The NLR family pyrin domain containing 3 (NLRP3) inflammasome's activation is essential for fish liver damage brought on by a high-fat diet. Despite naringenin's potential to block NLRP3 inflammasome activation, its preventive effects against fish liver damage caused by a high-fat diet and the underlying processes are yet unknown. To address this, six experimental diets were formulated: a normal-fat diet (10 % lipid, control) and five high-fat diets (18 % lipid, HF) supplemented with 0 %, 0.005 %, 0.01 %, 0.02 %, and 0.04 % naringenin. Each diet was randomly given to three tanks (30 fish/tank). After an eight-weeks feeding trial, the HF did not affect growth performance but induced hepatic and intestinal oxidative stress, ultrastructural damage, hepatocyte apoptosis, hepatic inflammation, and gut dysbiosis (P < 0.05). Dietary supplementation with naringenin (0.005 %-0.02 %) significantly attenuated hepatic oxidative stress by reducing malondialdehyde (MDA) content and increasing total superoxide dismutase (T-SOD) activity, while also suppressing hepatic inflammation through downregulating the exprssion of NLRP3 inflammasome-related markers (P < 0.05). Furthermore, 0.02 % naringenin ameliorated hepatic ultrastructure, reduced hepatocyte apoptosis, and improved gut microbiota composition by decreasing Mycoplasma abundance and increasing beneficial genera (e.g., Bacillus, Lactobacillus, and Weissella) abundance (P < 0.05). The correlation analysis revealed that estrogen receptor alpha (ER alpha) was negatively correlated with NLRP3 inflammasome activation and that microbiota enriched in the 0.02 % naringenin group were positively correlated with improved liver health indicators (P < 0.05). In conclusion, naringenin effectively alleviates HF-induced liver damage in fish by regulating oxidative stress, NLRP3 inflammasome, and gut microbiota, and may serve as a promising feed additive in aquaculture.

Nanoplastics (NPs) are emerging as significant environmental hazards, especially in aquatic ecosystems, where they predominantly exist in aged forms due to weathering processes. Fish, known for their remarkable ability to regenerate injured caudal fins through intricate biological mechanisms, serve as an ideal model for studying sublethal effects of environmental pollutants. This study investigates the toxic impacts of aged polystyrene nanoplastics (PS-NPs) on caudal fin regeneration in goldfish, focusing on molecular, cellular, and physiological responses. Goldfish were exposed to UV-aged PS-NPs (50 nm) at concentrations of 0, 10, 100, and 1000 μg/L, and regeneration was monitored at 7-, 14-, and 35 days post-amputation (dpa). Results demonstrated that caudal fin regeneration was significantly impaired in a concentration- and time-dependent manner. Under exposure to a low concentration (10 μg/L) of aged PS-NPs, goldfish showed an adaptive antioxidant response. Exposure to medium-high concentrations (100-1000 μg/L) led to abnormal ROS activity, disordered apoptosis, and abnormal transcription of core genes in oxidative stress (gpx, sod), immune-inflammation (mpeg1, il-1β, tnf-α), and regeneration pathways (fgf20a, runx2a). This ultimately led to a significant inhibition of caudal fin regeneration at 35 dpa. This study indicates that UV-aged PS-NPs can inhibit the regeneration of goldfish tail fins by disrupting the coordinated function of the oxidative stress-immune-apoptosis-regeneration pathway. The study highlights the risks posed by aged NPs in aquatic environments, emphasizing their potential to impair critical tissue regeneration processes in fish, with broader implications for ecosystem health and resilience.

The purpose of this research was to investigate how adding dietary guar gum to high-lipid diets affected the fish growth and gut health of common carp ( Cyprinus carpio ). A normal-lipid diet (5% crude lipid; control) and four high-lipid diets (10% crude lipid) with 0% (high-fat [HF]), 0.3% (GG0.3), 1% (GG1), and 3% (GG3) of guar gum were developed and fed to fish (4.53 g) for 8 weeks. The findings showed that HF induced impairment of intestinal morphology and mucosal barrier, oxidative stress, gut dysbiosis, and gut inflammation. Compared to the HF, guar gum-containing diets substantially improved gut villus height, upregulated the expression levels of nuclear factor erythroid 2-related factor 2 and zonula occludens-1 , and downregulated the expression levels of toll-like receptor 1 ( tlr1 ), tlr5 , myeloid differentiation factor 88 , interleukin-1β ( il-1β ), il-6 , and il-8 . Moreover, the GG0.3 and GG1 diets dramatically increased catalase (cat) and occludin expression levels. Furthermore, the GG1 and GG3 diets improved the microbiota composition by increasing Fusobacteria and Cetobacterium abundance while lowering Proteobacteria, Acidovorax , Acinetobacter , Serratia , and Comamonas abundance. Correlation analysis revealed that guar gum improved gut health by modulating gut microbiota and tight junction proteins. The findings indicated that guar gum can ameliorate HF diet-induced intestinal damage in fish.

