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To improve the utilization of by-products of the Hyriopsis cumingii, this study investigated the effect of Hyriopsis cumingii polysaccharide (HCP) on the proliferation and migration of normal cells, as well as its reparative effects on ultraviolet radiation-B (UVB)-damaged cells. First, HCP was isolated and purified using DEAE Cellulose-52 column chromatography, Sephadex G-100 column chromatography and nanofiltration. Then, structural analysis was conducted using high-performance liquid chromatography, high-performance gel permeation chromatography, and infrared spectroscopy. Following this, cell proliferation experiments, cell scratch tests, UVB damage experiments, and protein expression analyses were employed to explore the anti-UVB damage effects and corresponding mechanisms of polysaccharide components. The results indicated the three substances obtained by isolation and purification were all homogeneous polysaccharide components. Among them, HCP-2 played a major role in promoting cell proliferation in HCP and facilitated the migration of HaCaT cells. The recovery of UVB-damaged cell vitality was raised by the increasing concentration of HCP-2. Furthermore, the reparative effect was more substantial than the protective effect at the same sample concentration. It was also observed that HCP-2 up-regulated the expression of the anti-apoptotic protein bcl-2 while inhibited the expression of apoptosis-related proteins casp9, p-Akt, and p-p38, indicating that HCP-2 could repair HaCaT cells by regulating apoptosis of cells damaged by UVB. In conclusion, HCP had the ability to inhibit cell apoptosis which provide a theoretical basis for its future application in the development of food and health products.

This study aimed to investigate the impact of acute velocity stress on the exercise physiology of mandarin fish (Siniperca chuatsi). Initially, the relative critical swimming speed (U’crit) was estimated to be around 4.87 body lengths per second (bl/s), while the relative burst swimming speed (U’burst) reached approximately 8.60 bl/s. Then, the results showed that as the flow velocity increased, the oxygen consumption rate (MO2) of mandarin fish gradually elevated, while the cost of transport (COT) displayed a decreasing trend. Subsequently, four groups were established for the experiment, including control group (0 %Ucrit), low flow velocity (20 %Ucrit), medium flow velocity (50 %Ucrit) and high flow velocity (80 %Ucrit). The results showed that with the increase of flow velocity, the content of muscle glycogen decreased gradually and the content of muscle lactate increased significantly. Furthermore, the results of serum myocardial enzymes and antioxidant enzymes showed that the levels of creatine kinase (CK), total antioxidant capacity (T-AOC) and glutathione peroxidase (GSH-Px) exhibited an initial increase followed by a decrease. During the examination of the gills, the highest level of Na+-K+-ATPase was reached at 80 %Ucrit, while the content of malondialdehyde (MDA) was significantly reduced. Additionally, transcriptomic sequencing was conducted on 0 %Ucrit and 80 %Ucrit groups, resulting in the identification of 101 upregulated genes and 116 downregulated genes. KEGG enrichment analysis revealed that the differentially expressed genes (DEGs) were significantly enriched in lipid metabolism and signal transduction. Finally, it was observed that the MAPK signaling pathway within the signaling transduction pathway exhibited the highest number of annotated DEGs. In general, it can be inferred that mandarin fish may regulate lipid peroxidation levels, and MAPK signaling pathway as an adaptive response to mitigate the effects induced by acute velocity stress. The above research is of great significance for improving the farming method of mandarin fish.

The effect of underwater noise environment generated by equipment in industrial recirculating aquaculture systems (RAS) on fish is evident. However, different equipment generate noise in various frequency ranges. Understanding the effects of different frequency ranges noise on cultured species is important for optimizing the underwater acoustic environment in RAS. Given this, the effects of underwater noise across various frequency bands in RAS on the growth, physiology, and collective behavior of juvenile largemouth bass (Micropterus salmoides) were comprehensively evaluated here. In this study, three control groups were established: low-frequency noise group (80–1000 Hz, 117 dB re 1μPa RMS), high-frequency noise group (1–19 kHz, 117 dB re 1μPa RMS), and ambient group. During a 30-day experiment, it was found that: 1) industrial RAS noise with different frequency bands all had a certain inhibitory effect on the growth of fish, which the weight gain rate and product of length and depth of caudal peduncle in the ambient group were significantly higher than those of the two noise groups, with the low-frequency noise group showing significantly lower values than the high-frequency noise group; 2) industrial RAS noise had a certain degree of adverse effect on the digestive ability of fish, with the low-frequency noise group being more affected; 3) industrial RAS noise affected the collective feeding behavior of fish, with the collective feeding signal propagation efficiency and feeding intensity of the noise groups being significantly lower than those of the ambient group, and the high-frequency noise group performing better than the low-frequency noise group as a whole therein. From the above, the underwater noise across different frequency bands generated by equipment operation in industrial RAS both had an impact on juvenile largemouth bass, with the low-frequency noise group being more severely affected.

