基于不同回收方法的肌浆蛋白对鲢鱼糜冻融稳定性的影响

为研究不同回收方法的肌浆蛋白对鲢鱼糜冻融稳定性的影响,分别通过加热法、酸偏移法和酸偏移-耦合壳聚糖絮凝法回收鲢鱼糜漂洗液中的肌浆蛋白,并将其添加至鱼糜中,测定鱼糜冻融循环过程中蛋白质冷冻变性、脂肪氧化及凝胶品质的指标。结果显示:添加不同方法回收的肌浆蛋白均能抑制鲢鱼糜冻融循环过程中盐溶性蛋白含量、Ca²⁺-ATPase活性和总巯基含量的下降以及表面疏水性的上升,其中加热法回收的肌浆蛋白抑制鱼糜蛋白质冷冻变性的效果最显著,经过9次冻融后仍能够对鱼糜蛋白质变性起到抑制效果。蛋白质羰基含量测定结果显示,肌浆蛋白的添加可以抑制鱼糜冻融循环过程中蛋白质氧化现象。而与空白组鱼糜相比,添加不同回收处理的肌浆蛋白的鱼糜,其硫代巴比妥酸值（TBARs）和pH值并没有显著变化。此外,随着冻融循环次数的增加,鱼糜凝胶品质会发生严重劣化,其中添加酸偏移-耦合壳聚糖絮凝处理的肌浆蛋白的鱼糜始终保持较好的凝胶质构性能。     

Stocking effectiveness of hatchery-released kuruma prawns estimated by two-stage sampling of commercial catch in Ariake Sound, Japan

ABSTRACT:    To evaluate the stocking effectiveness of the kuruma prawn Penaeus japonicus , a two-stage sampling survey of Gensiki bottom-drift-netters was carried out in Ariake Sound, Saga Prefecture, Japan. A total of 471 000 hatchery-produced juveniles, marked by cutting off the right uropods, was released. Thirty-three fishing days were randomly drawn from four boats, which were selected from the 80 boats operating in the fishery. All prawns caught on the selected days were examined, and the hatchery-produced individuals were identified by their regenerated uropods. A telephone survey of all boats was also conducted, to determine the number of fishing days. A total of 286 marked prawns were caught on the survey days for the Saga area in Ariake Sound, from the last half of July to the first half of September 2002. The recapture rate and standard error were estimated at 0.76 ± 0.52%. Economic efficiency was estimated at 0.28 ± 0.02. Strategies for sampling schemes and stock recovery are also discussed.     

Turnover of Se in adequately fed chickens using Se‐75 as a tracer

Inorganic selenium (Se) in the form of selenite is applied to livestock to avoid Se deficiency. Selenite is, however, an artificial Se source in diets of unsupplemented chickens. It is therefore hypothesized that organic Se sources, such as Se‐enriched yeast and wheat, could be a more suitable Se supply in animal nutrition, although information on the transition of Se from organic Se sources in fast‐growing chickens is scarce. In this work, chickens were fed a low Se diet (0.27 ± 0.01 mg Se/kg, Se‐enriched yeast) until 20 days of age, after which the Se concentration was increased to maximum concentration allowed by the poultry industry in Europe (0.5 p.p.m. Se). At the same time, a daily contribution of carrier‐free ⁷⁵Se tracer from labelled wheat was administered from day 20 to 27. The chickens showed S and Se homeostasis, as the concentration of S and Se in liver, blood or kidney remained about constant, and steady state of S and Se in the other organs was reached 1 day after the diet shift. The uptake of ⁷⁵Se was readily seen in all organs. After 1 week, the depuration of the ⁷⁵Se tracer was followed, and biological half‐lives and retention in individual organs were determined. The shortest biological half‐lives were observed in major metabolic organs, the liver, kidney and pancreas with half‐lives close to 4 days. There was a significant (p < 0.05) uptake in lung, brain and muscle that reached steady state when the administration of ⁷⁵Se was terminated. The half‐life of ⁷⁵Se in heart was 9 days and 7 days in blood. The longest half‐lives were observed in muscle (12 days), brain and lungs (13 days). All half‐lives were shorter than in Se deplete animals.     

