Formulation and Optimization of Nonionic Surfactants Emulsified Nimesulide-Loaded PLGA-Based Nanoparticles by Design of Experiments

This investigation aimed to develop nimesulide (NMS)-loaded poly(lactic-co-glycolic acid) (PLGA)-based nanoparticulate formulations as a biodegradable polymeric drug carrier to treat rheumatoid arthritis. Polymeric nanoparticles (NPs) were prepared with two different nonionic surfactants, vitamin E d-α-tocopheryl polyethylene glycol 1000 succinate (vitamin E TPGS) and poly(vinyl alcohol) (PVA), using an ultrasonication solvent evaporation technique. Nine batches were formulated for each surfactant using a 3² factorial design for optimal concentration of the emulsifying agents, 0.03–0.09% for vitamin E TPGS and 2–4% for PVA. The surfactant percentage and the drug/polymer ratio (1:10, 1:15, 1:20) of the NMS-loaded NPs were investigated based on four responses: encapsulation efficiency, particle size, the polydispersity index, and the surface charge. The response surface plots and linearity curves indicated a relationship between the experiment’s responses and a set of independent variables. The NPs produced with both surfactants exhibited a negative surface charge, and scanning electron micrographs revealed that all of the NPs were spherical in shape. A narrower size distribution and higher drug loadings were achieved in PVA-emulsified PLGA NPs than in the vitamin E TPGS emulsified. Decreasing amounts of both nonionic surfactants resulted in a reduction in the emulsion’s viscosity, which led to a decrease in the particle size of NPs. According to the ANOVA results obtained in this present research, vitamin E TPGS exhibited the best correlation between the independent variables, namely drug/polymer ratio and the surfactant percentage, and the dependent variables (encapsulation efficiency R² = 0.9603, particle size R² = 0.9965, size distribution R² = 0.9899, and surface charge R² = 0.8969) compared with PVA.KEY WORDS: ANOVA, factorial design, nanoparticles, nimesulide, PLGA, PVA, vitamin E TPGS     

Atomic force microscopy characterization of silver nanoparticles interactions with marine diatom cells and extracellular polymeric substance

This study highlights the capacity of atomic force microscopy (AFM) for investigating nanoparticle (NP) algal cell interaction with a subnanometer resolution. We designed a set of AFM experiments to characterize NP size, shape, and structure to visualize changes in the cell morphology induced by NPs and to characterize NP interaction with the extracellular polymeric substance (EPS). Samples for AFM imaging were prepared using the same protocol-drop deposition on mica and imaged in air. Here we address the interactions of Ag NPs with ubiquitous, lightly silicified marine diatoms Cylindrotheca fusiformis and Cylindrotheca closterium and their EPS. In natural seawater used throughout this study, the single Ag NPs adopted truncated tetrahedron morphology with particle heights of 10, 20, 30, and 40 nm. This size class Ag NPs penetrates the cell wall through the valve region built of silica NPs embedded in organic matrix. The Ag NPs cause a local damage inside the cell without disintegration of the cell wall. The EPS production has been shown to increase as a feedback response to Ag NP exposure and may contribute to detoxification mechanisms. Imaging EPS at high resolution revealed the incorporation of Ag NPs and their aggregates into the EPS-gel matrix, proving their detoxifying capacity.     

Design,Optimization, and Evaluation of Lurasidone Hydrochloride Nanocrystals

The present investigation was carried out to design, optimize, and evaluate lurasidone hydrochloride nanocrystals for improving its solubility and dissolution characteristics. Nanocrystals were prepared by media milling technique using zirconium oxide beads with 0.1 mm diameter. Various stabilizers, viz. poloxamer 188, PVP K30, SLS, HPMC E15, and PVP S 630 D, were evaluated to stabilize the nanocrystals. The Pareto chart obtained through Plackett-Burman screening design revealed that HPMC E 15 showed the highest standardized effect (p value <0.05) on percent dissolution efficiency at 2 min. In subsequent studies, a 3² factorial design was employed to quantify the effect of two independent variables, namely amount of stabilizer and milling time on predetermined response variables mean particle size, saturation solubility, and percent dissolution efficiency at 2 min. Statistical analysis of the factorial design revealed that all predetermined response variables were significantly dependent (p value <0.05) on the independent variables. The observed response of the optimized batch prepared as per the desirability function was in close agreement with predicted response, and mathematical model generated was validated. The optimized batch was lyophilized, and X-ray powder diffraction studies indicated that there was no substantial change in crystallinity of the drug. The optimized formulation showed mean particle size of 228 nm and released almost all the drug within first 5 min. Since the crystallinity of the drug is maintained, improvement in saturation solubility and dissolution efficiency could be attributed to decrease in mean particle size of the drug.     

