Piaractus Brachypomus Research Articles

Identification and Counting of Pirapitinga Piaractus brachypomus Fingerlings Fish Using Machine Learning.

Identifying and counting fish are crucial for managing stocking, harvesting, and marketing of farmed fish. Researchers have used convolutional networks for these tasks and explored various approaches to enhance network learning. Batch normalization is one technique that improves network stability and accuracy. This study aimed to evaluate machine learning for identifying and counting pirapitinga Piaractus brachypomus fry with different batch sizes. The researchers used one thousand photographic images of Pirapitinga fingerlings, labeled with bounding boxes. They trained the adapted convolutional network model with batch normalization layers added at the end of each convolution block. They set the training to one hundred and fifty epochs and tested batch sizes of 5, 10, and 20. Furthermore, they measured network performance using precision, recall, and mAP@0.5. Models with smaller batch sizes performed less effectively. The training with a batch size of 20 achieved the best performance, with a precision of 96.74%, recall of 95.48%, mAP@0.5 of 97.08%, and accuracy of 98%. This indicates that larger batch sizes improve accuracy in detecting and counting pirapitinga fry across different fish densities.

Evaluating the Presence of Interspecific Hybrids Among Piaractus mesopotamicus, Piaractus brachypomus and Colossoma macropomum in the Upper Paraná River Using Genetic Markers

ABSTRACTFish hybridization is common in aquaculture worldwide, including in Brazil, with cross‐breeding between species of the genera Piaractus and Colossoma taking the lead. However, little is known about the genetic damage caused by hybrids that escape into natural environments. In the upper Paraná River region, hybrid fishes are overproduced; therefore, the use of molecular techniques for their monitoring and identification is necessary. This study aimed to detect the presence of possible hybridization between Piaractus and Colossoma in the upper Paraná River using the molecular markers cytochrome c oxidase subunit 1 (COI) and α‐tropomyosin (TROP). Fragments from 53 fish samples were analysed, and 41 samples were considered hybrids, with 12 confirmed pure, six as Piaractus mesopotamicus (pacu) and six as Piaractus brachypomus (pirapitinga). This is the first record of P. brachypomus, which is an invasive species in this basin, while Colossoma macropomum has not been observed. Molecular markers efficiently detected hybrids in the Ivinhema and Paraná rivers. The results showed a predominance of hybrid specimens from P. mesopotamicus × P. brachypomus. Our study suggests that more restrictions on hybridization and better supervision of fish farms are needed to prevent the escape of hybrids and the consequent ecological and genetic damage to native populations. We warn of the risk of a decline in the population of P. mesopotamicus, as this species is of great importance for fishing and maintaining the ecosystem.

First record of metazoan parasites of hybrids between the genera Colossoma and Piaractus in natural environments.

The practice of hybridization is carried out globally in fish farms. Here, we present the first record of the parasitic fauna of hybrids among genus Colossoma and Piaractus in natural environments. We identified a total of 48 hybrids, nine F1 hybrids (nuclear DNA from both species present in the cross) and 38 advanced hybrids (nuclear DNA from one species), both from crosses between Piaractus brachypomus and Piaractus mesopotamicus, and one F1 "tambacu" corresponding to cross between Colossoma macropomum and Piaractus mesopotamicus. This is the first record of Anacanthorus penilabiatus, Anacanthorus toledoensis, Mymarothecium viatorum, Mymarothecium ianwhittington, Haementeria sp., Dadaytrema oxycephala, Rondonia rondoni, and Echinorhynchus gomesi parasitizing hybrids collected in a natural environment. With this, we expand knowledge about the diversity of fish and parasites in the upper Paraná River and warn about the risk that fish escapes can cause in the basin.