Astragalus polysaccharides (APS) have been widely studied as immunostimulants in aquaculture, but their comprehensive effects on growth, immunity, intestinal microbiota, and disease resistance in largemouth bass (Micropterus salmoides) remain unclear. In this study, largemouth bass (2.7g) were fed diets supplemented with 0.0%, 0.1%, 0.2%, 0.4%, or 0.8% APS for 73 days, followed by an Aeromonas hydrophila challenge. The results indicated that dietary addition of 0.1%-0.4% APS significantly enhanced fish growth and antioxidant capacity, while alleviating inflammatory responses and enhancing immune-related gene expression in the spleen (P < 0.05). Furthermore, fish fed 0.1%–0.2% APS exhibited higher survival after A. hydrophila challenge (P < 0.05). Dietary supplementation with 0.1% APS also altered intestinal microbiota composition by increasing beneficial bacteria (e.g., Clostridium sensu stricto 1) and reducing potentially harmful bacteria (e.g., Achromobacter and Pedobacter). A broken-line regression analysis based on specific growth rate and cumulative mortality after A. hydrophila challenge indicated that the estimated optimal dietary APS level was approximately 0.09%–0.095% for largemouth bass. Overall, dietary APS supplementation improved growth performance, antioxidant status, immune responses, disease resistance, and intestinal microbiota composition in largemouth bass, suggesting its potential application as a functional feed additive in aquaculture.

The study aimed to investigate the optimal concentration of selenium fertilizer for alleviating polyethylene nanoplastics (PE-NPs) induced nutritional inhibition in alfalfa (Medicago sativa). Alfalfa seeds were randomly divided into six groups, with three replicates per group and 15 plants per replicate. The control group (group CK) did not add PE-NPs. The experimental groups added 1% PE-NPs to the soil and applied selenium fertilizers of 0 (group S0), 0.4 (group S0.4), 0.8 (group S0.8), 1.2 (group S1.2), and 1.6 mg/kg (group S1.6), respectively. The results showed that compared with the group CK, the aboveground biomass, net photosynthetic rate, the content of chlorophyll a, chlorophyll b, dry matter, crude ash, crude protein, and crude fat in group S0 were significantly reduced (P<0.05). Compared with the group S0, the net photosynthetic rate in group S0.4 was significantly increased (P<0.05). The group S0.8 achieved the highest membership function value, indicating optimal comprehensive performance. The study demonstrates that soil application of 0.8 mg/kg selenium fertilizers can significantly alleviate the physiological inhibition caused by PE-NPs, and improve the nutritional quality of alfalfa.