Adjusting the number of spermatozoa in mini-straws by determination of the operative volume of bovine semen

The importance of the number of sperm per insemination on fertility has been well demonstrated in cattle. This number is usually calculated from the concentration in the extended semen and a theoretical value for the operative volume of semen delivered during insemination. The objective of this experiment was to investigate the usefulness of the measurement of the delivered volume of semen when estimating sperm numbers from frozen-thawed mini-straws, by comparing the results obtained with an analytical balance to the theoretical volume. The density of semen extended with Biociphos Plus and Triladyl was determined to be 1.033 g/ml using the gamma sphere method. This value was used to convert semen weight into operative volume. The effect of semen temperature at the time of weighing (37 degrees C versus 20 degrees C) was investigated on six semen batches, two technicians measuring the operative volume of 50 straws for each combination of temperature and semen batch (a total of 1200 weighings). The temperature effect was found to be insignificant, which allowed warm semen to be weighed before motility was assessed during routine quality control. The operative volume was then measured in straws routinely produced at 17 bovine Al centers (12-105 semen batches per center, mostly three straws from each batch, a total of 1912 measurements). The observed volumes were normally distributed around 198.7 microl, 98% measuring between 180 and 210 microl. The operative volume was significantly different among centers (from 192 to 205 microl, P < 0.0001) and among batches within centers (P < 0.0001). The S.D. among straws within batches was 3.4 microl. Some centers showed high variability in straw volume whereas others were more consistent. Determination of the operative volume of frozen-thawed mini-straws by weighing the delivered contents is an accurate method for estimation of the number of sperm per dose.     

Influence of Plasmonic Silver Nanoparticles on Fluorescence Quenching of 1,4-dihydroxy-3-methylanthracene-9,10-dione

Optical absorption and fluorescence emission techniques were employed to investigate the size effects of silver nanoparticles (Ag NPs) on 1,4-dihydroxy-3-methylanthracene-9,10-dione (DHMAD). Silver nanoparticles of different sizes were prepared by Creighton method under microwave irradiation. The prepared Ag NPs show the surface plasmon band around 400 nm. Fluorescence quenching of DHMAD by Ag NPs was found to increase with an increase in the size of Ag NPs. The fluorescence quenching is explained by resonant energy transfer mechanism between DHMAD and Ag NPs, orientation of DHMAD on silver nanoparticles through chemisorptions. The Stern–Volmer quenching constant and Benesi–Hildebrand association constant for the above system were calculated. DFT calculations were also performed to study the ground and excited state behavior of DHMAD and DHMAD + Ag system.     

Preparation, Sensitivity, and Specificity of Limulus Lysate for Endotoxin Assay

Limulus amoebocyte lysate was prepared from a total of 180 crabs during 1971 and 1972 by using a slightly modified lysate preparation procedure. Marked variability of lysate potency was noted both years. In addition, lysate quality appeared diminished in 1972 as compared with 1971. Different lysate batches were evaluated for potency by using a variety of endotoxin preparations. Variations in batch potencies were observed, but little variation in reactivity among different endotoxin preparations was noted. Use of potent lysate batches allowed detection of endotoxin concentrations as low as 100 pg/ml. No endotoxinlike activity was observed from 11 different strains of yeast by use of the Limulus assay.     

