10.2)% respectively. The vast majority (91%) of the variability in growth was explained by differences in food consumption. When isolated from conspecifics for 28 days, relatively small larvae grew faster than relatively large ones, partially mitigating initial differences in size-at-age. [ABSTRACT FROM AUTHOR]

This study describes the effects of feeding taurine-supplemented Artemia on the growth, survival, whole body taurine content and jaw malformation rate of larval yellowtail kingfish Seriola lalandi. Larvae were fed rotifers containing no supplemental taurine from 3 to 15 day post hatch (dph) and Artemia co-enriched with taurine from 12 to 22 dph. Artemia were supplemented at concentrations of either 0, 0.8, 1.6, 2.4, 3.2 or 4.0 g of taurine L−1 during the 18 h HUFA enrichment process. Taurine content in the Artemia increased from 0.76 ± 0.04% DW in those without supplementation to 3.95 ± 0.17% DW in those supplemented at 4.0 g L−1. Survival rates of larval yellowtail kingfish were significantly lower in all taurine-supplemented treatments compared to the unsupplemented control. Growth was significantly improved in those larvae fed taurine-supplemented Artemia; however, we cannot attribute this improvement solely to taurine, as improved growth may have been a function of the reduced survival, and therefore increased prey availability, in these treatments. The whole body taurine content of larvae fed unsupplemented Artemia was significantly lower (1.85 ± 0.03% DW) than those fed supplemented Artemia, which did not differ from each other (pooled average 2.48 ± 0.03% DW), suggesting either a functional excretion mechanism is in place or that this represents the saturation value for larvae of this age. Jaw malformation rates were not affected by Artemia taurine content. The results of this research suggest yellowtail kingfish larvae may have a lower requirement and/or a reduced tolerance to excess dietary taurine than juveniles. [ABSTRACT FROM AUTHOR]

The phyllosoma larvae of the slipper lobster Eduarctus martensii (Pfeffer, 1881) were first time successfully hatched in the laboratory and reared to Stage VI. It took 24 days for newly hatched larvae to reach Stage VI. We also confirmed the identities of wild-caught phyllosomas of this species by DNA barcoding of the mitochondrial 16S rRNA gene (sequence similarities 98.8%-99.8%), including two late-stage individuals that developed into a nisto and an early juvenile. The diagnoses for all nine phyllosoma stages, the nisto, and the early juvenile are provided, with the number of rows of aesthetascs on the antennule appearing to be useful in assigning the developmental stage of the phyllosomas in E. martensii. The present confirmation of the identities of the phyllosomas of E. martensii reveals that previous reports on the developmental stages of this species contain inaccurate information and some even refer to different taxa. [ABSTRACT FROM AUTHOR]

This study was conducted to evaluate the effect of tank colour on growth and survival of taimen Hucho taimen larvae. Larvae (initial weight 0.11 ± 0.01 g, 21 days after hatching) were cultured in the water flow-through system. Fifteen aquaria (200 L per aquarium) were randomly allocated into triplicate groups of 500 larvae. The outsides of the tanks were covered in red, blue, yellow, white, or black sheeting. Larvae were fed eight times a day by hand to apparent satiation. The experiment was conducted for 56 days. The results showed that the specific growth rate was significantly affected by tank colour, which was higher in the yellow tank than that of the tank (black or red) ( P < 0.05). The tank colour did not significantly affect survival, condition factor, and feed conversion ratio among all the treatments ( P > 0.05). The highest feed intake was observed in fish reared in the yellow tank, followed by that of the white, blue, or black tank, and the lowest was in fish in the red tank. In conclusion, the light-coloured tank (yellow or white) was optimum for rearing taimen larvae based on the growth performance. [ABSTRACT FROM AUTHOR]

We studied the effect of dietary microalgae on the fecundity, population development, and fatty acid profile [with focus on the essential fatty acids docosahexaenoic acid (DHA; 22:6ω3) and eicosapentaenoic acid (EPA; 20:5ω3)] of the calanoid copepod Pseudodiaptomus hessei , a potential live food for finfish larvae in aquaculture. Two mono-algal diets, the Tahitian strain of Isochrysis galbana and Rhodomonas salina , and a 50:50 binary diet of the two were fed to copepods. Wild caught copepods were used as a baseline reference point. Copepods fed I. galbana and the 50:50 binary diet had high DHA:EPA ratios and DHA content relative to those fed R. salina . The EPA content of the copepods was similar for all three diets. Copepods fed R. salina had the highest fecundity relative to those fed I. galbana and the 50:50 binary diet. The largest population was obtained when the copepods were fed I. galbana , which differed from those fed R. salina and the 50:50 binary diet. The results of this study showed that the fatty acid composition of P. hessei can be altered by changing its dietary microalgae, and that the copepod can accumulate fatty acids from its diet, especially DHA and EPA. Diet also affected fecundity and population development of P. hessei , so this species represents a potential live food candidate for marine finfish larvae as its nutritional composition and productivity can be manipulated to suit the needs of marine finfish larvae. [ABSTRACT FROM AUTHOR]

