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1.
A Comparison of the Effects of Two Prey Enrichment Media on Growth and Survival of Pacific Bluefin Tuna,Thunnus orientalis,Larvae 下载免费PDF全文
Maria S. Stein Daniel Margulies Jeanne B. Wexler Vernon P. Scholey Katagiri Ryo Tomoki Honryo Tsukasa Sasaki Angel Guillen Yasuo Agawa Yoshifumi Sawada 《Journal of the World Aquaculture Society》2018,49(1):240-255
Three experiments were conducted to investigate the growth, survival, and standardized cohort biomass of Pacific bluefin tuna, Thunnus orientalis, larvae fed nutritionally enhanced prey during the first week of feeding using two commonly used, commercially available enrichment media, AlgaMac Enrich and Marine Glos. T. orientalis larvae exhibited exponential growth in standard length and dry weight. The daily specific growth rates in length and weight are the first reported for T. orientalis larvae and the averages ranged from 3.8 to 4.1% and 27.5%, respectively, for larvae in the AlgaMac treatment and from 4.1 to 6.1% and 31.5%, respectively, in the Marine Glos treatment. Average daily growth rates in length ranged from 0.16 to 0.23 mm/d for larvae in the AlgaMac treatment and from 0.17 to 0.27 mm/d for those in the Marine Glos treatment. Daily growth rates in length were similar to those reported for other tuna larvae reared in the laboratory but slower than most published estimates for larval tunas in situ at similar water temperatures. Mean prey number per gut was positively associated with mean prey level in the tank. Both enrichment media appear to be good sources of nutritional improvement of planktonic prey for T. orientalis larvae. 相似文献
2.
Holding wild Snow crab,Chionoecetes opilio: effects of stocking density and feeding on survival and injury 下载免费PDF全文
Sten Ivar Siikavuopio Philip James Bjørn Ronald Olsen Tor Evensen Atle Mortensen Stein Harris Olsen 《Aquaculture Research》2017,48(4):1590-1595
In this study the effects of different stocking densities on survival, injury and weight of captive male snow crab were examined. The first experiment (I) was carried out in square plastic tanks (700 L) with stocking densities of 100 (L), 150 (M) and 200 kg m?3 (H) for 30 days. In a second experiment (II) snow crabs were kept at a stocking density of 50 kg m?3 and were either fed (F) or not fed (S) for the same period of 35 days. The last experiment (III), was carried out with stocking densities of 25 kg m?3 for 21 days with two groups, one with inactivated claw and one without rubber bands, with three replicates per treatment. In the first experiment mortality (H = 27, M = 26 and L = 36%) and occurrence of injuries (H = 27, M = 20 and L = 16%) were high in all groups. The weight loss during the experimental period was; H = 15.3, M = 10.9 and L = 15.5 g, and was not significant different between the groups. In experiment II the mortality (F = 13% and S = 14%) and injuries were lower (F = 12% and S = 17%). The average weight increased in the fed treatment and decreased in the starved treatments. In the last experiment there was no mortality in any of the groups and the levels of injury were low (5% and 7%). The results show that adult male snow crab cannot be stored at densities equal to or higher than 25 kg m?3 for 3 weeks without risk of mortality. 相似文献
3.
Hanne Fjerdingby Olsen Saija Tenhunen Nils Ivar Dolvik Dag Inge Våge Gunnar Klemetsdal 《Acta Agriculturae Scandinavica, Section A - Animal Sciences》2020,69(1-2):118-126
ABSTRACTThe Fjord horse originates from Norway but forms a global population due to several small populations in foreign countries. There exists no information about the additive relationship and the genetic variance between these subpopulations. By collecting blood samples from Norwegian and Swedish Fjord horses, a sample of 311 Norwegian and 102 Swedish horses gave 485,918 SNPs available for analysis. Their inbreeding coefficients were calculated and compared to the pairwise coancestry and the shared genomic segments. The effective population size was almost similar with the two methods in the Norwegian Fjord horse population (63 and 71), but very different in the Swedish population (269 and 1136) and unprecise due to a much smaller number of observations. The study showed that coancestry from shared genomic segments can be used to estimate additive genetic relationship and genetic variation within and between the global populations of the Fjord horse. 相似文献
4.
