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This study evaluated the pharmacokinetic profile of basil (Ocimum basilicum) essential oil (EO) in juvenile tambaqui (Colossoma macropomum). In trial I, juvenile tambaqui (119.9 ± 9.2 g) were exposed to 800 mg L−1 of EO for 10 min for anesthetic induction. After the blood samples, muscle and brain tissue samples were collected at 2, 4, 6, 8, and 10 min to determine the absorption time and distribution of methyl chavicol and linalool, the major compounds in the EO, the concentration of lactate and ammonia in the muscles, and the plasma levels of lactate, chloride, ammonia, and total calcium. In trial II, anesthetic induction occurred at the same time and concentration and blood, muscle, and brain tissue samples were collected at 0.0, 0.5, 1.0, 3.0, and 6.0 h to quantify the elimination of methyl chavicol and linalool and for a histological evaluation of the gills, liver, and spleen. In assay I, both compounds were identified in the plasma, muscle, and brain as early as 2 min, with maximum concentrations observed within 6 min. In assay II, the half-life of methyl chavicol and linalool in plasma was 0.30 h and 0.46 h, respectively. The half-life of methyl chavicol and linalool in muscle was 1.59 h and 0.32 h, respectively, and the half-life of methyl chavicol and linalool in the brain was 0.69 h and 0.33 h, respectively. The histological lesions observed in the gills between 0 and 3 h were reversible, with organ recovery 6 h after anesthesia induction. There were no changes in the liver and spleen during the times evaluated. The biochemical and pharmacokinetic results in this study confirm that the EO of O. basilicum at 800 mg L−1 is a safe anesthetic for tambaqui, inhibits the stress response, and is eliminated rapidly from the fish. [ABSTRACT FROM AUTHOR]

Summary: The objective of this study was to evaluate the effects of cold and room‐temperature storage on the quality of Colossoma macropomum sperm. The experiment was carried out in December (end of Spring), in Nova Mutum‐MT, Brazil, involving nine C. macropomum males (4 years old; 6.4 ± 1.5 kg average weight). The fish were selected and transferred to masonry tanks (4 m3) in a laboratory (water renewal rate: 10 L/s; average water temperature: 28°C). Subsequently, reproduction was induced using 2.5 mg of crude carp pituitary extract/kg and the semen was harvested 240 degree hours after hormonal induction. The following sperm characteristics were analyzed every 5 hr using ImageJ/casa software: total motility (MOT), curvilinear velocity (VCL), average path velocity (VAP), straight‐line velocity (VSL), straightness of sperm path (STR), wobble (WOB), progressive motility (PROG), beat cross frequency (BCF) and total number of spermatozoa (NSPZ). A fresh sample of semen from each animal was kept at room temperature (25.3 ± 1.2°C). For analysis of cooled semen, syringes were kept in cooling boxes at an average temperature of 16.9 ± 2.1°C. The reduction (p < 0.05) of MOT in semen kept at room temperature occurred at 10 hr (13.95%); in cooled semen, however, MOT declined at 15 hr (76.87%). At 15 hr, there was practically no MOT in the semen kept at room temperature (0.20%), whereas in the cooled semen this situation was observed only at 35 hr (2.91%) The MOT of cooled sperm was higher (p < 0.05) at all times (except zero time), compared with the semen maintained at room temperature. At 15 hr, the cooled spermatozoa showed higher (p < 0.05) VCL (142.18 μm/s) and BCF (29.72 Hz) than those maintained at room temperature (VCL: 51.18 μm/s; BCF: 19.57 Hz). After 15 hr, only the cooled sperm showed quality. In conclusion, semen cooling allows for extending the viability of C. macropomum spermatozoa from 5 to 10 hr without compromising their quality in most characteristics. At 15 and 25 hr of cooling, sperm viability is still observed, though with decreased quality. [ABSTRACT FROM AUTHOR]

The objective of this work was to evaluate the semen characteristics of C. macropomum fish from three successive semen sample collections taken during the same reproductive cycle. Six breeders (6.4 ± 1.5 kg) induced with crude carp pituitary extract (2.5 mg kg−1) were used. Samples of semen were collected in graduated syringes after a period of 260 degree-hours. The semen was collected from the same males in September 2014 (sample 1), December 2014 (64 days after the first collection - sample 2) and February 2015 (86 days after the second collection - sample 3). The semen volume was higher ( P < 0.05) in the sample 1 (6.7 mL) and sample 2 (3.4 mL) than in the sample 3 (1.0 mL). Sperm concentration and normal sperm did not significantly differ between samples. Likewise, sperm motility, curvilinear velocity, displacement velocity, oscillation and beat cross frequency did not vary, whereas straight-line velocity, straightness and progression were higher ( P < 0.05) in sample 2 (December). In general, despite lower amounts, the semen appeared to be of good quality for all three samples collected during the same reproductive period. [ABSTRACT FROM AUTHOR]

