Jayme Aparecido Povh

This study evaluated the effects of basil (Ocimum basilicum) incorporation in two forms essential oil and aqueous extract into commercial extruded fish feed. The physical quality of the feed was assessed under four treatments: control (without additives), 0.5% basil essential oil, 0.5% basil aqueous extract, and 0.5% soybean oil. Experimental units consisted of 20 L aquariums, with three replicates per treatment. Additive retention rate was evaluated. Additionally, floating capacity and dry matter leaching tests were conducted in a factorial arrangement involving four treatments and four floating times (5, 10, 20, and 30 minutes), with three replicates. The results showed that basil essential oil and soybean oil presented higher (P<0.05) retention rates (97.51% and 97.14%, respectively) than the basil aqueous extract (93.96%). The floating test over time showed a significant effect (P<0.05) among additives at 10 and 30 min, in which soybean oil exhibited lower floating capacity. No differences were observed in the percentage of dry matter leaching of the feeds as a function of floating time. It was concluded that the incorporation of oil-based additives is more efficient than powder-based additives, as they are better retained and do not impair the physical quality of the feed during water stability.

This study evaluated the effects of dietary supplementation with microencapsulated blackberry anthocyanin extract on pigmentation, antioxidant status, digestive enzyme activity, and histological parameters of black skirt tetra Gymnocorymbus ternetzi . Ninety juveniles were randomly distributed into nine tanks (three tanks per treatment), which were considered the experimental units: a control diet and diets supplemented with 1000 or 2000 mg kg⁻ ¹ microcapsules for 30 days. Survival was 100%, and no differences were observed in final weight, feed intake, or viscerosomatic index; however, fish fed 2000 mg kg⁻ ¹ exhibited a higher condition factor. Supplementation reduced lightness (L*), resulting in darker body coloration. Amylase and alkaline phosphatase activities increased significantly, while hepatic alanine aminotransferase activity decreased in supplemented groups. Histological analyses revealed improved liver architecture and increased intestinal villus height, accompanied by enhanced goblet cell activity. Antioxidant enzyme activities (SOD and CAT) decreased in supplemented groups, suggesting a modulation of antioxidant responses associated with anthocyanin supplementation. Overall, dietary inclusion of microencapsulated blackberry anthocyanins may promote enhanced pigmentation, improved digestive function, modulation of antioxidant-related biomarkers, and preservation of hepatic and intestinal integrity, supporting its use as a natural functional additive in ornamental aquaculture.

Leiarius marmoratus, Zungaru jahu, and Phractocephalus hemioliopterus are large South American catfish species of high commercial and environmental value. This study aimed to evaluate the effect of trehalose solutions at different concentrations (25, 50, 75, and 100 mM), used as activating media, on sperm kinetic parameters over time (10 to 60 seconds post-activation). Sperm from L. marmoratus (n = 4), Z. jahu (n = 2), and P. hemioliopterus (n = 4) were collected following hormonal induction. A pooled sperm sample per species was activated with trehalose solutions and distilled water (control). Sperm kinetics were assessed using a Computer Assisted Sperm Analyzer (CASA). Mean sperm volumes were 0.78 ± 0.17 mL for L. marmoratus, 0.5 ± 0.2 mL for Z. jahu, and 2.4 ± 0.9 mL for P. hemioliopterus. In L. marmoratus, 50 and 75 mM trehalose solutions significantly improved motility duration, percentage, velocity, and progression compared to water. Similarly, 50 and 75 mM trehalose prolonged Z. jahu sperm motility, particularly after 40 seconds, although no significant effect was observed in the first 30 seconds. For P. hemioliopterus, higher trehalose concentrations (75 and 100 mM) increased sperm velocities and progression while reducing motility; thus, distilled water and lower trehalose concentrations (25 and 50 mM) solutions proved more effective. Trehalose solutions containing 50 and 75 mM are recommended for L. marmoratus and Z. jahu sperm activation. For P. hemioliopterus activating sperm, distilled water is better indicated, and trehalose solutions containing more than 50 mM should be avoided.

