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Invasive alien species (IAS) exert a negative impact on native ecosystems and on various human activities. Limnoperna fortunei (Dunker 1857), a sessile mytilid introduced from Asia in the Río de la Plata, demonstrates a high dispersal capacity, growing over other organisms and artificial structures. Understanding its behavior is crucial for developing appropriate control and mitigating its detrimental effects. This study investigated the population dynamics of this mollusk in response to urban effluents in a large river. Water and population parameters of L. fortunei were measured both upstream and downstream of a small town from July to December 2020. Downstream areas exhibited increased temperature and decreased transparency compared to upstream locations, while pH, conductivity, and dissolved oxygen remained relatively constant. However, downstream, the L. fortunei population comprised fewer and smaller individuals, displaying high width-to-length ratios. Most measured water parameters exhibited significant differences between sampling months. The abundance of L. fortunei remained relatively stable over time due to its nearly continuous reproduction in Uruguay. Nonetheless, shell elongation (15.3-22.8 mm) coincided with an increase in dry weight (0.009-0.038 g) from winter to spring. Allometric relationships, primarily following a power-law model, varied between months, ranging from H = 0.39L1.04 to H = 1.36L0.57. This study contributes to the comprehension of the population dynamics and life history of L. fortunei, thereby aiding in the conservation of invaded aquatic systems. Moreover, it provides valuable insights into the effects of urban effluents on this species, contributing to our understanding of its potential role as a bioindicator.

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The present study aimed to evaluate and compare feeding responses of the non-native and native bivalves, the dark false mussel Mytilopsis leucophaeata and the scorched mussel Brachidontes darwinianus, respectively, by offering different concentrations of seston from the coastal lagoon where these species coexist after dark false mussel introduction (Rodrigo de Freitas Lagoon, Rio de Janeiro-Brazil). For this purpose, independent laboratory experiments were carried out under five concentrations of seston to test the differences in clearance and ingestion rates of bivalves as a function of increasing concentrations of suspended particulate matter (SPM) on seston. In addition, from the integrated analysis of data obtained in experiments, it can be inferred about the efficiency levels of these species to remove SPM from seston and their effects on water turbidity and nutrient concentrations (total carbon, nitrogen, and phosphorus). Our hypothesis was that the non-native bivalve is more efficient to clear and ingest SPM from seston compared to the native one, which may lead to competitive advantages to the successful invasion of M. leucophaeata in coastal lagoons. Native species did not show a significant difference in clearance and ingestion rates with increasing concentrations of seston. Whereas the non-native bivalve showed a slight tendency to increase its clearance and ingestion rates with the increase in seston concentrations, evidencing its plasticity to adjust its feeding responses. The native bivalve was significantly more efficient to clear and ingest SPM at the lower seston concentration (i.e., close to natural concentrations found in the lagoon) compared to the non-native bivalve, which, on the other hand, showed a significant increase in its ingestion rates at the higher concentration tested (140 mg SPM L-1). Thus, the present results did not suggest food competition between the non-native M. leucophaeata and the native B. darwinianus in the introduced system. However, M. leucophaeata increased its feeding response with experimental increment in seston concentration, which suggests species ability to benefit from conditions of increased inputs of organic matter and higher primary production that could mediate its establishment in introduced systems.

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The golden mussel (Limnoperna fortunei) is an aggressive invasive species in South America, where it endangers native species and freshwater ecosystems, in addition to causing extensive economic losses, mainly to the hydroelectric sector. Currently, there's no efficient control method available and the invasion has progressed across the continent. Its high reproduction rate is one of the key factors of the golden mussel's high invasive potential and, recently, efforts have been done in order to understand the reproduction and the sexual features of this species. However, its cytogenetics characterization is incipient and the possible occurrence of sex-specific cytogenetic features was never investigated. In this study, we aimed to characterize the chromosomal morphometry, the distribution profile of heterochromatin, and to detect possible sex-related epigenetic marks in the golden mussel. Results revealed that the karyotypic structure is similar in both sexes and no chromosome heteromorphism was observed between males and females specimens. The data increment the cytogenetic characterization of Limnoperna fortunei and contribute for future studies that aim to further investigate its reproduction and underlying sex determination processes.