Lake sturgeon (Acipenser fulvescens) are critically endangered across their native Canadian range and thus conservation aquaculture is practiced to restock historically decimated wild populations. However, as in many aquaculture settings, episodes of mass mortality occur throughout larval development and are often linked to periods of dietary transition. Thyroid hormones play a critical role in larval development and metamorphosis, including the transition from endogenous to exogenous feeding, and thus have been utilized in aquaculture to promote hatch rate, growth, and survivability in multiple fish species. The objective of the present study was to determine whether exogenous application of the biologically active thyroid hormone, triiodothyronine (T 3), could improve lake sturgeon growth and survival during early ontogeny in two distinct rearing environments; tumbling jars representing hatchery conditions or egg mats representing more natural conditions. Waterborne application of 3 ppm T 3 during fertilization improved growth and survival of lake sturgeon during the first month of life, with greater effects observed in the egg mat environment. Concomitant increases in mRNA abundance of genes involved in appetite regulation (e.g., neuropeptide Y and orexin) and somatic growth (e.g., insulin-like growth factor 1) support accelerated growth of T 3 exposed fish through multiple neuroendocrine axes. Following the transition to an exogenous diet, transcript abundance was significantly reduced in the T 3 group when compared to controls, perhaps indicating negative feedback regulation. T 3 application also caused transient reductions in whole body cortisol content and reduced transcript abundance of genes related to the stress axis later in development; however, no apparent negative consequences were observed as a result. Finally, oral dosing of 3 ppm T 3 during an exogenous dietary transition in juvenile lake sturgeon at ∼1.5 months post fertilization significantly increased sturgeon mass, but not survival, indicating that exogenous T 3 can contribute to the success of young-of-the-year sturgeon during dietary transitions at multiple life stages. Therefore, these data demonstrate that elevated survivorship and growth associated with exogenous T 3 application during fertilization are associated with upregulation of hypothalamus-pituitary-thyroid/interrenal, gut-brain, and somatotropic axes. Overall, exogenous T 3 application represents a cost-effective way to positively influence lake sturgeon growth and survival at key dietary transitions during early development. Further, this study adds to a growing body of literature demonstrating beneficial effects of thyroid hormone treatment in fish aquaculture. • Application of 3 ppm T 3 at fertilization improves lake sturgeon survival. • T 3 survivorship increases when reared on egg mats compared to tumbling jars. • T 3 increases growth and appetite related transcripts prior to exogenous feeding. • T 3 suppresses the stress axis with no negative consequences in measured endpoints. [ABSTRACT FROM AUTHOR]

Largemouth bass (LMB), Micropterus salmoides , is the most popular sportfish in the United States, with an expanding global food market. Farmers traditionally raise LMB in earthen ponds that are often plagued with high mortality during the early life history stages. Replacing initial pond stages with intensive indoor culture would streamline production and minimize losses. Our objectives were to (i) identify an optimal thermal regimen for rearing LMB in an indoor recirculation aquaculture system (RAS), (ii) assess the performance of Florida vs. Northern LMB for RAS culture, and (iii) elucidate thermally induced phenotypic changes and inter-linked expression of targeted genes involved in early development. Using RAS, Florida and Northern LMB were raised at 21 °C, 24 °C, and 27 °C. Fish were randomly sampled at 2 to 28 days post-hatch (dph) for total length (TL), body area (BA), myotome height (MH), jaw length (JL), eye diameter (ED), oil droplet area (ODA), and yolk area (YA). Condition index, yolk utilization efficiency (YUE), and yolk utilization rate (YUR) were calculated. Wet weight and survival were taken at 29 dph with expression of targeted genes [growth hormone (gh), insulin-like growth factor 1 (igf1), heat shock protein 70 (hsp70)] determined at 8 and 28 dph. There was a temperature effect on all morphometric traits, where both subspecies increased in size over the temperature gradient, with the largest morphometric traits (TL, BA, MH, JL, ED) detected at 27 °C. Larvae had smaller remaining ODA and YA reserves as temperatures increased. Larvae reared at 27 °C utilized their yolk at faster rates and were most efficient at converting yolk reserves to body size. Northern LMB had higher YUE than Florida LMB and were typically larger and heavier at 29 dph. LMB reared at 21 °C had higher survival than those at 24 or 27 °C, while Northern LMB had higher survival than Florida LMB. For Florida LMB, no differences in gh and igf 1 were detected across temperatures at 8 dph. However, at 28 dph, these genes were upregulated at 27 °C, while expression of hsp70 was downregulated at 24 and 27 °C. Northern LMB showed similar expression patterns, with no significant differences detected. In conclusion, the present study suggests that 1) rearing LMB at 27 °C may improve growth performance during early ontogeny, and 2) Northern LMB may be selected for faster growth when reared in an indoor RAS. • Largemouth bass is the most popular sportfish in US with expanding global food market. • Replacing pond stages with intensive indoor culture would streamline production. • Rearing at 27 °C improves growth performance during early ontogeny. • Northern LMB can be selected for faster growth when reared in an indoor RAS. [ABSTRACT FROM AUTHOR]

The primary aim of this study was to comprehensively evaluate the welfare of Nile tilapia (Oreochromis niloticus) throughout their entire life cycle within aquaculture, spanning from reproduction to slaughter. The methodology was structured to identify welfare indicators closely aligned with the principles of animal freedoms defined by the Farm Animal Council, encompassing environmental, health, nutritional, behavioral, and psychological freedom. Notably, psychological freedom was inherently considered within the behavioral and physical analyses of the animals. To accomplish this, an integrative systematic literature review was conducted to define precise indicators and their corresponding reference values for each stage of tilapia cultivation. These reference values were subsequently categorized using a scoring system that assessed the deviation of each indicator from established ideal (score 1), tolerable (score 2), and critical (score 3) ranges for the welfare of the target species. Subsequently, a laboratory experiment was executed to validate the pre-selected health indicators, specifically tailored for the early life stages of tilapia. This test facilitated an assessment of the applicability of these indicators under operational conditions. Building on the insights gained from this experimentation, partial welfare indices (PWIs) were computed for each assessed freedom, culminating in the derivation of a general welfare index (GWI). Mathematical equations were employed to calculate these indices, offering a quantitative and standardized measure of welfare. This approach equips tilapia farmers and processors with the tools necessary for the continuous monitoring and enhancement of their production systems and stimulate the adoption of more sustainable and ethical practices within the tilapia farming., Competing Interests: AP was employed by Wai Ora Aquaculture and Environmental Technology Ltd. MQ was employed by FAI Farms from Brazil. The remaining authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest., (Copyright © 2023 Pedrazzani, Cozer, Quintiliano, Tavares, Biernaski and Ostrensky.)