The objective of this study was to describe the morphological and morphometric characteristics of spermatozoa from four native fish species using a descriptive approach. Semen samples from adult individuals of Pseudoplatystoma reticulatum, Pseudoplatystoma corruscans, Phractocephalus hemioliopterus, and Hemisorubim platyrhynchos were analyzed. Spermatozoa were fixed and examined by scanning electron microscopy (SEM), and the obtained images were subjected to morphometric analysis using ImageJ software (National Institutes of Health, USA). The sperm cells exhibited typical features of primitive aquasperm, lacking an acrosome and consisting of a head, midpiece, and flagellum, and were classified as complex anacrosomal uniflagellate aquaspermatozoa. Among species, relevant morphometric differences were observed, with greater flagellum length in P. reticulatum; larger head and midpiece volume in P. corruscans; a wider and more compact head in H. platyrhynchos; and greater midpiece and flagellum thickness in P. hemioliopterus. These findings contribute to the understanding of the reproductive biology of these species and provide valuable support for ex situ conservation strategies and the improvement of reproductive protocols.

This study evaluated the toxicity of cryoprotectants and the performance of low-rate freezing protocols for oocytes and embryos of Piaractus brachypomus, a Neotropical fish of increasing relevant for Brazilian aquaculture and genetic conservation. Eight cryoprotectant solutions based on methanol (MeOH) or dimethyl sulfoxide (Me2SO), combined with 0.25 M sucrose in L-15 or HBSS media, were tested for oocytes toxicity at 28 °C and post-freezing viability. In spite of histological and scanning electron microscopy (SEM) analyses indicated preservation of gross morphological features, none of the cryopreserved oocytes supported embryonic development, indicating loss of functional viability following cryoprotectant exposure and freezing. For embryos, two low-rate freezing protocols were evaluated: Protocol 1 (P1E), based on gradual cooling to −13 °C, and Protocol 2 (P2E), involving linear cooling to −60 °C followed by storage in liquid nitrogen. In P1E, eight treatments using 3.1 M MeOH combined with different concentrations of polyvinylpyrrolidone (PVP) or sucrose were tested. The highest proportion of morphologically viable embryos (15.3%) was obtained with MeOT + 0.45 M sucrose (SC5), which different significantly from the other treatments. In contrast, no morphologically viable embryos were recovered after P2E, likely due to inadequate dehydration and intracellular ice formation. Overall, high concentrations of permeant cryoprotectants and prolonged equilibration times were detrimental to oocyte and embryo viability, while sucrose showed better cryoprotective performance than PVP. Even though protocols tested were insufficient to ensure consistent post-thaw viability, the partial success observed in P1E under MeOH and sucrose combinations provides a relevant experimental basis for future refinement of conservation strategies and contributes to development of ex situ germoplasm conservation approaches for P. brachypomus and other Neotropical species.

Surgical techniques in aquatic species are underdeveloped, despite these species comprising a significant superclass among vertebrates. In the context of species preservation, studies involving the use of reproductive tissues typically involve the euthanasia of donors. Thus, in animals at high risk of extinction, the practice of sacrificing them presents a point of contradiction between ex situ conservation efforts. The objective of this study was to compare the viability of spermatogonia stem cells (SSCs) collected from Brycon orbignyanus using conventional methods (euthanasia) versus a surgical procedure. Lateral celiotomy was performed on 27 immatures males to obtain a portion of gonadal tissue. The fish were divided into three groups (n=9), with each group receiving polyglactin 910, polyester, or catgut sutures, respectively, for celiorrhaphy. Dermorraphy was performed using nylon sutures in all groups. A. An additional euthanasia group consisted of nine animals exposed to 20 mg/L of propofol. The survival rate over a 48-hour period was 100% for the polyglactin 910 group and 77.7% for the polyester and catgut groups. Additionally, the viability of SSCs was similar between the euthanasia and surgical procedures. The lateral celiotomy technique is feasible for obtaining SSCs in fish with laterally compressed anatomy, such as B. orbignyanus. Additionally, the technique allows the preservation of SSCs as a model for endangered fish species.

