Breeding Biology Research Of Pseudobagrus Ussuriensis

Pseudobagrus ussuriensis is one of the important breeding species because of its great economic value and better productive performance. Studies were carried out on Embryonic development, point of no return(PNR), Oxygen consumption rate, suffocation point and the acute toxicity of five kinds of commonly-used aquacultural drugs to Pseudobagrus ussuriensis through breeding biology angle. And discussed the influence of different feeding frequencies of growth performance through the research of different feeding frequency to Pseudobagrus ussuriensis ingestion, growth, fish biochemical index and enzymes activity. The results are as follows:1.Splitting methods of fertilized egg is discoidalcleavage,With the temperature increases, broken membrane time significantly reduce, while malformed rate is opposite, the best temperature for 25℃; Along with the increase of salinity, broken membrane time prolonged, hatch rates reduced, salinity should be controlled in 3.0 below; Too high or too low pH value lead to hatch rates lower, abnormal rates rise, the best pH value is 7.0～8.0; With the concentration of Cu²⁺, Zn²⁺, Cd²⁺, KMnO₄ and HCHO heighten, embryonic hatch rates declined, deformity rate and mortality are on the rise. Cu²⁺, Cd²⁺ and KMnO₄ is more toxic, concentration of 0.10mg / L, the embryo hatching rate was significantly lower than the control group.2. At the water temperature of 22～23℃condition, the maximum value of the initial feeding rate was100% in the seventh day after hatching. The PNR of larvae appeared on the 13th day after hatching; The suffocation point of Pseudobagrus ussuriensis was positively correlated with water temperature and negatively correlated with body weight; The average oxygen consumption rate of night (20:00 6:00) was 0.90±0.06 mg.g^-1.h^-1, while the day (8:00 18:00) Average oxygen consumption was 0.78±0.02 mg.g^-1.h^-1, There was a significant difference between day and night (p <0.05).3. At the Water temperature of 24～25℃condition, the safe concentration of CuSO₄+FeSO₄(Ratio5:2), KMnO₄, CuSO₄, HCHO and Nacl to Pseudobagrus ussuriensis was 0.34,0.24,0.27,4.03,1135.56mg/L, respectively. And the sensitivity sequence of five kinds of commonly-used aquacultural drugs was KMnO₄> CuSO₄> CuSO₄+FeSO₄(Ratio 5:2)> HCHO> Nacl.4. With the increasing of feeding frequency, the feeding rate(FR) of Pseudobagrus ussuriensis juveniles increased gradually. But when the feeding frequency arrived at three times daily, there was no significantly increasing on feeding rate with the increasing of feeding frequency. The Specific growth rate(SGR) increased first and then decreased. three times daily is the highest, but no significant different with two times daily (p> 0.05). There were significant changes in conversion efficiency(CE) too, the CE decreased with increasing feeding frequency. The best CE was achieved by feeding 0.5 time daily, significant different with other groups(p<0.05); Different feeding frequency had no effect on protein content(p> 0.05). With the increasing of feeding frequency, the moisture and ash content decreased gradually, while the lipid content increased, 0.5 time daily and 3 times daily group had significant differences (p<0.01); There were significant changes in protease, lipase and amylase. With the increase of feeding frequency, in addition to liver and pancreas protease activity was not significantly different, the other parts of the measured activities of digestive enzymes all decreased.