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Juvenile Black Sea Bream (juvenile + black_sea_bream)

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Earth and Environmental Science	100%

Selected Abstracts

Quantitative l -lysine requirement of juvenile black sea bream (Sparus macrocephalus)

AQUACULTURE NUTRITION, Issue 2 2010
F. ZHOU
Abstract 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. [source]

Optimum arginine requirement of juvenile black sea bream, Sparus macrocephalus

AQUACULTURE RESEARCH, Issue 10 2010
Fan Zhou
Abstract 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. [source]