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排序方式: 共有167条查询结果,搜索用时 93 毫秒
81.
J.Ø. HANSEN M.H. PENN K.D. SHEARER T. STOREBAKKEN M. ØVERLAND 《Aquaculture Nutrition》2012,18(3):304-312
Antarctic krill (Euphausia superba) and other marine zooplankton may contain high levels of fluoride. The aim of the present experiment was to determine whether dietary fluoride from Antarctic krill at levels similar to the old and the new EU allowable limits in fish feeds (150 and 350 mg kg?1) would induce kidney lesions in freshwater‐reared Atlantic salmon (Salmo salar). In addition to the diets containing krill, two high‐sodium fluoride (NaF) diets (1500 and 3500 mg kg?1) were used to investigate the effect on growth, feed intake, faecal excretion of minerals and accumulation of fluoride in various tissues. No major effects on growth or feed intake were observed. A higher proportion of the ingested fluoride was absorbed in salmon fed with the NaF diets compared with fish fed with krill shell diets. Fluoride accumulated in liver, kidney and especially bone. Faecal excretion of calcium and magnesium was higher for the NaF‐fed fish compared with fish fed with the control and krill shell diets, whereas the levels of these minerals in plasma were unaffected. Dietary fluoride from krill shells did not induce kidney lesions. One‐third of the salmon fed with the highest NaF diet showed signs of crystal formation within the distal tubules and/or collecting ducts in the kidney. 相似文献
82.
We conducted a study to evaluate the effects of holding water temperature on the fecundity and egg quality of photo‐manipulated Atlantic cod broodstock. Adult cod Gadus morhua were distributed among several 25‐m3 tanks. Three separate photoperiods were used for each group to obtain three spawning per year (in May, July and December). While photoperiod was controlled, the temperature was not controlled and followed the ambient seasonal pattern. Due to the uncontrolled seasonal temperature used, each spawning group experienced different temperatures at a particular gonadal developmental stage. Otherwise, all groups were treated the same. Results showed that the May and July spawning groups released significantly more eggs per kg of fish (four and three times more respectively) than the December spawning group. The egg fertilization success and proportion of normal eggs were also higher in the May and July groups. Possible reason for the difference may be that the May and July groups experienced lower temperatures (4–7°C) during oocyte maturation and ovulation than the December group (7–9°C). Our results show the importance of using lower/natural temperatures during oocyte maturation and ovulation to obtain good quality eggs in photo‐manipulated cod broodstock. 相似文献
83.
Patricia I. M. Silva Catarina I. M. Martins Erik Höglund Hans Magnus Gjøen Øyvind Øverli 《Fish physiology and biochemistry》2014,40(5):1547-1557
Consistent individual variation in behaviour and physiology (i.e. animal personality or coping style) has emerged as a central topic in many biological disciplines. Yet, underlying mechanisms of crucial personality traits like feeding behaviour in novel environments remain unclear. Comparative studies, however, reveal a strong degree of evolutionary conservation of neural mechanisms controlling such behaviours throughout the vertebrate lineage. Previous studies have indicated duration of stress-induced anorexia as a consistent individual characteristic in teleost fishes. This study aims to determine to what degree brain 5-hydroxytryptamine (5-HT, serotonin) activity pertains to this aspect of animal personality, as a correlate to feed anticipatory behaviour and recovery of feed intake after transfer to a novel environment. Crucial to the definition of animal personality, a strong degree of individual consistency in different measures of feeding behaviour (feeding latency and feeding score), was demonstrated. Furthermore, low serotonergic activity in the hypothalamus was highly correlated with a personality characterized by high feeding motivation, with feeding motivation represented as an overall measure incorporating several behavioural parameters in a Principle Component Analyses (PCA). This study thus confirms individual variation in brain 5-HT neurotransmission as a correlate to complex behavioural syndromes related to feeding motivation. 相似文献
84.