The effects of the replacement of bread yeast by soybean meal in diets for Rhamdia quelen larvae on growth, survival, and intestinal morphology were analysed. Larvae were fed for 20 days with five diets: a control diet formulated with 57% of bread yeast, and other four diets in which soybean meal at concentrations of 14.25, 28.5, 42.75 and 57% was added to obtain 25, 50, 75 and 100% of bread yeast replacement. Growth and survival parameters were negatively affected by dietary soybean meal inclusion. Larvae fed control diet showed significantly higher mean weight, specific growth rate, final biomass, and survival rate than larvae from other treatments. Enterocyte height and fold width of the posterior intestine showed highest values in the control group, and an inverse linear relationship with the level of dietary soybean meal inclusion was observed, however, in the anterior intestine the morphology parameters were not affected by the diet. These results indicate that inclusion of soybean meal in diets for R. quelen larvae negatively affects growth and survival, as well as the capacity for digestion and absorption of nutrients, mainly in the posterior intestine.Neste estudo, foi analisado o efeito da substituição de levedura de pão por farelo de soja em dietas para larvas de Rhamdia quelen no crescimento, sobrevivência e morfologia intestinal. As larvas foram alimentadas durante 20 dias com cinco dietas experimentais: uma dieta controle formulada com 57% de levedura de pão e quatro dietas em que o farelo de soja foi adicionado em 14,25, 28,5, 42,75 e 57% para obter 25, 50, 75 e 100% de substituição de levedura de pão. As variáveis de crescimento e sobrevivência foram negativamente afetadas pela inclusão da soja na dieta. As larvas alimentadas com a dieta controle apresentaram maior peso médio, taxa de crescimento específico, biomassa final e sobrevivência, diferindo significativamente dos demais tratamentos. A altura dos enterócitos e a largura das pregas no intestino posterior apresentaram valores mais elevados no grupo controle, enquanto nos demais tratamentos mostraram uma relação linear inversa com o nível de inclusão de farelo de soja na dieta. No entanto, no intestino anterior, os parâmetros morfológicos não foram afetados pela dieta. Esses resultados indicam que a inclusão de farelo de soja em dietas para larvas de R. quelen afeta negativamente o crescimento e sobrevivência, bem como a capacidade de digestão e absorção de nutrientes, principalmente no intestino posterior.

In this study, the Vibrio probioticus was isolated from the gut of female Portunus pleagicus, identified through 16S rDNA gene sequencing, and was evaluated for its probiotic features. The probiont was tested in co-culture assay at various concentrations against three target shellfish pathogens including V. harveyi, V. parahaemolyticus and Pseudoalteromonas piscicida. In a co-culture assay it was apparent that the V. probioticus had shown to outcompete the growth of tested pathogenic bacteria due to its antibacteriocin properties. Different ratios produced different effect on tested pathogens, however, the highest ratio (pathogen:probiont) was more effective in suppressing the pathogen. A maximum inhibition growth was recorded for V. harveyi and P. piscicida. The probionts could further be tested in vivo culture environment to understand the effectiveness in microbial control of P. pelagicus larviculture and other aquaculture species.

The objective of this study was to evaluate the effect of different levels of diet crude protein on the performance and stress resistance rate (Re) of Oreochromis niloticus larvae and fingerlings. In the first experiment, 5, 15 and 25 day-old animals were submitted to 1, 5, 7, 10, 15, 20, 30 and 40 minutes of air exposure on a sieve. In the second experiment, tilapia larvae were fed with 32, 40 and 55% crude protein (CP) diets. Animals after 15 and 30 days of feeding (21 and 36 days of life, respectively) were submitted to the air exposure test for 7 and 10 minutes. Re was estimated based on survival 24 hours after the tests. In the first experiment, it was observed that 5-day-old animals were more resistant than animals with 10 and 20 days of feeding (15 and 25 days of life, respectively), when Re starts to decrease for longer than 7 minutes. In the second experiment, the different diets affected survival, performance and Re, and, in general, the worst results observed were the ones for the animals which received the 55% CP diet. The air exposure tests were efficient to evaluate the effect of diet on the resistance rate of Nile tilapia.

