Toxicity of ammonia and nitrite to yellow catfish (Pelteobagrus fulvidraco)

The 96‐h LC₅₀ (median lethal concentration, LC₅₀) tests were conducted using four different sizes of yellow catfish Pelteobagrus fulvidraco to provide primary information on the sensitivity of this species to elevated ammonia and/or nitrite, and to determine if the sensitivity is mediated by size under the same conditions. The results showed that 96‐h LC₅₀ of fish weighing 0.034 ± 0.002, 0.296 ± 0.049, 3.52 ± 0.95 and 32.96 ± 5.75 g to total ammonia nitrogen‐N was 24.96, 35.85, 47.44 and 68.79 mg L^?1, respectively; un‐ionized ammonia nitrogen‐N was 0.34, 0.49, 0.65 and 0.94 mg L^?1 in test conditions of pH 7.42 and 23°C; and that nitrite nitrogen‐N was 69.06, 97.23, 133.61 and 196.05 mg L^?1 in test conditions of pH 7.58 and 23°C, respectively. The NOEL (No Observable Effect Level) of fish (body weight from 0.03 to 30 g) to ammonia and nitrite was 2.25–6.22 mg L^?1 total ammonia nitrogen‐N, 0.03–0.10 mg L^?1 un‐ionized ammonia nitrogen‐N in test conditions of pH 7.42 and 23°C, and 6.27–17.68 mg L^?1 nitrite nitrogen‐N in test conditions of pH 7.58 and 23°C, respectively. These results indicate that the susceptibility of this fish to total ammonia or nitrite was reduced with increasing size, and that a dose‐dependent relationship might exist between them. The 96‐h LC₅₀ and NOEL of different sizes of fish to total ammonia, un‐ionized ammonia and nitrite would be important to know for water quality standards in yellow catfish aquaculture.     

Ion flux and cortisol responses of cardinal tetra,Paracheirodon axelrodi (Schultz, 1956), to additives (tetracycline,tetracycline + salt or Amquel®) used during transportation: contributions to Amazonian ornamental fish trade

The cardinal tetra, Paracheirodon axelrodi (Schultz), is the most important ornamental fish exported from Brazil and Colombia. During the transport of this species, Amazon fishermen usually add unmeasured amounts of tetracycline and/or table salt to the water in an effort to mitigate stress and mortality. The aim of the present study was to analyze the effect of salt, the antibiotic tetracycline and the ammonia chelating agent Amquel^® in the transport of this species. Cardinal tetras were submitted to a 24‐h boat transport in water containing either tetracycline hydrochloride (2.5 mg L^?1), Amquel^® (26.41 mg L^?1), tetracycline + table salt (2.5 mg L^?1 + 66.67 mg L^?1), or additive‐free water (control treatment). Whole‐body cortisol measurements showed that fish transported with any water additive had lower cortisol levels compared to control. However, based on ionoregulatory and water quality parameters, the addition of tetracycline, Amquel^® or the combination tetracycline + salt to the water of transport of cardinal tetras is not recommended when compared to control. Although Amquel^® helped stabilize the pH and diminish total ammonia levels in the transport water, this compound dramatically increased net Na⁺ and Cl^? uptake, and therefore compromised cardinal tetra ionoregulation.     

Effects of temperature on growth,hematology, and immune responses of subadult Chinese sturgeon (Acipenser sinensis Gray 1835) under different ammonia nitrogen conditions in recirculating aquaculture system