Microbiota diversity of three Brazilian native fishes during ice and frozen storage

This study aimed to assess the bacterial microbiota involved in the spoilage of pacu (Piaractus mesopotamics), patinga (female Piaractus mesopotamics x male Piaractus brachypomus), and tambacu (female Colossoma macropomum × male Piaractus mesopotamics) during ice and frozen storage. Changes in the microbiota of three fish species (N = 22) during storage were studied through 16S rRNA amplicon-based sequencing and correlated with volatile organic compounds (VOCs) and metabolites assessed by nuclear magnetic resonance (NMR). Storage conditions (time and temperature) affected the microbiota diversity in all fish samples. Fish microbiota comprised mainly of Pseudomonas sp., Brochothrix sp., Acinetobacter sp., Bacillus sp., Lactiplantibacillus sp., Kocuria sp., and Enterococcus sp. The relative abundance of Kocuria, P. fragi, L. plantarum, Enterococcus, and Acinetobacter was positively correlated with the metabolic pathways of ether lipid metabolism while B. thermosphacta and P. fragi were correlated with metabolic pathways involved in amino acid metabolism. P. fragi was the most prevalent spoilage bacteria in both storage conditions (ice and frozen), followed by B. thermosphacta. Moreover, the relative abundance of identified Bacillus strains in fish samples stored in ice was positively correlated with the production of VOCs (1-hexanol, nonanal, octenol, and 2-ethyl-1-hexanol) associated with off-flavors. 1H NMR analysis confirmed that amino acids, acetic acid, and ATP degradation products increase over (ice) storage, and therefore considered chemical spoilage index of fish fillets.

Physio-metabolic alterations in Labeo rohita (Hamilton, 1822) and native predator Chitala chitala (Hamilton, 1822) in presence of an invasive species Piractus brachypomus (G. Cuvier, 1818).

A 60days study was conducted to evaluate the physiological response of indigenous species Labeo rohita (LR) and indigenous predator Chitala chitala (CC) in presence of an invasive species Piaractus brachypomus (PB). Two treatment groups as LR + PB (T1) and LR + PB + CC (T2) with individual control groups as T0LR, T0PB and T0CC were designed in triplicates. Fingerlings of LR, PB and CC were randomly distributed into 15 circular tanks with a stocking ratio of 1:1 and 1:1:0.3 in T1 and T2 group, respectively and 10 nos. each of LR, PB and CC in respective control groups. At first 15min of the experiment, cortisol level was found significantly (P < 0.05) higher in all three experimental fishes in T1 and T2 groups. With the experimental duration, the level of stress hormone (cortisol), oxidative stress enzymes (superoxide dismutase, catalase, and glutathione peroxidase), tissue metabolic enzymes (lactate dehydrogenase and malate dehydrogenase), serum metabolic enzymes (transaminase enzymes) and blood glucose level were significantly (P < 0.05) increased in T1 and T2 groups for LR and CC whereas, no variation (P > 0.05) were observed for PB in both T1 and T2 groups. The total antioxidant capacity (TAC), liver glycogen, total protein, albumin and globulin were found to be significantly (P < 0.05) decreased in LR in the presence of PB and CC. The present study provides a preliminary insight into the biological interaction between native and invasive species and their physiological responses in the presence of native predator with higher trophic index. Thus, the results of the study suggest the superior traits of invasive P. brachypomus try to dominate the other two native species by negatively influencing the native fauna even with a higher trophic index (C. chitala).

Molecular identification of Mymarothecium viatorum and Anacanthorus penilabiatus in extensive native fish farming systems of the Peruvian Amazon

Piaractus brachypomus (Pacú) is the main native fish species cultivated in Peru and holds great potential for growth in aquaculture from the Peruvian Amazon. Between October 2021 and January 2022 in two fish producing farms in the Amazon region of San Martín in Peru, P. brachypomus individuals were examined for parasite evaluation. A total of 6366 monogeneans were isolated from the gills of 30 fish, revealing a prevalence of 100%, with an abundance and mean intensity of 212 parasites per fish. Monogeneans were morphologically identified as Mymarothecium viatorum and Anacanthorus penilabiatus. The genetic divergence in the 28S rDNA gene found among A. penilabiatus sequences was 0.1% and among Anacanthorus spp. it ranged from 0.9% to 7.5%. The genetic divergence found among the M. viatorum sequences was 0.3%. These finding represents the first molecular data of M. viatorum and A. penilabiatus in Peru using the 28S rDNA gene of these monogeneans. The new sequences obtained will contribute to future studies on the phylogenetic relationships among dactylogyrids. However, further research with a broader range of host-parasite samples and additional genetic markers is needed to clarify these relationships and provide stronger support for the phylogenetic positions.