Batchwise assessment of porcine embryos for cryotolerance

The viability or developmental ability of porcine embryos after slow-freezing and thawing differs depending on the embryonic stage or the batch, which is defined as a group of embryos obtained from one donor at one time. We froze porcine blastocysts in batches and assessed their cryotolerance by using two expanded blastocysts (EBs) as samples to predict the developmental potential of other blastocysts from the same batch at different stages. Two EBs from the same batch that had been separately frozen were thawed and cultured in vitro for 48 h to examine their in vitro ability to develop to the hatched blastocyst stage. Thereafter, each batch was assigned to Grade A, B, or C according to the viability of the two EBs, i.e., 100% viability (2/2: number of hatched blastocysts/number of cultured EBs) was Grade A; 50% (1/2) was Grade B; and 0% (0/2) was Grade C. The viability of EBs after freeze-thawing and in vitro culture varied depending on the batch and was lower (31.0+/-10.2%, mean+/-S.E.M.; P<0.01) than that of unfrozen controls (96.8+/-2.3%). The viability of frozen-thawed hatched blastocysts (HBs) did not differ among the graded batches, but the blastocyst diameter decreased (from 409 to 326 microm) as the batch grade decreased (from A to C). When both EBs and HBs from batches of the same grade were transferred to recipients (average 11.7 EBs and 16.0 HBs per recipient), the rate of pregnancy and farrowing in recipients decreased (from 77.8% to 0%) and the number of piglets obtained decreased (from 15.3 to 0) as the batch grade decreased. However, when not only frozen-thawed EBs from Grade B or C batches, but also four helper embryos at the morula to early blastocyst stage (which were expected to support the pregnancy) were transferred, the number of piglets generated was higher from EBs from Grade B batches (16.0) than from EBs from Grade C batches (0.0). When frozen-thawed HBs and helper embryos were transferred, the number of piglets generated was higher from HBs from Grade B batches (12.7) than that from HBs from Grade C batches (1.9). After slow-freezing of porcine blastocysts, their rate of survival to the piglet stage differs batchwise, and in vitro viability assessment of sample EBs after freezing and thawing may help in assessing the post-freezing and post-thawing developmental potential of other blastocysts at different stages from the same batch.     

Characterization of titanium dioxide nanoparticles imprinted for tyrosine by flow field-flow fractionation and spectrofluorimetric analysis

Films based on TiO₂ nanoparticles (NPs) have been successfully used as sensing elements in chemical sensors. TiO₂ colloidal suspensions can be obtained by spontaneous hydrolysis in acidic solutions of Ti(IV) compounds. The obtained TiO₂ NPs can be employed to build up nanostructured films. With the purpose of preparing TiO₂-based nanostructured, imprinted materials as sensing elements for piezoelectric sensors, we obtained TiO₂ NP dispersions by hydrolyzing potassium titanyl oxalate in the presence of a target analyte (tyrosine). Since morphological properties of the synthesized NPs are known to influence the nanostructured film characteristics, an analytical strategy to characterize such colloidal systems can combine a size-based separation method with spectroscopic analysis to correlate the particle size distribution (PSD) with the particle-target interaction properties able to determine the sensing efficiency.In this work, we present the characterization of colloidal tyrosine-TiO₂ NP systems by flow field-flow fractionation (FlFFF) with online, UV/Vis absorption detection and offline fluorescence analysis. FlFFF eliminates the possible contribution of free tyrosine to the absorption and fluorescence properties of the NPs. FlFFF also fractionates NPs on a size basis. Particle size distribution (PSD) profiles of the fractionated NPs are then obtained by conversion of the multi-wavelength UV/Vis fractograms. Size of the fractionated NPs is finally related to fluorescence properties of the collected NPs fractions. Good correlation between the fluorescence intensity, which is proportional to the tyrosine uptake, and the FlFFF-based, NP mass-size frequency distribution finally confirms the existence of tyrosine-TiO₂ NP interaction.     

Modified Nanoprecipitation Method for Preparation of Cytarabine-Loaded PLGA Nanoparticles

The present investigation was aimed at developing cytarabine-loaded poly(lactide-coglycolide) (PLGA)-based biodegradable nanoparticles by a modified nanoprecipitation which would have sustained release of the drug. Nine batches were prepared as per 3² factorial design to optimize volume of the co-solvent (0.22–0.37 ml) and volume of non-solvent (1.7–3.0 ml). A second 3² factorial design was used for optimization of drug: polymer ratio (1:5) and stirring time (30 min) based on the two responses, mean particle size (125 ± 2.5 nm), and percentage entrapment efficiency (21.8 ± 2.0%) of the Cyt-PLGA nanoparticles. Optimized formulation showed a zeta potential of −29.7 mV indicating good stability; 50% w/w of sucrose in Cyt-PLGA NP was added successfully as cryoprotectant during lyophilization for freeze-dried NPs and showed good dispersibility with minimum increase in their mean particle sizes. The DSC thermograms concluded that in the prepared PLGA NP, the drug was present in the amorphous phase and may have been homogeneously dispersed in the PLGA matrix. In vitro drug release from the pure drug was complete within 2 h, but was sustained up to 24 h from PLGA nanoparticles with Fickian diffusion. Stability studies showed that the developed PLGA NPs should be stored in the freeze-dried state at 2–8°C where they would remain stable in terms of both mean particle size and drug content for 2 months.     

