Changes in water temperature: The effect of triploid performance in Pacific abalone (Haliotis discus hannai)

The triploid Pacific abalone (Haliotis discus hannai) has significant economic value and promising application prospects. However, the optimal cultural conditions that maximize the advantages of triploidy in the abalone have yet to be determined. This study examined the properties of triploid Pacific abalone after 3 months of culture under three constant temperatures (18 degrees C, 22 degrees C, and 26 degrees C) to fill up this information gap. The results showed that the survival rate of triploids in the 26 degrees C group was significantly higher than that of diploids (P < 0.05), while the survival rate of triploids in the other two groups was similar to that of diploids (P > 0.05). Except for the shell width of the 22 degrees C group and the shell length of the 26 degrees C group, triploid Pacific abalone exhibited significantly superior growth traits compared to diploids at all temperatures (P < 0.05). The most notable improvement was observed in the foot muscle weight trait, where there were triploid advantage rates of 81.44% (18 degrees C), 76.21% (22 degrees C), and 54.96% (26 degrees C). The specific growth rate and the ratio of shell length and body weight indicated that triploids grew the fastest in the 22 degrees C group. Furthermore, the thermal resistance of diploids and triploids was evaluated through the Arrhenius break temperature (ABT) of cardiac performance. The results demonstrated that the ABT of triploids was significantly higher than that of diploids (P < 0.05, ABT(2N) = 30.81 +/- 0.43 degrees C, ABT(3N) = 31.38 +/- 0.72 degrees C). Both diploid and triploid foot adhesion forces were measured, and the results showed that triploid foot adhesion force was stronger than that of diploids (P < 0.05). Additionally, there was a significant positive correlation between foot adhesion force and meat yield traits (foot muscle weight, fullness index (FI) and foot muscle-soft tissue index (FMSI)) (P < 0.05). In summary, this study confirmed the triploid advantage in meat yield of Pacific abalone and identified a temperature range that maximizes their growth rate. Moreover, triploids exhibited improved thermal resistance and adhesion capacity compared to diploids, with an increase in meat yield. The results of this study could serve as a reference for identifying a culture model suitable for triploid Pacific abalone and thus could promote the development of the triploid aquaculture industry.