Multilocus genotyping of Cryptosporidium and Giardia in non-outbreak related cases of diarrhoea in human patients in Belgium.

Stool samples from Belgian patients suffering from abdominal pain and/or diarrhoea were examined for Cryptosporidium and Giardia. Cryptosporidium-positive samples were genotyped using the 70 kDa heat shock protein and the 60 kDa glycoprotein (GP60) genes: C. hominis was identified in 54.2% and C. parvum in 45.8% of the samples. Sequencing at the GP60 locus indicated that subgenotype IbA10G2 of C. hominis and subgenotype IIaA15G2R1 of C. parvum were the most prevalent, although several other subgenotypes were identified. For Giardia, sequencing at the beta-giardin, triose phosphate isomerase (TPI) and glutamate dehydrogenase (GDH) genes revealed assemblage B as the most prevalent (74.4%) in human patients. A high degree of heterogeneity was found, especially on the beta-giardin gene, and to a lesser extent on the GDH gene. Furthermore, using a novel species-specific PCR based on the TPI gene, mixed infections with both assemblage A and B were detected in a large number (32.4%) of human patients, which might have important epidemiological implications.

The influence of matrix type, diurnal rhythm and sample collection and processing on the measurement of plasma beta-amyloid isoforms using the INNO-BIA plasma Abeta forms multiplex assay.

OBJECTIVE: The aim of the study was to determine the extent to which plasma matrix types, diurnal rhythm and sample collection and processing procedures contribute to overall variability of measurements with the INNO-BIA plasma Abeta forms assay. METHODS: Plasma samples from healthy volunteers were collected at BARC-CRI. Analyte concentrations from various plasma matrix types (EDTA, heparin, fluoride) were compared to serum after collection of blood in commercial plastic and glass tubes. Sample processing variables including time and temperature before and after centrifugation, centrifugal force and plasma dilution factor were also investigated. Diurnal variability in plasma Abeta isoforms was determined in 29 healthy volunteers by analysis of EDTA plasma specimens serially collected over 24 hours and stored frozen following oral administration of a placebo treatment. All plasma samples from a given individual and experiment were analyzed in a single analytical run. RESULTS: Highest Abeta levels were obtained using EDTA-plasma samples (in contrast to serum, heparin, citrate, or fluoride). Addition of aprotinin to EDTA plasma had no effect on Abeta peptide recovery. The elapsed time and temperature exposure, before and after sample processing affects the recovery of Abeta isoforms. Analyte recovery was not significantly affected by the presence of platelets in plasma samples. At the subject level, analysis of serially collected EDTA plasma specimens from healthy volunteers revealed no evidence of diurnal variation in any of the Abeta isoforms investigated and results from samples collected on a monthly basis showed only very limited intra-individual variation. CONCLUSIONS: Optimal recovery of Abeta peptides was obtained from blood drawn into EDTA tubes and processed within 4 h. Plasma that was refrigerated after separation and analysed within 4 h gave comparable results to samples immediately processed and frozen at -70 degrees C.

Recursive prediction of broiler growth response to feed intake by using a time-variant parameter estimation method.

The objective of this study was to explore whether time-variant parameter estimation procedures allow modeling and predicting the dynamic growth response of broiler chickens to feed intake in real time. A recursive linear model was used that estimated the model parameters every 24 h based on a fixed number of actual and past measurements (i.e., time window). Based on 48 datasets, it was concluded that the mean relative prediction error (MRPE) of the recursive linear modeling approach had a minimum for a window size of 5 d. Weight of the birds could be predicted during the growth process 3 to 7 d ahead with a mean relative prediction error of 5% or less. In comparison with the prediction results of three static empirical growth models (one linear and two nonlinear models), the recursive modeling technique had a similar accuracy to the nonlinear empirical models (MRPE of 1.4% to 2.3% vs. 1.1% to 2.8%), but it was less accurate for larger prediction horizons (2 to 7 d). The compact recursive linear model was more accurate than the static linear growth model for prediction horizons of one up to 4 d, depending on the feeding strategy. Since such recursive modeling approach allows the prediction of broiler growth without any prior knowledge of the system and takes into account the time-variant (nonlinear) nature of the growth process based on only a small window of measured information, it is suitable for real-time integration in process management.