Evaluation of different approaches to individual tree growth and survival modelling using data collected at irregular intervals - a case study for Pinus patula in Kenya

Background： The minimum set of sub-models for simulating stand dynamics on an individual-tree basis consists of tree-level models for diameter increment and survival. Ingrowth model is a necessary third component in uneven-aged management. The development of this type of model set needs data from permanent plots, in which all trees have been numbered and measured at regular intervals for diameter and survival. New trees passing the ingrowth limit should also be numbered and measured. Unfortunately, few datasets meet all these requirements. The trees may not have numbers or the length of the measurement interval varies. Ingrowth trees may not have been measured, or the number tags may have disappeared causing errors in tree identification. Methods： This article discussed and demonstrated the use of an optimization-based approach to individual-tree growth modelling, which makes it possible to utilize data sets having one or several of the above deficiencies. The idea is to estimate all parameters of the sub-models of a growth simulator simultaneously in such a way that, when simulation begins from the diameter distribution at the first measurement occasion, it yields a similar ending diameter distribution as measured in the second measurement occasion. The method was applied to Pinus patula permanent sample plot data from Kenya. In this dataset, trees were correctly numbered and identified but measurement interval varied from 1 to 13 years. Two simple regression approaches were used and compared to the optimization-based model recovery approach. Results： The optimization-based approach resulted in far more accurate simulations of stand basal area and number of surviving trees than the equations fitted through regression analysis. Conclusions： The optimization-based modelling approach can be recommended for growth modelling when the modelling data have been collected at irregular measurement intervals.     

垄茶高速公路边坡生态恢复中先锋植物的选择研究

指出了高速公路的建设对环境具有较强的破坏作用,不仅影响景观,还影响植被的生长。为了能尽快恢复植被的生长,对高速公路边坡生态恢复中先锋树种的选择进行了研究。阐述了边坡绿化的功能,提出了高速公路边坡先锋植物的选择原则和习性要求,分析了垄茶高速公路边坡的环境特点,并探讨了其边坡绿化的有效措施,特别是就先锋树种选择、植物的文化内涵和植物配置等方面进行了研究。提出了应用植物35种,其中包括豆科、蔷薇科、杜鹃花科、胡颓子科、桦木科、鼠李科等。其结果对国内高速公路边坡植被恢复具有较强的参考价值。     

A new large‐scale and cost‐effective restoration method for cold‐water coral gardens

1. Gorgonians dwelling on the Mediterranean continental shelf are among the most frequent fishing bycatch taxa. These species display several traits, such as long lifespans and slow growth, which make them very vulnerable to the impacts caused by fishing activities with far‐reaching and long‐lasting effects.
2. Hence, restoration and mitigation actions are crucial to enhance and speed up the natural recovery of damaged cold‐water coral gardens. Given the growing concern to develop effective and affordable restoration actions, the present study aims to propose and technically validate a new large‐scale and cost‐effective restoration method.
3. This technique, named ‘badminton method', consists of attaching bycatch Eunicella cavolini colonies to cobble supports and returning them to the continental shelf by gently throwing the gorgonian transplants directly from a boat.
4. Two consecutive field experiments were conducted in order to find the best cobble type support and gorgonian size to be used: first, to evaluate the landing efficiency of gorgonian transplants at different depths (from 5 to 30 m) and second, to evaluate their capability to maintain a correct position over time.
5. Natural cobbles with large gorgonians attached were the best option. Field results and modelling approaches suggest that the transplants would correctly land on the continental shelf seabed in a predicted area of around 60 m². Moreover, they would successfully maintain an upright position ensuring gorgonian survival over time.
6. The success of this method highlights the feasibility of large‐scale and low‐cost restoration actions with promising results for the conservation and recovery of cold‐water coral gardens.

     

Environmental and physiological conditions affecting Tetrahymena sp. infection in guppies, Poecilia reticulata Peters

Parasitic infections caused by Tetrahymena sp. constitute a serious problem in guppies, Poecilia reticulata. Tetrahymena was isolated from skin lesions of naturally infected guppies in a commercial aquaculture farm, cultured in vitro and used in subsequent experimental infections. In addition to guppies, angelfish, Pterophyllum scalare, platyfish, Xiphophorus maculates, and neontetra, Paracheirodon innesi, were susceptible, whereas tilapia (Oreochromis niloticus xO. aureus) was resistant. The ciliate had a high affinity for dead fish. Skin abrasion did not affect the infection, but fish with gas bubble disease exhibited a significantly higher infection than non-affected fish. Infection was significantly higher when fish were exposed to high levels of ammonia, high organic load and low water temperatures. Under shipment conditions, infection was significantly elevated. Full recovery was achieved at a low fish density. Results suggest that poor environmental and physiological conditions enhance infection with Tetrahymena sp.     

