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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]

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]

Symbiotics are a combination of prebiotics and probiotics that positively affect the animal by stimulating health-promoting bacteria and thus improving production performance and animal welfare. The aim of this study was to evaluate a water symbiotic on the performance, hematological parameters and intestinal morphometry of Nile tilapia raised in a biofloc technology system (BFT) for the initial grow-out phase. Eighty juveniles (initial weight: 30–35 g) were stocked in eight 100-L tanks (10 fish/box). The fish were evaluated using BFT with and without symbiotics. The symbiotic was added directly to the water on a weekly basis at a dose of 0.2 mg L−1 (commercial recommendation for the product). The experiment was laid out in a completely randomized design with two treatments (BFT with symbiotics and BFT without symbiotics) and four replicates, totaling eight experimental units. The experimental period was 40 days. Final weight, weight gain and the specific growth rate were higher (p <.05) in the fish produced in BFT with symbiotics (77.28 ± 0.61 g; 46.79 ± 0.64 g; 2.33 ± 0.03%) than in those farmed in BFT without symbiotics (73.31 ± 0.73 g; 42.54 ± 0.77 g; 2.17 ± 0.04%). Feed conversion ratio was higher (p <.05) in the group reared in BFT without symbiotic (1.02 ± 0.01) as compared with those farmed in BFT with symbiotics (0.94 ± 0.01). Overall, hematological conditions were better (p <.05) in the fish grown in BFT with symbiotics. There were no major differences in intestinal morphometry between treatments. The inclusion of symbiotics in BFT improved the performance and hematological parameters of Nile tilapia in the initial phase (30 to 77 g) without causing significant changes in intestinal morphometry or intestinal cell density. • The use of symbiotics in BFT improved the performance of Nile tilapia juveniles. • The use of symbiotics in BFT improved the hematological parameters of Nile tilapia. • The concentration of nitrite in the water was reduced in the symbiotic treatment. [ABSTRACT FROM AUTHOR]