The efficiency of nitrogen retention during compensatory growth of food-restricted broilers.

1. Two experiments were conducted to investigate the influence of compensatory growth, induced by early quantitative food restrictions, on the efficiency of nitrogen-retention in two lines of Ross broilers. 2. Birds were restricted to 80% of the ad libitum intake of the previous 24 h of the control group from d 4 to d 7. After the period of restrictions all birds were fed ad libitum. 3. In both trials, the final body weight of the restricted Ross 208(308) birds was similar or even higher than that of the control group. For the Ross 508 line, compensatory growth was substantial in the first trial, but non-existent in the second trial. In all cases, the mortality of restricted birds was lower than in control birds. 4. Not only environmental factors, but mainly chick quality, seemed to have a major influence on the capacity of the chickens to establish compensatory growth. 5. As compensatory growth was established, some improvement in N retention was induced. Although differences were not significant, they may be environmentally important. 6. It is concluded that a retardation of the early growth of fast growing broiler chickens can, in certain circumstances, reduce mortality and increase performance and N retention.

Early and temporary quantitative food restriction of broiler chickens. 1. Effects on performance characteristics, mortality and meat quality.

1. An experiment was conducted with broiler chickens to determine the effects of different early food restrictions, strain (Ross 508 and Hybro G) and sex on performance, mortality carcase composition and meat characteristics. 2. Birds were restricted to 80% or 90% of ad libitum intake for 4 d (80%-4 d-group and 90%-4 d-group, respectively) or 80% for 8 d (80%-8 d-group). All restrictions started on d 4. After the periods of restriction, all birds were fed ad libitum. 3. Only the 90%-4 d-group reached a final body weight not significantly different from, but lower than, the ad libitum group. The other restrictions were too severe to allow a sufficient 'catch-up'. 4. No significant differences in food conversion and total carcase fat content between groups were observed. Abdominal fat showed a tendency to increase due to the restrictions induced. 5. There was a slight trend towards a reduced mortality and of 'sudden death syndrome' but no clear effect of food restriction on number of chickens removed with leg problems. There was no significant decrease in uniformity of the flocks due to restriction. 6. The group 80%-8 d had a significant lower yield percentage. Cut-up parts and meat quality were not changed by restriction. Ross birds had a significantly higher proportion of breast meat than Hybro chickens. Meat of female chickens seemed to be paler than that of males, possibly because of the higher proportion of carcase fat. 7. Food restriction did not always give good results. However, a mild restriction (90% for 4 d) may offer some economic advantages over an ad libitum feeding regimen, mainly by reducing mortality.

Early and temporary quantitative food restriction of broiler chickens. 2. Effects on allometric growth and growth hormone secretion.

1. An experiment was conducted with male broiler chickens to investigate the effect of different early food restriction programmes on proportional weights and allometric growth coefficients of carcase parts and on pulsatile growth hormone secretion. 2. At 4 d of age the animals were restricted to 80% or 90% of the ad libitum intake for 4 d or 80% for 8 d. When the restriction was finished, all birds received ad libitum food again. 3. On d 1, 8, 11, 14, 21, 28, 35 and 42, from each group 8 birds were weighed, stunned and killed and the weights of the stomachs, liver, heart, sternum, right thigh, right drumstick, breast and abdominal fat pad were determined. On d 29, 30, 31, 32 serial blood samples of 2 birds from each group were taken to determine the plasma growth hormone (GH) content. 4. Only the most severe restriction resulted in a tendency for the stomachs to mature earlier and the thighs to mature later. No other significant effect on the allometric coefficients could be observed. 5. It is concluded that during the restriction the birds give priority to the development of the supply organs such as the stomach, which are more important during early development at the expense of the demand tissues like breast and thigh. 6. No significant differences concerning the GH secretory parameters could be observed.

Ideal amino acid profile and dietary lysine specification for broiler chickens of 20 to 40 days of age.