The aim of the present study was to evaluate induced reproduction in Colossoma macropomum females at the beginning of the reproductive period and 75 days after the first spawning in which reproduction was induced. The experiment was conducted in Nova Mutum, MT, Brazil. Eight 4-year-old C. macropomum females with an average body weight of 6.7 ± 2.4 kg were used. Hormonal induction was performed at the beginning of the reproductive period and repeated 75 days after the first spawning. The following variables were then evaluated: weight of released oocytes, production index, absolute fecundity, oocyte diameter, fertilization rate, and hatching rate. Of the eight females that spawned during the first hormonal induction, three (37.5%) spawned again 75 days after the first spawning. Two females died after the first induced spawning. None of the means of the evaluated variables differed between the two induced spawnings, except for fertilization rate, which was greater ( P  <  0.05) with the first spawning (88.8 ± 6.1%) than in the second (74.1 ± 10.4%). The results of the present study indicate that C. macropomum females can reproduce again 75 days after a first induced spawning. [ABSTRACT FROM AUTHOR]

The aim of this study was to evaluate the efficiency of the hormonal inducers Ovopel ® and carp pituitary extract (CPE) for induction of reproduction in Colossoma macropomum females. The treatments were CPE at the dose of 5.5 mg/kg divided into two applications (10%; and 90% after 12 h) and Ovopel ® at doses of 0.2 and 0.4 pellet/kg body weight in a single application. Eight replicates were used in each of the three treatments, totaling 24 experimental units. The females spawned when treated with the 0.2 pellet of Ovopel ® (100.0%), 0.4 pellet of Ovopel ® (62.5%), and CPE (87.5%), but there were no significant differences among the treatment groups in spawning rate. When there was treatment with Ovopel ® spawning occurred with greater ( P  < 0.05) degree-hours (average water temperature × number of hours until spawning; 0.2 pellet: 417.7; 0.4 pellet: 412.3) in relation to the CPE treatment (268.9). The total oocyte weight was similar when there was treatment with Ovopel ® (0.2 pellet: 832.3 g; 0.4 pellet: 798.9 g) and CPE (688.3 g). By contrast, the production index was greater ( P  < 0.05) with the Ovopel ® treatments (0.2 pellet: 8.8%; 0.4 pellet: 9.0%) as compared with CPE (6.7%). Fertility and hatching rates were similar among the treatment groups. Ovopel ® and CPE are efficient in induction of reproduction in C. macropomum females. Of the two Ovopel ® treatments assessed in this study, the dose of 0.2 pellet/kg body weight is sufficient for effective induction of reproductive processes. [ABSTRACT FROM AUTHOR]

The objective of this study was to evaluate Ovopel and carp pituitary extract (CPE) in the reproductive induction of Colossoma macropomum males. Nine treatments were tested in triplicate, totaling 27 experimental units. C. macropomum breeders were subjected to the following treatments: 0.1, 0.2, 0.3, 0.4, 0.5, 0.6, and 0.7 Ovopel pellet/kg; 2.5 mg CPE/kg (traditional protocol); and a control treatment (no hormone). Breeders under hormone treatment produced a larger (P < 0.05) semen volume (2.4 ± 0.7 to 4.2 ± 0.3 mL) compared with the control (0.9 ± 0.4 mL). Sperm concentration did not differ significantly among treatments (7.2 × 10 9 ± 1.7 to 10.8 × 10 9 ± 2.6 spermatozoa/mL). Total sperm count was higher (P < 0.05) after treatment with 0.3, 0.4, and 0.6 Ovopel pellet/kg (41.6 ± 9.3 to 42.3 ± 10.5 × 10 9 spermatozoa) than the other Ovopel treatments (20.0 ± 2.4 to 26.9 ± 8.2 × 10 9 spermatozoa) and control (6.6 ± 1.1 × 10 9 spermatozoa), but did not differ significantly from CPE (33.7 ± 3.2 × 10 9 spermatozoa). Sperm motility was higher (P < 0.05) in the CPE treated, and 0.2, 0.3, and 0.7 Ovopel pellet/kg (88.3 ± 2.9 to 90.0 ± 5.0) breeders when compared with the other treatments (70.0 ± 10.0 to 78.3 ± 5.8), except for the 0.4 pellet/kg (81.7 ± 2.9) treatment, which did not differ significantly from any of the treatments. The motility period of the spermatozoa did not differ significantly among treatments (93.5 ± 15.7 to 120.0 ± 7.6 s). For the sperm morphological analysis, occurrence of normal spermatozoa was similar across the treatments, with three sperm abnormalities (short tail, bent tail, and detached head) differing (P < 0.05) among the treatments. Ovopel efficiently induced reproduction of C. macropomum breeders, with treatment using 0.3 and 0.4 Ovopel pellet/kg and CPE providing the best semen characteristics. [ABSTRACT FROM AUTHOR]

