Abstract: Taking 7month old carps as the objects, an acute and chronic salinity domestication experiment was conducted to study the carp 96 h semi-lethal salinity value and the changes of carp serum biochemistry and osmotic pressure in freshwater and at different salinities (3, 6, 9, 12, 14, and 16). The carp 96 h semi-lethal salinity value was 14.33 g·L^-1. In each salinity domestication group, the carp lactate dehydrogenase activity decreased after initial increase, and increased after an initial decreased again. The alanine aminotransferase and aspartate aminotransferase activities and the total protein and albumin contents were peaked at salinity 3, being significantly higher than those in freshwater (P<0.05), and then, followed by a downward trend. The blood content in each domestication group had a trend of increased after an initial decrease, but was significantly lower than that in freshwater group (P<0.05). The changes of urea content were more complicated, being significantly increased at salinity 3 (P<0.05), no significant difference in freshwater and at salinities 6 and 9 (P>0.05), and significantly increased with increasing salinity (P<0.05). With the increase of salinity, the serum osmotic pressure also presented an increasing trend, and was higher than that in freshwater (P<0.05). During the salinity domestication process, the carp osmotic pressure increased with the increase of environmental osmotic pressure. At the same time, due to the salinity change, the carp eat less, leading to the decrease of blood sugar content. The changes of each biochemical indicator showed that the carp was sensitive to the salinity change at the early stage of domestication. The fluctuation of serum urea content was caused by the functional change of the carp kidney induced by the salinity change.

Key words: Leymus chinensis, compensatory growth., saline-alkali stress, nitrogen allocation, clipping