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Xiao J.-X.,Zhejiang University | Zhou F.,Zhejiang Fisheries Technical Extension Station | Yin N.,Zhejiang University | Zhou J.,Zhejiang University | And 4 more authors.
Aquaculture Research | Year: 2013

An 8-week feeding trial was conducted to evaluate compensatory growth of juvenile black sea bream, Acanthopagrus schlegelii (initial weight 9.56 ± 0.12 g) in fifteen 300 L indoors flow-through circular fibreglass tanks. Feeding regimes was designed as follows: the control group (fed continuously), and S1, S2, S3 and S4 groups experienced 1, 2, 3 and 4 days of feed deprivation and then refeeding for the remaining days per week respectively. Changes in body weight, specific growth rate (SGR), feed intake (FI) and feed efficiency ratio (FER) were examined biweekly during the trial. At the end of the cyclical feeding periods, survival was not significantly affected by feeding strategy (P > 0.05). Final body weight of fish in S1 group was significantly higher than the control group (P < 0.05) after an 8 weeks trial, and fish in the S2 group reached the same body weight of the control fish (P > 0.05), however, the growth data in the S3 and S4 groups could not catch-up with the control treatment (P < 0.05). In the first 4 weeks, SGR values of fish with feed deprivation more than 2 days per week were inferior to those of control group (P < 0.05); however, no significant differences of SGR were observed among the groups for the last 4 weeks (P > 0.05). FI increased significantly with the starvation days increasing during the whole feeding trial (P < 0.05). At the periods 2, 4 and 6 weeks, FER values increased significantly with increasing feed-deprivation days up to S2 group and then levelled off (P < 0.05); however, FER in S2 group was only higher than that in S0 and S1, but no significant differences were found among the other treatments at the end of week 8. Significant differences were found in apparent digestibility coefficients (ADCs) of dry matter and crude protein among the treatments, while ADCs of crude lipid were unaffected. Protein and lipid contents in whole body and dorsal muscle showed declining tendency with increasing food deprivation days, while moisture contents tended to increase (P < 0.05). Serum parameters were markedly affected by feeding regimes except for total protein concentration and thyroxine level. The present results indicated that starvation for 1 and 2 days per week of juvenile black sea bream could achieve over-compensation and complete compensation respectively. However, in case of longer term feed restriction regime, fish failed to obtain good growth performance. © 2013 John Wiley & Sons Ltd. Source


Zhou F.,Zhejiang University | Xiong W.,Zhejiang University | Xiao J.-X.,Zhejiang University | Shao Q.-J.,Zhejiang University | And 3 more authors.
Aquaculture Research | Year: 2010

An 8-week feeding trial was conducted to determine the dietary arginine requirement of juvenile black sea bream Sparus macrocephalus in 18 350 L indoors flow-through circular fibreglass tanks. Six isonitrogenous and isoenergetic diets were formulated to contain graded levels of l-arginine (1.85%, 2.23%, 2.51%, 2.86%, 3.20% and 3.46% dry diet) from dietary ingredients and crystalline arginine. Each diet was randomly assigned to triplicate groups of 25 juvenile fish (10.51±0.15 g) twice daily (08:00 and 16:00 hours) to apparent satiation. Results showed that the specific growth rate (SGR) increased with increasing dietary arginine levels up to 2.51% and remained nearly the same thereafter. Feed efficiency ratio, protein efficiency ratio (PER) and protein productive value all showed an increasing tendency and then levelled off. Apparent digestibility coefficients of dry matter, crude protein and gross energy significantly improved up to 2.86% arginine diet and decreased at different extents thereafter. Fish fed 1.85% arginine diet had significantly lower protein content in the whole body and dorsal muscle than those fed diets supplemented with or >2.86% of arginine. Lipid content decreased and lower value occurred at 3.46% of dietary arginine. The dietary essential amino acid composition in the whole body of the black sea bream was significantly influenced by dietary arginine. Arginine retention increased with an increasing dietary arginine level from 1.85% to 3.20%, then declined slightly at 3.46% arginine diet. Serum biochemical parameters were significantly affected by the dietary arginine level except for the cholesterol content. Broken-line regression based on SGR and second-order polynomial regression based on PER indicated that the optimum dietary arginine requirements for juvenile black sea bream were 2.79% and 3.09% diet, corresponding to 7.74% and 8.13% of the dietary protein respectively. © 2010 The Authors. Aquaculture Research © 2010 Blackwell Publishing Ltd. Source


Zhang J.,Zhejiang University | Zhou F.,Zhejiang University | Wang L.-L.,Zhejiang University | Shao Q.,Zhejiang University | And 2 more authors.
Journal of the World Aquaculture Society | Year: 2010

