Effect of water temperature on the development of Portunus trituberculatus larvae in the off-season breeding mode (Decapoda, Portunidae)

What is it about?

To clarify the influence of different water temperatures on the development of Portunus trituberculatus larvae during off-season breeding, four temperature gradients of 27°C, 29°C, 31°C and 33°C were set up, and the effects of water temperature on larval development were systematically compared. The results showed that the moulting cycle from the zoaea 1 ~zoaea 2 stage was not significantly affected by water temperature (P > 0.05), remaining at approximately 3 d. However, in the Z2~megalopae stage, the MC in the 31°C group was consistently the shortest. The total developmental duration and total effective cumulative temperature during Z1~M in the 31°C group were the lowest at 9.97 d and 250 d·°C, respectively. As the water temperature increased, the survival rate (SR) of larvae at various stages gradually decreased, especially in the M stage, where the SR of the 33 °C group was only 2%, which was significantly lower than that of the 27°C and 29°C groups (P < 0.05). Among the antioxidant indexes, both SOD and T-AOC were the lowest in the 29°C group at 315.75 U/mg prot and 0.36 mmol/g prot, respectively, and both were significantly lower than those in the 33°C group (P < 0.05). In terms of digestive enzyme activity, except LPS, especially the activities of α-amylase (AMS), and cellulase (CL) in the 33°C group, which were significantly higher than those in the 27°C and 29°C groups (P < 0.05).

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