Allel Chedad

Computer-assisted image analysis to quantify daily growth rates of broiler chickens.

1. The objective was to investigate the possibility of detecting daily body weight changes of broiler chickens with computer-assisted image analysis. 2. The experiment included 50 broiler chickens reared under commercial conditions. Ten out of 50 chickens were randomly selected and video recorded (upper view) 18 times during the 42-d growing period. The number of surface and periphery pixels from the images was used to derive a relationship between body dimension and live weight. 3. The relative error in weight estimation, expressed in terms of the standard deviation of the residuals from image surface data was 10%, while it was found to be 15% for the image periphery data. 4. Image-processing systems could be developed to assist the farmer in making important management and marketing decisions.

Kinetics of folding and unfolding of goat α‐lactalbumin

The equilibrium unfolding and the kinetic folding and unfolding of goat α‐lactalbumin (GLA) were studied by near‐ and far‐ultraviolet circular dichroism (CD) and by stopped‐flow fluorescence spectroscopy. Specifically, the influence of environmental conditions such as pH and Ca2+ binding was examined. Compared to the apo‐form, the Ca2+‐bound form was found to be strongly stabilized in equilibrium conditions at pH 7.5 and 25°C. The kinetics of the refolding of apo‐GLA show a major change of fluorescence intensity during the experimental dead‐time, but this unresolved effect is strongly diminished in holo‐GLA. In both cases, however, the chevron plots can adequately be fitted to a three‐state model. Moreover, double‐mix stopped‐flow experiments showed that the native state (N) is reached through one major pathway without the occurrence of alternative tracks. In contrast to the homologous bovine α‐lactalbumin (BLA), the compactness of GLA is strongly influenced by the presence of Ca2+ ions. Unlike the two‐state transition observed in guanidine hydrochloride (GdnHCl)‐induced equilibrium denaturation experiments at higher pH, an equilibrium intermediate state (I) is involved in denaturation at pH 4.5. In the latter case, analysis of the kinetic data makes clear that the intermediate and the unfolded states (U) show practically no Gibbs free energy difference and that they are in rapid equilibrium with each other. A possible explanation for these variations in stability and in folding characteristics with pH could be the degree of protonation of His107 that directly influences non‐native interactions. Variation of environmental conditions and even small differences in sequence, therefore, can result in important effects on thermodynamic and folding parameters. Proteins 2004.

Neural recognition systems for swine cough

Coughing is one of the most frequent presenting symptoms of many diseases affecting the airways and the lungs of humans and animals. The aim of this paper is to build up an intelligent alarm system that can be used for the early detection of cough sounds in piggeries. Registration of coughs from different pigs in a metallic chamber was done in order to analyse the acoustical signal. A new approach is presented to distinguish cough sounds from other sounds like grunts, metal clanging and noise using neural networks (NN) as classification method. Other signals (grunts, metal clanging, etc.) could also be detected. Self-organising maps are used for visualisation of data relationships. Several types of NN are compared with statistical methods for the classification of the cough sounds. The early detection of coughs can be used for the construction of an intelligent alarm that can inform about the presence of a possible viral infection.

An intelligent alarm for early detection of swine epidemics based on neural networks

Coughing is one of the most frequent presenting symptoms of many diseases affecting the airways and the lungs of humans and animals. The aim of this research is to build an intelligent alarm system that can be used for the early detection of cough sounds in pig houses. Registration of coughs from different pigs in a metallic chamber was done in order to analyze the acoustical signal. A new approach is presented to distinguish cough sounds from other sounds like grunts, metal clanging, and noise using neural network classification methods. Other signals (grunts, metal clanging, etc.) could also be detected. A hybrid classifier is proposed that achieves the highest classification accuracy in both the off-line and the on-line detection of coughs and other sounds. The best correct classification performance was obtained with a hybrid classifier that classified coughs and metal clanging separately from other sounds, giving better results compared to a multi-layer perceptron alone. The hybrid classifier, which consisted of a 2-class probabilistic neural network and a 4-class multi-layer perceptron, gave high discrimination performance in the case of grunts and noise (91.3% and 91.3% respectively) and a performance of 94.8% for correct classification in the case of coughs. The early detection of coughs can be used for the construction of an intelligent alarm that can signal the presence of a possible viral infection so that early treatment can be implemented.

