Embodied Resources in Fish and Shrimp Feeds          下载免费PDF全文

Sirirat Chatvijitkul  Claude E. Boyd  D. Allen Davis  Aaron A. McNevin 《Journal of the World Aquaculture Society》2017,48(1):7-19

Global averages were obtained for amounts of energy, land, water, wildfish, nitrogen, and phosphorus embodied in aquaculture feed ingredients. These data allowed amounts of these embodied resources to be calculated for typical feed formulations for channel catfish, Ictalurus punctatus; hybrid catfish, I. punctatus♀ × I. furcatus♂; Vietnamese catfish, Pangasius spp.; Atlantic salmon, Salmo salar; rainbow trout, Oncorhynchus mykiss; tilapia, Oreochromis spp.; whiteleg shrimp, Litopenaeus vannamei; and black tiger shrimp, Penaeus monodon. Embodied resource use per m.t. of feed varied among species: energy, 4.90–12.48 GJ/m.t.; land, 0.082–0.312 ha/m.t.; water, 502–1227 m³/m.t.; wildfish, 0–2880 kg/m.t.; nitrogen, 3.08–8.63 kg/m.t.; phosphorus, 1.16–5.62 kg/m.t. These calculations did not account for variations in site‐specific factors related to embodied resources and feed composition and use. But they suggest that reducing feed conversion ratio (FCR) by 0.1 unit for the seven species (species groups) could potentially reduce feed use by around 1.1 million tonne (Mt) while conserving 9.8 million GJ of energy, 270,000 ha of agricultural land, 1.4 billion m³ of freshwater, and 1.24 Mt of wildfish. Reduction of the FCR is a powerful means of lessening farm‐level production costs and negative impacts of feed production and use.  相似文献   

Once daily oral extended‐release hydrocodone as analgesia following tibial plateau leveling osteotomy in dogs          下载免费PDF全文

Ann E. Heffernan DVM  DACVS  Erin M. Katz DVM  Yiwen Sun PhD  Aaron K. Rendahl PhD  Michael G. Conzemius DVM  PhD  DACVS 《Veterinary surgery : VS》2018,47(4):516-523

  相似文献   

Subcutaneous administration of ciclosporin in 11 allergic cats – a pilot open‐label uncontrolled clinical trial          下载免费PDF全文

Sandra N. Koch  Sheila M. F. Torres  Sandra Diaz  Sophie Gilbert  Aaron Rendahl 《Veterinary dermatology》2018,29(2):107-e43

  相似文献   

Anaesthesia for liver transplantation in the pig     

J B Bowes  J Terblanche  J H Peacock  E J Immelman 《Research in veterinary science》1969,10(6):569-573

  相似文献   

Effect of carotene deficient rations and supplemental vitamin A on gain, feed utilization and liver vitamin A of calves     

W G Kirk  R L Shirley  J F Easley  F M Peacock 《Journal of animal science》1971,33(2):476-480

  相似文献   

Landscape attributes and life history variability shape genetic structure of trout populations in a stream network     

Helen M. Neville  Jason B. Dunham  Mary M. Peacock 《Landscape Ecology》2006,21(6):901-916

Spatial and temporal landscape patterns have long been recognized to influence biological processes, but these processes often operate at scales that are difficult to study by conventional means. Inferences from genetic markers can overcome some of these limitations. We used a landscape genetics approach to test hypotheses concerning landscape processes influencing the demography of Lahontan cutthroat trout in a complex stream network in the Great Basin desert of the western US. Predictions were tested with population- and individual-based analyses of microsatellite DNA variation, reflecting patterns of dispersal, population stability, and local effective population sizes. Complementary genetic inferences suggested samples from migratory corridors housed a mixture of fish from tributaries, as predicted based on assumed migratory life histories in those habitats. Also as predicted, populations presumed to have greater proportions of migratory fish or from physically connected, large, or high quality habitats had higher genetic variability and reduced genetic differentiation from other populations. Populations thought to contain largely non-migratory individuals generally showed the opposite pattern, suggesting behavioral isolation. Estimated effective sizes were small, and we identified significant and severe genetic bottlenecks in several populations that were isolated, recently founded, or that inhabit streams that desiccate frequently. Overall, this work suggested that Lahontan cutthroat trout populations in stream networks are affected by a combination of landscape and metapopulation processes. Results also demonstrated that genetic patterns can reveal unexpected processes, even within a system that is well studied from a conventional ecological perspective.  相似文献   

The application of artificial neural networks in plant protection*     

L. Peacock  S. Worner  J. Pitt 《EPPO Bulletin》2007,37(2):277-282

Artificial neural networks are powerful predictive tools that have the ability to detect and approximate non‐linear relationships from the data. In an explorative analysis, artificial neural networks were used to predict the geographic distribution of groups of polyphagous plant pests. Using climate variables as predictors, artificial neural network models were compared with binary logistic models for predicting insect distribution. Using bootstrapping, artificial neural networks were shown to predict insect presence and absence significantly better than the binary logistic regression models. Results from the study suggest that artificial neural networks have the potential for application in many areas of plant protection and biosecurity.  相似文献   

