Dietary administration of Gracilaria tenuistipitata extract containing diets enhanced the immune response of white shrimp Litopenaeus vannamei and its protective effect against ammonia stress

• Main Authors: Chiew Siau Li, 丘曉莉
• Other Authors: Jiann-Chu Chen
• Format: Others
• Language: en_US
• Published: 2011
• Online Access: http://ndltd.ncl.edu.tw/handle/25508105569856957281

碩士 === 國立臺灣海洋大學 === 水產養殖學系 === 99 === Immune parameters such as haemogram, phenoloxidase (PO) activity, respiratory burst (RB), superoxide dismutase (SOD) activity, lysozyme activity and haemolymph protein were examined after the white shrimp Litopenaeus vannamei had been fed diets containing the hot-water extract of red alga Gracilaria tenuistipitata at 0, 0.5, 1.0 and 2.0 g kg1 for 7, 14, 21 and 28 days. These parameters increased directly with the amount of extract in diet. The haemocyte count, RB, SOD activity reached the highest levels after 14 days, whereas PO activity and lysozyme activity reached the highest levels after 28 days. In a separate experiment, L. vannamei which had been fed diets containing the extract for 3 weeks, were exposed to 5 mg l1 ammonia-N for 6, 12, 24, 72, 120 h. The immune parameters of shrimp exposed to ammonia-N dropped to the lowest in 6 h. The immune parameters of shrimp fed the extract-containing diets returned to the background value earlier, than did those of shrimp fed the control diet. Haemocyte count, PO activity and RB of shrimp fed 2.0 g kg1 diet returned to the background value after 24 h, 12 h and 6 h, respectively. The SOD activity and haemolymph protein of shrimp fed 2.0 g kg1 diet returned to the background value after 24 h. Lysozyme activity of shrimp fed 0.5, 1.0 and 2.0 kg1 diet returned to the background value after 12 h. In the challenged test, white shrimp L. vannamei which had been fed diets containing the extract after 2 weeks, were challenged with V. alginolyticus and WSSV at 2 × 106 cfu shrimp1 and 1 × 103 copies shrimp1, respectively, and then placed in seawater. The survival rate of shrimp fed the extract-containing diets was significantly higher than that of shrimp fed the control diet at 72-144 h post-challenge. It was concluded that L. vannamei fed the hot-water extract of G. tenuistipitata at 2.0 g kg1 or less showed increased immunity as well as protective immune response against ammonia stress, and increased resistance to V. alginolyticus and WSSV.