Saponins and phytosterols in diets for European sea bass (Dicentrarchus labrax) juveniles: effects on growth,intestinal morphology and physiology
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A. Couto T.M. Kortner M. Penn G. Østby A.M. Bakke Å. Krogdahl A. Oliva‐Teles 《Aquaculture Nutrition》2015,21(2):180-193
This study aimed to elucidate the effects of two soy antinutrients, saponins and phytosterols, on growth, intestinal health and function of European sea bass juveniles. Seven fishmeal‐based diets were formulated: a control diet without antinutrients and six experimental diets containing low or high levels of soyasaponins (SapL and SapH, respectively), low or high levels of phytosterols (PhytL and PhytH, respectively) and low or high levels of soyasaponins + phytosterols (SapPhytL and SapPhytH, respectively). A feeding trial was conducted for 59 days after which blood was collected for plasmatic cholesterol quantification and intestinal samples were collected for histology, digestive enzymes activity and gene expression analysis. Histology was also performed at day 15. PhytL resulted in high distal intestine (DI) relative weight and decreased plasma cholesterol, while PhytH caused inflammatory changes in the DI. SapH depressed maltase and alkaline phosphatase activity in DI and the histological evaluation indicated some inflammatory changes. The SapPhytH resulted in decreased maltase activity in the DI and indications of inflammatory changes that were supported by the results on gene expression profiles. The antinutrients tested did not compromise growth, however, caused some gastrointestinal disturbance that may affect fish in the long term. 相似文献
85.
86.
Geir I. Vestøl Carolin Fischer Olav Høibø Audun Øvrum 《Scandinavian Journal of Forest Research》2016,31(8):758-765
This study provides an analysis on the variability of structural timber of Norway spruce (Picea abies) grown in Norway. Density, modulus of elasticity (MOE) and bending strength were measured on 1188 boards from 205 trees, sampled from 14 sites throughout Southern Norway, Eastern Norway and Trøndelag. The area represents the procurement area for the majority of Norwegian sawmills. The variability of the timber properties was analysed in a linear mixed model where the random variance was divided into variance due to site, variance due to trees and within-tree variance. Models describing variance due to site based on site index, altitude and latitude were developed, and combined with data from the Norwegian National Forest Inventory to estimate mean values and variability of the timber properties. The results showed that major parts of the variance due to site are explained by altitude and site index, and for density also by latitude. Major parts of the variance due to site and the variance due to trees in bending strength and MOE were explained by density. 相似文献
87.
Utilization of H2SO4‐hydrolysed phosphorus from herring bone by‐products in feed for Atlantic salmon (Salmo salar) 0+ postsmolt
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S. Albrektsen E.‐J. Lock G. Bæverfjord M. Pedersen A. Krasnov H. Takle E. Veiseth‐Kent R. Ørnsrud R. Waagbø E. Ytteborg 《Aquaculture Nutrition》2018,24(1):348-365
The utilization efficiency of phosphorus (P) hydrolysed from herring by‐products in feed for Atlantic salmon 0+ postsmolt was studied. Seven diets were produced with a low P level (D1): 5 g soluble P/kg, with P hydrolysed from herring by‐products (D2, D3, D4): 7, 9 and 11 g soluble P/kg, or blue whiting fish bone meal (D5): 9 g soluble P/kg, and with P from NaH2PO4 (D6, D7): 9 g soluble P/kg diet. Diet D7 was also added (NH4)2SO4. Fish fed D1 had significantly lower growth compared to D3, D5 and D7, morphological changes in bone consistent with low mineral contents, significantly reduced scale macromineral contents and changes in P markers, that is bone ALP and NaPi in pyloric caeca. The average P retention was 3.6 and 3.2 g P/kg weight gain, respectively, in D2–D7 and in D1. Fish fed D3, D5 and D6 showed similar growth, P digestibility, tissue mineralization, P retention and P excretion. The dietary P requirement in salmon was met between 5.1 and 7.4 g/kg soluble P (DM). This study shows that P hydrolysed from fish bones can be recycled and used as an efficient P source in feed for Atlantic salmon. 相似文献
88.