Community Structure Characteristics and Changes in Fish Species at Poyang Lake after the Yangtze River Fishing Ban

To understand the fish community structure characteristics and changes in Poyang Lake after the Yangtze River fishing ban in 2021, seven sampling stations were established, namely in Hukou, Lushan, Duchang, Yongxiu, Nanjishan, Ruihong, and Poyang, for fishery resource surveys between 2020 and 2021. The results showed that 93 fish species were identified, belonging to 11 orders, 20 families, and 61 genera, which was an increase of 4.5% from before the fishing ban. Of these, 52 Cyprinidae species were identified, comprising the highest proportion (55.91%). Four invasive alien species (hybrid sturgeon, Cirrhina mrigala, Piaractus brachypomus, and Mugil cephalus) were identified, and the number of alien species in Poyang Lake was higher than before the fishing ban. Carnivorous and mid-lower-level fish showed a significant increase, accounting for 47.31% and 38.71% of the total species, respectively. Compared with the Yangtze River before the fishing ban, the body length and body weight of the main economic fish in Poyang Lake increased by 6.10–61.26% and by 15.14–291.57%, respectively. In terms of age structure, the proportion of major economically important fish aged 1 or 2 years decreased significantly, while the proportion of older fish increased substantially. There was little difference in the diversity of fish communities at different stations in Poyang Lake. In terms of biodiversity, the Shannon–Wiener index ranged from 2.158 to 2.909, with Poyang having the highest value and Nanjishan the lowest. Margalef’s index ranged from 4.265 to 6.459, with Lushan having the highest value and Nanjishan the lowest. Pielou’s index ranged from 0.617 to 0.822, with Duchang having the highest value and Nanjishan the lowest. Hence, the Yangtze river fishing ban has played an important and positive role in the restoration of fishery resources in Poyang Lake. However, long-term tracking and monitoring are needed to provide information to comprehensively evaluate the ecological impact of the Poyang Lake fishing ban.

Effects of peptides and probiotics supplementation via diet on blood parameters and growth performance of Piaractus brachypomus during the growth-out phase.

There is no evidence of peptides-probiotics symbiosis as supplements in aquafeeds. To evaluate the effect of peptides and probiotics supplementation via diet on blood parameters and growth performance of juvenile Piaractus brachypomus, an Amazonian fish, during the growth-out phase. 120 juvenile P. brachypomus (242.77 g) were placed into twelve 200-l tanks (10 fish/tank), housed in an indoor open system with constant water renovation (flow rate:1.50 l/minute). The experiment used a completely randomized design with a 4 × 5 factorial arrangement [4 doses of supplementation (CD: commercial diet; PepD: CD+1.50% of peptides per CD weight; ProD: CD+40.00 ml of activated probiotics per kg of diet (Lactobacillus spp., Rhodopseudomonas spp., Saccharomycetes spp.); PepProD: CD+Pep+Pro); 5 sampling times (zero, second, fourth, sixth, and eighth week); n = 3]. Fish were fed twice a day at a feeding rate of 1% of body weight. At each sampling time, blood was collected and fish were measured for growth performance analysis. Data were analyzed by using two-way ANOVA and Tukey's test (p < 0.05). The values of hematocrit (18.31%), leukocytes (1,216.67 mm3), neutrophils (81.27%), lymphocytes (18.73%), albumin (1.08 g/dl), relative growth rate (1.002%/day), and the Fulton allometric condition factor (2.03) remained constant throughout the experiment (p > 0.05). Plasma glucose decreased for all fish in the second week (59.56 mg/dl); then, that level increased in fish fed with the CD (89.00 mg/dl), while fish fed with PepD, ProD, and PepProD showed constant values (57.22 mg/dl). The plasma protein levels were constant in fish fed with the PepD and PepProD, (p > 0.05), while fish fed with the CD and ProD showed non-constant and higher values. At the end of the trial, fish fed with the PepProD showed the highest weight gain and the lowest feed conversion rate (39.66 g; 0.97). It is possible to maintain the stability of plasma glucose and plasma protein by supplementing diets with peptides, but the peptides-probiotics symbiosis administrated via diet contributes to maintaining the stability of plasma glucose and plasma protein and to improve the growth performance of juvenile P. brachypomus during the growth-out phase.

