Effects of Temperature on Artificial Breeding and Early Development of Osteochilus salsburyi

Abstract

To determine the optimal water temperature range for artificial breeding and early development of Osteochilus salsburyi, six water temperature gradients (14, 18, 22, 26, 30, and 34 °C) were set to systematically investigate the effects of water temperature on artificial reproduction efficiency, embryonic development, the morphology of newly hatched larvae, larval growth performance, and the timing of organ development in O. salsburyi. The results showed that the spawning induction rate of O. salsburyi reached 100% at 14–30 °C. The fertilization rate and hatching rate peaked at 18–22 °C, and no fertilization was completed at 34 °C. The malformation rates of embryos and larvae showed a U-shaped change, with the lowest malformation rate at 18 °C, and the teratogenic effect of high-temperature stress was more significant. The embryonic development rate was significantly negatively correlated with water temperature, and the development duration was significantly shortened with increasing water temperature. Embryonic development was arrested and all embryos died at 34 °C, while hatching could be completed at 14 °C but with an excessively long cycle. The morphological indicators of newly hatched larvae showed differentiated sensitivity to water temperature; total length, pre-anal length, and body height were highly sensitive indicators, and larvae exhibited balanced and robust morphological development at 18–22 °C. The larval survival rate first increased and then decreased with increasing water temperature, reaching the highest rate at 22–26 °C. The absolute growth increment, relative growth increment, and specific growth rate (SGR) continued to increase with increasing water temperature. The timing of larval organ differentiation and behavioral development was significantly advanced with increasing water temperature. Late organ development of larvae was blocked at 14 °C, only early development was completed at 34°C, and the internal and external organs of larvae developed completely and in an orderly manner at 18–30 °C. In summary, the optimal water temperature for artificial breeding and early development of O. salsburyi is 18–26 °C, among which 18–22 °C is the best for artificial reproduction and 22–26 °C is optimal for larval rearing. The results can provide a scientific basis for the precise regulation of water temperature in large-scale seedling production of O. salsburyi.

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