Effects of Fish Size and Water Temperature on the Acute Toxicity of Copper for Japanese Flounder,Paralichthys olivaceus,and Red Sea Bream,Pagrus major

The acute toxicities of copper were examined for Japanese flounder, Paralichthys olivaceus, and red sea bream, Pagrus major, in terms of fish size and water temperature. Artificial seawater of low pH of 5.4–6.7 was used as testing water to keep dissolved copper concentration at 0.04–41 mg Cu/L. Japanese flounder of 0.3–17 g and red sea bream of 0.5–13 g were exposed to different concentrations of copper for 96 h at 20 C under semistatic condition. Median‐lethal concentration for 96 h of Japanese flounder and red sea bream were 8.7–12.2 and 2.0–5.2 mg Cu/L, respectively. No significant relationships were observed between median‐lethal concentrations for 96 h and fish size for Japanese flounder, while the value decreased significantly with increasing fish size for red sea bream. Effect of water temperature on the acute toxicity was examined for Japanese flounder of 0.3 and 0.4 g at 10, 15, 20, and 25 C and red sea bream of 0.5 and 1.0 g at 12, 15, 20, and 25 C. Ninety‐six‐hour median‐lethal concentrations for Japanese flounder and red sea bream were 5.1–11.2 and 1.0–5.3 mg Cu/L, respectively. No significant relationships were observed between median‐lethal concentrations for 96 h and water temperature for both fish species.     

Methionine Requirement of Juvenile Japanese Flounder Paralichthys olivaceus

Abstract.— Growth studies were conducted to determine the dietary methionine requirement of juvenile Japanese flounder Paralichthys olivaceus . A basal diet was formulated to contain 50% crude protein from casein and gelatin, as intact protein sources, supplemented with crystalline L-amino acids (CAA), to correspond to the amino acid pattern found in the whole body protein of the juvenile Japanese flounder, except methionine. Test diets contained six graded levels of L-methionine 0.53, 0.83, 1.13, 1.43, 1.73, and 2.03% of diet (dry matter basis) or 1.06, 1.66, 2.26, 2.86, 3.46 and 4.06% of protein. To prevent leaching losses of water-soluble amino acids, CAA were pre-coated with carboxymethylcellulose (CMC), and diets were further bound with both CMC and κ-carrageenan after addition of the pre-coated CAA. Weighing about 2.80 g, each triplicate group of the juvenile flounder were fed test diets twice a day (5% of body weight) for 40 d. Survival rate, specific growth rate, feed conversion efficiency and apparent protein retention were significantly ( P < 0.05) affected by dietary methionine concentrations. The optimum dietary level of methionine in the presence of 0.06% of dietary cystine for Japanese flounder juvenile was estimated by using break point analysis. The values determined based on weight gain and feed efficiency were 1.49% of diet (or 2.98% of protein) and 1.44% of diet (or 2.88% of protein), respectively. These requirement values are close to the methionine level of flounder whole body protein.     

Dietary Soy Peptide Enhances Thermotolerance and Survival of Juvenile Japanese Flounder,Paralichthys olivaceus

Soy peptide (SP), a soy protein enzymatic hydrolysate, contains bioactive substances that could be utilized as an immune‐stimulating feed ingredient. The experiment evaluated the efficacy of dietary SP on promoting growth, and enhancing tolerance and survival to heat stress in juvenile Japanese flounder, Paralichthys olivaceus. Four diets were incorporated with different levels of SP (0, 2, 5, and 10%) and a 6‐wk feeding trial ensued. Following the feeding trial, the experimental groups were subjected to heat stress to measure survival rate and heat shock protein 70s (HSP70s) in gill, liver, and skin. Fish fed diets with SP inclusion showed considerable decrease in percent weight gain. Significantly higher lethal time values to 50% mortality (LT₅₀) value were recorded for fish fed 10% SP. Moreover, LT₅₀ values of fish fed 2 and 5% SP were significantly higher compared with fish fed control diet. HSP70s produced in all the tissues were significantly highest in fish fed 10% SP. HSP70s values were significantly higher in fish fed 2 and 5% SP compared with fish fed control diet. A significant reduction in HSP70s among all groups during recovery period was also observed. These results suggest that SP can be used to enhance the immune response and survival of P. olivaceus under heat stress.     

