Journal of The World Aquaculture Society最新文献

In the United States, catfish are primarily farmed in earthen ponds, resulting in an aquatic environment influenced both by management practices and natural ecological processes. Profiling pond water microbiota can be useful for understanding what conditions may lead to microbial communities associated with production issues and could inform management practices. The aim of this study was to identify appropriate methods for bacterial community profiling of catfish pond water with nanopore sequencing of the 16S rRNA gene. To this end, two forward primers, two reverse primers, and three different polymerase chain reaction (PCR) cycle numbers were tested on a mock community consisting of aquaculture-relevant bacteria. The optimized protocol was applied to water samples obtained from three experimental catfish ponds sampled in May, June, August, and September 2020. Applying these methods to pond samples allowed for the identification of 1488 genera, primarily within four dominating phyla: Actinobacteriota, Bacteroidota, Cyanobacteria, and Firmicutes. High variation was observed between individual ponds and sampling timepoints; only 18 of the 1488 genera were found in relative abundances ≥1% in all ponds from at least one sampling point. Despite this variation, consistent results could be observed. Samples obtained from the month of September had the highest number of observed genera, and samples from June had the lowest. Overall, these data demonstrated individual ponds represent distinct microcosms composed of unique bacterial communities, although this pond effect was secondary to the influence of sampling month on pond community composition.

An acute infectious disease of northern sheatfish (Silurus soldatovi) was found in a commercial aquaculture pond in Tianjin, China. Herein, two dominant bacterial strains were isolated from naturally diseased northern sheatfish and identified as Aeromonas veronii and Vibrio cholerae. Seven healthy and seven naturally diseased fish that were collected from the pond were used for the gut microbiota analysis by high-throughput 16S rRNA gene sequencing. The α-diversity indices (ACE, Chao 1, and Shannon) did not differ significantly between diseased and healthy fish (p > 0.05), but a significant separation was observed between them when β-diversity analysis of the bacterial population was performed. The diseased fish demonstrated a significant elevation in the relative abundances of Aeromonas, Vibrio, Blautia, and Megamonas and a decrease in Cetobacterium, Bacteroides, Chryseolinea, Ralstonia, and Pseudomonas compared with healthy fish (p < 0.05). Linear discriminant analysis effect size showed that microbial marker species in the diseased fish were in the order Aeromonadales, the family Aeromonadaceae, and the genus Aeromonas. The functional profiles of the microbial community that were predicted using the PICRUSt2 indicated that the disturbance of gut microbiota caused the alteration of its functional profiles in the diseased fish.

Background: Liver transplantation (LT) is a complicated surgical procedure with high risk for massive intraoperative blood loss due to pre-existing coagulopathy, portosystemic shunts with collateral circulations, and splenomegaly. The transfusion service will direct most of their resources toward LT programs with great impact on cost. The purpose of this study was to evaluate single center transfusion strategies and to identify the risk factors associated with the intraoperative blood loss and blood transfusion.

Methods: The study includes 18 patients who underwent LT at Hospital Selayang between January 2020 and December 2020. Retrospective analysis of data included preoperative assessment of coagulopathy, intraoperative blood loss, and blood component transfusion.

Results: The mean age in the study group was 36.4 ± 12.68 years. The mean intraoperative blood loss was 4450 ± 1646 ml requiring 4.17 ± 3.3 packed red blood cell (PRBC) units, 7.56 ± 5.5 platelet units, and 9.50 ± 6.0 fresh-frozen plasma units. The independent risk factor for high blood loss (HBL) group was lower preoperative platelet count and it is statistically significant (P = 0.024). The HBL group is associated with higher usage of PRBC (P = 0.024) and platelet units (P = 0.031) and it is statistically significant. The length of stay (LOS) in intensive care unit (ICU) averaging 8.6 ± 4.95 days, and there is no significant differences comparing the HBL and LBL group (P = 0.552). The mortality <90 days for all recipients was 22.2%.

Conclusion: The preoperative platelet count for is the most important factor associated with HBL in LT procedure. The usage of PRBC and platelet units was statistically higher in the HBL group. Comparing HBL and LBL patients, there is no difference in terms of the LOS in ICU postoperatively. A larger sample size would be needed in view of relatively small sample size.

This study was conducted to investigate the effects of dietary black cumin (Nigella sativa L.) oil on growth performance, hemato-biochemical, and histopathology of cypermethrin-intoxicated Nile tilapia. After determining the LC₅₀ (96 h) value of cypermethrin, cypermethrin was added to the water at a ratio of 1:20 of this concentration, and the fish were fed for 42 days. To reduce the effects of cypermethrin, 1% black cumin oil was added to the fish feed as a potential protectant. Growth parameters, hematology, blood biochemistry, and histopathological changes of Nile tilapia were examined after the feeding period. In this study, the best growth was observed in the group fed with feed containing 1% black cumin oil, while the worst growth performance was observed in the group fed with water containing cypermethrin and without black cumin oil in the feed. As a result of the study, it was observed that black cumin oil added to the fish diet reduced the negative effects of water-borne cypermethrin on growth, hematology, blood biochemistry, and histopathological parameters of Nile tilapia.