E. M. Kolstoe T. Iversen Ø. Østensvik A. Abdelghani I. Secic T. Nesbakken 《Zoonoses and public health》2015,62(2):125-130
As Specific Pathogen‐Free (SPF) pig herds are designed and managed to prevent specific pig diseases, it might be feasible to expand the list of micro‐organisms also including zoonotic pathogens such as Campylobacter coli as this agent has its origin in pigs. In a previous survey, 15 of 16 of SPF herds were found free from human pathogenic Yersinia enterocolitica. Accordingly, three nucleus and seven multiplying herds were surveyed for Campylobacter to investigate whether the Norwegian SPF pig pyramid also might be free from this agent. In conclusion, the intervention of Campylobacter at the herd level might be possible as four of 10 SPF herds tested negative in two sets of samples from both autumn 2008 and summer/early autumn 2010. The four negative herds were all located in remote areas several kilometres away from conventional pig farming while the positive SPF farms were all situated in neighbourhoods with conventional pig production. It seems more difficult to control Campylobacter than some specific animal disease agents and another significant zoonotic agent, Y. enterocolitica, in pig herds. 相似文献
89.
The effect of dietary chitin on growth and nutrient digestibility in farmed Atlantic cod,Atlantic salmon and Atlantic halibut
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The effect of adding 0%, 1%, 2% and 5% chitin from prawn shells in the diets for Atlantic cod, Atlantic halibut and Atlantic salmon on growth was investigated. Nutrient digestibility and feed utilization was investigated in salmon and cod. Atlantic cod grew from 186 ± 29 to 383 ± 78 g (N = 960) over 13 weeks. Dietary chitin had no effect on length, weight, condition, liver size or specific growth rate (SGR). The apparent digestibility (ADC) for protein ranged from 84.7% to 86.5%, lipid between 88.8% and 93.1% and dry matter from 96.1% to 96.6%. Feed utilization varied between 1.08 and 1.11 and was not correlated with dietary chitin content. Atlantic salmon tripled their weight from 199 ± 9 to 615 ± 75 g (N = 480) during the 13 weeks. High inclusions of chitin (>1%) reduced both growth rate and condition. Protein and lipid ADC was negatively correlated with dietary chitin. Feed utilization ranged between 0.86 and 0.90 and was not significantly affected by dietary chitin. Faecal protein increased significantly with increasing dietary chitin, while faecal dry matter and lipid did not. Individually tagged Atlantic halibut grew from 1300 ± 470 to 2061 ± 714 g (N = 70) during 6 months. Individual growth rates varied within each group from being slightly negative to 0.81%·day?1. Diet had no significant effect on growth rates. Atlantic cod and Atlantic halibut seems unaffected by up to 5% chitin additions in the diet, while chitin >1% of diet negatively affects growth and nutrient utilization in Atlantic salmon. 相似文献
90.
M.B. LØFSTEDT 《Aquaculture Nutrition》2010,16(6):625-636
Winter mortality in hatchery reared oyster spat (Ostrea edulis) that received three different diets during the summer period was investigated. Oysters fed a natural type diet had a winter mortality of 18.3 ± 6.3% while oysters fed cultivated algae (a mixture of Tetraselmis suecica, Isochrysis galbana and Chaetoceros muelleri) had a mortality of 73.0 ± 9.7%. A group of oysters fed a mix between the two diets had a mortality of 54.7 ± 10.6%. Tissue samples were taken at the start of the experiment, after the summer period and after the winter period in order to determine growth and the content of glycogen and fatty acids. The glycogen content decreased for all groups during the winter but the decrease was highest in oysters fed the natural diet. This group also contained the largest variety of fatty acids, but there was no difference in the content of the essential fatty acids EPA, DPA and DHA between the groups. It is concluded that transplantation of spat to the sea in spring and early summer may reduce winter mortality since the feeding period on a more varied natural algal diet is prolonged compared to transplantation of spat later in the season. 相似文献