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1.
The oxygen consumption (02) and ammonia excretion (N) of juvenile and adult common wolffish was measured in culture tanks in the laboratory. The oxygen consumption and ammonia excretion were affected by temperature (C), fish size and feeding rate. For juveniles (0.5 kg; 7C) the diel oxygen consumption rate varied between 37 and 62 mg O2 kg-1 h-1 and ammonia excretion between 2.3 and 5.7 mg N kg-1 h-1. The corresponding rates for adult fish (6.9 kg; 7C) were 29-44 mg O2 kg-1 h-1 and 1.2–3.1 mg N kg-1 h-1. The weight-specific oxygen consumption (mg O2 kg-1 h-1) was described by the following formulae: O2 (7C) = 0.17* W0.83 and O2 (12C) = 0.39 * W0.73 and the corresponding ammonia excretion (mg N kg-1 h-1) by: N(7C) = 0.024 W0.75 and N(12C) = 0.073 W0.60, where W is fish weight in g.  相似文献   

2.
Oxygen consumption (OC) and ammonia excretion rates (AE) of perch were measured under commercial‐like conditions (temperature 23.3 °C) in both fed (F) and feed‐deprived groups (D). Measurements were taken in triplicate in six sized batches of perch ranging from 44.8 to 336.2 g. The mean daily OC was 288.3–180.6 mg O2 kg?1 h?1 for group F fish ranging in size from 44.8 to 279.4 g body weight. The mean daily AE expressed as total ammonia nitrogen (TAN) was 13.8–5.2 mg TAN kg?1 h?1 in the same groups. Daily peaks of OC in group F perch were observed 6 h after the onset of feeding for each size group with relatively stable values up to the end of feeding. Peaks of daily AE in group F perch were observed 10 h after the onset of feeding in each size group, with a rapid decrease up to 16 h after onset. In group D, OC was 181.1–110.5 mg O2 kg?1 h?1 in the weight range 57.9–336.2 g. The daily mean AE was 1.7–0.5 TAN kg?1 h?1 in this group. No dramatic peaks of OC and AE were observed in group D perch.  相似文献   

3.
The effects of transporting silver catfish (Rhamdia quelen) for 6 h in plastic bags containing 0 (control), 30 or 40 µL/L of essential oil (EO) from Lippia alba leaves were investigated. Prior to transport, the fish in the two experimental groups were sedated with 200 µL/L of EO for 3 min. After transport, dissolved oxygen, carbon dioxide, alkalinity, water hardness, pH, temperature and un-ionized ammonia levels in the transport water did not differ significantly among the groups. However, total ammonia nitrogen levels and net Na+, Cl? and K+ effluxes were significantly lower in the groups transported with EO of L. alba than those in the control group. PvO2, PvCO2 and HCO3 ? were higher after transporting fish in 40 µL/L of EO of L. alba, but there were no significant differences between groups regarding blood pH or hematocrit. Cortisol levels were significantly higher in fish transported in 30 µL/L of EO of L. alba compared to those of the control group. The metabolic parameters (glycogen, lactate, total amino acid, total ammonia and total protein) showed different responses after adding EO to the transport water. In conclusion, while the EO of L. alba is recommended for fish transport in the conditions tested in the present study because it was effective in reducing waterborne total ammonia levels and net ion loss, the higher hepatic oxidative stress in this species with the same EO concentrations reported by a previous study led us to conclude that the 10–20 µL/L concentration range of EO and lack of pre-sedation before transport are more effective.  相似文献   

4.
This study investigated the efficacy of the essential oil (EO) of Aloysia triphylla as an anesthetic for albino and gray strains of silver catfish, Rhamdia quelen. Juveniles were exposed to concentrations between 20 and 800 μL L?1 EO of A. triphylla to evaluate time of induction and recovery from anesthesia. In another experiment, both strains were divided into four groups such as 0 (control), 30, 40, or 50 μL L?1 EO and transported for 5 h. The longest time for anesthetic induction and recovery was observed in the albinos. Both strains reached anesthesia in the 100–800 μL L?1 (11.1–1.24 min) range, without mortality, being 200 μL L?1 the best response considering time to anesthesia (5.35 min). Albinos transported with all EO concentrations showed higher values of carbon dioxide in the water of transport, but lower levels were observed in grays transported with 40 and 50 μL L?1 EO when compared to control fish. The same concentrations did not prevent significant whole-body cortisol rise at the end of transport in the albino strain. Juveniles of both strains transported with EO presented lower ion loss to the water compared to control fish. The EO of A. triphylla is an effective anesthetic for albino and gray silver catfish. This EO increases whole-body cortisol levels in the albino strain, but as it reduces net ion loss as in the gray strain, it can be also recommended for transport.  相似文献   

