Thermal shock induction of triploidy in Atlantic cod (Gadus morhua L.)

The effects of thermal treatments on induction of triploidy in Atlantic cod have been investigated. Cold shock [−1.7±0.1°C at 20 min post fertilization (PF) for 2 h] was based on a previously developed protocol, and heat shocks, below the lethal threshold of 24°C, were at 16, 18 or 20°C applied 20, 30 or 40 min PF for 20 min. Cold shock did not affect larval survival and was ineffective for producing triploids (range 0–4%). A heat shock of 20°C at 20 min PF generated the highest percentages (range 66–100%) of triploid larvae at hatching, with survival ranging from 10% to 20% relative to the controls. Lower heat shock temperatures or delayed shocks increased survival but decreased the number of triploids, providing no net gain in triploid yield (range 1–9%). Heat shocks applied later than 20 min PF produced 2–4% tetraploid larvae at hatching. A thermal shock of 20°C initiated at 20 min PF and lasting 20 min proved to be the most generally efficient treatment for induction of triploidy in Atlantic cod.     

Simulation of Short-Term Management Actions to Prevent Oxygen Depletion in Ponds

This study examined possible changes in dissolved oxygen concentration resulting from various short-term management actions that can be undertaken in response to cloudy conditions. The management actions were examined with a computer model of water quality in a pond, and include nutrient enrichment (fertilization, pH adjustment), water level control, and water exchange. Results of these simulations indicated that general management strategies directed at increasing nutrient availability were the least effective in counteracting the effect of the increased cloud cover. Flushing and reducing the water level in the pond were considerably more effective short-term management actions. Areas for field research were suggested to confirm the effectiveness of the various strategies.     

Culling prey promotes predator recovery--alternative states in a whole-lake experiment

Many top-predator fish stocks in both freshwater and marine systems have collapsed as a result of overharvesting. Consequently, some of these communities have shifted into seemingly irreversible new states. We showed, for predators feeding on prey that exhibit food-dependent growth, that culling of fish prey may promote predator recovery. We removed old stunted individuals of a prey-fish species in a large, low-productive lake, which caused an increase in the availability of small-sized prey and allowed the predator to recover. The shift in community state has been sustained for more than 15 years after the cull ended and represents an experimental demonstration of an alternative stable state in a large-scale field system. Because most animals exhibit food-dependent growth, shifts into alternative stable states resulting from overcompensating prey growth may be common in nature and may require counterintuitive management strategies.     

Fingerprints for main varieties of argentinean wines: terroir differentiation by inorganic, organic, and stable isotopic analyses coupled to chemometrics

Our main goal was to investigate if robust chemical fingerprints could be developed for three Argentinean red wines based on organic, inorganic, and isotopic patterns, in relation to the regional soil composition. Soils and wines from three regions (Mendoza, San Juan, and Co?rdoba) and three varieties (Cabernet Sauvignon, Malbec, and Syrah) were collected. The phenolic profile was determined by HPLC-MS/MS and multielemental composition by ICP-MS; (87)Sr/(86)Sr and δ(13)C were determined by TIMS and IRMS, respectively. Chemometrics allowed robust differentiation between regions, wine varieties, and the same variety from different regions. Among phenolic compounds, resveratrol concentration was the most useful marker for wine differentiation, whereas Mg, K/Rb, Ca/Sr, and (87)Sr/(86)Sr were the main inorganic and isotopic parameters selected. Generalized Procrustes analysis (GPA) using two studied matrices (wine and soil) shows consensus between them and clear differences between studied areas. Finally, we applied a canonical correlation analysis, demonstrating significant correlation (r = 0.99; p < 0.001) between soil and wine composition. To our knowledge this is the first report combining independent variables, constructing a fingerprint including elemental composition, isotopic, and polyphenol patterns to differentiate wines, matching part of this fingerprint with the soil provenance.     

A review of wood thermal pretreatments to improve wood composite properties

The objective of this paper is to review the published literature on improving properties of wood composites through thermal pretreatment of wood. Thermal pretreatment has been conducted in moist environments using hot water or steam at temperatures up to 180 and 230 °C, respectively, or in dry environments using inert gases at temperatures up to 240 °C. In these conditions, hemicelluloses are removed, crystallinity index of cellulose is increased, and cellulose degree of polymerization is reduced, while lignin is not considerably affected. Thermally modified wood has been used to manufacture wood–plastic composites, particleboard, oriented strand board, binderless panels, fiberboard, waferboard, and flakeboard. Thermal pretreatment considerably reduced water absorption and thickness swelling of wood composites, which has been attributed mainly to the removal of hemicelluloses. Mechanical properties have been increased or sometimes reduced, depending on the product and the conditions of the pretreatment. Thermal pretreatment has also shown to improve the resistance of composites to decay.     

Accuracy of an indirect fluorescent-antibody test and of a complement-fixation test for the diagnosis of Babesia caballi in field samples from horses

We evaluated the indirect fluorescent-antibody (IFA) test and complement-fixation (CF) test for diagnosis of equine piroplasmosis in the absence of a gold standard. Using Evan's blue, we estimated the specificity of the IFA test on a parasite-free, field horse population to be 98% (95% confidence interval=97, 99). We observed an excellent test agreement (kappa=0.83) between two collaborating laboratories when the IFA test was performed on identical samples from an endemic area. Using Bayesian analysis with informative prior probability distributions, we estimated the sensitivity of the IFA test to be 92% (95% probability interval, PI=81, 98), and specificity to be 95% (95% PI=88, 99). The CF test sensitivity and specificity estimates were 28% (95% PI=15, 47) and 99% (95% PI=96, 100), respectively. We found the IFA to be superior to the CF test, and the inclusion of Evan's blue in test protocol improved the performance of the IFA test. We conclude that the IFA test for Babesia caballi is a sensitive and specific test for the diagnosis of equine piroplasmosis.     

Cellular activity and development of enteric,hepatic and muscle tissues of juvenile pacu Piaractus mesopotamicus (Holmberg 1887) fed with lyophilized bovine colostrum

Bovine colostrum, an alternative food of animal origin provided as partial protein source, may constitute an innovative ingredient in fish feeding. Serum insulin‐like growth factor 1 (IGF‐1) and cellular activity of enteric, hepatic and muscle tissues of juvenile pacu Piaractus mesopotamicus fed with lyophilized bovine colostrum (LBC) were evaluated. Pacu (8.46 ± 0.74 g; 7.75 ± 0.27 cm, n = 18 in triplicate) were stocked into 18 tanks (300 L; 18 fish per tank, in triplicate) and fed with control diet containing 0% of LBC or experimental diet containing 10% and 20% of LBC inclusion for either 30 or 60 days of experiment. IGF‐1 serum concentration was not affected (P > 0.05) by the diet containing LBC and experimental period. The intestinal and hepatic cellular activity was not influenced by LBC (P > 0.05); however, intestine protein/RNA decreased at 60 days (P < 0.05). The muscle cellular activity was affected by LBC, highest in fish fed with diet containing 10% of LBC (P < 0.05). Between the periods DNA and protein/RNA increased at 60 days, while RNA, protein/DNA and RNA/DNA ratio decreased in this same period (P < 0.05). Increased DNA muscle content indicates fish growth by hyperplasia. The results of the present study is related with suitable development of enteric, hepatic and muscle tissues and proper condition of juvenile pacu fed with LBC considering the absence of differences in relation to juveniles that consumed diet without colostrum.