Development and characterization of a novel intergeneric hybrid grouper (Cromileptes altivelis ♀ × Epinephelus lanceolatus ♂)

Abstract

Distant hybridization often gives rise to offspring with hybrid vigor in plants and animals, and this method has also shown great potential in aquaculture. Grouper, an economically important marine species, has witnessed rapid growth in its related industry. To cultivate a new grouper variety with accelerated growth, superior meat quality, and high economic value, we successfully obtained fertilized eggs through artificial insemination, using humpback grouper (Cromileptes altivelis) as the maternal parent and giant grouper (Epinephelus lanceolatus) as the paternal parent. The hybrid groupers were successfully hatched and reared for up to 14 months. This study conducted comprehensive comparative analyses between the hybrid offspring and the parental species, focusing on embryo development, growth rate, morphological characteristics, chromosome karyotype and muscle nutrient composition. The hybrid grouper embryos completed their entire development, from fertilization to hatching, in an average duration of 20 h and 37 min, under controlled conditions of 28.5 ± 0.5 °C temperature and 28 part per thousand (ppt) salinity. Remarkably, the hybrid groupers exhibited significantly faster growth than humpback groupers, with an absolute weight growth rate 1.6 times higher. Additionally, the hybrid groupers displayed a 4.7% increase in meat yield compared to giant groupers. In terms of morphology, cluster analysis and principal component analysis were used to analyze the morphological framework data of the three grouper species, revealing that the hybrid groupers were more similar to giant groupers in their morphological framework. Chromosome karyotype and simple sequence repeats (SSR) analysis confirmed that the hybrid groupers have a total of 48 chromosomes, inheriting one set of chromosomes from each parent. This study provides a foundation for grouper hybrid breeding, and the hybrid groupers obtained in this research have the potential to become excellent commercial varieties.