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To explore the differences in the nutritional quality of the muscles of bighead carp from different environments and aquaculture systems, we investigated three types of water bodies typically used for aquaculture: A common culture pond (NC), a natural lake (PY), and a cold water reservoir (XHK). Parameters affecting quality were evaluated, including muscle microstructure, fatty acid profiles, amino acid profiles, and volatile compounds. Fish from the XHK reservoir had the smallest muscle fiber diameter and the highest muscle fiber density (25.3 fibers/0.01 mm2), while muscle fiber density was lowest in fish from the NC pond (9.7 fibers/0.01 mm2). The bighead carp from the XHK reservoir had a much wider variety of unsaturated fatty acids, as well as higher levels of total polyunsaturated fatty acids. Eicosapentaenoic acid (EPA), docosahexenoic acid (DHA), and arachidonic acid (AA) were all significantly more abundant in the XHK group, increases of 7.48%, 12.12%, and 17.49%, respectively (P

Nonsteroidal anti-inflammatory drugs (NSAIDs) have been widely detected in wastewater and surface water, indicating that the removal of NSAIDs by wastewater treatment plants was not efficient. Electrochemical advanced oxidation technology is considered to be an effective process. This study presents an investigation of the kinetics, mechanism, and influencing factors of diclofenac (DCF) degradation by an electrochemical process with boron-doped diamond anodes. Relative operating parameters and water quality parameters are examined. It appears that the degradation follows the pseudo-first-order degradation kinetics. DCF degradation was accelerated with the increase of pH from 6 to 10. The degradation was promoted by the addition of electrolyte concentrations and current density. Humic acid and bicarbonate significantly inhibited the degradation, whereas chloride accelerated it. According to the quenching tests, hydroxyl radicals (•OH) and sulfate radicals contributed 76.5% and 6.5%, respectively, to the degradation. Sodium sulfate remains a more effective electrolyte, compared to sodium nitrate and sodium phosphate, suggesting the quenching effect of nitrate and phosphate on •OH. Major DCF transformation products were identified. According to the degradation products detected by liquid chromatography–mass spectrometry, hydroxylation and decarboxylation are the main pathways of DCF degradation; while dechlorination, chlorination, and nitro substitution are also included in this electrochemical degradation process. Highlights The electrochemical degradation of DCF at BDD anodes follows pseudo-first-order kinetics.; •OH contributes more than SO4•–, but the effect of SO4•– cannot be ignored.; The presence of Cl− significantly accelerated the degradation of DCF.; Hydroxylation and decarboxylation are main pathways in DCF degradation.

The object of this work is to investigate the effects of emodin and curcumin on Pengze crucian carp. Fish was, respectively, fed Control diet and supplementation of 50 mg/kg emodin (EM group) and curcumin (CU group) with 4 repetitions each group (20 fish per cage). Our results indicated that the growth was unaffected by diets, whilst whole‐body lipid content was detected to remarkably decrease in EM group. Two additives exerted positive impacts on antioxidant system through elevation of antioxidant enzymes activities and antioxidants content. The improvement of intestinal antioxidant property appeared to be associated with up‐regulating expression of antioxidant genes through nuclear factor erythroid 2‐related factor 2 (Nrf2) activation. Moreover, intestinal inflammatory response was suppressed in EM and CU groups through inhibition of Toll‐like 4 receptor (TLR4) signalling pathway and pro‐inflammatory cytokine genes expression, and it may be related to the regulation of antioxidant system and overexpression of interleukin‐10. Afterwards, intestinal barrier function was enhanced in EM and CU groups by inducing the expression of tight junction protein genes. These results revealed that emodin and curcumin exerted positive benefits on the health of Pengze crucian carp by enhancing antioxidant capacity, suppressing inflammatory response and improving intestinal barrier function.

