全文获取类型
| 收费全文 | 79篇 |
| 免费 | 7篇 |
| 国内免费 | 16篇 |
专业分类
| 农学 | 1篇 |
| 综合类 | 15篇 |
| 水产渔业 | 85篇 |
| 畜牧兽医 | 1篇 |
出版年
| 2023年 | 3篇 |
| 2022年 | 6篇 |
| 2021年 | 3篇 |
| 2020年 | 2篇 |
| 2019年 | 6篇 |
| 2017年 | 1篇 |
| 2016年 | 2篇 |
| 2014年 | 2篇 |
| 2013年 | 11篇 |
| 2012年 | 8篇 |
| 2011年 | 2篇 |
| 2010年 | 6篇 |
| 2009年 | 4篇 |
| 2008年 | 1篇 |
| 2007年 | 4篇 |
| 2006年 | 3篇 |
| 2005年 | 6篇 |
| 2004年 | 8篇 |
| 2003年 | 5篇 |
| 2002年 | 6篇 |
| 2001年 | 1篇 |
| 2000年 | 1篇 |
| 1999年 | 2篇 |
| 1998年 | 5篇 |
| 1996年 | 3篇 |
| 1995年 | 1篇 |
排序方式： 共有102条查询结果，搜索用时 31 毫秒
1.
亚硝酸盐对越冬红螯螯虾生理指标及肠道菌群的影响 总被引：1，自引：1，他引：0
以越冬红螯螯虾为对象,探讨其在不同亚硝酸盐浓度下的生理指标及肠道菌群变化情况。采用常规生物急性毒性试验法,得到亚硝酸盐胁迫下红螯螯虾的96 h半致死浓度为22.0 mg/L,安全浓度为2.2 mg/L。设置4个实验组,分别为A组(0 mg/L)、B组(0.5 mg/L)、C组(2.3 mg/L)和D组(5.0 mg/L),胁迫6周后取样检测。结果表明:各组成活率、肥满度、肝体指数无显著性差异(P>0.05),但D组成活率、体质量增加率、体长增加率最低。随亚硝酸盐浓度的增加,肝小管排列趋于混乱且大小出现差异,肝小管间结缔组织随之减少,产生空泡化,在D组中变化尤为明显。SOD活性随亚硝酸盐浓度升高而降低,在肝胰腺中,A组显著高于其他3组(P<0.05),D组显著低于其他3组(P<0.05);在肌肉中,A组显著高于C、D组(P<0.05),D组显著低于A、B组(P<0.05)。MDA活性随亚硝酸盐浓度升高而升高,在肝胰腺中,4组均无显著差异(P>0.05);在肌肉中,A组显著低于C、D组(P<0.05)。免疫相关指标均随亚硝酸盐浓度升高而降低,在肝胰腺中,4组ACP、AKP活性均存在显著性差异(P<0.05),A组最高,D组最低;在肌肉中,A组ACP活性显著高于其他3组(P<0.05);4组AKP活性均存在显著性差异(P<0.05),A组最高,D组最低;各组UL活性无显著性差异(P>0.05)。能量代谢指标TG活性随亚硝酸盐浓度升高而降低,A组显著高于D组(P<0.05)。亚硝酸盐胁迫在一定程度上提高了肠杆菌科(Enterobacteriaceae)的比例,且菌群多样性D组最低,A组最高,亚硝酸盐导致了肠道菌群多样性的下降。 相似文献
2.
为探究长期盐度胁迫条件下红螯光壳螯虾肠道基因表达和代谢通路的变化。实验采用Illumina Hiseq 2 500平台对0、5、10和15这4个盐度下养殖5周的红螯光壳螯虾的肠道组织进行了高通量测序。研究共获76 534个unigenes,通过与NR、NT、KO、Swissprot、PFAM、GO和KOG数据库进行比对,成功注释37 378个unigenes。通过引入FPKM(Fragments Per Kilo bases per Million fragments)来估算基因表达水平,基于NR和Pfam两个数据库的蛋白注释结果,448 362个unigenes在GO数据库得到注释。根据KO功能注释与Pathway的联系,9 483个unigenes在KEGG数据库被注释分类到34条通路途径。通过DEGseq进行基因表达差异分析,以盐度0为对照组,显著差异基因筛选条件设置为Q value<0.05且差异倍数|Fold Change|>2,盐度5、10和15组分别获得差异基因2 733、91和236个,其中盐度5组共有2 068个基因显著上调,665个基因显著下调。将所有差... 相似文献
3.
从濒死的红螯螯虾(Cheraxquadricarinatus)的肝胰脏中分离得到可疑病菌L1和L2,经细菌学鉴定2株细菌均为弗氏柠檬酸杆菌(Citrobacterfreundii);经人工感染试验证实L1和L2均导致健康虾发病死亡,其LD50分别为2 2×105CFU/ind、7×105CFU/ind;2株细菌对14种药物的敏感性相似,对9种抗生素敏感,对5种抗生素有抗性。从中筛选出有效药物,应用于生产中取得了较好效果。 相似文献
4.