Microplastics (MPs) are emerging pollutants with pervasive respiratory exposure routes, yet their lung-specific toxicity mechanisms remain poorly defined. This study aims to investigate the size-dependent detrimental effects on pulmonary systems using in vivo (mice) and in vitro (coculture) models, simulating acute (single dose) and subchronic (28-day) exposures. Crucially, we identify epithelial-mesenchymal transition (EMT) as a novel cytotoxic mechanism and delineate the ECM-MMP signaling cascade as the primary driver of PS-MP-induced lung injury. In vivo, acute intratracheal exposure to 12 mg/kg PS-MPs (with 1 µm particles) resulted in weight loss (9.09 % vs. controls). PS-MPs accumulated dominantly in lungs, with 1 µm particles depositing 1.38-fold higher than 10 µm particles (quantitative result). Subchronic exposure (8 mg/kg) triggered particle-size-dependent pathology. 1 µm PS-MPs increased lung injury scores by 2.5-fold vs. 10 µm. Myeloperoxidase (MPO) and malondialdehyde (MDA) rose by 2.13-fold (1 µm) vs. 1.81-fold (10 µm). In vitro, 1 µm PS-MP-exposed lung cells induced mitochondrial depolarization (ΔΨm loss: 50 %) and apoptosis (17 % increase). Critically, 1 µm PS-MPs potently activated MMPs (MMP-2↑180 %, MMP9↑250 %) via ECM-MMP dysregulation. Our findings reveal that PS-MPs drive lung injury through oxidative stress, cell apoptosis, and mitochondrial dysfunction in a strict size-dependent manner (1 µm > 5 µm > 10 µm), with the ECM-MMP axis as a central pathway. The signaling pathway activated by PS-MPs in lung injury suggested that PS-MPs induced proliferation inhibition, oxidative stress, and EMT via activating the ECM-MMP signaling cascade. In addition, EMT activation suggested a novel mechanism for the cytotoxicity of PS-MPs, hinting at the potential carcinogenic effect of these pollutants.

The hepatotoxicity of microplastics (MPs) has garnered increasing attention, but their effects on elderly organisms remain inadequately characterized, particularly concerning hepatic stress response patterns in environmental conditions. In this study, a 10-day exposure period of elderly zebrafish to polystyrene microplastics (PS-MPs, 1 mu m) was conducted, with exposure concentrations set at 5.6 x 10-7 mu g/L, 5.6 x 10-4 mu g/L, and 5.6 x 10-1 mu g/L. PS-MPs-induced toxicity varied with concentration: superoxide dismutase (SOD), complement 3 (C3), and complement 4 (C4) initially decreased before rising; 8-hydroxy-2-deoxyguanosine (8-OhdG), interleukin-6 (IL-6), and interleukin-8 (IL-8) increased at high concentrations. Additionally, catalase (CAT) activity and thiobarbituric acid reactive substances (TBARS) contents rose with concentration. The aged zebrafish liver exhibited differentiation driven by responsiveness; low levels cause homeostatic disruption, and high levels induce genotoxicity and immune activation. LC-MS identified twelve crucial metabolites involved in 18 metabolic pathways, including amino acids (L-tyrosine, l-arginine), lipids (phospholipids, 12(S)-leukotriene B4 and triglycerides), and N-acetylneuraminic acid, related to energy, immunity, and neurological health. Overall, elderly zebrafish exhibited clear dose-dependent thresholds and distinct physiological stress responses under varying concentrations of PS-MPs. These findings reveal how PS-MP exposure can affect physiological health and metabolism, offering critical insights into the ecological risks faced by aging organisms.

To explore the toxic effects of polystyrene microplastics (PS-MPs) on common carp ( Cyprinus carpio ), 0 µg/L, 50 µg/L, 100 µg/L, and 200 µg/L PS-MPs were designated as the control group (CK) and low, medium, and high concentration groups, respectively. Each group had 3 replicates and was exposed to PS-MPs for 15 days. The results showed that, compared with the control group, the weight gain rate and hepatopancreas somatic indices were significantly decreased in 100 and 200 μg/L PS-MPs groups, the visceral index was significantly decreased in 50 and 100 μg/L PS-MPs groups. In comparison to CK, experimental groups (50-200 µg/L PS-MPs) significantly decreased activity levels of acid phosphatase, alkaline phosphatase, and peroxidase while significantly increased activity levels of lysozyme, catalase, and superoxide dismutase. In addition, the malondialdehyde contents of the experimental carp increased significantly in 50 and 100 µg/L PS-MPs groups compared to CK. For hepatic amino acid contents, methionine, threonine, leucine, and isoleucine contents of the hepatopancreas of carp in PS-MPs groups were significantly lower than the control group. Correlation analysis showed that amino acids in the liver closely associated with fish growth, immune, and antioxidant-related indicators. In conclusion, PS-MPs above 50 µg/L in the water body could significantly affect normal growth, weaken the activity of hepatopancreatic immunity-related enzymes and antioxidant capacity, and disturb the balance of amino acid metabolism in common carp. The findings provide valuable insights into optimizing feeding strategies, contribute to more sustainable aquaculture practices, and support the development of policies in aquatic ecosystems.

