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Three isonitrogenous diets containing 60 g kg–1, 90 g kg–1 or 120 g kg–1 lipid were formulated and fed to the Litopenaeus vannamei (2.00 ± 0.08 g) under two salinities (25 or 3 psu) in triplicate for 8 weeks. Shrimp fed 90 g kg–1 lipid had higher weight gain and specific growth rate than shrimp fed the other two diets regardless of salinity, and the hepatosomatic index increased with increasing dietary lipid at both salinities. The shrimp at 3 psu had significantly lower survival and ash content, higher condition factor, weight gain and specific growth rate than the shrimp at 25 psu. Increasing dietary lipid level induced the accumulation of serum MDA regardless of salinity, and at 3 psu, it reduced the serum GOT and GPT activities and the mRNA expression of TNF‐α in intestine and gill of L. vannamei. The hepatopancreatic triacylglycerol lipase (TGL) and CPT‐1 mRNA expression showed the highest value in shrimp fed 90 g kg–1 lipid diet at 3 psu. This study indicates that 120 g kg–1 dietary lipid may negatively affect the growth and induce oxidative damage in shrimp, but can improve immune defence at low salinity; 60 g kg–1 dietary lipid cannot afford the growth and either has no positive impact on the immunology for L. vannamei at 3 psu.  相似文献
2.
An experiment was conducted to replace soya bean meal (SBM) with cashew nut meal (CNM) in the diet of tilapia (Oreochromis mossambicus). Five isonitrogenous (30% CP) and isolipidic (6% CL) diets, CNM0 to CNM4, were prepared replacing SBM at 0%, 12.5%, 25%, 37.5% and 50% with CNM. The feeding trial was conducted in FRP digestibility tanks of 150 L capacity for 60 days. Twenty tilapia fry (20.56 ± 0.05 g) were stocked in each tank. The final weight, weight gain and weight gain% of tilapia that received the CNM4 diet were significantly higher (p < .01) among the treatments. The significantly higher nutrient utilization efficiency in terms of FCR, PER, PRE and LRE was obtained in the CNM4 group. Similarly, a significantly lower (p < .01) body moisture content and a significantly higher (p < .05) body protein content were also observed in the CNM4 diet‐fed group. In tilapia fed the CNM4 diet, the activity of both protease and amylase enzymes was significantly higher (p < .05), but the amylase:protease ratio (A:P) was significantly lower (p < .05). Protease, amylase and A:P were positively correlated with the nutrient digestibility coefficient. The serum protein, albumin and globulin of tilapia fed the CNM4 diet were significantly higher (p < .05) and the liver status enzymes did not vary (p > .05) among the treatments. It can be concluded from the study that 50% replacement of SBM with CNM in the diet is suitable for the enhancement of growth, nutrient utilization and health status of tilapia.  相似文献
3.
为探讨饲料蛋白质水平对匙吻鲟生长、体组成、消化酶活性、血清生化指标、抗氧化性能的影响。配制了5个不同蛋白质水平(35.44%、37.20%、39.19%、42.05%和45.30%)的等脂饲料,将初始体质量为(158.00±0.29) g的匙吻鲟在室外养殖系统中进行56d的饲养。结果显示:①随着饲料蛋白质水平的提高,实验鱼的增重率(WGR)和特定生长率(SGR)呈先上升后下降的趋势,其中39.19%、42.05%组的WGR和SGR显著高于35.44%、45.30%组;45.30%饲料组的蛋白质效率(PER)显著低于其他各组。以WGR和SGR为参考指标,回归分析结果表明,匙吻鲟获得最佳生长时对饲料中蛋白质水平的要求分别为40.67%和40.84%。②随饲料蛋白质水平的提高,实验鱼体成分没有显著性变化。③39.19%组蛋白质表观消化率显著高于其他组,45.30%组脂肪表观消化率和干物质表观消化率显著高于39.19%组和42.05%组;42.05%组肠蛋白酶活性和肝脏脂肪酶活性显著高于其他组;42.05%组肝脏淀粉酶活性略高于其他组;肝脏蛋白酶活性没有明显变化趋势。④饲料蛋白质水平对匙吻鲟血清生化指标有显著影响。39.19%、42.05%组实验鱼的谷丙转氨酶(ALT)显著低于其余各组;37.20%、39.19%组的球蛋白(GLOB)含量显著高于其他组,35.44%组白蛋白(ALB)含量显著低于其他组;总蛋白(TP)含量39.19%、42.05%和45.30%组之间无显著性差异。⑤饲料蛋白质水平为39.19%以上时,血清过氧化氢酶(CAT)活性显著高于低蛋白质水平组;除37.20%组,其余各组间超氧化物歧化酶(SOD)活性差异不显著;丙二醛(MDA)含量各组之间没有显著性差异。研究表明,在本实验条件下,匙吻鲟适宜饲料蛋白质水平为40%~41%。  相似文献
4.