Maintaining proper green water is important for a fish farming pond. However, it remains unclear how to translate this important rule into specific water quality characteristics to associate or even forecast changes in water color. To address this issue, we conducted a study based on daily monitoring of six grouper ponds in Fangliao Township, Pingtung, Taiwan, from March to December 2018. We investigated the relationships between changes in water color and anomalies in water temperature, salinity, and pH, as these three parameters had the most complete records. We employed a long-short-term memory model to detect water quality anomalies by computing residual values. Our findings indicate that changes in water color were associated with anomalies in these parameters, with water temperature anomalies being the best indicator for early detection. In fact, the top 5% of water temperature anomalies could predict over 40% of the water color changes. Additionally, pH anomalies occurred immediately after the color changes. This rule-to-physicochemical-parameter paradigm that we developed for grouper ponds could be applied to other aquaculture farms. We anticipate that with the help of advanced environmental surveillance models, such as the one we used, the prospect of autonomous fish farming will be realized.

In recent years, bullfrog (Lithobates catesbeianus) has become one of the most commercially important amphibians for aquaculture in China, and its annual production has grown rapidly. However, bacterial diseases caused by Citrobacter freundii infection have resulted in enormous economic losses. The present study used RNA sequencing technology to analyze the transcriptomic profile and differentially expressed genes (DEGs) in the bullfrog liver and spleen post C. freundii infection. De novo assembly resulted in the generation of 77,556 L. catesbeianus transcripts, and 49,421 of these genes were successfully annotated to the databases. Overall, 1487 DEGs were identified in the liver group, including 788 upregulated and 709 downregulated DEGs. A total of 799 DEGs, including 311 upregulated and 488 downregulated genes, were detected in the spleen groups. Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) analyses revealed significantly enriched pathways, including pathways involved in metabolism and immune responses. The processes in which the DEGs were enriched were those related to metabolic activities, including the lipid metabolism pathway, amino acid pathway, immune-related pathway, and inflammatory responses. The results of this study provide insight into the response of bullfrogs against C. freundii at the transcriptome level and reveal the mechanism of the immune response against C. freundii.

The experiment was conducted to study the effect of different dietary supplementation of alanyl-glutamine dipeptide (AGD) and/or vitamin E (VE) on the growth performance, antioxidant indexes, and the expression of glutathione peroxidase (GPx) and peroxisome proliferator-activated receptor α (PPAR_Ɑ) genes in juvenile marine medaka (Oryzias melastigma) in seawater acidification. Seven groups of juvenile marine medaka in triplicate were studied in an ecosystem. One of them was in normal seawater (pH 8.1, pH control), and the others were in seawater acidification (pH 7.7) regulated by carbon dioxide (CO₂). The juveniles were separately fed for 10 weeks using one of six different diets. The six diets were one control diet (basic feed) without supplements and the other diets with different amounts of additional AGD and/or VE. The juveniles were sampled randomly for analysis of a whole fish in week 0 and week 10. The results showed that different dietary supplementation of AGD and/or VE could considerably promote the growth performance, antioxidant indexes, and the expression of GPx and PPARα genes of juvenile marine medaka in seawater acidification. The optimal diet was D4, with additional AGD 5 g and VE 50 IU per kg of dried feed.

This study investigated the effect of replacing a portion of fish meal with unfermented and/or fermented soybean meal in juvenile coho salmon (Oncorhynchus kisutch). Four groups of juveniles (initial weight 110.31 ± 3.12 g) in triplicate were fed for 90 days on four different iso-nitrogen and iso-lipid diets. The G0 diet comprised 28% fish meal protein (control group). In the other three diets (G1, G2, and G3), 10% of the fish meal protein was replaced with unfermented and/or fermented soybean meal protein. The main results were: Compared with G0, the WGR, SGR, CF; the contents of GLU, TP, ALB, T-CHO, and T-AOC, the activities of AKP, CAT, SOD, GST, GSH-PX, O₂·-CR, OH·-CR, and GSH and the expressions of SOD, GSH-PX, GST, CAT, and Nrf2 genes of juvenile coho salmon in G3 were significantly (p < 0.05) increased, However, the FCR, HSI, the content of MDA, and the expressions of TNF-α and IL-6 genes of juvenile coho salmon in G3 were significantly (p < 0.05) decreased. There was no significant effect (p > 0.05) of diet on their survival rate (SR). In conclusion, the fermented soybean meal in the juvenile coho salmon diet can replace 10% of the fish meal protein.

A 12-week growth experiment was conducted to evaluate the suitability of Azolla cristata as a fish meal (FM) substitute in diets for Cyprinus carpio var. communis fingerlings. Six iso-nitrogenous and isocaloric (16.17 kJ/g GE) diets were formulated to contain 42% crude protein and each treatment had three replicates. The mean initial weight of the fish was 3.4 ± 0.2 g. Graded levels of A. cristata 0, 10, 20, 30, 40, and 50% in the diets were fed to the fish in triplicate groups, respectively. No significant (p > 0.05) differences in growth performance of fish-fed diets containing 10% and control (0%) inclusion levels were seen. However, further increase in Azolla meal (AM) supplementation resulted in gradual decline in growth performance of fish in terms of live weight gain, specific growth rate, feed conversion ratio, and protein efficiency ratio. All hematological parameters had a linear declining trend as the proportion of AM in diet was increased. Protein content of fish was found significantly (p < 0.05) reduced in fish-fed higher inclusion of AM. Serum biochemical parameters were also noted to reduce with increasing inclusion of AM, except for glucose, cholesterol, alanine aminotransferase (ALT), and aspartate aminotransferase (AST). On the basis of results obtained in the present study, it is recommended that 10% Azolla meal can be included in the practical diets for C. carpio var. communis fingerlings as partial replacement for fishmeal without affecting their growth, feed efficiency, and fish quality for the intensive culture of this fish species.