The investigation was to validate the alleviating effect of sodium butyrate on high-fat dietinduced gut injury and growth inhibition in largemouth bass (Micropterus salmoides). Five diets were designed: four high-fat diets (18 % crude lipid) supplemented with sodium butyrate at 0 % (HF), 0.05 % (HFS1), 0.1 % (HFS2), and 0.2 % (HFS3), as well as a control diet (C, 10 % crude lipid). Three tanks (30 fish each tank) were randomly allocated to each diet. Fish (4.0 g) were fed to apparent satiation for sixty days. Results indicated that HF dramatically reduced fish growth and induced oxidative stress, mucosal barrier dysfunction, gut inflammation, and gut dysbiosis compared to C. However, in comparison to HF, HFS1, HFS2, and HFS3 diets significantly promoted feed intake and weight gain rate, relieved oxidative stress by increasing antioxidant defense (e.g., total superoxide dismutase, catalase, glutathione peroxidase, reduced glutathione, and nuclear factor E2-related factor 2) and reducing malondialdehyde content, enhanced mucosal barrier by upregulating the expression of occludin, mucin3a, zona occluding-1, hypoxia-inducible factor-1 alpha, and lysozyme, and reduced inflammation by downregulating the expression levels of interleukin 1 beta and tumor necrosis factor alpha (P < 0.05). Moreover, HFS1 and HFS3 dramatically reduced Tenericutes and Mesomycoplasma abundance, whereas HFS1 increased Lactococcus abundance when compared to HF (P < 0.05). Correlation analysis revealed a significant relationship between fish growth and gut injury with mucosal barrier proteins and gut microbiota (e. g., Tenericutes, Mesomycoplasam, and Lactococcus) (P < 0.05). These findings suggested that sodium butyrate can help mitigate the detrimental effects of high-fat diets on fish growth and gut health.

Fishmeal is an indispensable ingredient for most aquatic animals. However, the finite supply and escalating price of fishmeal seriously limit its use in aquaculture. Thus the development of new, sustainable protein ingredients has been a research focus. Microalgae are potential fishmeal alternatives owing to their high protein content and balanced amino acid profile. Studies suggest that suitable replacement of fishmeal with microalgae is beneficial for fish growth performance, but excessive replacement would induce poor growth and feed utilization. Therefore, this paper aims to review research on the maximum substitutional level of fishmeal by microalgae and propose the main issues and possible solutions for fishmeal replacement by microalgae. The maximum replacement level is affected by microalgal species, fish feeding habits, quality of fishmeal and microalgal meals, and supplemental levels of fishmeal in the control group. Microalgae could generally replace 100%, 95%, 95%, 64.1%, 25.6%, and 18.6% fishmeal protein in diets of carp, shrimp, catfish, tilapia, marine fish, and salmon and trout, respectively. The main issues with fishmeal replacement using microalgae include low production and high production cost, poor digestibility, and anti-nutritional factors. Possible solutions to these problems are recommended in this paper. Overall, microalgae are promising fishmeal alternatives in aquaculture.

Microplastic (MP) toxicity has attracted widespread attention, whereas before triggering hepatotoxicity, ingested MPs first undergo transportation and digestion processes in the gastrointestinal tract, possibly interacting with the gastrointestinal contents (GIC). More alarming is the need for more understanding of how this process may impact the liver health of aged animals. This study selected old mice. Firstly, we incubated polystyrene microplastics (PS-MPs, 1 mu m) with GIC extract. The results of SEM/EDS indicated a structural alteration in PS-MPs. Additionally, impurities resembling corona, rich in heteroatoms (O, N, and S), were observed. This resulted in an enhanced aggregating phenomenon of MPs. We conducted a 10-day experiment exposing aged mice to four concentrations of PS-MPs, ranging from 1 x 103 to 1 x 1012 particles/L. Subsequent measurements of tissue pathology and body and organ weights were conducted, revealing alterations in liver structure. In the liver, 12 crucial metabolites were found by LC-MS technology, including purines, lipids, and amino acids. The AMPK/ FoxO pathway was enriched, activated, and validated in western blotting results. We also comprehensively examined the innate immune system, inflammatory factors, and oxidative stress indicators. The results indicated decreased C3 levels, stable C4 levels, inflammatory factors (IL-6 and IL-8), and antioxidant enzymes were increased to varying degrees. PS-MPs also caused DNA oxidative damage. These toxic effects exhibited a specific dose dependence. Overall, after the formation of the gastrointestinal corona, PS-MPs subsequently impact various cellular processes, such as cycle arrest (p21), leading to hepatic and health crises in the elderly. The presence of gastrointestinal coronas also underscores the MPs' morphology and characteristics, which should be distinguished after ingestion.