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The study was conducted to compare the distribution and composition of the Molluscs community in 4 ecosystems (4 sites) in southern of Iraq, namely: (Site 1)- in Euphrates River at Al-Madinah city, (Site 2)- in Shatt Al-Arab at Al-Sharsh area, (Site 3)- in the Garmat Ali River at Al-Mashib area and Site 4- in the Al-seba area. Samples were collected from study sites during a period of January to August 2019. (11) species from the class Gastropoda and (4) species from the class Bivalves, species were predominated in most of the study months which are species: Melenodies nodosa, Bellamya bengalensis and Melanopsis turbculata from Gastropoda and two of the species are bivalve: Corbicula fluminalis and Limnoperna fortunei (Dunker, 1857), and the last species, L. fortunei, was recorded in the current study for the first time in freshwater of Iraq. The total biodiversity values of Molluscs at the Euphrates River at Al-Madinah area (Site. 1), Al-Sharsh area (Site 2), Al-Mashib area (Site 3) and Al-seba area (Site 4) were 3.1, 2.9, 2.4, 1.8, respectively, and It was noted that the highest seasonal densities of the species in the current study were recorded in the winter season, reaching 1013, 905, 762 and 639 individuals / m2 in four sites, respectively.

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Mussel production is expanding worldwide, and in Brazil the main species currently produced is the mussel Perna perna. Bucephalid trematodes have been recorded in P. perna but their larval identification is problematic. In this context, the aims of this paper were to evaluate the prevalence of bucephalids in P. perna, perform taxonomic and phylogenetic trematode studies, and analyze potential histopathological alterations in the infected host. Mussels obtained by fishers from Guanabara Bay, Rio de Janeiro, Brazil were weighed and measured, and internal organ tissues and parasites were collected. Of the 69 analyzed mussels, 24.6 % (17/69) were parasitized by bucephalid larvae. Sporocysts were located mainly in host mantle. Mussels presented sporocysts and cercaria within the connective tissue of mantle, all without associated inflammatory reactions. Parasite loads varied from less than 5 % to > 50 % of parasitized tissue. Histopathological examinations indicated that male or female gonads were not observed in 77 % (10/13) of parasitized mussels and in 4 % (2/56) identified as non-parasitized in the histology but previously classified as parasitized in the stereomicroscopic analysis. Thus, the absence of gonads may be associated with parasitism. Prosorhynchoides sp. is reported herein for the first time in mussels sampled on the coast of Rio de Janeiro, with genetic and histological data reported for the intermediate host, sporocysts and cercariae. New 28S rDNA, 18S rDNA and ITS1, 5.8S and ITS2 sequences are provided.

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Background: The order and orientation of genes encoded by animal mitogenomes are typically conserved, although there is increasing evidence of multiple rearrangements among mollusks. The mitogenome from a Brazilian brown mussel (hereafter named B1) classified as Perna perna Linnaeus, 1758 and assembled from Illumina short-length reads revealed an unusual gene order very different from other congeneric species. Previous mitogenomic analyses based on the Brazilian specimen and other Mytilidae suggested the polyphyly of the genus Perna. Methods: To confirm the proposed gene rearrangements, we sequenced a second Brazilian P. perna specimen using the "primer-walking" method and performed the assembly using as reference Perna canaliculus. This time-consuming sequencing method is highly effective when assessing gene order because it relies on sequentially-determined, overlapping fragments. We also sequenced the mitogenomes of eastern and southwestern South African P. perna lineages to analyze the existence of putative intraspecific gene order changes as the two lineages show overlapping distributions but do not exhibit a sister relationship. Results: The three P. perna mitogenomes sequenced in this study exhibit the same gene order as the reference. CREx, a software that heuristically determines rearrangement scenarios, identified numerous gene order changes between B1 and our P. perna mitogenomes, rejecting the previously proposed gene order for the species. Our results validate the monophyly of the genus Perna and indicate a misidentification of B1.