牙鲆仔鱼核酸与生长关系的研究

随机采取不同日龄健康的牙鲆仔鱼,用电子目镜和天平测定其全长（L）、体质量（m）,运用整体匀浆法测定鱼体中核酸和总蛋白浓度、RNA／DNA （a）比值和总蛋白／DNA比值（b）,研究了牙鲆仔鱼的生长,DNA、RNA和总蛋白的变化规律,探讨了核酸、总蛋白和生长的关系。试验结果表明,牙鲆仔鱼体质量、全长与RNA／DNA比值均呈线性负相关,关系式分别为 m＝-19．85 a＋82．79（r2＝0．89, P＜0．01）,L＝-7．41 a＋33．53（r2＝0．85,P＜0．05）。上述关系式说明,牙鲆仔鱼时期的生长以细胞增殖为主,大量消耗前期合成的蛋白质。牙鲆仔鱼体质量、全长与总蛋白／DNA 比值也呈线性负相关,关系式分别为 m＝-0．61 b ＋34．54（r2＝0．93, P ＜0．01）,L＝-0．22 b ＋15．33（r2＝0．86, P ＜0．01）。随着牙鲆仔鱼养殖日龄的增加,总蛋白／DNA比值下降的幅度大于RNA／DNA比值。核酸指标能从细胞水平上分析仔鱼的生长。     

Effects of Water Velocity on Growth Performance of Juvenile Japanese Flounder Paralichthys olivaceus

Critical swimming speed (Ucrit) of juvenile Japanese flounder Paralichthys olivaceus with 12.5-cm body length was determined to be 1.8-body lengthkec. A feeding trial was conducted to investigate the effects of water velocity on growth and other nutritional parameters of juvenile flounder (initial mean body weight: 5.7 g/fish), which is a sedentary species. The fish were raised in three water velocities, < 0.3 body length/sec (control), 0.9 body length/sec (slow) and 2.1 body length/sec (moderate), for 8 wk. Over the course of the feeding trial, the weight gain of the control, slow and moderate groups of fish were. 634%. 671% and 564%. respectively (significant between slow and moderate groups). A second order polynomial suggested that the optimum water velocity occurred at about 1.0 body length/sec. The feed efficiency of the moderate group (1.48) was significantly lower than those of the control (1.56) and slow (1.56) groups, while there were no significant differences in feed intake (1.72–1.75% of wet biomass) among the treatments. Water velocity did not affect the proximate composition of the whole body; however, rearing the fish at the moderate water velocity did slightly but significantly reduce protein retention. Lipid content of fin muscles was significantly different among the treatments: control (14.9%), slow (17.6%) and moderate groups (11.6%). Unlike salmonids, water current does not seem effective for improving growth and feed efficiency in juvenile Japanese flounder.     

Pharmacokinetics of Eugenol in Japanese Flounder,Paralichthys olivaceus

Eugenol, which has been used as an anesthetic for fish, was administered to Japanese flounder, Paralichthys olivaceus (127 ± 50.8 g), by bath treatment at concentrations of 0.025, 0.125, and 0.25 mL/L seawater for 10 min and intramuscular injection at 40 μL/fish to investigate the pharmacokinetic characteristics of eugenol in the plasma of Japanese flounder. In the bath treatment test, plasma eugenol concentration increased with increasing eugenol concentration up to 0.125 mL/L and reached steady state within 5 min. After a 10‐min bath treatment in 0.25 mL/L eugenol, plasma eugenol concentration was about 58.4 µg/mL. After transfer into running seawater, plasma eugenol concentration decreased biphasically with half‐lives of 0.0296 h (α‐phase) and 0.289 h (β‐phase). The AUC_0000→0800 was about 16.5 µg h/mL. In administration by intramuscular injection, plasma eugenol concentration increased rapidly after administration and decreased biphasically with half‐lives of 0.0329 h (α‐phase) and 8.08 h (β‐phase). The AUC_0000→0800 was about 52.5 µg h/mL. In both methods of administration, Japanese flounder with average weight of 127 g were effectively anesthetized when plasma eugenol concentrations were between 2.19 and 4.88 µg/mL.     

