Cultivation and qPCR Detection of Pathogenic and Antibiotic-Resistant Bacterial Establishment in Naive Broiler Houses.

Conventional commercial broiler production involves the rearing of more than 20,000 broilers in a single confined space for approximately 6.5 wk. This environment is known for harboring pathogens and antibiotic-resistant bacteria, but studies have focused on previously established houses with mature litter microbial populations. In the current study, a set of three naive houses were followed from inception through 11 broiler flocks and monitored for ambient climatic conditions, bacterial pathogens, and antibiotic resistance. Within the first 3 wk of the first flock cycle, 100% of litter samples were positive for and , whereas was cultivation negative but PCR positive. Antibiotic resistance genes were ubiquitously distributed throughout the litter within the first flock, approaching 10 to 10 genomic units g. Preflock litter levels were approximately 10 CFU g for heterotrophic plate count bacteria, whereas midflock levels were >10 colony forming units (CFU) g; other indicators demonstrated similar increases. The influence of intrahouse sample location was minor. In all likelihood, given that preflock levels were negative for pathogens and antibiotic resistance genes and 4 to 5 Log lower than flock levels for indicators, incoming birds most likely provided the colonizing microbiome, although other sources were not ruled out. Most bacterial groups experienced a cyclical pattern of litter contamination seen in other studies, whereas microbial stabilization required approximately four flocks. This study represents a first-of-its-kind view into the time required for bacterial pathogens and antibiotic resistance to colonize and establish in naive broiler houses.

Using broiler litter and swine manure lagoon effluent in sawdust-based swine mortality composts: Effects on nutrients, bacteria, and gaseous emissions.

Disposition of mortalities challenges confined animal feeding operations (CAFOs), especially sow (farrowing) farms, which experience mortalities daily. Regulations and transportation costs may preclude incineration, landfill burial, and rendering; therefore, swine CAFOs in Mississippi in the Mid-South U.S. often compost mortalities. In this study, a farm-standard composting mix of sawdust (S) and water (W) was compared with mixes where N was supplied by broiler litter (L) and water was replaced with swine lagoon effluent (E). The objective was to assess the effects of these manure byproducts: 1) on nutrients and bacteria in composts destined for land application; and 2) on emissions of ammonia and greenhouse gases. Three replications of four mixes (SW, SLW, SE, SLE) were compared in microcosms comprising modified plastic recycling bins. The experiment was repeated three times in different seasons in one year. Mixes were compared for differences in temperature, water content, nutrients (C, N, P, K, Ca, Mg, Na, Mn, Fe, Cu, Zn), bacteria (Gram-, Gram+, Clostridium perfringens, Salmonella, Listeria, Escherichia coli), and emissions (NH3, CO2, CH4, N2O). Litter addition increased composting temperatures initially and after aerations; increased nutrient concentrations, except C, in start mixes and all except C and N, in finish mixes; increased Gram+ bacteria, Salmonella, and E. coli in start mixes, but only Gram+s in finish mixes; and increased emissions. Effluent addition increased early composting temperatures; had no effect on nutrients or bacteria, except increased C. perfringens in start, but not finish mixes; and had no effect on emissions. Nutrients in finish composts did not differ among mixes for N (average 3.3%), but litter composts had more P and K, and lower N:P than composts without litter. Improving mortality composting is of global importance as increasing livestock populations and intensive animal production systems require practical, safe, environmentally sound disposal of carcasses.

Ammonia and nitrous oxide emissions from a commercial broiler house.

Complex variation in gas emissions from animal facilities has been shown in recent research reports. Uncertainties in these emission estimates are driving research activities concerning different animal species across the globe. Greenhouse gas (NO and CO) and NH concentrations were measured in a modern, tunnel-ventilated, commercial broiler house in Mississippi during five flocks (spanning approximately 1 yr). These were flocks 9 through 13 on reused pine shavings litter, representing litter reuse beyond 2 yr. Gas concentrations obtained from a photoacoustic multigas analyzer were coupled with ventilation measurements of air flow through the house to develop NH and NO emission rates. Ammonia emission during a flock (43 d) averaged approximately 14.8 ± 9.8 kg d in the commercial house (equivalent to 23.5 g bird marketed or 0.54 g bird d). Nitrous oxide emission averaged 2.3 ± 1.7 kg d in the house (equivalent to 3.64 g bird marketed or 0.085 g bird d). Emission rates increased with time from Day 1 to Day 43 and reached average values on Day 23 and 24 for NH and NO. Even with extended litter reuse, estimates of NH emissions from the broiler house agree well with recently published research that reused litter in eight or fewer flocks. This is important information for farmers who may not be able to afford to replace the litter with fresh bedding material annually.

