西班牙肉鸡企业的饲养模式

高蛋白原料的价格(像大豆)影响鸡肉价格。企业追求效益最大化就应该调整肉鸡日粮中的蛋白水平。Nutreco公司已经开发出一套灵活的方法来计算获得最大效益的最低日粮蛋白水平。     

Effects of air temperature,soil temperature and soil moisture on growth and development of tomato itself and grafted on its own and egg-plant rootstock

The problem was studied whether tomatoes, grown in a hot and arid climate, benefit from grafting on egg-plant, which is highly efficient in water uptake. Growth and development of tomato (T), tomato grafted on its own rootstock ($\text{T}\text{T}$) and tomato grafted on egg-plant rootstock ($\text{T}\text{E}$) were compared at air temperatures of 28°C during the day and 18°C during the night ($\text{28}\text{18}$) and at 28°C constantly ($\text{28}\text{28}$), at soil temperatures of 14, 21 and 28°C with the following soil moisture regimes: wet (W₁), medium (W₂) and dry (W₃).At $\text{28}\text{18}$ and $\text{28}\text{28}$ water consumption was about equal, but the transpiration ratio at $\text{28}\text{28}$ was twice as high as that at $\text{28}\text{18}$. The latter conditions gave a much stronger plant with more fruits. At a soil temperature of 14°C water use was strongly reduced. The transpiration ratio increased with the soil temperature. Differences in plant type were small. At the highest soil temperature of 28°C fruit growth was strongly reduced. At lower soil moisture levels less water was used and the transpiration was lower. Plant type was correlated herewith.Vegetative growth of $\text{T}\text{T}$ was weaker than of T, but generative growth was stimulated. The strong E rootstock stimulated vegetative growth at high air and soil temperature, but fruit growth was very poor under these conditions; at a low soil temperature of 14°C vegetative growth was also reduced.The hope that the E rootstock would be beneficial for fruit growth at high temperatures was not fulfilled.An additional experiment in a growth-room at 23°C showed that under conditions of moisture stress there was no difference in water potential between leaves of $\text{T}\text{T}$ and $\text{T}\text{E}$.     

Adaptive conjoint analysis to determine perceived risk factors of farmers, veterinarians and AI technicians for introduction of BHV1 to dairy farms

A study was carried out to determine the possibility of a more-closed farming system for (Dutch) dairy farms. The objective of the study was to provide effective and economically profitable management advice for improving the animal-health status of farms. Management measures will only be successfully applied if supported by farmers and their advisors (such as veterinarians). Therefore, the perception of farmers and advisors of the importance of various risk factors for the introduction of diseases to a farm was determined by using bovine herpes virus type 1 (BHV1) as an example.

As part of the study, an evening-long workshop was organized and run thrice. In total, 49 farmers, veterinarians and AI technicians participated in these workshops. The computerized questionnaire technique was based on adaptive conjoint analysis (ACA). ACA has the advantage that participants can work with a large number of risk factors in a relatively short period of time. Another advantage of ACA (compared with standard questionnaires) is that the answers from each participant can be checked with regard to consistency with respect to the importance assigned to them. Data from participants with inconsistent responses can be excluded from further analyses. The results of the ACA interview were compared with the risk factors reported in the literature as being associated with BHV1 status (e.g. purchase of cattle, participation in cattle shows) and with farmers' actual management to prevent the introduction of diseases.

The workshop participants were all operating in the dairy sector and they seemed well aware of the risk of direct animal contacts for the introduction of BHV1. Farmers thought visitors to be more risky than did AI technicians and (especially) veterinarians. Farmers who purchased cattle or participated in cattle shows were of the opinion that the risks of direct animal contacts were more important than did farmers who were not involved in those practices. Farmers whose farms were BHV1-positive (and participated in cattle shows more often) thought the risk of participation smaller than did farmers with BHV1-negative farms.     

Oxidative degradation of lipids during mashing

Although hardly any polyunsaturated fatty acids (PUFAs) are present in the endproduct, the ingredients used for the production of beer contain a high concentration of PUFAs, such as linolic and linolenic acid. These compounds are readily oxidized, resulting in the formation of lipid-derived products that reduce the taste and quality of beer enormously. During mashing relatively high amounts of PUFAs are exposed to atmospheric oxygen at a relatively high temperature. This makes mashing a critical step in the brewing process with regard to the formation of lipid-derived off-taste products. F1 phytoprostane (PPF1) changes in antioxidant capacity and monohydroxy fatty acids (OH-FAs) were used as markers for the detection of oxidative damage to fatty acids during mashing. The pattern of OH-FA formation indicates that enzymatic oxidation of PUFAs is more important than nonenzymatic oxidation during the mashing process. Nevertheless, substantial nonenzymatic radical formation is evident from the increase of specific OH-FAs and PPF1s. It was found that a low oxygen tension reduces oxidative damage and gives a high antioxidant capacity of the mashing mixture. This indicates that mashing should be done under low oxygen pressure.     

Reward-predictive cues enhance excitatory synaptic strength onto midbrain dopamine neurons

Using sensory information for the prediction of future events is essential for survival. Midbrain dopamine neurons are activated by environmental cues that predict rewards, but the cellular mechanisms that underlie this phenomenon remain elusive. We used in vivo voltammetry and in vitro patch-clamp electrophysiology to show that both dopamine release to reward predictive cues and enhanced synaptic strength onto dopamine neurons develop over the course of cue-reward learning. Increased synaptic strength was not observed after stable behavioral responding. Thus, enhanced synaptic strength onto dopamine neurons may act to facilitate the transformation of neutral environmental stimuli to salient reward-predictive cues.     

A comparison of alternative modelling approaches to evaluate the European forest carbon fluxes

The European forest carbon balance studied by various methods shows different results. We compared the regional and national net primary production (NPP) estimated by the forest inventory-based model EFISCEN and the climate-based terrestrial ecosystem models (TEMs: BIOME-BGC, ORCHIDEE, and JULES), and single forests NPP derived from the international network of eddy-covariance towers (FLUXNET). In addition, the paper presents the net ecosystem production (NEP) and the net biome production (NBP) calculated with EFISCEN and discusses the influence of forest management onto carbon fluxes. We aimed to better understand the variance between EFISCEN and TEMs NPP estimates, and to improve the assessment of European forest mitigation potential for the year 2005.