The effect of daily energy intake on growth rate and composition of weight gain in pigs

An experiment with 29 crossbred female growing pigs (Dutch Landrace × Dutch Yorkshire) was carried out to measure the effect of daily energy intake on growth rate, N retention (according to the balance method) and composition of the weight gain. The weight gain composition was analysed by slaughtering pigs at regular intervals between 25 and 110 kg live weight. Two levels of daily energy intake, at an adequate protein intake, were used, and pigs on both treatments were slaughtered at the same age.Differences in daily energy intake affected growth rate and composition of the weight gain. Restriction of the daily energy intake by 20% caused a 15% lower live weight gain and a 12% lower N retention. Carcass muscle growth was 8% lower and fatty tissue growth was lower by 28%. Growth of bone was unaffected. Chemical analysis of different parts of the body revealed that reducing the daily energy intake by 20% caused an 8% lower protein deposition and a 28% lower fat deposition in the total body. However, there were differences between different anatomical parts of the body.Efficiency of pig meat production is discussed in relation to the effects of energy supply on weight gain composition.     

Analysis of polar metabolites of organophosphorus insecticides on an anion-exchange chromatographic column

A simple and rapid procedure is described for the qualitative and quantitative analysis of metabolites of malathion and other insecticides. The omission of an extraction at low pH, and mild conditions of anion-exchange chromatography on QAE-Sephadex prevent the degradation of a malathion metabolite, S-(1-carboxy-2-ethoxycarbonyl)-ethyl O,O-dimethyl phosphorothioate (malaoxon α-carboxylic acid), which takes place under strongly acid conditions. Disadvantages of the commonly used fractionation of malathion and malaoxon metabolites based on partitioning are discussed.     

Passive immunization of guinea pigs with llama single-domain antibody fragments against foot-and-mouth disease

Foot-and-mouth disease (FMD) is a highly contagious disease that occasionally causes outbreaks in Europe. There is a need for therapies that provide rapid protection against FMD in outbreak situations. We aim to provide such rapid protection by passive immunization with llama single-domain antibody fragments (VHHs). Twenty-four VHHs binding serotype O FMDV in vitro were isolated from immunized llamas by phage display and expressed in bakers yeast for further characterization. They recognized four functionally independent antigenic sites. Six strongly FMDV neutralizing VHHs bound to a peptide representing the GH-loop of viral protein 1 known to be involved in binding to the cellular receptor of FMDV. Clone M8, recognizing this antigenic site, and clone M23, recognizing another antigenic site, showed synergistic in vitro virus neutralization. Three FMDV specific VHHs were PEGylated in order to decrease their rapid blood clearance and thus enable in vivo guinea pig protection experiments. Passive immunization with individual VHHs showed no protection, but a mixture of M8 and M23 showed partial transient protection. The protection afforded by these VHHs was however low as compared to the complete protection afforded by convalescent guinea pig serum. In contrast, these VHHs showed far more efficient in vitro FMDV neutralization than convalescent guinea pig serum. This lack of correlation between in vitro neutralization and in vivo protection lends further credence to the notion that opsonophagocytosis of FMDV is important for protection in vivo.     

A case study on infiltration into dry clay soil I. Morphological observations

Infiltration patterns of water into four dry clay soils with different macrostructures were determined in the field as a function of application rate (i = 4?80 mm/h) and applied quantity (q = 2.5?40 mm), using methylene blue as a tracer. Stains on the walls of large vertical pores (dominantly planar voids) occurred as small vertical bands and were observed and counted to a depth of 1 m after excavation of the 0.5 m² plots. Deep infiltration through large pores, as demonstrated by occurrence of stained bands, could be manipulated by varying application rates and applied quantities. The number of stained bands was always very low, occupying at the most an estimated 2% of the available vertical surface area of large prisms, and (for each stained band) a horizontal cross-sectional area of 60 cm² or more. Infiltration was deeper, at comparable flow regimes, in two soils with strongly developed prisms, as compared with two soils with moderately developed prisms. Deep infiltration occurred along vertical prism faces where grass roots were also concentrated.     

