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Long-term separate and combined effects of environmental hypercapnia and hyperoxia in Atlantic salmon (Salmo salar L.) smolts 总被引:2,自引:1,他引:2
Camilla Diesen Hosfeld Annhild Engevik Ted Mollan Torleif Markussen Lunde Rune Waagb Anne Berit Olsen Olav Breck Sigurd Stefansson Sveinung Fivelstad 《Aquaculture (Amsterdam, Netherlands)》2008,280(1-4):146-153
Atlantic salmon (Salmo salar L.) parr (mean start weight 50 g) were reared in freshwater (FW) and exposed to three levels of oxygen saturation measured in effluent water; control group (93% O2, LO2), medium (111% O2, MO2) and high (123% O2, HO2). Further three groups were exposed to similar water oxygen levels in combination with elevated carbon dioxide levels (17–18 mg L– 1 CO2), named LO2–CO2, MO2–CO2 and HO2–CO2, respectively. The experiment was run in duplicate tanks for 42 days, and the fish were subsequently transferred to the same seawater (SW) regime for 45 days for an assessment of post-smolt growth. As a consequence of the CO2 addition, tank pH levels in the FW period were reduced from 6.7 to 5.9 for the hypercapnia groups compared to for the normcapnia groups. Water temperature in FW ranged between 6.4 and 9.0 °C. Citrate was added to the water to complex labile aluminium.In the CO2 groups observed ventilation frequencies were significantly increased compared to the control (p < 0.05). This difference declined towards the end of the FW period, suggesting acclimation to elevated CO2. The degree of oxygenation appeared to contribute to the acclimation as the lowest mean ventilation frequency on day 36 was found in the HO2–CO2 group and the highest in the LO2–CO2 group. Lower plasma chloride and sodium levels were observed in the CO2 groups relative to the respective oxygenation groups during the FW period, while plasma chloride and sodium levels were normalised to equal levels for all groups after 44 days in SW. No significant differences were found among treatments for blood concentrations of red blood cells, haemoglobin, potassium and glucose during the experiment.By termination of the FW period, the HO2 group had significantly higher body weight than all other groups (p < 0.05), with specific growth rate significantly higher than the CO2 groups (p < 0.05). Further, the condition factor was significantly lower in all the CO2 groups at the end of the FW period compared to the control and normcapnia groups (p < 0.05). Although variable among replicates, occurrence of nephrocalcinosis was 10 times higher in the hypercapnia groups than in the control and normcapnia groups. Mortality was negligible (< 2.0%) during the trial, and most of the mortality occurred following SW transfer. 相似文献
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Tadasu URASHIMA Miki KOMODA Sadaki ASAKUMA Yusuke UEMURA Kenji FUKUDA Tadao SAITO Olav T. OFTEDAL 《Animal Science Journal》2008,79(6):699-709
There appears to be strong evidence supporting four major clades of placental mammals: (i) Afrotheria; (ii) Xenarthea; (iii) Euarchontoglires; and (iv) Laurasiathera. This is the first study in which the carbohydrates have been analyzed in the milks of Xenarthea. Our aim was to clarify whether the saccharides of giant anteater milk resemble those of other eutherian species, especially of the Asian elephant, which is one of the Afrotherea. We found that lactose is a dominant saccharide in this milk, as it is in that of most eutherians, and that the milk contains smaller amounts of oligosaccharides, whose structures were determined as Gal(α1‐3)Gal(β1‐4)Glc (isoglobotriose), Neu5Ac(α2‐6)Gal(β1‐4)Glc (6'‐N‐acetylneuraminyllactose), Neu5Gc(α2‐6)Gal(β1‐4)Glc (6'‐N‐glycolylneuraminyllactose), Neu5Ac(α2‐6)Gal(β1‐4)GlcNAc(β1‐3)Gal(β1‐4)Glc (LST c) and Neu5Gc(α2‐6)Gal(β1‐4)GlcNAc(β1‐3)Gal(β1‐4)Glc. This pattern of milk carbohydrates is rather close to that of the milks of other eutherian species. It is notable that the milk contained oligosaccharides with Neu5Gc residues but no oligosaccharides containing α(2‐3) linked Neu5Ac residues such as Neu5Ac(α2‐3)Gal(β1‐4)Glc. 相似文献
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Forest pasturing of free-roaming livestock is a common practice in many parts of the world, but knowledge on how it affects tree regeneration in boreal forests is lacking. We mapped tree density, livestock site use and accumulated damage to young trees of commercial interest(Norway spruce, Picea abies L. Karst.) on 56 clearcuts inside and outside a fenced forest area used for livestock pasturing in Ringsaker, Norway. Inside the fence 56±1.8% of spruce trees were damaged compared to 37±3.4% outside. Proportion of damaged spruce trees was positively related to cattle use of the clearcut, but not so for sheep. On the most intensively used clearcuts, four out of five trees were damaged. The density of deciduous trees was five times lower inside compared to outside of the fence(varying with plant species). While livestock grazing may reduce resource competition in favour of spruce, the current animal density clearly is impeding forest regeneration in the study area. 相似文献
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Mulubrhan Balehegn Lars Olav Eik Yayneshet Tesfay 《Tropical animal health and production》2014,46(5):889-894
Ficus thonningii (FT) is an important multipurpose fodder tree providing economic and ecological benefits across arid and semi-arid areas in Africa. Despite its availability in many Sub-Saharan African countries, there is lack of information on its effect on animal productivity. Twenty-four male weaned highland goats of age 7?±?1.5 months were randomly assigned to four dietary treatments in a completely randomized block design. All animals were fed wheat straw, water, and salt licks ad libitum. The control group (T1) was fed concentrate mixture at 2 % of their body weight, while in T2, T3, and T4, 25, 50, and 75 % of the weight of concentrate (DM basis), respectively, was replaced by sun dried FT leaf meal. FT leaf meal had acceptable levels crude protein (CP), neutral detergent fiber (NDF), and tannins and has resulted in increased body weight in all treatments. Goats fed T3 diet showed significantly higher (P?<?0.05) values in terms of feed intake, body weight gain, some carcass attributes, and local meat quality indicators than the rest of the treatments. An increase in proportion of FT leaf meal beyond 50 %, however, resulted in decreased body weight gain, and other carcass parameters, despite increased feed intake. Therefore, F. thonningii can be used to replace commercial concentrate mixture up to 50 % to improve feed intake and productivity of Ethiopian highland goats. 相似文献
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人们总是关心其食品的质量 ,主要关注点之一就是日常食品的营养成分。根据意大利、波兰、南非、美国和津巴布韦若干实验的结果 ,鸵鸟肉可被认为是一种保健食品 ,因为其营养价值很高 相似文献