ABSTRACT. With the rise of world fish farming, the national scenario is favorable for using native fish for intensive farming. Among the catfish, the Amazonian Jundiá (Leiarius marmoratus) is a robust candidate, easy to grow and with good organoleptic characteristics in its flesh. For productive success in captivity, it is necessary to consider some questions about the species, such as genetic variability, which must have an acceptable level in a breeding stock, in order to maintain a good diversity; this reduces losses due to inbreeding and low diversity. Therefore, the objective of this study was to characterize the genetic variability of commercial stocks of L. marmoratus from the State of Mato Grosso through microsatellite molecular markers. We analyzed 143 individuals from three stocks. The mean heterozygosity and the inbreeding coefficients observed were 0.060; 0.084; 0.141; and 0.539; 0.562; 0.514, respectively, for the stocks of Campo Verde, Juína, and Nova Mutum. The Deviation in the Hardy-Weinberg equilibrium was observed in most of the loci in the three populations. Considering the genetic differentiation, it is concluded that the three populations are very close genetically, which requires introduction of new genetic material in the stocks to enrich them genetically for a later reproductive program.

RESUMO O gênero Brycon compreende um grupo de espécies de peixes de grande importância socioeconômica e biológica no Brasil. Entretanto, o conhecimento genético dessas espécies é escasso, principalmente no caso do Brycon falcatus. Diante disso, objetivou-se verificar a transferibilidade de primers heterólogos em B. falcatus. Foram avaliados primers heterólogos provenientes das espécies B. opalinus, B. hilarii, B. insignis, B. orbignyanus, B. amazonicus, Prochilodus argenteus, Prochilodus lineatus, Piaractus mesopotamicus e Colossoma macropomum. Os primers que demonstraram melhores padrões de amplificação foram aplicados a uma amostra de 22 indivíduos e os parâmetros genéticos foram calculados. Nove primers apresentaram resultados satisfatórios de amplificação cruzada com B. falcatus: BoM5 (Brycon opalinus), Bh8, Bh13 e Bh16 (B. hilarii); Borg59 (Brycon orbignyanus); Bag22 (B. amazonicus); Par12 and Par80 (Prochilodus argenteus) e Cm1A8 (Colossoma macropomum). Os parâmetros genéticos (número de alelos, alelos efetivos, riqueza de alelos e heterozigosidade esperada e observada) e o conteúdo de informação polimórfica (PIC) demonstraram a viabilidade da utilização dos primers para análises genéticas populacionais. Nosso estudo demonstra o potencial de transferibilidade de marcadores microssatélites de espécies relacionadas e até de gêneros diferentes para B. falcatus, fornecendo ferramentas úteis para futuros estudos genéticos populacionais nessa espécie.

ABSTRACT The genusBryconcomprises fish species of significant socioeconomic and biological importance in Brazil. Despite that, the genetic knowledge about these species is scarce, especially regardingBrycon falcatus. Thus, the objective of this study was to evaluate the transferability of heterologous microsatellite primers inB. falcatus for the first time. Heterologous primers obtained from B. opalinus, B. hilarii, B. insignis, B. orbignyanus, B. amazonicus, Prochilodus argenteus, Prochilodus lineatus, Piaractus mesopotamicus, and Colossoma macropomum were evaluated. The primers that showed the best amplification patterns were applied to a sample of 22 individuals and the genetic parameters were calculated. Nine primers displayed satisfactory cross-amplification withB. falcatus: BoM5 (Brycon opalinus); Bh8, Bh13 and Bh16 (B. hilarii); Borg59 (B. orbignyanus); Bag22 (B. amazonicus); Par12 and Par80 (P. argenteus), and Cm1A8 (C. macropomum). The genetic parameters (number of alleles, effective alleles, allele richness, and expected and observed heterozygosity) and the polymorphic information content (PIC) confirmed the viability of these primers for population genetics analyses. Our study demonstrates the potential of transferability of microsatellite markers from related species and even different genera to B. falcatus, providing usefull tools for future population genetic studies in this species.

ABSTRACT This study evaluated morphometric and ultrasound information of tilapia (O. niloticus) breeders through multivariate analysis. We applied correlation, clustering, and principal component analysis to a dataset composed of information from 222 male and female breeders of the improved GIFT strain. The body weight, objective of the breeding program, showed a high positive correlation with most of the morphometric parameters. The formation of clusters indicated characteristics responsible for muscle composition and carcass weight. Some characteristics showed a high correlation, such as body weight and fillet weight (0.98 and 0.94 for females and males, respectively), and a high contribution to the explanation of data variability; of the total characteristics evaluated for females, two explained 75% data variability and four explained 72% for males. We concluded that it is possible to reduce the number of characteristics measured, as well as use information of average daily weight gain and body weight to select female and male breeders, respectively, to drive genetic gains favoring more productive generations.