Rocky Mountain spotted fever in dogs and its differentiation from canine ehrlichiosis   总被引：4，自引：0，他引：4  

C E Greene  W Burgdorfer  R Cavagnolo  R N Philip  M G Peacock 《Journal of the American Veterinary Medical Association》1985,186(5):465-472

Rocky Mountain spotted fever (RMSF) or ehrlichiosis was diagnosed in dogs on the basis of specific immunofluorescent testing for each disease. Comparisons between clinical and laboratory findings were made between the 2 diseases. The incidence of RMSF tended to be more seasonal and it affected younger dogs. Purebred dogs appeared to be more susceptible to both diseases. In general, RMSF had a more rapid and severe course of clinical illness than did ehrlichiosis, but acute ehrlichiosis was difficult to differentiate from RMSF. Both diseases were characterized by fever, depression, lymphadenopathy, and signs of neurologic dysfunction; petechial hemorrhages or other signs of hemorrhagic diathesis were evident only in a small proportion of cases. Anemia, leukopenia, and thrombocytopenia were more common in dogs with ehrlichiosis, whereas those with RMSF more often had leukocytosis and thrombocytopenia. Hypoalbuminemia was found in dogs with both diseases, but those with ehrlichiosis usually had concurrent hyperglobulinemia. High serum alkaline phosphatase activity and serum cholesterol concentration, and low serum calcium concentration were more common in dogs with RMSF than with ehrlichiosis. Rising serum titers or positive direct immunofluorescence for Rickettsia rickettsii in skin biopsy specimens were used to confirm RMSF, whereas a single serum titer for Ehrlichia canis enabled detection of ehrlichiosis. In the absence of neurologic deficits and when dogs were treated with tetracycline, dogs with RMSF made a more rapid and consistent recovery than did dogs with ehrlichiosis.  相似文献   

Annualized diameter and height growth equations for Pacific Northwest plantation-grown Douglas-fir, western hemlock, and red alder   总被引：2，自引：0，他引：2  

Aaron R. Weiskittel  Sean M. Garber  Gregory P. Johnson  Douglas A. Maguire  Robert A. Monserud 《Forest Ecology and Management》2007,250(3):266-278

Simulating the influence of intensive management and annual weather fluctuations on tree growth requires a shorter time step than currently employed by most regional growth models. High-quality data sets are available for several plantation species in the Pacific Northwest region of the United States, but the growth periods ranged from 2 to 12 years in length. Measurement periods of varying length complicate efforts to fit growth models because observed growth rates must be interpolated to a common length growth period or those growth periods longer or shorter than the desired model time step must be discarded. A variation of the iterative technique suggested by Cao [Cao, Q.V., 2000. Prediction of annual diameter growth and survival for individual trees from periodic measurements. Forest Sci. 46, 127–131] was applied to estimate annualized diameter and height growth equations for pure plantations of Douglas-fir, western hemlock, and red alder. Using this technique, fits were significantly improved for all three species by embedding a multi-level nonlinear mixed-effects framework (likelihood ratio test: p < 0.0001). The final models were consistent with expected biological behavior of diameter and height growth over tree, stand, and site variables. The random effects showed some correlation with key physiographic variables such as slope and aspect for Douglas-fir and red alder, but these relationships were not observed for western hemlock. Further, the random effects were more correlated with physiographic variables than actual climate or soils information. Long-term simulations (12–16 years) on an independent dataset using these annualized equations showed that the multi-level mixed effects models were more accurate and precise than those fitted without random effects as mean square error (MSE) was reduced by 13 and 21% for diameter and height growth prediction, respectively. The level of prediction error was also smaller than an existing similar growth model with a longer time step (ORGANON v8) as the annualized equations reduced MSE by 17 and 38% for diameter and height growth prediction, respectively. These models will prove to be quite useful for understanding the interaction of weather and silviculture in the Pacific Northwest and refining the precision of future growth model projections.  相似文献   

West Nile virus in North America: perspectives on epidemiology and intervention     

Reisen W  Brault AC 《Pest management science》2007,63(7):641-646

West Nile virus (WNV) invaded New York in 1999 and rapidly swept across the North American continent to the West Coast, north into southern Canada and south into Latin America, with minimal genetic change. Regional epidemics in equines and humans typically have included a year of viral introduction with minimal activity, successful overwintering, explosive amplification to epidemic levels the following year and then rapid subsidence. Overwintering possibly included long-term mosquito or avian infections, continued low-level transmission at southern latitudes and dispersal by south-north migrants. Explosive amplification has been associated with infections in several corvid species and other urban birds that produce elevated viremias capable of efficiently infecting even moderately susceptible mosquito species. Intervention has included mass vaccination of equines, and proactive and reactive mosquito control. Proactive mosquito control in areas with established infrastructure has been successful in reducing case incidence.  相似文献