Compensatory growth in Atlantic halibut: Effect of starvation and subsequent feeding on growth, maturation, feed utilization and flesh quality     

Atle Foss  Albert K. Imsland  Erik Vikingstad  Sigurd O. Stefansson  Birgitta Norberg  Skjalg Pedersen  Trond Sandvik  Bjrn Roth 《Aquaculture (Amsterdam, Netherlands)》2009,290(3-4):304-310

A group of juvenile Atlantic halibut (mean, SD, 199.5 g, 44.7) was split into two experimental groups: one group was fed in excess twice a day and later five days a week (i.e. Control group), and the other group was starved for 5 weeks and then subsequently re-fed for 10 weeks (i.e. 5/10 starvation/re-fed group). This treatment was repeated for three years until the fish were harvested (mean final weight, 4.4 kg). A size +specific compensatory response was seen; partial compensation was observed in halibut weighing less than 500 g whereas full recovery growth was seen in halibut over 2 kg. Food consumption and feed conversion efficiency was measured during two full 5/10 starvation/re-fed cycles. The Control group consumed 86% more food in the measurement period, whereas the FCE 40% higher in the 5/10 starvation/re-fed group (FCE = 0.95) compared to the Control group (FCE = 0.68). In males lower gonadosomatic index (2.2 vs. 3.0) and plasma 11-ketotestosterone (0.22 vs. 1.26 ng ml^− 1) levels in the 5/10 starvation/re-fed group were observed during late winter and spring of 2006 (age 3 years) indicating higher age at 1st maturity. Starvation had a significant effect for improving the quality as starved fish had higher muscle pH (6.4 vs. 6.2), less gaping (0.1 vs. 0.3) and harder texture (61.4 vs. 57.6 N). Overall, the rearing on a repeated 5/10 starvation/re-fed regime for 3 years led to full growth compensation, higher feed conversion efficiency, lower male maturation and improved flesh quality.  相似文献   

Long-term effect of photoperiod manipulation on growth, maturation and flesh quality in Atlantic halibut     

Albert K Imsland  Bjørn Roth  Atle Foss  Erik Vikingstad  Sigurd O Stefansson  Skjalg Pedersen  Trond Sandvik  & Birgitta Norberg 《Aquaculture Research》2009,40(11):1260-1269

The aim of this study was to investigate the effect of continuous light at different stages during the production cycle of Atlantic halibut Hippoglossus hippoglossus L. on growth, age at first maturity, endocrine parameters and flesh quality. A group of juvenile halibut [mean (SD), initial weight 191.3 g (44.7)] was reared in indoor tanks under ambient temperature conditions for 38 months until harvesting (mean final weight, 4.6 kg). The entire photoperiod experiment was divided into four phases, where the fish in each phase were exposed to either natural photoperiod (62°33'N) or continuous light (L). Thus, the following five photoperiod combinations were tested: (a) Control group (NNNN), (b) Group 2A (NLNN), (c) Group 2B (NNLN), (d) Group 2C (NNNL) and (e) Production group (LNNN). Exposure to continuous light stimulated growth, and the final mean weights of Groups 2A and 2B were 23% and 11% higher than those of the Control group (NNNN). The final plasma 11-ketotestosteron levels were lower in Groups 2A (2.94 ng mL⁻¹) and 2B (2.46 ng mL⁻¹) compared with the Control (5.29 ng mL⁻¹), Group 2C (5.09 ng mL⁻¹) and the Production group (4.78 ng mL⁻¹) during spring 2007 (age 4 years), indicating higher age at first maturity in Groups 2A and 2B. Photoperiod regime had only a minor, and transient, effect on flesh-quality traits of the fish, whereas a significant seasonal effect was seen with a tendency towards increased gaping, lower pH, lower hardness and lower shear force in July compared with December and March.  相似文献   

Earthworm channels in cultivated clayey and loamy Norwegian soils     

Tore E. Sveistrup  Trond Knapp Haraldsen  Freddy Engelstad 《Soil & Tillage Research》1997,43(3-4)