This study aimed to develop a bioeconomic simulator consisting of interconnected spreadsheets, such that after the entry of data (inputs), it can perform calculations and present economic, financial, and productive indicator results. To test the functionality of the developed tool, two scenarios were established. In Scenario 1, the reproduction occurred in haps, comprising of egg collection in the buccal cavity of the matrix and the subsequent incubation of the eggs being fertilized in the laboratory. In Scenario 2, a nursery structure was considered for reproduction with post larvae cloud collection. The simulator proved to be functional and the results were significant. In the Statement of Economic Results, the net incomes gained was US$1,958,281 and US$620,592 for Scenarios 1 and 2, respectively. In the context of productive indicators, Scenario 1 presented the best results with 114 million/cycle, with a revenue/cycle of US$1,359,510 and labor cost/thousands of US$1,434. Among the financial indicators contained in the simulator, Scenarios 1 and 2 presented a benefit/cost ratio of 1.11 and 1.01 and profitability indices were 1.48 and 1.04 respectively. The internal rate of return was 17.82% and 8.95% for Scenarios 1 and 2, respectively. The net present value was US$8,165,554 and US$600,337 for Scenarios 1 and 2, respectively, with a payback period of 6 and 10 years, respectively. Both the scenarios provide suggestions for producers looking for a profitable business. The simulator can be used as an auxiliary tool in the study of tilapia reproductive systems to indicate the potential forms of production.

The aim of this study was to evaluate the pharmacokinetics of eugenol in pacu (Piaractus mesopotamicus) juveniles following exposure to an immersion bath. Pacu juveniles (n = 42) with an average weight of 546.40 ± 74.51 g and total length of 25.43 ± 1.52 cm were subjected to a bath with 100 mg L⁻¹ eugenol previously dissolved in 95% ethanol (1:10). After a 10-min immersion, the fish were transferred to anesthetic-free aquaria for recovery. Blood, kidney, muscle, spleen, gills, and brain samples were collected at intervals 0, 0.5, 1.0, 3.0, 6.0, 12.0, and 24.0 h post-anesthesia. Pharmacokinetic parameters were calculated using non-compartmental methods. The highest eugenol concentrations were recorded immediately after anesthesia (0 h) in all tissues, in descending order: plasma > kidney > muscle > spleen > gills > brain. The plasma and brain half-lives of eugenol were 1.12 h and 0.73 h, respectively, with elimination constants of 0.62 and 0.95 per hour. In muscle and kidney tissues, the half-lives were 0.14 h and 0.09 h, with elimination constants of 4.97 and 7.44 per hour, respectively. In the spleen and gills, the half-lives were 0.21 h and 0.23 h, with elimination constants of 3.26 and 3.07 per hour. In conclusion, eugenol is rapidly absorbed and eliminated in growing phase pacu, reaching peak concentrations soon after anesthesia and showing a significant reduction up to 24 h.

The objective of this study was to evaluate the reproductive performance of Nile tilapia (Oreochromis niloticus) in successive spawnings maintained in biofloc technology (BFT). A total of 30 broodstock (females: 29.1±67.39 g and 25.9±1.84 cm; males: 31.4±62.47 g and 27.4±1.93 cm) were distributed into five experimental units, each with a volume of 1 m3, containing six broodstock at a sex ratio of 2:1 (4 females:2 males). The experimental period was five weeks. Water quality were monitored and kept for the species in BFT, with an average temperature of 28.59 ± 0.22 ºC, settleable solids below 50 mL/L, and alkalinity above 100 mg/L. Among the 11 females (55.0%) that spawned for the first time, seven (63.6%) spawned again, with intervals ranging from 14 to 27 days between spawnings. No changes were observed in the reproductive variables, except for a reduction in the minor egg diameter in the second spawning. These results indicate that rearing Nile tilapia females in BFT promotes successive spawnings within a short period, suggesting it is a viable and efficient alternative to the traditional breeding system using hapas installed in earthen ponds.