The effect of natural and artificial periphytic substrates with biofloc system on shrimp Penaeus vannamei (Boone 1931) culture: growth and immune response

A 120-day experiment was conducted to understand the growth and immunomodulatory response of Penaeus vannamei reared in biofloc-integrated periphyton system-like natural substrates like bamboo (NS1), sugarcane bagasse (NS2), artificial substrates like polyvinyl chloride mat (AS1), agricultural shed net (AS2), and a control group without biofloc and substrate. Experiments were carried out in 500-L fiber-reinforced plastic (FRP) tanks at a stocking density of 100 nos/m(3) (0.256 g). Shrimps reared in natural substrate-based treatments, (NS1 and NS2) recorded highest average body weight (ABW) and survival followed by artificial ones (AS1 and AS2), and were significantly higher (P < 0.01) compared with control. Significantly higher chlorophyll(a), ash-free dry matter (AFDM), and THB load were recorded in NS (1 and 2) followed by AS (1 and 2). Contrastingly, the Vibrio load was higher in control than treatments. Relative percentage survival was higher (P < 0.01) in treatments when challenged against V. parahaemolyticus. Serum protein level, phenoloxidase activity, and superoxide dismutase assay were significantly higher in natural and artificial substrate groups when compared to control. Immunomodulatory effects through immune gene study revealed a two fold to four fold upregulation in cytMn-SOD and mtMn-SOD genes in NS groups. Similarly, the lysozyme and prophenoloxidase genes were significantly upregulated in the treatment groups. The results conclude that biofloc with natural followed by artificial periphytic substrates were observed to deliver better performances, protective response, and immunomodulatory effects in pacific white shrimp P. vannamei culture.