[Objective]To solve the problems of imaging blurring and low detection accuracy in complex background of underwater target images,this study proposes an underwater target detection algorithm which integrates multiple attention mechanisms and Wise-IoUv3.[Method]Firstly,a multi-scale feature enhancement mechanism was designed in the backbone network,omni-dimensional dynamic convolution(ODConv)was used to replace some convolutions,and an efficient-scale attention mechanism(EMA)was introduced to enhance the backbone network's ability to extract features of blurred targets and small targets.Secondly,the spatial pyramid pooling-fast(SPPF)module was improved by adding an average pooling branch to supplement spatial information and enhance global context awareness.In addition,the lightweight BiFormer attention mechanism was integrated into the two branches to reduce the model's computational complexity and enhance the detection performance of small targets.Then,in the prediction stage,the original loss function was replaced by Wise-IoUv3 to balance the model training results of different quality images.Finally,the original detection head was replaced by the dynamic detection head(DynamicHead)to enhance the scale perception,spatial perception and task perception ability of the detection head and improve the accuracy of object position recognition.[Result]The experimental results on RUOD and URPC datasets show that the improved algorithm increases the mean average precision by 3.6%and 1.7%respectively,compared with the benchmark methods(especially YOLOv8n);the model's parameter count and computational cost are reduced by 0.26×106 and 0.4 GFLOPs,respectively.[Conclusion]The experimental results show that the proposed method reduces the missed-detection and false-detection of blurred targets and small targets in complex situations,thus improving the detection and maintaining the model's lightweight design.
Crassostrea hongkongensis (C. hongkongensis) is one of the three most commonly cultivated oyster species in China. Seasonal hypoxia is one of the most serious threats to its metabolism, reproductive behavior, and survival. To investigate the effects of hypoxia stress on the antioxidant capacity and energy metabolism of C. hongkongensis, the total antioxidant capacity (T-AOC), glycogen content, and enzyme activities (phosphofructokinase, PFK; pyruvate kinase, PK; phosphoenolpyruvate carboxykinase, PEPCK) of oysters were determined under normoxic (DO 6 ± 0.2 mg/L) and hypoxic (DO 1.5 mg/L) conditions at 0 h, 6 h, 48 h, and 72 h. We also determined the T-AOC, glycogen content, and enzyme activities of oysters under reoxygenation (recovered to normoxia for 24 h). To further examine the potential molecular regulatory mechanism of hypoxic adaptation, a transcriptome analysis was conducted on the gill of C. hongkongensis under normoxia (N, 72 h), hypoxia (H, 72 h), and reoxygenation (R). After being exposed to hypoxia for 6 h, the T-AOC, glycogen content, and enzyme activities of PK, PFK, and PEPCK in C. hongkongensis were significantly decreased. However, after prolonging the duration of hypoxia exposure for 72 h, the T-AOC, glycogen content, and enzyme activities increased compared to that of 48 h. After 24 h reoxygenation, the T-AOC, glycogen content, and enzyme activity of PK and PFK returned to close to initial levels. In addition, a transcriptome analysis discovered 6097 novel genes by mapping the C. hongkongensis genome with the clean reads. In total, 352 differentially expressed genes (DEGs) were identified in the H vs. N comparison group (235 upregulated and 117 downregulated genes). After recovery to normoxia, 292 DEGs (134 upregulated and 158 downregulated genes) were identified in the R vs. N comparison group, and 632 DEGs were identified (253 upregulated and 379 downregulated genes) in the R vs. H comparison group. The DEGs included some hypoxia-tolerant genes, such as phosphoenolpyruvate carboxykinase (PEPCK), mitochondrial (AOX), tyramine beta-hydroxylase (TBH), superoxide dismutase (SOD), glutathione S-transferase (GST), and egl nine homolog 1 isoform X2 (EGLN1). Additionally, DEGs were significantly enriched in the KEGG pathways that are involved in hypoxia tolerance, including the metabolism of xenobiotics by cytochrome P450 pathways and the HIF-1 signaling pathway. Then, we selected the five hypoxic-tolerant candidate DEGs for real-time quantitative polymerase chain reaction (RT-qPCR) validation, and the results were consistent with the transcriptome sequencing data. These discoveries have increased our understanding of hypoxia tolerance, recovery ability after reoxygenation, and molecular mechanisms governing the responses to hypoxia in C. hongkongensis.
[Objective]The aim of this study is to study the ameliorative effect of docosahexaenoic acid-enriched phosphatidylcholine(DHA-PC)on bisphenol S(BPS)-induced liver injury in mice.[Methods]C57BL/6 mice(n = 24)were randomly divided into control group,model group and administration group with 8 mice in each group.The model group and administration group were given 5 mg·(kg·d)-1 BPS for 10 weeks,respectively,at the same time,the administration group was given 80 mg/kg DHA-PC.The protective effect of DHA-PC[80 mg·(kg·d)-1]on BPS-induced liver injury in mice was studied by monitoring the food intake and body weight of mice,liver function and liver histopathological analysis,inflammatory factors,lipids and oxidative stress in liver tissue.[Results]After BPS treatment,the body mass,liver index and epididymal fat index of mice were significantly increased(P<0.05),and after DHA-PC treatment,these indices showed a downward trend.There was no difference in food intake or energy intake among the three groups(P>0.05).Pathological results showed that the hepatic cord disappeared and focal fatty lesion occurred in the model group,while the hepatic cord recovered and central vein reappeared in the administration group.Compared with the model group,the contents of alanine aminotransferase(ALT),aspartate aminotransferase(AST),interleukin(IL)-1β,IL-6,tumor necrosis factor(TNF)-α,cholesterol(TC),triglyceride(TG),free fatty acid(NEFA),low-density lipoprotein cholesterol(LDL-C)and malondialdehyde(MDA)were significantly decreased after DHA-PC treatment(P<0.05).The contents of high-density lipoprotein cholesterol(HDL-C),total antioxidant capacity(T-AOC),superoxide dismutase(SOD),glutathione peroxidase(GSH-Px)and catalase(CAT)were significantly increased after DHA-PC treatment,compared with the model group(P<0.05).[Conclusion]DHA-PC from herring roe can effectively improve BPS-induced liver injury in mice by inhibiting inflammation,improving lipid metabolism disorder and oxidative stress.
