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The present study investigated nutritional programming in Atlantic salmon to improve utilisation of a vegetable-based diet. At first exogenous feeding, fry were fed either a marine-based diet (Diet Mstimulus, 80% fishmeal (FM)/4% fish oil (FO)) or a vegetable-based diet (Diet Vstimulus, 10% FM/0% FO) for 3 weeks. Subsequently, all fish were then fed under the same conditions with a commercial, marine-based, diet for 15 weeks and thereafter challenged with a second V diet (Diet Vchallenge, 10% FM/0% FO) for 6 weeks. Diploid and triploid siblings were run in parallel to examine ploidy effects. Growth performance, feed intake, nutrient utilisation and intestinal morphology were monitored. Fish initially given Diet Vstimulus (V-fish) showed 24 % higher growth rate and 23 % better feed efficiency compared with M-fish when later challenged with Diet Vchallenge. There was no difference in feed intake between nutritional histories, but increased nutrient retentions highlighted the improved utilisation of a V diet in V-fish. There were generally few significant effects of nutritional history or ploidy on enteritis scores in the distal intestine after the challenge phase as only V-triploids showed a significant increase (P<0·05) in total score. The data highlighted that the positive effects were most likely a result of nutritional programming and the ability to respond better when challenged later in life may be attributed to physiological and/or metabolic changes induced by the stimulus. This novel study showed the potential of nutritional programming to improve the use of plant raw material ingredients in feeds for Atlantic salmon.
Bandelier National Monument (BNM) was created to protect an extraordinary inventory of archaeological resources carved in the Tshirege Member of the Bandelier Tuff. These include more than one thousand excavated chambers, called cavates, used for dwelling, storage, and textile production. The glass-rich tuffs at the base of the Tshirege Member are poorly consolidated and susceptible to erosion by wind, rain, and mechanical abrasion, with resultant loss of cultural material. However, rock surfaces develop protective weathering rinds that are resistant to erosion. Using optical microscopy, SEM-EDS, XRD, and electron microprobe analysis, we determined that this rind consists of clay and silt sediments colonized by lichens and other surface biota, accompanied by the precipitation of secondary minerals in the near-surface pore space. Scoping experiments focused on glass-organic acid interactions indicate that oxalic acid excreted by microbial crust constituents catalyzes biogeochemical reactions that lead to the preferential dissolution of Si, Al, and Fe components of the volcanic glass; these cations become available for precipitation of opal, and smectite and sepiolite clays. Enzyme assays that quantify biological activity at outcrop surfaces indicate that microbial populations initially thrive as they derive nutrients from the dissolution reactions of the glass, but activity starts to decline as precipitation of secondary minerals limits access to new sources of nutrients, so that alteration processes are self-limiting. As case hardening progresses, imbibition rates at the surface decrease, and the erosion resistance of the altered surfaces is substantially improved. This article presents summary results of research conducted over a period of five years to characterize the roles of lichens and other microflora in rind formation, and the resulting contributions to tuff stability. The interaction of lichens and other microflora with rock surfaces in archaeological sites and monuments is usually explored in terms of biodeterioration and consequent damage. However, this study shows that, under some circumstances, lichens and microflora provide a level of erosion protection to relatively porous and unconsolidated rock strata that outweighs their biodeteriorative effects.
A HST-wfpc2 survey of Galactic Wolf-Rayet stars was undertaken over a five year period, in an effort to discover new close visual companions, tight clusters, and/or association memberships. In total, 61 Galactic WR stars were observed, with nine objects being members of the subclasses WC8 and WC9, which are associated with dust production. For these nine, we present images of WR 11, WR 48a, WR 69, WR 70, WR 81, and WR 92. We refer to Wallace et al. (2002) for discussion of WR 98a, WR 104, and WR 112. Overall, we find for separations of approximately ≥ 150 mas, that the binary/association properties of the WC8/WC9 sample are statistically indistinguishable from the overall WR population. These statistics are limited, however, by the small numbers of each WR subclass observed.
We have observed planetary nebulae (PNe) in several early-type galaxies using new techniques on 4- to 8-meter-class telescopes. We obtain the first large data sets (≳ 100 velocities each) of PN kinematics in galaxies at ≳ 15 Mpc, and present some preliminary dynamical results.
We compare reactions in the prices and trading patterns of common stocks and closed-end funds (CEFs), securities with substantially different investor clienteles, to the Sept. 11, 2001 terrorist attacks. When the market reopened 6 days later, retail investors sold and there were sharp price declines, even in assets with net institutional buying. In the subsequent 2 weeks, price reversals were substantially security specific and thus not simply due to improved systematic sentiment. Consistent with microstructure theory, comparisons between CEFs and common stocks show the speed of these reversals depended significantly on the relative quality and availability of information about fundamental values.
Most studies on dietary vegetable oil in rainbow trout (Oncorhynchus mykiss) have been conducted on a background of dietary EPA (20 : 5n-3) and DHA (22 : 6n-3) contained in the fishmeal used as a protein source in aquaculture feed. If dietary EPA and DHA repress their endogenous synthesis from α-linolenic acid (ALA, 18 : 3n-3), then the potential of ALA-containing vegetable oils to maintain tissue EPA and DHA has been underestimated. We examined the effect of individual dietary n-3 PUFA on the expression of the biosynthetic genes required for metabolism of ALA to DHA in rainbow trout. A total of 720 juvenile rainbow trout were allocated to twenty-four experimental tanks and assigned one of eight diets. The effect of dietary ALA, EPA or DHA, in isolation or in combination, on hepatic expression of fatty acyl desaturase (FADS)2a(Δ6), FADS2b(Δ5), elongation of very long-chain fatty acid (ELOVL)5 and ELOVL2 was examined after 3 weeks of dietary intervention. The effect of these diets on liver and muscle phospholipid PUFA composition was also examined. The expression levels of FADS2a(Δ6), ELOVL5 and ELOVL2 were highest when diets were high in ALA, with no added EPA or DHA. Under these conditions ALA was readily converted to tissue DHA. Dietary DHA had the largest and most consistent effect in down-regulating the gene expression of all four genes. The ELOVL5 expression was the least responsive of the four genes to dietary n-3 PUFA changes. These findings should be considered when optimising aquaculture feeds containing vegetable oils and/or fish oil or fishmeal to achieve maximum DHA synthesis.
Previous studies of live-collected pre-weapons testing mollusk shells in the northern Gulf of California have demonstrated that the local radiocarbon reservoir effect (ΔR) is large and highly variable. To test the validity of this observation for paired charcoal and shell samples from archaeological contexts, we dated samples from four shell midden locations and six midden layers from the eastern shoreline of the Gulf of California near Puerto Peñasco, Sonora, Mexico. Dated charcoal samples were small twigs or brushy plants used to cook shellfish and the shells dated within each midden showed signs of burning. Ages range from approximately 5700 to 1900 cal BP. The offset between the modeled marine 14C age for calibrated ages of the middens and measured shell 14C age (ΔR) averaged 425 yr with a standard deviation of 115 yr.