The study aimed to explore the effects of dietary guar gum supplementation on fish growth, histology, antioxidant capacity, and expression of inflammatory and apoptotic genes in juvenile largemouth bass (Micropterus salmoides) fed high-fat diets. Five isonitrogenous diets were prepared: a control diet (10% lipid, Control), a high-fat diet (18% lipid, HF), and three high-fat diets supplemented with 0.3%, 1%, and 3% guar gum (GG0.3, GG1, and GG3 respectively). Largemouth bass (3.11 +/- 0.01 g) were randomly assigned and fed for eight weeks. The results showed that dietary supplementation with 0.3% guar gum significantly increased final body weight, specific growth rate, and feed efficiency in comparison with HF (P < 0.05). For histology, high-fat diets containing guar gum significantly decreased vacuolated areas per hepatocyte and increased hepatic health status scores compared with HF (P < 0.05). Fish fed diets GG0.3 and GG1 exhibited lower malondialdehyde (MDA) contents (in the liver), higher reduced glutathione (GSH) contents (in plasma), and higher catalase (CAT) activity (in the liver) than those fed HF (P < 0.05). Furthermore, diets GG0.3 and GG1 significantly downregulated the expression of tumor necrosis factor alpha (TNF-alpha), cysteine-aspartic proteases 3 (Caspase 3), and Caspase 9 in the liver compared to HF (P < 0.05). These results suggest that guar gum can alleviate the adverse effects of high-fat diets on growth, antioxidant capacity, and hepatic health in fish.

This research aimed to determine the effect of dietary guar gum inclusion in high-lipid diets on the liver health of common carp (Cyprinus carpio). Four high-fat diets (10 % crude lipid) containing 0 % (HF), 0.3 % (HFG0.3), 1 % (HFG1), and 3 % (HFG3) of guar gum and a normal-lipid diet (5 % crude lipid; Control) were formulated. The tested diets were evenly and randomly distributed to fifteen tanks, with each tank containing thirty fish (4.53 +/- 0.05 g). Fish were fed until apparent satiation for eight weeks. Compared to HF, diets HFG0.3, HFG1, and HFG3 significantly improved feed efficiency, with the HFG0.3 diet enhancing weight gain rate and specific growth rate. The results indicated that HF induced gut dysbiosis, hepatic lipid accumulation, oxidative stress, inflammation, and disturbance in hepatic lipid and cholesterol metabolism. Compared to the HF diet, diets HFG0.3, HFG1, and HFG3 substantially decreased hepatic lipid accumulation and malonaldehyde content, increased catalase activity and the expression of AMP-activated protein kinase (AMPK alpha 2), peroxisomal proliferator-activated receptor alpha (PPAR alpha), cholesterol 7alpha-hydroxylase, and decreased the expression of interleukin-1 beta (IL-1 beta). Moreover, the HFG0.3 and HFG1 diets dramatically increased nuclear factor erythroid 2-related factor 2 and liver X receptor expression and decreased protein carbonyl contents and expression of IL-8, nuclear factor kappa B (NF-kappa B p65), and tumor necrosis factor alpha. Furthermore, the HFG1 diet significantly increased carnitine palmitoyltransferase 1 and peroxisomal proliferator-activated receptor gamma coactivator 1 expression and reduced expression levels of fibroblast growth factor 19, farnesoid X receptor, and sterol regulatory element-binding protein type 1. The linear discriminant analysis effect size (LEfSe) analysis showed that HFG 0.3 and HFG1 substantially increased the enrichment of beneficial microbiota (e.g., lactic acid bacteria, Cetobacterium, and Fusobacterial) and decreased the enrichment of harmful microbiota (e.g., Proteobacteria, Acinetobacter, and Pseudomonas) compared to HF. These results suggested that guar gum can mitigate high-fat diet-induced liver damage in fish.