The growth, hematology, and immune responses of subadult Chinese sturgeon (Acipenser sinensis) (avg. wt. 25.11 ± 3.74 kg) were determined at three water temperature levels (12, 18, and 24°C) × three concentrations of total ammonia nitrogen (TAN) (0.05 ± 0.02, 1.03 ± 0.04, and 2.03 ± 0.05 mg/L) for 90 days in recirculating aquaculture system (RAS). At the end of the experiment, all fish were weighed and serum was collected for analysis using biochemical parameters. The temperature level had significant effects on the growth and hematology responses of subadult Chinese sturgeon under the RAS conditions. The specific growth rate (SGR) of subadult Chinese sturgeon was highest at 18°C compared to other temperatures; at this temperature, the total antioxidant capacity (T‐AOC), alanine aminotransferase (ALT) and lysozyme (LZM) activities were also the highest (p < 0.05). As the temperature rose, the oxygen consumption rate and ammonia excretion rates significantly increased (p < 0.05). In addition, there was no effect of TAN level on ammonia excretion rates of subadult Chinese sturgeon, while the oxygen consumption rate was greater in the high TAN group compared with the other groups (p < 0.05). The SGR of the fish was markedly reduced when the TAN level rose, and blood urea nitrogen (BUN), blood ammonia (BA), malondialdehyde (MDA) and cortisol in the serum were significantly elevated when the fish were in high TAN water for 90 days (p < 0.05), T‐AOC and LZM activities in the serum clearly decreased, indicating that the antioxidant system and nonspecific immune mechanism of subadult Chinese sturgeon appeared to be inhibited, which could raise the sensitivity of the Chinese sturgeon to various pathogens. The results of this study indicate that subadult Chinese sturgeon could achieve normal growth in the RAS, but that growth and hematology were significantly affected when the TAN concentration in the water was higher than 2 mg/L for an extended period.     

Survival and growth of early life stages of leaf fish (Monocirrhus polyacanthus,Heckel 1840) cultured under different stocking densities and live food densities

The objective of this study was to evaluate the effects of different live foods, (Artemia sp. and Moina minuta), and different stocking densities on the larval rearing success of the leaf fish, Monocirrhus polyacanthus. A completely randomized factorial design (3 × 3; three replicates) was used. Two subsequent experiments were performed for each live food, using three food densities (100, 200 and 300 prey per larva) and three stocking densities (10, 15 and 20 larvae L^?1). Fish were fed twice a day. Water quality parameters pH (4.08–4.02), dissolved oxygen (3.7–3.6 mg L^?1), temperature (27.9–27.8°C), conductivity (147.2–127.4 μs cm^?1) and total ammonia (0.78–0.38 μg L^?1) were determined. Weight gain, specific growth rate (SGR), body mass, relative condition factor and survival were evaluated. The water quality was influenced by the live food and stocking densities. Fish fed M. minuta showed better weight gain, specific growth ratio (SGR), biomass gain, relative condition factor and survival than in the other treatment. Artemia sp. showed no improved influence on the larvae performance subjected to different treatments. The beneficial role in growth and survival of leaf fish larva when fed with M. minuta is discussed.     

Ionregulation in juvenile swordspine snook (Centropomus ensiferus,Poey, 1860) in relation to environmental salinity

Ninety‐nine swordspine snook Centropomus ensiferus (9.80 ± 0.3 g, mean ± SE) were studied in order to evaluate the influence of salinity on physiological properties under rearing conditions. Growth performance, survival rates, and ion concentrations (Na⁺, K⁺, Cl^?) as well proximal composition were measured over 76 days. Fish were exposed to three experimental salinities (0, 10, 20 ‰ , three replicates per treatment) and maintained in plastic tanks with a recirculation system equipped with flow‐through aquaria pumps (533 L per tank). Fish were fed twice daily to apparent satiation; at the end of the experiment the weight of fish kept in 10 ‰ was higher than that of fish kept in 0 and 20 ‰ , however no significant differences (P > 0.05) were observed among the experimental salinities. Survival was significantly lower in 10 ‰ salinity than in fish kept in 20 and 0 ‰ salinities. No significant differences (P > 0.05) were found in the Condition factor (K), specific growth rate (SGR), or in plasma Na⁺, K⁺, or Cl^? concentrations among treatments. Salinities also did not affect body composition (P > 0.05), but were significantly lower (P < 0.05) than at the start of the experiment. However, towards the end of the experiment a large accumulation of visceral fat in fish farmed in the three salinities (VFI > 4%) was observed. Water quality was within the optimum range (T: 28.7 ± 0.1°C; O2: 5.6 ± 0.1 mg L^?1; ammonia: 0.2 mg L^?1) for the growth of swordspine snook. Data indicates that C. ensiferus is an ionoregulator fish and able to cultivate successfully in various osmotic conditions, and in turn, maintain high levels of survival in captivity.     

