Ferritin administration effectively enhances immunity, physiological responses, and survival of Pacific white shrimp (Litopenaeus vannamei) challenged with white spot syndrome virus.

We examined the physiological (hemolymph glucose, lactate, and lipid) and innate non-specific immune responses (total hemocyte count (THC), phenoloxidase (PO) activity, respiratory bursts (release of superoxide anion, O(2)(-)) and superoxide dismutase (SOD) activity) to white spot syndrome virus (WSSV) in white shrimp (Litopenaeus vannamei) that were individually injected with 0.1, 0.5, and 1 ng g(-1) ferritin. Results showed that the THC, PO activity, and respiratory bursts of L. vannamei obviously increased (p < 0.05) 12 h after being injected with any dose of ferritin. However, the THC, PO activity, and respiratory bursts of L. vannamei that had received 0.5 and 1 ng g(-1) ferritin were significant higher than those of the other groups at 36-60, 60-72, and 36-60 h, respectively. SOD activities of L. vannamei 12 h after receiving 0.1, 0.5, and 1 ng g(-1) ferritin were significantly higher than those receiving saline. L. vannamei injected with ferritin at any dose maintained lower glucose, lactate, and lipid levels in response to WSSV challenge after 12-36, 24-48, and 36-60 h, respectively. The survival of shrimp that had received 0.5 and 1 ng g(-1) ferritin was significantly higher than that of shrimp that received saline and of control shrimp after 72 h. The ferritin messenger RNA transcripts of shrimp that had received 0.5 and 1 ng g(-1) ferritin were significantly higher than that of shrimp that received saline after 36 h. It was, therefore, concluded that the immune ability and resistance against WSSV infection increased in L. vannamei that had received > 0.5 ng g(-1) ferritin. Ferritin does play important roles in the innate immunity of the white shrimp. We observed higher SOD activities of L. vannamei that had received 0.1, 0.5, and 1 ng ferritin after 12 h than those that had received only saline (control), and the high SOD expression remained at the same levels even after 72 h of treatment.