To evaluate the effects of sodium butyrate (NaBT) supplementation in high-fat diets on the growth performance and liver health of common carp (Cyprinus carpio), we formulated three isonitrogenous diets: the control diet (5.8% crude lipid, Control diet), the high-fat diet (10.8% crude lipid, HF diet), and the NaBT diet (10.8 % crude lipid and 0.1% NaBT, NaBT diet). Each diet was assigned to triplicate tanks (100 L) with 24 fish (14.52 & PLUSMN;0.08 g) in each tank. Experimental fish were fed twice daily for 8 weeks. The results showed that fish growth performance was not affected by experimental diets. Fish at HF group demonstrated higher content of triacylglyceride (TG) and total cholesterol (TCHO) in the liver. In addition, diet HF significantly increased hepatic oxidative stress by increasing malondialdehyde (MDA) content, decreasing activity levels of antioxidant enzymes and contents of reduced glutathione (GSH). Furthermoure, diet HF significantly decreased the mRNA expression of nuclear factor erythroid 2-related factor 2 (Nrf2) and heme oxygenase-1 (HO-1), and simultaneously increased the mRNA expression of tumor necrosis factor & alpha; (TNF-& alpha;), interleukin-10 (IL-10), and IL-6 in liver of common carp compared to control diet (P<0.05). However, diet NaBT significantly improved fish liver health by decreasing contents of TCHO and MDA, down-regulating mRNA expression of pro-inflammatory cytokines (e.g., TNF-& alpha;, IL-10 and IL-6), increasing the activity levels of antioxidant enzymes, and upregulating the mRNA expression of Nrf2 and HO-1 in the liver (P<0.05). In conclusion, dietary NaBT supplementation could ameliorate the detrimental effects of high-fat diets on liver health by activating Nrf2 in common carp.

以青海省贵南县高寒草甸为例,通过设置不同放牧模式的试验,研究了冷地早熟禾(Poa crymophila)、青海薹草(Carex qinghaiensis)和鹅绒委陵菜(Potentilla anserine)叶片结构性状和功能性状对放牧的响应.结果表明:重度放牧导致青海薹草叶片干物质含量显著下降,对冷地早熟禾和鹅绒委陵菜没有影响;放牧导致青海薹草和鹅绒委陵菜的比叶面积显著升高;放牧导致3种牧草叶片碳含量显著降低,氮含量和磷含量显著升高,碳氮比、碳磷比和氮磷比也整体呈显著下降趋势.叶片性状对放牧响应的可塑性不同,叶片磷含量可塑性较强,是敏感性状,而叶片碳含量可塑性系数最低,为惰性性状,叶片干物质含量和比叶面积的变异性最大.总之,3种牧草叶片性状对放牧的响应模式不同,且与放牧模式有关.叶片表型性状的非对称变化是性状之间权衡的结果,可能是对放牧活动的一种适应策略.

The present study aimed to investigate the influence of guar gum supplementation in high-fat diets on the growth performance and intestinal oxidative stress, inflammation, and apoptosis of juvenile largemouth bass. Five isonitrogenous diets were prepared: a control diet (10% crude lipid, C), a high-fat diet (17% crude lipid, HF), and three high-fat diets supplemented with 0.3% guar gum (GG0.3), 1% guar gum (GG1), and 3% guar gum (GG3). Largemouth bass (3.1±0.2 g) were randomly assigned to fifteen tanks (30 fish/tank) and fed for 8 weeks. The results demonstrated that GG0.3 significantly increased specific growth rate (SGR) and increased feed conversion ratio (FCR) compared to HF (P < 0.05). For histology, high-fat diets containing guar gum significantly increased intestinal villus length, villus width, and perimeter ratio, compared with HF (P < 0.05). Compared with Control, HF significantly decreased reduced glutathione (GSH) contents and increased malondialdehyde (MDA) contents in the intestine (P < 0.05). Additionally, HF significantly increased the expression of interleukin 1β (IL-1β), tumor necrosis factor α (TNF-α), and cysteine-aspartic proteases 9 (Caspase 9) in the intestine (P < 0.05). Compared to HF, GG0.3 significantly decreased MDA contents, increased GSH contents, and downregulated the expression of IL-1β, TNF-α, and Caspase 3 than diet HF in the intestine (P < 0.05). These results suggest that guar gum can alleviate the adverse effects of high-fat diets on growth and gut health in fish.

