SEMEN SUPPLEMENTED WITH ARGININE AND LEUCINE ON FERTILIZATION AND HATCHING OF HYBRID YELLOW CATFISH (TACHYSURUS FULVIDRACO)

In order to increase the reproductive efficiency of hybrid yellow catfish Tachysurus fulvidraco (♀)×Tachysurus vachelli (♂), the addition of two functional amino acids L-arginine (L-Arg) and L-Leucine (L-Leu) in sperm preservation solution was studied to find out the optimal concentration. The fertilization rate, hatching rate and malformation rate were used as factors to evaluate reproductive efficiency. Results showed that the fertilization rate increased first and then decreased with the fold increase in L-arginine concentration, and all of them were significantly higher than that of the control group (P<0.05). The highest fertilization rate was found in the 0.50 mmol/L concentration group, but there was no significant influence on the hatching rate and malformation rate (P>0.05). As the increasing of L-leucine concentration, the fertilization rate and hatching rate increased first and then decreased, while the malformation rate decreased and then increased, with the highest fertilization rate, the highest hatching rate and the lowest malformation rate in the 0.80 mmol/L concentration group, and all three evaluation factors were significantly improved in values when compared with the control group (P<0.05). We also tried to add the two amino acids simultaneously, at the concentrations of 0.4 and 1.0 mmol/L for L-arginine and L-leucine, respectively. We found that the fertilization rate, hatching rate and malformation rate were significantly improved (P<0.05). Besides, we examined sperm motility using a computer-assisted sperm analysis system (CASA), the results indicated that the addition of 0.4 mmol/L arginine and 1.0 mmol/L leucine, alone or simultaneously, significantly promoted sperm motility (P<0.05). Finally, an improved hatching bucket of Tachysurus fulvidraco was developed. It was proved to be more suitable for artificial breeding with the fertilization rate and hatching rate significantly higher than those of the traditional hatching bucket, by 12.13% and 20.76%, respectively (P<0.05), with the malformation rate significantly lower than the traditional hatching bucket (reduction of 6.42%; P<0.05). This study established a more efficient and convenient method for the artificial breeding of hybrid yellow catfish, which will help to promote the new species and accelerate the industrial development process.