几种饵料对华贵栉孔扇贝浮游幼虫生长和成活率的影响

研究了湛江叉鞭金藻、亚心形扁藻、小球藻、干酵母、湛江叉鞭金藻与干酵母、湛江叉鞭金藻与亚心形扁藻对华贵栉孔扇贝幼虫生长和成活的影响。试验结果表明,投喂金藻和亚心形扁藻混合组生长速度最快,投喂金藻和酵母组次之,单独投喂小球藻和亚心形扁藻时生长速度最差。投喂酵母组成活率最高。     

Partial Replacement of Fish Meal with Corn Gluten Meal in Diets for Japanese Flounder Paralichthys olivaceus

Abstract.— Feeding experiments were conducted to evaluate corn gluten meal (CGM) as an alternative protein source for fish meal in the diet of Japanese flounder Paralichthys olivaceus . A diet containing 75% white fish meal as a sole protein source was the control, and 20, 40, and 60% of fish meal protein was replaced with CGM protein in the experimental feeds. Juvenile fish of about 8 g initial body weight were fed each diet to apparent satiation twice a day. 6 d per week for 8 wk at 20 C. Survival rates of fish ranged from 98 to 100% and were not significantly different ( P > 0.05) among treatments. Final body weight, weight gain, feed efficiency and protein efficiency ratio of fish fed the diets containing CGM up to 40% substitution levels were not statistically different from those of fish fed the control diet. All production parameters for fish fed the diet replacing 60% of fish meal protein were significantly lower than the control ( P ≤ 0.05). Supplements of crystalline amino acids to the CGM diet improved the nutritive value of the diet. Since substitution up to 40% did not adversely affect hematological and hematochemical parameters as well as whole body composition of the cultured fish, it is suggested that up to 40% of fish meal protein can be replaced with CGM in the diet of juvenile Japanese flounder.     

Effect of Restricted Feeding Regimes on Compensatory Growth and Body Composition of Red Sea Bream, Pagrus major

Compensatory growth of red sea bream, Pagrus major, during feed deprivation and after refeeding was investigated. Groups of three fish each were allocated into 28 cages. Fish were fed by a commercial feed to satiation twice a day. Four feeding groups of fish were prepared: one group with continuous feeding (C) for 9 wk and three other groups with feed deprivation for 1 wk (F1) in Week 3, 2 wk (F2) from Week 2 to Week 3, and 3 wk (F3) from Week 1 to Week 3, respectively. All fish in the feed deprivation treatments resumed feeding in Week 4. The full compensatory growth was achieved in F1 and F2 fish after refeeding for the first 3 wk but in F3 fish after refeeding for the second 3 wk. Specific growth rate and feed conversion efficiency in all fish experiencing fasting were higher than those of control fish after first 3 wk of refeeding. At the end of feed deprivation in Week 3, crude protein, crude lipid, and energy content of all fish experiencing fasting were lower than those of the control fish. These results indicated that red sea bream experienced 1‐, 2‐, and 3‐wk fasting could achieve full compensatory growth in the 9‐wk feeding trial.     

Effects of Dietary Protein and Lipid Levels on Growth and Body Composition of Juvenile Japanese Flounder,Paralichthys olivaceus,Fed Diets Containing Intact Proteins or Crystalline Amino Acids