Differentiation of foot-and-mouth disease-infected pigs from vaccinated pigs using antibody-detecting sandwich ELISA

The presence of serum antibodies for nonstructural proteins of the foot-and-mouth disease virus (FMDV) can differentiate FMDV-infected animals from vaccinated animals. In this study, a sandwich ELISA was developed for rapid detection of the foot-and-mouth disease (FMD) antibodies; it was based on an Escherichia coli-expressed, highly conserved region of the 3ABC nonstructural protein of the FMDV O/TW/99 strain and a monoclonal antibody derived from the expressed protein. The diagnostic sensitivity of the assay was 98.4%, and the diagnostic specificity was 100% for na?ve and vaccinated pigs; the detection ability of the assay was comparable those of the PrioCHECK and UBI kits. There was 97.5, 93.4 and 66.6% agreement between the results obtained from our ELISA and those obtained from the PrioCHECK, UBI and CHEKIT kits, respectively. The kappa statistics were 0.95, 0.87 and 0.37, respectively. Moreover, antibodies for nonstructural proteins of the serotypes A, C, Asia 1, SAT 1, SAT 2 and SAT 3 were also detected in bovine sera. Furthermore, the absence of cross-reactions generated by different antibody titers against the swine vesicular disease virus and vesicular stomatitis virus (VSV) was also highlighted in this assay's specificity.     

Capturing chromosome conformation

We describe an approach to detect the frequency of interaction between any two genomic loci. Generation of a matrix of interaction frequencies between sites on the same or different chromosomes reveals their relative spatial disposition and provides information about the physical properties of the chromatin fiber. This methodology can be applied to the spatial organization of entire genomes in organisms from bacteria to human. Using the yeast Saccharomyces cerevisiae, we could confirm known qualitative features of chromosome organization within the nucleus and dynamic changes in that organization during meiosis. We also analyzed yeast chromosome III at the G1 stage of the cell cycle. We found that chromatin is highly flexible throughout. Furthermore, functionally distinct AT- and GC-rich domains were found to exhibit different conformations, and a population-average 3D model of chromosome III could be determined. Chromosome III emerges as a contorted ring.     

Did lack of spawners cause the collapse of the European eel,Anguilla anguilla?

Since the 1980s, a 90% decline in recruitment of European eel, Anguilla anguilla (L.), has occurred across most of Europe. Whether the continental stock has equally declined is uncertain. This study compiles available landings statistics since the beginning of the 20th century and identifies trends over time and space, using a statistical model that takes varying levels of reporting into account. Landings in the pre‐1940s reached over 40 000 tonnes yr^?1, declined during World War II, rose to a peak of 40 000 tonnes yr^?1 in the 1960s (coincident with a peak in re‐stocking) and dropped to an all time low of <20 000 tonnes yr^?1 in the 1990s. The decline in recruitment since the early 1980s was preceded by a decline in landings two or more decades earlier, indicating a decline of the continental stock. Considering the continental stock and the spawning stock must have declined in parallel, insufficient spawning stock biomass might have caused the recruitment collapse currently observed.     

Simulation of Nile tilapia (Oreochromis niloticus niloticus L.) culture in ponds, through individual-based modelling, using a population dynamic approach

A simulation model for the production of the Nile tilapia (Oreochromis niloticus niloticus L.) for mixed‐ or mono‐sex culture and for poly‐culture with the African catfish (Clarias gariepinus Burchell 1822) or African snakehead (Parachanna obscura Günther 1861) is presented. The model is based on an exponential decay model used in population dynamics and follows an individual‐based approach. The model consists of a tilapia sub‐model representing population dynamics, growth and recruitment and a predator sub‐model representing the predation process and population dynamics and growth of the used predator. The model was calibrated with data on mixed‐ or mono‐sex culture of Nile tilapia and for poly‐culture with the African catfish or African snakehead obtained in Congo Brazzaville and validated with similar data from the Philippines, Thailand and the Ivory Coast. The model visualized major underlying processes in tilapia farming and aspects for further improvement of the model; growth is one of the most sensitive input parameters and should be quantitatively related to feeding level and feed quality; length at first maturity and quantification of the recruitment of Nile tilapia has a relatively large influence and recruitment should be related to the length of the females; prey–predator relations are too coarse and should be more fine‐tuned with the relation between prey size and predator size. Incorporation of these features would provide the basis of a model that can serve as a predictive and decision‐making support tool.