Rapid loss of lampricide from catfish and rainbow trout following routine treatment

Rainbow trout (Oncorhynchus mykiss) and channel catfish (Ictalurus punctatus) were exposed to 3-trifluoromethyl-4-nitrophenol (TFM) and Bayluscide (niclosamide) during a sea lamprey control treatment of the Ford River, located in the upper peninsula of Michigan. Caged fish were exposed to a nominal concentration of 0.02 mg/L of niclosamide for a period of approximately 12 h. Samples of fillet tissue were collected from each fish species before treatment and at 6, 12, 18, 24, 48, 96, and 192 h following the arrival of the block of chemical at the exposure site. The fish were dissected, homogenized, extracted, and analyzed by high-performance liquid chromatography. The major residues found in the fillet tissues were TFM and niclosamide. Niclosamide concentrations were highest 12 h after arrival of the chemical block for rainbow trout (0.0395 +/- 0.0251 microg/g) and 18 h after arrival of the chemical block for channel catfish (0.0465 +/- 0.0212 microg/g). Residues decreased rapidly after the block of lampricide had passed and were below the detection limits in fillets of rainbow trout within 24 h and channel catfish within 96 h after the arrival of the lampricide.     

Determination of niclosamide residues in rainbow trout (Oncorhynchus mykiss) and channel catfish (Ictalurus punctatus) fillet tissue by high-performance liquid chromatography

Bayluscide [the ethanolamine salt of niclosamide (NIC)] is a registered piscicide used in combination with 3-(trifluoromethyl)-4-nitrophenol (TFM) to control sea lamprey populations in streams tributary to the Great Lakes. A high-performance liquid chromatography (HPLC) method was developed for the determination of NIC residues in muscle fillet tissues of fish exposed to NIC and TFM during sea lamprey control treatments. NIC was extracted from fortified channel catfish and rainbow trout fillet tissue with a series of acetone extractions and cleaned up on C(18) solid-phase extraction cartridges. NIC concentrations were determined by HPLC with detection at 360 and 335 nm for rainbow trout and catfish, respectively. Recovery of NIC from rainbow trout (n = 7) fortified at 0.04 microg/g was 77 +/- 6.5% and from channel catfish (n = 7) fortified at 0.02 microg/g was 113 +/- 11%. NIC detection limit was 0.0107 microg/g for rainbow trout and 0.0063 microg/g for catfish. Percent recovery of incurred radioactive residues by this method from catfish exposed to [(14)C]NIC was 89.3 +/- 4.1%. Percent recoveries of NIC from fortified storage stability tissue samples for rainbow trout (n = 3) analyzed at 5 and 7.5 month periods were 78 +/- 5.1 and 68 +/- 2.4%, respectively. Percent recoveries of NIC from fortified storage stability tissue samples for channel catfish (n = 3) analyzed at 5 and 7.5 month periods were 88 +/- 13 and 76 +/- 21%, respectively.     

Residues of the lampricides 3-trifluoromethyl-4-nitrophenol and niclosamide in muscle tissue of rainbow trout

Rainbow trout (Oncorhyncus mykiss) were exposed to the (14)C-labeled lampricide 3-trifluoromethyl-4-nitrophenol (TFM) (2.1 mg/L) or niclosamide (0.055 mg/L) in an aerated static water bath for 24 h. Fish were sacrificed immediately after exposure. Subsamples of skin-on muscle tissue were analyzed for residues of the lampricides. The primary residues in muscle tissue from fish exposed to TFM were parent TFM (1.08 +/- 0.82 nmol/g) and TFM-glucuronide (0.44 +/- 0.24 nmol/g). Muscle tissue from fish exposed to niclosamide contained niclosamide (1.42 +/- 0.51 nmol/g), niclosamide-glucuronide (0.0644 +/- 0.0276 nmol/g), and a metabolite not previously reported, niclosamide sulfate ester (1.12 +/- 0.33 nmol/g).     

Dissipation of teflubenzuron and triflumuron residues in field-sprayed and cold-stored pears.