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Predators can influence prey through direct consumption as well as through non-consumptive effects (NCEs). NCEs usually occur mediated by behavioral changes in the prey upon detection of predator cues. Such changes may involve reduction of feeding with a variety of physiological consequences. We evaluated NCEs from an intertidal predatory snail (Acanthina monodon) on a dominant habitat-forming mussel species (Perumytilus purpuratus) from the southeastern Pacific coast. We tested whether A. monodon exerts negative NCEs on clearance rate, oxygen consumption rate, biodeposit production, and between-valve gap size in P. purpuratus. We found that waterborne predator cues triggered a decrease in these variables except biodeposit production. However, the organic content of the biodeposits increased in the presence of predator cues. The snail's physical contact with the mussels strengthened the negative NCEs on between-valve gap size. Since P. purpuratus is a dominant filter-feeder and foundation species in rocky intertidal habitats, predator NCEs on this species might indirectly influence ecosystem-level processes and community structure.

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BACKGROUND: The golden mussel (Limnoperna fortunei) is a highly invasive species that causes environmental and socioeconomic losses in invaded areas. Reference genomes have proven to be a valuable resource for studying the biology of invasive species. While the current golden mussel genome has been useful for identifying new genes, its high fragmentation hinders some applications. FINDINGS: In this study, we provide the first chromosome-level reference genome for the golden mussel. The genome was built using PacBio HiFi, 10X, and Hi-C sequencing data. The final assembly contains 99.4% of its total length assembled to the 15 chromosomes of the species and a scaffold N50 of 97.05 Mb. A total of 34,862 protein-coding genes were predicted, of which 84.7% were functionally annotated. A significant (6.48%) proportion of the genome was found to be in a hemizygous state. Using the new genome, we have performed a genome-wide characterization of the Doublesex and Mab-3 related transcription factor gene family, which has been proposed as a target for population control strategies in other species. CONCLUSIONS: From the applied research perspective, a higher-quality genome will support genome editing with the aim of developing biotechnology-based solutions to control invasion. From the basic research perspective, the new genome is a high-quality reference for molecular evolutionary studies of Mytilida and other Lophotrochozoa, and it may be used as a reference for future resequencing studies to assess genomic variation among different golden mussel populations, unveiling potential routes of dispersion and helping to establish better control policies.

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This study was developed to examine the effect of using charru mussel-, maçunim- and oyster-shell meals as calcium sources on the productive performance, carcass yield and bone parameters of meat quail. A total of 250 one-day-old non-sexed European quail were used. The birds were distributed into five treatments (calcium sources: calcitic lime, calcium carbonate, charru mussel shell meal, maçunim shell meal or oyster shell meal) in a completely randomized design with five replicates and ten birds per experimental unit. Feed intake, weight gain and feed conversion were evaluated from one to 35 days. At 35 days, two birds with the average weight of the plot were slaughtered per plot and used for analysis of carcass yield and bone parameters. There were no significant differences (P > 0.05) in feed intake, weight gain, feed conversion, carcass yield or tibia dry matter content, ash content and strength. The charru mussel-, maçunim- and oyster-shell meals can be used as calcium sources in the diet of European quail without affecting their productive performance, carcass yield or bone mineralization.

Objetivou-se avaliar o efeito da utilização das farinhas de conchas de sururu, maçunim e ostra como fontes de cálcio sobre o desempenho produtivo, rendimento de carcaça e parâmetros ósseos de codornas de corte. Foram utilizadas 250 codornas europeias, não sexadas, com um dia de idade. As aves foram distribuídas em delineamento inteiramente casualizado, constituído por cinco fontes de cálcio (calcário calcítico, carbonato de cálcio, farinha de conchas de sururu, farinha de conchas de maçunim e farinha de conchas de ostras), com cinco repetições e dez aves por unidade experimental. Foram avaliados o consumo de ração, ganho de peso e conversão alimentar no período de um a 35 dias. Aos 35 dias, duas aves de peso médio de cada parcela foram abatidas e utilizadas para as análises de rendimento de carcaça e parâmetros ósseos. Não foram observadas diferenças significativas (P > 0,05) para os dados de consumo de ração, ganho de peso, conversão alimentar, rendimento de carcaça, matéria seca, cinzas e resistência óssea de tíbias. As farinhas de conchas de sururu, maçunim e ostra podem ser utilizadas na alimentação de codornas europeias, como fontes de cálcio, sem afetar o desempenho produtivo, rendimento de carcaça e a mineralização óssea das aves.