Influence of Tribulus terrestris extract on the survival and histopathology of Oreochromis mossambicus (Peters, 1852) fry before and after Streptococcus iniae infection

The aim of this study was to determine the effects of Tribulus terrestris extract (TT) on growth performance, disease resistance and histopathological changes in intestine and liver tissues of Oreochromis mossambicus (Peters, 1852) first‐feeding fry before and after exposure to Streptococcus iniae. Five isonitrogenous and isocaloric diets were formulated to contain 0 (control), 200, 400, 600, and 800 mg kg^?1 TT. After feeding for 45 days, fish were infected with S. iniae and mortalities recorded. Final weight, weight gain and SGR of tilapia fry fed the 400 mg kg^?1 TT diet were significantly greater than that of control diet. In the challenge experiment, the best survival rate was obtained with 400 mg kg^?1 TT supplementation. Infection by S. iniae appeared to have a negative effect on histopathological findings and outcome than did TT‐800 used alone. However, administration of TT (200 or 400 mg extract kg^?1) resulted in overall improvement in the intestine and liver histopathology, emphasizing the protective potential of TT. The present study suggests the protective potential of TT in alleviating intestinal and hepatic damage that can occur after a S. iniae infection. It was concluded that 400 mg kg^?1 TT can enhance growth and disease resistance during first–feeding of O. mossambicus fry. This suggests that TT may be an alternative to antibiotics in controlling streptococcal disease in tilapia culture.     

Pharmacokinetics of oxytetracycline in yellow catfish [Pelteobagrus fulvidraco (Richardson, 1846)] with a single and multiple‐dose oral administration

A pharmacokinetic study of oxytetracycline (OTC) following a single (100 mg kg^?1) or a multi‐dose (100 mg kg^?1 for 5 days) oral administration was carried out in yellow catfish, Pelteobagrus fulvidraco. After oral administration at 25°C, a one‐compartment model was developed. The absorption half‐life (t_1/2(ka)) was 3.92, 1.44, 2.75, and 3.34 h in plasma, muscle, liver, and kidney after the single dose, and 0.35, 0.22, 0.42, 0.32 h after the multi‐dose, respectively. The order of peak concentration (C_max) was liver > kidney > plasma > muscle, at 3.48 μg g^?1, 2.90 μg g^?1, 1.46 μg ml^?1, and 1.39 μg g^?1 after the single dose, and 14.02 μg g^?1, 8.51 μg g^?1, 4.17 μg ml^?1, and 3.84 μg g^?1 after the multi‐dose, respectively. The elimination half‐lives (t_1/2(ke)) of OTC in plasma, muscle, liver, and kidney were calculated to be 7.64, 26.29, 19.08, and 10.61 h after the single dose, and 47.54, 70.99, 49.87, and 47.73 h after the multi‐dose, respectively. The results suggest that OTC was absorbed faster after the multi‐dose than after the single dose, suggesting that OTC could be more efficacious after the multi‐dose and more effective in the control bacterial diseases in aquaculture, with the side effects of longer withdrawal periods.     

Effects of supplementing the diets of Mugil liza Valenciennes, 1836 juveniles with citrus pectin

The aim of this study was to evaluate whether increasing the levels of citrus pectin has anti‐nutritional effects when included in the diets of Mugil liza juveniles, including its effects on hepatic metabolism and modulation of the microbial community. Fish (mean weight 0.38 g ± 0.01) were stocked at a density of 15 fishes per tank and fed for 60 days with either a control diet or one of three diets containing different levels of pectin (4, 8 and 12%), in triplicates. The temperature, dissolved oxygen, pH, salinity and alkalinity during the trial were, respectively, 25.0°C ± 0.1, 6.82 ± 0.02 mg L^?1, 8.10 ± 0.06 and 147 mg ± 12.93 CaCO₃. The total ammonia‐nitrogen (TAN) in PC4, PC8 and PC12 treatments were, respectively, 0.69 ± 0.38; 0.57 ± 0.35; 0.64 ± 0.39 and 0.45 ± 0.23 mg L^?1. The increasing diet viscosity with pectin inclusion did not cause significant differences in growth. Fish fed with pectin demonstrated a reduction in their percentage body dry matter, crude protein and ash. Hepatic glycogen levels were elevated in the group fed with 12% pectin, while there were no effects in cholesterol and triglycerides levels. Citrus pectin did not exert any modulatory effect on the microbial community. Although the pectin‐supplemented fish showed enteritis during the experimental period, this did not impair animal performance. However, the use of this polysaccharide as a binder in mullet (Mugil liza) diets for longer periods should be considered with caution.     