Tryptophan to phenylalanine substitutions allow differentiation of short- and long-range conformational changes during denaturation of goat α-lactalbumin

To test the occurrence of local particularities during the unfolding of Ca2+‐loaded goat α‐lactalbumin (GLA) we replaced Trp60 and ‐118, either one or both, by Phe. In contrast with alternative studies, our recombinant α‐lactalbumins are expressed in Pichia pastoris and do not contain the extra N‐terminal methionine. The substitution of Trp60 leads to a reduction of the global stability. The effect of the Trp118Phe substitution on the conformation and stability of the mutant, however, is negligible. Comparison of the fluorescence spectra of these mutants makes clear that Trp60 and ‐118 are strongly quenched in the native state. They both contribute to the quenching of Trp26 and ‐104 emission. By the interplay of these quenching effects, the fluorescence intensity changes upon thermal unfolding of the mutants behave very differently. This is the reason for a discrepancy of the apparent transition temperatures derived from the shift of the emission maxima (Tm,Fl λ) and those derived from DSC (Tm,DSC). However, the transition temperatures derived from fluorescence intensity (Tm,Fl int) and from DSC (Tm,DSC), respectively, are quite similar, and thus, no local rearrangements are observed upon heat‐induced unfolding. At room temperature, the occurrence of specific local rearrangements upon GdnHCl‐induced denaturation of the different mutants is deduced from the apparent free energies of their transition state obtained from stopped‐flow fluorescence measurements. By ϕ‡‐value analysis it appears that, while the surroundings of Trp118 are exposed in the kinetic transition state, the surroundings of Trp60 remain native. Proteins 2005.

An equilibrium and a kinetic stopped-flow fluorescence study of the binding of various metal ions to goat alpha-lactalbumin.

Various metal ions bind to the protein α-lactalbumin prepared from goat milk. The stability of the protein after metal binding is compared with that of the apo-protein by monitoring the fluorescence of the tryptophan residues under equilibrium conditions. The kinetics of the metal binding is studied by stopped-flow fluorescence spectroscopy. By means of the Arrhenius plots, the activation energy with regard to the binding of the different ions is determined.

Behaviour of Chickens Towards Automatic Weighing Systems

Abstract In previous studies it was found that automatic broiler weighing systems deal with some accuracy problems. Researchers reported poor agreement between automatic and manual mean weighing used as a reference. The difference was observed especially after 4 weeks and this was explained by assuming that the weighing system is less visited by heavier chickens at the end of the production period. The objective of the research reported in this paper was to test this hypothesis under practical production conditions. From the image analysis, the higher formulated hypothesis that the system was used less frequently by heavier animals’ could be confirmed.

Egg Shell Temperature as an Indicator for Embryonic Response

In relation to the percentage of hatch out of eggs in an incubator, the maintenance of the optimum incubation temperature (37.2 – 37.8 °C) is a critical factor. The temperature around the embryo depends on three factors: (1) the air temperature of the incubator, (2) the transport of heat between egg and environment and (3) the time-variable heat production of the embryo. In commercial incubators, the transport of heat between the egg and its environment is performed by convection. The objective of this research is to use infrared thermography to quantify the egg shell temperature and analyse the resulting egg shell temperatures in relation to the micro environment in an incubator of 300 chicken eggs. Although the setpoint of air temperature is 37.7°C, the egg shell temperatures at day 17 varied from 37.15°C towards 39.06°C. Regardless of these large egg shell temperature gradients, 222 chickens hatched well out of the total number of 300 incubated eggs. Using the egg shell surface temperatures, the mean convection coefficient at the beginning and at the end of the incubation process is determined.

Data-Based Statistical Modelling of Body-Temperature Out of Infrared Imaged Skin-Temperature

Abstract Variation of deep body- and skin-temperature on an individual Belgian Landrace piglet is examined during the total 11-day evolution of a respiratory infection disease by respectively telemetric deep body-temperature registration and contactless infrared-imaging of the animal free movement area. The described research is aimed firstly to show a relationship between deep body- and skin-temperature and secondly to model deep body-temperature out of skin-temperature by applying local linear smoothing to the experimental data-base.