Dissipation of residues of benzoylurea insecticides teflubenzuron (TFB) and triflumuron (TFM) under field conditions was evaluated on a pear orchard in Greece. Residues were determined by UV-HPLC analysis, with a detection limit of 0.030 mg/kg for both pesticides. TFB residues in pears were found to persist for 2 weeks and decline thereafter with 48% of the initial deposit remaining 42 days after the last application. TFM residues were found to decline following first-order kinetics and with a half-life of 39(+/-7) days. Residues of both pesticides found in pears collected at harvest maturity were lower than the maximum residue limits (MRLs) set by individual countries. Dissipation of TFB and TFM in cold-stored pears was also evaluated. TFB residues were very persistent for the whole storage period, whereas TFM residues did not dissipate for 6 weeks and then showed a constant decline; 7% of the initial concentration remained at the end of the storage period of 29 weeks.     

Demographic analysis of trade-offs with deliberate fragmentation of streams: Control of invasive species versus protection of native species

Tools restricting the movements of invasive species (e.g. barriers) and reducing habitat fragmentation for native species (e.g. corridors, fishways) provide examples where actions taken to address one environmental concern can hinder efforts to address another environmental concern. We used perturbation analysis of stage-structured projection matrices to evaluate the efficacy of seasonally operated barriers and fishways for controlling non-native sea lamprey (Petromyzon marinus) in the Laurentian Great Lakes while minimizing effects on non-target fishes. For non-jumping fishes migrating in spring, seasonally operated barriers without a fishway will not balance the management objectives satisfactorily. Migration phenologies of the seven common non-target fishes considered in our analyses overlapped considerably with the migration phenology of sea lamprey, with peaks in migration typically being 7–43 days (median 12) from the peak in the sea lamprey migration. Consequently, across species, years, and tributaries, 44–100% of the migratory runs of non-target fishes would be blocked under the 75-day operation period required to block 99% of the sea lamprey spawning run, on average. Reductions in the production of non-target fishes due to blocking were also projected to be similar in magnitude to reductions projected in the production of sea lamprey, unless density-dependent compensation was strong or overlap in migration phenologies between a non-target species and sea lamprey was low. Even under density-dependent compensation, providing a fishway is advisable and passage of non-target fishes may have to be highly effective to avoid population declines in non-jumping species that migrate between a Great Lake and its tributaries.     

Quantitative and confirmatory analyses of malachite green and leucomalachite green residues in fish and shrimp

Liquid chromatographic methods are presented for the quantitative and confirmatory determination of malachite green (MG) and leucomalachite green (LMG) for channel catfish, rainbow trout, tilapia, basa, Atlantic salmon, and tiger shrimp. Residues were extracted from tissues with ammonium acetate buffer and acetonitrile and isolated by partitioning into dichloromethane. LMG was quantitatively oxidized to the chromic MG with 2,3-dichloro-5,6-dicyano-1,4-benzoquinone. Extracts were analyzed for total MG by liquid chromatography with both visible detection (LC-VIS) at 618 nm for routine screening and ion trap mass spectrometry (LC-MSn) with no discharge-atmospheric pressure chemical ionization for residue confirmation. The method was validated in each species fortified with LMG at 1, 2, 4, and 10 ng/g (ppb), and average recoveries ranged from 85.9 to 93.9%. Quantitative data were consistent for the two detection methods, with measured method detection limits of 1.0 ng/g for LC-VIS and 0.25 ng/g for LC-MSn. Incurred tissues from catfish, trout, tilapia, and salmon that had been treated with MG were also extracted and analyzed as part of this study.     

Residue depletion of nitrofuran drugs and their tissue-bound metabolites in channel catfish (Ictalurus punctatus) after oral dosing

The depletion of the nitrofuran drugs furazolidone, nitrofurazone, furaltadone, and nitrofurantoin and their tissue-bound metabolites [3-amino-2-oxazolidinone (AOZ), semicarbazide (SC), 3-amino-5-morpholinomethyl-2-oxazolidinone (AMOZ), and 1-aminohydantoin (AH), respectively] were examined in the muscle of channel catfish following oral dosing (1 mg/kg body weight). Parent drugs were measurable in muscle within 2 h. Peak levels were found at 4 h for furazolidone (30.4 ng/g) and at 12 h for nitrofurazone, furaltadone, and nitrofurantoin (104, 35.2, and 9.8 ng/g respectively). Parent drugs were rapidly eliminated from muscle, and tissue concentrations fell below the limit of detection (1 ng/g) at 96 h. Peak levels of tissue-bound AMOZ and AOZ (46.8 and 33.7 ng/g respectively) were measured at 12 h, and of SC and AH (31.1 and 9.1 ng/g, respectively) at 24 h. Tissue-bound metabolites were measurable for up to 56 days postdose. These results support the use of tissue-bound metabolites as target analytes for monitoring nitrofuran drugs in channel catfish.     

