Performance and welfare of Atlantic salmon,Salmo salar L. post-smolts in recirculating aquaculture systems: Importance of salinity and water velocity

Producing a larger post-smolt in recirculating aquaculture systems (RAS) could shorten the production time in sea cages and potentially reduce mortality. Knowledge of the biological requirements of post-smolts in closed-containment systems is however lacking. In the present study, the effects of salinity and water velocity on growth, survival, health, and welfare of Atlantic salmon reared in RAS were examined. Salmon smolts were stocked in three separate RAS with salinities of 12, 22, and 32‰ and subjected to high (1.0 body lengths per s⁻¹) or low (0.3 body lengths second⁻¹) water velocity. Growth performance, survival, welfare, and physiological stress responses were monitored until the fish reached a bodyweight of around 450 g. Growth rate was higher at lower salinity and higher water velocity generally had a positive effect on growth in all salinities. Feed conversion ratio was lower at 12‰ compared to the 22 and 32‰ when the fish were between 250 and 450 g. Higher mortality, elevated plasma cortisol levels, higher incidence of cataract, and a higher expression of stress-induced genes in the skin (iNOS, Muc5ac-like) indicated a negative effect of higher salinity on fish welfare. Male maturation was low (<1%), and not affected by salinity or water velocity.     

Conformational states of sunflower (Helianthus annuus) Helianthinin: effect of heat and pH

The structure and solubility of helianthinin, the most abundant protein of sunflower seeds, was investigated as a function of pH and temperature. Dissociation of the 11S form (hexamer) into the 7S form (trimer) gradually increased with increasing pH from 5.8 to 9.0. High ionic strength (I = 250 mM) stabilizes the 11S form at pH > 7.0. Heating and low pH resulted in dissociation into the monomeric constituents (2-3S). Next, the 7S and 11S forms of helianthinin were isolated and shown to differ in their secondary and tertiary structure, and to have denaturation temperatures (T(d)) of 65 and 90 degrees C, respectively. Furthermore, the existence of two populations of the monomeric form of helianthinin with denaturation temperatures of 65 and 90 degrees C was described. This leads to the hypothesis that helianthinin can adopt two different conformational states: one with T(d) = 65 degrees C and a second with T(d) = 90 degrees C.     

Tentative assignment of the potato serine protease inhibitor group as beta-II proteins based on their spectroscopic characteristics

Potato serine protease inhibitor (PSPI) is the most abundant protease inhibitor group in potato tuber. The investigated PSPI isoforms have a highly similar structure at both the secondary and the tertiary level. From the results described, PSPI is classified as a beta-II protein based on (1) the presence in the near-UV spectra of sharp peaks, indicating a rigid and compact protein; (2) the sharp transition from the native to the unfolded state upon heating (only 6 degrees C) monitored by a circular dichroism signal at 222 nm; and (3) the similarity in secondary structure to soybean trypsin inhibitor, a known beta-II protein, as indicated by a similar far-UV CD spectrum and a similar amide I band in the IR spectrum. The conformation of PSPI was shown also to be stable at ambient temperature in the pH range 4-7.5. Upon lowering the pH to 3.0, some minor changes in the protein core occur, as observed from the increase of the intensity of the phenylalanine peak in the near-UV CD spectrum.     

New device to simulate swallowing and in vivo aroma release in the throat from liquid and semiliquid food systems

This paper describes a novel device to simulate in vivo aroma release from liquids. This artificial throat simulates the act of swallowing followed by exhalation and shows aroma release curves that are similar in shape to in vivo release profiles. Liquids are poured down a tube, and a thin liquid film remains at the inner wall of the tube. Subsequently, aroma compounds release from this film into a stream of air flowing through this tube, which is analyzed by MS-Nose analysis. The effects of air flow rate, contact time with glass surface, presence of saliva, and addition of whey protein, as well as volume, concentration, temperature, and viscosity of the liquid have been studied and compared with aroma release measurements in vivo. A high level of agreement was found. These results confirm the importance of swallowing for aroma release of liquids, as mentioned in the literature, and the usefulness of the new mimicking device.     

GIS在环保型养猪业区域规划中的应用

快速发展的养猪业在带来巨大社会效益和经济效益的同时也带来了许多环境问题，FAO从1998年开始启动了养殖业环境与发展项目，目的是为了在促进养殖业发展、增加经济效益的同时大幅度减少养殖业对环境的不利影响。该文是FAO项目中的一部分，主要是应用GIS技术工具，通过建立养猪业选址的指标体系，发展了可持续的畜牧业生产建设区域规划的决策辅助工具，以减少养猪业发展对环境带来的负面影响；并且将该技术在江西省的养猪大县万年县进行了具体的应用。     