Evaluation of optimum dietary vitamin E requirements using DL‐α‐tocopheryl acetate in the juvenile eel,Anguilla japonica

The study aimed at evaluating the optimum dietary vitamin E requirements using DL‐α‐tocopheryl acetate in the juvenile eel, Anguilla japonica, as assessed by fish growth performance and fish body composition. Five semi‐purified experimental diets were formulated to contain 0 (TA₁), 15 (TA₁₇), 30 (TA₃₂), 60 (TA₆₂) and 120 (TA₁₁₉ mg TA kg^?1 diet on a dry matter (DM) basis in the form of DL‐α‐tocopheryl acetate (TA). After a 4‐week conditioning period, fish (15 ± 0.3 g) were randomly distributed into aquaria in groups of 20 at 25 ± 1.0°C (mean ± SD). One of the five diets was fed on a DM basis to fish in three randomly selected aquaria twice daily to satiation (approximately 3% of wet body weight per day at the beginning and 2% of wet body weight per day at the end of the feeding trial) for 12 weeks. At the end of the 12‐week feeding trial, weight gain (WG), specific growth rate (SGR), feed efficiency (FE) and protein efficiency ratio (PER) were determined; these were significantly lower in control fish than in fish fed supplemented diets (P < 0.05). The values for fish fed TA₁₇ were significantly higher than for fish fed TA₁, TA₆₂ or TA₁₁₉ (P < 0.05). There were no significant differences in WG, FE or PER among fish that were fed TA₁₇ and TA₃₂, among those that were fed TA₃₂ and TA₆₂, and among those that were fed TA₆₂ and TA₁₁₉ (P > 0.05). There were also no significant differences in SGR among fish fed TA₃₂, TA₆₂ or TA₁₁₉ (P > 0.05). A broken‐line regression analysis on the basis of WG, SGR, FE and PER showed that dietary vitamin E requirements of juvenile eels were 21.2, 21.6, 21.2 and 21.5 (mg kg^?1 diet), respectively. These results indicate that the dietary vitamin E requirement could be <21.2 mg kg^?1 but <21.6 mg kg^?1 diet in juvenile eel, A. japonica, when DL‐α‐tocopheryl acetate is used as the dietary vitamin E source.     

Increases in benthic community production and metabolism in response to marine‐derived nutrients from spawning Atlantic salmon (Salmo salar)

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Feeding response of the cotton aphid,Aphis gossypii,to sublethal rates of flonicamid and imidacloprid

The cotton aphid, Aphis gossypii Glover (Hemiptera: Aphididae), is an important sap‐sucking pest of many plants, including melons and peppers. This study was conducted to determine the effects of sublethal exposure to flonicamid and imidacloprid and the mechanisms by which these insecticides affect the feeding behavior of A. gossypii. The median lethal concentrations (LC₅₀) of flonicamid and imidacloprid for adult A. gossypii were 2.40 and 1.92 mg l^?1, respectively. The lower lethal concentrations of flonicamid were 1.01 mg l^?1 (LC₃₀) and 0.29 mg l^?1 (LC₁₀), and those of imidacloprid were 0.82 mg l^?1 (LC₃₀) and 0.24 mg l^?1 (LC₁₀). The developmental period of A. gossypii nymphs at LC₃₀ was 3.6 days for both insecticides, which was shorter than that of the untreated controls (4.2 days). Longevity and total fecundity of A. gossypii adults were decreased at the sublethal concentrations of both insecticides. The lowest net reproductive rate was observed in A. gossypii treated with the LC₃₀ of flonicamid. Feeding behavior analyses using an electrical penetration graph showed that sublethal concentrations of flonicamid and imidacloprid had significant effects on the duration of phloem ingestion. Higher doses of flonicamid induced starvation by inhibiting phloem ingestion, whereas imidacloprid acted as a contact toxin rather than an inhibitor of feeding behavior.     