Abstract

The influence of eight semi-purified diets having different protein and lipid levels on growth performance and body composition of Japanese flounder, Paralichthys olivaceus, was evaluated. The sources of protein were either intact protein (IP) or a mixture of IP and crystalline amino acids (CAA). In trial 1 (IP group), four test diets were prepared from IP sources (casein-gelatin) with combination of two protein levels (35% and 50%) and two lipid levels (10% and 20%). In trial 2 (PA-group), another four test diets were formulated using IP and CAA with combination of the same two protein and two lipid levels as used for trial 1. The juveniles (about 2.00 g initial weight) were fed the respective test diets for 42 days in duplicate tanks. In both trials, weight gain was the highest for juveniles fed the diet containing 50% protein with 10% lipid and the lowest in those fed the 35% protein with 10% lipid diet. Weight gain of juveniles was significantly increased when the lipid levels were increased in low protein (35%) diets for both trials. In high protein (50%) diet, however, increase lipid levels from 10 to 20% with 50% protein resulted in decrease in weight gain, irrespective of protein sources. Specific growth rate, feed intake, feed conversion efficiency were significantly affected by different dietary protein and lipid level. Content of neutral lipids in the whole-body particularly, triglycerides was statistically higher for fish fed the high-lipid diets than those fed the low-lipid diets irrespective of protein sources. But, polar lipid did not show any differences either for different protein or lipid levels. Level of individual amino acids in the whole-body showed little difference among the dietary treatments. Results suggest that Japanese flounder grew better on low lipid level with 50% protein-based diets and supplementation of CAA did not show any adverse effect on the growth performance with different levels of protein and lipid in the diets.     

甲氧苄氨嘧啶在牙鲆体内的药代动力学研究

健康牙鲆口服剂量为100 mg/kg的甲氧苄氨嘧啶后,利用高效液相色谱测定药物在牙鲆肌肉、血液、肾脏、肝脏质量浓度变化,并通过3P87药动学软件分析数据。试验结果表明,甲氧苄氨嘧啶在肌肉、血液、肾脏、肝脏4种组织中均符合一级吸收二室开放模型,其在上述4种组织中的达峰时间(tmax)分别为18.72、12.942、3.13 h和19.49 h;达峰质量浓度分别为13.80、18.23、32.79、27.40μg/ml;消除半衰期分别为23.64、21.471、6.72 h和15.99 h。口服甲氧苄氨嘧啶,在牙鲆体内吸收与消除较慢,血药浓度高,维持时间长。     

Compensatory Growth of Olive Flounder,Paralichthys olivaceus,Fed the Extruded Pellet with Different Feeding Regimes

This study was performed to determine compensatory growth of juvenile olive flounder fed the extruded pellet (EP) with different feeding regimes. Seven treatments with triplicates of different feeding regimes were prepared; α fish was daily fed for 6 d a week throughout 8 wk (8WF); α fish was starved for 1 wk and then fed for 3 wk twice [(1WS + 3WF) × 2]; β fish was starved for 2 wk and then fed for 6 wk (2WS + 6WF); χ fish was starved for 5 d and then fed for 9 d four times [(5DS + 9DF) × 4]; δ fish was starved for 10 d and then fed for 18 d twice [(10DS + 18DF) × 2]; δ fish was starved for 2 d, fed for 5 d, starved for 3 d, and then fed for 4 d four times [(2DS + 5DF + 3DS + 4DF) × 4]; and φ fish was starved for 4 d, fed for 10 d, starved for 6 d, and then fed for 8 d twice [(4DS + 10DF + 6DS + 8DF) × 2], respectively. Total feeding day was all same, 36 d except for control group (48 d). Weight gain of flounder in the 8WF treatment was higher than that of fish in other treatments. And weight gain of flounder in the 2WS + 6WF treatment was higher than that of fish in the (5DS + 9DF) × 4 and (4DS + 10DF + 6DS + 8DF) × 2 treatments. Feed consumption of flounder in the 8WF treatment was higher than that of fish experienced feed deprivation. Feed efficiency ratio (FER), protein efficiency ratio (PER), and protein retention (PR) were not significantly different among treatments. Chemical composition of the whole body of fish with and without liver, except for moisture content of liver, was not different among treatments. T₃ level of fish in the 8WF and 2WS + 6WF treatments was higher than that of fish in the (5DS + 9DF) × 4 treatment. It can be concluded that juvenile olive flounder achieved better compensatory growth at 6‐wk refeeding after 2‐wk feed deprivation compared with that of fish with different feeding regimes. And T₃ level of fish seemed to partially play an important role in achieving compensatory growth.     

