|Abstract: ||白蝦 Litopenaeus vannamei（平均體重8.180.86 公克）連續21～ 28 天不餵食（飢餓），觀察其存活率、體重損失率、免疫因子、對溶藻弧菌（Vibrio alginolyticus）及白斑病毒（WSSV）的感受性，並檢測體內脂多醣與β 葡聚多醣結合蛋白（LGBP）、黏附蛋白（PX）、α2 巨球蛋白（α2-M）和辨識蛋白β（integrin β）的基因表現。結果顯示在飢餓7、14、21 及28 天的白蝦其存活率分別為100%、90%、71%及59%，體重損失率則分別為3.2%、7.3%、9.2%及10.74%。白蝦在飢餓1、1、1、5、14 及3 天，其透明球（HCs）、顆粒球（GCs，包括半顆粒球）、總血球數（THC）、酚氧酵素（PO）活性、呼吸爆（RBs）及過氧化酶（SOD）活性均明顯下降。白蝦在飢餓0.5~5 天後，辨識蛋白β 表現明顯下降，而在飢餓0.5~1 天後的LGBP、PX 及α2-M 則有增加的趨勢。所有的基因表現則在5 天後降至最低，第7 和14 天後恢復至原來的值。飢餓7 天的白蝦感染V. alginolyticus 及WSSV，發現累積死亡率於1~7 天與1~4 天後明顯高於一般餵食但感染弧菌及WSSV的白蝦。 白蝦經飢餓7 及14 天後，給予正常餵食（約體重的5%），分別在3、6 和12 小時，1、3 和5 天後檢測白蝦的免疫因子。結果顯示經過7天飢餓的白蝦在接受正常餵食5 天後，除了GCs 外，其他所有免疫因 子均恢復到基礎值，而經過14 天飢餓的白蝦，在接受正常餵食5 天後，所有免疫因子則無法恢復到基礎值。本研究證實飢餓7 天後的白蝦對病原菌感受性的增加，長時間飢餓(14 天)的白蝦呈現3 階段的基因表現調節模式，並伴隨著免疫因子的減少。|
Survival rate, weight loss, immune parameters, susceptibility against Vibrio alginolyticus and white spot syndrome virus (WSSV), and expression of ipopolysaccharide- and β-glucan-binding protein (LGBP), peroxinectin (PX), α2-macroglubin (α2-M) and integrin β were examined in white shrimp Litopenaeus vannamei (8.18 ± 0.86 body weight ) which had been devoid of food (starved) up to 21-28 days. Among the shrimp which had been starved for 7, 14, 21 and 28 days was 100%, 90%, 71%, and 59% survived, and they lost 3.2%, 7.3%, 9.2%, and 10.4% of their body weight, respectively. Hyaline cell (HCs), granular cells (GCs, including semi-granular cells), total haemocyte count (THC), phenoloxidase (PO) activity, respiratory burst (RB), and superoxide dismutase (SOD) activity significantly decreased in the shrimp which had been starved for 1, 1, 1, 5, 14 and 3 days, respectively. The expression of integrin β significantly decreased after 0.5~5 days of starvation, whereas expression of LGBP, PX, α2-M increased after 0.5~1 day. Transcripts of all genes decreased to lowest level after 5 days, and tended to background values after 7 and 14 days. Cumulative mortality rates of 7-days-starved shrimp challenged with V. alginolyticus and WSSV were significantly higher than those of challenged control-shrimp for 1~7 and 1~4 days, respectively. In another experiment, immune parameters of shrimp which had been starved for 7 and 14 days and then received normal feeding (at 5% of their body weight daily) were examined after 3, 6, and 12 h, and 1, 3, and 5 days. All immune parameters of 7-days-starved shrimp were able to return to baseline value after 5 days of re-feeding except for GCs, whereas all parameters of 14-days-starved shrimp failed to return to the baseline value even after 5 days of re-feeding. It was concluded that shrimp following 14 days of starvation showed three stages of modulation of gene expression, together with reduction in immune parameters, and decreased susceptibility against pathogens.