5.
Oxytetracycline (OTC) is employed in fish farms to contest or prevent bacterial infections. We simulated an OTC treatment at therapeutic level (75 mg kg?1) and at higher doses (150, 300 mg kg?1) for 10 days. A withdrawal period of 10 days was considered for treated carp, carrying out the same chemical and biochemical analyses (total glutathione, superoxide dismutase, catalase, glutathione peroxidase, glutathione reductase, glutathione S-transferase and malondialdehyde). The aim was to obtain data related to the carryover in muscle and on variations in the antioxidant indicators in liver and kidney. The OTC residual levels in muscle showed a dose–response relationship. After 10 days of treatment at the recommended dose (75 mg kg?1), the mean value in muscle was 295 μg kg?1. After 10 withdrawal days, residues in all treated groups were not entirely eliminated by fish. Residues of recommended 75 mg kg?1 OTC dose were lower than the maximum permitted by EEC regulation: 100 μg kg?1. Disturbance in the antioxidant systems in liver and kidney was recorded in (150, 300 mg kg?1) carp, as well as during the withdrawal period. A lowered superoxide dismutase activity and higher levels of catalase, glutathione peroxidase, glutathione reductase and glutathione were evaluated in liver, while in kidney only higher malondialdehyde and glutathione S-transferase concentrations were recorded for 300 mg kg?1 dose. The therapeutic OTC dose exerted lower effects, and only in liver, enhancement of GPx and GR activities was recorded. After the withdrawal period, altered antioxidant responses in tissues were restored for all three OTC doses.  相似文献   

6.
The effect of irradiance and temperature on the photosynthesis of two Japanese agarophytes, Gelidium elegans and Pterocladiella tenuis (Gelidiales), was determined using dissolved oxygen sensors and pulse amplitude modulated (PAM) fluorometry. Gross photosynthesis and dark respiration rates were determined over a range of temperatures (8–36 °C). The highest gross photosynthetic rates were 40.3 and 37.0 mg O2 g ww ?1  min?1 and occurred at 24.3 and 25.5 °C [95 % Bayesian credible interval (BCI) 20.7–28.0 and 23.4–28.3 °C], respectively. The dark respiration rate in G. elegans and P. tenuis increased with increasing temperature at a rate of 0.10 and 0.31 mg O2 g ww ?1  min?1 °C?1 , respectively. Modeling the net photosynthesis–irradiance (P–E) responses of G. elegans and P. tenuis at 20 °C revealed that the net photosynthetic rates quickly increased at irradiance levels below the estimated saturation irradiance of 88 and 83 µmol photons m?2 s?1, with a compensation irradiance of 14 and 19 µmol photons m?2 s?1, respectively. The highest value of the maximum effective quantum yield (Φ PSII) occurred at 20.1 °C (BCI 18.9–21.5 °C) and 21.3 °C (BCI 20.2–22.5 °C) for G. elegans and P. tenuis and was 0.49 and 0.45, respectively. These optimal temperatures of Φ PSII were relatively lower than those determined by the photosynthesis–temperature model of oxygen evolution. The temperature response of these species indicates that they are probably well adapted to the current range of seawater temperatures in the study site but that they are near the boundary of their tolerable limits.  相似文献   