Broiler litter ammonia emissions near sidewalls, feeders, and waterers.

Ammonia (NH3) volatilized from broiler litter diminishes indoor air quality, which can potentially decrease bird productivity. Emissions of NH3 exhausted from broiler houses pose environmental concerns for ecosystem biodiversity, aquatic nutrient enrichment, and particulate formation in the atmosphere. Research was conducted sampling litter (rice hull base) in 3 tunnel-ventilated commercial broiler houses during wk 3 (mid-growout) of 6 flocks. The purpose was to assess NH3 generated near the sidewalls, waterers, and feeders. Litter samples (100 g) were placed in chambers receiving constant air flow. Boric acid (H3BO3) titration each 24 h for 4 d was used to determine NH3 volatilized from the samples. Litter located near waterers emitted the most cumulative NH3 (approximately 12.3 mg of N•kg of litter(-1)•h(-1)) with less NH3 associated with feeders and sidewalls (2.9 to 7.6 mg of N•kg of litter(-1)•h(-1)). Moisture content of litter samples was greatest at waterers (45%) followed by sidewalls (26%) and feeders (20%). In addition, litter pH at the sidewalls and feeders could be predicted by linear equations associated with the number of flocks on the litter. At the waterers, litter pH was differentiated based on the half of house where higher litter pH existed in the nonbrood half (8.55 vs. 8.13). The results indicate that controlling NH3 near watering lines to a level consistent with feeding lines and near the house wall could reduce NH3 generated by 38 to 77%. These findings support efforts for NH3 control at mid-growout, especially considering zone litter treatments near waterers and appropriate attention to waterer management.

The effect of poultry manure application rate and AlCl(3) treatment on bacterial fecal indicators in runoff.

Increasing costs associated with inorganic fertilizer have led to widespread use of broiler litter. Proper land application, typically limiting nutrient loss, is essential to protect surface water. This study was designed to evaluate litter-borne microbial runoff (heterotrophic plate count bacteria, staphylococci, Escherichia coli, enterococci, and Clostridium perfringens) while applying typical nutrient-control methods. Field studies were conducted in which plots with high and low litter rates, inorganic fertilizer, AlCl(3)-treated litter, and controls were rained on five times using a rain generator. Overall, microbial runoff from poultry litter applied plots was consistently greater (2-5 log(10) plot(-1)) than controls. No appreciable effect on microbial runoff was noted from variable litter application rate or AlCl(3) treatments, though rain event, not time, significantly affected runoff load. C. perfringens and staphylococci runoff were consistently associated with poultry litter application, during early rain events, while other indicators were unreliable. Large microbial runoff pulses were observed, ranging from 10(2) to 10(10) CFU plot(-1); however, only a small fraction of litter-borne microbes were recoverable in runoff. This study indicated that microbial runoff from litter-applied plots can be substantial, and that methods intended to reduce nutrient losses do not necessarily reduce microbial runoff.

High litter moisture content suppresses litter ammonia volatilization.