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A survey of pathological conditions affecting the natural beds of the dominant bivalve species of the intertidal rocky coasts of the Southern Atlantic Ocean, was performed. Samples of the little mussel (n = 992), Brachidontes rodriguezii, which is considered a sentinel species, were collected from seven sites that present different anthropogenic activity (low anthropogenic activity, harbor, and sewage waste) along the Argentinean coast, and processed by standard histological techniques. Our results showed for the first time in a B. rodriguezii population from Mar del Plata harbor a bacterium causing cellular lysis of the spermatogenic cells (6.5% of prevalence) and in a population from Villa Gesell, a site with low anthropogenic activity, one little mussel presented cytoplasmic vacuoles in the oocytes's cytoplasm similar to a microsporidian (0.2% of prevalence). A ciliated protozoan parasitizing the cytoplasm of the epithelial digestive tubules and larval stages of two different digenean parasites, was found infecting the little mussel from both contaminated and uncontaminated sites. Sporocysts of the family Bucephalidae invaded the gonad, causing severe gonadal damage including castration, and gymnophallid metacercariae located between the mantle and shell or embedded in the mantle tissues, occupied the gonadal space. In Punta Carballido, a site located next to a sewage outfall, the highest prevalence of infection was found, for the ciliated protozoan in the digestive tubules (5.1%) and for the digenean parasites (bucephalid sporocyst 24.4%, and gymnophallid metacercariae 50%). Moreover, we found a positive correlation between shell length and overall prevalence of parasites.

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Nanoparticles such as zinc oxide nanoparticles (ZnO-NP) that are incorporated in consumer and industrial products have caused concern about their potential ecotoxicological impact when released into the environment. Bivalve mollusks are susceptible targets for nanoparticle toxicity since nanomaterials can enter the cells by endocytosis mechanisms. The aim of this study was to evaluate the influence of ZnO-NP on the redox metabolism in Limnoperna fortunei and the DNA damage after exposure to ZnO-NP. Adult bivalves were incubated with 1-, 10-, and 50-µg mL-1 ZnO-NP for 2, 4, and 24 h. Ionic Zn release, enzymatic and non-enzymatic antioxidant activity, oxidative damage, and DNA damage were evaluated. Oxidative damage to proteins and lipids were observed after 4-h exposure and returned to baseline levels after 24 h. Superoxide dismutase levels decreased after 4-h exposure and increased after 24 h. No significant alteration was observed in the catalase activity or even DNA double-strand cleavage. The dissociation of ZnO may occur after 24 h, releasing ionic zinc (Zn2+) by hydrolysis, which was confirmed by the increase in the ionic Zn concentration following 24-h exposure. In conclusion, ZnO-NP were able to induce oxidative stress in exposed golden mussels. The golden mussel can modulate its own antioxidant defenses in response to oxidative stress and seems to be able to hydrolyze the nanoparticles and consequently, release Zn2+ into the cellular compartment.

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The release of pollutants is increasing along the coast of Chile, and the use of biomarkers in biomonitoring programs is essential to assess the early biological effects of marine contamination. The Micronucleus (MN) test was carried out using hemocytes of the mussel Perumytilus purpuratus from two sites in northern-central Chile (La Pampilla and Totoralillo). Nuclear abnormalities were assessed, and high frequencies of micronucleus (10.7-14.4‰) and other abnormalities were found (51.9-76.6‰). These values tended to be higher in La Pampilla, possibly due to the large presence of pollution sources in that site. However, considerably high values were observed in both sites. P. purpuratus is a suitable bioindicator and further monitoring along the Chilean coast using this species should be developed using the MN test and/or other biomarkers to comprehend the effects of human activities on the coastal environment of Chile.

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This baseline paper shows the Indo-Pacific mussel Perna viridis (Asian green mussel) inhabiting on floating plastic substrates in the Atlantico Department, as well as rafting on marine debris found at the Via Parque Isla de Salamanca (Magdalena). Both observations are the northernmost record of the species found in the Colombian Caribbean Sea. The above finding opens a new door that suggests that larval dispersion alone may not be the only process responsible for the presence of this invasive suspension-feeder bivalve because this species needs specific vectors for its dispersal. Some organisms such Perna viridis can persist in the marine environment, but they do not necessarily have a rafting capability that allows them to move over long distances. Floating structures as well as marine debris can serve as optimal substrates in the marine environment, contributing to an increase in the problems of non-native species on sites with a high degree of susceptibility to species invasion.