Long-term effects of CuO nanoparticles on the surface physicochemical properties of biofilms in a sequencing batch biofilm reactor

In this study, we examined the long-term effects of copper oxide nanoparticles (CuO NPs) on the production and properties of EPS and the resulting variations in surface physicochemical characteristics of biofilms in a sequencing batch biofilm reactor. After exposure to 50 mg/L CuO NPs for 45 days, the protein (PRO) and polysaccharide (PS) contents in loosely bound EPS (LB-EPS) decreased as the production of LB-EPS decreased from 34.4 to 30 mg TOC/g EPS. However, the production of tightly bound EPS (TB-EPS) increased by 16.47 % as the PRO and PS contents increased. The content of humic-like substances (HS) increased significantly, becoming the predominant constituent in EPS with the presence of 50 mg/L CuO NPs. Furthermore, the results of three-dimensional excitation-emission fluorescence spectra confirmed the various changes in terms of the LB-EPS and TB-EPS contents after exposure to CuO NPs. Fourier transform infrared spectroscopy showed that the –OH and –NH₂ groups of proteins in EPS were involved in the reaction with CuO NPs. Moreover, the chronic exposure to CuO NPs induced a negative impact on the flocculating efficiency of EPS and on the hydrophobicity and aggregation ability of microbial cells. The PRO/PS ratios of different EPS fractions were consistent with their hydrophobicities (R ² >0.98) and bioflocculating efficiencies (R ² >0.95); however, there was no correlation with aggregation ability. Additionally, the presence of bovine serum albumin (BSA) prevented the physical contact between CuO NPs and EPS as a result of NP aggregation and electrostatic repulsion.     

Susceptibility to an inoculum of infectious hypodermal and haematopoietic necrosis virus (IHHNV) in three batches of whiteleg shrimp Litopenaeus vannamei (Boone, 1931)

The present study evaluated the susceptibility of three different batches of whiteleg shrimp Litopenaeus vannamei from Mexico to an inoculum of infectious hypodermal and haematopoietic necrosis virus (IHHNV). Each of the three shrimp batches came from a different hatchery. Because of their origin, it was possible that the genetic makeup of these batches was different among each other. The three batches tested showed differences in IHHNV susceptibility. Here, susceptibility is defined as the capacity of the host to become infected, and it can be measured by the infectivity titer. Susceptibility to IHHNV was observed in decreasing order in shrimp from batch 1 (hatchery from El Rosario, Sinaloa), batch 3 (hatchery from Nayarit) and batch 2 (hatchery from El Walamo, Sinaloa), respectively. The largest susceptibility difference between batches was 5012 times, and that between early and late juveniles from the same batch was 25 times. These results indicate that within a species, susceptibility to a pathogen such as IHHNV can have large differences. Susceptibility to pathogens is an important trait to consider before performing studies on pathogenesis. It may influence virological parameters such as speed of replication, pathogenicity and virus titer. In order to evaluate the potential use of IHHNV as a natural control agent against white spot syndrome virus (WSSV), it is necessary to know host susceptibility and the kinetics of IHHNV infection. These features can help to determine the conditions in which IHHNV could be used as antagonist in a WSSV infection.     

Phylogenetic cross-reactivities of monoclonal antibodies produced against rat neurophysin

Previously described mouse monoclonal antibodies against rat neurophysins [Ben-Barak, Y., et al. (1985); Whitnall, M. H., et al. (1985)] were studied here for their cross-reactivities to neurophysins (NPs) from other vertebrate species. Posterior pituitary extracts from various mammals (rat, mouse, cow, human) and lower vertebrates (frog, ratfish) were studied. The monoclonal antibodies displayed several distinct patterns of cross-reactivity to the various species, indicating that the epitopes which they recognized were different. PS 67 bound strongly to rat pituitary extract in solid-phase radioimmunoassay (RIA) but showed no cross-reactivity with extracts from any of the other species tested, including the mouse. PS 36 cross-reacted with mouse and frog extracts but showed almost no cross-reactivity with cow and none to ratfish extracts. PS 41 cross-reacted with mouse, cow, and frog extracts. PS 45 was the most cross-reactive antibody and recognized an antigen in extracts from mouse, cow, frog, and ratfish pituitaries. Electrophoresis of proteins extracted from posterior pituitaries, followed by immunoblot staining with either PS 36 or PS 45, demonstrated that the NP-like molecules within each species are heterogeneous, i.e., more than two bands stained in each species. The frog NP stained by PS 45 was about twice the molecular weight of the mammalian NPs. The possible valve of the PS 45 antibody for future molecular cloning experiments on the arginine vasotocin precursor in lower vertebrates is discussed.     