<正>近期伊利诺伊大学的J.A.Almeida博士、 Hans H.Stein博士以及Carsten Pedersen博士联手展开体重对于标准化回肠蛋白质和氨基酸吸收率的影响试验,结论证明,20 kg以下的仔猪回肠对于粗蛋白和氨基酸的吸收率比20~50 kg的育成猪和50~110 kg的育肥猪低。而且同一猪群的不同猪只也表现出吸收率的差异性。例如,在测定的300只仔猪中粗蛋白和氨基酸的吸收率 相似文献
5.
Minh Van Nguyen Marit Espe Louis E. C. Conceio Hoang Minh Le Manuel Yúfera Sofia A. D. Engrola Ann‐Elise Olderbakk Jordal Ivar Rnnestad 《Aquaculture Nutrition》2019,25(2):495-507
This study determined impacts of dietary methionine concentrations at two temperatures on growth, feeding efficiency and N‐metabolites in juvenile cobia. Methionine concentrations of the experimental diets were deficient (M9; 9 g/kg), sufficient (M12; 12 g/kg) and surplus (M16, 16 g/kg). Water temperature was normal (30°C) or elevated (34°C). Twenty cobia in triplicate tanks were fed the experimental diets for 6 weeks. Both methionine and temperature affected cobia's growth and feeding efficiency. Cobia fed M9 performed lower than the fish fed M12 and M16 diets. Additionally, cobia reared at 34°C performed poorer than at 30°C, probably due to lower voluntary feed intake in the fish reared at 34°C. Protein efficiency ratio and protein productive value in cobia fed M9 diet were less than M12 or M16 diets. This was confirmed with the improved retentions of indispensable amino acids (AAs). No interactions between methionine and temperature were observed in growth and protein accretion. At 30°C, CF improved, while HSI and VSI declined upon methionine supplementation levels. Of which an interaction between temperature and methionine was present. Plasma, muscle and liver free AA and N‐metabolites were affected by methionine and temperature. Furthermore, temperature affected cobia's lipid class composition, resulting in increased phospholipids and cholesterol at 34°C. 相似文献
6.
Measuring density effects on growth and survival of two size classes of juvenile sea urchins (Strongylocentrotus droebachiensis) held in sea‐based holding systems and impacts on holding system design and management 下载免费PDF全文
Assessing density in intensive sea urchin culture systems by measuring the percentage coverage of available surface area is an effective means of calculating the available space within a holding system, the proximity of the animals in the system to each other and the probable effects of the stocking density. The results of this study show that density plays a critical role in regard to both somatic growth (increase in test diameter measured in millimetres) as well as mortality of juvenile sea urchins ranging in size from 5 mm to 26 mm test diameter (the size range tested in the current experiments). These effects appear to be greater for smaller urchins. The critical percentage coverage densities are in the order of 50%‐60% coverage for juvenile sea urchins, and the authors advise farmers growing Strongylocentrotus droebachiensis to maintain stocking densities below this point and to reduce the stocking densities as and when stocks reach these critical density points. Percentage cover must be constantly monitored as the results from this study indicate that the growth rates of juvenile urchins can alter percentage coverage rapidly and reductions in density may be required as frequently as every 3‐4 months at the early juvenile stage. Holding system design should take these factors into account and incorporate a method of rapidly reducing stocking densities with minimal stress and handling of sea urchin stocks. 相似文献
7.
Asparagus is especially suitable for polyploidy breeding. The aim is to develop clone-based hybrid varieties, in particular male 4 × varieties. For this purpose, genetically divergent diploid idiotypes * * Idiotye (according to Reiger et al. 1976) is the sum of total hereditary determinants of an organism, consisting of its genotype (all determinants localized in the chromosomes) and its plasmotype (all determinants localized extra-chromosomally).
) are subjected to mitotic or meiotic polyploidization. In developing hybrid partners, special attention is paid to resistance in addition to yield and quality characters. Early diagnoses are applied in selection so as to shorten breeding times. Somaclonal variations may occur relatively often on in vitro propagation; these need to be eliminated. Triplex and quadruplex type males are suitable for paternal hybrid partners. Strong inbreeding depressions need to be avoided in their production. 相似文献
) are subjected to mitotic or meiotic polyploidization. In developing hybrid partners, special attention is paid to resistance in addition to yield and quality characters. Early diagnoses are applied in selection so as to shorten breeding times. Somaclonal variations may occur relatively often on in vitro propagation; these need to be eliminated. Triplex and quadruplex type males are suitable for paternal hybrid partners. Strong inbreeding depressions need to be avoided in their production. 相似文献
8.
