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Empirical study on the psychological mechanism of consumers in the context of live streaming seafood sales: evidence from China
No full textThe advent of the 5G era signifies China's official entry into the digital economy. This technological shift has attracted countless merchants to the market via e-commerce platforms, seeking to capitalize on new opportunities. Concurrently, it offers a novel avenue for expanding seafood sales channels in China. The interactive and intuitive nature of e-commerce live streaming has subtly but significantly influenced and shaped consumers' purchasing behaviors. In light of this, this study, based on 330 valid survey responses and grounded in the theories of perceived value and consumer trust, explores the psychological mechanisms affecting consumers in the context of e-commerce live streaming for aquatic products. The findings reveal that: (1) Consumer trust positively impacts purchase intention in the context of live-streamed seafood e-commerce. (2) Perceived entertainment value positively influences consumer purchase intention. (3) Perceived utilitarian value also positively influences consumer purchase intention. This paper contributes theoretically by broadening the application of perceived value theory and enhancing the understanding of consumer behavior concerning seafood. Additionally, it may offer practical insights into the expansion of seafood sales channels and market scale in other countries and regions
GLUT2 gene from <em>Penaeus monodon</em>: Molecular characterization, expression and association with tolerance to low salinity stress
No full textThe full-length cDNA sequence of Penaeus monodon glucose transporter-2 (PmGLUT2) was cloned in this study using the RACE method. Quantitative real-time PCR was used to analyze the differential expression of PmGLUT2 during the development of P. monodon larvae in different tissues and under low salinity stress. The PmGLUT2 cDNA exhibited a total length of 2018 base pairs, with 94 base pairs located in the 5' untranslated region (UTR) and 352 base pairs in the 3' UTR. Additionally, the sequence contained 29 base poly (A) tails and 1572 base pairs within the open reading frame (ORF), capable of encoding 523 amino acids. Through a comparative analysis of the amino acid sequences of PmGLUT2 and LvGLUT2, it was determined that PmGLUT2 had 94.77% homology with Tret1 gene of Litopenaeus vannamei, and 60.54% homology with GLUT2 gene of L. vannamei. The results indicated that there was a fluctuation in PmGLUT2 expression levels from zygote to postlarva development, with initial reduction followed by an increase, although the difference was not statistically significant. According to the molting analysis, the highest expression level of PmGLUT2 was observed in the hepatopancreas during the premolt period, while the gill and gut exhibited peak expression levels during the intermolt period. PmGLUT2 was found to be most abundant in lymph tissue, followed by gill tissue, and least abundant in ootheca, according to the tissue expression analyses. Following 96 hours of acute salt stress, there was a notable inhibition in the expression of PmGLUT2 in the hepatopancreas and gills. Additionally, the expression level in the gills at 96 hours was significantly lower compared to the baseline level at 0 hours
Early weaning protocols for the brackishwater nursery culture of the tropical anguillid eel <em>Anguilla marmorata</em> (Quoy & Gaimard, 1984)
No full textFeeding trials with Anguilla marmorata during the nursery culture were conducted to establish optimized protocols for transitioning from live to formulated diets. This study evaluated different weaning schemes over three phases of the nursery culture: from live feed (Artemia) to raw fish meat-based mash (FMT), from FMT to dry fish meal-based mash (FML), and from FML to dry formulated crumble diet. Specific growth rate (SGR), percent weight gain (%WG) and survival of A. marmorata elvers were assessed across treatments. The optimized weaning scheme for transitioning A. marmorata glass eel feeding from Artemia to FMT requires a 6.25% reduction of live feed daily for 16 days, resulting in the highest growth performance (SGR=4.49, %WG=109.25%) and survival (98.37%). Dietary transition from FMT to FML feeding, a 5% daily reduction of FMT with FML, over 20 days was found optimal. This treatment yielded superior growth performance with an SGR of 1.59, %WG of 68.80%, and survival of 62.00% (pA. marmorata during the nursery stage from live feed to dry-formulated diets within a 40-day period, enhancing the growth and survival of A. marmorata cultured in the brackish water nursery system. Published on November 08, 2024 CD
Studies on the resistance of three pathogens isolated from wild <em>Charybdis japonica</em> and their pathogenicity in <em>Portunus trituberculatus</em>
No full textThe coagulation property of hemolymph is one of the characteristic indicators of the immune function of crustaceans. This article focuses on the abnormal phenomenon of wild Charybdis japonica, where the hemolymph cannot coagulate in the Qinhuangdao Sea area. The pathogens were isolated and purified, and three dominant strains, N1, N2, and Q1, were obtained. These strains were identified as Vibrio natriegens, V. fortis, and Metschnikowia bicuspidata through morphological observation, physiological and biochemical experiments, and 16S rDNA or ITS sequence analysis. Subsequently, drug sensitivity and probiotic antagonism analyses were performed. Considering the potential for cross-species transmission of crustacean pathogens, the isolated pathogens may bring potential hazards to Portunus trituberculus, an important aquaculture economic species in China. Therefore, artificial infection and histopathological analysis were conducted on P. trituberculatus. The results of drug sensitivity and antagonism assays revealed that stain V. natriegens exhibited susceptibilities towards antibiotics such as streptomycin and norfloxacin, but 10 probiotics had no antagonistic effect on it; strain V. fortis exhibited susceptibilities to antibiotics such as tetracycline and chloramphenicol, moreover, strain V. fortis showed inhibitory effects on Bacillus velezensis and B. amyloliquefaciens. Strain M. bicuspidata exhibited drug susceptibility