7.
A 45-day feeding trial was conducted to evaluate the effects of dietary citric acid on growth, digestive enzyme and disease resistance of white shrimp, Litopenaeus vannamei. Shrimp with initial body weight of 5.57 ± 0.21 g were fed with basal diet supplemented with 0.0 g kg?1 (control), 1.0, 2.0, 3.0, 4.0 and 5.0 g kg?1 citric acid. Results showed that weight gain was increased by 15.9 % and feed conversion ratio was decreased by 0.17 by 2.0 g kg?1 dietary citric acid compared with control group (P < 0.05). Intestinal protease activity of shrimp fed 2.0 g kg?1 citric acid was significantly higher (P < 0.05) than that of control group. No significant difference was found in intestinal amylase activity among treatments (P > 0.05). The activities of serum phenoloxidase, superoxide dismutase and lysozyme in 2.0 and 3.0 g kg?1 citric acid group were significantly higher, and accumulative mortalities of the two groups on the fourth day after injection of Vibrio alginolyticus were significantly lower than those of control group (P < 0.05). Results above demonstrated that dietary citric acid could improve growth performance, immunity and resistance against V. alginolyticus. The supplementation level of citric acid in diet was suggested to be 2.0–3.0 g kg?1 for white shrimp.  相似文献   

8.
This study evaluated the effect of graded levels of dietary ascorbic acid (AA) (12.47, 20.27, 115.44, 475.50, 737.72, and 850.70 mg kg?1) on growth, hematology, intestinal morphometry, and phagocyte activity of hybrid sorubim Pseudoplatystoma reticulatum × Pseudoplatystoma corruscans. Fish (n = 420, 14.57 ± 2.71 g, 15.11 ± 0.90 cm) were distributed in 30 polyethylene tanks (80 l) (5 replicates per treatment with 14 fish per tank) and fed for 45 days. Dietary treatment did not have a significant effect on growth metrics (P > 0.05). Fish fed 737.72 mg AA kg?1 had a higher villi height (289.80 ± 19.96 μm) (P < 0.05) than fish fed 850.70 mg AA kg?1 (245.4 ± 18.25 μm). Hemoglobin in fish fed 850.70 mg AA kg?1 (5.34 ± 0.96 g dl?1) was higher (P < 0.05) than fish fed 12.47 mg AA kg?1 (3.42 ± 0.55 g dl?1) and 20.27 mg AA kg?1 (3.06 ± 1.26 g dl?1). The erythrocyte number of hybrid sorubim fed 115.40 mg AA kg?1 (1.73 ± 0.27 × 106 μl?1) and 475.50 mg AA kg?1 (1.70 ± 0.28 × 106 μl?1) were higher (P < 0.05) than in those fed diets containing 20.27 mg AA kg?1 (1.11 ± 0.34 × 106 μl?1). There was no significant effect (P > 0.05) of dietary AA on leukocyte and thrombocyte and on phagocyte activity and phagocyte index. Inclusion of AA in feed seems to increase the integrity of the intestinal mucosa and stimulate erythropoiesis in hybrid sorubim catfish.  相似文献   

9.
This study examined the effects of dietary esterified astaxanthin concentration on coloration, accumulation of carotenoids, and the composition of carotenoids over time in the skin of Amphiprion ocellaris. Juveniles of 30 days-post-hatch were fed 40, 60, 80, or 160 mg esterified astaxanthin per kg diet (mg kg?1) for 90 days. Skin coloration was analyzed using the hue, saturation, and luminosity model. Increased astaxanthin concentrations and duration on diet lead to improvements in skin color, that is, lower hues (~27–29 to ~14–17; redder fish), higher saturation (~77 to ~87 %), and lower luminosity (~43 to ~35 %). Fish fed 80 and 160 mg kg?1 astaxanthin feed showed significant coloration improvements over fish fed lower astaxanthin feeds. Increasing both dietary astaxanthin concentration and time on the feed resulted in significant increases in total skin carotenoid concentration (0.033–0.099 μg mm?2). Furthermore, there was a significant linear relationship between hue and total skin carotenoid concentration. Compositionally, free astaxanthin and 4-hydroxyzeaxanthin were the major skin carotenoids. 4-hydroxyzeaxanthin was previously unreported for A. ocellaris. Carotenoid composition was affected by duration on diet. Fraction 4-hydroxyzeaxanthin increased by ~15 %, while free astaxanthin decreased equivalently. The transition from 4-hydroxyzeaxanthin to free astaxanthin appears to follow a reductive pathway. Results suggest that managing coloration in the production of A. ocellaris juveniles requires manipulation of both dietary astaxanthin concentration and period of exposure to astaxanthin containing diet. In order to achieve more orange–red-colored fish, feeding 80–160 mg kg?1 esterified astaxanthin for an extended duration is recommended.  相似文献   