Qualitative detection of formaldehyde in challani fish obtained from selected fish markets of Nagaon, Assam, India

Preservatives are used to increase the shelf life of any product for a very long time, yet they are extremely detrimental to human health when used in food. The use of preservatives like formaldehyde by fishermen and fish merchants for prolonged preservation of fish during sales and transportation has recently become problematic and threat to human health. Therefore, the goal of the current investigation was to determine the presence of formaldehyde in the fish sold at fish markets in Nagaon, Assam. The present investigation indicates the contamination of fish with formaldehyde in the local fish markets of Nagaon district. The fish that show the presence of formaldehyde are imported (challani) and out of the whole fish sample collection (challani/imported), Labeo rohita, Catla catla indicates the highest positive result, with 35.96% and 48.44% respectively from the 114 Labeo rohita to 64 Catla catla samples. Additionally, the results for Ompok pabda, Pangasius pangasius, Hilsa ilisha, and Piaractus brachypomus are all positive, with Hilsa ilisha showing a positive result of 100% from their whole sample collection. However, the local fish like Labeo gonius, Cirrhinus reba, Ctenopharyngodon idella, Cirrhinus mrigala, and Hypophthalmicthys nobilis fish species have shown 100% negative results for formalin detection, indicating that their samples are formalin-free. Since formaldehyde is harmful to human health, better methods and techniques should be adopted for the preservation of fish for commerce and storage. Strict regulations should be put in place to limit the use of these hazardous chemical substances.

Hematological, biochemical and oxidative responses induced by thermal shock in juvenile Tambaqui (Colossoma macropomum) and its hybrid Tambatinga (Colossoma macropomum x Piaractus brachypomus).

The effects of thermal shock on hematological, biochemical and antioxidant responses were evaluated in liver tissue of juvenile tambaqui (Colossoma macropomum) and tambatinga (♀ C. macropomum × ♂ Piaractus brachypomus). Forty juveniles of tambaqui and 40 juveniles of tambatinga, of the same age and with an initial weight of 23.3 ± 6.7g, were randomly distributed in eight 28L circular tanks. A tank (n = 10 fish) of tambaqui and a tank (n = 10 fish) of tambatinga were then used to obtain basal data. The other animals were subjected to thermal shock with sudden temperature reduction from 28 to 18 ºC. Blood and tissue were then collected after 1, 6 and 24h from the onset of thermal shock. No mortality was observed during the experimental period. Thermal shock increased triglyceride levels after 24h of stress for tambaqui and reduced values for tambatinga. There was an effect on plasma glucose only for fish group (P < 0.0001) and collection time (P < 0.0001) with a peak observed for the hybrid after 6h. The interaction of factors for SOD indicated greater activity for tambatinga at the 6h collection and lower at basal and 1h collections. There was an interaction for CAT (P = 0.0020) with less activity for tambatinga at 1h. However, thermal shock and hybridization did not influence GST and TBARS levels in liver tissue. Therefore, the results suggest that the hybrid, tambatinga, is more efficient at promoting adjustments of biochemical responses and antioxidant enzymes during thermal shock.

New record of monogenean parasite Mymarothecium viatorum (Monogenea; Dactylogyridae) in red-bellied pacu (Piaractus brachypomus) in Indonesia

Red-bellied pacu (Piaractus brachypomus) is a popular exotic fish cultured globally for ornamental and human consumption purposes. In Indonesia, this fish is mainly cultured in Java, including to supply seed to other regions for the ornamental fish trade or aquaculture. Although this exotic fish in widely cultured, information on parasitic infections is negligible. Red-bellied pacus were purchased from a fish farmer and examined for monogenean parasite infection. Monogenean parasites were identified based on morphological and molecular characteristics. Histopathological examinations were performed on gills from heavily infected fish. DNA was extracted from an individual monogenean; 18S rRNA PCR product was sequenced and a phylogenetic tree constructed. Morphological and molecular traits identified the monogenean as Mymarothecium viatorum, the first report of the neotropical M. viatorum in this region. The parasite was most likely introduced to Indonesia through the importation of ornamental fish. This parasite had a prevalence of 79% and a mean intensity of 7.1. There was no significant correlation between the parasite abundance and the condition factor of the fish. M. viatorum was more abundant on smaller fish than on larger fish. Gill histopathology showed oedema, severe haemorrhage, and infiltration of inflammatory cells. The occurrence of these parasites could pose a serious threat to the development of red-bellied pacu culture.