Medium-chain monoglycerides (MG) have been reported to affect the productive performance, gut microbiota and health of broiler chickens reared in ideal experimental conditions at home and abroad. However, the effects of MG on performance, intestinal development and gut microbiota of chickens in large-scale farms during different feed stages remain unknown. The present study was conducted on a modern farm with a total of 12,000 yellow feathered broiler chicks that were randomly allotted to 2 groups (1000 chicks/replicate, 6 replicates/group) for a 70-day trial. The control group (CON group) received a basal diet, and the treated group (MG group) was fed a basal diet containing 300 mg/kg mixed MG. The results revealed that dietary MG significantly (P

Aquaculture systems, replete with equipment noise originating from aerators, pumps, feeders, and filtration systems, are known to exert substantial influence on fish behavior and growth. In this research, the focus was directed towards comprehending the impacts of aerator noise on the swimming, feeding, and growth progression of largemouth bass. In the course of a 50-day experimental period, the bass population was segmented into two groups: aerator noise (90.3dB re μPa RMS-1) and ambient noise (70.4dB re μPa RMS-1). The findings indicated discernible disparities in the swimming behavior and feeding between the two groups. Specifically, bass in the noise group maintained greater average angular distance and physical separation from their nearest counterparts than the bass in the ambient group, which were 43.61 ± 1.89° and 85.47 ± 1.72mm for the ambient group and 48.32 ± 0.49° and 97.01 ± 0.57mm for the noise group. Furthermore, the feeding kinetic energy was markedly lower in the noise group as compared to the ambient group. For the first time, the Shannon-Wiener diversity index was leveraged to gauge the diversity of fish swimming behavior, with the results signifying the diversity index of the noise group was 2.69 ± 0.07 higher than that of the ambient group, which was 2.51 ± 0.02. Lastly, the noise group demonstrated compromised growth performance, with a significantly lower average weight as opposed to the ambient group, along with marked variations in the specific growth rate. These findings offer a telling revelation about the profound impacts of aerator noise on the behavioral and growth of largemouth bass, thereby forming a valuable referential base for future research centered on the effects of noise pollution on aquatic organisms.

In recent years, government investments in implementing restrictive public policies on the treatment and discharge of effluents from the aquaculture industry have increased. Hence, efficient and cleaner methods for aquaculture production are needed. Recirculating aquaculture systems (RAS) offers water conservation by recycling the treated aquaculture water for reuse. RAS wastewater treatment using a moving bed bioreactors (MBBRs) process has been considered well suited for maintaining good water quality, thereby making fish farming more sustainable. Currently, improvements were achieved in tackling the influence of salinity, organic matter, disinfectant, and bioreactor start-up process on the MBBR performance efficiency. This review highlights an updated overview of recent development made using MBBR to treat the residual water from RAS. Precisely, nitrification and simultaneous nitrification-denitrification (SND), and other hybrid processes for nitrogen removal were elucidated. Finally, future challenges and prospects of MBBRs in RAS facilities that need to be considered were also proposed.

Feed has the greatest impact on the carbon footprint of the aquaculture, and also determines the water quality in aquaculture to a great extent. Making appropriate feeding control strategies is one of the most effective ways to promote cleaner production as well as fish welfare in aquaculture. Reliable and accurate fish appetite grading especially based on time-limited data is a prerequisite for achieving high-precision and reasonable feeding control in practical production. To date, however, few efforts have been done on this challenge. For these, regarding Micropterus salmoides as the experimental fish, a novel and practical method, based on a modified kinetic energy feature-based graph convolutional network (GCN), was developed in this study. First, graphs were constructed based on the extracted modified kinetic energy features and their temporal correlation. Then, with the help of a series of the convolution and global pooling operations, a GCN model was customized based on the constructed graphs. Following this, the customized GCN model was enriched by the self-attention pooling mechanism and customized network structure. Results show that the proposed GCN-based approach outperforms other typical state-of-the-art methods in fish appetite grading, and the grading accuracy obtained here could be 98.60% using only the first 4.2 seconds as well as the first 8.3 seconds of input data, which is not much different from that (98.89%) using full-length (25 second-long) input data. What’s more, compared to the recurrent neural network (RNN)-based method which performance is closest to our method, the space complexity of the proposed approach here can better satisfy the requirements of real aquaculture, in which the quantity of the trainable parameters here is only 6.4% ~ 31.8% of the RNN-based method. In summary, the proposed modified kinetic energy feature-based GCN approach is favorable for the appetite grading of fish like Micropterus salmoides with time-limited data, which is a promising approach in dealing with feeding control tasks and alleviating the water environmental burden in aquaculture.

