木瓜蛋白酶凝固大豆蛋白质机理

本文研究了木瓜蛋白酶对豆浆的凝固机理，通过酶反应过程中游离氨基和蛋白质表面疏水性的变化，初步确定酶法凝固的机理是在酶的作用下，蛋白质暴露了一些疏水基,并立即通过蛋白质分子间的疏水相互作用结合成凝胶。     

Qualitative risk assessment of routes of transmission of the exotic fish parasite Gyrodactylus salaris between river catchments in England and Wales

Gyrodactylus salaris is a freshwater, monogenean ecto-parasite of Atlantic-salmon. Infection of its natural host, the Baltic strain of Atlantic-salmon, is inapparent. G. salaris also can infect rainbow-trout (Oncorhynchus mykiss) permanently, and cause infection of ≤50 days in several other species. It is only on Atlantic stocks of Atlantic-salmon (Salmo salar) that the parasite multiplies unchecked by an immune response, causes death in juveniles and dramatic reductions in wild populations. In Norway, the parasite has been introduced into 45 rivers, resulting in reductions in Atlantic-salmon stocks of up to 98%. It is probably the most-important exotic fish-disease threat to the UK. We used risk analysis to assess the most-important routes of spread for G. salaris between rivers in England and Wales. The movement of live rainbow-trout was identified as the most-important route of transmission; this route is likely to lead rapidly to the wide geographic spread of the parasite. The movement of other species of fish (especially from sites holding rainbow-trout) is also an important risk. Other routes of spread (including mechanical transmission on farm equipment and vehicles, angling equipment, canoes, etc.) might allow limited local spread (mainly to neighbouring rivers).     

热处理对鱼肉品质的影响研究进展

热处理是传统的加工方法,对食品加工具有重要的意义。比较了热处理对不同鱼肉肌肉蛋白质即肌原纤维蛋白、肌浆蛋白及肌基质蛋白的表面疏水性、表面活性巯基的影响,并对脂质因热处理产生的氧化、组分变化以及热处理对鱼肉颜色、硬度等品质的影响进行综述。     

传统时代南海九江的鱼苗养殖业与桑基鱼塘

南海九江地区的桑基鱼塘是珠三角基塘农业经营历史最悠久、技术最成熟的区域。清代初年这里的鱼苗养殖已经十分兴盛,已经形成连片的桑基鱼塘。九江位于西江下游,这里的居民长期垄断了西江的鱼苗捕捞和养殖技术。鱼苗养殖是九江地基塘农业经营的重要组成部分,鱼苗养殖的特定技术也促使当地基塘形成了多样化的形态与特定的微环境特征。基塘属于小型的水利工程,九江地区桑基鱼塘与堤围的修建,塑造出适应基塘排灌需要的人工河网。九江地区桑基鱼塘是典型的循环农业,经营中的施行立体化的种养殖模式。     

Effects of different fermented soy protein and apparent ileal digestible lysine levels on weaning pigs fed fermented soy protein‐amended diets

Two experiments were conducted to evaluate the effect of different fermented soybean proteins and the apparent ileal digestible lysine levels on weaning pigs fed fermented soy protein (FSP)‐amended diets. In Exp. 1, 70 crossed piglets (6.25 ± 0.40 kg) were used in a 5‐week trial to evaluate two different FSP. In Exp. 2, 20 weaning barrows (6.15 ± 0.45 kg) were used in a metabolism trial to determine the effects of the apparent ileal digestible (1.2, 1.3, 1.4 and 1.5%) lysine levels in weaning pigs fed FSP (5%) diet. In Exp. 1, pigs fed the diet containing Lactobacillus spp. FSP showed higher nitrogen (N) digestibility (P < 0.05), lower blood urea nitrogen and serum creatinine levels (P < 0.05) than those fed the Aspergillus oryzae FSP diet. In Exp. 2, increasing dietary lysine levels increased the average daily gain, apparent dry matter, N digestibility, N retention and essential amino acids in the current study (P < 0.05), with the 1.5% showing the highest value. In conclusion, pigs fed Lactobacillus spp. FSP had a higher N digestibility than those fed A. oryzae FSP. The optimal apparent ileal digestibility lysine level in fermented soy protein diets (3550 kcal/kg metabolizable energy) for maximizing growth performance and N utilization in the first 7 days (6.25 kg) was 1.5%.     

