The Effect of Temperature on Feed Consumption and Nutrient Absorption in Procambarus clarkii and Procambarus zonangulus     

Suzanne L.  Croll Stephen A.  Watts 《Journal of the World Aquaculture Society》2004,35(4):478-488

Feeding characteristics of acclimated red swamp crayfish Procambarus clarkii and white river crayfish Procambarus zonangulus were determined at 8, 14, 20, 26, and 32 C. Food consumption rates of crayfish were directly related to temperature. Feeding was minimal at 8 C. At 14 CP. zonangulus consumed significantly more feed (5.5% body weight (BW/d) than P. clarkii (1.8% BW/d). At 32 C P. clarkii consumed significantly more feed (23% BW/d) than P. zonangulus (10% BW /d), reflecting species-specific thermal optimums for feeding. Differences in food consumption rates correspond to differences in the geographical distributions of these two species. Dry matter absorption rates ranged from 55% to 75% for both species without significant temperature effect. Patterns of protein and carbohydrate absorption were similar in P. clarkii and P. zonangulus. Protein absorption efficiency decreased from 45% to 10% as temperature increased from 8 C to 32 C. The total amount of protein absorbed increased seven- to ten-fold as temperature increased. Soluble carbohydrate absorption efficiency was reduced at low temperatures. However, absorption efficiency increased approximately five-fold as temperature increased from 14 C to 20 C, but did not change substantially as temperature was increased to 32 C. The total amount of carbohydrate absorbed increased approximately 15- to 26-fold as temperature increased. The protein to carbohydrate utilization ratio was similar between species, but varied dramatically with temperature. Both species absorbed between 2.5 and four-times more protein than carbohydrate at low temperatures (8 C and 14 C). At 32 C both species utilized approximately three times more carbohydrate than protein. In spite of reduced consumption at lower temperatures, crayfish absorbed a greater protein portion. At these low temperatures it appears that crayfish maximize the efficiency of protein absorption, presumably for maintenance and growth requirements. At high temperatures it appears that crayfish maximize energy intake, presumably to sustain higher metabolic rates due to increased activity levels. These apparent temperature-dependent nutrient requirements may influence natural foraging strategies or, for species in aquaculture, the effectiveness of commercial feed preparations. At high temperatures P. clarkii was more effective in consuming nutrients than P. zonangulus and may be more successful than P. zonangulus at these temperatures.  相似文献   

HISTOPATHOLOGICAL AIDS TO ROUTINE DIAGNOSIS IN VETERINARY LABORATORIES     

P. S. Watts  Ph.D.  B.Sc.  F.R.C.V.S. 《Australian veterinary journal》1960,36(4):145-148

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Biochemical changes following bilateral nephrectomy in the bovine   总被引：2，自引：0，他引：2  

C Watts  J R Campbell 《Research in veterinary science》1970,11(6):508-514

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GENITAL INFECTIONS OF SHEEP, WITH PARTICULAR REFERENCE TO BRUCELLA-LIKE ORGANISMS     

P. S. Watts  Ph.D.  B.Sc  F.R.C.V.S 《Australian veterinary journal》1955,31(1):1-6

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Immune responses of teleost fish   总被引：6，自引：0，他引：6  

Watts M  Munday BL  Burke CM 《Australian veterinary journal》2001,79(8):570-574

In fish all the pre-requisites to mount a specific immune response are present, but the main differences from the mammalian system are that the secondary response is relatively minor and IgG is not present. In teleosts mainly IgM is present, and IgD has been recently described but its function is, as yet, unknown. However, different forms of fish IgM and its observed flexibility of structure may compensate for a lack of Ig class diversity. The innate immune response of teleosts is highly developed. Multiple forms of key constitutive and inducible components, such as lysozyme, C3, alpha2-macroglobulin and C-reactive protein, are present, and may enhance immune recognition. Low ambient temperature appears to have an impact on all aspects of the immune response, particularly the T-dependent specific immune response due to the non-adaptive lipid composition of T-cell membranes. Temperature effects on the nonspecific immune system are less well characterised, but there is evidence that low temperatures are also suppressive. Knowledge of immune system function becomes essential for disease prevention strategies such as the development of vaccines, selection for increased disease resistance and identification of genes suitable for trangenesis.  相似文献   

Ileal amino acid digestibilities by pigs fed soybean meals from five major soybean-producing countries     

Karr-Lilienthal LK  Merchen NR  Grieshop CM  Flahaven MA  Mahan DC  Fastinger ND  Watts M  Fahey GC 《Journal of animal science》2004,82(11):3198-3209

Growing conditions and processing technologies to which soybeans (SB) are exposed have an effect on digestibilities of AA found in the resultant soybean meals (SBM). This study evaluated SBM from five major SB-producing countries (Argentina, Brazil, China, India, and the United States). An industry representative in each country collected samples of unprocessed SB and SBM subjectively determined to be of high, intermediate, or low quality. The SB from each country were processed into SBM under uniform conditions in the United States. Five experiments (each examining the three SBM and the SB processed in the United States from a single country) were conducted to determine true ileal AAd digestibilities. In addition, a standard SBM purchased on the open market in the United States was used in all experiments as a control. Data from pigs fed a low-protein casein diet in each study were used to calculate true AA digestibilities. Pigs were fitted with simple T-cannulas at the terminal ileum and allotted to treatments in Latin square design experiments. Duplicate experiments were conducted at the University of Illinois and at The Ohio State University. Within each country comparison, pigs fed the SBM processed in the U.S. from SB grown in the five countries had lower (P < 0.05) true total amino acid (TAA) digestibilities than did pigs fed any of the SBM prepared within the country of origin, except the United States. This indicates that processing conditions used at the U.S. pilot plant were not ideal when using SB from other countries. True TAA digestibilities of the diets containing the high-, intermediate-, and low-quality SBM did not differ, except for China, where the low-quality SBM (83.5%) had a lower (P < 0.05) digestibility than the intermediate- (89.6%) or high- (89.0%) quality meals. Soybean meal produced in Argentina (average, 87%) and Brazil (average, 82%) had lower (P < 0.05) true TAA digestibilities than did the standard SBM (91%), indicating that the processing plants in those countries may produce a less digestible SBM than that available on the open market in the United States.  相似文献   

