Metabolic resistance to S‐metolachlor in two waterhemp (Amaranthus tuberculatus) populations from Illinois,USA     

Seth A Strom  Aaron G Hager  Nicholas J Seiter  Adam S Davis  Dean E Riechers 《Pest management science》2020,76(9):3139-3148

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Use of Dried Fermented Biomass as a Fish Meal Replacement in Practical Diets of Florida Pompano,Trachinotus carolinus     

Melanie A. Rhodes  Yangen Zhou  D. Allen Davis 《Journal Of Applied Aquaculture》2013,25(1):29-39

Substitution of fish meal (FM) as a protein source in aquaculture diets is required to reduce cost and promote a sustainable industry. Potential protein sources include a range of traditional products from agricultural production such as plant or animal proteins. However, there are also a number of manufacturing coproducts, including bacterial dried fermented biomass (DFB,) for which there is an increased interest. Hence, the objective of this study was to evaluate DFB as a replacement for FM in practical diets for Florida pompano, Trachinotus carolinus. Four diets were prepared in which different levels of FM (15%, 10%, 5%, and 0% of the diet) were replaced with DFB (0%, 4.27%, 8.54%, and 12.82%) on an iso-nitrogenous and iso-lipidic basis, to contain 40% crude protein and 10% lipid. A 10-week growth trial was conducted in a recirculating system consisting of 12 indoor 1.0 m³ tanks, stocked with 20 juvenile pompano (mean initial weight 8.1 g) per tank. There were no significant differences in final weight (64.5 g?79.5 g), survival (81.7%–96.7%), percent weight gain (711.6%–879.0%), FCR (2.1–2.0), or thermal-unit growth coefficient (0.1013?0.1149), regardless of the levels of dietary FM or DFB tested. Based on these results, it is recommended that DFB can be included up to 12.8% in practical diets for Florida pompano without significantly reducing growth performance. The response to higher levels of DFB inclusion should be evaluated.  相似文献   

Optimal chemical triploid induction in geoduck clams, Panopea abrupta, by 6-dimethylaminopurine     

Brent Vadopalas  Jonathan P. Davis   《Aquaculture (Amsterdam, Netherlands)》2004,230(1-4):29-40

The development of geoduck culture techniques coupled with increased market demand during the past decade led to cultured intertidal geoduck beds, over which concerns have arisen regarding the potential genetic risk posed by the reproductive contribution of hatchery outplants to wild stocks. Although an ongoing study to determine the genetic stock structure of Puget Sound geoducks has yet to yield definitive results, sterile triploids would enable geoduck culture to proceed irrespective of any genetic differences found, and may increase rate of growth. At 15 °C and salinity of 30‰, we evaluated the suitability of cytochalasin B (CB) and 6-dimethylaminopurine (6-DMAP) for triploid induction in geoducks. Parallel tests of induction agent, start time, duration, and concentration were conducted on the same gamete pool. We found optimal triploid induction (92%) and suitable survivorship (30%) resulted from a 600 μM 6-DMAP treatment. This work enables the future examination of the efficacy of triploid induction for conferring sterility and increasing growth rate in this commercially valuable species.  相似文献   

Development of plant‐based diets and the evaluation of dietary attractants for juvenile Florida pompano,Trachinotus carolinus L.          下载免费PDF全文

M.A. Rhodes  Y. Zhou  G.P. Salze  T.R. Hanson  D.A. Davis 《Aquaculture Nutrition》2017,23(5):1065-1075