Foram comparados os efeitos de diferentes dietas e da transição alimentar sobre o desempenho zootécnico e a morfologia do trato digestório de larvas de pacu alimentadas com duas dietas comerciais e uma dieta experimental microencapsulada produzida por gelificação interna. Larvas com quatro dias de vida receberam os seguintes protocolos alimentares: somente náuplios de artêmia em quantidades crescentes (controle positivo); larvas mantidas em jejum (controle negativo); três tipos de alimento formulado durante todo o experimento (dieta experimental microencapsulada, dieta comercial NRD1.2/2.0, Inve, USA, e dieta Poli-Peixe 450F, PoliNutri, Brasil); e três protocolos de transição alimentar com náuplios de artêmia durante os seis primeiros dias, seis dias de coalimentação, e somente as respectivas dietas formuladas após esse período. O experimento foi conduzido por 23 dias em delineamento inteiramente casualizado, com avaliações periódicas do crescimento e do sistema digestório. A taxa de sobrevivência foi determinada ao final do experimento. Os melhores desempenhos de crescimento e sobrevivência, assim como mais acelerada organogênese do sistema digestório, foram verificados entre os animais que receberam alimento vivo. As larvas que passaram pela transição alimentar apresentaram médias intermediárias de crescimento e sobrevivência e não diferiram entre si. Entre os grupos que receberam apenas dieta inerte, somente naquele alimentado com a dieta nacional houve sobrevivência até o final do experimento. Nenhuma das dietas formuladas é adequada para uso como alimento exclusivo para larvas de pacu. Na fase de transição alimentar, a dieta experimental microencapsulada proporciona resultados de sobrevivência e crescimento semelhantes aos obtidos com dietas comerciais.The effects of different diets and dietary transition on the performance and morphology of the digestive tract of pacu larvae fed two commercial formulated diets and an experimental microencapsulated diet produced by internal gelation were evaluated. Four-day old pacu larvae received the following treatments: only artemia nauplii in increasing amount during the experiment (positive control); larvae maintained at fasting (negative control); three types of formulated diets throughout the experiment (experimental microencapsulated diet, commercial diet NRD1.2/2.0, Inve, USA, and diet Poli-Peixe 450F, PoliNutri, Brazil); and three weaning protocols in which artemia nauplii were given from the 1st to 6th days, six days of co-feeding (artemia nauplii + the respective formulated diet), and only respective diets formulated after this period. The experiment was conducted for 23 days in a completely randomized design, with periodical evaluations of growth and digestive system. Survival rate was determined at the end of the experiment.The best performances of growth and survival, as well as the organogenesis of the digestive tract, were verified for the animals which received live feed. The larvae at weaning treatments induced intermediate growth and survival, which did not differ statistically between them. Considering the treatments that received only formulated diets as first feed, the PoliNutri diet was the unique that showed alive larvae at the end of experiment. None of the formulated diets are adequate as initial exogenous food for pacu larvae. During the weaning, the microencapsulated experimental diet provides growth and survival performances similar to those obtained with the commercial diets.

The sexual maturity of female snake head fish, Channa striatus was studied by determining fecundity and gonadosomaticindex (GSI). It was found that the size at sexual maturity of female snake head fish was 26.45±3.07 cm (mean ± SD,n=10) in total length and 167.4±48.09 g in body weight. The eggs were floating and rounded. The fertilized eggs had a diameterof 588±20.43 m. The fecundity was 10,279.1±2,527.9 ova/fish and gonadosomatic index (GSI) was 5.07±1.04 %.Newly hatched larvae of snake head fish were produced by induced spawning using chemical injection (Suprefactand Motilium). The sexually mature fishes were cultured in a fiber-glass tank (water volume 300 liters) with the ratio of maleand female brooders 1:1. The fertilization rate, hatching out and hatching rate experiments were carried out using 3 15-literglass aquaria (water volume 10 liters) each containing 1,000 eggs. It was found that the average fertilization rate was 76.50%,hatching out occurred of 28 hr 40 min and average hatching rate was 60.26 % at a water temperature of 26.5-29.0°C. Samplingof the newly-hatched larvae was done at 2-hour intervals, when 20 of them were randomly taken and preserved in 10%buffered formalin for later determination of yolk absorption time. Observation using a microscope revealed that newlyhatched larvae were 3.18±0.11 mm in total length and had yolk sacs of 1,279.71±196.10 m3 in volume. The yolk sacs werecompletely absorbed within 80 hr after hatching at a water temperature of 26.5-29.0°C. Up until full mouth development (startof feeding), 2-hourly samplings of twenty newly hatched larvae were taken from an aquarium for observation of the size ofmouth opening. All the larvae had open mouths about 52 hr after hatching (5.48±0.16 mm TL), and measured 324.30±144.60m in mouth opening.The feeding experiments were carried out using a 15-liter glass aquarium (water volume 10 liters) containing 1,000larvae aged 1.5 days post-hatching (just before the mouth opened). They were fed with Moina at a density of 10 individual/ml. Twenty larvae were collected at random from the aquarium at 2-hourly intervals, preserved in 10 % buffered formalin, andthen dissected to determine the presence of Moina in the digestive tract. The digestive tracts were fixed at 62 hr of hatchingat water temperatures of 28.0-30.5°C, and measured 334.87±149.78 m in mouth opening. The average number of Moina inthe digestive tract at the start of feeding was 0.56 individual/larva.

Feeding scheme experiments were done in a 15-liter glass aquarium (water volume 10 liters) containing 500 of two-dayold larvae (stage at first feeding). It was found that larval snake head fish aged 3-11 days (average total length 6.08-10.86 mm)consumed Moina. Larvae aged 12-15 days (average total length 10.79-14.61 mm) consumed both Moina and commercialpellet (40 % crude protein). Larvae aged more than 16 days consumed only commercial pellet.Determining the daily food uptake by the larvae and juveniles was done in a 15-liter glass aquarium (water volume 10liters) containing 1,000 larvae. The larvae consumed Moina ,provide of a density of Moina 10 individual/ml. The amount offood intake was calculated based on changes of food density in the aquarium with and without fish larvae at 2-hour intervals.It was found that larvae aged 3-15 days consumed Moina. The average uptake of Moina in digestive tract per day of larvaeage 3, 6, 9, 12 and 15 days old was 28.7, 115.70, 162.27, 195.30 and 227.30 individual/larva, respectively at water temperaturesranging between 25 and 28°C.A starvation experiment was carried out using a 15-liter glass aquarium (water volume 10 liters) with three replications.Two hundred newly hatched larvae were kept without feeding. Larvae started to die at 216 hr and totally died within 326 hrafter hatching at water temperature ranging between 28.0 and 30.5°C.