Two new species of Anacanthorus (Monogenoidea, Dactylogyridae) parasitizing serrasalmid fish in Brazil.

During studies on fish parasites, two new species of Anacanthorus were found parasitizing serrasalmid fishes, Anacanthorus simpliciphallus sp. n. from the hybrid Piaractus mesopotamicus x Piaractus brachypomus and Anacanthorus brandtii sp. n. from Serrasalmus brandtii. Anacanthorus simpliciphallus sp. n. resembles Anacanthorus reginae in the morphology of the male copulatory organ (MCO) and accessory piece but differs from A. reginae in terms of the smaller size of the accessory piece, which corresponds approximately half the size of the MCO and by the presence of a conspicuous metraterm, with a membranous terminal region. Anacanthorus brandtii sp. n. differs from Anacanthorus scapanus by the expansion of the accessory piece, from Anacanthorus jegui by the ratio MCO (male copulatory organ) /AP (accessory piece) and by the expansion of hook shank, from Anacanthorus sciponophallus and A. reginae by the ratio MCO/AP. Anacanthorus brandtii sp. n. can be distinguished from A. reginae and A. simpliciphallus sp.n. by the size of hooks which is similar in A. reginae and A. simpliciphallus sp. n. and dissimilar in A. brandtii sp. n. The two new species also differ from each other by the expansion of shank.

TRATAMENTOS NATURAIS DE LESÕES EM REPRODUTORES DE PEIXES

The aim of this research was to test the use of natural operating as prophylaxis for the treatment of injuries and diseases during fish reproduction at aquaculture stations as an alternative treatment to allopathic medicines. The main objective was to analyze the mastic bark (Schinus terebenthifolius), garlic bark (Allium sativum), and sodium chloride (NaCl) regarding their antimicrobial properties for prophylactic use. The broodstocks of the species pirapitinga Piaractus brachypomus were kept confined in water tanks with a capacity of 1000 L, with a continuous water flow for oxygenation and renewal. The stock density was 3 fish/m³, due to the fish being the breeding season why it becomes territorial. A confrontation between males occurred, causing the loss of scales in one of the specimen, mainly above the lateral line. The treatment of this injured fish lasted for 21 days, daily in the morning and afternoon; it was bathed in a 30g/L salt solution for 30 seconds, then the mastic and garlic extract were applied directly to the injury. For the mastic extract 50 mL of the concentrate was used without dilution and for the garlic extract 40 mL was diluted in 60 mL of water

A description of the culture of tambatinga (Colossoma macropomum x Piaractus brachypomus) in a South American tropical region and the interaction of farm size with value chains

Understanding the economic efficiency of pond-based fish culture in tropical developing countries is essential for defining development programs. This study was designed to describe the aquaculture of tambatinga in various farm sizes that is being performed in a region close to the equator in Brazil called the midnorth. The major focus was on the economic performance and the relationship between different farm sizes and downstream value chains. We also describe the attractiveness of investments in small farms. A purposive sample of commercial tambatinga farms was taken. Sixteen farms were selected which encompassed a representative sample of progressively increasing production areas, ranging from 0.1 ha to 220 ha. Complete enterprise budgets were developed for each farm based on standard budgeting techniques, and indicators of financial feasibility were computed. The farming of tambatinga in the midnorth is performed in semi-intensive levee or watershed pond systems in farms of various levels of complexity and different production strategies. All farms perform a monophase cycle, stock small fingerlings (3 to 6 g) and feed fish with a commercial diet. Yield, net income, economic profit, net present value, internal rate of return and benefit/cost ratio were found to decrease as farm size increased. Payback period and break-even point increased as farm size increased. Small aquaculture farms (≤ 1.5 ha) had a vertical business structure and presented a more effective economic performance. They are also attractive as family investments. This model of enterprise can boost rural economies and reduce poverty in developing countries. Large farms (≥ 17 ha) were not economically feasible because they do not operate in the market and sell their production at lower prices. Increasing farm size should go hand in hand with improvements in technology to be feasible.