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The intensive use of glyphosate in industrial agriculture may lead to freshwater contamination, encouraging studies of its toxic effect on non-target aquatic organisms. Glyphosate-based commercial formulations contain adjuvants, making them even more toxic than the active ingredient (a.i.) itself. The golden mussel Limnoperna fortunei is a freshwater invasive species which has been found to increase glyphosate dissipation in water and to accelerate eutrophication. The aim of this study is to evaluate the capability of L. fortunei to reduce the concentration of glyphosate in two commercial formulations, Roundup Max® and Glifosato Atanor®. Results were compared with the decay of the a.i. alone and in presence of mussels. Evasive response and toxicity tests were performed in a first set of trials to analyze the response of L. fortunei exposed to Roundup Max® and Glifosato Atanor®. Subsequently, we conducted a 21-day degradation experiment in 2.6-L microcosms applying the following treatments: 6 mg L-1 of technical-grade glyphosate (G), Glifosato Atanor® (A), Roundup Max® (R), 20 mussels in dechlorinated tap water (M), and the combination of mussels and herbicide either in the technical-grade (MG) or formulated form (MA and MR) (all by triplicate). Samples were collected at days 0, 1, 7, 14 and 21. No significant differences in glyphosate decay were found between treatments with mussels (MG: 2.03 ± 0.40 mg L-1; MA: 1.60 ± 0.32 mg L-1; MR: 1.81 ± 0.21 mg L-1), between glyphosate as a.i. and the commercial formulations, and between the commercial formulations, suggesting that the adjuvants did not affect the degrading potential of L. fortunei. In addition to the acceleration of glyphosate dissipation in water, there was an increase in the concentration of dissolved nutrients in water (N-NH4+ and P-PO43-) even higher than that caused by the filtering activity of the mussels, probably resulting from stress or from the degradation of glyphosate and adjuvants. We believe that a larger bioavailability of these nutrients due to glyphosate metabolization mediated by mussels would accelerate eutrophication processes in natural water bodies. The approach used here, where L. fortunei was exposed to two commercial formulations actually used in agricultural practices, sheds light on the potential impact of glyphosate decay on water bodies invaded by this species.

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In this study we test the sensitivity of three sizes of golden mussel (Limnoperna fortunei), an introduced species in Argentina, to a 96-h exposure to [Formula: see text], [Formula: see text], and [Formula: see text]. We also analysed the relative sensitivity of L. fortunei compared to other freshwater bivalve equivalent sensitivity data. The ANOVA results showed that both factors, heavy metal and size, had significant effects (p = 0.0013 and p = 0.0091, respectively) on the mortality of the golden mussel. Tukey's test showed significant differences for [Formula: see text] treatment and the smallest size class (7 mm [Formula: see text]). The relative sensitivity analysis showed that [Formula: see text] values for the smallest size class of L. fortunei exposed to [Formula: see text] and [Formula: see text] were in the low range, with values of 11.40 mg/L and 12.65 mg/L, respectively. In the case of [Formula: see text] (1.66 mg/L), its [Formula: see text] was in the medium-low range of the freshwater bivalve sensitivity distribution.

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The genus Mytilus comprises a large number of bivalve mollusk species distributed throughout the world and many of these species are considered invasive. In South America, many introductions of species of this genus have already taken place, including reports of hybridization between them. Now, the occurrence of the Mediterranean mussel Mytilus galloprovincialis is reported for the first time from the Brazilian coast. Several specimens of this mytilid were found in a shellfish growing areas in Florianópolis and Palhoça, Santa Catarina State, Brazil. Morphological analysis of the shells and molecular analysis through sequencing of the cytochrome oxidase subunit 1 (COI) confirmed the taxonomic identification. The species is known for its great invasive potential and can become a major environmental problem for seafood business and coastal communities, as it can compete and even hybridize with local species.(AU)

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The genus Mytilus comprises a large number of bivalve mollusk species distributed throughout the world and many of these species are considered invasive. In South America, many introductions of species of this genus have already taken place, including reports of hybridization between them. Now, the occurrence of the Mediterranean mussel Mytilus galloprovincialis is reported for the first time from the Brazilian coast. Several specimens of this mytilid were found in a shellfish growing areas in Florianópolis and Palhoça, Santa Catarina State, Brazil. Morphological analysis of the shells and molecular analysis through sequencing of the cytochrome oxidase subunit 1 (COI) confirmed the taxonomic identification. The species is known for its great invasive potential and can become a major environmental problem for seafood business and coastal communities, as it can compete and even hybridize with local species.