Sustainable and profitable commercial aquaculture production of marine fish species is dependent on the development of sustainable protein sources as substitutes for expensive animal meals such as fishmeal (FM). Previous Florida pompano Trachinotus carolinus studies have indicated that poultry by‐product meal (PBM) and meat and bone meal can be used to produce a FM‐free diet if suitable levels of nutrients (such as taurine) are included in the diets. In this study, we attempted to develop an all‐plant protein diet by removing the animal proteins in practical diets for pompano by substituting back select ingredients. A series of eight FM‐free diets were formulated, four systematically replaced soybean meal (SBM) with soy protein concentrate (SPC) and four replaced PBM with SPC. Based on the results, there is no clear disadvantage to the use of SPC as a replacement for SBM. However, the complete removal of PBM resulted in reduced performance. Two additional growth trials were conducted to supplement additional amino acids including glycine, valine and histidine, a proprietary chemical attractant mix, fish protein concentrate and squid hydrolysate to improve the growth of pompano when fed all‐plant protein diets. The only improvement in performance occurred with the squid hydrolysate. These results demonstrate that using soybean meal, soy protein concentrate and corn gluten meal as the primary protein sources, a plant‐based feed formulation can be developed, but the removal of all animal proteins is not yet feasible.  相似文献   

Can placement of seed away from relic stubble limit Rhizoctonia root rot in direct-seeded wheat?     

Ryan A. Davis  David Huggins  R. James Cook  Timothy C. Paulitz   《Soil & Tillage Research》2008,101(1-2):37-43

Rhizoctonia root rot of wheat can be a problem in no-till systems, especially during the transition from conventional tillage. There are no effective chemical controls or resistant varieties, leaving only cultural methods to manage this disease. In a no-till system, residue and inoculum of soilborne pathogens are not moved by cultivation, therefore the inoculum may be concentrated in the seeding row of the previous year. Using GPS tracking systems with sub-meter accuracy, the seeding row could be placed away from the row of the previous year. We tested the hypothesis that seeding away from the relic row may reduce Rhizoctonia root rot. In two field experiments, plants were sampled at three distances from the seed row, as well as from fumigated plots. Intact soil cores were also removed from the field, planted with seeds at various distances from the previous row, and grown in the greenhouse under controlled conditions. Pasteurized cores served as controls. Disease levels were higher in the field in the second year, but there was no consistent effect of seed row placement on disease or plant parameters. However, soil fumigation and pasteurization had significant effects, indicating that soilborne pathogens were active. Inoculum of Rhizoctonia is not produced in the crowns and lower stems of the plant, but the pathogen survives in living and dead roots of the previous year crop, volunteers, and grassy weeds. Thus, high inoculum densities may be present in between the relic rows, as well as within the rows. If this is the situation with Rhizoctonia, precision placement of seed rows would not be efficacious.  相似文献   

Relationships between soil and foliar nutrients in young densely planted mini-plots of Pinus radiata and Cupressus lusitanica     

Murray R. Davis  Graham Coker  Roger L. Parfitt  Robyn Simcock  Peter W. Clinton  Loretta G. Garrett  Michael S. Watt 《Forest Ecology and Management》2007,240(1-3):122-130

The long-term nature of forest crop rotations makes it difficult to determine impacts of forestry on soil nutrients that might be depleted by forest growth. We used small scale, highly stocked plots to compress the length of the rotation and rapidly induce nutrient depletion. In the study, two species (Pinus radiata D. Don and Cupressus lusitanica Miller) are compared under two disturbance regimes (soil undisturbed and compacted), and two fertiliser treatments (nil and plus fertiliser), applied in factorial combination at 33 sites, covering the range of climatic and edaphic variation found in plantation forests across New Zealand. To assess our ability to rapidly highlight important soil properties, foliar nutrient concentrations were determined 20 months after planting. It was hypothesised that the densely planted plots, even at a young age, would create sufficient pressure on nutrient resources to allow development of relationships between properties used as indicies of soil nutrient availability and foliar nutrient concentrations. For both species significant relationships between foliar nutrients and 0–10 cm layer soil properties from unfertilised plots were evident for N (total and mineralisable N) and P (total, acid extractable, organic, Bray-2 and Olsen P). With the exception of Ca in C. lusitanica, foliar K, Ca and Mg were correlated with their respective soil exchangeable cation measures. The results thus confirm the utility of the experimental approach and the relevance of the measured soil properties for forest productivity.