Effects of varying levels of dietary vitamin E (α‐tocopherol) on growth performance,proximate and fatty acid composition of juvenile silver pomfret (Pampus argenteus Euphrasen, 1788)

This study investigated the effects of elevated dietary levels of vitamin E (α‐tocopherol) on growth performance, proximate composition and fatty acid profiles of juvenile silver pomfret, Pampus argenteus. Three semi‐purified experimental diets were formulated to contain 49% protein and 16% lipid. High docosahexaenoic acid (DHA) tuna oil was added to the diets to supplement DHA. A graded level of vitamin E (0‐, 50‐, and 100 mg kg^?1) was added to experimental diets 1 to 3, respectively. Analyzed vit. E levels were 155.2, 195.3 and 236.4 mg kg^?1 in diets 1, 2 and 3, respectively. The experiment was conducted for 12 weeks with juvenile silver pomfret (29.6 ± 7.6 g) using a flow‐through system consisting of nine 1‐m³ tanks. Each treatment had three replicates and fish were stocked at the rate of 20 m^?3. Growth performance and feed utilization parameters of fish fed diets 2 and 3 were significantly (P < 0.05) higher than in fish fed diet 1, but the parameters in diets 2 and 3 did not differ significantly (P > 0.05). Although whole body protein levels were not influenced by the dietary vit. E levels, whole body lipid in fish fed diet 2 was significantly higher than in fish fed the other diets. The whole body vit. E levels in fish fed diet 2 (22.6 mg kg^?1) and diet 3 (24.1 mg kg^?1) were significantly (P < 0.05) higher than in those fed diet 1 (18.2 mg kg^?1). Whole body total saturated fatty acids were significantly lower, and DHA levels higher in fish fed diets 2 and 3 than those fed diet 1. The results of the present study suggest that increasing dietary supplementation of vit. E in high lipid diets enhances the growth performance of fish and that a dietary level of 196 mg kg^?1 vit. E is suitable for the growth of silver pomfret.     

Strong impact of nitrogen loading on submerged macrophytes and algae: a long‐term mesocosm experiment in a shallow Chinese lake

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Effects of Ca and Mg concentrations in seawater on the growth and energy budget of juvenile Paralichthys olivaceus (Temminck & Schlegel, 1846)

Effects of seawater calcium (Ca) and magnesium (Mg) concentrations on the growth and energy budget of juvenile Paralichthys olivaceus (Temminck & Schlegel, 1846) were investigated at 20°C and a salinity of 30 psu. The Ca/Mg ratio (Ca : Mg = 1 : 3) in the experimental water was kept constant. Five treatments were set: C1, C2, C3, C4, and C5, and the Ca and Mg concentrations were 700, 1100, 1600, 2200, and 2800 (mg L^?1), respectively. After a 60‐day feeding trial the P. olivaceus survival rates were not affected significantly by Ca or Mg concentrations in the range of 700–2800 mg L^?1. However, the specific growth rates (SGR) and weight gain (WG) of all treatments decreased with ascending Ca and Mg concentrations. The Ca and Mg concentrations had a strong influence on various energy parameters, namely, energy deposited for growth (G), energy lost for respiration (R), and energy lost in excretion (U), but had little influence on energy lost in feces (F). This indicated that the growth rate differences under different concentrations of Ca and Mg mainly resulted from differences of assimilation efficiency and energy channeled into respiration. The highest net growth efficiency was attained at the lowest concentration of Ca and Mg in seawater, and the higher concentrations of Ca and Mg increased the energy channeled to respiration and excretion, which led to significant reduction in growth. Therefore, the optimal growth of P. olivaceus could be obtained by regulating the concentration of Ca and Mg at 700 mg L^?1, where the average energy budget was: 100C (100% energy consumed in food) = 47.21 (±0.63) G + 32.89 (±0.42) R + 16.71 (±0.56) F + 3.19 (±0.05) U.     

