Effects of Concentrate Level on Carcass Composition,Tenderness and Growth Rate of Angus × NRF and Limousin × NRF Bulls     

Rune Rødbotten  Kjell Ivar Hildrum  Jan Berg 《Acta Agriculturae Scandinavica, Section A - Animal Sciences》2013,63(2):72-80

In total, 56 bulls of Angus 2 NRF or Limousin 2 NRF were fed two levels (either 2.5 or 5.0 kg animal -1 day -1 ) of concentrate from 12 weeks of age to slaughter in a 2 2 2 factorial design with cross-breed and concentrate level as fixed factors. The concentrate was a mixture with barley, oats, wheat, soyabean and molasses as main components. In addition, the animals had ad libitum access to grass silage. As expected, the bulls fed the high concentrate diet had higher growth rate than bulls fed moderate level of concentrate. Angus 2 NRF bulls fed the high level of concentrate showed the highest growth rate of the four subgroups and were on average slaughtered at the age of 15 months. Limousin 2 NRF bulls fed the moderate level of concentrate were the subgroup with the lowest growth rate and needed 20 months to reach the target slaughter weight, which on average was 280 and 340 kg for Angus 2 NRF and Limousin 2 NRF, respectively. Although the animals at the high concentrate level had a greater intake of energy day -1 , there was no significant difference in feed conversion calculated as FUm kg -1 gain between the subgroups. The Limousin cross-breeds had significantly higher relative proportions of muscle in the carcass, but less bone and fat than the Angus cross-breeds. Consequently, the Limousin 2 NRF bulls achieved better muscularity grading in the EUROP system than the Angus 2 NRF bulls. Concentrate level yielded different fatness scores in the EUROP system, while breed did not. The correlation between carcass weight and psoas major or longissimus dorsi muscles was stronger for the former muscle. There was a tendency for Angus 2 NRF bulls fed the moderate concentrate level to have more tender longissimus muscle than the other subgroups, but this difference was not significant.  相似文献   

Increased dietary protein‐to‐lipid ratio improves survival during naturally occurring pancreas disease in Atlantic salmon,Salmo salar L.     

Jens‐Erik Dessen  Turid Mrkre  Jan Ivar Bildy  Stig N. Johnsen  Lars Thomas Poppe  Bjarne Hatlen  Magny S. Thomassen  Kjell‐Arne Rrvik 《Journal of fish diseases》2019,42(1):21-34

This study demonstrated that increased dietary protein‐to‐lipid ratio (P/L‐ratio) improved survival of farmed Atlantic salmon naturally affected by pancreas disease (PD). In addition to diet, body weight (BW) and delousing mortality prior to the PD outbreak also contributed significantly (p < 0.05) to explain the observed variation in PD‐associated mortality. Subsequent to the PD outbreak, large amount of fish failed to grow and caused thin fish with poor condition (runts). At the end of the trial, significantly (p < 0.05) lower amounts of runt fish and increased amount of superior graded fish where detected among fish fed increased P/L‐ratio and within the fish with the largest BWs prior to PD. Diet, BW and delousing mortality contributed significantly (p < 0.05) to explain the variation in the amount of superior graded fish, whereas BW and diet explained the variation in the amount of runt fish. A significant (p < 0.01) negative linear relationship was observed between the amount of superior graded fish and the total mortality, whereas a positive linear relationship was detected between percentage of fillets with melanin and the total mortality. Thus, increased dietary P/L‐ratio seem to reduce the mortality and impaired slaughter quality associated with PD.  相似文献   

Cover Image     

Toni Erkinharju  Guro Strandskog   yvind Vgnes  Ivar Hordvik  Roy A. Dalmo  Tore Seternes 《Journal of fish diseases》2019,42(12):i-i

  相似文献   

Effect of starvation on the survival,injury, and weight of adult snow crab,Chionoecetes opilio     

Sten Ivar Siikavuopio  Gunhild Seljehaug Johansson  Philip James  Grete Lorentzen 《Aquaculture Research》2019,50(2):550-556