The objective of the study was to evaluate the utilization of biofloc meal as a feed ingredient in enhancing the growth and health status of African catfish (Clarias gariepinus) juvenile. The study consisted of two experiments, that is digestibility and growth experiments. The digestibility of two biofloc meals produced with two different carbon sources, that is tapioca and molasses, were assessed in the digestibility experiment. Whereas the effect of four dietary treatments with different levels of biofloc meal, that is 0%, 5%, 10% and 20%, on the fish growth performance, feed utilization, immuno‐haematological response, antioxidant status and robustness against environmental stress were evaluated in the growth experiment. The results showed that the digestibility of dry matter, protein, lipid and phosphorus of biofloc grown using molasses as the carbon source were remarkably higher than that grown using tapioca (p < 0.05). The inclusion of biofloc meal in the diets at 10% and 20% resulted in higher feed intake, fish growth and final biomass and protein efficiency ratio, and lower feed conversion ratio (p < 0.05). Furthermore, the red blood cells counts, phagocytic, lysozyme activities and antioxidative capacity were significantly enhanced in the fish provided with diet containing 20% biofloc meal (p < 0.05).The fish survival following salinity stress test was higher in the treatments with biofloc meal at 10% and 20% inclusion levels. In conclusion, dietary inclusion of biofloc meal could improve the growth performance and health status of African catfish juvenile and an inclusion level of 20% could be recommended.  相似文献
5.
The aim of the present study was to study the effects of different prebiotics (galacto‐, fructooligosaccharide and inulin) on immune response and oxidative stress of common carp (Cyprinus carpio) fingerlings at the molecular level. A total number of 240 fish (13.85 ± 0.85 g) were supplied and randomly stocked in twelve fiberglass tanks (20 specimens per tank). Fish were fed a basal formulated diet (Control) or basal diet supplemented with equal level (2%) of different prebiotics (four treatments repeated in triplicated) for 8 weeks. At the end of feeding trial, the expression of immune‐related genes (interleukin 1 beta [IL‐1β], IL‐8, IL‐10, lysozyme [LYZ], tumour necrosis factor alpha [TNF‐α] and transforming growth factor beta [TGF‐β]) were determined in head kidney and intestine tissues and the expression of antioxidant‐related genes (glutathione S‐transferase [GST‐α], glutathione reductase [GR] and glutathione peroxidase genes [GPX]) were studied in intestine. The results revealed that dietary administration of prebiotics modulated the expression of immune‐related genes and the degree of expression was affected by the type of prebiotics and the organ that was used for analyses. Also, evaluation of antioxidant genes expression showed that GSTα and GR expression levels increased as a result of feeding common carp with the prebiotics. According to these findings, it can be concluded that feeding on different prebiotics had altered effects on the expression of immune and antioxidant‐related genes.  相似文献
6.
  1. Reefs built by the annelid worm Sabellaria alveolata in the Bay of Mont‐Saint‐Michel (France) are the most extensive intertidal biogenic structures within Europe. Before and after mussel farming extensions, a study designed to provide a biological health index of the Sainte‐Anne reef (223 ha) was carried in 2001 and 2007 to serve as an easy‐to‐use management tool and to ensure endangered reef portions were properly targeted and protected.
  2. Coupled physical and biological parameters were included in a spatial Health Status Index (HI). A spatial and temporal mapping survey of the HI showed a continuous deterioration of the reef's state of health, particularly in its central part. This degradation correlates with the colonization of the Pacific oyster Crassostrea gigas and with increasing silt deposits on the reef.
  3. A combination of several factors is likely to explain such rapid reef deterioration: (1) an increase in trophic competition between cultivated and wild suspension‐feeders that is detrimental to the annelids; (2) a modification in the hydrodynamics and consequently in sedimentary patterns leading to an increase in silt deposition; and most importantly (3) an increase in recreational harvesting of oysters and associated reef trampling, resulting in reef fragmentation.
  4. Understanding the parameters that influence the reef dynamics is necessary in order to help efficient and effective management and policy focusing on the conservation status of large biogenic structures.
Copyright © 2011 John Wiley & Sons, Ltd.  相似文献
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