Enhancing Early Larval Performance of Penaeus monodon Using Red Microalga Porphyridium cruentum in a Combined Diet Strategy

The effectiveness of Porphyridium cruentum, a red microalga, as an alternative live feed for black tiger shrimp (Penaeus monodon) larvae was evaluated through a series of laboratory experiments. In Experiment-1, ingestion rates were measured at the zoea-3 and mysis-2 stages with varying cell densities of P. cruentum (2,500; 5,000; and 7,500 cells/mL) over exposure periods of 1, 3, and 6 hours. Experiment-2 assessed larval performance from the nauplius stage to post larva-1 (PL-1) using P. cruentum at concentrations of 15,000; 30,000; and 45,000 cells/mL, both with and without artificial feed (AF). Experiment-3 explored the interaction of P. cruentum with certain diatom microalgae (Skeletonema costatum, Chaetoceros calcitrans, and Thalassiosira sp.) throughout the entire larval phase. All experiments employed a fully randomized design with three replications. The results showed that zoea-3 larvae had significantly higher intake rates than mysis-2. Larvae fed solely with P. cruentum at concentrations of 15,000 and 30,000 cells/mL were unable to progress to the PL-1 stage. The use of artificial feed or its combination with diatoms, particularly Thalassiosira sp., significantly (P<0.05) enhanced the larval stage index and survival rates. These findings suggest that P. cruentum is a viable complementary feed component in shrimp hatchery systems, especially when combined with other nutritional sources to improve larval performance and hatchery success.