美国鸡肉的成功故事给我国白羽肉鸡行业带来的思考

美国肉鸡行业的主要特点：约40家公司采用垂直一体化模式,约29500家农户签约养殖,产量占总产量的95％。剩余5％是公司自营农场,每年养殖总数达90亿只鸡,其中19％的鸡肉用于出口（由于美国相对低廉的饲料价格,美国鸡肉的国际竞争力较高）。美国共有185家屠宰厂,鸡肉是最受欢迎的肉类。1992年,鸡肉取代牛肉成为美国主导肉类,过去40年总肉类消费量持平,鸡肉是怎样夺得如此高的市场份额的？     

Combining novel monitoring tools and precision application technologies for integrated high-tech crop protection in the future (a discussion document)

The possibility of combining novel monitoring techniques and precision spraying for crop protection in the future is discussed. A generic model for an innovative crop protection system has been used as a framework. This system will be able to monitor the entire cropping system and identify the presence of relevant pests, diseases and weeds online, and will be location specific. The system will offer prevention, monitoring, interpretation and action which will be performed in a continuous way. The monitoring is divided into several parts. Planting material, seeds and soil should be monitored for prevention purposes before the growing period to avoid, for example, the introduction of disease into the field and to ensure optimal growth conditions. Data from previous growing seasons, such as the location of weeds and previous diseases, should also be included. During the growing season, the crop will be monitored at a macroscale level until a location that needs special attention is identified. If relevant, this area will be monitored more intensively at a microscale level. A decision engine will analyse the data and offer advice on how to control the detected diseases, pests and weeds, using precision spray techniques or alternative measures. The goal is to provide tools that are able to produce high-quality products with the minimal use of conventional plant protection products. This review describes the technologies that can be used or that need further development in order to achieve this goal.     

Impact of Maillard reaction on immunoreactivity and allergenicity of the hazelnut allergen Cor a 11

Few studies exist on the influence of processing methods on structural changes and allergenic potential of hazelnut proteins. This study focused on the effect of glycation (Maillard reaction) on the immunoreactivity and degranulation capacity of the purified hazelnut 7S globulin, Cor a 11. After heating, the extent of the Maillard reaction, sensitivity to proteolysis, binding of human IgE or rabbit IgG, and degranulation capacity were analyzed. Changes in electrophoretic mobility, amount of free amino groups, and contents of bound sugar and fructosamine indicated that glycation of Cor a 11 occurred at all conditions. Glycation at 37 °C did not influence the specific IgG or IgE binding and was decreased after heating at 60 and 145 °C. Heating, with or without glucose, at 145 °C increased basophil degranulation capacity. The results suggest that glycation of Cor a 11 at 60 and 145 °C may decrease the IgE/IgG binding properties but not the degranulation capacity of basophils. This is possibly related to aggregation of the proteins as a result of the Maillard reaction.     

Lactoferrin, a glycoprotein with immunomodulatory and mast cell stabilising properties, in skin of horses suffering from Culicoides hypersensitivity

Lactoferrin (LF), a glycogen of the transferrin family with anti-bacterial and immunomodulatory properties, is expressed in various secretions and tissues. Cutaneous LF serves as a mast cell stabilising compound, modulates T cell activity and is found during IgE-mediated late phase reactions at allergen challenged sites. Culicoides hypersensitivity (CHS) in horses is a common IgE-mediated allergic dermatitis, characterised by an early and late phase cutaneous reaction upon allergen challenge. The aim of the study presented here was to examine whether LF mRNA expression in skin biopsies from horses affected by CHS prior to and 4h following intradermal challenge with a commercial C. nubeculosus extract is modified in comparison to skin biopsies from non-affected horses. In order to obtain reliable data, real time PCR was performed and genes of interest were normalized using three different housekeeping genes, beta-actin, GAPDH, beta-2-microglobulin. In comparison to non-affected horses, higher variation in LF mRNA levels both prior to and post-intradermal challenge with C. nubeculosus extract was seen in horses affected by CHS. However, the statistical analysis demonstrated that LF mRNA expression was not significantly different between CHS affected and non-affected horses prior to intradermal challenge with C. nubeculosus extract. Intradermal injection of C. nubeculosus extract did not result in local upregulation of LF mRNA at 4h post-injection. LF mRNA expression was therefore not significantly different pre- or post-intradermal challenge with C. nubeculosus extract in either group. Our data indicate that clinically normal skin of horses affected by CHS is not characterized by modified maintenance levels of LF mRNA. In contrast to human skin allergen challenged sites, LF mRNA levels in horses affected by CHS are not significantly different to that of control sites at 4h post-injection of C. nubeculosus extract.     

