R. De Wilde

A methodology for the calculation of farm level nitrogen and phosphorus balances in Flemish agriculture

Abstract Since the early 1990s, Flemish agriculture has been confronted with serious nutrient problems. Recently, the Flemish Government started encouraging farmers to take responsibility for the manure problem. This was done by giving them the choice between a manure administration system, based on fixed standards, or a nutrient balance system. In this project a methodology for the composition of nutrient balances at farm level in Flanders was developed. This methodology defines input–output models for the different sectors (cattle, pigs and poultry) and fixes rules on how to determine quantities and nutrient contents for several products. In addition, nutrient flows were followed during 1 year on 40 Flemish farms in different sectors and a mineral balance was calculated for each of them. Four major restrictions to the accurate calculation of farm level nutrient balances were identified: (1) the wide variability that is allowed between actual and reported nutrient composition of concentrated feed; (2) the estimates of the amount and composition of manure; (3) the assessment of changes in standing stock on the farm between the beginning and end of the reporting period and (4) the accuracy of the data supplied by the farmers.

Enhanced specific antibody response to bovine serum albumin in pigeons due to L-carnitine supplementation.

1. Thirty adult female pigeons (Columba livia domestica) were randomly divided into 3 equal groups; the 1st and 2nd groups were immunised with bovine serum albumin (BSA) at 0 and 20 d, the 2nd group also received 1 g L-carnitine per litre of drinking water from -5 to 25 d post-immunisation (dpi) and the 3rd group, a control group, received neither treatment. 2. Body weights and serum samples were taken at 0, 5, 10, 15, 20, 25, 30 and 35 dpi. 3. Both BSA-specific IgG and IgM responses were enhanced by about 10% by L-carnitine supplementation. 4. L-carnitine supplemented pigeons showed a higher water consumption. Body weight loss during the onset of the immune response showed a slight tendency to be counteracted by L-carnitine supplementation. 5. The impact of L-carnitine on resistance and resilience to an immunological challenge is discussed.

Protein and energy retentions in pregnant and non-pregnant gilts. II. Energy retention

Abstract Energy retention, realised during pregnancy and assessed by means of the slaughter technique, has been studied in a group of eleven gilts. They were compared to a control group of littermates, analysed at the mating of the first group, and to a third group of non-pregnant (NP) sisters, slaughtered together with the pregnant (P) gilts near parturition (111 days of pregnancy). The total intake of metabolisable energy (ME) amounted to 2648 ± 85 MJ. The NP gilts retained more energy (44.6 MJ) than the P gilts, resulting from a higher energy retention as fat (68.3 MJ) and a lower energy retention as protein (23.7 MJ). Assuming the same maintenance requirement for P and NP gilts of 400 kJ/kg W 0.75 /day, the efficiencies for net energy retention ( k p+f ) amounted to 0.42 ± 0.15 in NP-gilts and 0.39 ± 0.23 in P-gilts. Otherwise, by application of the efficiency coefficients of 0.48 for protein energy retention and 0.77 for fat energy retention (Thorbek, 1975), maintenance energy figures of 513 ± 60.6 and 502 ± 71.1 kJ ME/day/kg W 0.75 were obtained for NP- and P-gilts, respectively. This difference was not significant, however. The figure of 0.33, obtained as the efficiency coefficient for energy retention due to pregnancy, is rather speculative because of the low energy retention relative to the total energy retention in the genital organs, and the important variability within the animals.

Analysis of carnitine, betaine, γ-butyrobetaine, and separate short-chain acylcarnitines in pigeon plasma, crop milk and tissues by HPLC coupled with UV-detection

Carnitine, betaine, γ-butyrobetaine and separate carnitine esters are determined in blood plasma, crop milk, liver, heart and breast muscle of pigeons (Columba livia domestica) by means of HPLC with photometric detection at 245 nm. The method can be generally applied for samples of animal origin.

Cloning and functional analysis of the ecdysteroid receptor complex in the opossum shrimp Neomysis integer (Leach, 1814).