Bacillus stearothermophilus disk assay for determining ampicillin residues in fish muscle.

The Bacillus stearothermophilus disk assay for penicillin in milk (AOAC official method) was adapted for the determination of ampicillin in fish muscle. The method was evaluated in 2 species of cultured fish: channel catfish and striped bass. Recoveries of ampicillin ranged from 99 to 104% when muscle specimens from both species were spiked at concentrations of 0.025-1.00 micrograms/g. The lower limit of determination (LOD) was 0.025 micrograms/g. The assay was applied to monitor the elimination of ampicillin from the muscle of striped bass after intravascular administration (dosage of 10 mg/kg body weight). The mean concentrations in the muscle declined from 1.160 micrograms/g at 2 h to 0.063 micrograms/g at 18 h. The half-life of ampicillin in the muscle was 3.6 h. Ampicillin concentrations were below LOD at 24 h. No inhibitory activity was observed in the muscle of control fish.     

Polybrominated diphenyl ethers in retail fish and shellfish samples purchased from Canadian markets

Fish and shellfish retail samples (n = 122) were purchased from three Canadian cities in the winter of 2002 and analyzed for a total of 18 polybrominated diphenyl ether (PBDE) congeners. The samples (salmon, trout, tilapia, Arctic char, mussels, oysters, shrimp, and crab) represented the range of fish and shellfish commercially available to Canadian consumers at the time of purchase. Trout and salmon (geometric mean SigmaPBDE = 1600 and 1500 pg/g, wet weight, respectively) were found to contain significantly higher amounts of PBDEs than the mussel, tilapia, and shrimp groups (geometric mean SigmaPBDE = 260, 180, and 48 pg/g, wet weight, respectively). These differences in SigmaPBDE concentrations among fish and shellfish products were partly driven by differences in lipid content among the samples. Mean SigmaPBDE concentrations in domestic samples were also significantly greater than in imported samples, possibly reflecting global environmental distribution of PBDEs. These concentration differences will contribute to variations in dietary exposure to PBDEs when assorted fish and shellfish items from various origins are consumed.     

Chemical composition of effluent from high density culture of channel catfish

Production rates of metabolic wastes by channel catfish (Ictalurus punctutas) were estimated by analyzing effluents from high density culture of 940 g and 60 g catfish. Results were integrated over a 24 h steady-state period in which normal feeding activities were maintained and were expressed as g day^?1kg^?1 fish and g day^?1 kg^?1 feed consumed. When expressed on a unit fish weight basis, production rates were greater for 60 g than for 940 g catfish. However, when expressed on a feed consumption basis, production rates of most catabolic products were approximately equal for both size fish. Average values (g day^?1 kg^?1 feed) were as follows: total N, 67; ammonia N, 20; nitrate-nitrite N, 20; 5-day BOD, 98; total solids, 180; total P, 15; total K, 18. Filtered solids from effluent contained 5% nitrogen, 1.6% phosphorus and .13%. potassium. Diurnal variation in production rates were noted with solid production reaching a maximum after each feeding and BOD, NH₃ and nitrate reaching a maximum only in the afternoon.     

The toxic mixing zone of neutral and acidic river water: Acute aluminium toxicity in brown trout (Salmo trutta L.)

Mixing of acid river water containing aluminium (pH 5.1, Al 345 g.l^–1) with neutral water of a lake (pH 7.0, Al 73 g.l^–1) resulted in water (pH 6.4, Al 245 g.l^–1) with a pH (6.4) and Al concentration (245 g.l^–1) expected to have low toxicity to fish on the basis of current Al toxicity models. However, under semi-field conditions the freshly mixed water (a few sec. after mixing) proved to be highly toxic to brown trout. The fish were exposed to the water at different places along a 30 m channel. At the beginning of the channel acid and neutral water were continuously mixed; the mixed water left the channel after 340 sec. The cells of the gills showed a highly increased rate of cell death by apoptosis and necrosis. Intercellular spaces were enlarged, and many leucocytes penetrated in these spaces. Mucus release was stimulated to depletion. Plasma chloride levels were hardly affected. There was a clear gradient in the deleterious effects on the fish along the channel. The fish at the beginning of the channel (about 12 sec. after mixing of the water), were severely affected, whereas the fish kept at the end of the channel (340 sec. after mixing) were only mildly affected. In the natural situation fish will relatively quickly pass through a mixing zone. In our study we therefore focused on the effects on fish after a 60 min exposure to a mixing zone (5 sec after mixing), with subsequent recovery in a region downstream of the confluence and in neutral water with low Al. The recovery in the downstream area (at the end of the channel, i.e. 5 min after mixing) was clearly hampered when compared to the recovery in neutral water with low aluminium. Thus, a short exposure to the toxic mixing zone followed by a stay in water downstream of this zone, as may occur in nature, is detrimental to migrating trout. We conclude that freshly mixed acid and neutral water contain toxic components during the first seconds to minutes after mixing, that can not be explained by current models on aluminium toxicity.     

