Impact of sperm density on fertilization, hatching and emergence rate of hybrid yellow catfish "Huangyou-1" (<italic>Pseudobagrus vachelli</italic>♂ ×<italic>Pelteeobaagrus fulvidraco</italic>♀)

Abstract

In order to study the effects of different sperm densities of <italic>Pelteobagrus vachelli</italic> on the fertilization rate, hatching rate and emergence rate of hybrid yellow catfish Huangyou-1, this paper adopted 8 groups of different sperm densities (1×10³-1×10⁶ cells·mL^-1) to carry out artificial insemination experiments. The fertilized eggs were hatched under the same environmental conditions until the out-of-the-membrane fry developed and started to feed during the parallel swimming period. The hatching water temperature was (27±1) ℃ and each gradient was repeated in three groups.Results showed that when the sperm density increased from 1×10³ cells·mL^-1 to 2.5×10⁴ cells·mL^-1, the fertilization rate, hatching rate and emergence rate all increased significantly (<italic>P</italic><0.05); when the sperm density was 5×10⁴ cells·mL^-1, the fertilization rate reached the maximum value of (88.8±2.0) %; when the sperm density was 2.5×10⁴ cells·mL^-1, the hatching rate and emergence rate reached the maximum, respectively (83.4±2.8) % and (79.4±4.6)%. In addition, the regression equation was established to determine the relationship between sperm density and fertilization rate, hatching rate and emergence rate. In this experiment, 8 different sperm densities (1×10³-1×10⁶ cells·mL^-1) were used to artificially inseminate hybrid yellow catfish, and the optimal sperm density was determined. It is recommended that the sperm density range of 2.5×10⁴-5×10⁴ cells·mL^-1 should be used for artificial insemination in actual production. This density uses less sperm than in actual production, which can effectively protect male gamete resources and reduce the demand for cryopreservation of sperm during artificial seed production. The optimal sperm density selected in this experiment can be used as the best choice in large-scale production of hybrid yellow catfish, and it can also provide certain references for artificial insemination and hybrid breeding of yellow catfish.