Cytotoxicity and Genotoxicity in Human Embryonic Kidney Cells Exposed to Surface Modify Chitosan Nanoparticles Loaded with Curcumin

The rapid progress in the development and scientific investments of modified nanoparticles are due to their owed activity to various diseased conditions for which they are prepared. But the toxicity which they cause cannot be overlooked. The present study demonstrates the development of phosphatidylserine (PS)-coated chitosan (CS) nanoparticles (NPs) loaded with curcumin (CU), which was then investigated against human embryonic kidney cells (HEK 293) for its cytotoxic and genotoxic effect in rats. The CU-loaded CNPs (CNPs-CU) have been prepared by ionic gelation method, later which were grafted with PS. CNPs-CU and PS-CNPs-CU have been evaluated for their size, poly dispersity index, amount of drug entrapped, and in vitro CU release. CNPs-CU has an average size 167.6?±?3.53 nm and polydispersity index (PDI) 0.115?±?0.014, whereas PS-CNPs-CU shows average size 220?±?3.67 nm and PDI 0.148?±?0.019. Surface morphology of prepared NPs was confirmed by high-resolution transmission electron microscopy (HR-TEM). There was no major difference in cell viability between PS-CNPs-CU and CNPs-CU when they were exposed to HEK 293 cells at all equivalent concentrations. A series of genotoxic studies were conducted, which revealed the non-genotoxicity potential of the developed complexes. These results demonstrated that PS-CNPs-CU may be useful as potential delivery system.     

Optimization of the formulation for a candidate lyophilised tetanus toxoid reference preparation

Tetanus toxoid is a vital primary reference material used for standardization of assays required to establish the antigenic purity of tetanus toxoid for vaccine production. Several formulations were assessed and ampouled fills of each formulation lyophilised. The relative Lf content determined by Ramon flocculation, SRD, and ELISA assays was measured. The stability of the tetanus toxoid activity in each formulation was assessed by accelerated degradation studies. Formulations containing glycine were not suitable in flocculation tests but both sorbitol and trehalose formulations were. The trehalose/sodium chloride formulation had a good appearance, showed good activity in all assays and maintained its activity best under stress conditions. This formulation has been applied to a large scale batch of ampoules prepared as a WHO candidate replacement standard, evaluated in a collaborative study and accepted as a replacement WHO IS for use in flocculation test (WHO ECBS, October 2007, ref no BS/07.2061). The stability of this formulation was also excellent for the large scale batch. The benefits of using thermal analysis and freeze drying microscopy coupled with small scale lyophilisation trials in order to screen formulations for the preparation of batches of biological reference materials are demonstrated.     

Glycol chitosan/heparin immobilized iron oxide nanoparticles with a tumor-targeting characteristic for magnetic resonance imaging

We described the preparation of the glycol chitosan/heparin immobilized iron oxide nanoparticles (composite NPs) as a magnetic resonance imaging agent with a tumor-targeting characteristic. The iron oxide nanoseeds used clinically as a magnetic resonance imaging agent were immobilized into the glycol chitosan/heparin network to form the composite NPs. To induce the ionic interaction between the iron oxide nanoseeds and glycol chitosan, gold was deposited on the surface of iron oxide nanoseeds. After the immobilization of gold-deposited iron oxide NPs into the glycol chitosan network, the NPs were stabilized with heparin based on the ionic interaction between cationic glycol chitosan and anionic heparin. FE-SEM (field emission-scanning electron microscopy) and a particle size analyzer were used to observe the formation of the stabilized composite NPs, and a Jobin-Yvon Ultima-C inductively coupled plasma-atomic emission spectrometer (ICP-AES) was used to measure the contents (%) of formed iron oxide nanoseeds as a function of reaction temperature and formed gold deposited on the iron oxide nanoparticles. We also evaluated the time-dependent excretion profile, in vivo biodistribution, circulation time, and tumor-targeting ability of the composite NPs using a noninvasive NIR fluorescence imaging technology. To observe the MRI contrast characteristic, the composite NPs were injected into the tail veins of tumor-bearing mice to demonstrate their selective tumoral distribution. The MR images were collected with conventional T(2)-weighted spin echo acquisition parameters.     