El objetivo del estudio fue evaluar el efecto de la densidad de presas en la larvicultura de dorada Brycon sinuensis, para lo cual fueron ofrecidas, durante 24 horas, cuatro proporciones presa-predador 0:1 (T1), 1:1 (T2), 2:1 (T3) y 4:1 (T4) al inicio de la alimentación exógena. Como presa fueron utilizadas larvas recién eclosionadas de bocachico Prochilodus magdalenae, suministradas por una sola vez. Las larvas de dorada se pesaron y se midieron al inicio y al final del experimento para estimar ganancia en peso (Gp), ganancia en longitud (Gl) y tasa de crecimiento específico (G); también se calculó la sobrevivencia (S), resistencia al estrés (Re), mortalidad natural (Mn) y por canibalismo (Mc). Los mayores valores de Gp (3.9 ± 0.4 mg) y G se registraron en T4 (5.8 ± 0.4%/h), presentando diferencia significativa con los demás tratamientos (p0.05); pero si con relación a T1. Cuando se alimentó con dos (T3=84.2%) y cuatro larvas forrajeras por cada larva de dorada (T4=86.7%) se observaron las mayores sobrevivencias; mientras que la menor se obtuvo cuando no se suministraron larvas forrajeras (T1=51.8%); encontrándose en ese tratamiento la mayor mortalidad por canibalismo (46.3%). Asimismo, las menores mortalidades por canibalismo se presentaron cuando se ofrecieron entre dos (T3=12.7%) y cuatro larvas forrajeras por cada larva de dorada (T4=12.0%). La mortalidad natural fue baja y osciló entre 1.3% (T4) y 3.2% (T3) sin observarse diferencia significativa (p>0.05). Los valores de la prueba de Re oscilaron entre 86.7 ± 10.3% (T1) y 95.0 ± 5.5% (T3) sin observarse diferencia significativa (p>0.05). Estos resultados indican que suministrar entre dos y cuatro larvas forrajeras como primera alimentación en dorada reduce el canibalismo y ofrece mejores resultados de sobrevivencia y crecimiento durante la larvicultura.O objetivo do estudo foi avaliar o efeito da densidade de presas na larvicultura de Dorada Brycon sinuensis, para o qual foram fornecidas, durante 24 horas, quatro diferente proporção presa-predador 0:1 (T1), 1:1 (T2), 2:1 (T3) e 4:1 (T4) ao inicio da alimentação exógena. Como presa foram utilizadas larvas recém eclodidas de Bocachico Prochilodus magdalenae, as cuais foram fornecidas por uma única vez. As larvas de Dorada foram pesadas e medidas ao inicio e final do experimento para calcular ganho de peso (Gp), ganho de comprimento (Gl) e taxa de crescimento específico (G); também foi calculada a supervivência (S), resistência ao estresse (Re), mortalidade natural (Mn) y mortalidade pelo canibalismo (Mc). Os maiores valores de Gp (3.9 ± 0.4 mg) e G (5.8 ± 0.4%/h) foram registradas no T4, apresentando diferença com os demais tratamentos (p0.05); mas sim com relação a T1. Quando foi alimentado com duas (T3 = 84.2%) e quatro larvas forrageiras por cada larva de dorada (T4 = 86.7%) foram observadas as maiores supervivências; ainda que a menor obteve se quando não foram fornecidas larvas forrageiras (T1 = 51.8%); foi encontrado nesse tratamento a maior mortalidade pelo canibalismo (46.3%). Assim mesmo, as menores mortalidades por canibalismo apresentaram-se quando foram fornecidas entre duas (T3 = 12.7%) e quatro larvas forrageiras por cada larva de Dorada (T4 = 12.0%). A mortalidade natural foi baixa e oscilou entre 1.3% (T4) e 3.2% (T3) sem diferença significativa (p>0.05). Os valores do teste de Re estiveram entre 86.7 ± 10.3% (T1) e 95.0 ± 5.5% (T3) sem diferença significativa (p>0.05). Estes resultados indicam que fornecer entre duas e quatro larvas forrajeiras como primeira alimentação em larvas de Dorada diminui o canibalismo e oferece melhores resultados de supervivência e crescimento durante a larvicultura.This study evaluated several predator-prey ratios on Dorada (Brycon sinuensis) larviculture. The onset of exogenous feeding using four predator-prey ratios 0:1 (T1), 1:1 (T2), 2:1 (T3) and 4:1 (T4) was studied. The preys used were newly hatched Bocachico (Prochilodus magdalenae) larvae, which were fed just once. The Dorada larvae were weighed and measured at the beginning and the end of the experiment. The variables measured were weight gain (Wg), length gain (Gl), specific growth rate (G), survival (S), stress resistance (Rs), natural mortality (Nm) and cannibalism mortality (Mc). The T4 had the highest Wg (3.9 ± 0.4 mg) and G (5.8 ± 0.4%/h). Survivability was increased when feeding two (T3 = 84.2%) and four forage larvae for each Dorada larvae (T4 = 86.7%). The lowest survivability was observed when no forage larvae were fed (T1 = 51.8%), coinciding with the greatest mortality from cannibalism (46.3%). The lowest mortality from cannibalism occurred when two (T3 = 12.7%) to four forage larvae per Dorada larvae (T4 = 12.0%) were offered. Natural mortality was low, ranging between 1.3% (T4) and 3.2% (T3) (p> 0.05). The test values of Rs ranged from 86.7 ± 10.3% (T1) and 95.0 ± 5.5% (T3) (p>0.05). These results indicate that offering between two and four forage larvae as first feeding to Dorada larvae reduces cannibalism and offers the best results for survival and growth during larviculture.