红螯螯虾的室内人工育苗 总被引：7，自引：1，他引：7
于1996-1998年,在浙北地区,对澳大利亚引进的红螯螯是进行亲虾培育、人工越冬,怀卵孵化,室内人工育苗技术的研究。研究表明,在浙北地区,2.8-4.9g的幼虾经5个月左右的饲养可以达到性成熟并部分怀卵,利用电厂余热水水泥池人工越冬的成活率可达70%以上。越冬后亲是在水温20℃以上即开始交配怀卵,怀卵盛期4-6月。红螯螯虾一年可产卵4次,但只有第一、二次怀卵可用于育苗生产,个体一次怀卵量较少,一般为400-500粒,但群体怀卵比率较高。试验还表明,红螯螯虾出膜幼体即呈幼虾状,需依附母体7-10d后才营独立生活并开口摄食外源性饵料,所研制的幼虾Ⅰ号饲料为红螯螯虾室内人工育苗较好的开口饲料。室内人工育苗成活率可达60%以上。 相似文献
5.
A trial was conducted in 12 purpose-built, commercial, drainable, earthen ponds to evaluate the effect of fish and plant protein and lipid source on the growth, condition indices, and body composition of marron (Cherax tenuimanus). Juvenile marron (1.3±0.28 S.E. g) at the stocking densities of three per square meter were fed for a period of 1 year with four different formulated isoenergetic practical diets (D1, D2, D3, and D4). Three of the test diets (D1, D2, and D3) were isonitrogenous whereas the fourth test diet (D4) was protein-free. Protein and lipid sources in D1 were from Lupin (Lupinus albus) whereas protein and lipid sources in D2 and D3 were from fish meal. Fish oil (3.5%) was added to D1, D3, and D4 whereas sunflower oil was added to D2 and D4 in order to make them isoenergetic. The four test diets were randomly allocated to three replicate ponds.
The lack of protein in D4 did not significantly influence (P>0.05) the mean final weight and specific growth rate of marron. Survival was low in all ponds (13.82–34.66%) but feeding with D4 resulted in a significantly (P<0.05) higher survival than marron fed with D1 and D2. Feeding a diet containing a combination of fish protein and fish oil (D3) resulted in significantly higher (P<0.05) wet tail muscles-to-body weight ratio than was observed with other diets. Tail muscles protein level of all marron was significantly lower (P<0.05) at the end of the trial than at the beginning. EPA and DHA in hepatopancreas and tail muscles of marron were affected by the four test diets. The inclusion of plant protein in formulated diets had a negative impact on the pond environment due to significantly higher unionised ammonia levels that resulted in lower survival. Juvenile marron fed with a plant protein diet had significantly lower protein levels in their hepatopancreas compared to those fed with diets containing animal protein. Feeding marron with lupin protein source (D1) and plant oil (D2) for 1 year did not alter the lipid content of their hepatopancreas. Four test diets had no influence on the fat content of marron hepatopancreas; however, these test diets significantly reduced the protein content of the tail muscles of marron.
Environmental variables, particularly temperature, nitrogen metabolites, and the natural productivity of the ecosystem, greatly influenced the nutritional requirements of the juvenile marron under culture. 相似文献
6.
Ninety sexually mature Cherax quadricarinatus females were exposed to various combinations of photoperiod and temperature for 2 months during the summer. Females were randomly assigned to either “winter” “semi-winter” or “summer” simulation treatments. In the “winter” treatment, crayfish were exposed to a simulated winter photoperiod (gradual decrease from 14L:10D to 10L:14D, 4 weeks at short day length followed by gradual increase to 14L:10D) and temperature (gradual decrease from 27 to 15 °C, held for 4 weeks, and then gradual increase to 27 °C). In the “semi-winter” treatment, crayfish were exposed to a simulated winter photoperiod and a summer temperature (27–29 °C). In the “summer” treatment, the crayfish were exposed to summer water temperatures and a photoperiod of 14L:10D. Following the 2 months of conditioning, the females were stocked for 7 months in small groups with males under environmental conditions similar to those of the “summer” treatment. All females were individually tagged and molting and spawning events were monitored. Females exposed to “semi-winter” conditioning in the summer, demonstrated a threefold increase in the rate of first spawning during the winter (December–February) compared with the other females. Crayfish breeders can easily implement these findings since shifting the breeding season into the winter only requires shortening of the photoperiod in the summer. The stocking of ponds in the spring with large nursed juveniles that hatched from eggs spawned in the winter, would allow the attainment of market size at the end of the limited growout season in temperate zones. 相似文献
7.