1. The aim of the study was to determine the ideal ratio of the essential amino acids lysine (Lys), methionine (Met), threonine (Thr), tryptophan (Trp), arginine (Arg), valine (Val) and isoleucine (Ile) and to assess the required dietary lysine concentration for optimum performance in broiler chickens of 2 commercial strains from 20 to 40 d of age. 2. An identical basal diet was used throughout all experiments. It consisted mainly of maize and soyabean meal and contained 172 g crude protein and 13.2 MJ AME(N) per kg. For each experiment, the basal diet was adequately supplemented with all essential amino acids except the one to be tested, which was supplemented in 6 graded concentrations in exchange for maize starch. One (Met, Trp, Arg, Val, Ile) or 2 (Lys, Thr) growth trials were conducted per amino acid tested and the response in weight gain, food: gain ratio, breast meat yield and abdominal fat were examined. 3. The ideal amino acid ratio relative to Lys (expressed as a percentage) was calculated to be 75% Met+Cys, 63% Thr, 19% Trp, 112% Arg, 71% Ile and 81% Val on a true faecal digestible basis when the data were subjected to broken-line regression analysis. From both lysine studies the concentration for optimum food: gain ratio was calculated, by exponential regression analysis, to be 11.5 g true faecal digestible lys per kg diet.

The bioefficacy of zinc bacitracin in practical diets for broilers and laying hens.

Two balance trials were conducted to examine the response in metabolizable energy and metabolizability of both fat and amino acids to graded levels of zinc bacitracin (ZnB; Albac registered trade name of Alpharma, Oslo, Norway) in practical broiler and layer diets varying in their nutrient density. Broiler diets were supplemented with either 0, 20, or 50 mg ZnB/kg and layer diets were supplemented with either 0, 50, or 100 mg ZnB/kg. Each experimental diet was fed to five replicates of four broiler chicks each or nine replicates of individually housed laying hens, respectively. All balance parameters were significantly influenced by nutrient density, age, and dietary ZnB level. No significant interactions between ZnB by nutrient density were found. Addition of ZnB resulted in a lower excreta:feed ratio and an improved N retention; there was a nearly linear relationship between these effects and dietary ZnB levels. Moreover, dietary MEn content was linearly enhanced by ZnB supplementation. As a consequence, the bioefficacy of ZnB can be expressed in terms of MEn units: the average MEn equivalency of ZnB was 2,080 and 1,184 Mcal/kg, for broiler chicks and laying hens, respectively.

Effect of dietary protein, essential and non-essential amino acids on the performance and carcase composition of male broiler chickens.

1. The present study was conducted to determine the possibility of using low-protein broiler diets supplemented with synthetic amino acids. The effects on performance, carcase composition and nitrogen retention were evaluated. 2. A starter diet was given, ad libitum, from 7 to 21 and a finisher diet from 21 to 42 d of age. Body weight, weight gain, food intake and food conversion (FC) were determined at 3 and 6 weeks of age. Abdominal fat deposition (AFD), carcase yield, carcase fat and protein and nitrogen retention were determined at 6 weeks of age. During the starter period chicks were given a 231 g/kg crude protein (CP) diet and a low protein diet supplemented with synthetic amino acid, a: to National Research Council recommendations, b: to the concentration of the control diet, and c: in agreement with the pattern of body composition. Glutamic acid and glycine were added to some diets as sources of non-essential amino acids (NEAA). All diets contained 12.62 MJ metabolisable energy (AMEn)/kg. The diets administered between 3 and 6 weeks were comparable to the starter diets, except that they contained more AMEn (12.85 MJ/kg) and less protein. 3. Performance equal to that of high protein controls was obtained with birds fed a low protein diet supplemented with synthetic essential and NEAA to the amounts in the control diet or based on the amino acid profile of body protein. This was not achieved with low protein diets supplemented with synthetic amino acids to the amounts recommended by NRC. 4. Without altering performances, the efficiency of protein utilisation of birds fed on low protein diets was superior to that of birds fed on the commercial control diet and their nitrogen excretion was reduced by 26%. The percentage carcase yield and protein was unaffected by the dietary regimen but carcase fat content and AFD increased as the protein content of the diet decreased. 5. These results show that it is possible to obtain the same performances with low protein diets supplemented with synthetic amino acids, using an ideal amino acid balance. However, low protein diets result in a higher carcase fat content.

Optimum isoleucine requirement of laying hens and the effect of age.

