| Chinese mitten crab (Eriocherir sinensis) is one of the high economic value fishery animals in China. In the present study, characteristics of morphology and element accumulation were studied comparatively with Chinese mitten crab E. sinensis from different waters (Taihu Lake, Shijiu Lake and Gucheng Lake) in Jiangsu Province. A truss network of16distance measurements were measured within each individual in morphology study. At the same time, an Agilent7500ce inductively coupled plasma mass spectrometry (ICP-MS) was used to determinate the element concentration in the third pereiopod of the Chinese mitten crabs from the three lakes for element accumulation study. The distribution and concentration of major element calcium (Ca), magnesium (Mg) and phosphorus (P) in the exoskeleton of the crabs were measured using an JEOL8100electron probe microanalysis (EPMA). The patterns of morphological parameters and the element concentrations were further investigated by discriminant analysis in order to explore the method for geographical origin identification of Chinese mitten crab. Furthermore, the present study was initiated as a pilot study of the protection geographical origin of aquatic product.1. Morphological character study:One-way ANOVA analysis results showed that only K/A, P/A and Q/A have significant difference (p<0.05) among the crabs from the three lakes. By means of the least significant difference testing (LSD) multiple comparisons, significant difference were found for Q/A (p<0.05) and especially P/A (p<0.01) between the crabs from Taihu Lake and Shijiu Lake. Likewise, very significant difference (p<0.01) was found for K/A between the crabs from Taihu Lake and Gucheng Lake, for K/A, L/A and Q/A between the crabs from Shijiu Lake and Gucheng Lake. Moreover, three principal components were constructed for the three crab populations using Principal Component Analysis (PCA), and the contributory ratio of the first, second and third principal components were26.02%,15.46%, and11.31%, respectively, with a cumulative contributory ratio of52.79%. Also, the ratios of discriminant accuracy for the three crab populations were50%%、83.3%and70%, respectively, with a total discriminant accuracy of 69%. The above results suggested that the crabs from the three lakes could not be effectively characterized by the morphological measurements.2. Element environment fingeprint:Bioaccumulation of21chemical elements (Na, K, Ca, Fe, Mg, Sr, Ag, Al, As, Ba, Cd, Co, Cr, Cu, Mn, Mo, Ni, Pb, Se, T1, and Zn) were studied with the third pereiopods of E. sinensis crabs from the three lakes. The element Cr, Co, As, Se, Cd, Pb, T1, Ag, Mo, and Ni were not detected. One-way ANOVA analysis results showed that Na, Mg, Al, Ca, Mn, Cu, and Sr were significant difference (p<0.05) among the crabs from the three lakes. By means of the least significant difference testing (LSD) multiple comparisons, significant difference (p<0.05) were found for Al, Mn, Sr, and very significant difference (p<0.01) was found for Na, Mg, Ca, and Cu between the crabs from Taihu Lake and Shijiu Lake. Likewise, Cu was significant difference (p<0.05) and Al, Ca, Mn and Sr were very significant difference (p<0.01) between the crabs from Taihu Lake and Gucheng Lake. In addition, Na, Mg and Mn were very significant difference (p<0.01) between the crabs from Shijiu Lake and Gucheng Lake. Furthermore, in the principal component analysis (PCA) of the three populations, the contributory ratio of the first,the second and the third principal components were obtained as31.22%,21.58%,15.24%, respectively, with a cumulative contributory ratio of68.04%. The corresponding accuracy rates yielded by discriminant analysis were100%for crabs from Taihu Lake,80%for those from Shijiu Lake, and100%for those from Gucheng Lake, with a total discriminant accuracy of93.3%. The present study strongly suggests that the approach of the environmental fingerprints of elements in the third pereiopod of the crabs is potentially valid for geographical origin identification of Chinese mitten crabs.3. Element microchemistry analysis of exoskeleton:the exoskeleton of E. sinensis was found comprising three layers, i.e., the epicuticle, the exocuticle, and the endocuticle (from the external to the internal). Ca was the highest in exocuticle and the the lowest in inside of exocuticle. Mg was the highest in epicuticle and the lowest in exocuticle. In contrast, P was high in inside of epicuticle and endocuticle, but P in inside of epicuticle was higher than those in inside of endocuticle, in the carapace exoskeleton, and opposite in the claw exoskeleton. Ca and Mg were higher in the carapace exoskeleton than those in the claw exoskeleton. P in the inside of epicuticle was higher in the carapace exoskeleton than those in the claw exoskeleton and opposite in the inside of endocuticle. To compare the concentration in carapace exoskeleton, Ca was the highest in the crabs from Shijiu Lake population and the lowest in the crabs from Gucheng Lake. Mg was the highest in the crabs of Gucheng Lake and the lowest in crabs of Shijiu Lake. P in the inside of epicuticle was the highest in the crabs of Gucheng Lake and lowest in the crabs of Taihu Lake and P in the inside of endocuticle was highest in the crabs of Shijiu Lake and lowest in the crabs of Taihu Lake. Viewing from the element concentrations in claw exoskeleton, Ca was the highest in the crabs from Gucheng Lake and the lowest in the crabs from Taihu Lake. Mg was the highest in the crabs of Taihu Lake and the lowest in the crabs of Shijiu Lake. P was the highest in the crabs of Shijiu Lake and the lowest in the crabs of Gucheng Lake in the inside of epicuticle and wasthe highest in the crabs of Taihu Lake and the lowest in the crabs of Shijiu Lake in the inside of endocuticle. These results show that there were difference patterns of Ca, Mg and P deposition in exoskeleton among the Chinese mitten crab from three lakes, and the patterns are also potentially valid for future geographical origin identification. |
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