Molecular Characterization of Neurogranin (NRGN) Gene from Red‑Bellied Pacu (Piaractus brachypomus)

Neurogranin (NRGN) is a small brain protein expressed in various telencephalic areas and plays an essential role in synaptic plasticity by regulating the availability of calmodulin (CaM). The study aims to characterize the neurogranin gene in Colombian native fish, red-bellied pacu, Piaractus brachypomus, its basal tissue expression and differential expression in brain injury and sublethal toxicity by organophosphates. NRGN gene contains an open reading frame of 183 nucleotides encoding for 60 amino acids. Bioinformatics analysis showed an IQ motif necessary in the interaction with CaM. NRGN mRNA was detected in tissues with higher expression in brain, gills, and head kidney. In brain regions, NRGN showed high expression in the telencephalon (TE) and olfactory bulb (OB). In the sublethal toxicity experiment, NRGN mRNA was upregulated in individuals under organophosphate exposure in the OB and optic chiasm (OC). In brain injury experiment, NRGN showed upregulation at 14 days in OC and at 24 h and 7 days in TE. These findings demonstrate the differential expression of NRGN under different experimental conditions which make it a candidate for a biomarker in the brain of P. brachypomus.

Pathogenic Aeromonas spp in Amazonian fish: Virulence genes and susceptibility in Piaractus brachypomus, the main native aquaculture species in Peru

The aim of this study was to isolate and identify Aeromonas species, characterize their virulence genes factors, and to evaluate their lethality in Piaractus brachypomus. Presumptive Aeromonas (n = 34) were selected from 44 bacteria retrieved from diseased Amazonian fish. Nineteen isolates were chosen based on fish species, group, the location where were isolated, and colony morphology. Isolates were biochemically and molecularly identified as Aeromonas hydrophila, A. dhakensis, A. veronii, A. jandaei, and A. caviae using API 20E, API 20NE and the analysis of 16 S rRNA and gyrB genes, respectively. Eight virulences genes (aer, altA, act, hly, ser, lip, fla ahyB) were found in one A. dhakensis and two A. hydrophila isolates. A. veronii, A. jandaei, and another two A. hydrophila isolates harbored four, two and three virulence genes, respectively. All A. caviae were fla +, ahyB + and lip +, except two isolates that also presented ser and altA. P. brachypomus (9 ± 1 cm), infected intraperitoneally (4 ×106, 4 ×107, and 4 ×108 CFU/fish), showed susceptibility to all Aeromonas species, each harboring a different virulence genes profile. Both A. hydrophila and A. dhakensis caused > 80% mortality at the lowest evaluated concentration (∼106 CFU/fish). A. veronii and A. jandaei isolates produced 20% and 70% mortality, respectively, using ∼107 CFU/fish, but with lower intensity compared to A. hydrophila and A. dhakensis. At the highest concentration (∼108 CFU/fish), A. veronii caused 70% mortality, while A. caviae isolates caused mortality ranging from 50% to 80%. Remarkably, A. jandei resulted in 100% mortality at this level, similar to A. hydrophila and A. dhakensis. This report confirms the variety of Aeromonas species infecting farmed native Amazonian fish. The study also suggests that virulence genes evaluated in Aeromonas species may not always be an indicator of virulence. Moreover, P. brachypomus, an economically important aquaculture fish species could be susceptible not only to the high mentioned A. hydrophila but also to other less observed species such as A. dhakensis, A. veronii, A. jandaei, and A. caviae, bacteria that should be taken into account in health surveillance for the implementation of aquaculture disease prevention strategies.