RESUMO: Brycon gouldingi é uma espécie de peixe neotropical com importância socioeconômica e ambiental na Bacia do Tocantins-Araguaia. Estudos genéticos nessa espécie ainda são escassos, dificultando o conhecimento sobre a estrutura populacional e a diversidade genética nos estoques naturais e em cativeiro. O objetivo do presente estudo foi avaliar a transferibilidade de primers microssatélites heterólogos em B. gouldingi. Foram avaliados um total de 30 primers de oito espécies: Brycon hilarii, Brycon opalinus, Brycon cephalus, Brycon orbignyanus, Prochilodus lineatus, Prochilodus argenteus, Piaractus mesopotamicus e Colossoma macropomum. Os primers que demonstraram melhores padrões de amplificação foram aplicados em 20 espécimes de B. gouldingi para os cálculos dos parâmetros genéticos. Sete dos 30 primers apresentaram resultados satisfatórios de transferibilidade, sendo seis oriundos do gênero Brycon: Bh13 (B. hilarii), BoM5, BoM13 (B. opalinus), Borg9, Borg13 e Borg59 (B. orbignyanus), e um oriundo de P. argenteus (Par80). Os primer das outras espécies testados mostraram inespecificidade ou monomorfismo, sendo excluídos das análises. O número de alelos variou de dois (Borg13 e Borg59) a três (Bh13, BoM5, BoM13, Borg9 e Par80), com tamanhos entre 103 pb (BoM5) e 430 pb (Borg9). Quatro primers apresentaram evidências de alelos nulos (BoM13, Borg9, Borg13 e Par80), o que provavelmente inferiu sobre o desvio de Hardy-Weinberg nos mesmos. Concluindo, sete primers foram validados para a amplificação cruzada em B. gouldingi e poderão ser utilizados em futuros estudos com essa espécie.

ABSTRACT: Brycon gouldingi is a species of neotropical fish of socioeconomic and environmental importance in the Tocantins-Araguaia Basin. Genetic studies on this species are still limited, making it difficult to evaluate the population structure and genetic diversity in natural and captive stocks. Here, we aimed to evaluate the transferability of heterologous microsatellite primers in B. gouldingi. A total of 30 primers for eight species were evaluated: Brycon hilarii, Brycon opalinus, Brycon cephalus, Brycon orbignyanus, Prochilodus lineatus, Prochilodus argenteus, Piaractus mesopotamicus, and Colossoma macropomum. The primers that showed the best amplification patterns were applied to 20 specimens of B. gouldingi, and their genetic parameters were assessed. Among the 30 primers, seven showed satisfactory transferability, six of which belonged to the genus Brycon: Bh13 (B. hilarii), BoM5, BoM13 (B. opalinus), Borg9, Borg13, and Borg59 (B. orbignyanus), and one belonged to P. argenteus (Par80). The primers for the other species tested showed non-specificity or monomorphism; and were therefore, excluded from the analyses. The number of alleles ranged between two (Borg13 and Borg59) and three (Bh13, BoM5, BoM13, Borg9 and Par80), with sizes varying between 103 bp (BoM5) and 430 bp (Borg9). Four primers showed evidence of null alleles (BoM13, Borg9, Borg13, and Par80), which could probably be attributed to the respective Hardy-Weinberg deviation. Thus, seven primers were validated for cross-amplification in B. gouldingi, which may be used in future studies involving this species.

RESUMO: A piracanjuba (Brycon orbignyanus) é um peixe de grande valor econômico que nos últimos anos tem apresentado uma redução drástica em suas populações naturais. Nesse contexto, estudos de variabilidade genética dos estoques naturais e nos programas de repovoamento são fundamentais para adoção de medidas conservacionistas. O objetivo do presente trabalho foi verificar a amplificação cruzada de primers heterologos em B. orbignyanus. Foram avaliados um total de 52 primers das espécies Brycon opalinus, Brycon hilarii, Brycon insignis, Prochilodus sp., Piaractus mesopotamicus, Colossoma macropomum e Oreochromis niloticus. Os primers com melhor reprodutibilidade foram aplicados a uma amostra de 20 indivíduos e os parâmetros genéticos foram calculados. Nove primers apresentaram resultados satisfatórios de amplificação cruzada com B. orbignyanus, sendo das espécies Brycon opalinus (BoM5 e BoM13), Brycon hilarii (Bh5, Bh6, Bh8, Bh13 e Bh16), Brycon insignis (Bc48-10) e Prochilodus argenteus (Par80). Os primers de Piaractus mesopotamicus, Colossoma macropomum e Oreochromis niloticus não apresentaram amplificação ou apresentaram inespecificidade. Os resultados revelaram a possibilidade da utilização de primers de diferentes espécies e gênero em B. orbignyanus, o que facilita a realização de estudos genéticos nessa espécie.

ABSTRACT: Brycon orbignyanus, popularly known in Brazil as piracanjuba, is a fish with great economic value but whose natural population drastically decreased in number during the last years. In this context, genetic variability studies of natural stocks and in restocking programs are fundamental for the adoption of conservation measures. Current analysis verifies the cross-amplification of heterologous primers in B. orbignyanus. Fifty-two primers of the species Brycon opalinus, Brycon hilarii, Brycon insignis, Prochilodus sp., Piaractus mesopotamicus, Colossoma macropomum and Oreochromis niloticus were tested. Primers with the best reproducibility were applied to a sample of 20 individuals and the genetic parameters were calculated. Nine primers provided good results for cross-amplification with B. orbignyanus, involving (BoM5 and BoM13) of Brycon opalinus, (Bh5, Bh6, Bh8, Bh13 and Bh16) of Brycon hilarii, (Bc48-10) of Brycon insignis and (Par80) of Prochilodus argenteus. Primers of Piaractus mesopotamicus, Colossoma macropomum and Oreochromis niloticus failed to provide amplification or provided non-specificity. Results demonstrated the possibility of using primers of different species and genera of B. orbignyanus, facilitating genetic studies on the species.