Effects Of Bioactive Peptides Derived From Swine Blood On Antioxidant And Immune Function Of Jian Carp (Cyprinus Carpio Var. Jian)

With the intensification of aquaculture in China, there have been significant increases in various kinds of fish diseases. a large amount of chemicals and antibiotics have been used to control fish diseases, however the usefulness of antibiotics for infectious disease control has been challenged by its potential harm to the public health due to antibiotic resistance and residue problem, therefore there is an urgent need to search for alternatives. The present study aimed to evaluate the antioxidant and immunostimulating effects of peptides from swine blood (PSB) in fish through in vitro and in vivo studies, the results will provide solid evidence for the use of PSB to control fish diseases.1. In vitro study:The macrophages and the peripheral blood leukocytes were isolated from the head kidney and blood of carp through percoll gradient density centrifugation. The cells were cultured and treated with different concentrations of PSB(0,10,20,40,80μg/ml, the proliferation of the peripheral blood granulocytes, respiratory burst of macrophage and Superoxide dismutase(SOD) activity were analyzed. Result showed that proliferation of peripheral blood leukocytes after 24h incubation with 20、40 and 80μg/ml PSB were markedly stimulated. PSB at 40 and 80μg/ml could induce superoxide anion and NO in macrophages markedly. Moreover the SOD activity were evidently promoted in group treated with 80μg/ml PSB. The conclusion is that PSB could stimulate the proliferation and respiratory burst activities of the immune cells and hence modulate the non-specific immune responses in carp.2. In vivo study:PSB was added to the feed at the concentrations of 0,0.5,1,2,5g/ kg, blood samples and the liver tissue were collected at the end of week one, week two, week four and week eight. Serum and liver homogenates were prepared to detecte serum albumin(Alb), total protein(TP), superoxide dismutase (SOD), glutathione peroxidase (GSH-PX), alkaline phosphatase (AKP), catalase (CAT), interleukin (IL-1β), tumor necrosis factor (TNF-a), complement3 (C3), complement4 (C4), TLR-4. The results showed that after Jian Carps were fed with PSB, the content of Alb, TP, AKP, SOD, CAT, GSH-Px, IL-1β, TNF-a, C3 and C4 were increased in serum, PSB at 5g/kg significantly increased the antioxidant activity (P<0.05) and enhanced the contents of IL-1β, TNF-a, C3 and C4 in serum. with the increase of PSB, the TLR-4 content was also improved.Conclusions: PSB could stimulate the immune cells in vitro, enhance the antioxidant and immune function of jian carp.