Reference values for selected hematological and serum biochemical parameters of Senegalese sole (Solea senegalensis Kaup, 1858) juveniles under intensive aquaculture conditions

This work aims to establish normal reference intervals for selected hemato‐biochemical parameters, based on their potential clinical relevance, and which may contribute to evaluating the health, nutritional and welfare status of Senegalese sole (Solea senegalensis Kaup, 1858) juveniles. Thirty‐one healthy Senegalese sole juveniles grown under intensive aquaculture conditions were used in the study. Based on the robust method with Box–Cox transformation data the established reference intervals for hematological parameters were: hematocrit 12–26%, hemoglobin 2.8–6 g dl^?1, erythrocytes 90–97.0% total, leucocytes 4–10% total; erythrocyte indices and differential leucocytes counts were also evaluated. Reference intervals for biochemical parameters were (g dl^?1) glucose 19–86 mg dl^?1, total protein 2.6–6.3, albumin 1–2.34, globulins 1.8–4.1, lipids 0.7–1.3, triglycerides 0.3–1.8, total cholesterol 0.1–0.9 g dl^?1, HDL‐cholesterol 4–65 mg dl^?1, LDL‐cholesterol 7–532 mg dl^?1, sodium 124–202 mmol L^?1), potassium 1.1–4.6 mmol L^?1, calcium 7.6–13.2 mg L^?1, magnesium 1.8–4.8 mg L^?1, inorganic phosphorus 3.4–9.5 mg L^?1, alkaline phosphatase 93–598 U L^?1, aspartate aminotransferase 118–605 U L^?1, lactate dehydrogenase 8.7–782 U L^?1, and creatine phosphokinase 31.5–552 U L^?1. This data is expected to provide a valuable tool to monitor the stress, health and nutritional conditions of Senegalese sole juveniles under aquaculture production.     

Effects of metalaxyl enantiomers stress on root activity and leaf antioxidant enzyme activities in tobacco seedlings

The objective of this experiment was to study the effects of metalaxyl enantiomers on the activity of roots and antioxidative enzymes in tobacco seedlings. Water culture experiment was conducted to analyze the effects of different concentrations of metalaxyl enantiomers (30 and 10 mg L^?1) on root activity and leaf superoxide dismutase (SOD), peroxidase (POD), and catalase (CAT) activities and malondialdehyde (MDA) content of tobacco seedlings. The results showed that metalaxyl significantly inhibited root activity and significantly improved leaf SOD, POD, and CAT activities and MDA content. A better physiological response in tobacco seedlings was observed at 30 mg L^?1 than at 10 mg L^?1 metalaxyl. The stereoselectivity for different enantiomers had no obvious effect on root activity and the leaf POD activity, but it affected significantly the SOD and CAT activities and MDA content. The SOD activity was promoted more by R‐enantiomer than by S‐enantiomer at 30 mg L^?1 metalaxyl, and the same effect was observed on CAT activity from the beginning to the end of the stress period. The MDA content under the stress by R‐enantiomer was higher than that under the stress by S‐enantiomer at 10 mg L^?1 metalaxyl.     

Effects of norfloxacin on the drug metabolism enzymes of two sturgeon species (Acipenser schrencki and Acipenser ruthenus)

The enzyme activities of 7‐ethoxycoumarin O‐deethylase (ECOD) and glutathione S‐transferase (GST), and on glutathione (GSH) content, involved in metabolism of the antibiotic Norfloxacin (NFLX), were investigated in Acipenser schrencki and Acipenser ruthenus. Sturgeons weighing 45–55 g were kept in an aquarium (0.5 m × 0.5 m × 0.9 m) for two weeks under controlled conditions (fish density 88 individuals per m³, 18°C) before the experiment. The two species of sturgeon were divided into five groups each (n = 15 in each group), with each group subdivided into three replicates of five fish per tank. A control group in which distilled water was administered orally was also tested. NFLX was forced into the stomachs of the fish at a concentration of 20, 40, 60, 80 and 100 mg kg^?1 body weight, respectively. ECOD activities in liver microsomes, and GST activity and GSH content in liver microsomes and blood plasma, were measured and compared. Results indicate that ECOD activity is progressively inhibited with increasing NFLX concentrations. ECOD activity varied from 0.12 nmol mg^?1 min^?1 to 0.07 nmol mg^?1 min^?1, demonstrating an inhibition rate of 60.83% in A. schrencki and 65.14% in A. ruthenus. In both species tested, GST and GSH levels exhibited a trend of first increasing, and then decreasing with increasing NFLX levels, reaching a peak value at 40 mg per kg^?1 body weight. Thus, the presented results indicate that NFLX can induce a change in the activity of some drug metabolism related enzymes such as ECOD and GST in vivo.     