[Objective]The aim of this paper is to explore the effects of dietary phospholipid level on growth performance,antioxidant capacity,fatty acid composition and lipid metabolism of juvenile snakehead(Channa argus).[Methods]Snakehead fry with an initial body mass of(3.99±0.01)g were fed with five iso-nitrogenous and iso-lipidic diets prepared by adding 0,2%,4%,6%and 8%phospholipids to the basal diet,respectively designated as group PL0(control group),PL2,PL4,PL6 and PL8.At the end of the 43-day's culture experiment,the growth indicators,physiological and biochemical indicators and the expression levels of lipid metabolism-related genes in the liver of the juvenile snakehead were measured.[Results]1)The addition of phospholipids in the diet significantly affected the growth performance of juvenile snakehead.The final body mass and specific growth rate of the juvenile snakehead in group PL4 and group PL6 were significantly higher than those in group PL0(P<0.05).The daily feed intake(FI)and feed conversion ratio(FCR)showed a trend of decreasing first and then increasing.The FI in group PL4 was the lowest,and the FCR in group PL6 was the lowest,both of which were significantly lower than those in group PL0(P<0.05).Meanwhile,the viscerosomatic index(VSI)of the fry in group PL8 was significantly lower than that of the other groups(P<0.05).2)With the increase of dietary phospholipid level,the increase of phospholipid content in the diet significantly reduced the crude fat content of the whole fish and liver,while the moisture showed the opposite trend(P<0.05).3)With the increase of dietary phospholipid level,the malondialdehyde content in the liver decreased more significantly in groups PL6 and PL8 than in the other groups(P<0.05);the superoxide dismutase activity in the liver increased more significantly in group PL8 than in the other groups(P<0.05);the total antioxidant capacity increased first and then decreased,and the capacity in group PL2 was significantly higher than that of the other groups except PL6(P<0.05);the catalase activity was not affected by the change of phospholipid content in the diet(P>0.05).4)The addition of phospholipids in the diet significantly increased the n-3PUFA content of the fish body and liver(P<0.05).5)The addition of phospholipids also had a significant effect on the expression of lipid metabolism-related genes in the liver.The expression level of acc1,a lipid synthesis-related gene,in group PL8 was significantly lower than that in PL0 group(P<0.05);the expression levels of mgl and hsl,lipid degradation-related genes,in groups PL4 and PL6 were significantly higher than those in group PL0(P<0.05),and hsl in group PL6 was significantly higher than that in group PL0(P<0.05);the expression levels of pparα,cpt1 and aco,fatty acid oxidation-related genes,in group PL6 were significantly higher than those in group PL0(P<0.05).[Conclusion]Adding phospholipids to the diet can significantly improve the growth performance of juvenile snakehead,and enhance their antioxidant capacity and reduce lipid deposition by regulating lipid metabolism.The suitable dietary phospholipid requirement for juvenile snakehead was 5.36%.
[Objective]The aim of this study is to explore the effects of two leguminous green manure(Vicia villosa Rothvar and Vicia sativa L.)feed on the growth performance and meat quality of Procambarus clarkii.[Methods]The effects of leguminous green manure addition on growth performance,physicochemical properties and tissue structure of crayfish were analyzed after 60 days of feeding with five feed treatment groups(group T1:V.villosa,group T2:V.sativa,group T3:specialized feed,group T4:V.villosa + specialized feed,group T5:V.sativa + specialized feed).[Results]The results showed that the protein contents of V.villosa and V.sativa were 27.80%and 25.00%,the crude fiber contents of both were 22.60%,and the contents of aspartic acid and leucine were relatively high.After 60 days of feeding,compared with feeding the specialized diet(group T3),there was no significant change in the survival rate of crayfish in different groups(76.7%-80.0%,P>0.05),but the mass gain rate increased significantly by 8.13%,32.92%and 27.95%in groups T1,T4 and T5,respectively(P<0.05),and the meat gain rate increased significantly by 9.29%in group T2(P<0.05);the pressurized water loss rate significantly decreased by 20.6%and 18.8%in groups T4 and T5,respectively(P<0.05),and the color and lustre increased to some extent in all groups except for a decrease in the L* value in group T1,and the crayfish meat muscle fiber interstitial space decreased and shrimp meat became more compact in groups T4 and T5.[Conclusion]The feed mixture was better than the specialized feed or leguminous green manure alone,and the growth performance and meat quality of crayfish were better fed by V.sativa + specialized feed than V.villosa + specialized feed.