Studies of earthworm species and their activity, expressed as channels, on cultivated loamy (Humic Cryaquept) and clayey soils (Typic Endoaqualf and Typic Cryaquept) were conducted in southern and central Norway before conversion from conventional to organic cropping systems. At all the three study areas: Landvik (Grimstad), Voll (Ås) and Kvithamar (Stjørdal), the earthworm species Aporrectodea caliginosa, Aporrectodea rosea, Allolobophora chlorotica and Lumbricus rubellus were found. At Landvik, where the deep-burrowing species Aporrectodea longa, A. caliginosa and Lumbricus terrestris dominated, medium (4–6 mm) and coarse (>6 mm) earthworm channels were most numerous below the plough layer. Almost no coarse pores were found at Voll and Kvithamar. The volume of earthworm channels below the plough layer was 0.6–0.8% of total soil volume at Landvik and Voll and 0.3–0.4% at Kvithamar. Earthworm channels >6 mm below the plough layer were useful to identify present and previous activity of deep-burrowing earthworms such as L. terrestris. Below the plough layer, roots were almost entirely restricted to earthworm channels and interaggregate spaces.  相似文献   

Absorption from water as an alternative method for the administration of sulphonamides to rainbow trout, salmo gairdneri. The significance of the pKa value of the sulphonamides and the pH and salt content of the water.     

Torill Bergsj  Trond Helle Bergsj 《Acta veterinaria Scandinavica》1978,19(1):102-109

The effect of variations in pH and salt concentration on the absorption by rainbow trout of sulphonamides from water was investigated. Two trials were carried out: 1) Absorption from fresh water of sulphanilamide (pKa 10.4) and sulphadimidine (pKa 7.4) at pH 4, 6, 8 and 10 over a period of 96 hrs., and 2) Absorption from fresh water and sea water (salinity approx. 31 ‰) of the same two sulphonamides at pH 6 and 8 over a period of 24 hrs. The degree of acetylation of the two sulphonamides in rainbow trout was investigated.  相似文献   

Mixtures of crushed rock, forest soils, and sewage sludge used as soils for grassed green areas     

Trond Knapp Haraldsen  Per Anker Pedersen 《Urban Forestry & Urban Greening》2003,2(1):1

In two container experiments, we evaluated mixtures of crushed rock, forest soil, and sewage sludge for use as growth media in green areas. We applied two types of crushed rock (0–2 mm fraction), two forest soils (sandy loam), and limed sewage sludge (pH 10), and studied the growth of ryegrass (Lolium multiflorum var. westervoldicum) during one growing season.Including ≥0.2 m³ m⁻³ sewage sludge in the soil mixtures initially inhibited growth, presumably due to toxic levels of ammonium-N. Up to 0.25 m³ m⁻³ sludge increased the total yield of ryegrass, but at a level as low as 0.1 m³ m⁻³, more nutrients were available than could be taken up by the crop. At present, up to 0.3 m³ m⁻³ sewage sludge is allowed in soil mixtures used in green areas in Norway, although that level should probably be lowered due to the risk of abnormal (enhanced or inhibited) plant growth, and leaching of nutrients. We recommend a maximum of 0.1 m³ m⁻³ when applying the kind of sludge used in our experiments.All mixtures containing acid forest soil gave better results than those comprising slightly alkaline forest soil. The best mixture for ryegrass was crushed rock and acid forest soil at a ratio of 1:2. Compared to pure acid forest soil ryegrass grew equally well or better on mixtures containing ≥0.50 m³ m⁻³ acid forest soil. The differences in growth between the various soil mixtures were due to texture and physical properties, and to dissimilarities in the effects of sewage sludge on mineralisation of nitrogen in the mixtures comprising acid and slightly alkaline forest soil.  相似文献   

Impact of milking characteristics and morphology of udder and teats on clinical mastitis in first- and second-lactation Norwegian cattle   总被引：1，自引：0，他引：1  

Trond Slettbakk  Asbjrn Jrstad  Thomas B. Farver  John C. Holmes 《Preventive veterinary medicine》1995,24(4):235-244

Data from the Norwegian progeny testing program were used to examine the impact of milking characteristics and morphology of udder and teats on clinical mastitis in first- and second-lactation Norwegian cattle. The study was designed as a 1-1 matched case-control study with herd, parity, days in lactation and calving season as matching variables. Conditional maximum likelihood logistic regression was used to evaluate the effects of three primary (2 min milk, milk leakage and teat-end-to-floor distance) and six other study variables. Treatment records from the Norwegian health card system on acute and chronic clinical mastitis were used to define cases. The chosen model included 565 matched pairs. Significant risk factors of clinical mastitis were decreasing teat-end-to-floor distance (P = 0.02) and periparturient udder edema (P < 0.01).