10.
This study was conducted to evaluate dietary protein and carbohydrate requirement of juvenile Hawaiian limpets Cellana sandwincensis. A total of 64 juvenile limpets (3.12 ± 0.86 g) were fed five different dietary protein levels ranging from 270 to 470 g kg?1 for 90 days. Carbohydrate and lipid levels were held constant at 180 and 49.7 g kg?1, respectively. Weight gain and growth rates of the animals did not differ significantly (P > 0.05) among the protein levels ranging from 270 g kg?1 (0.30 % day?1) to 470 g kg?1 (0.23 % day?1). Next, opihi were fed four diets with protein levels from 210 to 500 g kg?1 with a constant carbohydrate level at 120 g kg?1. Weight gain and specific growth rates of opihi increased with increasing dietary protein from 210 to 350 g kg?1, and significantly (P < 0.05) decreased at the 500 g kg?1 diet. Highest weight gain, growth rates, and protein efficiency ratio were achieved at 350 g kg?1. Elevated carbohydrate levels (180–370 g kg?1) produced a significant difference (P < 0.05) in growth. The fastest growth rates of animals were obtained with 270 g kg?1 (0.27 % day?1) and 320 g kg?1 (0.26 % day?1). The weight gain of animals fed 180 and 370 g kg?1 carbohydrate diets were significantly (P < 0.05) lower than those of animals fed 270 and 320 g kg?1. We conclude that about 350 g kg?1 protein and 320 g kg?1 carbohydrate levels could be used for opihi.  相似文献   

11.
Lipid peroxidation, protein oxidation and antioxidant activities of muscle, intestine, hepatopancreas and serum in juvenile Jian carp (Cyprinus carpio var. Jian) were investigated after feeding graded levels of biotin (0.010, 0.028, 0.054, 0.151, 0.330, 1.540 and 2.680 mg kg?1 diet) for 63 days. Both malondialdehyde and protein carbonyl content in all studied tissues and serum were the lowest in fish fed diets containing 0.151–0.330 mg biotin kg?1 diet and then increased in fish fed the diet with 2.680 mg biotin kg?1 diet (P < 0.05). Similarly, glutamate–oxaloacetate transaminase and glutamate–pyruvate transaminase activities in serum significantly decreased with biotin levels up to 0.151 mg kg?1 diet (P < 0.05). Conversely, capacities of anti-hydroxyl radical (AHR) and anti-superoxide anion (ASA) in the detected tissues and serum significantly improved with biotin levels up to 0.054–1.540 mg kg?1 diet and then decreased in 2.680 mg biotin kg?1 diet group for muscle and intestinal AHR as well as hepatopancreas ASA (P < 0.05). Activities of superoxide dismutase in all studied tissues and serum significantly elevated with biotin levels up to 0.330 mg kg?1 diet and then decreased when fish fed the diet with 2.680 mg biotin kg?1 diet, except intestine (P < 0.05). Meanwhile, activities of catalase, glutathione peroxidase, glutathione-S-transferase and glutathione reductase and total thiol content in all studied tissues and serum showed the upward trend with biotin supplementations (P < 0.05). These results indicated that biotin improved antioxidant status and depressed lipid peroxidation and protein oxidation in all studied tissues and serum.  相似文献   

