Felipe Pinheiro de Souza

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

ABSTRACT The aim of this study was to determine the genetic diversity and structure of six wild populations of Prochilodus lineatus in Hydroelectric Power Plants (HPP) of the Pardo (HPP Limoeiro – LMO), Mogi Guacu (HPP Mogi-Guacu – MOG), and Tiete (HPP Promissao – PRO, HPP Barra Bonita – BAB, HPP Nova Avanhandava – NAV and HPP Bariri – BAR) rivers. A total of 47 alleles, ranging in size from 118bp to 330bp were found. The results of observed heterozygosity average (0.490 to 0.625) reflected a high intra-population genetic variability. The values of genetic distance (0.149 to 0.773), Fst (0.006 to 0.218), and Nm (1.2 to 4.2) showed that between the populations there is genetic similarity. According to AMOVA there was higher variation within populations than between them. The dendrogram demonstrated the formation of two groups (LMO-PRO-MOG and BAR-BAB-NAV). It was concluded that wild populations had high genetic variability with genetic similarity between them, possibly caused by the restocking program performed in these rivers. Keywords: curimba, microsatellite markers, fish, preservation, genetic variability

Novel Microsatellite Markers for the Invasive Golden Mussel Limnoperna fortunei

ABSTRACT The golden mussel (Limnoperna fortunei), a mollusc originating from Asia, has caused considerable environmental and economic damage in various Brazilian river basins and reservoirs. Genetic studies that focus on characterizing its invasive potential and the feasibility of control measures are required. The present study identified and characterized 13 new microsatellite markers (of which eight were polymorphic) in L. fortunei using enriched genetic libraries. The analysis performed on 48 individuals from three populations identified 32 alleles, ranging from one to seven alleles per locus. The size of the fragments ranged from 172 to 381 bp. The polymorphic information content values ranged from 0.114 to 0.768, with observed and expected heterozygosity values ranging from 0.043–0.938 to 0.123–0.805, respectively. Six loci showed significant deviation from the Hardy–Weinberg equilibrium, possibly influenced by the heterozygous deficit. The microsatellite primers developed will be useful in studies of the genetic diversity and population structure of L. fortunei and will also contribute to the adoption of control measures for this invasive species in Brazilian and other South American basins.

Parental contribution of Curimba offspring in different reproductive system

The knowledge of appropriate reproductive managements is fundamental for the management and orientation of activities in restocking centers. The aim of the present study was to evaluate the influence of artificial and semi-natural reproductive systems and sex ratios on parental contribution progeny of Prochilodus lineatus. Samples of caudal fins from 25 breeders subjected to the artificial reproductive system and 10 breeders subjected to the semi-natural reproductive system were collected in different sex ratios (1♂:1♀ and 2♂:1♀, and 1♂:1♀, respectively). Two hundred and eight fingerlings from these matings were evaluated. Breeding mortality was recorded shortly after reproductive procedures. For paternity analysis, 10 microsatellite loci were amplified. Three breeders died in the artificial reproductive system (two in the 1:1 ratio and one in the 2:1 ratio). In the 1:1 ratio in the artificial reproductive system, one male (M1.4) had a higher contribution in the progeny formation (41.8%), whereas in the 2:1 ratio, four males contributed from 14.5 to 21.7%. Lower reproductive dominance was identified in the semi-natural reproductive system, with values ranging from 22.86 to 25.71% for four males. In the formation of families, both systems demonstrated a reproductive dominance of some couples. So, the semi-natural reproductive system allowed greater homogeneity in the contribution of progeny without losses due to mortality.

A comparative study of four DNA extraction protocols from adductor muscle in golden mussel (Limnoperna fortunei)

The golden mussel, Limnoperna fortunei, is a mollusk native to Southeast Asia and a highly invasive species in South American countries such as Brazil, Uruguay, and Argentina. In order to better understand the biological behavior of the species and develop alternative control methods, genetic studies involving the optimization of DNA isolation procedures are of utmost importance. The objective of the present study was to develop a simple, reproducible, free of contaminants, and cheap protocol to extract DNA from L. fortunei using the adductor muscle of the mussel as the source. Four DNA extraction protocols were compared: extraction with SDS and proteinase K (P1); extraction with SDS, proteinase K and phenol (P2); TRIzol extraction (P3); and NaCl, SDS and RNase extraction (P4). DNA concentration (ng μL-1) and purity (at 260/280 nm) were measured using a spectrophotometer. DNA purity and amplification were verified by electrophoresis and PCR, respectively. P1 resulted in samples with low DNA concentrations or without any DNA, as revealed by the quantification and purity analysis; P2 had low efficiency, given the absence of DNA in most of the samples subjected to electrophoresis. On the other hand, P3 showed contamination with proteins, as indicated by an absorbance of <1.8 and by the low-quality electrophoresis results. Finally, P4 resulted in well-defined bands, absorbance between 1.8 and 2.0, and successful amplification by PCR. In conclusion, the extraction protocol P4 is a practical, fast, free of contaminants, and efficient method for the isolation of L. fortunei DNA.

Genetic variability of Prochilodus lineatus in artificial and semi-natural reproduction

Abstract Prochilodus lineatus is a South American fish of great economic and social importance that is impacted by high fishing pressure. Restocking programmes have tried to be effective in recovering natural populations; however, genetic and reproductive methodologies are necessary to make feasible the survival of released fingerlings. The genetic variability of P. lineatus subjected to semi-natural and artificial reproduction was evaluated. Caudal fin samples from 25 breeders subjected to an artificial reproduction were collected at different sex ratios (1♂:1♀ and 2♂:1♀), and 138 fingerlings originated from these spawning. Similarly, samples were collected from 10 breeders (1♂:1♀) subjected to a semi-natural reproduction, and 70 fingerlings were generated from this spawning. Ten microsatellite loci were evaluated, producing 142 alleles. High interpopulation variability for broodstock and fingerlings was observed in both reproductive systems. A deficit of heterozygotes through the inbreeding coefficient (Fis) was obtained. Moreover, a deviation in the Hardy–Weinberg equilibrium of the fingerlings in both systems was detected. Fst values indicated a moderate genetic differentiation in 1:1 artificial reproduction system and low differentiation in 2:1 artificial and 1:1 seminatural reproduction system. Despite the high genetic variability, genetics analyses in the next generations of fingerlings will be necessary considering the likelihood of a decrease in genetic variability.

Performance of hybrid catfish subjected to different protein levels

In this study, we investigated the performance of hybrid catfish (Pseudoplatystoma reticulatum x Leiarius marmoratus) fed with feeds containing 32% or 40% crude protein (CP). We analyzed the performance, yield in whole gutted fish, fillet yield and visceral fat index. The experimental units comprised 108 fish with average initial weights of 272.12 ± 74.71 g (32% CP) and 231.97 ± 87.70 g (40% CP). The experimental period was 182 days. Final weight, body height, body width, yield of whole gutted fish and visceral fat content differed (P<0.05) between treatments, with respective values of 1,016.63 g, 7.17 cm, 6.88 cm, 86.06% and 3.28% for the lower protein level; and 1,152.22 g, 7.67 cm, 7.27 cm, 84.44% and 4.81% for the higher protein level. The treatment with 40% CP promotes better performance of hybrid catfish. However, this treatment reduces the yield of whole gutted fish and increases the visceral fat index.