towards polymyxin B and showed inhibitory effects on B. toyonensis, B. velezensis, and B. amyloliquefaciens. The results of artificial infection tests using V. natriegens, V. fortis, and M. bicuspidata in P. trituberculatus showed cumulative mortality rates of 100%, 75%, and 35%, respectively, after 120 hours of infection. The hemolymph of the deceased P. trituberculatus following injection with strain V. natriegens or V. fortis exhibited a light blue and did not coagulate normally. Conversely, the hemolymph of the deceased crabs following injection with strain M. bicuspidata appeared milky white and normal coagulation. Histopathology examination demonstrated that strains V. natriegens, V. fortis, and M. bicuspidata can all induce lesions in several tissues. This study is the first to isolate V. natriegens and V. fortis from crustaceans, and the infection tests on the P. trituberculatus can replicate the symptoms, such as hemolymph noncoagulation. Based on these findings, it is speculated that the pathogens capable of casing hemolymph noncoagulation syndrome in P. trituberculatus may originate from wild C. japonica. The drug resistance and probiotic antagonism test results can provide a theoretical basis for precise medication and offer insights into the development and application of probiotic preparations targeting the three pathogens
Effects of Short-Term Temperature Stress on Metabolic and Digestive Enzymes Activities of <em>Procambarus clarkii</em>
No full textTo investigate the effects of temperature stress on metabolic and digestive enzyme activities of Procambarus clarkii, the test species was transferred from 20°C (control group) to 10°C and 30°C, and samples were collected at 0, 3, 6, 12, 24, and 48h. The activities of pyruvate kinase (PK), hexokinase (HK) and hosphoenolpyruvate carboxykinase (PEPCK) in muscle and hepatopancreas of Procambarus clarkii was determined. The changes in α-amylase (α-AMY) and lipase (LPS) activity in intestinal and hepatopancreas were also examined. The results showed that the activities of digestive and metabolic enzymes in Procambarus clarkii were significantly affected by extreme water temperature (P). During the whole experimentation period, PK, HK, and PEPCK activities in the low-temperature group (10°C) were lower than those in the control group (20°C) (P ). Meanwhile, LPS and α-AMY activities in the low-temperature group (10°C) were also significantly lower than those in the control group (20°C) (P ). In the high-temperature group (30°C), the activities of PK, HK, and PEPCK metabolic enzymes in muscle and hepatopancreas decreased first. Then they increased, and their activity levels were significantly lower than those in the control group (P). At the same time, the activities of LPS and α-AMY digestive enzymes in the intestines and hepatopancreas were significantly lower than those in the control group(P). In summary, this study examined the impact of temperature stress on the metabolic and digestive enzyme activities in Procambarus clarkii, shedding light on its self-regulation mechanisms in response to temperature fluctuations. The findings provide a scientific foundation for understanding the species' adaptation to environmental changes
Application of Bacteriophages to Treat Toxic Gas-producing Bacteria <em>Desulfovibrio</em> spp. in Shrimp Ponds
Get PDFDesulfovibrio spp. bacteria pose significant challenges in shrimp aquaculture by producing hydrogen sulfide (H2S), which depletes oxygen levels and hinders shrimp growth. The increasing prevalence of antibiotic-resistant bacteria necessitates the exploration of alternative control methods. This study investigates the potential of bacteriophages as a biological solution to inhibit Desulfovibrio spp. in shrimp ponds. Six bacteriophage strains (ST231, ST22, φMix 1, φS8, φS9, and φMix 2) were evaluated using plaque assays at three time points (3, 6, and 18 hours). Results demonstrated that most bacteriophages significantly reduced bacterial density over time, with ST22 showing the most substantial inhibition (pDesulfovibrio spp., specifically Deltaproteobacteria and Desulfobacteraceae. The study also found that bacteriophage treatment led to decreased H2S and NH3 levels and increased dissolved oxygen in simulated pond environments. Morphological changes in bacterial colonies post-treatment further supported the phages' inhibitory effects. These findings suggest that bacteriophage ST22 is a promising biological alternative to antibiotics for preventing and controlling diseases caused by Desulfovibrio vulgaris in shrimp aquaculture, though further research is needed to assess long-term ecological impacts and efficacy in complex pond ecosystems
Digitalization and Operational Efficiency in Fisheries: Evidence from China
Get PDFFisheries contribute significantly to the global economy while playing a crucial role in environmental conservation, food security, and socio-economic development. Analyzing the operational efficiency of the fisheries industry not only enhances its economic and social benefits but strengthens the sector's capacity for sustainable growth. This study initially evaluates the operational efficiency of Chinese fishery-listed companies using the DEA-BCC model and Malmquist index, both statically and dynamically, from 2012 to 2022. It then investigates the impact of digital transformation on the operational efficiency of these companies using the Tobit regression model. The findings reveal that the mean values of comprehensive, technical, and scale efficiency for Chinese fishery-listed firms are below 1, with scale efficiency exhibiting particularly low mean values under static conditions. Additionally, during the observation period, these companies' average total factor productivity decreased by 0.1% annually compared to the base period. From a dynamic perspective, the decline in total factor productivity can primarily be attributed to reduced technical efficiency resulting from decreased scale efficiency. Ultimately, it can be reasonably concluded that the operational efficiency of listed fishing firms can be significantly enhanced by implementing digital transformation. This underscores the potential of digitalization as a critical factor in advancing the fisheries sector, facilitating modernization, and enabling intelligent upgrading across the industry
