Wild fish domestication can be considered a strategic approach to endangered species conservation, supporting studies and reducing economic and environmental costs. Three of the most important strategies in the domestication processes of fish are the adaptation of wild fish to captivity, the reproduction of the adapted fish and the production and maintenance of the young individuals. That being said, the present study is divided in three experiments: the 1st aimed to adapt wild Pseudopimelodus mangurus to captivity environment using different feeding approaches and a prophylactic strategie; the 2nd aimed to reproduce the adapted individuals from the 1st experiment; and the 3rd aimed to train the P. mangurus juveniles to accept commercial diets. The 1st and 2nd experiments were successful at the maintenance and artificial reproduction of P. mangurus kept in tanks between the reproductive seasons. The results suggest that the reproductive performance of animals kept in captivity (initial relative fertility-IRF = 609.25 ± 36.6 eggs/g) was similar (p > 0,05) to the performance found in wild individuals (IRF = 679.21 ± 45.66 eggs/g). Feed training of P. mangurus juveniles (3rd experiment) was also conducted, evaluating three feeding treatments with different concentrations of bovine heart and ration. At the end of the experiment, the treatment containing half bovine heart and half commercial feeding resulted in the highest values of weight gain (0.10 ± 0.16 g), specific growth rate (0.37 ± 0.11 mm), length (47.78 ± 2.35 mm) and growth (2.15 ± 2.27 mm), suggesting reasonable acceptability to artificial diets in the cultivation of this species. As conclusion, the present study contributes with the development of techniques for the domestication of fresh water fish species with commercial value or andangered of extinction, showing the domestication and reproduction of wild P. mangurus in captivity. However, more studies have to be conducted in order to improve the acceptance of artificial feeding by juveniles and to increase their survival rate.

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This study aimed to describe a procedure for sampling, reproduction, and first feeding of the Neotropical catfish Pseudopimelodus mangurus, an endangered fish species. Wild adult P. mangurus specimens were collected in the Mogi Guassu River and subsequently induced to spawn in laboratory conditions. After hand-stripping, the females, the average weight of the oocytes was 143 ± 1.6 g, with a fecundity of 718 ± 49.8 oocytes g-1. The diameter of the oocytes non-hydrated was 1,226.3 ± 47.7 μm to 1,761.2 ± 26.4 μm after hydration. The fertilization rates were 98.00 ± 0.63%, and the hatching rate was 68.94 ± 11.83%. The first feeding was made three days post-hatching with six different treatments, in which the best results arose with sequential feeding with Artemia nauplii, Astyanax altiparanae and Prochilodus lineatus larvae. This condition resulted in a final length of 2,012.7 ± 44.8 μm by the 10th day of the experiment, higher survival (65 ± 0.9%) and lower cannibalism rate (14 ± 0.3%). The data obtained in this study is important for the establishment of reproductive biotechniques, mass production of P. mangurus, and future establishment of ex-situ GenBank.

Primordial germ cells (PGCs) are responsible for the generation of all germ cells, and therefore, they are essential targets to be used as a tool for the production of germline chimera. The labeling and route of PGCs were evaluated during the initial embryonic development of Pseudopimelodus mangurus, using whole-mount in situ hybridization (WISH) and mRNA microinjection in zygotes. The WISH method was synthesized a specific RNA antisense probe using part of the coding region from P. mangurus nanos3 cDNA. The RNA microinjection was performed using the GFP gene reporter regulated by translation regulatory P. mangurus bucky ball and nanos3 3’UTR sequences, which are germline-specific markers used to describe in vivo migration of PGCs. The nanos3 and bucky ball gene expressions were evaluated in tissues for male and female adults and initial development phases and larvae from first to seventh days post-hatching. The results from the WISH technique appointed to the origin of PGCs in P. mangurus from the aggregations of nanos3 mRNA in the cleavage grooves and the signals obtained of nanos3 probes corresponded topographically to the migratory patterns of the PGC reported for other fish species. The microinjection of GFP-nanos3 3'UTR mRNA in the zygotes of P. mangurus was not successful for PGC labeling, but it was possible to identify three embryos injected, presenting 3 to 5 evidence of possible PGC labeled in the hatching phase. The nanos3 and bucky ball gene expression was reported in the female gonads and from fertilized eggs until the blastula phase. These results provide information about the PGC migration of P. mangurus and the possible use of PGCs for the future generation of germline chimera to be applied in the conservation efforts of Neotropical Siluriformes species, contributing to the establishment of genetic banks, manipulation of organisms, and assisting in biotechnologies such as the transplantation of germ cells in fish.