Ecotoxicological Effects of Silver Nanoparticles (Ag-NPs) on Parturition Time, Survival Rate, Reproductive Success and Blood Parameters of Adult Common Molly (Poecilia sphenops) and Their Larvae

Nanoparticles (NPs) can display toxicological effects on aquatic organisms. This study investigates ecotoxicological effects of Ag-NPs on reproductive and blood parameters of adult common molly (Poecilia sphenops) and their larvae. During the LC50 96 h test, female fish were exposed to concentrations of 0, 5, 15, 25, 35, 45 and 60 mg L−1 of Ag-NPs, while larvae were exposed to 0, 3, 5, 10 and 15 mg L−1. Finally, we aim to evaluate the effects of 0, 5, 10 and 15 mg L−1 of Ag-NPs on parturition time, reproductive success and hematological parameters of the mature fish exposed to sub-lethal concentration during a 62-day period. We also evaluated the survival rate of larvae. The results show a positive correlation between mortality rate and Ag-NP concentration. Values for LC50 96 h in adult fish and larvae were 26.85 mg L−1 and 6.22 mg L−1, respectively. A lack of parturition and reproductive success were seen in fish that underwent chronic exposure to Ag-NPs (15 mg L−1). The results show that RBC, WBC and hematocrit were significantly decreased in fish exposed to Ag-NPs. In addition, the serum concentrations of total protein, albumin, cholesterol and triglycerides were significantly increased in fish submitted to Ag-NPs (concentrations of 5–15). In conclusion, submitting a fish to higher concentration than 10 mg L−1 has adverse effects on reproductive system and blood parameters.

Contribution to a reference library of DNA barcodes of Colombian freshwater fishes

The Barcode of Life initiative was originally motivated by the large number of species, taxonomic difficulties and the limited number of expert taxonomists. Colombia has 1,610 freshwater fish species and comprises the second largest diversity of this group in the world. As genetic information continues to be limited, we constructed a reference collection of DNA sequences of Colombian freshwater fishes deposited in the Ichthyology Collection of the University of Antioquia (CIUA), thus joining the multiple efforts that have been made in the country to contribute to the knowledge of genetic diversity in order to strengthen the inventories of biological collections and facilitate the solution of taxonomic issues in the future. This study contributes to the knowledge on the DNA barcodes and occurrence records of 96 species of Colombian freshwater fishes. Fifty-seven of the species represented in this dataset were already available in the Barcode Of Life Data System (BOLD System), while 39 correspond to new species to the BOLD System. Forty-nine specimens were collected in the Atrato River Basin and 708 in the Magdalena-Cauca asin during the period 2010-2020. Two species (Loricariichthys brunneus (Hancock, 1828) and Poecilia sphenops Valenciennes, 1846) are considered exotic to the Atrato, Cauca and Magdalena Basins and four species (Oncorhynchus mykiss (Walbaum, 1792), Oreochromis niloticus (Linnaeus, 1758), Parachromis friedrichsthalii (Heckel, 1840) and Xiphophorus helleri Heckel, 1848) are exotic to the Colombian hydrogeographic regions. All specimens are deposited in CIUA and have their DNA barcodes made publicly available in the BOLD online database. The geographical distribution dataset can be freely accessed through the Global Biodiversity Information Facility (GBIF).

Acute and Chronic Toxicity of Endocrine Disruptive Heavy Metals and Pesticides Exposed to Freshwater Fish P. reticulata and P. sphenops

Environmental monitoring is a recent world-wide approach to save the future in line. The present study focuses on toxicity of heavy metals and pesticides on the freshwater aquarium fish (Poecilia reticulata and Poecilia sphenops). The study intense on drawing the acute and chronic safe levels of metals and pesticide exposed to 96 h and 28 day respectively. On exposure, the fish were observed to be under stress and showed excitability. It was observed that both species were highly sensitive to arsenic and cypermethrin, meanwhile resistant to cadmium and chlorpyrifos. The acute safe levels for As irrespective of species was comparatively lesser than that of Cd exposed fish and the range of safe values for pesticides exposure were between 0.018 and 0.059 ppb. As the water quality is influencedby many environmental factors, the present study helps the aquarist in monitoring the safe level of toxicants in the medium. This in turn increases the economic growth of the aquarist.