This study aimed to evaluate the influence of photoperiod on juvenile suruvi (Steindachneridion scriptum) in six photoperiods: 24L-0D (L= Light; D= Dark), 18L-6D, 14L-10D, 10L-14D, 6L-18D and 0L-24D. Juveniles measuring 176.8 ± 13.2mm and weighing 60.2 ± 16.0g were distributed in eighteen 150-L aquariums, stocked with 8 juveniles per aquarium. At the end of the study, treatments 24L-0D (105.7 ± 5.8g and 845.9 ±46g) and 0L-24D (93.3 ± 4.9g and 746.4 ± 39.5g) were different (P0.05) in all the treatments. The results showed that suruvi (Steindachneridion scriptum) reached better weight and biomass in extended light periods.O objetivo do presente estudo foi avaliar a influência do fotoperíodo no cultivo de juvenis de suruvi Steindachneridion scriptum, nos seguintes fotoperíodos: 24L-0E (L=Luz; E= Escuro), 18L-6E, 14L-10E, 10L-14E, 6L-18E e 0L-24E. Juvenis com comprimento e peso médio de 176,8± 13,2mm e 60,2± 16,0g, respectivamente, foram distribuídos em 18 tanques de 150L, estocados na densidade de oito juvenis por tanques. Decorridos 90 dias de cultivo foram encontradas diferenças (P0,05) na sobrevivência (100,0 ± 0,0%) e no comprimento total (212,5 ± 2,5mm). Nas condições apresentadas os resultados nos permitem concluir que o suruvi, Steindachneridion scriptum, atingiu melhor peso e biomassa em cultivos que apresentam períodos com iluminação.

Aquaculture of marine ornamental fish is an important tool that may help to provide sustainable alternatives to wild caught individuals. Many challenges are associated with marine ornamental aquaculture, especially during the larviculture process. Newly hatched marine larvae are often underdeveloped at hatch and require specific nutritional and environmental parameters for successful morphogenesis and ultimate metamorphosis into the juvenile stage. The Pacific blue tang (Paracanthurus hepatus) is a promising candidate for ornamental aquaculture due to its popularity in the aquarium trade and prior captive breeding success. However, improvements in culture methodologies, especially environmental and nutritional factors, is critical to viable commercial production. Seven experiments were conducted to determine appropriate green water culture conditions, photoperiod, and feeding protocols that best promoted survival, growth, and ingestion rate in early-stage P. hepatus larvae. Larval survival and feeding incidence were significantly increased when live microalgae was added to the culture system. The survival and feeding incidence of 3 days post hatch (DPH) P. hepatus larvae was greatest when the algae species Tisochrysis lutea was incorporated at a density of 300,000 cells/mL. The feeding incidence of 3 DPH larvae was not affected by prey type or prey density. When free amino acid feeding stimulants were added to the culture water, neither larval survival nor feeding incidence were improved. Lastly, the photoperiod that best promoted larval growth and survival was 16-h light: 8-h dark. Together, these results provide for improved larval survival in aquaculture and help move P. hepatus towards viable commercial production. • Tisochrysis lutea at a density of 300,000 cells/mL best promoted larval survival and feeding incidence. • Prey density did not significantly influence larval feeding incidence at first feeding. • Larvae showed no preference between Oithona colcarva and Parvocalanus crassirostris nauplii. • Certain feeding stimulants resulted in lower larval survival and had no effect on feeding incidence. • Larval survival and growth was greatest with a photoperiod of 16 light: 8 dark. [ABSTRACT FROM AUTHOR]

This study aimed to evaluate the effects of four potential microbial strains, consisting of Candida parapsilosis , Pseudoalteromonas flavipulchra , Lactobacillus sakei , and Bacillus natto , on the suppression of Vibrio and the increase of population growth and enzyme activity in the copepod Tigriopus japonicus. Five treatments were set up, including four experimental groups and a control, each with four replicates. For each strain a concentration 108CFU/mL−1 was applied. The results demonstrated that the use of L. sakei and B. natto, besides suppression of Vibrio , could increase the population growth and enzyme activity in copepods. The longevity of B. natto was recorded as the best in long-term inoculation in a way that after 8 days of copepod starvation, the count of B. natto after a significant decrease first, increased again. The findings showed that B. natto appears to be a promising bacterial strain for the copepod T. japonicus in the suppression of Vibrio and also in increasing the population growth, enzyme activity, and long-term inoculation potential. • Bacillus natto is an impressive strain that can stick in Copepods' digestive tract for long term, even if used for once. • Tigriopus japonicus base on its response in this study can be a potential live food for larviculture with enrichment possibility. • The use of C. parapsilosis , P. flavipulchra , L. sakei , and B. natto besides suppression of Vibrio showed a proper effect on population growth and enzyme activity. [ABSTRACT FROM AUTHOR]