1. Medium weight laying hens were used for an assay to determine their isoleucine requirement between 26 and 36 weeks of age and again between 46 and 56 weeks of age. 2. Two isoleucine-limiting mixtures were formulated with similar amino acid profiles, one containing 198 g and the other 110 g crude protein per kg diet. These mixtures were blended to give a series of 11 diets with isoleucine contents ranging from 7.6 to 3.8 g/kg. The lowest protein diet was also fed with a supplement of L-isoleucine. Each of the 12 diets was given to 5 groups of 24 laying hens. 3. The daily isoleucine requirement of individual laying hens was estimated to be 9.48 mg/g egg output plus 44.47 mg/kg body weight per day for the 1st period and 12.11 mg/g egg output plus 6.86 mg/kg body weight per day for the 2nd period. Calculated optimum intakes of isoleucine for various ratios of cost of input to value of output are tabulated. For example, for a flock of medium weight hens producing an average of 50 g daily egg mass, the optimum isoleucine intake (mg/hen d) varied between 760 and 890 varying for ratios of costs to egg prices. 4. It is concluded that the isoleucine required per day does not decrease during the first laying year despite a decrease in rate of egg output.

Effect of ratio of unsaturated to saturated fatty acids of the dietary lipid fraction on utilization and metabolizable energy of added fats in young chicks.

Relationships between the ratio of unsaturated to saturated fatty acids (U:S) in the diet and the utilization and AME(n) of added fat were studied using the results of a number of previously reported experiments. Mathematical equations relating fat AME(n), fat utilization, and palmitic, oleic, and linoleic acid utilization to the U:S were calculated for young broiler chicks. Best fit regression equations for added fat utilization and fat AME(n) were exponential, showing fat utilization increased very steeply in the U:S range of 0 to 2.5, reaching a near asymptotical maximum at a U:S of 4 or more. Synergism between added fats, due to blending vegetable oils with animal fats or using basal diets with unsaturated lipid fractions, led to increased animal fat utilization values. The utilization of saturated fatty acids was especially affected by synergism, whereas utilization of unsaturated fatty acids was not influenced by changing U:S. The origin of effects of factors influencing fat utilization such as level of fat inclusion and basal diet composition, appeared to be through variation in degree of saturation of the total dietary lipid fraction. For young broilers, about 75% of the variation in fat utilization and AME(n) was due to differences in the chemical composition of the fat fraction.

Effect of plumage renewal after induced moulting on subsequent laying efficiency and persistence.

1. Brown egg layers and dwarf broiler breeder females were force-moulted by different diets. The relationship between the extent of feather replacement and subsequent laying performance was studied. Some brown hens were subjected to metabolic experiments in order to compare post-moult heat production in relation to moulting success. 2. The extent of moulting had a clear effect on the post-moult heat production, and the differences were still present after 6 months in the second year of laying. 3. The extent of feather renewal during moulting showed high and very significant rank correlations with efficiency of food utilisation during the subsequent laying cycle. These correlations were generally higher than those of other features of the moulting procedure (body-weight-loss, minimum weight, duration of pause in laying). 4. The long-term energetic implications of the extent of moulting play an important role in subsequent performances and the persistence of lay during the following year is related to the extent of feather replacement.

Effect of dietary fluoride on performances and bone characteristics of broilers and the influence of drying and defatting on bone-breaking strength.

A trial with broiler males, housed in cages, was conducted to determine the effect of (added) dietary fluoride at 0, 200, and 400 mg/kg on performance and bone characteristics and the influence of preconditioning (drying, defatting) on bone-breaking strength. The F administration resulted in a significantly (P less than .05) lower weight gain. Feed conversion, however, was not affected. Tibial ash deposition and ash-percentage increased significantly (P less than .05) at both dietary levels of added F. Broiler males fed supplemented F had a significantly (P less than .05) higher incidence of tibial dyschondroplastic plugs and epiphyseal bone with looser structure, as judged macroscopically. Tibial bone strength was significantly (P less than .05) affected not only by dietary F level, but also by preconditioning, resulting in a significant interaction. Administration of F had a significantly negative or positive effect on breaking strength, depending on whether the measurements were carried out on fresh bones or dried (defatted) bones, respectively. This diverging response of F on breaking strength offers a valid explanation for the contradictory results in the literature, demonstrating at the same time that F supplementation of feed or drinking water should be discontinued as a method to improve bone-breaking strength.

[Seromucous otitis and atopic allergy]. / L'otite séro-muqueuse et l'allergie atopique.