Mass propagation of the German cockroach in refuse tips may result in an increased emigration of this species into the surrounding area of the tip and thus in a heavy infestation of nearby buildings. Therefore, knowledges about the migration behavior are important when refuse tips are managed or projected. The influence of several environmental factors (as sun, day time, wind, temperature, season, light intensity) on the running behavior of the German cockroach was investigated under outdoor conditions. The most important results are as follows:
- The reaction of young larvae (especially of L1 and L2) on the investigated factors differs considerably from that of older larvae and adults. As the young larvae do not emigrate, their behavior can be neglected in respect to the questions discussed here.
- During sunshine, the position of the sun is primarily responsible for the direction of the migration. The highest percentage of the cockroaches walks directly towards the sun or a few grade right and left from the sun. When the sun is covered by clouds, the variation in the running direction is very high and many cockroaches migrate even into the direction opposite to the sun.
- From morning to evening, the main migration direction is shifting from east to west, following the position of the sun.
- Wind direction (at speeds of less than 5 m/sec.) and temperature (within the activity range of the cockroaches from approximately 18 to more than 30°C) have no recognizable influence upon the migration direction.
- The clearest reaction of the running cockroaches towards the position of the sun was noticed during the main migration-time in the year (June and July).
- The results of these investigations confirm former findings made in the field during a mass emigration of the German cockroach from a refuse tip.
9.
W. Stein 《Journal of pest science》1961,34(6):87-89
Zusammenfassung Um den Einfluß verschiedener Insektizide und Fungizide auf Schlupfwespen der GattungTrichogramma zu prüfen, wurde deren Parasitierungsleistung bei Dauerkontakt mit dem betreffenden Mittel untersucht. Mit unbehandelten Apfelzweigen wurden solche verglichen, die mit den Fungiziden Dithane, Orthozid 50 und Ferbam F 40 bzw. den Insektiziden Ryania, Basudin R, Dipterex, Thiodan oder Metasystox gespritzt waren. Das Alter der Rückstände betrug 0, 24 bzw. 72 Stunden.Alle drei genannten Fungizide reduzierten die Parasitierung in den verschiedenen Varianten erheblich.Das spezifisch gegen Tortriziden wirkende Ryania zeigte praktisch keine toxische Wirkung. Die Anzahl der parasitierten Eier lag entweder gleich hoch wie bei den unbehandelten Kontrollen oder in einem Fall sogar erheblich höher.Die übrigen 4 Insektizide töteten die Schlupfwespen in kurzer Zeit ab, so daß in keinem Fall eine Parasitierung erzielt werden konnte.Noch nicht abgeschlossene Lebensdauerversuche bestätigen die erzielten Ergebnisse.Die Möglichkeiten und Probleme einer gemeinsamen Anwendung vonTrichogramma und Schädlingsbekämpfungsmitteln im Obstbau werden diskutiert.
Dem Leiter des Instiltutes für Biologische Schädlingsbekämpfung, Herrn ORR. Dr. J. Franz bin ich für wertvolle Hinweise und jederzeitige Hilfe dankbar. — Durchgeführt mit Unterstützung der Deutschen Forschungsgemeinschaft. 相似文献
Summary To examine the influence of various insecticides and fungicides upon egg-parasites of the genusTrichogramma, their efficiency of parasitization at permanent contact with the concerning pesticide was checked. With untreated applebranches were compared those ones, which were treated with the fungicides Dithane, Orthozid 50 or Ferbam F 40 and the insecticides Ryania, Basudin R, Dipterex, Thiodan or Metasystox resp.All three fungicides reduced the parasitization in the different variations considerably.Ryania, which shows a specific effect against tortricides, had no toxical influence on,Trichogramma.The other four insecticides killed the parasites within a short time, so that in no case a parasitization could be achieved.Investigations concerning the duration of life confirmed the result of the parasitization investigations.The possibilities and problems of a combined application ofTrichogramma and pesticides in apple orchards are discussed.
Dem Leiter des Instiltutes für Biologische Schädlingsbekämpfung, Herrn ORR. Dr. J. Franz bin ich für wertvolle Hinweise und jederzeitige Hilfe dankbar. — Durchgeführt mit Unterstützung der Deutschen Forschungsgemeinschaft. 相似文献
10.
Andrius Kuliešis Stein M. Tomter Claude Vidal Adrian Lanz 《Annals of Forest Science》2016,73(4):857-869