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To investigate the influence of sodium to potassium(Na/K) ratios on the growth performance and physiological response of the Pacific white shrimp( Litopenaeus vananmei), various concentrations of KCl were added to low-salinity well water(salinity 4) in an 8-week culture trial. Six treatments with Na/K ratios of 60:1, 42:1, 33:1, 23:1, 17:1, and 14:1 were replicated in triplicate. The highest weight-gain rate(3 506±48)% and survival rate(89.38±0.88)% was observed in well water with Na/K ratios of 23:1 and 42:1, respectively, while the feed conversion ratio(1.02±0.01), oxygen consumption, and ammonia-N excretion rate was the lowest in the medium with a Na/K ratio of 23:1. Gill Na +-K +-ATPase activity, as an indicator of osmoregulation, peaked in the treatment where the Na/K ratio was 17:1. The total hemocyte count, respiratory burst, and immune-related enzyme activities(ALP, LSZ, PO, and SOD) of L. vananmei were affected significantly by Na/K ratios( P 0.05). After challenged with Vibrio harveyi, the cumulative mortality of shrimp reared in a Na/K ratio of 23:1(30±14.14)% was significantly lower than the control(75±7.07)%. In conclusion, the addition of K + to low-salinity well water in L. vannamei cultures is feasible. Na/K ratios ranging from 23:1 to 33:1 might improve survival and growth. Immunity and disease resistance are also closely related to the Na/K ratio of the low-salinity well water. The findings may contribute to the development of more efficient K + remediation strategies for L. vananmei culture in low-salinity well water. 相似文献
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Pen a 1 is a major shrimp allergen that induces an allergy. The aim of this study is to assess the effect of simulated gastrointestinal
fluids on the allergenicity of Pen a 1. Purified Pen a 1 from shrimp (Penaeus vannamei) was subjected to digestion in SGF (simulated gastric fluid) and SIF (simulated intestinal fluid) for a set time. The allergenicity
of digestive Pen a 1 was analyzed by immunoblotting and Ci-ELISA, using pool sera from patients with shrimp specific IgE.
The results showed that Pen a 1 exhibited a decrease in allergenicity with increasing digestion time in the SGF and SIF. However,
Pen a l exhibited strong resistance to digestive fluids, and all yielded fragments (33 kD, 23 kD, and 14 kD) showed allergic
activity. Therefore, anti-digestion may be an important factor for Pen a 1 to induce an allergy. 相似文献
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采用双因子交互的方法研究了不同温度和pH值对南美白对虾淀粉酶、蛋白酶和脂肪酶活性的影响。结果表明,南美白对虾肝脏、肠道、胃的淀粉酶最适温度分别为30℃、35℃、30—35℃,最适pH均为6.2。肝脏、肠道、胃的蛋白酶最适温度分别为50—65℃、55—65℃、60℃,肝脏蛋白酶最适pH为8.5—9.0,肠道蛋白酶最适pH为7.5—8.5,胃蛋白酶最适pH为2.0和5.5—6.5。脂肪酶的活力很小,肝脏、肠道、胃的脂肪酶最适温度均为37℃ ,最适pH均为7.7。同时测得南美白对虾肠道、肝脏、胃组织内的pH分别为6.7—7.0、5.9—6.1、5.1—5.3。在三种消化酶各自最适的温度、pH值下,比较其活力大小,在肝脏、肠道、胃均为蛋白酶>淀粉酶>脂肪酶。 相似文献
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描述中国对虾体部肌肉解剖,指出中国对虾体部的肌肉结构与分布和白对虾相似,但两者的肌肉束数目各有不同,详细区别用表格方式列于文中。 相似文献
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为高质化利用南美白对虾加工副产物蛋白资源,本研究以南美白对虾加工副产物虾头虾壳为原料,蛋白水解度为考察指标,采用单因素和响应面试验优化酶解工艺。检测虾蛋白肽分子量的分布范围,评价其抗氧化能力及免疫调节作用。结果表明,碱性蛋白酶与虾头内源酶自溶酶解具有较好的协同作用,最佳酶解工艺参数值为:酶添加量4%、酶解时间6.5 h、酶解温度40℃、料液比1∶5。经蛋白层析仪检测,分子质量分布在75~1 355 Da的蛋白肽占比达到76.35%。虾蛋白肽的羟自由基清除率IC50为4.64 mg/mL、DPPH自由基清除率IC50为3.08 mg/mL,提示其具有一定的抗氧化能力。虾蛋白肽中剂量组(10 mg/kg)能显著促进淋巴细胞增殖,并提高免疫低下模型小鼠的免疫器官指数和吞噬指数,表明虾蛋白肽具有显著的免疫调节作用。 相似文献