共查询到19条相似文献,搜索用时 640 毫秒
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山东天神饲料有限公司自行研制开发的生长素I号绿色添加剂.经过多年的试验、筛选和应用.具有对水产动物促生长效果明显、增强免疫力、对环境无污染等优点。深受养殖户的青睐。丰产鲫2004年引种到山东进行试养,生长速度快,个体大.肉味鲜美.推广前景广阔。但生长素I号对丰产鲫的促生长效果尚不清楚.本试验旨在探讨生长素I号对丰产鲫生长的影响。 相似文献
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合方鲫2号是在国家级水产新品种——合方鲫的基础上,通过多步法育种技术研制的新型优质鲫鱼.2021年,湖南津市农场养殖基地进行了合方鲫2号水花培育试验.在3个月的养殖试验过程中,合方鲫2号平均体重呈现稳步增长态势,4月龄平均规格已达0.12千克/尾,最大个体达0.20千克,充分表现了合方鲫2号生长速度快的特点.养殖试验还... 相似文献
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Anita M. Kelly Christopher C. Kohler E. Gordon Grau 《Journal of the World Aquaculture Society》1996,27(4):384-401
The effects of a mammalian growth hormone-releasing hormone (GHRH), PrebGRF(1–78)OH (bGHRH), on growth and serum growth hormone (GH) levels were investigated in tilapias Oreochromis mossambicus and O. niloticus × O. aureus . Fish were injected intramuscularly or implanted intramuscularly (Silastic or cholesterol implants) with distilled water, 0.1 μg/kg bGHRH, 1.0 μg/kg bGHRH, 10.0 μg/kg bGHRH, or 100.0 μg/kg bGHRH and compared to untreated controls, fish implanted with 60 mg/kg 17α-methyltestosterone (MT), or a combination of bGHRH concentrations plus either MT, 0.01 μg/kg of a thyroid hormone (T3 ), or 0.01 μg/kg of a glucocorticoid (DEX). The bGHRH increased serum GH levels in tilapia maintained at suboptimal temperatures (18 C). Serum GH levels were highest (5.3–0.45 ng/mL) for fish injected with 10.0 μg/kg bGHRH. Fish implanted with a Silastic implant containing 10.0 μg/kg bGHRH had significantly higher (4.35–0.35 ng/mL) serum GH levels than those with an equivalent dosage in a cholesterol implant. The addition of MT, thyroid hormones, and glucocorticoids did not increase serum GH levels above those obtained for fish receiving bGHRH alone. Tilapia reared at suboptimal temperatures and implanted with 10.0 μg/kg and 100.0 μg/kg bGHRH had significantly greater increases in weight and length than control fish. Fish implanted with bGHRH, MT or bGHRH plus MT had significantly higher moisture and protein content, while fat and ash contents were significantly lower than controls or sham-implanted fish. Fish implanted with bGHRH or bGHRH plus MT had significantly higher gonadosomatic indices than fish implanted with MT alone, shams or non-treated controls. This study demonstrates that a mammalian GHRH stimulates release of GH, promotes somatic and gonadal growth and may affect reproductive performance in tilapia. 相似文献
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美国大口胭脂鱼当年苗种生长的初步研究 总被引:2,自引:0,他引:2
美国大口胭脂鱼 [(Ictiobuscyprinellus(Valenci ennes) ],又名巨口牛脂鲤 ,属鲤形目胭脂鱼科 ,原产于北美洲 ,引入我国时间不长。关于它在幼鱼阶段的外部形态特征、某些生理特性及毒性等研究已有一些报道[1- 3] 。笔者对其当年苗种的生长情况进行了观察 ,以期了解在人工饲养条件下 ,该鱼种在苗种阶段的生物学特性 ,为养殖生产提供一些参考。1 方法试验于 1998年 5月至 1998年 11月在湖北农学院实践教学水产基地进行。试验材料鱼购自湖北省水产研究所 ,鱼苗规格 5日龄 ,用尼龙袋充氧运回。1 1 试验方法试… 相似文献
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Growth hormone concentrations in juvenile cocho salmon were determined after intraperitoneal injections (yearlings; age 1+) and oral treatments (yearlings and fry; age 0+) with clonidine. Weights and lengths were also measured in coho juveniles fed diets supplemented with clonidine.