Effects of open- and closed-system temperature changes on blood O2-binding characteristics of Atlantic bluefin tuna (Thunnus thynnus)

We investigated the effects of open- and closed-system temperature changes on the O₂ affinity of Atlantic bluefin tuna (Thunnus thynnus) blood using in vitro methods essentially identical to those previously employed on tropical tuna species. Bluefin tuna blood has a general O₂ affinity (P ₅₀ = 2.6–3.1 kPa or 19–23 mm Hg at 0.5% CO₂) similar to that of skipjack tuna, yellowfin tuna, and kawakawa blood (P ₅₀ = 2.8–3.1 kPa at 0.5% CO₂) but significantly above that of bigeye tuna blood (P ₅₀ = 1.6–2.0 kPa at 0.5% CO₂). We therefore hypothesize that bluefin tuna are less tolerant of hypoxia than bigeye tuna. Further, we found the P ₅₀ of bluefin tuna blood to be slightly reduced by a 10°C open-system temperature increase (e.g., from 4.83 kPa at 15°C to 3.95 kPa at 25°C) and to be completely unaffected by a 10°C closed-system temperature change. Bluefin tuna blood, therefore, had a significantly reduced Bohr effect when subjected to the inevitable changes in P CO ₂ and plasma pH that accompany closed-system temperature shifts (0.04–0.09 Δlog P₅₀ΔpH⁻¹) compared with the effects of changes in plasma pH accomplished by changing P CO ₂ alone (0.81–0.94 Δlog P₅₀ Δ pH⁻¹). This response is similar to that of skipjack tuna blood, but different from yellowfin or bigeye tuna blood. During closed-system temperature changes at oxygen levels above P ₅₀, however, bluefin tuna blood showed a reversed temperature effect (i.e., P O ₂ decreased in response to an increase in temperature). Unlike in other tuna species, temperature effects on O₂ affinity of bluefin tuna whole blood were similar to those previously reported for hemoglobin solutions, suggesting that red cell-mediated ligand changes are not involved.     

Collie eye anomaly in Collies in the Netherlands

Summary

The eyes of 160 Collies were examined for Collie Eye Anomaly, Progressive Retinal Atrophy, and any other eye abnormality present. The incidence of CEA in 160 Collies was 40.6 per cent.

There were no cases of PRA. Other abnormalities noted were distichiasis, persistent pupillary membranes, distinct remnants of the hyaloid artery, corneal dystrophy and unilateral cataracts.     

鱼体重金属检测方法的研究进展

工业的快速发展使包括重金属在内的大量污染物进入水体,从而导致水生生态系统遭受不同程度的破坏,并加剧了水产品的重金属污染。因此,对水产品重金属检测方法的研究迫在眉睫。介绍了鱼类重金属离子检测技术,并讨论了现存重金属检测技术的优缺点和未来的发展方向,以期为筛选或研制出灵敏度更高、准确度更好、速度更快的检测方法提供依据。     

江苏里下河地区鸭鱼共养模式研究

[目的]探讨江苏里下河地区半放养情况下鸭鱼共生比例关系。[方法]通过鸭鱼共养试验测定鸭日排粪量和鱼塘中鸭粪的施肥量,并观测正常养鸭情况下河塘水质情况和鱼的生长情况。[结果]每只鸭每天排出153g新鲜粪。鸭粪中干物质含量为44．83％,全氮含量为1．67％,全磷含量为0．92％,全钾含量为1．62％。采用鸭鱼共养模式可以提高江苏里下河地区养殖的综合效益。[结论]鸭鱼共养模式在江苏里下河地区具有较高的推广价值。     

大豆蛋白对麦芯粉流变学特性的影响研究

将大豆蛋白粉和麦芯粉以不同比例混合配制复合粉,利用粉质仪和拉伸仪对复合粉流变学特性指标进行测试,研究大豆蛋白对麦芯粉的影响及其规律。结果表明,当大豆蛋白粉添加比例为15%左右时,麦芯粉的品质有明显提升,不仅其蛋白质含量显著增加,且所制成面团的筋力、延伸性等均有明显改良。