In unfertilised plots foliar N and P concentrations in P. radiata exceeded those in C. lusitanica, the differences being eliminated by fertiliser application. Foliar N/P ratios in P. radiata also exceeded those in C. lusitanica. In contrast to N and P, foliar K, Ca and Mg concentrations were all higher in C. lusitanica, the difference being particularly marked for Ca and Mg. P. radiata contained substantially higher concentrations of the metals Zn, Mn and Al than C. lusitanica, whereas the latter contained higher B concentrations. Possible reasons for differences between species in foliar nutrient concentrations are discussed.  相似文献   

Temperate zone coastal seascapes: seascape patterning and adjacent seagrass habitat shape the distribution of rocky reef fish assemblages     

Swadling  Daniel S.  Knott  Nathan A.  Rees  Matthew J.  Davis  Andrew R. 《Landscape Ecology》2019,34(10):2337-2352

Landscape Ecology - Whilst the composition and arrangement of habitats within landscape mosaics are known to be important determinants of biodiversity patterns, the influence of seascape patterning...  相似文献   

Phosphorylation by p38 MAPK as an alternative pathway for GSK3beta inactivation     

Thornton TM  Pedraza-Alva G  Deng B  Wood CD  Aronshtam A  Clements JL  Sabio G  Davis RJ  Matthews DE  Doble B  Rincon M 《Science (New York, N.Y.)》2008,320(5876):667-670

Glycogen synthase kinase 3beta (GSK3beta) is involved in metabolism, neurodegeneration, and cancer. Inhibition of GSK3beta activity is the primary mechanism that regulates this widely expressed active kinase. Although the protein kinase Akt inhibits GSK3beta by phosphorylation at the N terminus, preventing Akt-mediated phosphorylation does not affect the cell-survival pathway activated through the GSK3beta substrate beta-catenin. Here, we show that p38 mitogen-activated protein kinase (MAPK) also inactivates GSK3beta by direct phosphorylation at its C terminus, and this inactivation can lead to an accumulation of beta-catenin. p38 MAPK-mediated phosphorylation of GSK3beta occurs primarily in the brain and thymocytes. Activation of beta-catenin-mediated signaling through GSK3beta inhibition provides a potential mechanism for p38 MAPK-mediated survival in specific tissues.  相似文献   

Further studies on memory formation in the goldfish     

Agranoff BW  Davis RE 《Science (New York, N.Y.)》1967,158(3800):523

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Response of Pacific White Shrimp,Litopenaeus vannamei,to Three Sources of Solvent Extracted Soybean Meal     

Xuezhi Zhu  D. Allen Davis  Luke A. Roy  T. M. Samocha  J. P. Lazo 《Journal of the World Aquaculture Society》2013,44(3):396-404

Three sources of soybean meal (SBM) were biochemically characterized and evaluated in diets for juvenile Litopenaeus vannamei. Three biological techniques were utilized to evaluate the nutritional quality of the meals including an outdoor growth trial as well as determination of in vivo apparent digestibility and in vitro digestibility including pepsin digestibility (0.0002%), pH Stat degree of hydrolysis, and immobilized digestive enzyme assay (IDEA). The growth trial was conducted over a 10‐wk period using soybean meal as the primary protein source with each meal being included at 54–58% of the diet based on an equal protein inclusion. At the conclusion of the growth trial there were no significant differences between the test diets indicating equivalent biological availability under practical conditions. The in vivo digestibility trial utilized chromic oxide as the inert marker and 70:30 replacement techniques resulted in typical results. Apparent protein digestibility (APD) and apparent energy digestibility (AED) of the diets ranged from 66.8 to 80.2% and 65.4 to 74.7%, respectively. Ingredient digestibility values for protein and energy ranged from 78.8 to 93.5% and 60.5 to 85.0%, respectively. One of the three SBM evaluated had numerically lower protein digestibility and significantly lower energy digestibility than the other two meals .  相似文献