Plasma growth hormone concentration increased significantly (78.2%) 24 h after injection. Yearlings fed clonidine showed a significant increase (136%) in plasma growth hormone after 14 days, and levels remained elevated through 28 days (116%) before dropping to control levels at 42 days. Coho yearlings fed clonidine showed no significant increase in growth compared to controls after 56 days of treatment, but coho fry were significantly heavier (33%) and longer (8%) after 70 days. 相似文献
Plasma growth hormone concentration increased significantly (78.2%) 24 h after injection. Yearlings fed clonidine showed a significant increase (136%) in plasma growth hormone after 14 days, and levels remained elevated through 28 days (116%) before dropping to control levels at 42 days. Coho yearlings fed clonidine showed no significant increase in growth compared to controls after 56 days of treatment, but coho fry were significantly heavier (33%) and longer (8%) after 70 days. 相似文献
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本研究通过逐日测量7~24日龄鳜Siniperca chuatsi仔、稚鱼的全长和体高,及100尾24日龄鳜稚鱼的全长、体长、头长、吻长、体高,及体质量,运用相关分析和通径分析研究这5个形态性状对体质量的影响。结果显示:经过18d的养殖,鳜稚鱼全长增长189.55%,体高增长152.23%;全长、体高与日龄的回归关系分别为TL=0.019D~2+0.181D+4.674,BH=-3.227E-5D~3+0.005D~2+0.077D+1.364。相关分析结果表明:各形态性状与体质量间相关系数均达到极显著水平(P0.01)。多元回归分析发现,仅全长对体质量的影响达到显著性水平,其相关系数P_1=0.965,是影响鳜稚鱼体质量的主要性状。 相似文献
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植物生长调节剂对雨生红球藻细胞增殖及虾青素积累的影响 总被引:1,自引:1,他引:0
研究了4种植物生长调节剂对雨生红球藻细胞增殖、质量(干)、虾青素含量的影响.单因子试验结果表明,4种植物生长调节剂对雨生红球藻的细胞增殖在生长前期作用不明显,在对数生长期有明显的促进作用,质量(干)和虾青素含量有明显的增加;其中α-奈乙酸(NAA)、6-苄基嘌呤(6-BA)、2,4-二氯苯氧乙酸(2,4-D)、赤霉素(GA3)的最佳质量浓度分别为:0.5、0.5、0.1、0.5 me/L.正交多因子试验结果表明:培养雨生红球藻添加6-BA、N从和GA3的最佳质量浓度分别为0.5、0.1、0.05 mg/L. 相似文献
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本实验以美国青蛙为材料,采用定期投喂含基因重组生长激素的饲料,研究外源基因重组生长激素对美国青蛙生长、成活、变态以及肌肉蛋白含量的影响。实验分成三组,每组三平行。每十天投喂实验饲料一次,基因重组生长激素的浓度分别为0.00μg/g体重、0.05μg/g体重和0.50μg/g体重。其中0.00μg/g为对照组,0.05μg/g和0.50μg/g为实验组。结果表明,基因重组生长激素能显著提高美国青蛙的生长以及极显著提高蛙体肌肉中的蛋白质含量(p<0.01),对青蛙的变态和饲料系数无显著影响,但是添加0.50μg/g体重的生长激素能使青蛙的成活率降低。因此,基因重组生长激素适宜的投喂浓度为0.05μg/g体重。 相似文献
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J. Pérez-Sánchez J.A. Calduch-Giner M. Mingarro S. Vega-Rubín de Celis P. Gómez-Requeni A. Saera-Vila A. Astola M.M. Valdivia 《Fish physiology and biochemistry》2002,27(3-4):243-258
Growth hormone (GH), prolactin (PRL) and somatolactin (SL) are single chain proteins structurally and functionally related. Fish PRL and GH receptors (PRLR, GHR) have been characterized in several fish species. There is limited evidence of fish PRLR isoforms, but emerging data support the existence of different GHR variants. In gilthead sea bream, black sea bream, turbot and fugu, but not in zebrafish, GHR has retained an exclusive fish intron (10/10A). In gilthead sea bream and turbot, this intron is not alternatively spliced, but the black sea bream intron is either removed or retained during mRNA processing, resulting in a long GHR isoform with a 31 amino acid insertion that does not alter the open reading frame. This or any other GHR variant are not found in gilthead sea bream, but a truncated anchored form has been reported in turbot. The latter GHR isoform comprises extracellular and trans-membrane domains, the first 28 amino acids of the intracellular domain and 21 divergent amino acids before a stop codon. This GHR variant is the result of alternative splicing, being the 3′ UTR and the divergent sequence identical to the sequence of the 5′ end of the 9/10 intron. The physiological significance of different fish GHR isoforms remains unclear, but emerging data provide suitable evidence for season and nutrition related changes in the somatototropic axis activity. The up-regulation of circulating GH together with the decrease of plasma titres of insulin-like growth factor-I (IGF-I), an altered pattern of serum IGF binding proteins and a reduced expression of hepatic IGF-I and GHRs represent a mechanism conserved through vertebrate evolution. It secures the preferential utilization of mobilized substrates to maintain energy homeostasis rather than tissue growth. Somatolactin also changes as a function of season, ration size, dietary amino acid profile and dietary protein source creating opposite plasma GH and SL profiles. There is now direct evidence for a lipolytic effect of fish SL, acting at the same time as an inhibitory factor of voluntary food intake. Indeed, long-term feeding restriction results in the enlargement of the summer GH peak, whereas the SL rise coincident with shortened day length is delayed in juvenile fish until late autumn. These findings agree with the idea that SL may act as a marker of energy surplus, priming some particular process such as puberty onset. However, it remains unclear whether SL works through specific receptors and/or dimers or heterodimers of GH and PRL receptors. 相似文献