OBJECTIVE The study aimed to evaluate the effects of phosphorus (P) deficiency in diets on growth performance, hepatic lipid metabolism, and antioxidant capacity in Yellow River Carp Cyprinus carpio haematopterus. METHODS In this study, 72 healthy experimental fish (initial weight = 12.0 ± 0.1 g [mean ± SE]) were randomly selected and distributed to two groups, with three replicates in each group. The groups were fed either a P-sufficient diet or a P-deficient diet for 8 weeks. RESULT The P-deficient feed significantly decreased the specific growth rate, feed efficiency, and condition factor of Yellow River Carp. Fish that were fed the P-deficient feed demonstrated higher contents of triglyceride, total cholesterol (T-CHO), and low-density lipoprotein cholesterol in the plasma and a higher T-CHO content in the liver compared to the P-sufficient diet group. In addition, the P-deficient diet significantly reduced the catalase activity level, decreased the glutathione content, and increased the malondialdehyde content in the liver and in the plasma. Furthermore, P deficiency in the diet significantly downregulated the messenger RNA expression of nuclear erythroid 2-related factor 2 and peroxisome proliferator-activated receptor α, whereas it upregulated the messenger RNA expression of tumor necrosis factor α and fatty acid synthase in the liver. CONCLUSION Dietary P deficiency reduced fish growth performance, induced fat deposition and oxidative stress, and impaired liver health.

以青海省贵南县高寒草甸为研究对象,采用地上植被调查和室内萌发试验相结合的方法,对不同放牧强度下土壤种子库的特征及其与地上植被的关系进行研究,并探讨放牧条件下地上植被、土壤种子库和土壤理化性质三者的联系,拟为高寒地区的植被恢复和草地管理提供科学参考.结果表明:1)随放牧强度的增加,土壤种子库密度呈现出"单驼峰"型趋势.2)无论是禁牧还是放牧样地,种子主要集中于 0-5 cm表层土壤,且随土层的加深而减少.3)高寒草甸土壤种子库与地上植被的相似性整体较低,在中度放牧样地中杂类草占主导地位,群落物种多样性增加,相似性相对较高;在禁牧样地中种群趋于平衡且枯落层较厚,相似性最低.4)放牧干扰后,植物群落高度整体降低,地上植被盖度增加,种子库的密度增大;且较低的磷含量有利于种子的储存.综上,高寒草甸适度的放牧干扰有利于维持草地群落的物种多样性,提高种子库种子的储存,从而促进地上植被的更新建植,进而维持草地生态系统稳定.

The study aimed to investigate the effect of Cu exposure (0, 51.3, 164, 513, 1,640, and 5,130 μg/L) on fish growth performance, histology, oxidative stress, inflammation, and apoptosis in largemouth bass ( Micropterus salmoides ) juveniles. 270 fish (2.69 ± 0.02 g) were randomly divided into 6 groups of tanks for 4 weeks with each group comprising three replicate tanks. The results showed that fish exposed to 1,640 and 5,130 μg/L Cu exhibited a significant reduction in fish growth and survival rate ( P < 0.05). Compared to the control, the fish at and above 513 μg/L Cu demonstrated histopathological damages in the gills and liver, such as shorter primary and secondary lamellae, smaller hepatocyte nuclei, and an increase in the number of necrotic cells in the liver. Compared to the control, fish at and above 1,640 μg/L Cu had a significantly higher malondialdehyde content and lower activity levels of total superoxide dismutase, glutathione peroxidase, and catalase in the gills and liver ( P < 0.05). Furthermore, high concentrations of Cu (1,640 and 5,130 μg/L) significantly increased hepatic inflammation by upregulating interleukin-1β and tumor necrosis factor α expression and hepatic apoptosis by increasing cysteinyl aspartate specific protease 3 (caspase-3) and caspase-9 expression ( P < 0.05). Pearson correlation analysis showed that fish growth and survival positively correlated with histological and antioxidant defense parameters, and negatively correlated with oxidative stress parameters, hepatic inflammation, and hepatic apoptosis. Taken together, these results suggest that high levels of waterborne Cu can induce growth retardation and mortality by damaging the liver and gill health.