Excessive use of plant protein can cause various diseases, and functional additives have been proven to improve the health of aquatic fish but its underlying mechanism is still unclear. A 60-day trial was conducted to explore the action mechanism of β-glucan (1 g/kg), inulin (1 g/kg) and emodin (0.1 g/kg) supplementation improving the health of grass carp (initial weight 27.19 ± 0.05 g) fed low fishmeal diet. Our results indicated that emodin exhibited a positive impact on the growth of grass carp. Diet with β-glucan, inulin and emodin displayed hepatoprotective effects through the suppression of activities of serum alanine aminotransferase, aspartate aminotransferase and γ‐glutamyl transaminase, and β-glucan and inulin exerted hypocholesterolemic effects simultaneously. High level of antioxidant parameters in serum and intestine tissue confirmed the antioxidant property of β-glucan, inulin and emodin on grass carp, companying by a notable reduction in malondialdehyde content. Modulation of antioxidant response by β-glucan, inulin and emodin supplementation was to activate Nrf2 signaling pathway and up-regulate the expression of antioxidant genes including catalase and copper/zinc superoxide dismutase. Additionally, TLR4 signaling pathway was notably inhibited by three additive diets, and the transcription level of pro-inflammatory cytokines like IL-1β, TNF-α, and/or IL-6 was dramatically suppressed in intestine tissue simultaneously. Afterward, an enhancement of intestinal barrier function was observed in fish fed β-glucan, inulin and emodin by inducing the overexpression of junction proteins such as Occludin, ZO3, ZO1, and/or ZO2. The above results documented that diet with β-glucan, inulin and emodin could exhibit beneficial impacts on the health of grass carp through the improvement in antioxidant capacity, suppression of inflammatory response, and enhancement of intestinal barrier function.

Phosphite is an important intermediate of the phosphorus cycle. Its life in environment is related to its oxidation rate. This paper investigated the photooxidation of phosphite in aqueous solution in the presence of ferric and oxalate ions under a Xe lamp. The photooxidation of phosphite followed pseudo-first-order reaction kinetics. The kinetics constant of 100 μmol L−1 phosphite was 0.0039 min−1 at pH 3 and Fe(III)/Ox 10.0/100.0 μmol L−1. The photooxidation was dependent upon the pH value, phosphite/ferric/oxalate concentration, and light intensity. The decrease of phosphite coincided with the increase of phosphate. The addition of 2-proponal, NaN3 or furfuryl alcohol inhibited the photooxidation of phosphite, which indicated that the yielded reactive oxygen species played an important role in the oxidation of phosphite. The results contribute not only to predict the longevity of phosphite in the aqueous solutions, but also to understand the transfer of phosphite in P cycle.

Phosphite, phosphate, glyphosate and aminomethylphosphonic acid (AMPA) in natural water were determined by two-dimensional ion chromatography system coupled with capillary ion chromatography (2D-CIC). After filtrated by a 0.22-μm filter membrane, 25 μL of samples was injected into the first dimensional analytical column (AS11-HC) for preliminary separation. According to the different retention times in the first dimension, the target ions were divided into two groups (one group was phosphite and phosphate, another group was glyphosate and AMPA), then switched to the second dimensional capillary column (MAX-100) for further separation and detection. The effluent flow rates were 0.38 mL min −1 in the first dimension and 0.01 mL min −1 in the second dimension with KOH gradient elution, respectively. The carbonate removal devices were employed. The external standard method was used in all instances to quantitatively analyze. The results showed that the detection limits ( S/N = 3) were 0.18 nM for phosphite, 0.073 nM for phosphate, 0.15 nM for glyphosate and 2.6 nM for AMPA. The relative standard deviations (RSD, n = 6) of peak area ranged from 2.7% to 4.6%. The recoveries ranged from 80.1% to 118.4%. The results demonstrated that coupled capillary system could afford the simple detection of trace materials in natural water with complex matrix.