The effect of dietary protein source on growth and carcass composition in juvenile Australian freshwater crayfish 总被引：1，自引：0，他引：1
A feed trial was conducted for 12 weeks on juvenile Australian freshwater crayfish (Cherax destructor) (mean weight (SE) 0.82 (0.02)g) maintained on five isoenergetic diets with a protein content of 30%. Diets differed in the primary source of protein used, with meat, snail, soybean, yabby, and zooplankton meals comprising the major protein ingredient, varying from 56–60% of total protein. Mean percentage weight gain per day ranged from 7.57% (yabby meal diet), to 9.42% (snail meal diet). No significant difference occurred in mean weight, percentage weight gain, specific growth rate (%), or survival among diets. A maximum size of 16.44g was attained on the yabby meal diet. Largest mean weight was 8.27g on the snail-based diet. Food conversion ratios were all good, with a minimum value of 0.95 recorded for the snail-based diet. Initial food consumption per day was approximately 5% of mean animal weight, decreasing to around 2.4%, and is collectively described by a power curve. Protein retention ranged from 29.57% in the zooplankton meal diet to 41.15% in the snail-based diet. Carcass composition was influenced by feed type, with the most marked difference occurring in carapace colour. Animals fed the zooplankton-based pellets developed the strongest pigmentation. Recommendations are made for including certain protein-based ingredients in manufactured yabby diets. 相似文献
8.
Cherax albidus (A) and Cherax destructor (D) male juveniles (mean weight 0.95 ± 0.03 g) were reared for 20 weeks on isoenergetic diets containing 150 g kg?1 protein (A 15, D15) or 300 g kg?1 protein (A30, D30). Mean weight, percentage weight gain, and specific growth rate (%) were substantially higher for both species on the 300 g kg?1 protein diet. Mean percentage weight gain ranged from 2.39% day?1 (D15) to 17.59% day?1 (A30). A maximum weight of 33.81 g was attained by C. albidus on the higher protein diet. The most effective utilization of food was observed in C. albidus when fed the higher protein diet (food conversion ratio, 0.79; protein efficiency ratio, 4.21; apparent net protein utilization, 44.64%). Carcass composition was influenced by feed type. The higher protein diet resulted in an increase in carcass protein and ash and a decrease in carcass lipid and energy relative to the low-protein diet (150 g kg?1 protein diet –C. albidus: 37.15% protein, 15.00% lipid, 25.20% ash, 15.55kJ g?1 energy; C. destructor: 38.10% protein, 15.43% lipid, 25.70% ash, 15.65kJ g?1 energy; 300 g kg?1 protein diet –C. albidus: 46.10% protein, 8.71% lipid, 27.36% ash, 14.94kJ g?1 energy; C. destructor: 42.99% protein, 8.56% lipid, 26.44% ash, 14.71kJ g?1 energy). Carcass moisture and calcium were not affected by feed type. The time spent in the intermoult phase of growth was highly dependent on the premoult weight and varied according to diet and to species. A comparison of animals of similar weight (< 8 g) revealed that elevated dietary protein caused a reduction in the intermoult period by 11 days in C. albidus and 7 days in C. destructor. The moult increment, however, was independent of animal weight, and the highest percentage weight increment occurred for C. albidus fed the 300 g kg?1 protein diet (per cent weight increase; A15, 33.1%; A30, 61.3%; D15, 31.2%; D30, 56.5%). Dietary induced morphological changes were also recorded. Animals of a standard carapace length had significantly larger abdomens (both species) and larger claws (C. albidus) when fed the higher protein diet. 相似文献
9.
10.
Rivka Manor Ran Segev Marcia Pimenta Leibovitz Eliahu D. Aflalo Amir Sagi 《Aquacultural Engineering》2002,26(4):263-276
In the process of exploring ways to intensify crayfish culture, a growout system of individual cages (cells) was designed to determine the effects of gender and cell size on the growth of the red claw crayfish Cherax quadricarinatus. Cells of three different diameters—large (25 cm), medium (20 cm) and small (16 cm)—were used. When crayfish were stocked at a mean weight of approximately 10 g, growth rate of males was significantly higher than that of females. The growth rate of the males in the large cells was 0.31±0.14 g/day, while that of the females was 0.18±0.09 g/day. The size of the cell had significant influence on the weight of males. Male crayfish in the large and medium cells grew better than those in the small cells. When males were stocked at a higher mean weight (about 23 g), their mean weight after 206 days was higher in the large cells (69.28±15.72 g) than in the small cells (58.11±12.66 g), suggesting that the growth of large males was also affected by cell size. Regardless of cell size, male animals of this species grew faster than females under conditions of individual cells. This intensive culture method appears to present a powerful improvement in yields, by as much as two orders of magnitude, in comparison with communal cultures. 相似文献