The Amazonian symbol fish Arapaima gigas is the only living representative of the Arapamidae family. Environmental pressures and illegal fishing threaten the species’ survival. To protect wild populations, a national regulation must be developed for the management of A. gigas throughout the Amazon basin. Moreover, the reproductive genetic management and recruitment of additional founders by aquaculture farms are needed to mitigate the damage caused by domestication. To contribute to the sustainable development, we investigated the genetic diversity of wild and cultivated populations of A. gigas and developed a panel composed by 12 microsatellite markers for individual and population genetic tracing. We analyzed 368 samples from three wild and four farmed populations. The results revealed low rates of genetic diversity in all populations, loss of genetic diversity and high inbreeding rates in farmed populations, and genetic structuring among wild and farmed populations. Genetic tracing using the 12 microsatellite markers was effective, and presented a better performance in identifying samples at the population level. The 12-microsatellite panel is appliable to the legal aspects of the trade of the A. gigas, such as origin discrimination, reproductive genetic management by DNA profiling, and evaluation and monitoring of genetic diversity.

The present study evaluated the genetic variability of the broodstocks of tambaqui hatcheries in the Brazilian state of Pará. Samples were obtained from the caudal fin of 110 broodstocks from one hatchery in each of four municipalities (Santarém, Peixe-Boi, Breu-Branco, and Ulianópolis), representing all the individuals of each hatchery stock. The samples were genotyped using the multiplex system microsatellite markers. Data were used to calculate observed and expected heterozygosity, number of alleles per locus, and allelic richness. The effective population size and inbreeding coefficient were also calculated. The genetic differentiation between populations was evaluated by using F_ST, and population structuring by the most likely number of genetically homogenous populations and Unweighted Pair Group Method (UPGMA); the arithmetic means were based on Nei's. The indices indicated a loss of genetic variability in the broodstocks from Ulianópolis, Peixe-Boi, and Breu-Branco in comparison with wild tambaqui populations, although this was not apparent in the Santarém stock. A moderate level of genetic differentiation was found among the tambaqui broodstocks based on the F_ST estimates, which were reinforced by the structuring found in the Bayesian analysis and UPGMA. This reflects the domestication process, given that no such structuring is found in natural tambaqui populations. This moderate genetic differentiation associated with the loss of genetic variability found in the four tambaqui broodstocks from the state of Pará provides important insights for the development of future programs of genetic improvement, as well as the conservation of the genetic diversity of these stocks.

A broad panel of potentially amplifiable microsatellite loci and a multiplex system were developed for the Amazonian symbol fish species Arapaima gigas, which is currently in high danger of extinction due to the disorderly fishing exploitation. Several factors have contributed to the increase of this threat, among which we highlight the lack of genetic information about the structure and taxonomic status of the species, as well as the lack of accurate tools for evaluation of the effectivity of current management programs. Based on Arapaima gigas’ whole genome, available at the NCBI database (ID: 12404), a total of 95,098 unique perfect microsatellites were identified, including their proposed primers. From this panel, a multiplex system containing 12 tetranucleotide microsatellite markers was validated. These tools are valuable for research in as many areas as bioinformatics, ecology, genetics, evolution and comparative studies, since they are able to provide more accurate information for fishing management, conservation of wild populations and genetic management of aquaculture.

The aim of this study was to evaluate the haemato-biochemical parameters of tambaqui Colossoma macropomum in different growth phases in an integrated culture with açai Euterpe oleracea. For this, 240 juvenile tambaqui with initial average weight and length of 21.8 ± 7.74 g and 11.28 ± 6.88 cm were cultured in an aquaponic system integrated with açai for 180 days. During the period, 108 healthy tambaquis were sampled and categorized into five distinct growth phases. At each growth phase blood aliquots were collected. The first phase being fish with an average weight of 103.1 ± 5.27 g; second phase with 823.4 ± 42.6 g; third phase with 1087.75 ± 16.38 g; fourth phase with 1402.0 ± 76.6 g and fifth phase with 1815.0±65.1 g. Water quality variables remained within acceptable parameters for both cultures. Erythrocyte was significantly lower in the first and second phase. Haemoglobin was significantly lower in fish in the first phase. Haematocrit remained the same from the second phase onwards. MCV was significantly lower in fish with 1815.0 ± 65.1 g. Plasma glucose levels were significantly lower in the first and second phases. Cholesterol, triglycerides, and total proteins were significantly higher in fish of the fifth phase. AST was significantly lower in fish from the third phase when compared to fish from the first and fifth phases. ALT was significantly higher in fish from the first phase when compared to fish from the third, fourth, and fifth phases. The results are important tools for assessing the health and well-being of tambaqui in future research involving aquaponic cultures.

O objetivo deste estudo foi avaliar os parâmetros hemato-bioquímicos do tambaqui Colossoma macropomum em diferentes fases de crescimento em cultivo integrado com açaí Euterpe oleracea. Para isso, 240 tambaquis juvenis, com peso e comprimento médio inicial de 21,8 ± 7,74 g e 11,28 ± 6,88 cm, foram cultivados em sistema aquapônico integrado ao açaí por 180 dias. No período, 107 tambaquis saudáveis foram amostrados e categorizados em cinco fases distintas de crescimento. Em cada fase de crescimento foram coletadas alíquotas de sangue para análises. A 1ª fase avaliou peixes com peso médio de 103,1 ± 5,27 g; a 2ª, peixes com 823,4 ± 42,6 g; a 3ª, peixes com 1.087,75 ± 16,38 g; a 4ª, peixes com 1402,0 ± 76,6 g e a 5ª, peixes com 1815,0 ± 65,1 g. As variáveis de qualidade da água permaneceram dentro dos parâmetros aceitáveis para ambas as culturas. Eritrócitos foram significativamente diminuídos na 1ª e 2ª fase. Hemoglobina foi significativamente diminuída na 1ª fase. O hematócrito manteve-se igual a partir da 2ª fase. O VCM foi significativamente inferior nos peixes com 1815,0 ± 65,1 g. Os níveis de glicose plasmática foram significativamente diminuídos na 1ª e 2ª fases. Colesterol, triglicerídeos e proteínas totais foram significativamente aumentados nos peixes na 5ª fase. AST foi significativamente diminuído nos peixes na 3ª fase, comparado com a 1ª e 5ª fases. ALT foi significativamente aumentado nos peixes na 1ª fase, comparado com a 3ª, 4ª e 5ª fases. Os resultados são ferramentas importantes para avaliar a saúde e o bem-estar do tambaqui em pesquisas futuras envolvendo culturas aquapônicas.