The phototransformation of phosphite (HPO32−, H2PO3−, +3) from Lake Taihu water (THW) under natural sunlight was evaluated. No direct phosphite photoreaction was observed under sunlight. Suspended solids were shown to play important roles in the indirect photoreaction of phosphite in lake water. The phototransformation of phosphite followed pseudo-first-order reaction kinetics and the kinetics constants (k, d−1) decreased as: 0.0324 (original THW), 0.0236 (sterilized THW), 0.0109 (filtered THW) and 0.0102 (sterilized filtered THW). Original THW with 1 mmol L−1 NO3− added was used to simulate the phosphite removal in lakes with serious N pollution. The results showed that the phototransformation was accelerated (with k increased to 0.0386–0.0463 d−1), and sterilization or filtration shown little effect to the transformation, as the half-lives of phosphite drew closer. Under simulated irradiation in NO3− system, increasing NO3− concentration or decreasing pH value promoted phototransformation. The addition of Fe3+ or Fe2+ accelerated photooxidation, while the addition of Mn2+ or Cd2+ inhibited phototransformation. Br−, NO2− and HCO3− in environmental concentrations decreased phototransformation, and HCO3− showed the strongest inhibition. Suwannee River humic acid or Suwannee River fulvic acid strongly inhibited the photooxidation process, and the inhibiting effects varied with their structure. Phosphite photooxidation was strongly inhibited by adding isopropanol or sodium azide as reactive oxygen species (ROS) quenchers. Electron spin resonance analysis indicated that OH was a main oxidant produced in this system. The increased amount of phosphate coincided with the decreased amount of phosphite, which indicated that the transformation product of phosphite was phosphate. Phosphite is a considerable component of the P redox cycle in Lake Taihu.

Phosphite (H2PO3(-), HPO3(2-), +3 valence), a reduced form of phosphorus (P), has been widely detected in water environments. The role of phosphite in the P biogeochemical cycle has not been investigated systematically and quantitative results on phosphite fluxes are lacking. In this study, intact sediment core simulation was employed to measure the flux of phosphite at the sediment-water interface in northern Lake Taihu. Phosphite fluxes (μmol m(-2) d(-1)) ranged from -38.21±1.14 to 7.10±2.18, with an annual average of -4.72±10.40. On the whole, phosphite migrated from water into sediment and the sediment was primarily a sink. The highest seasonal negative phosphite fluxes (μmol m(-2) d(-1)) occurred in winter (-10.44±18.63), followed by summer (-8.04±5.61) and spring (-2.61±4.17). In autumn, phosphite flux was 2.20±4.07. Higher annual average negative fluxes of phosphite (μmol m(-2) d(-1)) appeared in site ZSB (-12.70±17.96), which contained the highest content of total soluble P. The average yearly migration of phosphite in Lake Taihu from water to sediment was estimated to be (4.04±8.88)×10(6) mol y(-1). The transfer of phosphite from water into sediment usually occurs in winter may due to the season's natural tendency to create more favorable conditions for phosphite biogeochemical reactions. Phosphite fluxes showed significant negative correlations with the original phosphite concentration in water (r=-0.840, p

Glyphosate may have dual effect on bloom algae as a phosphorus source or pesticide. The physiological and biochemical responses of Microcystis aeruginosa ( M. aeruginosa ) to glyphosate and its formulation in the common herbicide, Roundup ® , were compared. The result suggested that both the cell numbers and Chl- a content of M. aeruginosa increased when the glyphosate concentration increased from 0.01 to 5 mg P L −1 . However, Roundup ® showed low-dose (below 1 mg P L −1 ) stimulation and high-dose (above 1 mg P L −1 ) inhibition on M. aeruginosa cell density and Chl- a content (hormesis effect). Phosphate was more available than glyphosate or Roundup ® , and Roundup ® was more toxic than glyphosate itself at 3 mg P L −1 . Analysis of the maximum yield of PSII indicated that glyphosate stimulated the photosynthesis process while Roundup ® inhibited the photosynthesis of M. aeruginosa . The photosynthesis process was enhanced on the 21st day compared with that on the 14th day in all P mediums. The extracellular alkaline phosphatase activity (APA) decreased with the increasing glyphosate or Roundup ® concentration. The change pattern of APA was similar in both the glyphosate and Roundup ® mediums.