Microbiological transformation of carbon and nitrogen compounds in forest soils of Central Evenkia

It has been found that the total productivity of bacteria and micromycetes in the 0- to 50-cm layer of homogeneous cryozems (Cryosols) on slopes of northern and southern exposures varies from 1.2 to 1.4 t/ha, respectively, and the calculated content of microbial carbon varies in the range 0.7–0.9 t/ha. The respiratory activity of the upper soil layer is 2.5–2.6 μg C–CO₂/(g h); the potential methane formation capacity reaches 0.13 nmol CH₄/(m² day) for soils on slopes of northern exposure and 0.16 nmol CH₄/(m² day) for slopes of southern exposure. Accumulation of sorbed ammonium is recorded in the range 15–17 mg NH₄/100 g soil in summer. The increase of temperature in the upper horizons of soils on slopes of southern exposure by 5°C compared to the northern slopes results in only an insignificant increase in the emission of CO₂ and CH₄. The accumulation of sorbed ammonium and nitrate nitrogen in homogeneous cryozems during the vegetation period is comparable to that in gray forest soils of the southern taiga subzone of the Middle Siberia.     

Liquid chromatographic analysis of incurred amoxicillin residues in catfish muscle following oral administration of the drug

Improper application of antibiotic chemicals to livestock and aquaculture species may lead to the occurrence of residues in food supplies. An appropriate depletion period is needed after the administration of drugs to animals for ensuring that residues in edible tissues are below established tolerance levels. This study was conducted to determine incurred amoxicillin residues in catfish muscle following oral administration. Dosed fish were harvested after four depletion periods, and muscle fillets were analyzed for amoxicillin residues using an HPLC method with precolumn derivatization and fluorescence detection. The residue levels in fish after a 6-h depletion ranged from 40 to 64 ng/g with one exception at 297 ng/g. Average residue levels decreased to 5.4 and 2. 8 ng/g after 24- and 48-h depletions, respectively. Residue levels after a 72-h depletion decreased to below the method's limit of quantitation (1.2 ng/g). An LC-MS/MS confirmatory method was developed. Confirmation of the presence of amoxicillin was demonstrated in incurred fish samples containing residues at approximately 50-300 ng/g.     

Uniformly (14)C-ring-labeled 2,4-dichlorophenoxyacetic acid: a metabolism study in bluegill sunfish, Lepomis macrochirus.

The fate of 2,4-dichlorophenoxyacetic acid (2,4-D), a mixture of [phenyl(U)-(14)C]-2,4-D and unlabeled 2,4-D, in bluegill sunfish was investigated after exposure to approximately 11 ppm under static conditions for 4 days. Total radioactive residues (TRR) in whole fish increased from 0.41 ppm on day 1 to 0.60 ppm on day 3. TRR levels in fillet (edible) and viscera (nonedible) of treated fish on day 4 were 0.41 and 1.9 ppm, respectively. Most residues in both matrices were acetonitrile soluble; small amounts were hexane soluble or unextractable with solvents. Acid and base hydrolyses with ethyl acetate partitioning were used to release the fillet unextractable residues. The identification of 2,4-D and 2,4-dichlorophenol (2,4-DCP) in the fillet was conclusively confirmed by GC-MS analysis. On the basis of the experimental data from this study, a metabolic pathway for 2,4-D in bluegill sunfish in which the 2,4-D is metabolized to 2,4-DCP and conjugates of 2,4-D and 2,4-DCP is proposed.     

