Diet-driven transcriptional changes in weaning red abalone (Haliotis rufescens) and its hybrid (H. rufescens [♀] x H. fulgens [♂]).

The abalone (Haliotis sp) aquaculture industry is on the rise fueled by its high commercial demand. The use of abalone interspecific hybrids is gaining attention due to their improved growth and tolerance to environmental challenges. However, hybrids may respond differently to dietary inputs compared to their parental species, which could be optimized to achieve maximum growth potential. Accordingly, we previously reported that the postlarvae of a hybrid cross obtained by mating red and green abalone (H. rufescens [♀] x H. fulgens [♂]) presented higher growth and survival rates than red abalone postlarvae when fed with Macrocystis pyrifera (M) and a mixture of Ulva onhoi and Navicula incerta (UN). Here, to gain a deeper insight into the physiological and metabolic responses of both crosses, we report the results of a transcriptome sequencing analysis to unveil the diet-driven physiological changes within each cross. Our findings indicate that the diet induces modulation in the transcriptional machinery related to macromolecules breakdown, especially, the mixed diet UN induced higher expression of lysosomal enzymes, especially in enzymes involved in glycosaminoglycan catabolism, such as arylsulfatases, glucosidases, and alpha-fucosidases, which might indicate a higher ability to break down complex carbohydrates from algae. These transcriptional responses might explain the growth difference between pure and hybrid as well as for abalone fed with M and UN.