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Selective breeding could improve the juvenile quality of Chinese mitten crab Eriocheir sinensis
Get PDFChinese mitten crab Eriocheir sinensis is an important aquaculture species in China, and a selective breeding program has been operated for the economic traits of growth and different maturity time of this species since 2011. This study was aimed to evaluate the juvenile quality of two selected E. sinensis lines (i.e. early-maturing strain: EM, late-maturing strain: LM), pond-reared juveniles without selection (PR) and wild-caught juveniles (WC). The results showed that: (1) Significant growth difference were only observed in females that the SGR of EM juveniles and the survivor of WC juveniles were both significantly higher than the PR, and the intermolt period of WC was significantly lower than the PR. Although EM juveniles had relatively shorter intermolt period and higher WGR than the LM, they both exhibited better growth performance than the PR, in terms of higher WGR and SGR. (2) Hepatopancreatic AKP activities of PR juveniles were significantly lower than other three populations for both genders, and hepatopancreatic MDA content was significantly higher in the WC juveniles. Moreover, hemolymphatic levels of ACP and T-AOC of both EM and LM juveniles were significantly higher than other two populations. (3) The injection of Aeromonas hydrophilia resulted in the highest and lowest cumulative mortalities to the WC and PR juveniles respectively, mortalities of EM and LM juveniles were similar and located between WC and PR juveniles. In conclusion, juvenile quality of EM and LM strains obtained certain promotion after three generations of selection for growth and different maturity time
Preliminary Study for the Evaluation of the Hematological Blood Parameters of Seabream with Machine Learning Classification Methods
Get PDFFish production becomes more and more critical in the world. The most important parameters in production are health, safety, and economy. As a requirement of the technological age, computer-based applications are utilized in providing all these, for example, artificial neural networks, machine learning, deep learning, ...etc. In this study, Random Forest (RF), k-Nearest Neighborhood (k-NN), Naive Bayes (NB), Logistic Regression (LR), Decision Tree (DT) and Support Vector Machines (SVM), were used by Python 3.6 programming language for the evaluating the effects of mannanoligosaccharides with hematological blood parameters. Two diets (0%, and 2‰) prepared for the fish. At the end of 12 months trial period, there were no significant changes in the hematological blood parameters without hematocrit (Hct). Hct decreased significantly in fish fed with 2‰ mannanoligosaccharides. RF, LR, DT, and SVM have the same highest accuracy level with 80 %. However, k-NN and NB have the same lowest accuracy level with 60 %. According to these results, RF, LR, DT, and SVM models can be used as a classification tool between groups. Thus, it might be that the sensitivity level of correctly chosen machine learning applications is higher than statistical analysis
Research Progress on the Polymeric Immunoglobulin Receptor (pIgR) in Fish
Get PDFThere are a large number of pathogens in the water where fish live, and the mucosal-associated lymphoid tissues (MALTs), such as skin, gill and intestine, are the first contact parts when pathogens infect fish. The secreted mucus of these tissues constitutes the first barrier for fish against the invasion of external pathogens. Mucosal immunity can identify and neutralize pathogens and induces immunocytes to devour pathogens and the like. As a key factor in the mucosal immune system, the polymeric immunoglobulin receptor (pIgR) is capable of mediating the transport and secretion of polymeric immunoglobulins towards mucus. The effective secretion of the pIgR is necessary for polymeric immunoglobulins (pIg) to exert mucosal defence and plays a significant role in fish immunity. With the deepening of research into fish immunoglobulins, the pIgR has become a research hotspot. The molecular structure, genetic structure and expression pattern of the pIgR and the important role it plays in mucosal immunity were summarized in this study, which contributed to a deeper understanding of fish mucosal immunity and laid a foundation for further exploration of the action mechanism and functions of the pIgR in fish
Effects of Vinegars on the Growth Performance of Black Tiger Post Larvae Shrimp, Penaeus monodon
Get PDFThis study aimed to investigate the effect of acidifying the diet of black tiger shrimp Penaeus monodon on its growth and feed efficiency by supplementing coconut sap vinegar CSV) or sugar cane vinegar (SCV) or their 1:1 combination. Three hundred and sixty post larva shrimps (average initial weight of 0.01g) were randomly distributed into 12 50-L plastic containers. Four experimental diets, namely, control diet, 2% CSV, 2% SCV and 2% CSV+SCV were fed to groups of shrimps. After 90 days, all shrimps fed with diets containing vinegar exhibited significantly higher final average body weight (FABW), weight gain (WG), feed intake, specific growth rate (SGR), and better feed conversion ratio (FCR) than those fed the control diet. Attractability tests showed that the CSV and CSV+SCV diets attracted significantly the highest percentage of shrimps after 10 min of feed placement. Survival rate was not significantly different among the treatments. In conclusion, the results demonstrated that the vinegars tested could be used as growth enhancers in shrimp and that the combination of coconut sap and sugar cane vinegars supplemented to the diet resulted in the best growth and feed efficiency as well as attracted the most percentage of shrimps
Aeromonas veronii, a potential pathogen of enteritis in snakehead fish Ophiocephalus argus
Get PDFEnteritis is known as a major disease in snakehead fish Ophiocephalus argus aquaculture and has resulted in large economic losses. Yet only scarce information is available on Aeromonas veronii as a causal agent for enteritis in O. argus. In this study, a virulent strain, temporarily named HY2, was isolated from diseased snakehead fish suffering from enteritis, and was identified as A. veronii through molecular and phenotypic methods. In addition, the HY2 isolate showed an LD50 value of 2.8×105 CFU mL-1, and was highly sensitive to aminoglycosides, macrolides, polypeptides, quinolones, sulfonamides and tetracyclines antibiotics. To the best of our knowledge, this is the first report of A. veronii as a potential pathogen of enteritis in snakehead fish