Contrasting effects of low‐level phosphorus and nitrogen enrichment on growth of the mat‐forming alga Didymosphenia geminata in an oligotrophic river

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Hematology and plasma chemistry of wild shortnose sturgeon Acipenser brevirostrum from Delaware River,USA

The effects of gender, maturity, intersex condition and annual and seasonal variability were studied on hematology and plasma chemistry of wild shortnose sturgeon Acipenser brevirostrum from the Delaware River. A total of 68 fish were captured by gill net and examined in May‐June, and 61 additional fish were captured and examined in November during 2006–2011. Total leukocyte counts (WBC), leukogram, PCV and the plasmatic concentrations of 13 biochemical analytes were measured from these fish using standard clinical methods. Season and gender had no effect on hematologic indices, but PCV was inversely related to maturity of fish (robust intervals: 27–40% in immature fish, 21–36% in mature fish). Significant annual variation was detected in eosinophil (annual range in robust interval: 0–1176 lower limit, 670–7882 upper limit) and monocyte (0–210 lower limit, 560–1980 upper limit) counts (cells μl^?1). The lower limit of the robust interval varied annually by as much as 6% for sodium and 12% for chloride, while the upper limit of the robust interval varied annually by as much as 8% for sodium and 15% for chloride. Seasonal differences in mean sodium and chloride (6–7% higher in autumn) and proteins (5–13% higher in autumn) may reflect environmentally induced changes in osmoregulation, while aspartate aminotransferase was 38–55% higher in the spring. In females, calcium and total protein were highest in mature fish (robust intervals: 10.5–22.1 mg dl^?1 Ca²⁺, 4.1–6.9 g dl^?1 TP) compared to immature (7.3–16.9 mg dl^?1 Ca²⁺, 2.8–5.2 g dl^?1 TP) and developing fish (7.8–18.9 mg dl^?1 Ca²⁺, 3.2–5.6 g dl^?1 TP), indicating changes associated with vitellogenesis. Glucose was significantly higher in females (robust interval: 23–167 mg dl^?1) than males (35–138 mg dl^?1), possibly indicating gender‐based differences in energetic requirements. Intersex condition was associated with lowered glucose, potassium and creatinine phosphokinase. Reference intervals reported here are useful for evaluating the health and physiological condition of shortnose sturgeon.     

Environmental remediation potential of Perinereis aibuhitensis (Polychaeta) based on the effects of temperature and feed types on its carbon and nitrogen budgets

The effects of three temperatures (15°C, 20°C and 25°C) and four feed types (artificial feed, AF; sediment, SM; fish faeces, FF; and fish meat, FM) on the growth, carbon budget and nitrogen budget of the polychaete Perinereis aibuhitensis were evaluated over a 35 day period. The final body weight and specific growth rate (SGR) of P. aibuhitensis were significantly affected by temperature and feed types (T, F?=?15.831, P?=?0.000; Feed, F?=?81.827, P?=?0.000), but the interaction between these factors was not significant (F?=?0.435, P?=?0.848). The worms achieved the highest SGR in the AF group at 20°C. However, the SGR in the SM group was only half that of the other groups. The food conversion efficiency (FCE) was significantly lower at 25°C than at 15°C and 20°C (P?P?=?0.000), with a mean of 39.83%. The apparent digestibility rate (ADR) at 25°C was significantly higher than at 15°C and 20°C (P?相似文献