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采用荧光显微技术,对2006年长江口及近海水域20个站点的表层及10m层或潜水体冬、春两季的浮游病毒丰度进行了检测,对浮游病毒丰度在季节(冬、春两季)、水平分布和垂直分布上的变化进行了探讨.调查区浮游病毒丰度在冬、春季节上并无明显差异,但在水平分布上存在很大差异,河口区浮游病毒直接检测量(Virus Direct Count, VDC)达到10^7个/ml,近海水域VDC为10^6个/ml,河口区的浮游病毒丰度都明显高于近海水域病毒丰度 (P<0.01).在垂直分布上,冬、春两季长江口水域水深小于10m的站位,表层浮游病毒丰度与底层病毒丰度无明显差别,水深大于10m的站位,表层水样的浮游病毒丰度都高于10m水层病毒丰度,说明长江口浮游病毒的垂直分布与站位总水深有关.还通过比较各站点VDC与叶绿素a含量的数据,分析了二者之间的相关性:冬季浮游病毒丰度与叶绿素a含量成正相关性;春季浮游病毒丰度与叶绿素a含量成负相关性,但病毒丰度受叶绿素a含量的影响仅为10%-11%. 相似文献
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不同脂肪水平下添加胆汁酸对大菱鲆(Scophthalmus maximus)幼鱼生长、体组成和脂肪代谢的影响 总被引:2,自引:0,他引:2
在10%和18%两个脂肪水平下,分别添加0%、1.5%的胆汁酸,配制成四种等氮饲料,投喂初始平均体重为(45.78±0.11)g的大菱鲆(Scophthalmus maximus)幼鱼8周,研究两个脂肪水平下添加胆汁酸对大菱鲆幼鱼生长、体组成和脂肪代谢的影响。结果表明:饲料脂肪水平升高或添加胆汁酸均能显著提高大菱鲆幼鱼增重率、特定生长率、蛋白质效率,降低饵料系数(P0.05);相同脂肪水平下,添加胆汁酸显著提高了实验鱼的生长,降低了肝体比(P0.05)。随着饲料脂肪水平的升高,组织中粗脂肪含量呈上升的趋势;而添加胆汁酸降低了组织中脂肪的蓄积,但全鱼与肌肉中水分、粗蛋白含量主要受饲料中胆汁酸水平的影响(P0.05)。胆汁酸能显著降低大菱鲆幼鱼肌肉PUFA含量(P0.05),增加SFA、MUFA含量。饲料添加胆汁酸能降低实验鱼血清甘油三酯、总胆固醇、高密度脂蛋白胆固醇、低密度脂蛋白胆固醇含量及谷草转氨酶、谷丙转氨酶活性(P0.05),但饲料脂肪水平对血液生化指标的影响呈相反趋势。饲料脂肪水平的升高或添加胆汁酸均能提高实验鱼肝脏脂蛋白脂酶、肝脂酶、总脂酶和肠道脂肪酶活性(P0.05),且胆汁酸和脂肪二者之间的交互作用对脂肪代谢有显著影响(P0.05)。综上所述,在2个脂肪水平下添加胆汁酸均能促进大菱鲆幼鱼的生长,提高饲料利用状况,促进脂肪消化吸收,降低组织中粗脂肪含量。 相似文献
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The present trial was conducted with starry fl ounder Platichthys stellatus broodstock to evaluate the effects of dietary vitamin A,ascorbic acid,and α-tocopherol on the gonadal development and reproductive performance.8 000 IU/kg diet vitamin A(VA group),500 mg/kg diet ascorbic acid(Vcpp group),or 250 mg/kg diet α-tocopherol(α-TA group)was added into basal diet to create 3 vitamin experimental diets,respectively.Each diet was fed to 450 starry fl ounder broodstock for 104 days.Samples were collected weekly.The gonadosomatic index(GSI)of 3 vitamin experimental groups fi rst decreased and then increased.Maximum GSI of Vcpp group was higher than that of α-TA group but lower than that of VA group.The spawning periods of 3 vitamin experimental groups lasted 49,56,and 45 days,respectively.No mature eggs were observed in the control group during the trial.The absolute fecundity(AF)and relative fecundity(RF)of α-TA group was higher than that of Vcpp group but lower than that of VA group.The results suggest that different vitamins play different roles in the fi sh reproductive process.Vitamin A stimulated the maturation of the ovary,ascorbic acid prolonged the spawning period,and α-tocopherol affected the development of the eggs. 相似文献
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