Type of organic carbon amendment influences pH changes in acid sulfate soils in flooded and dry conditions

Purpose

Acid sulfate soils (ASS) are common in wetlands and can pose an environmental threat when they dry because oxidation of pyrite may cause strong acidification. Addition of organic matter can stimulate sulfate reduction during wet periods and minimize acidification during dry periods. However, the effect of the organic amendment may depend on its composition.

Materials and methods

Three wetland acid sulfate (sulfuric, hypersulfidic, and hyposulfidic) soils collected from different depth in one profile were used. The soils, unamended or amended with 10 g C kg^?1 as glucose, wheat straw, pea straw, or Phragmites litter, were incubated for 18 weeks under flooded conditions (“wet period”) followed by 10 weeks during which the soils were maintained at 100 % of maximum water-holding capacity (“dry period”).

Results and discussion

During the wet period, the pH decreased in the control and with glucose to pH 3–4, but increased or was maintained in residue-amended soils (pH at the end of the wet period about 7). In the dry period, the pH of the control and glucose-amended soils remained low, whereas the pH in residue-amended soils decreased. However, at end of the dry period, the pH was higher in residue-amended soils than in the control or glucose-amended soils, particularly with pea straw (C/N 50).

Conclusions

Amendment of acid sulfate soils with plant residues (particularly those with low to moderate C/N ratio) can stimulate pH increase during flooding and reduce acidification under oxidizing conditions.

     

Short‐term effects of manganese toxicity on ribulose 1,5 bisphosphate carboxylase in tobacco chloroplasts

The short‐term effects of manganese (Mn) toxicity on ribulose 1,5 bisphosphate carboxylase EC 4.1.1.39 (Rubisco) activity and concentration in tobacco (Nicotiana tabacum L. ‘KY 17') chloroplasts were examined. The activity of the enzyme from both Mn‐treated and control plants was determined 6,12,18, 24, and 48 h after introduction of Mn (80 mg/L). Enzyme activity was determined by monitoring rates of carbon dioxide (¹⁴CO₂) fixation into acid stable products. A decrease in the enzyme's activity in experimental plants was noted after 48 h of exposure. Visible symptoms, such as chlorosis and decreased leaf size, were also observed after 48 h of Mn exposure in experimental plants. Using Rocket Immunoelectrophoresis, no appreciable differences between Rubisco concentration levels of the experimental plants and the control plants were noted indicating that the effect on Rubisco activity is a post‐translational phenomenon and that Rubisco is not being degraded at an accelerated rate. Manganese accumulated in the experimental plants to concentrations as high as 3282 μg/g dry wt as determined by atomic absorption spectrophotometry. A shuttling mechanism for Mn between young and old leaves was indicated by an observed decrease in the concentration of Mn in the young leaf tissue between 12 and 18 h after treatment.     

Quantification of phosphatidic acid in foodstuffs using a thin-layer-chromatography-imaging technique

Apical application of lysophosphatidic acid (LPA), a growth-factor-like phospholipid, was shown to prevent or restore gastrointestinal (GI) disorders, such as diarrhea and stomach ulcer, in experimental animals. Because LPA is formed from phosphatidic acid (PA) by the activity of digestive phospholipase A(2), PA is a potential component for dietary treatment of such GI disorders. Here, we quantified PA contained in 38 foodstuffs and 3 herbs by a thin-layer-chromatography-imaging technique. Vegetables belonging to Brassicaceae, such as cabbage leaves (700 nmol/g of wet weight) and Japanese radish leaves (570 nmol/g), contained higher amounts of PA than other foodstuffs. Amounts of PA in fruits, cereals, and starchy root vegetables were below 300 nmol/g. Animal foodstuffs contained low amounts of PA (<60 nmol/g). Interestingly, leaves of Mallotus japonicas, a Japanese edible herb used for treatment of stomach ulcer, had the highest PA (1410 nmol/g) among those examined. The data shown here will be useful for the development of dietary treatment for a damaged GI tract.     