The various recent studies conducted are reviewed with the aim of establishing or refuting the hypothesis of a relation between immediate type I allergic reactions and seromucous otitis. Critical analysis of the different publications available is completed by an analysis of a personal series of 58 examinations of serum and secretory IgE levels in children 6 months to 11 years with seromucous otitis. Findings fail to support the hypothesis of type I allergy as a major, primary etiologic factor in seromucous otitis even though this affection can appear as a complication of an allergic diathesis.

The effect of different totals and ratios of dietary calcium and phosphorus on the performance and incidence of leg abnormalities of male and female broiler chickens.

A factorial experiment involving 1,404 day-old Shaver broiler chicks (702 of each sex) assessed the effects of total calcium (Ca) and available phosphorus (AP) and their ratio (Ca: AP) during the starter (0 to 21 days) and finisher (22 to 42 days) periods on general performance, tibia strength, tibia ash, Ca and P content of tibia ash, tibia dyschondroplasia, twisted legs, and total leg abnormalities. Nine starter and nine finisher diets were used with the percentage Ca and AP ranging from .98 to 1.47 and .39 to .67, respectively, for the starters and from 1.00 to 1.40 and .32 to .51, respectively, for finishers. In general, optimum weight gain, live body weight, feed conversion, tibia strength, tibia dry weight, and tibia ash were obtained when the highest Ca + P was fed, but lower Ca:AP ratios were also effective for some traits. Tibial dyschondroplasia (TD) and total leg abnormalities, however, were highest when these diets were fed. The results indicate that the ratio of Ca:AP in the diet is a determining factor in causing TD in broiler chickens. As the ratio of Ca:AP in the diets widened in response to increased Ca or decreased P, the incidence of TD and total leg abnormalities decreased (P less than .05).

Screening of sera and tumor extracts of cancer patients using a monoclonal antibody directed against human placental alkaline phosphatase.

A sensitive endogenous enzyme immunoassay involving an anti-human placental alkaline phosphatase (PLAP) monoclonal antibody was used in the screening of sera and tumor extracts of patients with various types of cancer. In sera of breast cancer patients an incidence of 5.2% was recorded. This value rose to 43% when tumor extracts were analyzed. For lung and bronchial cancers we found 11.2% seropositive patients. On several occasions a good correlation was observed between the PLAP determinations and the histopathological staging of tumor tissue.

Atopic allergy and otitis media with effusion.

To investigate the possible role of type 1 allergy in OME, the immunoglobulin E (IgE) content was determined in 58 middle ear effusions and matched sera, obtained from children with otitis media with effusion (OME). The IgE levels were assayed for IgE by the Phadebas paper radio immunosorbent test (PRIST). Eight cases (14%) showed elevated serum IgE levels, such that an atopic disorder was very likely. However, in nearly all cases the effusion/serum ratio (E/S) was less than one, showing a higher IgE level in the serum than in the effusion. A modified PAP technique for determining surface IgE on mast cells is presented. Positive results were obtained on nasal mucosa specimens in atopic patients with OME but further research on middle ear mucosa in OME is needed. Our results fail to support the concept of type 1 allergy as a major causative factor in OME.

Efficacy of heat-inactivated hepatitis B vaccine in haemodialysis patients and staff. Double-blind placebo-controlled trial.

The efficacy of a heat-inactivated hepatitis B vaccine, 3 micrograms of surface antigen (HBsAg), given at 0, 1, 2, and 5 months, was evaluated in 401 haemodialysis patients in 18 centres by a placebo-controlled, double-blind, randomised trial. The attack-rate of hepatitis B virus (HBV) infections in the control group was 18% over 435 days. The protective efficacy rate of the vaccine was 78% against all HBV infections in the entire study (p = 0.00016), and 94% against HBsAg-positive hepatitis more than 3 months after day 0. Those patients in whom HBV developed showed no evidence of vaccine-acquired anti-HBs. Among 152 similarly randomised staff members receiving three monthly injections, all 5 HBsAg-positive infections occurred in the placebo group (p = 0.022). The vaccine induced anti-HBs in 88% of the patients and 100% of the staff. Immediately after the fourth injection, anti-HBs levels were as high in responding patients as in staff. There were no serious side effects. In the four-dose schedule the vaccine provides dialysis patients with protection of the same order as that given by other hepatitis B vaccines to normal subjects.