In this paper, the non-target effects of tebufenozide were evaluated on the estuarine crustacean, the opposum shrimp Neomysis integer (Leach, 1814). Tebufenozide is a synthetic non-steroidal ecdysone agonist insecticide and regarded as potential endocrine-disrupting chemical (EDC). N. integer is the most used crustacean in ecotoxicological research in parallel to Daphnia sp. and has been proposed for the regulatory testing of potential EDCs in the US, Europe and Japan. Major results were: (i) cDNAs encoding the ecdysteroid receptor (EcR) and the retinoid-X-receptor (RXR), were cloned and sequenced, and subsequent molecular phylogenetic analysis (maximum likelihood and neighbor-joining) revealed that the amino acid sequence of the ligand binding domain (LBD) of N. integer EcR (NiEcR) clusters as an outgroup of the Crustacea, while NiRXR-LBD clusters in the Malacostracan clade (bootstrap percentage=75%). (ii) 3D-modeling of ligand binding to NiEcR-LBD demonstrated an incompatibility of the insecticide tebufenozide to fit into the NiEcR-ligand binding pocket. This was in great contrast to ponasterone A (PonA) that is the natural molting hormone in Crustacea and for which efficient docking was demonstrated. In addition, the heterodimerization of NiEcR-LBD with the common shrimp Crangon crangon (Linnaeus, 1758) RXR-LBD (CrcRXR-LBD) was also modeled in silico. (iii) With use of insect Hi5 cells, chimeric constructs of NiEcR-LBD and CrcRXR-LBD fused to either the yeast Gal4-DNA binding domain (DBD) or Gal4-activation domain (AD) were cloned into expression plasmids and co-transfected with a Gal4 reporter to quantify the protein-protein interactions of NiEcR-LBD with CrcRXR-LBD. Investigation of the ligand effect of PonA and tebufenozide revealed that only the presence of PonA could induce dimerization of this heterologous receptor complex. (iv) Finally, in an in vivo toxicity assay, N. integer juveniles were exposed to tebufenozide at a concentration of 100 μg/L, and no effects against the molting process and nymphal development were scored. In conclusion, the in vitro cell reporter assay, based on NiEcR-LBD/CrcRXR-LBD heterodimerization in Hi5 cells and validated with the natural ecdysteroid hormone PonA, represents a useful tool for the screening of putative EDCs. As a test example for non-steroidal ecdysone agonist insecticides, tebufenozide had no negative effects on NiEcR/RXR receptor dimerization in vitro, nor on the molting process and nymphal development of N. integer at the tested concentration (100 μg/L) in vivo.

Comparison of halothane-sensitive and halothane-resistant litter-mate pigs for growth, carcass composition, hormonal status and energy balance

Abstract In three experiments with a total of 116 Belgian Landrace pigs, the differences between halothane-sensitive (HS) and halothane-resistant (HR) litter-mates were investigated with respect to growth performance, carcass composition, serum level of insulin and thyroid hormones and energy balance. In ad libitum feeding conditions (Experiment 1), HR pigs ate 9% more than HS pigs, and had a higher growth rate but a fatter carcass. By diluting the ration for the HR pigs, with cellulose (Experiment 2), the differences disappeared, since the HR pigs did not compensate by a higher intake on this bulky ration. In Experiment 3, the pigs were hand-fed on two restricted scales (80 and 90% of the ad libitum feeding intake of the previous experiments) in order to obtain by regression an estimation of the maintenance requirements of HS and HR pigs. Total metabolizable energy (ME) intake and total energy retention (from empty body analyses) were measured. In the HS pigs, only 34% of the ME intake was retained compared to 38% for the HR pigs. The possibility cannot be excluded that this difference, besides the less efficient energetic conversion of the ME for production in the HS pigs, is partly due to a higher metabolic rate in these pigs at maintenance energy level. In the three experiments, no consistent differences were noted between HS and HR pigs with regard to serum levels of thyroid hormones, but there was a significantly higher response to serum insulin after a meal in the HR pigs than in the HS pigs.

Binding of biotinylated legume seed lectins with glycoproteins in blotted receptor-analogs: influence of incubation pH

Abstract SDS–PAGE and Western blotting of lectin inhibitors (bovine and porcine plasma powder, whole egg powder and fetuin) was performed and blots were incubated with several biotinylated lectins commercially available ( Phaseolus vulgaris E , Pisum sativum , Lens culinaris , Vicia faba ). In order to study the effect of pH on the binding of the lectins to glycoproteins present in the inhibitors, identical blots were incubated in buffers with different pH values, i.e. 3–7, respectively. Binding capacity of lectins to the glycoproteins in the inhibitors was very dependent on pH condition during incubation: for all the lectins involved in this experiment, pH values lower than 4 inhibited the binding process considerably. Results are discussed taking into account the low pH values prevailing in the stomach of pigs.