Clownfish (Amphiprion ocellaris) are the most recognizable and popular marine aquarium fish and are a key commodity for marine ornamental fish producers. Although these fish have been raised in captivity for decades, producers are still experiencing issues regarding larval survival, reliance on live feeds, and post-larval deformities. To improve the culture process, the ontogeny of larval development and digestive capacity should be elucidated. The morphological development, digestive enzyme ontogeny, and digestive tract development of A. ocellaris was examined in a 16-day trial. Standard microplate assays were conducted to quantify the activity of trypsin, lipase, and acid protease enzymes from 24 h before hatching to 15 days post hatch (DPH). Histology was used to visualize morphological changes in the digestive tract throughout the larval period. At hatching, A. ocellaris has functional eyes, an open mouth, and a coiled, differentiated digestive tract. Trypsin and lipase activities were detectable before hatching and increased significantly later in the larval period. Gastric gland formation was observed at 6 DPH, with stomach functionality occurring between 7 and 9 DPH, indicated by gastric gland proliferation and an increase in acid protease activity. The results from this study may be used to inform weaning protocols to maximize larval growth and survival while minimizing the use of costly live feeds. • The ontogeny of the digestive tract of larval A. ocellaris was examined to gain insight into the timing of gut maturation. • Gastric gland functionality was found at 7 DPH, indicated by positive Periodic-Acid Schiff staining. • A. ocellaris larval begin to undergo metamorphosis at 9 DPH, with subsequent settlement occurring at 11 DPH. • The results from this study can be used to design and refine standardized rearing protocols for A. ocellaris. [ABSTRACT FROM AUTHOR]

Brazilian basslet Gramma brasiliensis is a fish highly appreciated by the marine ornamental industry. There is an increasing interest in the development of a breeding protocol for this species. However, descriptions of the reproductive biology, eggs and larval development are scarce. This study was the first to describe the spawning, eggs and larvae of G. brasiliensis in captivity, including mouth size information. Six spawning events produced egg masses with 27, 127, 600, 750, 850, and 950 eggs. Larger egg masses showed embryos with at least two different developmental stages. Eggs are spherical (∼1.0 mm diameter), held together by filaments entangling chorionic projections. Larvae with fewer than 12 hph (hours post-hatch) presented 3.55 mm standard-length, well developed eyes, fully absorbed yolk sac, an inflated swim bladder and mouth opened. Exogenous feeding on rotifers began within 12 hph. The average mouth width at first feeding was 0.38 mm. The first settled larva was noted by day 21. This information should help to determine appropriate diets and prey-shift time during the larviculture of the species.

The effect of food and photoperiod on dorado (Salminus brasiliensis) post-larvae growth and survival was investigated using the following treatments: LD (Light: Dark) 24:0 + Artemia nauplii (A), LD 24:0 + fish prey (F), LD 14:10 + A, LD 14:10 + F, LD 0:24 +A and LD 0:24 + F. Prochilodus lineatus larvae were used as fish prey. Higher survival rates were registered in fish prey treatments (PO efeito da alimentação e do fotoperíodo sobre o crescimento e a sobrevivência de pós-larvas de dourado (Salminus brasiliensis) foi investigado utilizando-se os seguintes tratamentos: LE (Luz: Escuro) 24:0 + náuplios de Artemia (A), LE 24:0 + larva forrageira (L), LE 14:10 + A, LE 14:10 + L, LE 0:24 +A e LE 0:24 + L. Larvas de Prochilodus lineatus foram utilizadas como larva forrageira. Taxas de sobrevivência mais elevadas foram registradas nos tratamentos que utilizaram larvas forrageiras (P

O objetivo deste trabalho foi avaliar o efeito da alimentação na resistência ao estresse e no crescimento de larvas das espécies de peixes neotropicais: Astronotus ocellatus (Oscar), Piaractus mesopotamicus (pacu) e Pseudoplatystoma coruscans (pintado). As larvas receberam diferentes tipos de alimentos (Artemia sp., larvas de Colossoma macropomum e dieta artificial Fry Feed Kyowa). Foram realizados testes de exposição ao ar e a taxa de sobrevivência, determinada 24 horas depois. A fim de avaliar o crescimento, medidas de peso foram realizadas em larvas dos diferentes tratamentos. Larvas de A. ocellatus alimentadas com náuplios de Artemia sp. apresentaram tendência de maior peso e resistência ao estresse, quando comparadas com o uso de dieta artificial. Larvas de P. mesopotamicus apresentaram melhores valores de peso e taxas de resistência ao estresse, quando alimentadas com Artemia sp. ou alimentação mista (Artemia sp. + dieta artificial). Em P. coruscans, o uso de larvas forrageiras resultou em indivíduos mais resistentes aos testes de exposição ao ar do que os que receberam apenas Artemia sp. Valores de peso, nos dois manejos alimentares, foram semelhantes entre si. O alimento vivo desempenha importante atuação no crescimento em peso e na melhora da resistência ao estresse das espécies estudadas.The objective of this work was to evaluate the effect of feeding on stress resistance and growth in larvae of neotropical fish of the species: Astronotus ocellatus, Piaractus mesopotamicus, and Pseudoplatystoma coruscans. Larvae received different types of food (Artemia sp., Colossoma macropomum larvae and artificial microdiet Fry Feed Kyowa). Resistance tests to air exposure were applied, and larvae survival was determined after 24 hours. To evaluate the growth, weight measures were performed during the different treatments. A. ocellatus larvae fed on Artemia sp. nauplii tended to better resistant and weight than others that received artificial microdiet. P. mesopotamicus larvae showed better stress resistance and weight values when fed on Artemia sp. or under mixed feeding (Artemia sp. + artificial microdiet). For P. coruscans, the use of forage fish larvae provided more resistant individuals than those treated with Artemia sp. or artificial food. However, values of weight were the same for both foods. The live food is important in the growth in weight as well as in the improvement of the stress resistance in the studied species.

