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Chinese Mitten Crab (chinese + mitten_crab)

Distribution by Scientific Domains

Earth and Environmental Science	70%

Selected Abstracts

Phylogenetic analysis of intestinal bacteria in the Chinese mitten crab (Eriocheir sinensis)

JOURNAL OF APPLIED MICROBIOLOGY, Issue 3 2007
K. Li
Abstract Aims:, To identify the dominant intestinal bacteria in the Chinese mitten crab, and to investigate the differences in the intestinal bacteria between pond-raised and wild crabs. Methods and Results:, The diversity of intestinal bacteria in the Chinese mitten crabs was investigated by denaturing gradient gel electrophoresis (DGGE) fingerprinting, 16S rRNA gene clone library analysis and real-time quantitative PCR. The principal component analysis of DGGE profiles indicated that substantial intersubject variations existed in intestinal bacteria in pond-raised crab. The sequencing of 16S rRNA genes revealed that 90,95% of the phylotypes in the clone libraries were affiliated with Proteobacteria and Bacteroidetes. Some genera were identified as unique in wild crabs and in pond-raised crabs, whereas Bacteroidetes was found to be common in all sampled crab groups. Real-time quantitative PCR indicated that the abundance of Bacteroides and the total bacterial load were approximately four-to-10 times higher in pond-raised crabs than in wild crabs. A significant portion of the phylotypes shared low similarity with previously sequenced organisms, indicating that the bacteria in the gut of Chinese mitten crabs are yet to be described. Conclusions:, The intestinal bacteria of pond-raised crabs showed higher intersubject variation, total diversity and abundance than that observed in wild crabs. The high proportion of the clones of Proteobacteria and Bacteroidetes in the clone library is an indication that these bacteria may be the dominant population in the gut of the Chinese mitten crab. Significance and Impact of the Study:, This study demonstrated obvious differences in the intestinal bacterial composition of pond-raised crabs and wild crabs. This knowledge will increase our understanding of the effects of aquaculture operations on bacterial community composition in the crab gut and provide necessary data for the development of probiotic products for crab cultivation. [source]

Kinetic analysis of oxytetracycline residues in Chinese mitten crab, Eriocheir sinensis, muscle following intramuscular administration

JOURNAL OF FISH DISEASES, Issue 8 2010
Q Feng
Abstract Crab culture is a very important economic industry in China. An epidemic of tremor disease of Chinese mitten crabs, Eriocheir sinensis, has become a serious problem in recent years. A spiroplasm has been proved to be the causative agent of this disease. Oxytetracycline (OTC) is used widely in aquaculture and was confirmed to be very effective against this pathogen. In this study, the distribution and depletion patterns of OTC in crab muscle were evaluated following single intramuscular doses of 2, 8 and 40 mg kg,1 body weight. OTC was detected with a validated HPLC method. Concentration,time profiles were well described by a three-compartment model with first-order absorption after a single dose of 8 and 40 mg kg,1. For comparison, a non-compartment model was employed. A withdrawal time of 48.29 and 55.92 days was suggested prior to consumption after receiving 8 and 40 mg kg,1. A recommended therapeutic dose of OTC in theory was calculated to be 36.37 mg kg,1. OTC was distributed well throughout the body. The elimination of OTC in muscle was slower compared with fish and other crustaceans. A dose of 40 mg kg,1 is suggested for practical use. [source]

Purification and characterization of a new reovirus from the Chinese mitten crab, Eriocheir sinensis

JOURNAL OF FISH DISEASES, Issue 12 2004
S Zhang
Abstract A new reovirus was recently isolated from a freshwater crab, the Chinese mitten crab, Eriocheir sinensis, in China. The complete viral particles are 55 nm in diameter, icosahedral, non-enveloped and have a mean buoyant density of 1.39 g cm,3 in CsCl gradient. The viral genome is composed of 12 pieces of dsRNA with an electrophoretic pattern of 3/4/2/3. This virus infects connective tissue of the gills, gut and hepatopancreas. Partial cDNA cloning and sequence analysis showed that the RNA-dependent RNA polymerase is located in the first RNA segment. From its biochemical, ultrastructural and physicochemical properties, this virus is quite different from the genus Aquareovirus (Reoviridae). It may represent a new genus of Reoviridae, different from the other crab reoviruses, P and W2. [source]