Subtle membrane changes in cryopreserved bull semen in relation with sperm viability,chromatin structure,and field fertility

This study investigated the use of annexin-V/PI assay to assess sub lethal changes in bull spermatozoa post-thawing, and to further relate these changes to results obtained by fluorometric assessment of sperm viability and sperm chromatin structure assay (SCSA), as well as field fertility (as 56-day non-return rates, 56-day NRR) after AI. Frozen-thawed semen samples were obtained from 18 Swedish Red and White bulls (one to three semen batches/bull) and fertility data was based on 6900 inseminations. The annexin-V/PI assay revealed that post-thaw semen samples contained on average 41.8+/-7.5% annexin-V-positive cells. Most of the annexin-V-positive cells were dying cells, i.e. also PI-positive. The incidence of annexin-V-positive cells was negatively related (r=-0.59, P<0.01) to the percentage of viable cells, as detected by fluorometry. The incidence of annexin-V-positive spermatozoa significantly correlated to the SCSA variable xalphat (r=0.53, P<0.05). The incidence of annexin-V-negative, dead cells was the only annexin-V/PI assay variable that correlated significantly with fertility both at batch (r=-0.40, P<0.05), and bull (r=-0.56, P<0.05) levels. Among sperm viability variables, subjectively assessed sperm motility (r=0.52-0.59, P<0.01), CASA-assessed sperm motility (r=0.43-0.61, P<0.05), and the incidence of live spermatozoa, expressed as total numbers (r=0.39-0.54, P<0.05), or percentage values (r=0.68-0.68, P<0.01), correlated significantly with field fertility both at batch, and bull levels. Among the SCSA variables, only the COMP alphat correlated significantly (r=0.33-0.51, P<0.05) with fertility results. The results indicate a certain proportion of bull spermatozoa express PS on their surface after thawing, e.g. they have altered membrane function, and that the incidence of such cells is inversely correlated to sperm viability, and positively correlated to abnormal sperm chromatin condensation since they eventually undergo necrosis.     

Monitoring of a sequencing batch reactor using adaptive multiblock principal component analysis

Multiway principal component analysis (MPCA) for the analysis and monitoring of batch processes has recently been proposed. Although MPCA has found wide applications in batch process monitoring, it assumes that future batches behave in the same way as those used for model identification. In this study, a new monitoring algorithm, adaptive multiblock MPCA, is developed. The method overcomes the problem of changing process conditions by updating the covariance structure recursively. A historical set of operational data of a multiphase batch process was divided into local blocks in such a way that the variables from one phase of a batch run could be blocked in the corresponding blocks. This approach has significant benefits because the latent variable structure can change for each phase during the batch operation. The adaptive multiblock model also allows for easier fault detection and isolation by looking at the relationship between blocks and at smaller meaningful block models, and it therefore helps in the diagnosis of the disturbance. The proposed adaptive multiblock monitoring method is successfully applied to a sequencing batch reactor for biological wastewater treatment.     

Role of batch depletion of broiler houses on the occurrence of Campylobacter spp. in chicken flocks

AIMS: The effect of batch depletion of broiler houses for campylobacter occurrence in broiler flocks was estimated in 10 flocks, each comprising a separate female and male batch. METHODS AND RESULTS: The chicks were sampled first by cloacal swabs in the broiler houses before the start of the depopulation and secondly, on arrival at the abattoir. Females were slaughtered at 5 weeks of age, males at 6 weeks. The number of campylobacter-positive batches increased from five to seven female batches, and from five to 10 male batches, between the two sampling rounds. CONCLUSION: It is concluded that batch depletion of broiler houses increased the prevalence of Campylobacter spp.-infected broilers in the flocks, that the introduction occurred when catching the first batch, and that campylobacter spreads through the entire flock within a week. SIGNIFICANCE AND IMPACT OF THE STUDY: The results from this study emphasize the need to manage depopulation of broiler houses as quickly as possible and in one batch only.