Stewardship as a Path to Cooperation? Exploring the Role of Identity in Intergroup Conflict Among Michigan Wolf Stakeholders

Post-recovery wolf management remains controversial. In Michigan, dialogue centers on hunting wolves but controversy may be more nuanced than simple pro- or anti-hunting positions. Social identity may cause stakeholders to organize in groups and identity differences may be driving controversy. To explore stakeholder disagreement over wolf management, we conducted semi-structured key informant interviews (n = 21) about identity and stewardship in August–September 2012. Four overarching identity themes emerged regarding: (a) management objectives, (b) focal levels, (c) control methods, and (d) justifications for methods. Themes indicated two main researcher-defined identity groups. Interviewees from both groups identified six common stewardship themes: (a) bequest values, (b) ecosystem health, (c) education, (d) existence values, (e) pride in natural resources, and (f) sustainability. Findings suggest stakeholders may be conflicting over opposing identities vis-à-vis organization affiliation, which may be related to what management strategies individuals oppose. Establishing common stewardship objectives through established participation methods may help alleviate controversy.     

Renibacterium salmoninarum bar forms: characterization, occurrence, and evidence of a host response to a R. salmoninarum infection

Unique-staining Renibacterium salmoninarum (Rs) cells, termed bar forms, first observed in a coho salmon, Oncorhynchus kisutch (Walbaum), in 1983, could not be cultured, making their characterization difficult and significance obscure. They can be detected only by the fluorescent-antibody technique (FAT) and their numbers estimated only by a quantitative FAT (QFAT). Data collected over a 10-year period showed that bar forms were observed only in vivo and appeared associated with a host response. Bar forms were observed in 10 salmonid species from five countries and in fish from < 1 g to spawning adults. They were observed in 50.1% of kidney smears prepared from 10,061 Rs positive chinook, O. tshawytscha (Walbaum), coho, and Atlantic salmon, Salmo salar L. Bar forms were shown to be Rs cells based on absorption studies, their reaction with an Rs-specific FAT and enzyme-linked immunosorbent assay, and a transition from 'typical' Rs cells to bar forms in naturally and experimentally infected fish. Bar forms were determined to be non-virulent, damaged or dead Rs cells, based on fluorescence and electron microscopy observations, the inability to culture them, and mortality data. Bar forms appeared to represent visual markers of recovery from an Rs infection.     

Digestibility, faeces recovery, and related carbon, nitrogen and phosphorus balances of five feed ingredients evaluated as fishmeal alternatives in Nile tilapia, Oreochromis niloticus L.

This study shows that alternatives for fishmeal in a fish diet affect not only fish growth but also faeces stability and nitrogen (N) and phosphorus (P) waste production. Wheat gluten diet (WGD), soybean meal extract diet (SBE), soybean meal diet (SBM), duckweed diet (DWD) and single‐cell protein diet (SCP) were evaluated as a fishmeal replacement on a 15% weight weight^?1 basis in tilapia diets. Fishmeal replacement affected dry matter (dm), protein, ash and P digestibility significantly. Faeces recovery (6.8–11.2%) was not significantly affected, although the amount of non‐recovered faeces and total faeces showed significant differences. Duckweed diet and SCP resulted in the largest amounts of non‐recovered and total faeces (199–210, 224–225 g dm kg^?1 feed dm). Compared with fishmeal diet (FMD), the WGD and SBE resulted in similar growth, but higher non‐faecal N losses (471–495 vs. 416 g N kg^?1 N). Soybean meal diet, DWD and SCP resulted in lower growth but less non‐faecal loss (409–450 g N kg^?1 N). The DWD and FMD had the highest N retention (480 g N kg^?1 N) compared with the other diets (431–451 g N kg^?1 N). Carbon retention, faecal and non‐faecal losses and P retention were similar for all diets (302–358, 142–176 and 489–523g C kg^?1 C, 606–704 g P kg^?1 P). Phosphorus faecal loss was lower for all diets (329–381 g P kg^?1 P) than for the FMD (401 g P kg^?1 P).