| Summary: | 碩士 === 國立屏東科技大學 === 水產養殖系所 === 98 === This study was aimed to evaluate the effect of dietary supplement of hot-water extract (Eichhornia crassipes powder, EP 20; boiled E. crassipe powder, BEP 20; boiled E. crassipe supernatant extract, ESE 2 and boiled E. crassipe dreg extract ,EDE 18 g kg-1) of E. crassipes on immune responses, and resistance against pathogen Lactococcus garvieae infection of giant freshwater prawn Macrobrachium rosenbergii, after 0、1、2、4 months feeding scheme and sample measured. Immune factors including total haemocyte count, differential haemocyte count, phenoloxidase activity, respiratory burst, superoxide dismutase activity, glutathione peroxidase activity, and phagocytic activity and clearance efficiency to L. garvieae were assayed. In the immune experiments, diets containing BEP 20 and the ESE 2 g kg-1 showed significantly higher performance than that of the control group after the 1th month feeding; moreover, this phenomenon was observed even significantly higher in phenoloxidase activity, respiratory burst, superoxide dismutase activity, glutathione peroxidase activity, phagocytic activity and clearance efficiency in prawns fed E. crassipes supplemented diet than that of the control group in the 4th months. The challenge tests were conducted after 4 months feeding the diets containing different treatments of E. crassipes hot-water extract. The pathogen (L. garvieeae) were injected at 1 × 106 cfu prawn-1. The survival rate of prawn fed with E. crassipes hot-water extract supplement diet in each treatment group was significant higher than that of the control group in 48 hours, with significant results observed in BEP 20 g and ESE 2 g kg-1 feeding groups. Thus, prawn fed BEP 20 or ESE 2 g kg-1 of E. crassipes supplemented diet in the long term feeding scheme, could enhance their immunity and disease resistance toward L. garvieeae infection.
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