基于LF-NMR研究包装方式和温度对鲶鱼片保水性的影响

为了考察贮藏过程中包装方式和温度对鲶鱼片保水性的影响,该试验将新鲜鲶鱼片分别经空气包装(air-package,AP)、真空包装(vacuum package,VP)和气调包装(modified atmosphere package,MAP,60%CO_2+40%N_2)后贮藏于4℃和-0.7℃的冷库中,于贮藏第0、1、4、7、10、15、20、30天测定鲶鱼片的pH值、蒸煮损失率、离心失水率等指标变化,利用低场核磁共振(low-field nuclear magnetic resonance,LF-NMR)技术测定鲶鱼片的水分弛豫时间(T22)、弛豫面积(P22)和质子密度成像(magnetic resonance imaging,MRI),并利用扫描电镜(scanning electron microscopy,SEM)观察鲶鱼片肌纤维结构的变化,对鲶鱼片贮藏过程中保水性变化及原因进行综合判断。结果显示,随着贮藏时间的延长,各组鲶鱼片保水性均呈下降趋势,表现为蒸煮损失率和离心失水率比新鲜鲶鱼片增加,弛豫时间T22和弛豫面积P22降低。相比较而言,冰温气调(-0.7°C-MAP)样品的保水性下降最为缓慢,是鲶鱼片品质保持的较佳贮藏方法。皮尔逊相关系数分析表明弛豫面积P22与贮藏时间、蒸煮损失率及离心失水率显著相关(P0.05);MRI结果显示,鲶鱼片的水分在贮藏过程中逐渐从肌纤维内部渗出,集聚在肌束膜上;SEM表明肌纤维细胞结构发生改变,这可能是引起保水性下降的根本原因。综上所述,该研究证明利用LF-NMR技术可快速表征鲶鱼肉保水性的变化,研究结果为选择鲶鱼片的较佳贮藏条件提供了理论依据。     

Quantitation of dityrosine in wheat flour and dough by liquid chromatography-tandem mass spectrometry

A method for the quantitation of dityrosine in wheat flour and dough by high-performance liquid chromatography/tandem mass spectrometry (HPLC-MS/MS) using an isotope dilution assay with the internal standard 3,3'-(13)C(2)-dityrosine in the single-reaction monitoring mode was developed. The method consisted of the release of protein-bound dityrosine by hydrolysis in 4 mol/L hydrochloric acid/8.9 mol/L propionic acid for 24 h at 110 degrees C after addition of the internal standard, cleanup by C(18) solid-phase extraction, and HPLC-MS/MS. The limit of detection of dityrosine was 80 ng/g of sample (0.22 nmol/g), and the limit of quantitation was 270 ng/g of sample (0.75 nmol/g). The method was sensitive enough to analyze wheat flour and dough and to study the effect of flour improvers on the dityrosine content. Furthermore, the effect of the mixing time was studied. The dityrosine concentration in the flour was 0.66 nmol/g. After we mixed a dough to peak consistency, the dityrosine concentration doubled and remained constant on further mixing. Overdoses of hydrogen peroxide and hexose oxidase (HOX, E.C. 1.1.3.5) resulted in a strongly increased dityrosine content, whereas no increase of the dityrosine concentration was found after the addition of ascorbic acid and potassium bromate. Calculation of the percentage of dimeric tyrosine showed that less than 0.1% of the tyrosine residues of wheat protein were cross-linked. Therefore, dityrosine residues seem to play only a very minor role in the structure of wheat gluten.     

Protective Roles of Calcium Channel Blocker Against Cadmium-Induced Physiological Stress in Freshwater Teleost Oncorhynchus mykiss

The roles of verapamil (VRP), a calcium channel blocker, on cadmium-induced physiological stress in freshwater teleost Oncorhynchus mykiss were investigated in this study. Forty-eight juvenile rainbow trout were divided randomly into four groups, i.e., control group, VRP group (100 μg/L VRP), Cd group (50 μg/L Cd²⁺), and VRP?+?Cd group (100 μg/L VRP?+?50 μg/L Cd²⁺). After 1-week exposure, oxidative stress indices (lipid peroxidation and carbonyl protein) and antioxidant parameters (superoxide dismutase, glutathione reductase, glutathione peroxidase, and reduced glutathione) were measured in gill and liver of all tested fish. Additionally, the behavioral changes were recorded during the experimental period. Compared with the control, cadmium-induced stress was apparent as reflected by a serious oxidative stress in gill and liver tissues, inhibited branchial antioxidant parameters, and induced hepatic antioxidant responses, as well as abnormal behaviors observed. In the VRP?+?Cd group, the antioxidant defense system of fish returned to the control level, and the fish behavioral abnormalism markedly decreased. The present results suggested that VRP could reduce the cadmium-induced physiological stress in rainbow trout and provided further evidence that Cd²⁺ uptake through Ca²⁺ transport pathways in freshwater teleost.