Brine Shrimp Feeding Contributes to Fast Growth and Enhanced Immune Capacity of Reattached Polyps of Scleractinian Coral Pocillopora damicornis

TL;DR

Feeding brine shrimp to reattached coral polyps boosts their growth and immunity, aiding reef restoration efforts.

Contribution

This study reveals how brine shrimp feeding enhances coral polyp growth and immunity through physiological and transcriptomic changes.

Findings

Brine shrimp feeding increases polyp diameter, new polyp numbers, and calcified skeleton weight.

Transcriptomic analysis shows activation of energy metabolism and biomineralization pathways.

Feeding reduces caspase-3 activation and boosts antioxidant capacity, improving immunity.

Abstract

The present study investigates how brine shrimp feeding contributes to the growth of newly reattached polyps of scleractinian coral Poccillopora damicornis. It was illustrated that polyp diameter, number of new polyps, weight of the calcified skeleton, symbiont density, chlorophyll a + c2 content and Ea values increased significantly after 60 days of brine shrimp feeding, and the immune capacity of the reattached polyps were also obviously elevated. These findings illuminate the molecular mechanisms mediating fast growth of coral polyps upon brine shrimp feeding, and shed light on the potential application of such methods in the cultivation of transplantation donors for reef restoration.

Reef restoration is the major way to compensate the loss of scleractinian corals, which requires huge amounts of transplantation donors. Previous study revealed that some species of corals can conduct polyp bailout and reattachment under environmental stress, which contributes to the living of coral communities and offer a novel way to produce numerous coral colonies for reef restoration. In the present study, physiological and transcriptomic approaches were conducted to illustrate the effects and molecular mechanisms of brine shrimp feeding on the newly attached polyps of coral Poccillopora damicornis. It was observed that brine shrimp feeding significantly prompted the growth of reattached polyps by elevating polyp diameter, number of new polyps, weight of the calcified skeleton, symbiont density, chlorophyll a + c2 content and Ea values. Transcriptomic analysis also inferred that signaling pathways responsive for energy metabolism, cell growth and biomineralization were dramatically activated. Furthermore, brine shrimp feeding enhanced the immunity of the reattached polyps by suppressing caspase-3 activation level and elevating antioxidant capacity. These results collectively reveals the influence and detailed molecular mechanisms of brine shrimp feeding on the growth of newly reattached coral polyps, which shed light on the potential application of such methods in the cultivation of coral transplantation donors.

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