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171.
We have studied the seasonal relationship between growth and circulating growth hormone (GH), hepatic GH-binding and plasma
insulin-like growth factor-I immunoreactivity in gilthead sea bream,Sparus aurata. The seasonal increase in plasma GH levels preceded by several weeks the summer increase in growth rates. In contrast, a
marked increase in hepatic GH-binding with a high degree of endogenous GH occupancy was found during the period of maximum
growth which suggests an enhanced sensitivity of liver to GH action. Thus, circulating levels of immunoreactive IGF-I, probably
derived from the liver in response to GH action, were positively correlated with growth throughout the experimental period
although a consistent relationship between growth and circulating GH was not found. In spite of this, we consider that, in
gilthead sea bream, as in several other teleosts, the availability of endogenous GH can limit growth. Thus, under environmental
conditions of suboptimal growth, a single intraperitoneal injection of recombinant rainbow trout GH (rtGH) induced over the
dose range tested (0.75, 1.5, 3 μg g BW−1) an increase in plasma IGF-I-like immunoreactivity comparable to that seen during the period of maximum growth. 相似文献
172.
The Potential for Replacement of Live Feeds in Larval Culture 总被引:6,自引:0,他引:6
David A. Jones Mohd. Salleh Kamarudin Lewis Le Vay 《Journal of the World Aquaculture Society》1993,24(2):199-210
173.
Sylvie Dufour Maïté Montero Nadine Le Belle Marc Bassompierre Judy A. King Robert P. Millar Richard E. Peter Yves-Alain Fontaine 《Fish physiology and biochemistry》1993,11(1-6):99-106
Using specific radioimmunoassays for the two GnRH molecular forms present in the European eel, Anguilla anguilla, (mGnRH and cGnRH II), we compared their distributions in the pituitary and different parts of the brain of female silver eels, as well as the modifications of their levels in experimentally matured female eels (treated with carp pituitary extract). In control eels, mGnRH levels were higher than cGnRH II levels in the pituitary, olfactory lobes and telencephalon, di- and mesencephalon, while the opposite was found in the posterior part of the brain (met- and myelencephalon). Experimental sexual maturation of the gonads significantly increased mGnRH levels in the pituitary and anterior parts of the brain; such a positive effect was not observed on the low cGnRH II levels, which were, in contrast, reduced. These data indicate that the positive feedback of gonadal hormones on GnRH, that we previously demonstrated, would specifically affect the mGnRH form. The differential distribution and control of mGnRH and cGnRH II suggest that these two forms have different physiological roles in the eel. The large increase in mGnRH during sexual maturation suggests the prime implication of this form in the neuroendocrine control of reproduction. 相似文献
174.
175.
Vu Ngoc Ut Lewis Le Vay Truong Trong Nghia & Tran Thi Hong Hanh 《Aquaculture Research》2007,38(14):1563-1568
Cannibalism is one of the main causes of mortality in the culture of the mud crab Scylla paramamosain, particularly in the early post‐larval and juvenile stages when the densities of hatchery‐reared crabs may be very high before stocking into ponds or release into the wild for stock enhancement. In a series of experiments investigating cannibalism mitigation, the influence of stocking density, the effectiveness of sand substrate, brick and shell shelters and feed type were compared in culture of crabs from instar 1 for short nursery periods of 15–30 days. Inclusion of brick and shell shelters significantly increased survival over sand substrate alone. However, inclusion of shelters did not affect growth rates. In scaled‐up nursery production in lined‐ponds, with shelters, live Artemia biomass and fresh chopped shrimp or tilapia were found to be equally effective feeds for juvenile crabs stocked at a density of 70 m−2 from instar 1 and grown for 30 days [52–66% survival, 21.6–24.6 mm carapace width (CW)]. In an extended nursery period for a further 30 days, crabs of 22 mm CW, stocked at 30 m−2 in the same ponds, attained a final size of 34.5–36.2 mm CW with a survival of 64.3–67.0% using the same feeds. 相似文献
176.
177.
研究了不同投喂频率(1,2,3,4和5次·d-1)对凡纳滨对虾生长、存活率和水质的影响。试验在室内2m3的圆形水泥池(d=1.6m)中进行,采用全封闭养殖模式,凡纳滨对虾(初始重量为0.24g)养殖密度为50尾·m-3,投喂人工配合饲料(粗蛋白含量为42.98%)。通过7周的试验,结果表明,投喂频率为1~4次·d-1时,随着投喂频率的增加,对虾增重率显著增加;投喂频率由4次·d-1增加到5次·d-1时,对虾增重率略有增加,但差异不显著。凡纳滨对虾的成活率在1次·d-1时最低,2次·d-1时最高,2~5次·d-1时随着投喂频率的增加而降低(投喂频率为1和2次·d-1之间、3和4次·d-1之间差异显著)。投喂频率为3次·d-1时饲料系数最低,蛋白质效率最高。随着投喂频率1~3次·d-1增加,饲料系数逐渐显著降低,蛋白质效率显著递增;而投喂频率从3~5次·d-1增加时,饲料系数增大,蛋白质效率逐渐下降(3和4次·d-1差异显著;4和5次·d-1之间差异不显著)。投喂频率对水环境中的pH值、H2S含量、COD、盐度等水质指标没有显著影响;在养殖后期水环境中投喂频率3~5次·d-1的NH 4和NO-2浓度较投喂频率1~2次·d-1时高。 相似文献
178.
179.
180.
Pierre-Yves Le Bail Geneviève Boulard Bruno Barenton Michel Zygmunt 《Fish physiology and biochemistry》1989,7(1-6):243-251
A method for the purification of chinook Salmon (Oncorhynchus tshawytscha) GH, which retains its biological activity, is described. The biological activity was investigated with an established radioreceptor
assay using liver membranes from pregnant rabbits and bovine GH as standard and labelled hormone. The enrichment of the preparation
was checked with electrophoresis (SDS-PAGE). Extraction and further steps were carried out using low molarity alkaline buffer
(pH 8–10, M = 100 mM). Three chromatography steps were performed (Concanavalin-A sepharose, Bio-gel P60, DEAE). Ion exchange
chromatography was performed under isocratic conditions (using a 50 cm column). Two isoforms (sGH1 and sGH2) were isolated.
The purification yield is 0.7% compared to lyophilized pituitaries. The molecule is homogeneous in SDS-PAGE. Contamination
by prolactin, gonadotrophin and corticotrophin is negligible (< 0.5%). It could be demonstrated that the biological activity
of the preparation is maintained since this preparation stimulates the growth of juvenile trout (Salmo gairdneri) and binds specifically (35%) to trout liver membranes. 相似文献