An 8-wk experiment was conducted to determine the optimal protein requirement of juvenile black sea bream, Sparus macrocephalus, (initial weight 13.13 ± 0.21 g, mean ± SD) in 18 300-L indoor flow-through circular fiberglass tanks provided with sand-filtered aerated seawater. Six isoenergetic diets were formulated to contain varying protein levels ranging from 31.95 to 48.53% at about 3% protein increments by substituting corn oil and α-starch for fish meal. Each diet was assigned to triplicate groups of 20 fish in a completely randomized design. Twenty uniform-sized fish were stocked in a 300-L indoor flow-through circular fiberglass tank. After the feeding trial, weight gain and specific growth rate (SGR) increased with increasing levels of dietary protein up to 41.8% (P < 0.05) and both showed a declining tendency thereafter. Survival could not be related to dietary treatments. Both condition factor and protein efficiency ratio declined while dietary protein levels increased (P < 0.05). The highest and the lowest values of hepatosomatic index were found in fish fed 31.9 and 41.8% protein diets (P < 0.05), respectively, and showed no significant difference among other treatments (P > 0.05). Feed efficiency ratio (FER) improved as dietary protein level increased, with the maximum FER in the 41.8% protein diet, although this was not significantly different from the 45.2% protein diets. Apparent digestibility coefficients (ADCs) of main ingredients of diets tended to improve as the protein level increased, although they decreased to a different extent at higher levels of dietary protein. The highest ADC values of organic matter and protein were both found for fish fed 41.8% protein diet, while lipid and energy were at 38.5 and 45.2% protein diet, respectively. The whole-body protein content was positively correlated with dietary protein levels, while lipid content was negatively correlated. The muscle crude protein and crude lipid contents were significantly affected (P < 0.05) by dietary protein level, while moisture and ash showed no significant differences (P > 0.05). Dietary protein levels had significant influences on plasma parameters (P < 0.05). The concentrations of total cholesterol, triacylglyceride, alanine transaminase, and aspartate transaminase significantly reduced with dietary protein level except plasma total protein contents which presented reverse trend. Analysis of dose (protein level)-response (SGR) with second-order polynomial regression suggested that the optimal dietary protein requirement was 41.4%. © Copyright by the World Aquaculture Society 2010. Source


Zhou F.,Zhejiang University | Shao J.,Zhejiang University | Xu R.,Zhejiang University | Ma J.,Zhejiang University | Xu Z.,Marine Fisheries Research Institute of Zhejiang Province
Aquaculture Nutrition | Year: 2010

An 8-week feeding experiment was conducted to determine the quantitative l-lysine requirement of juvenile black sea bream Sparus macrocephalus (initial mean weight: 9.13 ± 0.09 g, SD) in eighteen 300-L indoors flow-through circular fibreglass tanks provided with sand-filtered aerated seawater. The experimental diets contained six levels of l-lysine ranging from 20.8 to 40.5 g kg-1 dry diet at about 4 g kg-1 increments. All the experiment diets were formulated to be isoenergetic and isonitrogenous. Each diet was assigned to triplicate groups of 20 fish in a completely randomized design. Weight gain and specific growth rate (SGR) increased with increasing levels of dietary lysine up to 32.5 g kg-1 (P < 0.05) and both showed a declining tendency thereafter. Feed efficiency ratio and protein efficiency ratio was poorer for fish fed the lower lysine level diets (P < 0.05) and showed no significant differences among other treatments (P > 0.05). All groups showed high survival (above 90%) and no significant differences were observed. The whole body crude protein and crude lipid contents were significantly affected (P < 0.05) by dietary lysine level, while moisture and ash showed no significant differences. The composition of muscle and liver also presented similar change tendency. Total essential amino acid and lysine contents in muscle both obtained the highest value when fish fed 32.5 g kg-1 lysine diet (P < 0.05). Serum protein, cholesterol and free lysine concentration were affected by different dietary treatments (P < 0.05), triacylglyceride and glucose contents were more variable and could not be related to dietary lysine levels. Dietary lysine level significantly affected condition factor and intraperitoneal fat ratio of juvenile black sea bream (P < 0.05) except for hepatosomatic index. There were no significant differences in white blood cell count and red blood cell count (P > 0.05), however, haemoglobin level was significantly influenced by different diets (P < 0.05). Analysis of dose (lysine level)-response (SGR) with second order polynomial regression suggested the dietary lysine requirement of juvenile black sea bream to be 33.2 g kg-1 dry diet or 86.4 g lysine kg-1 protein. © 2009 Blackwell Publishing Ltd. Source


He J.,Zhejiang Ocean University | He J.,Shanghai Ocean University | He J.,Marine Fisheries Research Institute of Zhejiang Province | Wu X.,Shanghai Ocean University | Cheng Y.,Shanghai Ocean University
Aquaculture | Year: 2016

Eriocheir sinensis, as an emerging aquaculture species, has become more popular in Chinese pond culture. However, high density stocking has usually caused high limb autotomy rate among juvenile crabs, and there are still very few reports about the effects of autotomy on both survival and growth rates in the juvenile E. sinensis. Therefore, we aimed at the effects of limb autotomy on the growth of E. sinensis through the individual cultivation method. The results showed that almost all injured juvenile crabs could feed and molt as normal crabs, and could manage to regenerate new limbs. The duration of the 1st molt had a negative correlation with the number of autotomized limbs. After the 2nd molt, the size of the new limb was comparable to that of the normal limb and the weight growth rate decreased with the increasing number of autotomized limbs. However, a positive correlation was found between the specific growth rate and the number of autotomized limbs during the 1st molting period. In this period, the feeding rate decreased slightly, and the crabs with more limb loss tended to have the lower feeding rates, but this had no significant difference (P > 0.05). Besides, feed efficiencies in experimental sets were slightly higher than the control, and those crabs that autotomized more limbs correspondingly had the higher feed efficiencies (P < 0.05). Meanwhile, the results also revealed that limb autotomy had no significant effects on the duration of the 2nd molting, the weight growth rate, the specific growth rate as well as the feeding rate in E. sinensis juveniles. Statement of relevance: Eriocheir sinensis, as one emerging aquaculture species, has become more popular in Chinese pond culture. However, the high culture density has usually caused a high rate of autotomy among the juveniles and there are still few reports on the effects of autotomy on the survival and growth rate in E. sinensis. The present study was to assess the effect of autotomy on the growth of E. sinensis such as the molting period, weight growth rate, specific growth rate, feeding rate as well as feed efficiency in E. sinensis juveniles, through the individual cultivation method. © 2016 Elsevier B.V. Source

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