不同摄食水平对牙鲆幼鱼生长及能量收支的影响

在水温(20.0±0.5)℃,摄食水平分别为体质量的1.0%、1.5%及饱食条件下,进行牙鲆幼鱼[体质量为(35.08±0.05)g]的生长和能量收支的研究。试验结果表明,随着摄食水平的增加,鱼体干物质、蛋白质和能量表观消化率随摄食水平的增加而增加;湿质量特定生长率随摄食水平的增加呈线性上升,干物质、蛋白质和能量特定生长率呈对数增加;饲料湿质量转化效率不受摄食水平的影响,饲料干物质、蛋白质和能量转化效率随摄食水平的增加先升后降。粪能占摄食能的比例随摄食水平的增加而显著降低,生长能占摄食能的比例随摄食水平的增加先升后降,代谢能占摄食能的比例变化与生长能占摄食能的比例变化相反。各个摄食水平下能量收支式为:1.0%:100.00C=28.99G+2.34F+6.03U+62.64R;1.5%:100.00C=37.19G+1.94F+5.27U+55.60R;饱食:100.00C=30.73G+1.36F+5.16U+62.75R。     

Reevaluation of the Dietary Protein Requirement of Japanese Flounder Paralichthys olivaceus

An experiment was conducted to determine the dietary protein requirement by different analysis methods and to study the effects of dietary protein levels on growth performance and body composition in Japanese flounder Paralichthys olivaceus fed white fish meal and casein-based diets for 8 wk. After a 1-wk conditioning period, one of six isocaloric diets containing 30, 36, 42, 48, 54, and 60% crude protein (CP) was fed to fish at approximately 4–5% of wet body weight on a dry matter basis to triplicate groups of 15 fish averaging 13.3 ± 0.06 g (mean ± SD). After 8 wk of the feeding trial, weight gain (WG) and feed efficiency (FE) from fish fed 48% CP diet were similar to those from fish fed 42% and 54% CP diets, and were significantly higher than those from fish fed 30, 36 and 60% CP diets ( P < 0.05). Fish fed 48 and 54% CP diets had a significant higher specific growth rate (SGR) than did fish fed 30 and 36% CP diets ( P 0.05). Protein efficiency ratio (PER) was inversely related to the dietary protein level. No significant differences existed in hematocrit (PCV) and survival rate among the dietary treatments. Broken-line model analysis indicated that the optimum dietary protein level could be 44.0 ± 3.0% for maximum WG in Japanese flounder. Polynomial regression analysis of the dose-response showed that maximum WG occurred at 50.2% ( R² = 0.94) based on WG, and the second-order polynomial regression analysis with 95% confidence limits revealed that the range of minimum protein requirement was between 38.9% and 40.3% based on WG. Therefore, these findings suggest that the optimum dietary protein requirement for maximum growth of Japanese flounder is greater than 40%, but less than 44% CP in the fish meal and casein-based diets containing 17.0 kJ/g of energy.     

Supplementations of dl‐Methionine and Methionine Dipeptide in Diets are Effective for the Development and Growth of Larvae and Juvenile Red Sea Bream,Pagrus major

Growth trials for larvae and juvenile red sea bream, Pagrus major, were conducted to elucidate the efficacy of two molecular forms of methionine; dl ‐methionine (dl ‐Met) and methionine dipeptide (Met‐Met). For the larvae experiment, five experimental diets were formulated and fed to fish (42 mg) for 30 days. A diet which has 15% soy protein isolate served as the control diet. Similarly, test diets supplemented with dl ‐Met and Met‐Met at 0.5%, which were either precoated by zein or intact, were also formulated. For the juvenile experiment, five experimental diets were formulated wherein the control diet contained 25% soy protein isolate. Test diets were supplemented with dl ‐Met and Met‐Met at 0.75%, which were either coated by carboxymethycellulose or intact and fed to juveniles (0.75 g) for 56 days. The results of two feeding trials showed both dl ‐Met and Met‐Met can be equally utilized by red sea bream larvae and juveniles. Coating the amino acid significantly improved both fish larval and juvenile growth performance. The development of digestive protease activity of larvae was significantly influenced by coating the amino acid, but the type of methionine was not a factor in changing the protease activity of larvae.     