Feed management for Pacific white shrimp Litopenaeus vannamei under semi‐intensive conditions in tanks and ponds

To improve feed management strategies for the semi‐intensive culture of Litopenaeus vannamei, outdoor tank and pond trials were conducted. In the tank trial, shrimp (35 shrimp/m², n = 4) were offered feed for 6 weeks based on a standard feeding protocol (SFP, designed as T100) with five variations (T80:90:100, T90, T90:100, T100:110, T110) of this protocol produced by varying the feed inputs and expressing the treatments as a percentage. Results demonstrated no significant differences in survival rate and feed conversion ratio (FCR) among treatments. The mean final weight and final biomass in the treatments T100:110 and T110 were significantly higher than those in treatment T90 but were not different from the other treatments. In the pond trial, juvenile shrimp (28 shrimp/m², n = 4) were stocked into twelve 0.1‐ha ponds over a 16‐week period. Three feeding protocols were evaluated including a SFP, a 10% reduction in the SFP (SFP:90), and a variable feed input (SFP:80:90:100), which included 80% SFP at week 4th–8th, 90% SFP from week 9th–12th and 100% SFP for week 12th–16th. There were no significant differences in growth performance and economic return among treatments. Based on previous studies, in which higher feed inputs were evaluated, and results of this study, it does not appear to be economically beneficial to use high feed inputs. Instead, feed input could be either applied at a standard ration to optimize growth and economic return or at restricted rations to reduce FCR (feed cost) albeit at the expense of some growth.     

The Ultrastructure of the Trophoblast Fossal Regions in the Pig Placenta During Pregnancy: Its Steroidogenic Features*

The fine structural changes of the trophoblast covering the fossae of the porcine placenta between the 21st day of pregnancy and term are described. Considering the characteristic features of cells, six morphological stages in the development of the fetal placental fossae were distinguished. Three types of trophoblast cells were recognized: light, dark and intermediates. The light cells were characterized by whorls of strongly convoluted SER channels, dense granules were sometimes associated with these whorls and by lipid droplets. They were particularly numerous in the second month and the last week of pregnancy. With the ultrastructural investigation, ultracytochemical and histochemical methods were used for the detection and localization of 3 β-hydroxysterols and 3 β-hydroxysteroid dehydrogenase activity. The localization of 3 β-hydroxysterols was studied by the digitonin reaction adapted to electron microscopy by Ökrös (1968). The digitonin 3 β-hydroxysteroid complexes were most numerous during the second month and last week of pregnancy. They were located mainly in contact with granules in the region of the SER whorls and in the matrix of mitochondria. The 3 β-hydroxysteroid dehydrogenase activity was investigated with the use of dehydroepiandrosterone and dehydroisoandrosterone as substrates. The enzyme activity in the trophoblast determined with dehydroepiandrosterone increased in the 52nd and 106th day of pregnancy. The cells of the fossae showed higher activity than that observed on the sides and tops of the folds. Lower activity was exhibited by dehydroepiandrosterone. The finding suggest that the trophoblast of the fossae is a region where synthesis of steroid hormones takes place and that the light cells are involved in this process. The results correspond to biochemical findings regarding progesterone and estradiol concentrations in the maternal and fetal circulation and estrogen distribution in fetal organs and placenta.     

国际市场上鸡蛋分级的趋势

食品科技的发展，前沿的自动化与软件功能将会主导鸡蛋分级市场，同时为用户“提供差异化服务”。经过不断的提升产能和功能的“竞赛”，现代的鸡蛋分级设备被逐渐引入食品科技元素：高技术工艺在其它领域（比如肉类工业）的应用非常突出．但对于壳蛋分级则不太适用．但随着食品安全需求越来越受到重视，这方面有了显著的变化。