Sound has a potential impact on animal welfare and production, but the impacts of soundscapes on aquaculture species in different aquaculture production systems have been rarely studied. This study investigated the impact of varying aquaculture soundscapes on largemouth bass (Micropterus salmoides). Three soundscapes were administered to replicated tanks: Recirculating Aquaculture System (RAS:107.7 dB re 1 Pa RMS), In-Pond Raceway System (IPRS:115.1 dB re 1 Pa RMS), and Ambient (70.4 dB re 1 Pa RMS) as the control. The initial weight of fish in the three groups was 3.59 ± 0.30 g. Following a 50-day experimental period, the average weight of the Ambient group (14.08 ± 0.13 g) was significantly greater than that of the IPRS group (12.79 ± 0.08 g) (p < 0.05). Examination of physiological samples revealed that the soundscape negatively impacted the fish’s immunological, anti-oxidation, and digestive enzymes. Furthermore, the external noise also influenced the locomotive patterns of the fish aggregations. Fish polarity and cohesion were significantly more discrete (p < 0.05) in both the RAS (47.79 ± 2.34° and 98.52 ± 3.22 mm) and IPRS groups (48.04 ± 0.70° and 87.70 ± 7.31 mm) compared to the Ambient group (42.76 ± 1.42° and 85.73 ± 1.57 mm). These results highlight the significant impacts of the aquaculture soundscape on the development, physiological activities, and behavioral traits of largemouth bass. Future research should focus on determining and optimizing the impact of different equipment noise to ensure optimal welfare and production performance in aquaculture systems.

The feeding method is of great significance for aquaculture production and cost. In recent years, research on intelligent feeding, a method based on fish appetite, has been trending. Few studies, however, have focused on fish welfare issues that can result from intelligent feeding. In this study, an adaptive feeder based on a practical intelligent feeding method was designed to evaluate whether this intelligent feeding method would impair fish welfare compared to traditional automatic feeding. The results indicated that the amount of residual feed and size inhomogeneity in the traditional group was significantly higher than that in the intelligent group. The results of the growth indicator showed that the weight gain rate (WGR) in the intelligent feeding group was significantly higher (30.17%) than in the traditional feeding group. Although no significant differences were observed in the survival rate (SR), the condition factor (CF) and the hepatosomatic index (HSI), the specific growth rate (SGR) in the intelligent feeding group was significantly increased by 8.33% while the feed conversion rate (FCR) was reduced by a remarkable 17.07% compared to the traditional feeding group. Moreover, intelligent feeding significantly improved the pepsin activity of the bass. In terms of immunity and antioxidant capacity, however, the fish in the intelligent feeding group had a significantly lower lysozyme (LZM) level than those fed with the traditional method. For superoxide dismutase (SOD), the intelligent group also displayed a lower activity value, although it was not significant. The intelligent feeding group had 0.14 nmol/mg protein higher malondialdehyde (MDA) activity than the traditional group. Regarding stress, although no statistical significance was observed, the cortisol level in the intelligent group was 1.9 ng/ml higher than in the traditional group. Together, these data suggested that the intelligent feeding method can significantly improve fish growth but may also result in stress and suppress innate immunity.

It is critical to exploit technologies for alleviating watermelon continuous cropping obstacle which frequently occurs and results in the limiting production and economic losses of watermelon. This study aimed to explore the effects of slightly acidic electrolyzed water (SAEW) on watermelon continuous cropping obstacles. The results showed that SAEW significantly improved the growth of watermelon seedlings cultivated in continuous cropping soil and caused a mass of changes to the diversity of the soil microbial community. Compared with Con, SAEW decreased the diversity index of bacteria by 2%, 0.48%, and 3.16%, while it increased the diversity index of fungus by 5.68%, 10.78%, and 7.54% in Shannon, Chao1, and ACE index, respectively. Besides, the enrichment level of Fusarium oxysporum f. sp. niveum (FON) was remarkably downregulated by 50.2% at 14 days of SAEW treatment, which could decrease the incidence of Fusarium wilt disease. The wet and dry weights of FON mycelia in the fluid medium were depressed more than 93%, and the number of FON colonies in continuous cropping soil was reduced by 83.56% with SAEW treatment. Additionally, a strong correlation between watermelon, FON, and SAEW was presented by correlation analysis. Furthermore, the content of endogenous reactive oxygen species (ROS) was over quadruply increased by SAEW, which may contribute to the sterilizing effect of SAEW on FON. Taken together, our findings demonstrated that exogenous SAEW could alter the soil microbial diversity and decrease the accumulation of FON, which improved the growth of watermelon seedlings and finally alleviated continuous cropping obstacles of watermelon.