Borderline effects were demonstrated by larger than herd-average teat diameter (P = 0.04), udder asymmetry (P = 0.05) and increasing 2 min milk (P = 0.08). Results were compared to a previous study on the same data with log_e somatic cell count as the dependent variable. Inclusion of teat-end-to-floor distance in the genetic improvement scheme may increase the efficiency of genetic selection for mastitis resistance.  相似文献   

Geology. The Rodinia jigsaw puzzle     

Torsvik TH 《Science (New York, N.Y.)》2003,300(5624):1379-1381

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The liver parenchymal cells of rainbow trout (Salmo gairdneri) endocytose mannose-terminated glycoproteins     

Randi Fritzvold  Dr. Birgit H. Dannevig  Trond Berg 《Fish physiology and biochemistry》1989,6(6):367-375

A mannose-terminated glycoprotein,¹²⁵I-invertase, was taken up and degraded by isolated rainbow trout liver cells at 12°C. The uptake was inhibited by EGTA and no degradation occurred in the presence of ammonium ions. The liver cell suspension was fractionated by differential centrifugation in parenchymal and nonparenchymal cells, respectively. The parenchymal liver cells seemed to be the most active cells in uptake of labelled invertase bothin vitro andin vivo. Only negligible amounts of ligand were recovered in the nonparenchymal cells. Internalization of¹²⁵I-invertase at different temperatures was demonstrated indirectly by releasing surface-bound ligand with EGTA. Ligand was internalized even at 0°C in trout liver cells.In vitro uptake of¹²⁵I-invertase was inhibited by excess unlabelled invertase, by mannan and by N-acetylglucosamine.These data suggest that invertase is endocytosed by a mannose-specific pathway by the parenchymal liver cells of rainbow trout.  相似文献   

Optical properties of the pineal window of Atlantic salmon (Salmo salar L.)     

Trond Nordtug  Ole Kristia Berg 《Fish physiology and biochemistry》1990,8(6):541-546

The spectral composition and intensity of light penetrating different parts of fresh preparations of the upper part of the skull of Atlantic salmon (Salmo salar) (fork length 25–30 cm) was investigated. All measurements were made in an aqueous medium, by moving the tip of an optical fibre in a three dimensional lattice below preparations that were illuminated by a parallel light source from above. The intensity of the transmitted light showed a well-defined maximum just below the pineal groove. Light that penetrated the skull from a source vertically above was refracted to produce a focusing point in the approximate position of the pineal body. Light projected from angles of 45° relative to the vertical position was only slightly (25%) attenuated, thus indicating a wide acceptance angle. There was an almost uniform transmission of light (of 3%) between 500 and 700 nm. The transmittance of UV light (350 nm) was about 10% of that of green light. These differences are small when compared with the intensity range reported for the pineal light receptors. The transmission properties are discussed in relation to the known diurnal changes in the spectral composition of natural light.  相似文献   

The ratio between digestible protein and digestible energy affects accumulation and depuration of geosmin and 2-methylisoborneol (2-MIB) in Japanese seabass (Lateolabrax japonicus) raised in a recirculated aquaculture system     

Qiang Lu  Yuan Zou  Yuexing Zhang  Liying Huang  Haokun Liu  Zhiyong Dong  Xiaolong Yin  Trond Storebakken 《Aquaculture Research》2022,53(1):75-86

Actinobacteria and cyanobacteria accounted for less than 1% of total of bacteria in water in a recirculated aquaculture system (RAS) during a 15-week feeding trial with 0.11-g Japanese seabass. Resulting concentration of geosmin and 2-methylisoborneol (2-MIB) in RAS water was 169 and 45 ng L^?1, sufficient to produce strong off-flavour. The seabass were fed diets with 42%, 45% and 49% protein, and each protein level was supplemented with 15% or 18% lipid. Accumulation of off-flavours was independent of diet in fatty ventral tissue. Dietary protein significantly reduced off-flavours in lean, dorsal tissue. This was mainly rationalized by linear reduction in 2-MIB in response to increasing DP/DE and a strong, 2nd degree polynomial response in geosmin. The ratio between geosmin and 2-MIB was slightly higher at the beginning of a 10-day period with clean water and fasting, than what was observed throughout depuration. 2-MIB remained between 0.2 and 1 µg kg^?1 in dorsal tissue throughout depuration. Geosmin in ventral tissue ranged from 10 to more than 30 µg kg^?1at the termination of the feeding period and was reduced to a range from 6 to 20 µg kg^?1 by depuration.  相似文献