12.
Triplicate groups of one hundred Tra catfish (8 g?±?0.2) were fed seven test diets containing increasing levels of AFB1 (0, 50, 100, 250, 500, and 1000 μg AFB1 kg?1). Additionally Mycofix® Secure was added at 1.5% to one diet containing 500 μg AFB1 kg?1. Results showed that Tra catfish are sensitive to AFB1. Reduction in weight gain (P?<?0.05) was observed for fish fed 50 μg AFB1 kg?1 and declined further with increasing levels of AFB1 in the diets. Fish fed diets contaminated with 500 and 1000 μg AFB1 kg?1 showed increased (P?>?0.05) hepatosomatic index (HIS), while an increase in adipose somatic index (ASI) was observed in fish fed 50 μg AFB1 kg?1 and above when compared to the control and Mycofix® diets. After 12 weeks, blood serum analysis revealed higher alanine aminotransferase (ALT) and aspartate aminotransferase (AST) levels in fish fed the 50, 100, and 250 μg AFB1 kg?1 suggesting occurrence of liver damage. Disease resistance of fish exposed to Edwardsiella ictaluri was also compromised by the presence of AFB1 in the feed and was directly related to the contamination level. Seven days after Edwardsiella ictaluri exposure, survival rates were 50, 41.7, 31.7, and 8.3% for fish fed control, 50, 100, and 250 μg AFB1 kg?1, respectively. This trial shows that AFB1 at a level of 50 μg AFB1 kg?1 and above can affect fish performance and disease resistance. Application of an effective mycotoxin management in the feed seems to be useful to prevent the negative effects of AFB1.  相似文献   

13.
The study was conducted to evaluate the effect of dietary lipid levels on growth, liver oxidative stress, and serum metabolites of juvenile hybrid snakehead (Channa argus × Channa maculata). Five isonitrogenous (crude protein 420 g kg?1) practical diets containing 58, 87, 115, 144, and 173 g kg?1 crude lipid (named L58, L87, L115, L144, and L173, respectively) were fed to triplicate groups of 30 fish (mean initial weight 24 g) for 8 weeks. The results showed that the final body weight (58.68–78.81 g), specific growth rate (1.41–1.75 % day?1), and protein efficiency ratio (1.66–2.64) increased significantly with the increasing dietary lipid levels. Liver lipid contents (71.65–101.80 g kg?1) and crude lipid (52.10–83.63 g kg?1) of whole body increased with increasing dietary lipid levels and reached the highest values in fish of L173. Fish of L173 showed lower alkaline phosphatase (23.81 King Unit gprot?1) and catalase activities (4.44 U mgprot?1) but higher malondialdehyde content (0.69 nmol mgprot?1) in liver than the other groups. Higher alanine transaminase activity (8.20 U L?1), aspartate transaminase activity (63.65 U L?1), and triglyceride (0.29 mmol L?1) in serum were observed in fish of L173 compared to the other treatments. Fish of L144 showed higher superoxide dismutase activity and glutathione peroxidase activities in liver than that of fish fed diet L58. Fish fed diet L58 showed lower total cholesterol (3.61 mmol L?1), high-density lipoprotein cholesterol (1.39 mmol L?1), and low-density lipoprotein cholesterol (0.46 mmol L?1) in serum. These results suggested that juvenile snakehead (Channa argus × Channa maculata) achieved good growth performance with dietary lipid level 173 g kg?1. Diet with 143 g kg?1 lipid was more conductive to liver health. The appropriate dietary lipid supplementation needs to be determined in further studies.  相似文献   

14.
The purpose of this study was to verify the effect of dietary Ca2+ on the growth and survival of silver catfish fingerlings (Rhamdia quelen) exposed to different water pH (5.5, 7.5 and 9.0). Silver catfish fingerlings were randomly placed in a thermoregulated water re‐use system with twelve 250 L‐tanks, two 1000 L‐biofilters and a 2000 L‐reservoir with a medium flow of 3.84 L min?1 tank. Stocking density was 0.16 fingerlings L?1. To prepare the treatment diets, the control diet (0.8 g kg?1 Ca2+) was supplemented with CaCO3 to yield experimental diets with 6.4, 9.5 and 23.9 g kg?1 Ca2+. There were three replicates/treatments. Survival was more than 93.9% in all treatments. Exposure of silver catfish fingerlings to alkaline or acid water reduced growth, and this effect was not ameliorated by dietary Ca2+ supplementation. Moreover, when fingerlings were maintained in water with pH 7.5, the best dietary Ca2+ range for silver catfish fingerling growth was 0.8–6.4 g kg?1.  相似文献   

