Verification of a hatchery protocol for green mussel Perna viridis spat production in the Philippines using industry-scale facilities

Hatchery seed production of mussels has been identified as a sustainable method to address the problem of low production due to insufficient seed supply. We conducted the first hatchery production trials of the Asian green mussel Perna viridis spats in the Philippines to demonstrate the feasibility of producing a sufficient and reliable seed supply for grow-out operations. However, results of small-scale experiments cannot be directly rolled-out commercially unless these are verified in bigger-scale facilities approximating those of commercial hatcheries. Thus, techniques on broodstock collection, spawning, and larval rearing, developed by the project in the laboratory during the experimental trials, were applied and verified in a production run using industry-scale tank facilities. Mature broodstocks collected from traditional mussel growing areas were successfully spawned in the hatchery. Eggs were fertilized, and these developed into D-hinged larvae, pediveliger, and metamorphosed into early spat before fully developing into the spat stage. Successful larval rearing up to the spat stage required the use of appropriate algal species and rates of feeding, close monitoring of larval stages, and water quality management. The survival from eggs to D-hinged larvae, D-hinged larvae to pediveliger, pediveliger to early spat, D-hinged larvae to early spat, and early spat (1 mm) to fully grown spat was 77, 64, 6.4, 3.1, and 72%, respectively. This study has established the feasibility of producing P. viridis in commercial-scale hatchery facilities

Proteus mirabilis (MJA 2.6S) from saline-tolerant tilapia exhibits potent antagonistic activity against Vibrio spp., enhances immunity, controls NH3\mathsf{NH_3} levels and improves growth and survival in juvenile giant tiger shrimp, Penaeus monodon

Online Version of Record before inclusion in an issue.Of several isolates from saline-tolerant tilapia exhibiting anti-vibrio activity, an isolate that demonstrated inhibitory activity with the biggest zone of inhibition against the shrimp pathogens, Vibrio harveyi and V. parahaemolyticus were chosen and investigated in this study. The isolate showed significant inhibition against the shrimp pathogens, V. harveyi and V. parahaemolyticus in a competitive assay. Upon 16S rRNA sequencing, the isolate was identified as putative Proteus mirabilis (MJA 2.6S). P. mirabilis (MJA 2.6S) exhibited extracellular protease, cellulase and amylase activities. Pathogenicity tests showed that it was not pathogenic to the shrimp even at the highest concentration of 108 CFU ml−1. Further, P. mirabilis (MJA 2.6S) improved growth and survival, stimulated higher phenoloxidase and bactericidal activities in the shrimp host and protected it from V. harveyi experimental infection. In addition, the isolate P. mirabilis (MJA 2.6S) significantly reduced the ammonia level of the pond water samples in vitro. Taken together, the results clearly showed the strong probiotic potential of P. mirabilis (MJA 2.6S) in shrimp and hence further studies are needed to determine its wider application as a probiotic in P. monodon culture