GEOLOGY AT THE BRITISH ASSOCIATION     

Watts WW 《Science (New York, N.Y.)》1897,5(111):252-258

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Organic aerosol formation downwind from the Deepwater Horizon oil spill     

de Gouw JA  Middlebrook AM  Warneke C  Ahmadov R  Atlas EL  Bahreini R  Blake DR  Brock CA  Brioude J  Fahey DW  Fehsenfeld FC  Holloway JS  Le Henaff M  Lueb RA  McKeen SA  Meagher JF  Murphy DM  Paris C  Parrish DD  Perring AE  Pollack IB  Ravishankara AR  Robinson AL  Ryerson TB  Schwarz JP  Spackman JR  Srinivasan A  Watts LA 《Science (New York, N.Y.)》2011,331(6022):1295-1299

A large fraction of atmospheric aerosols are derived from organic compounds with various volatilities. A National Oceanic and Atmospheric Administration (NOAA) WP-3D research aircraft made airborne measurements of the gaseous and aerosol composition of air over the Deepwater Horizon (DWH) oil spill in the Gulf of Mexico that occurred from April to August 2010. A narrow plume of hydrocarbons was observed downwind of DWH that is attributed to the evaporation of fresh oil on the sea surface. A much wider plume with high concentrations of organic aerosol (>25 micrograms per cubic meter) was attributed to the formation of secondary organic aerosol (SOA) from unmeasured, less volatile hydrocarbons that were emitted from a wider area around DWH. These observations provide direct and compelling evidence for the importance of formation of SOA from less volatile hydrocarbons.  相似文献   

The use of remote sensing for estimating ET of irrigated wheat and cotton in Northwest Mexico   总被引：3，自引：0，他引：3  

Jaime Garatuza-Payan  Christopher J. Watts 《Irrigation and Drainage Systems》2005,19(3-4):301-320

Components of a satellite-based system for estimating the crop water requirements of irrigated vegetation have been combined, applied, and tested against field data in the Yaqui Valley, northwest Mexico. Frequent satellite observations have the potential to provide snap shots of cloud variability at the high spatial and temporal resolutions that are needed for making simple, near real-time estimates of incoming solar radiation and, thus, daytime evaporation required for irrigation scheduling. Less frequent polar orbiting satellites offer the capacity of following the vegetation development at higher spatial resolution. The operational framework for obtaining cloud cover has been developed and applied using hourly sampled, 1 km resolution, GOES-10 data received in real-time. The high-resolution, cloud-screening algorithm has proved to be efficient and reliable and has been used to provide high-resolution (4 km) estimates of solar radiation. Relationships between vegetation indices (NDVI and SAVI) and crop coefficients (the ratio of measured to reference evapotranspiration) have been derived with four different models (Shuttleworth, Penman, Priestley–Taylor and Makkink), using ground-based surface reflectance measured over the crop. Continuous measurements of surface fluxes and other meteorological variables were made following almost the entire vegetative cycle of the plant using a station equipped with standard meteorological instruments and an eddy-correlation system. Actual evapotranspiration was computed as the product of the estimated crop coefficients, derived from field radiometer measurements, and reference evapotranspiration. In comparison with ground data, RMSE values are on the order of 1 mm per day. Finally the opportunity to use high-resolution satellite data to make near real-time estimates of crop evaporation is discussed.  相似文献   

Comparative responses of botanical varieties ofBrassica oleracea L. (brussels sprouts,sprouting broccoli and marrow stem kale) to inbreeding and hybridisation     

L. E. Watts 《Euphytica》1970,19(1):78-90

Summary The effects of inbreeding and hybridisation inBrassica oleracea L. were studied in diallel crosses within four varieties of Brussels sprouts three varieties of sprouting broccoli and one kale variety. In addition to each intra-varietal diallel within the two horticultural brassicas, plants of one of the other varieties were also included so that the first diallel analysis could be compared with an intra-plus-intervarietal analysis.In general it was found that the total harvest yield of cultivars of the two horticultural types was controlled by an additive genetic system while whole plant weight of all three brassicas was subject to gene interaction. Selfing for one generation reduced the mean harvest yield of Brussels sprout and sprouting broccoli by 26 and 3%, respectively, compared with their intravarietal F₁'s, while whole plant weight of Brussels sprouts, sprouting broccoli and marrow-stem kale was reduced by 21, 26 and 44%, respectively.Kale plants exhibited significant correlations of plant height with plant yield in 2 years and it is therefore possible to achieve some improvement in yield by selecting for height alone.It was postulated that in kale the greatest yield increases should be obtained by the production of hybrids, but hybridisation with subsequent selection is probably sufficient to increase the yield of the two horticultural brassicas still further.  相似文献