15.
The anesthetic activities of the essential oils (EOs) of Hesperozygis ringens (EOHR) and Lippia alba (EOLA) and their effects in silver catfish (Rhamdia quelen) after anesthesia and recovery were investigated. Fish (32.19 ± 1.24 g) were submitted to one of the following treatments for each EO: basal group, control, or anesthesia (150, 300, or 450 μL L?1 EO). After that the anesthesia was induced or simulated and the biometric measurements were completed, fish were transferred to anesthetic-free aquaria to allow for recovery. Fish were sampled at 0, 15, 30, 60, and 240 min after recovery. At time 0 of recovery, the ventilatory rate was lower in the groups anesthetized with either EO. In comparison with the basal group, control fish showed an increase in plasma glucose, aspartate aminotransferase (AST), and Na+ levels and a reduction in Na+/K+-ATPase activity at 0 min of recovery. Plasma levels of ammonia and Na+ were lower in the fish anesthetized with EOLA (450 μL L?1) and EOHR (all concentrations), respectively, than in the control fish. Additionally, lactate, AST, alanine aminotransferase, K+ plasma levels, and gill Na+/K+-ATPase and H+-ATPase activities were higher in the fish anesthetized with either EOHR or EOLA than in the control fish. The EOs promoted slight changes in silver catfish that enabled both an adaptive response and the recovery of most of the measured parameters after 240 min regardless of concentration or EO that was used. These findings support the use of EOHR and EOLA as anesthetics for fish.  相似文献   

16.
The color of Undaria pinnatifida after boiling is an important factor determining its marketable value. Our previous study showed that decreased nutrients and elevated irradiance resulted in increases of lightness and yellowness (i.e., discoloration) of this alga. However, little is known about the optimal levels of nutrients and irradiance required to decrease these color values and the combined effects of these factors and boiling. We conducted two culture experiments to test the effects of nutrients (non-enriched and 1.25, 5, and 25% PESI enriched treatments), irradiance (0, 10, 30, and 180 µmol m?2 s?1), and boiling on lightness L*, redness a*, and yellowness b* of this alga. L* and b* did not differ between non-enriched and 1.25–5% PESI treatments, but were lower in the 25% PESI treatment. L* and b* were lowest at 0–10 µmol m?2 s?1, although negative growth occurred at 0 µmol m?2 s?1. Decreased irradiance had a positive or little effect on a* before boiling, but had a negative effect after boiling. These results suggest that around 25% PESI and 10 µmol m?2 s?1 were the optimal levels to decrease the three color values of this species after boiling.  相似文献   

17.
In this study, loach (Paramisgurnus dabryanus) were fed artificial diets containing 0.31 (control), 0.39, 0.48, 0.50 and 0.62 mg kg?1 of selenium (Se) for 60 days, respectively. Liver histopathology, hepatocyte ultrastructure, blood indices, biochemical parameters of liver functions and oxidative stress in the Se-treated loach were then assayed. The results showed the following: histopathological and ultrastructural lesions in liver were only observed in loach fed the 0.62 mg Se kg?1 diet; Haemoglobin and total protein were significantly increased in the 0.50 mg Se kg?1 group; albumin and high-density lipoprotein were increased significantly in the 0.48–0.50 mg Se kg?1 groups. However, white blood cell count was significantly decreased in the 0.48 mg Se kg?1 group; alanine aminotransferase, aspartate aminotransferase and lactate dehydrogenase were decreased in the 0.39–0.50 mg Se kg?1 groups. In liver tissue, the content of hydrogen peroxide was lower than that of controls in the 0.48–0.50 mg Se kg?1 groups, and the malondialdehyde level was lowest in the 0.48 mg Se kg?1 group. The activities of superoxide dismutase and glutathione peroxidase were significantly increased in the 0.50 mg Se kg?1 group; catalase and total antioxidant capacity were markedly increased in the 0.48–0.50 mg Se kg?1 group. These present results indicated that the dietary Se requirement for loach is 0.48–0.50 mg Se kg?1 diet.  相似文献   