无公害工厂化养殖牙鲆技术研究

按照水产品无公害养殖行业标准，在工厂化条件下进行牙鲆养殖研究，经1年试验，平均规格401g／尾，成活率为51．4％。饵料系数1．93，饵料效率0．52。     

Diel Variation in RNA/DNA Ratios of Japanese Flounder Paralichthys olivaceus

Laboratory-reared Japanese flounder Paralichthys olivaceus larvae (11.2 ± 0.2 mm total length; age 26 d) were sampled over a 48-h period to determine any diel patterns in RNA/DNA ratios. RNA/DNA ratios were highest during daytime periods (0800, 1100, 1400, 1700, 2000 h) and significantly reduced at night (2300, 0200, 0500 h). Findings from this study indicate a diel variation in biochemical condition and suggest that special care should be taken in sampling design and data analysis to account for this source of variability.     

微生态制剂对牙鲆幼鱼脂肪酶的影响

试验结果表明,微生态制剂可提高牙鲆幼鱼消化道的脂肪酶活性,微生态制剂的使用方式和使用的间隔时间影响其使用效果。拌饲投喂与在水中同时使用微生态制剂,在7 d内使脂肪酶活性大大提高,但随后采用这种使用方式的试验组脂肪酶活性又迅速降低。而只在水中使用微生态制剂的各试验组的脂肪酶活性却随着试验的进行,逐步提高。有利于脂肪酶活性提高的最佳方案是只在水中使用微生态制剂,使用间隔时间为7 d,芽孢杆菌∶乳酸菌为10∶1,菌液密度为105/m l。     

Effect of Dietary Inclusion of Blue Mussel Extract on Growth and Body Composition of Japanese Flounder Paralichthys olivaceus

Dietary inclusion of a water-soluble fraction of blue mussel Mytilus galloprovincialis was examined as a feeding stimulant for juvenile Japanese flounder Paralichthys olivaceus . The control diet mainly consisted of fish meal, potato starch, and pollack liver oil. Five, 10, and 20% (weight/weight) of the control diet was exchanged with aqueous extracts of blue mussel meat in experimental groups. Fish of about 10 g in initial body weight were fed each diet to satiation, twice daily, 6 d per wk for 6 wk at 20 C. The final body weight, weight gain, and feed efficiency of fish fed the diets containing blue mussel extracts were significantly higher than those of fish fed the control diet. However, these parameters were not different among experimental groups containing blue mussel extract independent of the inclusion level of extract. A similar trend was shown in protein efficiency ratio as fish fed the control diet had a significantly lower protein efficiency ratio than the other dietary groups. Compared to the control diet, higher plasma protein and lower triglyceride were found in fish fed the diets with the extract, while other blood constituents were relatively similar for the dietary groups tested. On the other hand, whole-body crude lipid content and lipid retention of fish fed the diets with the extract were generally significantly higher than those of fish fed the control diet. Whole body crude protein was identical regardless of the dietary composition; however, protein retention of fish showed a similar trend to lipid retention.     

循环养殖系统中牙鲆生长及营养盐状况研究

研究了一个包括鱼池、沉淀池、硝化滤器和大型海藻滤器的循环养殖系统长期运行的水质状况及养殖牙鲆的生长状况。报道了该系统中的牙鲆在一定时间内的生长情况,建立了牙鲆体重(抽样平均湿重)与生长时间的回归方程:W=4.654 e0.0181 t。同时监测系统中的NH4 -N、NO2--N、NO3--N、PO43--P浓度,其NH4 -N在实验时间内一直保持在0.4 mg/L以下,NO2--N低于0.2 mg/L以下,NO3--N、PO43--P在开始时有一定积累,后来有下降趋势。实验表明,该循环养殖系统可以满足牙鲆工厂化循环养殖的要求。