Dois experimentos foram conduzidos utilizando um delineamento inteiramente casualizado, com seis tratamentos e três repetições, para avaliar o efeito de misturas vitamínicas (MV) na larvicultura do jundiá (Rhamdia quelen). Em ambos os experimentos as rações utilizadas foram isoprotéicas (34%PB) e isocalóricas (3.500kcalED/kg). No experimento I adicionou-se MV formuladas, com ou sem suplementação de inositol e/ou vitamina C. Neste experimento a MV T2 proporcionou maior crescimento das larvas. Esta MV foi então testada em seis níveis de inclusão (2,0; 1,5; 1,0; 0,5; 0,25 e 0%) no experimento II. Comprovou-se que a composição em vitaminas da MV apresentada no T1 do experimento 2 foi a mais eficiente na larvicultura do jundiá.Two experiments were carried out by using a randomized entirely design, with six treatments and three repetitions, to evaluate the effect of vitamin mixtures (VM) in the jundiá (Rhamdia quelen) larviculture. In both experiments were used isoproteic (34%CP) and isocaloric (3.500kcal/kg feed) feeds, where in the experiment I VM was formulated, with or without inositol and C vitamin suplementation. In this experiment MV T2 provided higher larvae growth. The VM was tested in six inclusion levels (2,0; 1,5; 1,0; 0,5; 0,25 and 0%) in the experiment II. It was conclude that the vitamins inclusion on the VM utilized in T1 on the second experiment shown to be more efficient in the jundiá larviculture.

Para verificar o desenvolvimento de larvas de surubim-do-iguaçu (Steindachneridion melanodermatum) alimentadas com diferentes dietas, realizou-se um experimento em delineamento inteiramente casualizado, com cinco tratamentos e quatro repetições, em aquários de 35 L, cada um com 15 larvas (8,35±0,85 mm e 6,75±0,64 mg). Os tratamentos consistiram de cinco programas de alimentação: A - Artemia; R - ração; Z - zooplâncton; A+R - Artemia + ração; Z+R - zooplâncton+ração. Avaliou-se o desenvolvimento das larvas em ambiente iluminado durante 29 dias. Para avaliação da dieta e análise do conteúdo estomacal, a cada três dias foram coletadas larvas em cinco aquários adicionais. Nos tratamentos A+R e Z+R, os pesos médios finais das larvas foram significativamente maiores (659 e 571 mg) que nos outros tratamentos. A combinação de alimentos possibilitou os melhores resultados e, no tratamento R, a sobrevivência foi de 1,7%, diferindo dos demais. O canibalismo foi superior no R e no Z, que apresentaram taxas de 60 e 25%, respectivamente. O fornecimento de Artemia em associação à ração promoveu melhor desenvolvimento e maior sobrevivência às larvas de Steindachneridion sp.An assay was conducted to evaluate the development of Iguaçu surubim (Steindachneridion melanodermatum) larvae fed different diets. The experiment was analyzed as a complete randomized design with five treatments and four replicates, in 35 L-aquaria, each one with 15 larvae (8.35±0.85 mm and 6.75±0.64 mg). The treatments consisted of five feeding programs: Artemia (A); diet (D); zooplankton (Z); Artemia with diet (A+D); and zooplankton with diet (Z+D). Larvae development was evaluated in illuminated environment during 29 days. For larvae feeding evaluation, three larvae were collected every three days, in five additional aquaria for stomach content analysis. In the A+D and Z+D treatments, the larvae average weight (659 and 571 mg) was significantly higher than the other treatments. The combinations of feeds resulted in better results and, in treatment R, it was observed survival rate of 1.7, that differs from the other treatments. Cannibalism rate was higher in D and Z treatments, with values of 60 and 25%, respectively. The A+D treatment provided the best development and the highest survival rate for Steindachneridion sp larvae.

Coral reef fish are collected from the wild and exhibited in aquaria worldwide. Some of the fish spawn in captivity; however, the eggs are usually neglected. In this study, we collected the eggs spawned naturally in the exhibit tanks, hatched and cultured them indoor in 2000-L fibreglass tanks (initial density = 18 000 egg tank−1). We applied an inorganic fertilization method commonly used in freshwater fish culture in raising these coral reef fish larvae. We maintained inorganic phosphorus concentration at 100 μg P L−1 and inorganic nitrogen at 700 μg N L−1 daily in the fertilized group ( n = 4), while the control tanks ( n = 4) were fed with rotifers (10 ind mL−1). Chlorophyll a at particle sizes of both 0.45-20 μm and >20 μm, as well as NH3-N, NO3-N, and PO4-P concentrations were significantly higher in the fertilized group than the control. Zooplankton in the size groups of 10-50 μm (mainly flagellates) and 50-100 μm (mainly ciliates) were abundant (about 10~60 ind mL−1) during 3-7 days in fertilized tanks. The average larval fish survival rate at 21 day after hatch in fertilized group was consistently higher than the control in two trials. The experiments demonstrated that the inorganic fertilization approach can be successfully adapted for coral reef fish culture in an aquarium to achieve sustainable exhibits. [ABSTRACT FROM AUTHOR]