Genetic diversity of pacu for restocking programs in the Tietê and Grande rivers, Brazil

Abstract

Piaractus mesopotamicus is a tropical fish under threat because of declines in the number of wild populations. Restocking programs have been developed as a conservation method, and the genetic monitoring of populations and broodstocks is important to ensure the viability of such programs. The objective of the current unprecedented experiment was to evaluate the genetic diversity of P. mesopotamicus wild populations (WPs) and broodstocks (BSs) using microsatellites markers for supplying the restocking programs in the Tietê and Grande rivers. Six microsatellite loci were amplified using the DNA obtained from the caudal fin of 279 adult fish. The observed intrapopulation genetic variability was high with mean heterozygosity ranging from 0.203 to 0.833. The number of alleles per locus ranged from three (loci Pme28 and Pme32) to thirteen (loci Pme4, Pme5 and Pme14), and there were allele differences between WPsxWPs and WPsxBSs. This differentiation was confirmed by the dendrogram analysis that showed three specific clusters. Four alleles were shared in the WPs2012xBSs. Positive FIS values indicated the presence of endogamy in seven out of ten samples obtained from the WPs. The AMOVA analysis and FST values indicated moderate and high genetic differences in WPsxWPs and high genetic differences in WPsxBSs. The genetic distance and genetic identity values and number of migrants confirmed these results. Adequate intrapopulation genetic variability, similarity between BSsxBSs, and genetic differences between WPs2011xWPs2012 and WPsxBSs were observed. In the wild, individuals from the restocking program were partially observed. ResumoPiaractus mesopotamicus é um peixe tropical que nos últimos anos tem apresentado uma diminuição no número de populações naturais. Programas de repovoamento vêm sendo utilizados como método de conservação, entretanto, o monitoramento genético das populações e dos estoques de reprodutores é importante para conferir a viabilidade desse tipo de programas. O objetivo do presente estudo foi avaliar de forma inédita a diversidade genética de populações selvagens (WPs) e estoques de reprodutores (BSs) de P. mesopotamicus utilizados em programas de repovoamento dos rios Tietê e Grande, através de marcadores microssatélite. Seis loci microssatélite foram amplificados usando DNA extraído de nadadeira caudal de 279 indivíduos adultos. Foi observada alta variabilidade genética intrapopulacional, com medias de heterozigosidade observada entre 0.203 e 0.833. O número de alelos por locus foi de três (locus Pme28 e Pme32) a 13 (locus Pme4, Pme5 e Pme14) e houve diferenciação de alelos entre WPsxWPs e WPsxBSs. Essa diferenciação foi confirmada pela análise do dendrograma que mostrou a formação de três agrupamentos específicos. Observaram-se quatro alelos compartilhados entre WPs2012xBSs. Valores positivos de F IS mostraram a presença de endogamia em sete das 10 coletas realizadas nas WPs. A análise de AMOVA e do F ST indicou moderada e muito alta diferenciação genética entre WPsxWPs e diferenciação gen...

Genetic diversity in Amazonian Jundiá (Leiarius marmoratus) stocks using heterologous primers

“…Animal Sciences, v. 44, e52657, 2022 The highest value of heterozygosity observed in this study was 0.250 and occurred for the Nova Mutum stock. This value is similar to the one obtained (0.203) by Ribeiro et al (2015) for Piaractus mesopotamicus, used in restocking programs, and it is inferior to the averages obtained with Rhamdia quelen (0.537; 0.500; 0.482) in the work conducted by Goes (2017), using the locus RHQ2. This means that the analysis of heterozygosity is essential for the evaluation of variability in stocks, and according to Moreira, Hilsdorf, Silva, and Souza (2007), the higher the index observed, the greater the differentiation among the individuals of the population in question.…”

Genetic diversity of migratory fish populations of the Rio Grande Reservoir (São Paulo, Brazil)

“…Among the native species of economic importance in this river, Pacu (Piaractus mesopotamicus), Curimba (Prochilodus lineatus), and Piracanjuba (Brycon orbignyanus) are the major long-distance migratory species (WAGNER et al, 2012;IBGE, 2015). Few studies have evaluated the genetic diversity of these species in the Rio Grande, for example, Lopera-Barrero et al 2015and Ribeiro et al (2015), who evaluated P. lineatus and P. mesopotamicus, respectively. In addition, there has been no study on B. orbignyanus populations in this river.…”

“…For B. orbignyanus, PCR was performed according to Castro et al (2017), using eight microsatellite loci: BoM5, BoM13 (BARROSO et al, 2003), Bh5, Bh6, Bh8, Bh13, Bh16 (SANCHES; , and Par80. Finally, the amplification conditions for P. mesopotamicus was according to the methodology described by Ribeiro et al (2015), using seven loci: Pme2, Pme4, Pme5, Pme14, Pme20, Pme28, and Pme32 (CALCAGNOTTO et al, 2001). The reactions were performed on a Veriti® thermal cycler (Applied Biosystems®, Austin, TX, USA).…”

Monitoramento e conservação genética de populações naturais de Prochilodus lineatus dos rios Pardo, Mogi-Guaçu e Tietê, São Paulo

“…Nesse contexto, os programas de repovoamento de peixes nativos estão sendo cada vez mais utilizados como estratégias de conservação (Ribeiro et al, 2015).…”

“…Alguns estudos recentes envolvendo conservação de espécies nativas migradoras têm mostrado resultados efetivos por meio da utilização de marcadores moleculares microssatélites Ribeiro et al, 2015).…”