Formation and stability of foam made with various potato protein preparations

In the present study, foam-forming and -stabilizing properties of potato proteins were studied using whipping and sparging tests. The soluble potato proteins are mainly composed of patatin and protease inhibitors. The whipping tests showed that less foam was formed from untreated patatin than from the protease inhibitors, but patatin foam was much more stable. The foam-forming properties of patatin could be strongly improved by partial unfolding of the protein. Whipping tests, at both low (0.5 mg/mL) and high (10 mg/mL) protein concentration, also indicated that foams made with an ethanol-precipitated protein isolate were more stable than those made with beta-casein and beta-lactoglobulin. More generally, it can be concluded that when proteins are used as a foaming agent, a high concentration is required, because the protein available is inefficiently used. Also, there are several variables that may all, in different ways, affect both foam formation (amount of foam, bubbles size distribution) and foam stability. These variables include the type and concentration of protein, solvent conditions (pH, I), and the method used to make the foam.     

Molecular analysis of the Arbuscular mycorrhiza symbiosis

The molecular analysis of the arbuscular mycorrhizal (AM) symbiosis started at the beginning of this decade. The paper summarises the work of the ‘Laboratorium für Molekulare Genetik arbuskulärer Mykorrhiza’ at the MPI für terrestrische Mikrobiologie in Marburg on three major topics. Firstly, the plant response to the mycorrhizal colonisation was analysed using both, targeted and non‐targeted approaches. As an example, the localisation of the gst1 mRNA in potato mycorrhiza is shown. Second, molecular techniques were established to analyse gene expression of the fungal partner of the symbiosis. We present a differential RNA display analysis of spore germination in two AM fungi and the cloning of a gene from Glomus mosseae that shows expression at all stages of the fungal life cycle. In the last part, we introduce the work we are carrying out with a new root endophytic fungus, Piriformospora indica. Infection experiments on maize showed that despite the fungus performs as a root necrotroph, it has a positive effect on plant growth.     

Nitrate leaching in a silage maize field under different irrigation and nitrogen fertilizer rates

Quantification of the interactive effects of nitrogen (N) and water on nitrate (NO₃) loss provides an important insight for more effective N and water management. The goal of this study was to evaluate the effect of different irrigation and nitrogen fertilizer levels on nitrate-nitrogen (NO₃-N) leaching in a silage maize field. The experiment included four irrigation levels (0.7, 0.85, 1.0, and 1.13 of soil moisture depletion, SMD) and three N fertilization levels (0, 142, and 189 kg N ha⁻¹), with three replications. Ceramic suction cups were used to extract soil solution at 30 and 60 cm soil depths for all 36 experimental plots. Soil NO₃-N content of 0-30 and 30-60-cm layers were evaluated at planting and harvest maturity. Total N uptake (NU) by the crop was also determined. Maximum NO₃-N leaching out of the 60-cm soil layer was 8.43 kg N ha⁻¹, for the 142 kg N ha⁻¹ and over irrigation (1.13 SMD) treatment. The minimum and maximum seasonal average NO₃ concentration at the 60 cm depth was 46 and 138 mg l⁻¹, respectively. Based on our findings, it is possible to control NO₃ leaching out of the root zone during the growing season with a proper combination of irrigation and fertilizer management.     

Retinoic acid signaling restricts the cardiac progenitor pool

Organogenesis begins with specification of a progenitor cell population, the size of which provides a foundation for the organ's final dimensions. Here, we present a new mechanism for regulating the number of progenitor cells by limiting their density within a competent region. We demonstrate that retinoic acid signaling restricts cardiac specification in the zebrafish embryo. Reduction of retinoic acid signaling causes formation of an excess of cardiomyocytes, via fate transformations that increase cardiac progenitor density within a multipotential zone. Thus, retinoic acid signaling creates a balance between cardiac and noncardiac identities, thereby refining the dimensions of the cardiac progenitor pool.     

Spatial and temporal genetic variation of Drosophila suzukii in Germany

Native to Southeast Asia, the spotted wing drosophila (SWD), Drosophila suzukii Matsumura, rapidly invaded America and Europe in the past 20 years. As a crop pest of soft-skinned fruits with a wide range of host plants, it threatens the fruit industry worldwide, causing enormous economic losses. To control this invasive pest species, an understanding of its population dynamics and structure is necessary. Here, we report the population genetics and development of SWD in Germany from 2017–19 using microsatellite markers over 11 different sample sites. It is the first study that examines SWD’s genetic changes over 3 years compared to multiple international SWD laboratory strains. Results show that SWD populations in Germany are highly homogenous without differences between populations or years, which indicates that populations are well adapted, migrate freely, and multiple invasions from outside Germany either did not take place or are negligible. Such high genetic variability and migration between populations could allow for a fast establishment of the pest species. This is especially problematic with regard to the ongoing spread of this invasive species and could bear a potential for developing pesticide resistance, which could increase the impact of the SWD further in the future.