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The objective of this study was to determine the apparent and true digestibility coefficients and relative bioavailability of charru mussel, maçunim (Anomalocardia brasiliana) and oyster shells as organic calcium sources for meat quail. In the digestibility trial, 240 quail were distributed in a completely randomized experimental design with five diets (calcitic limestone, calcium carbonate and three marine calcium sources), five replicates and eight quails per experimental unit. The relative bioavailability of calcium was determined by the standard-curve and slope ratio methods in a growth trial in which 288 European quail were distributed in completely randomized experimental design. Treatments consisted of basal diet with a low calcium concentration (0.166%) that was supplemented with two levels of calcium (0.342% and 0.684%) derived from different calcium sources. The apparent and true digestibility coefficients of calcium from charru mussel-, maçunim- and oyster-shell meals for meat quail were 91.85 and 92.04%; 91.71 and 91.90%; and 89.39 and 89.63%, respectively. The relative bioavailability of calcium from charru mussel-, maçunim- and oyster-shell meals obtained using standard-curve and slope ratio methods were 133.22 and 119.18%; 140.05 and 113.69%; and 141.73 and 106.22%, respectively, allowing the use of these organic calcium sources in diet formulations for meat quail.(AU)

O objetivo deste estudo foi determinar os coeficientes de digestibilidade aparente e verdadeiro e a biodisponibilidade relativa de conchas de sururu, maçunim (Anomalocardia brasiliana) e ostra como fontes orgânicas de cálcio para codornas de corte. No ensaio de digestibilidade, 240 codornas foram distribuídas em um delineamento inteiramente casualizado constituído de cinco dietas (calcário calcítico, carbonato de cálcio e três fontes marinhas de cálcio), cinco repetições e oito aves por unidade experimental. A biodisponibilidade relativa do cálcio foi determinada pelo método da curva padrão e Slope Ratio em um ensaio de crescimento no qual 288 codornas Europeias foram distribuídas em um delineamento inteiramente casualizado. Os tratamentos consistiram em uma dieta basal, com baixa concentração de cálcio (0,166%) a qual foi suplementada com dois níveis de cálcio (0,342% e 0,684%)proveniente das diferentes fontes de cálcio. Os coeficientes de digestibilidade aparente e verdadeiro das farinhas de conchas de sururu, maçunim e ostra, para codornas de corte foram 91,85 e 92,04%; 91,71 e 91,90%; e 89,39 e 89,63%, respectivamente. A biodisponibilidade do cálcio das farinhas de conchas de sururu, de maçunim e de ostra obtidas utilizando-se os métodos da curva padrão e Slope Ratio foram133,22 e 119,18%; 140,05 e 113,69%; e 141,73 e 106,22%, respectivamente, permitindo o uso destas fontes orgânicas de cálcio na formulação de ração para codornas de corte.(AU)

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The objective of this study was to determine the apparent and true digestibility coefficients and relative bioavailability of charru mussel, maçunim (Anomalocardia brasiliana) and oyster shells as organic calcium sources for meat quail. In the digestibility trial, 240 quail were distributed in a completely randomized experimental design with five diets (calcitic limestone, calcium carbonate and three marine calcium sources), five replicates and eight quails per experimental unit. The relative bioavailability of calcium was determined by the standard-curve and slope ratio methods in a growth trial in which 288 European quail were distributed in completely randomized experimental design. Treatments consisted of basal diet with a low calcium concentration (0.166%) that was supplemented with two levels of calcium (0.342% and 0.684%) derived from different calcium sources. The apparent and true digestibility coefficients of calcium from charru mussel-, maçunim- and oyster-shell meals for meat quail were 91.85 and 92.04%; 91.71 and 91.90%; and 89.39 and 89.63%, respectively. The relative bioavailability of calcium from charru mussel-, maçunim- and oyster-shell meals obtained using standard-curve and slope ratio methods were 133.22 and 119.18%; 140.05 and 113.69%; and 141.73 and 106.22%, respectively, allowing the use of these organic calcium sources in diet formulations for meat quail.