Effects of dietary protein level on growth, feed utilization and digestive enzyme activity of the Chinese mitten crab, Eriocheir sinensis

AQUACULTURE NUTRITION, Issue 3 2010
S. LIN
Abstract A feeding trial was conducted using isoenergetic practical diets to evaluate the effects of the dietary protein level on growth performance, feed utilization and digestive enzyme activity of the Chinese mitten crab, Eriocheir sinensis. Four experimental diets were formulated containing 250, 300, 350 and 400 g kg,1 protein and 16 kJ g,1 gross energy. Each diet was randomly assigned to triplicate groups of juvenile crab with mean initial body weight 3.56 ± 0.16 g and mean shell width 15.31 ± 0.06 mm. Juvenile crab were reared in indoor flow-through system consisting of 12 plastic tanks (1.0 m × 0.6 m × 0.5 m) and fed diets twice daily at 6,8% of body weight for 12 weeks. Performance was judged on the basis of growth (specific growth rate of weight, SGRG; specific growth rate of shell width, SGRSW), feed conversion ratio (FCR) and protein efficiency ratio (PER). A decreased FCR was observed with increasing dietary protein levels. Both SGRG and SGRSW significantly increased with increasing dietary protein levels up to 350 g kg,1, whereas there were no significant differences for protein levels from 350,400 g kg,1. Application of broken line regression analysis to SGRG provided an estimate of 347.8 g kg,1 dietary protein for maximal growth. The highest PER was observed in crab fed the diet containing 350 g kg,1 protein (P < 0.05). The percent survival was not affected (P > 0.05) by the different dietary treatments. No significant differences were observed in the apparent digestibility coefficients of crude lipid and dry matter among dietary treatments (P > 0.05). However, the apparent digestibility coefficients of crude protein and energy in crab fed different protein levels significantly increased with increasing dietary protein level (P < 0.05). Both amylase and protease activities in the intestine of E. sinensis were studied. The amylase activity decreased significantly (P < 0.05) with increased dietary protein level and protease activity increased. Regression analysis showed a negative effect of inclusion of dietary protein level on amylase activity (P < 0.05). However, protease activities were found to be positively correlated (P < 0.05) with dietary protein level. The protein content of the crab significantly increased with dietary protein levels up to 350 g kg,1 (P < 0.05), but no significant differences (P > 0.05) were founded with protein levels higher than 350 g kg,1. [source]

Effects of dietary phospholipid and highly unsaturated fatty acid on the gonadal development, tissue proximate composition, lipid class and fatty acid composition of precocious Chinese mitten crab, Eriocheir sinensis

AQUACULTURE NUTRITION, Issue 1 2010
X. WU
Abstract Precocious puberty is a major constraint to the economical rearing Eriocheir sinensis farming. Although dietary phospholipid (PL) and highly unsaturated fatty acids (HUFA) reportedly enhanced ovarian development in normal adult E. sinensis, it had opposite effects of reducing precocity in juveniles. This study investigated the effects of dietary PL and HUFA on survival, gonadal development and biochemical composition of precocious E. sinensis. Two diets with PL and HUFA supplementation (diet A) and deficient (diet B) were formulated and fed to precocious E. sinensis. Although no significant differences were found on survival and gonadosomatic index of crabs fed both diets, crabs fed diet B had significantly higher hepatosomatic index and hepatopancrean lipid content than crabs fed diet A. The percentages, 14:0, 18:1n-9, 20:5n-3 and 22:6n-3, in hepatopancreas, muscle and gonads were positively correlated to the diets. Interestingly, the crabs fed diet B accumulated significantly higher 18:2n-6 in gonads and muscle than those fed diet A. Furthermore, substantially higher 20:4n-6 was detected in the gonad and muscle than in the diets. These results suggested that dietary PL and HUFA had limited effects on male gonad biochemical composition. Meanwhile, the precocious E. sinensis may be capable of negating the negative effects of HUFA deficiency by enhanced tissue 18:2n-6 accumulation and converting 18:2n-6 to 20:4n-6. [source]