18.
Feed requirements were estimated from specific growth rates in standardized soft tissue dry weight (SGRDW’) and atomic O:N ratios for mussels fed seven rations of microalgae (5–735 μg C h?1 ind?1) at 7 and 14°C respectively. The mean oxygen consumption and ammonia‐N excretion rates were significantly higher at 14°C (0.29 μg O2 and 27.3 μg N ind?1 h1) compared with those at 7°C (0.16 μg O2 and 11.4 μg N ind?1 h?1) (P < 0.05), resulting in O:N ratios between 3 and 45 at 7°C and 7 and 28 at 14°C. Low O:N ratios indicate protein catabolism and an unfavourable condition, whereas high ratios indicate that carbohydrate is the primary energy source. The measured SGRDW’ suggests minimum feed requirements of ~240 and ~570 μg C ind?1 h?1 for weight maintenance at 7 and 14°C, with corresponding O:N ratios of 24 and 16, respectively, indicating a more stressed condition at 14°C. A 0.5% SGRDW’ day?1 was obtained by ~565 (O:N = 29) and ~680 (O:N = 23) μg C ind?1 h?1 at 7 and 14°C respectively. A positive and significantly higher SGRDW’, with the lowest feed ration at 7°C compared with a negative SGRDW’ at 14°C (P < 0.05), indicated that storage time can also possibly be prolonged at low temperatures if the mussels are not fed.  相似文献   

19.
The effects of acclimation temperature (15, 20, 25 °C) on routine oxygen consumption and post-exercise maximal oxygen consumption rates (MO2) were measured in juvenile shortnose sturgeon (Acipenser brevirostrum LeSueur, 1818). The routine MO2 of shortnose sturgeon increased significantly from 126.75 mg O2 h?1 kg?1 at 15 °C to 253.13 mg O2 h?1 kg?1 at 25 °C. The temperature coefficient (Q 10) values of the routine metabolic rates ranged between 1.61 and 2.46, with the largest Q 10 values occurring between 15 and 20 °C. The average post-exercise MO2 of all temperature groups increased to a peak value immediately following the exercise, with levels increasing about 2-fold among all temperature groups. The Q 10 values for post-exercise MO2 ranged from 1.21 to 2.12, with the highest difference occurring between 15 and 20 °C. Post-exercise MO2 values of shortnose sturgeon in different temperature groups all decreased exponentially and statistically returned to pre-exercise (resting) levels by 30 min at 15 and 20 °C and by 60 min at 25 °C. The aerobic metabolic scope (post-exercise maximal MO2-routine MO2) increased to a maximum value ～156 mg O2 h?1 kg?1 at intermediate experimental temperatures (i.e., 20 °C) and then decreased as the temperature increased to 25 °C. However, this trend was not significant. The results suggest that juvenile shortnose sturgeon show flexibility in their ability to adapt to various temperature environments and in their responses to exhaustive exercise.  相似文献   

20.
Changes in semen quality and selected biochemical markers were analyzed during a week of spawning season of common carp Cyprinus carpio L. Semen was obtained twice, on May 30 and on June 7, and each time it was collected 24 h after hormonal stimulation using Ovopel [(d-Ala6, Pro9 NEt)-mGnRH + metoclopramide] in 1 pellet kg?1. The total volume of semen (ml), volume of semen per kg of body weight (ml kg?1 b.w.), sperm concentration (×109 ml?1), total number of sperm per kg of body weight (×109 kg?1 b.w.), pH of semen, pH of seminal plasma, seminal plasma osmotic pressure (mOsm kg?1) and the total protein content in seminal plasma (mg ml?1) were determined. A 10 mM Tris buffer containing 100 mM NaCl with 0.5 % BSA (pH 9.0, osmolality 200 mOsm kg?1) was used to activate sperm. The following computer-assisted sperm analysis (CASA) parameters were determined: percentage of motile sperm (MOT, %), progressively motile sperm (PRG, %), curvilinear velocity (VCL, μm s?1), straight-line velocity (VSL, μm s?1), movement linearity (LIN, %), wobbling index (WOB, %), amplitude of lateral head displacement (ALH, μm) and beat cross-frequency (BCF, Hz). The volume of semen per kg of BW, total number of sperm per kg of BW and semen pH were significantly lower at the second semen sampling compared to the first semen sampling. Volume of semen at the second sampling correlated positively with CASA parameters. A lack of differences among CASA parameters between both collection periods indicates good quality of carp sperm hormonally stimulated with Ovopel twice at a 1-week interval.  相似文献   

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