Contribution to a reference library of DNA barcodes for Colombian freshwater fishes

The Barcoding was proposed motivated by the mismatch between the low number of taxonomists that contrasts with the large number of species, the method requires the construction of reference collections of DNA sequences that represent existing biodiversity. Freshwater fishes are key indicators for understanding biogeography around the world. Colombia with 1610 species of freshwater fishes is the second richest country in the world in this group. However, genetic information of the species continues to be limited, the contribution to a reference library of DNA barcodes for Colombian freshwater fishes highlights the importance of biological collections and seeks to strengthen inventories and taxonomy of such collections in future studies. This dataset contributes to the knowledge on the DNA barcodes and occurrence records of 96 species of Freshwater fishes from Colombia. The species represented in this dataset correspond to an addition to BOLD public databases of 39 species. Forty-nine specimens were collected in Atrato bassin and 708 in Magdalena-Cauca bassin during the period of 2010 to 2020, two species (Loricariichthys brunneus and Poecilia sphenops) are considered exotic to the Atrato, Cauca and Magdalena basins and four species (Oncorhynchu mykiss, Oreochromis niloticus, Parachromis friedrichsthalii and Xiphophorus helleri) are exotic to Colombian hydrogeographic regions. All specimens are deposited in the CIUA collection at University of Antioquia and have their DNA barcodes made publicly available in the Barcode of Life Data System (BOLD) online database and the distribution dataset can be freely accessed through the Global Biodiversity Information Facility (GBIF).

Fishes from the Río Alvarado drainage, Upper Río Magdalena Basin, Colombia

An annotated list of the freshwater fishes of the Río Alvarado drainage, Upper Río Magdalena Basin is presented. Fishes were captured from nine localities, quarterly sampled between September 2012 and July 2013. A total of 36 species belonging to 14 families, distributed in five orders were collected. The most abundant species was Trichomycterus banneaui (Eigenmann, 1912) (19.4%), followed by Creagrutus affinis Steindachner, 1880 (13%), Chaetostoma thomsoni Regan, 1904 (9.1%), Trichomycterus mogotensis Ardila-Rodríguez, 2017 (7.7%), Astroblepus homodon (Regan, 1904) (6.6%), Creagrutus dulima Albornoz-Garzón, Conde-Saldaña, García-Melo, Taphorn & Villa-Navarro, 2018 (5.9%), Poecilia sphenops Valenciennes, 1846 (5.7%) and Argopleura magdalenensis (Eigenmann, 1913) (5.6%). An identification key and a complete photographic catalog of all fish species recorded in the drainage are presented.

Detection and genetic analysis of infectious spleen and kidney necrosis virus (ISKNV) in ornamental fish from non-clinical cases: First report from India

Infectious spleen and kidney necrosis virus (ISKNV), a type species of the genus Megalocytivirus, poses a threat to ornamental fish trade as most cases show nonspecific symptoms, thus making timely diagnosis challenging. Apparently health molly (Poecilia sphenops) and angelfish (Pterophyllum scalare) collected from two distinct geographic localities of India were screened for four genera under Iridoviridae, Megalocytivirus {ISKNV, turbot reddish body iridovirus (TRBIV) and red seabream iridovirus (RSIV); ranaviruses and Singapore grouper iridovirus; and Lymphocystivirus} through molecular approach. In total five numbers out of 17 samples (29.4%), ISKNV genome fragments were detected. A PCR assay using major capsid protein (MCP) gene was standardised to detect and differentiate infections within the Megalocytivirus genus, even without aid of sequencing. This forms the first report of ISKNV infection in ornamental fish from India. Sequence analysis of MCP gene showed that Indian isolate being 100% similar to the complete genome or reference strain of ISKNV. Phylogenetic reconstruction demonstrated the present strain belonging to ISKNV genotype I. Furthermore, structural stability of the MCP revealed this strain was more stable than ISKNV genotype II, RSIV and TRBIV at 25 degree C and pH 7.0. Thus a strong pan-India surveillance is recommended to reduce trade risk.

Effects of artificial photoperiod on the body colouration in the ornamental fish poecilia sphenops

In Orange balloon Molly, Poecilia sphenops, the development of chronic stress due to continuous exposure to artificial LED lighting irrespective to photoperiod causes deterioration in the body colour even in the presence of carotenoid rich green water and artificial feed with added additives in the experimental fishtank setup. In the present study, the effects of continuous exposure to lighting and its consecutive development of chronic stress causes the body colouration to fade off in the freshwater ornamental live bearer, Poecilia sphenops, though the fishes were provided with colour enhancing as well as stress relievingfactors. Several trials showed that, whatever may be the colour enhancing agents provided, artificial lighting for long exposure irrelevant to the normal photoperiod remains as a strong anti-colouration as well as stress inducing factor and remains unaffected to any antagonistic factors. To conclude photoperiod is an essentialfactor to be concerned for colour enhancement in Poecilia sphenops.

Expression of Estrogenic Response Genes in Black Mollies (Poecilia Sphenops) Exposed to Pyrogenic Hydrocarbon and Petroleum from Campeche Sound

The estrogenic effects of endocrine disrupting compounds (EDC´s) in animals are not reversible and can reduce populations. Sensitive methods such Q-PCR have been used to determine changes in gene expression and thus predict the effects before they become irreversible. The present study was designed to detect the expression on the estrogen receptors and vitellogenin genes in the Black Mollies fish (Poecilia sphenops) exposed to pyrogenic hydrocarbon and petroleum from Campeche Sound. The results indicate that the expression of transcript of the estrogen receptor and vitellogenin indicates are potentially useful as molecular biomarker for detecting the presence of endocrine-disruption compounds in environment.