Physiological responses to long fasting followed by refeeding in juveniles of pirapitinga, Piaractus brachypomus

ABSTRACT For many fish species, prolonged fasting is part of their life cycle, as there are seasonal fluctuations in the quantity and quality of food available in their natural habitat. These animals use endogenous reserves during periods of food scarcity and recover when resources become available again. We evaluated the effect of a prolonged fasting period on indicators of body reserve use, growth performance and intestinal integrity of the Amazonian serrasalmid Piaractus brachypomus. We distributed 66 juveniles (68.6 ± 2.2 g) in 11 tanks. The treatment consisted of 30 days fasting followed by 45 days refeeding and the control of 75 days normal feeding with 5 replicates (one tank with six fish). The six individuals in the 11th tank were used for baseline measurements. Blood parameters, muscle lipid concentration, hepatosomatic and mesenteric fat indices, somatic growth parameters and intestinal villi morphology were measured every 15 days. Glucose, triglycerides, cholesterol, total protein, the mesenteric fat and hepatosomatic indices, weight gain, specific growth rate, condition factor and total biomass decreased significantly during fasting compared to the control, but all except body condition recovered during refeeding. The length and perimeter of the intestinal villi was significantly lower during fasting compared to the control. The feeding protocol allowed P. brachypomus to mobilize part of their body reserves during fasting, however, in general, refeeding was sufficient to restore their body needs and growth performance compatible with that of continuously fed animals.

Production Optimization and Characterization of Antioxidant Protein Hydrolysate From Piaractus brachypomus Fish Meat By Probiotic Bacillus Strain Isolated From Chicken Gizzard

Production Optimization and Characterization of Antioxidant Protein Hydrolysate From Piaractus brachypomus Fish Meat By Probiotic Bacillus Strain Isolated From Chicken Gizzard

Oxidative stress caused by a commercial presentation of glyphosate in two indigenous fish species of importance in Colombia

The use of glyphosate to eradicate poppy (Papaver somniferum) and coca (Erythroxylon coca) plants is of great concern in Colombia due to potential effects on the environment. Juveniles of white cachama (n=36) (Piaractus brachypomus) (22.7 ± 2.9 g) and yamú (Brycon amazonicus) (n=36) (11.7 ± 1.1 g) were exposed for 96 h to three glyphosate concentrations (0, 5 and 15 ppm, v/v, as Roundup®). Enzymes linked to oxidative stress in liver and gills were measured after the exposure. The main oxidative stress changes happened in the gills of glyphosate-exposed cachama and liver of both species. There was a significant decrease in reduced glutathione (GSH) and glutathione-s-transferase (GST) activity of both species. Catalase activity was significantly reduced in livers of exposed cachama. Lipid peroxidation had a significant increase in glyphosate-exposed cachama (liver and gills) and yamú (liver). The biochemical changes found in both species and both organs indicate the oxidative effects of glyphosate as Roundup® despite the asymptomatic and non-lethal exposures.

Distribution and diversity of fishes and lampreys in Transylvania (Romania): a complete survey and suggestions for new protected areas.

Freshwater fishes are in a serious state of decline across the world, making them one of the most threatened groups of vertebrates. The Danube River catchment area in Europe holds the richest freshwater fish community, but our knowledge of the current distribution of these species is limited. Transylvania, the largest region of Romania, is one of the important tributaries of the Danube, from where 77 fish and two lamprey species were recorded until now. Despite this large diversity of freshwater fishes, there is a lack of systematic survey of the fish fauna in this region for the past 50 years. In this study, we present data on the occurrence and distribution of fishes and lampreys collected in Transylvania from 2007 to 2022. This data covers 43% of Romania's surface and includes all major rivers from Transylvania. 65 species of fish and three species of lampreys are recorded, and an additional nine fish species are also reported based on information from competent people. Of the 77 fish and lamprey species recorded 19 (24.7%) are non-native, although their relative abundance was low (5.1%) compared to other similar regions in Europe. The first records of Eudontomyzonmariae, Neogobiusmelanostomus, Piaractusbrachypomus, Pygocentrusnattereri, and Salvelinusalpinus in Transylvanian rivers are presented, as well as the first record of Cobitiselongata outside the Nera River basin (from the Caraș River) and the detection of three new populations of the vulnerable Umbrakrameri. Data on changes in distribution that have occurred since the last comprehensive survey 50 years ago are also provided and the importance of our results in conservation planning are discussed, including the designation of new protected areas for freshwater bodies and the compilation of the Romanian Red List of fishes.