In this study, the effects of feeding (F) and starvation (S) on survival, injury, and weight of captive male snow crab were examined. The experiment was carried out with three replicates of each treatment. Each replicate had 11 individually tagged crabs (average weight of 650 g ± 37 SE) per tank (replicate) in a total of six circular tanks (500 L), with stocking densities of 14 kg/m. The experiment ran for 100 days and the animals were exposed to ambient seawater temperatures ranging from 4.4ºC to 5.4ºC during the trial period. There were no significant differences in wet weight between the groups at the start or at the end of the experiment. However, the hepatopancreas index (HI) significantly decreased in both groups from 6.1% at the start to, respectively, 4.6% (F) and 3.2% (S) at day 100. The S group had a significantly lower HI than the F group. Only one animal died during the experiment (day 100, F). The frequencies of injuries were similar in all groups. The results show that adult male snow crab can be stored for minimum 100 days (with or without feeding) with relatively low risk of physical injury, or mortality due to social interactions.  相似文献   

Long-term effects of stocking density on somatic growth,gonad index and survival of the juvenile sea urchin, <Emphasis Type="Italic">Strongylocentrotus droebachiensis</Emphasis>     

Sten I. Siikavuopio  Philip J. James 《Aquaculture International》2011,19(4):741-747

Juvenile Strongylocentrotus droebachiensis (average wet weight = 4.0 g) were held at three initial stocking densities (15, 30 and 60 animals per tray, which equates to 0.25, 0.5 and 1 kg sea urchins/m² surface area, respectively) under constant light and temperature conditions (LD 24:0 and 8.8°C) for 380 days. The somatic growth and survival of the urchins were monitored during this period, and the gonad index (GI) was measured at the conclusion of the experiment. The sea urchins in the two lowest stocking density groups had 100% survival after 380 days in contrast to the highest stocking density group, which only had 67% survival at the conclusion of the experiment. Somatic growth was significantly higher in the lowest density group than in the medium density group, and this in turn was significantly higher than in the high-density group. The injury occurrence was highest in the high-density group (20%), lower in the medium group (7%), and there were no injuries observed (0%) in the low density groups. There were no significant differences in GI between the groups at the end of the experiment. In conclusion, the present study showed that stocking density has significant effects on somatic growth and survival of juvenile green sea urchin, S. droebachiensis and should be taken into consideration when designing sea urchin holding systems.  相似文献   

Control of light condition affects the feeding regime and enables successful eye migration in Atlantic halibut juveniles     

Torstein Harboe  Anders Mangor-Jensen  Mari Moren  Kristin Hamre  Ivar Rnnestad 《Aquaculture (Amsterdam, Netherlands)》2009,290(3-4):250-255

Incomplete eye migration is one of the major problems in intensive production of juvenile Atlantic halibut. More than 60% of an average juvenile population reared according to best practice suffers from this abnormality. In commercial production, these fish are discharged and represent a substantial economic loss and a large welfare problem. In the present investigation it is demonstrated that by controlling diurnal light and darkness periods together with a meal based feeding regime, incomplete eye migration can be dramatically reduced in production systems for Atlantic halibut.Control groups were reared under continuous light conditions, whereas the experimental groups were given 7 h of darkness and 17 h of light during a 24 hour cycle, in a period lasting from 12 to 35 days post first-feeding. Otherwise both groups were reared under continuous light conditions. All larvae were fed short time enriched Artemia supplied two times daily.The experimental conditions did not affect the overall growth or survival up to day 85 after first feeding. However, 27 ± 3% of the fry reared under continuous light conditions had complete eye migration, whereas in juveniles reared under shifting light and darkness conditions, complete eye migration was 85 ± 7%. These results represent a major improvement in production systems for Atlantic halibut juveniles.  相似文献   

Comparative growth study of wild- and hatchery-produced Arctic charr (Salvelinus alpinus L.) in a coldwater recirculation system   总被引：1，自引：1，他引：0  

Sten Ivar Siikavuopio  Steinar Skybakmoen  Bjrn-Steinar Sther 《Aquacultural Engineering》2009,41(2):122-126

The growth performance of Arctic charr of wild (W) and hatchery (H) origin was compared in a commercial coldwater recirculation system (Villmarksfisk, Bardu, 68°N, 19°E, Norway). The initial individual body mass was 115 g and similar between groups. The rearing temperature was 9.2 °C and the fish were held under continuous light (24:0 L:D). At the end of the experiment (day 240), the average body mass of the H fish was 451 g compared to 231 g in the W fish. The accumulated mortality of wild Arctic charr was about 40%; 10 times higher than the mortality of hatchery-produced Arctic charr (4%). The difference in growth performance and survival rate impose a great disadvantage of using this wild caught fish as compared to commercially available hatchery-produced Arctic charr in coldwater recirculation system. However, further improvements in the production chain (catching, live transport, quarantine, size grading, etc.) may still make production of wild caught Arctic charr profitable, especially as it demands a higher price in niche markets.  相似文献