O objetivo deste estudo foi determinar os coeficientes de digestibilidade aparente e verdadeiro e a biodisponibilidade relativa de conchas de sururu, maçunim (Anomalocardia brasiliana) e ostra como fontes orgânicas de cálcio para codornas de corte. No ensaio de digestibilidade, 240 codornas foram distribuídas em um delineamento inteiramente casualizado constituído de cinco dietas (calcário calcítico, carbonato de cálcio e três fontes marinhas de cálcio), cinco repetições e oito aves por unidade experimental. A biodisponibilidade relativa do cálcio foi determinada pelo método da curva padrão e Slope Ratio em um ensaio de crescimento no qual 288 codornas Europeias foram distribuídas em um delineamento inteiramente casualizado. Os tratamentos consistiram em uma dieta basal, com baixa concentração de cálcio (0,166%) a qual foi suplementada com dois níveis de cálcio (0,342% e 0,684%)proveniente das diferentes fontes de cálcio. Os coeficientes de digestibilidade aparente e verdadeiro das farinhas de conchas de sururu, maçunim e ostra, para codornas de corte foram 91,85 e 92,04%; 91,71 e 91,90%; e 89,39 e 89,63%, respectivamente. A biodisponibilidade do cálcio das farinhas de conchas de sururu, de maçunim e de ostra obtidas utilizando-se os métodos da curva padrão e Slope Ratio foram133,22 e 119,18%; 140,05 e 113,69%; e 141,73 e 106,22%, respectivamente, permitindo o uso destas fontes orgânicas de cálcio na formulação de ração para codornas de corte.

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Abstract The isolation of Escherichia coli from food is a major concern. Pathogenic strains of these bacteria cause diseases which range from diarrhea to hemolytic-uremic syndrome. Therefore the virulence genes in E. coli isolates from the mussel ( Mytella guyanensis) commercialized in Cachoeira, Bahia, Brazil were investigated. Samples were purchased from four vendors: two from supermarkets and two from fair outlets. They were conditioned into isothermal boxes with reusable ice and transported to the laboratory for analysis. E. coli strains were isolated in eosin methylene blue agar, preserved in brain-heart infusion medium with 15% glycerol and stored at -20 °C, after microbiological analysis. Virulence genes in the isolated strains were identified by specific primers, with Polymerase Chain Reaction. Twenty-four isolates were obtained, with a prevalence of elt gene, typical from enterotoxigenic infection, in 75% of the isolates. The stx and bfpA genes, prevalent in enterohemorragic and enteropathogenic E. coli, respectively, were not detected. The occurrence of elt virulence-related gene in the E. coli isolates of Mytella guyanensis reveals urgent improvement in food processing, including good handling practices, adequate storage and cooking before consumption, to ensure consumer's health.

Resumo O isolamento de Escherichia coli a partir de alimentos é uma grande preocupação, pois cepas patogênicas desta bactéria podem causar desde diarreia até síndrome hemolítico-urêmica. Diante do exposto, o objetivo do trabalho foi pesquisar genes de virulência em isolados de Escherichia coli provenientes do sururu Mytella guyanensis comercializado na cidade de Cachoeira, Bahia, Brasil. As amostras foram adquiridas de quatro comerciantes, sendo duas de mercados e duas em pontos de venda na feira livre da cidade de Cachoeira, acondicionadas em caixas isotérmicas com gelo reutilizável e transportadas até o laboratório para a análise. Após a análise microbiológica, as cepas de Escherichia coli foram isoladas em ágar Eosina Azul de Metileno e preservadas em caldo Brian Heart Infusion e glicerol a 15% e mantidas a - 20° C. A identificação dos genes de virulência nas cepas isoladas foi realizada utilizando primers específicos, por meio da Reação em Cadeia da Polimerase. Foram obtidos 24 isolados de Escherichia coli, destes a prevalência do gene elt , característico de Escherichia coli enterotoxigênica, foi de 75% dos isolados. Não houve a detecção dos genes stx e bfpA nos isolados, os quais são prevalentes nas cepas de Escherichia coli enterohemorrágica e Escherichia coli enteropatogênica, respectivamente. A presença do gene elt relacionado à virulência de Escherichia coli nos isolados de Mytella guyanensis revela a necessidade da melhoria no processamento, incluindo boas práticas de manipulação, armazenamento adequado e cocção previa ao consumo, visando a garantia da saúde do consumidor.

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