This study evaluates the performance, morphometric traits, and body yield of the freshwater fish tambaqui, and of the tambatinga and tambacu hybrids. These fish were reared in cages with a 6 m3 usable volume, during three production phases: (I) 0–77 d of rearing (600 fish/cage), (II) 77–264 d of rearing (200 fish/cage), and (III) 264–402 d of rearing (100 fish/cage). In total, 5400 fish from three genetic groups were used in each experimental group (replicated three times). Phase I showed no significant difference in performance between the genetic groups. The exceptions to this were the condition factor and body height, which were highest (p < 0.05) for tambatinga; and specific growth rate and body width, which were highest (p < 0.05) for tambaqui and tambatinga. During phase II, the final weight was higher (p < 0.05) in tambaqui (943.6 g) and tambatinga (686.8 g) than in tambacu (276.4 g). The same was true for other performance traits, whereas the morphometric traits were highest (p < 0.05) in tambaqui. During phase III, tambaqui showed a higher final weight (1764.1 g; p < 0.05) than tambacu (654.8 g), whereas the final weight of tambatinga (906.0 g) did not differ from that of the other genetic groups. The morphometric traits were higher (p < 0.05) in tambaqui than in tambacu in phase III. The evaluated body yield percentages were similar between the groups, with the exception of bone yield, which was highest (p < 0.05) in tambacu. The results showed that during phase II, tambaqui was superior to tambatinga in terms of its morphometric traits, and that it outperformed tambacu in performance and morphometric traits. In phase III, tambaqui achieved greater biomass gains than tambatinga and had better performance and morphometric traits than tambacu. The body yields (with the exception of bones) were similar to those of tambatinga and tambacu. • Tambaqui, tambatinga and tambacu showed equal performance in production phase I. • Tambaqui and tambatinga showed similar performance in production phase II. • Tambaqui and tambatinga showed similar performance in production phase III. • Tambaqui showed greater biomass gain than the other groups in phase III. • Tambaqui, tambatinga and tambacu showed similar body yields. [ABSTRACT FROM AUTHOR]

The present study evaluated the efficacy of Ocimum basilicum (basil) essential oil in the anesthetic induction and recovery of juvenile tambaqui Colossoma macropomum and verified its physiometabolic effects after biometric handling. Juveniles (86.51 ± 7.82 g) were exposed to different concentrations of basil essential oil: 400, 500, 600, 700, 800, 900, and 1000 μL L−1. Subsequently, the fish were divided into five groups: control (non-handled fish), handling without anesthetic (water only), handling with ethanol (720 μL L−1), and handling with Ocimum basilicum essential oil (400 and 800 μL L−1). The shortest (p < 0.05) time to induce anesthesia was at a concentration of 1000 μL L−1 (222 s). The recovery time from anesthesia did not differ significantly among different concentrations (400–1000 μL L−1). The results of the present study confirm the essential oil of O. basilicum as a new and safe natural anesthetic for juvenile tambaqui. The use of this essential oil in biometrics handling procedures reduces or attenuates the secondary responses to handling stress without showing deleterious effects on the non-specific immune system or metabolism of energy, carbohydrates, and lipids. However, further studies are necessary to determine the exact mechanism of action of this essential oil. • The osmoregulatory response in tambaqui was increased by 800 μL L1 of basil. • Basil does not induce hepatotoxicity or liver damage in juvenile tambaqui. • Anesthesia with basil does not alter the anaerobic metabolism of juvenile tambaqui. • Basil promotes anesthesia in tambaqui without impairing cardiorespiratory functions. [ABSTRACT FROM AUTHOR]

• Buserelin acetate induces the reproduction of tambaqui females. • Buserelin acetate can replace carp pituitary extract in the reproduction of tambaqui. • The reproduction of tambaqui with buserelin acetate maintains the quality of oocytes. The aim of this study was to evaluate induced reproduction in tambaqui females using buserelin acetate as compared with the traditional treatment regimen with carp pituitary extract (CPE). Reproductive traits of females with a body weight (BW) of 8.47 ± 1.52 kg were evaluated in ten females treated with buserelin acetate at the dose of 0.5 mL/kg BW, in a single application, and in ten females treated with CPE at the dose of 5.5 mg/kg BW, in two applications (10 % and 90 %, with a 12-h interval between applications). Spawning rate did not differ between the females treated with buserelin acetate (40 %) and CPE (40 %). Weight, fertilization rate and hatching rate did not differ between the two treatment groups. Degree-hours (determined as the average temperature multiplied by time, in hours, for spawning after the treatment with the second dose of CPE and after the single treatment with buserelin acetate) for spawning and number of oocytes per gram of gametes collected were greater (P < 0.05) in the females treated with buserelin acetate than in the females treated with CPE. Production index, absolute fecundity and relative fecundity were greater (P < 0.05) in the females treated with CPE. The hormone buserelin acetate promotes reproduction in tambaqui females with there being a similar spawning rate and oocyte quality, however, lesser production indices and fecundity than when there is the conventional treatment regimen imposed with carp pituitary extract. [ABSTRACT FROM AUTHOR]