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.

Vitamin E requirements of juvenile grass shrimp, Penaeus monodon, and effects on non-specific immune responses.

A feeding trial was conducted to determine the dietary vitamin E (DL-alpha-tocopheryl acetate, dl-alpha-TOA) requirement and its effect on the non-specific immune responses of juvenile grass shrimp, Penaeus monodon. Purified diets with eight levels (0, 25, 50, 75, 100, 150, 200, 400 mg vitamin E kg diet-1) of supplemental dl-alpha-TOA were fed to P. monodon (mean initial weight 0.29 +/- 0.01 g) for eight weeks. Each diet was fed to three replicate groups of shrimp. Weight gains and total haemocyte count (THC) were higher (P < 0.05) in shrimp fed diets supplemented with 75 and 100 mg vitamin E kg diet-1 than in shrimp fed diets supplemented with

Increase of dietary vitamin C improves haemocyte respiratory burst response and growth of juvenile grass shrimp, Penaeus monodon, fed with high dietary copper.

Effects of dietary vitamin C (l-ascorbyl-2-monophosphate-Mg, C2MP-Mg) on growth, tissue copper (Cu) accumulation, and haemocyte superoxide anion production of juvenile grass shrimp, Penaeus monodon, fed with either adequate or high (8 x adequate) dietary Cu were studied. Three experimental diets were used: basal diet supplemented with adequate levels of both C2MP-Mg (40 mg kg diet(-1)) and Cu (20mg kg diet(-1)) (NC-NCu); basal diet supplemented with adequate C2MP-Mg and high Cu (8 x adequate) (NC-HCu); and basal diet supplemented with high C2MP-Mg (5 x adequate) and high Cu (HC-HCu). These were each fed to triplicate groups of shrimp (mean initial weight: 0.29+/-0.01 g) for 8 weeks. Highest (P< 0.01) weight gain, feed efficiency (FE) and protein efficiency ratio (PER) were observed in shrimp fed NC-NCu diet, intermediate in shrimp fed HC-HCu diet, and lowest in shrimp fed NC-HCu diet. Cu concentrations in hepatopancreas, muscle and haemolymph were highest in shrimp fed NC-HCu diet, followed by shrimp fed HC-HCu diet, and lowest for shrimp fed NC-NCu diet. Survival, total haemocyte count (THC) and intracellular superoxide anion (O-2) production were higher in shrimp fed NC-NCu diet than shrimp fed NC-HCu diet, whereas hepatosomatic index (HSI) was higher in shrimp fed NC-HCu diet than shrimp fed NC-NCu diet. However, all these parameters were similar in shrimp fed NC-NCu diet and shrimp fed HC-HCu diet. These data suggest that increase of dietary vitamin C improved haemocyte respiratory burst response and growth and prevented tissue Cu accumulation in P. monodon fed with high dietary Cu.

Dietary copper requirement of juvenile grass shrimp, Penaeus monodon, and effects on non-specific immune responses.

An 8-week feeding trial was conducted to determine the dietary copper (Cu) requirement and its effect on the non-specific immune responses of juvenile grass shrimp, Penaeus monodon. Purified diets with seven levels (0, 10, 20, 30, 40, 80, 160 mg Cu kg diet(-1) of supplemental Cu were fed to P. monodon (mean initial weight 0.29 +/- 0.004 g). Each diet was fed to three replicate groups of shrimp. The rearing water contained 1.53 microg Cu 1(-1). Shrimp fed diets supplemented with 10 and 20 mg Cu kg diet(-1) had significantly (P < 0.01) greater weight gain, feed efficiency (FE) and protein efficiency ratio (PER) than those fed the unsupplemented control diet and diets supplemented with > or = 40 mg Cu kg diet(-1). Whole body Cu concentration in shrimp generally increased as dietary Cu supplementation increased. Total haemocyte count (THC) was higher in shrimp fed diets supplemented with 10-30 mg Cu kg diet(-1) than shrimp fed the unsupplemented control diet and diets supplemented with > or = 40 mg Cu kg diet(-1). Intracellular superoxide anion (O2-) production ratios were significantly higher in shrimp fed diets supplemented with 10-30 mg Cu kg diet(-1) than shrimp fed the diet supplemented with 160 mg Cu kg diet(-1). Analysis by polynomial regression of weight gain percent, FE and by linear regression of the whole-body Cu retention of shrimp indicated that the adequate dietary Cu concentration in growing P. monodon is about 15-21 mg Cu kg diet (-1). The immune indicators suggest that an adequate dietary Cu concentration for non-specific immune responses in P. monodon is about 10-30 mg Cu kg diet(-1).

Dietary vitamin C and its derivatives affect immune responses in grass shrimp, Penaeus monodon.

Effects of L-ascorbic acid (AA) and its four derivatives, namely L-ascorbyl-2-sulfate (C2S), L-ascorbyl-2-polyphosphate (C2PP), L-ascorbyl-2-monophosphate-Na (C2MP-Na) and L-ascorbyl-2-monophosphate-Mg (C2MP-Mg) on the immune responses of juvenile grass shrimp, Penaeus monodon, were studied. The vitamin C deprived diet together with diets supplemented with either adequate or high (five times adequate) levels of AA, C2S, C2PP, C2MP-Na and C2MP-Mg were each fed to triplicate groups of shrimp (mean initial weight: 0.37 +/- 0.01 g) for 8 weeks. Significantly (P<0.01) higher weight gain (WG), feed efficiency (FE), survival, total haemocyte count (THC), superoxide anion (O2) production ratio and phenoloxidase (PO) activity were observed in shrimp fed diets supplemented with adequate and high levels of ascorbate than shrimp fed the vitamin C deprived diet, regardless of the ascorbate source. Among the ascorbate sources, shrimp fed C2MP-Mg and C2PP containing diets had higher THC than shrimp fed AA, C2S and C2MP-Na containing diets, regardless of the supplementation level. Shrimp fed adequate levels of C2MP-Mg and C2PP and high levels of C2MP-Mg containing diets had higher O2 production ratios than shrimp fed AA and C2S containing diets. Shrimp fed adequate levels of C2MP-Mg and C2PP and high levels of C2PP containing diets had higher PO activity than shrimp fed AA, C2S and C2MP-Na containing diets. These data suggest that dietary ascorbate enhances immune responses in P. monodon and different ascorbate sources may affect the immune responses differently.