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Compensatory growth and body composition of juvenile Chinese sturgeon were investigated in indoor facilities at 19.0-22.3°Cafter food temporary deprivation under five feeding regimes: one group continuously fed and the other four groups were starved for 2, 4, 8 and 12 days, respectively followed by 16 days of re-feeding. During the starvation period, protein and lipid content of fish decreased slightly, while moisture and ash content of the starved groups became slightly higher compared to those of the control groups, with no significant differences. The hepatosomatic index (HSI) and the viscerosomatic index (VSI) for each test group (except s2) were significantly lower than that of the control groups. After re-feeding for 16 days, lipid content of fish increased significantly, while no significant differences were found in body biochemical composition, HSI and VSI comparing to the control groups. Final body weights and specific growth rates of s2, s4 were significantly higher than that of the control groups, showing over-compensatory growth; final body weights and specific growth rates of s8 were similar to the control groups, showing completely-compensatory growth; while the final body weights of s12 were lower than that of the control groups, with similar specific growth rates compared to the controls, showing partially compensatory growth. Food conversion efficiencies in groups S2 and s4 were significantly higher than that of the control groups; feeding rates of fish in group S8 and S12 were significantly higher than in the controls. We concluded that over-compensatory growth of S2 and S4 was acquired through raising food conversion rate, completely-compensatory growth of s8 and partially compensatory growth of s12 were acquired through increasing the feeding rate. [ABSTRACT FROM AUTHOR]

Thirteen polymorphic microsatellite markers were used to study the genetic variation of Ptychidio jordani sampled from the three sites of Liuzhou, Guiping and Yunan in the Pearl River Basin with the help of local fishers. Allele numbers ranged from 2 to 19 and fragment sizes ranged from 108 to 288. Average polymorphism information content (PIC), average observed heterozygosity (Ho) and average expected heterozygosity (He) were 0.439917, 0.4147 and 0.4986, respectively, which indicate a comparatively high level of genetic diversity. The coefficient of genetic differentiation ( Gst) between the two sub-populations ranged from 0.0074 to 0.0156, which shows little differentiation between sub-populations.amova analysis also offered evidence of weak differentiation with 0.53% variation between sub-populations, 99.47% variation within sub-populations and the Fst = 0.00531. The morphological variation among geographic sub-populations might result from different habitats. The correlation between genotype and morphological characters was analyzed and a significant correlation found between the genotype of microsatellite locus Hlj038 and the ratio of body depth and body length. The results suggest a possible linkage between this locus and these morphological characters. [ABSTRACT FROM AUTHOR]