Evaluation of Moringa oleifera and corn starch as feed for seed production of the pearl oyster Pteria sterna (Gould,1851)

Abstract

In the search for complementary diets to improve performance in bivalve farming, the use of terrestrial plants with nutritional and nutraceutical properties has been proposed as an alternative. The effectiveness of moringa leaf meal Moringa oleifera (Mo) was evaluated under controlled laboratory conditions (30 days), as a dietary supplement during the pre-growth stage of Pteria sterna seeds (7.2 ± 0.59 mm), as well as its combinations with microalgae and corn starch (Co), on growth and survival in the laboratory and its subsequent initial suspended culture in the sea. Diets were formulated with a mixture of the microalgae Tetraselmis suecica and Chaetoceros gracilis (M), diet M; M and 5% Mo (M + Mo); diet M and 5% corn starch (M + Co); 100% moringa leaf meal (Mo); 100% corn starch (Co), and diet M with 2.5% Mo and 2,5% Co (M + Mo + Co). The Mo diet did not provide pre-seed sustainability, resulting in 100% mortality at 30 days. From the rest of the diets, M obtained the lowest oyster survival, while M + Mo and M + Mo + Co showed the highest growth rates. At the end of the laboratory bioassay, the seeds were sown in a culture system in the open sea (50 days), where the highest growth occurred in the juveniles previously fed with M + Mo + Co. The results suggest that, in the nursery, P. sterna pre-seeds can be maintained with a diet of 100% corn starch, but not with 100% moringa flour, probably due to its poor digestibility. However, moringa used as an additive to the microalgae diet provided a higher yield in the oyster, which is reflected in a higher yield in the initial culture outdoors.