The objective of our work was to describe a low toxicity cryoprotectant solution that allowed vitreous solid formation. Embryos of Prochilodus lineatus were submitted to sensitivity evaluations of six internal cryoprotectants (dimethyl sulphoxide -glycerol -GLY and 1,2-propanediol -PROP) at concentrations of 1-6 M; and two external cryoprotectants (sucrose -SUC and glucose -GLU) at concentrations of 0.1-1 M for 20 min. The capacity of the cryoprotectant solutions to exchange heat with the medium and to form glassy solids was evaluated by immersing 10 ll of cryoprotectant in liquid nitrogen. The PROP had a high survival rate at all concentrations evaluated, and was the only substance that allowed a vitreous solid formation.Thus, it is concluded that the PROP-6 M was the most adequate solution for embryonic vitrification processes, because heat exchange between the system (PROP 6 M/embryos/liquid nitrogen) was faster than for other cryoprotectants and combinations thereof; has low toxicity, promote high rates of dehydration in short periods, and reach the vitreous state, being a good candidate to be used in the tests of embryonic vitrification.
This study aimed to establish a hormonal induction protocol for spermiation of Brycon cephalus males, using Ala6, Pro9Net-mGnRH + metoclopramide (Ovopel®). Thus, 20 males were used divided into three inductor treatments [⅓ pellet/kg (T1), ⅔ pellet/kg (T2) and 1⅓ pellet/kg (T3)] and one control group (CO), which only received physiological solution applications (0.9% NaCl). All treatments were applied in a single dose. For evaluation of the availability of the treatment, the following seminal parameters were analyzed: seminal volume, subjective spermatic motility, duration of motility, pH, osmolality and spermatic concentration. T3 showed the highest seminal volume (4.66 ± 1.52 ml), and was significantly different in comparison with T1 (2.0 ± 0.9 ml), T2 (3.5 ± 1.3 ml) and CO (2.3 ± 1.2 ml). In relation to spermatic motility, T2 and T3 showed significantly higher levels [5, (81-100%)]. However, T3 showed significantly lower average sperm motility duration than T1, T2 and CO (30 ± 7 s; 28 ± 6 s; 32 ± 8 s, respectively). With regard to the seminal parameters of spermatic concentration, pH and osmolality, no significant variation was verified among treatments. In conclusion, mGnRH + metoclopramide used for hormonal induction of B. cephalus reproduction does not induce changes related to spermatic concentration, pH and osmolality parameters of the seminal fluid and the most adequate doses among tested treatments were ⅔ pellet/kg live fish.
Summary Aiming to provide data on the biology of Leiarius marmoratus, which will aid in its production in captivity, as well as in studies for its preservation in the environment, this work had as objectives: analyze and describe main morphological alterations during larval ontogeny of the species. We analyzed 205 individuals, obtained by induced reproduction (Colpani Pisciculture) and kept in CEPTA/ICMBIO, Pirassununga, São Paulo, Brazil. Analyses were performed from hatching moment to 30th day. The specimens were classified into two periods: larval (Stages: vitelline, pre‐flexion, flexion, post‐flexion) and juvenile. Hatched larvae showed ident chromatophores only at anterior and posterior extremities of yolk sac. The standard length ranged from 2.16 mm (yolk) to 28.84 mm (Youth). Dorsal fin rays were initially observed at flexion stage (12–14 rays). Major alterations occurred during post‐flexion/juvenile stage, when dorsal, pectoral, pelvic, anal, and caudal fins were observed and pigmentation intensified throughout the lateral region, forming bands in the body, one between the end of the head and beginning of dorsal to pelvic fin, and another one beginning at dorsal to caudal peduncle and four longitudinal at the head.
This study aimed to evaluate the vitellogenic transference and incorporation of long-chain polyunsaturated fatty acids (LC-PUFA) into the membranes of Prochilodus lineatus embryos, aiming to increase the permeability to cryoprotectants and resistance to electric fields. One hundred thirty broodstock of P. lineatus were fed with control (C) or fish oil-supplemented diets (FO) for 12 months. The fatty acid (FA) profle was determined using gas chromatography. For the neutral fraction, the FO group had a decrease in monounsaturated fatty acids (MUFA) and an increase in n3PUFA and, n6PUFA. To test for cryoprotectant toxicity, embryos were exposed for 20 min to a cryoprotectant solution of 1,2-Propanediol (Prop) at a concentration of 5 or 6 molar (M). For FO, a reduction in survival of 33.1% was observed in 5 M, and no survival was observed at 6 M. Embryo samples were exposed the six polarized electric fields (3.4-51.6 joules), and with 11.2 J of energy, the control group exhibited reduced survival in 98.3% of the fish, whereas the FO presented superior resistance, exhibiting a survival similar to that of the OJ up to 40.2 J. We conclude that FA were transferred between P. lineatus broodstock to the embryos, with an increase in LC-PUFA resulting in lower survival rates in the cryoprotectant test in the FO group and a greater physical plasticity of FO embryos to electrical field tests. K E Y W O R D Sbiotechnology, cryoprotectants, electric field, fatty acids composition, Prochilodus lineatus, toxicity
This study aimed to describe testicular and its main ducts structure in the yellowtail tetra Astyanax altiparanae, contributing to the knowledge of the region in which semen is produced, storage and released, focusing mainly on the dynamic of germinal epithelium and Sertoli cells during germ cell maturation. Ten sexually mature male A. altiparanae had their testes processed according to the routine protocols to optical microscopy. Moreover, spermatic ducts and tubular compartment of the testes of three specimens were perfused with vinyl resin for gross anatomy and scanning electron microscopy. Astyanax altiparanae testes are paired organs, separated for most of their extension, joining posteriorly in a spermatic duct formed by a squamous simple epithelium. Seminiferous compartment presents anastomosing tubular type organisation, and spermatogonia spread along its extent. Spermatogenesis is of cystic type, and there is no main testicular duct. Spermatogenesis develops in 'waves', from posterior to anterior part of the gonad. Thus, while sperm is storage posteriorly, spermatogenesis keeps maturing germ cells anteriorly, making the germinal epithelium very dynamic, holding Sertoli cells that change their function as a cystic envelope to produce secretions of the seminal fluid and store sperm. Such kind of development is thought to be responsible by the high prolificacy of this species.
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