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饮用加银水对模拟失重大鼠肠道微生态及骨钙代谢的影响 总被引:2,自引:0,他引:2
目的 :研究饮用加银水对模拟失重大鼠肠道微生态及骨钙代谢的影响。方法 :30只 SD雄性大鼠随机分为地面对照组 ( GC)、模拟失重对照组 ( SC)和模拟失重饮用 0 .2 0 mg/ L 加银水组 ( SS) ,实验期 2 1d。第 7、14和 2 1天用选择性培养基分别对肠球菌、肠杆菌、双歧杆菌、乳杆菌及类杆菌定量测定 ,并测定饲料钙表观吸收率 ;第 2 1天取右侧股骨测骨密度和骨钙含量。结果 :骨密度和骨钙含量 SC组显著低于 GC组 ,SS组也低于 SC组 ;SC组和 GC组比较 ,SC组出现厌氧菌群的减少和需氧菌群的增加及饲料钙表观吸收率的下降 ,且这种变化出现较早 ,SS组和 SC组比较 ,SS组出现以厌氧菌群中 G 菌的减少和需氧菌群G-菌的增加为主的菌群失调及饲料钙表观吸收率的下降 ,且这种变化出现较晚。结论 :饮用 0 .2 0 mg/ L 加银水可以加重模拟失重大鼠肠道微生态的失调和骨钙代谢的紊乱 ,但需要较长的作用时间 ,且其微生态的失调以 G 细菌减少为主的厌氧菌群减少型 相似文献
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Han YS Liao IC Tzeng WN Huang YS Yu JY 《Comparative biochemistry and physiology. Part B, Biochemistry & molecular biology》2003,136(4):913-920
To understand the changes of serum levels of sex steroids in the wild Japanese eel Anguilla japonica during silvering process, eels collected from the Kaoping River of Taiwan from August 2000 through June 2001 were examined. The maturational stages of female eels before and during silvering were divided into four stages: juvenile, sub-adult, pre-silver and silver stages based on skin coloration and oocyte diameter. Male eels were investigated only in the silver stage. Radioimmunoassays were employed to measure serum levels of estradiol-17β (E2) and testosterone (T). The mean liver mass of the female eels increased significantly during silvering, but the mean hepatosomatic index remained constant. In contrast, mean ovarian mass and gonadosomatic index increased significantly during silvering. Serum concentrations of E2 in females increased significantly during silvering (P<0.05), while E2 was undetectable in silver males. The mean serum T concentrations increased significantly in females (P<0.05) during silvering, with lowest mean values in the juvenile stage and highest mean value in the silver stage. The mean serum T level in the silver males was significantly lower than in silver females (P<0.05). In conclusion, both serum E2 and T concentrations increased with ovarian development of wild Japanese eels during silvering, while serum E2 was undetectable in the silver male eels. The findings support the idea that androgen, but not estrogen, plays a major role in silvering process of the eels in both sexes. 相似文献
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Akihiro Okamura Yoshiaki Yamada Kazuki Yokouchi Noriyuki Horie Naomi Mikawa Tomoko Utoh Satoru Tanaka Katsumi Tsukamoto 《Environmental Biology of Fishes》2007,80(1):77-89
To establish a simple and reliable index for determining silvering stages of the Japanese eel, Anguilla japonica, we observed the colorations of various body parts and biological characteristics of the eels collected in a coastal area
of Japan (Mikawa Bay). The four silvering stages are characterized by the colorations of pectoral fins and ventral skin as
follows: (1) Y1, yellow eel without a metallic hue at the base of pectoral fins, (2) Y2, late yellow eel with a metallic hue
at the base of the pectoral fins but without melanization at the tip of pectoral fins, (3) S1, silver eel with complete melanization
at the tip of pectoral fins but without full pigmented belly in black or dark brown, and (4) S2, late silver eel with black
or dark brown belly. The body size, eye diameter and sexual maturity of each stage increased in the order of Y1, Y2, S1 and
S2 stages, whereas the digestive tract degenerated in the same order, suggesting a sequential development of these ontogenetic
stages identified in the study. The Y1, Y2 and S1 stages could be also distinguished by canonical discriminant function analysis
using three internal (gonad-somatic index, GSI; hepato-somatic index, HIS; and gut index) and two morphometric (condition
factor and eye index) parameters, supporting the significance of these stages. This method of staging for the silvering process
of the Japanese eel appeared to be applicable to all specimens of this species, since this index used only simple external
characteristics that would be easy to observe during field surveys. 相似文献
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