The vaginal microbiota, dominated by Lactobacilli, plays an important role in maintaining women's health. Disturbance of the vaginal microbiota allows infection by various pathogens such as Gardnerella spp. (GS) and related anaerobic bacteria resulting in bacterial vaginosis (BV). At present, the treatment options for BV are extremely limited. Treatment of antibacterial drugs and vaginal acidification are the two primary therapeutic methods. Acid electrolyzed water (AEW) is known to inactivate microorganisms and is considered a medical application in recent years. Studies have found that Lactobacillus acidophilus (LA) probiotics helps to inhibit GS-induced BV. Our study took GS and LA as the research object, which aims to explore AEW as a potential alternative therapy for BV and its underlying mechanisms. We first obtained the pH of AEW (3.71–4.22) close to normal vaginal pH (3.8–4.5) to maintain normal vaginal acidification conditions. Plate counting experiments showed that AEW (pH: 4.07, ORP: 890.67, ACC: 20 ppm) (20 ppm) could better inhibit the viability of GS but had a more negligible effect on LA. Then, we preliminarily explored the possible mechanism of AEW anti-GS using cell biology experiments and transmission electron microscopy. Results showed that the membrane permeability was significantly increased and the integrity of cell membrane was destroyed by AEW in GS than those in LA. AEW also caused protein leakage and cell lysis in GS without affecting LA. Meanwhile, AEW induced a number of reactive oxygen species (ROS) production in GS, with no obvious LA changes. Finally, we found that 20 ppm AEW exhibited excellent antibacterial effect on the vaginal secretions of women diagnosed with BV by Amsel criteria and sialic acid plum method. Taken together, our findings manifest that 20 ppm AEW has an excellent antibacterial effect in GS with less effect on LA, which might be expected to become a potential therapy for BV.

The head-to-tail orientation of spindle-shaped fry is an important part of automated vaccine injection. The fry’s automatic orientation helps reduce labor and improve efficiency during the automated injection. This paper designed an electromagnetic vibration fry orientation device for grass carp fry, measured its friction characteristics with three different materials in scales and against scales, analyzed the kinematic characteristics of the fry on the electromagnetic vibration feeder, and clarified the main factors affecting fry transport. It used the trough’s inclination angle, amplitude, and material as the test factors, whereas the orientation success rate and orientation rate were used as the evaluation index. Orthogonal combination tests were carried out with 90–150 mm grass carp fry as the research object to obtain reasonable parameter combinations. The results showed that the best orientation effect was achieved when the surface of the trough was a silicone film with many bumps, the inclination of the plate spring was β = 15°, the inclination of the trough plane was θy = −4°, and the amplitude A = 0.7 mm. In this parameter combination, the directional device was tested and verified. The targeted success rate was ε = 95.5%, and the direction rate was η = 0.87 tail/s. The device could meet the requirements of the head and tails during the mechanized injection of the fry.

Chicken muscle yield and amino acid composition improvements with medium-chain monoglyceride (MG) supplementation were reported by previous studies, but the underlying mechanism was uncertain. This study aimed to decipher chicken amino acid improvements induced by medium-chain monoglycerides in the views of metabolomics, gene expression, and the gut microbiome. Newly hatched chicks (12,000 chicks) were weighed and randomly divided into two flocks, each with six replicates (1000 chicks per replicate), and fed a basal diet (the control group, CON) or a basal diet enriched with 300 mg/kg MG (the treated group, MG). Results demonstrated that MGs significantly increased the chicken flavor and essential and total amino acids. The serum amino acids and derivatives (betaine, l-leucine, l-glutamine, 1-methylhistide), as well as amino acid metabolism pathways in chickens, were enhanced by MG supplementation. Gene expression analysis exhibited that dietary MGs could improve muscle protein synthesis and cell growth via the mTOR/S6K1 pathway. Dietary MGs enhanced the cecal amino acid metabolism by selectively increasing the proportion of genera Lachnospiraceae_NK4A136_group and Bacteroides. Conclusively, the present study demonstrated that dietary MGs improved chicken amino acid composition via increasing both gut amino acid utilization and muscle amino acid deposition.

