The role of sensory organs on the feeding activity of Penaeus vannamei under light and dark conditions

• Main Author: Noorsyarinah Sanudin
• Format: Thesis
• Language: English; English
• Published: 2015
• Subjects: SH365-380.92 Shellfish fisheries. Shellfish culture
• Online Access: https://eprints.ums.edu.my/id/eprint/38054/1/24%20PAGES.pdf; https://eprints.ums.edu.my/id/eprint/38054/2/FULLTEXT.pdf; https://eprints.ums.edu.my/id/eprint/38054/
• Institution: Universiti Malaysia Sabah

Penaeus vannamei is one of the important shrimp species in aquaculture. The use of light during the P. vannamei post larval rearing is not well documented. Thus different hatcheries applying different lighting conditions during the post larval rearing. This study was conducted to examine the effects of light or dark condition on the feeding activity and the effect of extended light or dark condition on the growth and survival of P. vannamei. To achieve these objectives, ingestion experiments were conducted using different sizes of shrimps; 0.5cm total length, TL (PLS), 1.0cm TL (PL10), 1.5cm TL (PL20) and 2.0cm TL (PL30) by providing them live or frozen Artemia under light or dark condition. After the ingestion experiment, the shrimps were preserved in Bouin's solution for histological observation of the eye and setae. Besides that, shrimps (1.0cm TLrvPL10) were subjected to different lighting conditions 24 hours light (24L), 24 hours dark (24D) and a natural diurnal cycle (12LD) to examine the effect of extended lighting conditions on the growth performance for three weeks. The ingestion experiments revealed that the 0.5cm TL shrimp showed high preference in ingesting frozen Artemia under light condition compared to dark condition. However, the ingestion of live Artemia showed no significant difference (P>0.05) under both lighting conditions. Histological observation showed that the optical properties of the 0.5cm TL shrimp comprises of crystalline cone, rhabdom and fasciculated zone. However, it was incomplete due to the lack of clear zone which indicates that the shrimps are unable to adapt to dark conditions. On the contrary, the ingestion rate of live and frozen Artemia under both lighting conditions by bigger sizes of shrimps (1.0, 1.5 and 2.0cm TL) showed no significant differences (P>0.05). Histological observation showed that shrimps from the size of 1.0cm TL (PL10) onwards, have a complete eye structure with the appearance of clear zone which indicates the ability of the shrimp to adapt in dark condition. The width of clear zone increased proportionally with the growth of the shrimps. Through setae observation, it was found that setae densities were different at each appendage of shrimp. The highest density of setae was recorded at the antennules while the lowest density at the antenna and nonchelae pereiopod. The setae density of the appendage did not increase with the shrimp size (0.5cm to 2.0cm TL) except at the maxilliped where increased of density was observed from 0.5cm TL to 1.5cm TL shrimp. Result of the rearing experiment, found that the shrimps were not affected by the extended period of dark or light condition as the growth, feed utilization and survival rate were not differed significantly ( P>0.05) among the treatments. Overall, this study found that 0.5cm TL shrimprvPLS depend more on the visual receptor in searching food. Providing the shrimps with frozen Artemia under dark condition minimized the function of the visual and mechanoreceptor. However, the ability of the shrimps (PLS-PL30) to detect food under these conditions indicating that other sensory organs are playing role in detecting food. In practical, this study would suggest that brighter condition to be used in the rearing of 0.5cm TL shrimp and from 1.0cm TL onwards ( >PL10) any lighting regimes can be used.