Given the possibility that food contaminated with SARS-CoV-2 might become an infection source, there is an urgent need for us to develop a rapid and accurate nucleic acid detection method for SARS-CoV-2 in food to ensure food safety. Here, we propose a sensitive, specific, and reliable molecular detection method for SARS-CoV-2. It has a mechanism to control amplicon contamination. Swabs from spiked frozen shrimps were used as detection samples, which were processed by heating at 95 °C for 30 s. These preprocessed samples served as the templates for subsequent amplification. A colorimetric LAMP reaction was carried out to amplify both the SARS-CoV-2 target and the MS2 phage simultaneously in one tube. MS2 phage was detected by colorimetric LAMP as the internal control, while SARS-CoV-2 was detected with a CRISPR/Cas12a system. The fluorescence results could be visually detected with an ultraviolet lamp. Meanwhile, uracil was incorporated during the LAMP reaction to provide an amplicon contamination proof mechanism. This test could detect as low as 20 copies of SARS-CoV-2 in one reaction. Additionally, the detection could be finished in 45 min. The test only needs a heating block and an ultraviolet lamp, which shows the potential for field detection.

Fish vaccination plays a vital role in the prevention of fish diseases. Inappropriate injection positions will cause a low immunization rate and even death. Currently, traditional visual algorithms have poor robustness and low accuracy due to the specificity of the placement of turbot fins in the application of automatic vaccination machines. To address this problem, we propose a new method for estimating the injection position of the turbot based on semantic segmentation. Many semantic segmentation networks were used to extract the background, fish body, pectoral fin, and caudal fin. In the subsequent step, the segmentations obtained from the best network were used for calculating body length (BL) and body width (BW). These parameters were employed for estimating the injection position. The proposed Atten-Deeplabv3+ achieved the best segmentation results for intersection over union (IoU) on the test set, with 99.3, 96.5, 85.8, and 91.7 percent for background, fish body, pectoral fin, and caudal fin, respectively. On this basis, the estimation error of the injection position was 0.2 mm–4.4 mm, which is almost within the allowable injection area. In conclusion, the devised method was able to correctly differentiate the fish body from the background and fins, meaning that the extracted area could be successfully used for the estimation of injection position.

In this article, an autonomous robotic fish is designed for underwater operations like object detection and tracking along with collision avoidance. The computer-aided design model for prototype robotic fish is designed using the Solid Works® software to export an stereolithography (STL) file to MakerBot, a 3D printer, to manufacture the parts of robotic fish using polylactic acid thermoplastic polymer. The precise maneuverability of the robotic fish is achieved by the propulsion of a caudal fin. The oscillation of the caudal fin is controlled by a servomotor. A combination of visual and ultrasonic sensors is used to track the position and distance of the desired object with respect to the fish and also to avoid the obstacles. The robotic fish has the ability to detect an object up to a distance of 90 cm at normal exposure conditions. A computational fluid dynamics analysis is conducted to analyze the fluid hydrodynamics (flow rate of water and pressure) around the hull of a robotic fish and the drag force acting on it. A series of experimental results have shown the effectiveness of the designed underwater robotic fish.

Abstract Foodborne disease outbreak caused by food microbiological contamination is a serious public health problem. Slightly acidic electrolyzed water (SAEW), a new ultra-high effect and wide-spectrum disinfectant that is colourless, odourless, and harmless to humans and the environment, is directly used on food surfaces in Japan and America. However, the underlying inactivation mechanism remains unknown. In this study, biochemical and cellular changes were observed to investigate the bactericidal mechanism of SAEW against Escherichia coli (E. coli). The results indicated that SAEW with a pH of 6.40, an oxidation-reduction potential (ORP) of 910 mV, an available chlorine concentration (ACC) of 60 mg/L, and a volume ratio of 20:1, produced the most effective sterilization action. A fluorescence-based live-dead assay was further used to demonstrate the sterilized effect and the cell esterase activity damage caused by SAEW. During the observation period, within 10 min, the cell morphology changed, which was characterized by cell expansion, cell elongation and increased membrane permeability. Meanwhile, reactive oxygen substances (ROS) were released in the bacterial cells. E. coli inactivation and apoptosis induced by SAEW were observed. Our findings illustrate that the bactericidal effects of SAEW against E. coli occurred through cellular and biochemical mechanisms of cell necrosis and apoptosis.