With global food demand expected to increase by 100% in the next 50 yr, urgency to combine comprehensive strategies for sustainable, efficacious, and environmentally sensible agronomic practices has never been greater. One effort for US meat bird management is to reduce NH(3) volatilization from litter to create a better growing environment for the birds, improve production efficiency, retain N in litter for fertilizer value, and negate the detrimental environmental impacts of NH(3) loss to the air. To derive the fundamental effects of temperature and moisture on litter NH(3) volatilization over the range of conditions found in commercial houses, experiments were conducted using commercial broiler litter that had moisture contents of approximately 20 to 55% while controlling temperatures ranging from 18.3 to 40.6°C. Litter samples (100 g) were placed in 1-L containers that received humidified air at approximately 113 mL/min. Volatilized NH(3) in exhaust air was captured in H(3)BO(3) traps. Ammonia loss (log(10) transformation) was modeled via an equation using linear coefficients for temperature and moisture, an interaction term for temperature × moisture, and a quadratic term for moisture. The surface responses resembled parabolic cylinders, indicating a critical moisture level at which NH(3) no longer increases but is diminished as moisture continues to increase. The critical moisture level lies between 37.4 and 51.1% litter moisture, depending on the temperature. An increase in temperature consistently increased NH(3) generation. When the temperature extremes were compared, the maximum NH(3) was up to 7 times greater at 40.6 vs. 18.3°C. The upper moisture limit at which NH(3) release is maximized and subsequently arrested as moisture continues to increase had not been defined previously for commercial broiler litter. The poultry industry and researchers can use these results as a decision tool to enable management strategies that limit NH(3) production.

Litter ammonia generation: moisture content and organic versus inorganic bedding materials.

Negative impacts on the environment, bird well-being, and farm worker health indicate the need for abatement strategies for poultry litter NH(3) generation. Type of bedding affects many parameters related to poultry production including NH(3) losses. In a randomized complete block design, 3 trials compared the cumulative NH(3) volatilization for laboratory-prepared litter (4 bedding types mixed with excreta) and commercial litter (sampled from a broiler house during the second flock on reused pine wood chips). Litters were assessed at the original moisture content and 2 higher moisture contents. Broiler excrement was mixed with pine wood shavings, rice hulls, sand, and vermiculite to create litter samples. Volumetrically uniform litter samples were placed in chambers receiving humidified air where the exhaust passed through H(3)BO(3) solution, trapping litter-emitted NH(3). At the original moisture content, sand and vermiculite litters generated the most NH(3) (5.3 and 9.1 mg of N, respectively) whereas wood shavings, commercial, and rice hull litters emitted the least NH(3) (0.9-2.6 mg of N). For reducing NH(3) emissions, the results support recommendations for using wood shavings and rice hulls, already popular bedding choices in the United States and worldwide. In this research, the organic bedding materials generated the least NH(3) at the original moisture content when compared with the inorganic materials. For each bedding type, incremental increases in litter moisture content increased NH(3) volatilization. However, the effects of bedding material on NH(3) volatilization at the increased moisture levels were not clearly differentiated across the treatments. Vermiculite generated the most NH(3) (26.3 mg of N) at the highest moisture content. Vermiculite was a novel bedding choice that has a high water absorption capacity, but because of high NH(3) generation, it is not recommended for further study as broiler bedding material. Controlling unnecessary moisture inputs to broiler litter is a key to controlling NH(3) emissions.

Spatial contrasts of seasonal and intraflock broiler litter trace gas emissions, physical and chemical properties.

Comprehensive mitigation strategies for gaseous emissions from broiler operations requires knowledge of the litters' physical and chemical properties, gas evolution, bird effects, as well as broiler house management and structure. This research estimated broiler litter surface fluxes for ammonia (NH3), nitrous oxide (N2O), and carbon dioxide (CO2). Ancillary measurements of litter temperature, litter total N, ammonium (NH4+), total C content, moisture, and pH were also made. Grid sampling was imposed over the floor area of two commercial broiler houses at the beginning (Day 1), middle (Day 23), and end (Day 43) of a winter and subsequent summer flock housed on reused pine shavings litter. The grid was composed of 36 points, three locations across the width, and 12 locations down the length of the houses. To observe feeder and waterer (F/W) influences on the parameters, eight additional sample locations were added in a crisscross pattern among these automated supply lines. Color variograms illustrate the nature of parameter changes within each flock and between seasons. Overall trends for the NH3, N2O, and CO2 gas fluxes indicate an increase in magnitude with bird age during a flock for both summer and winter, but flux estimates were reduced in areas where compacted litter (i.e., caked litter or cake) formed at the end of the flocks (at F/W locations and in the fan area). End of flock gas fluxes were estimated at 1040 mg NH3 m(-2) h(-1), 20 mg N2O m(-2) h(-1), and 24,200 mg CO2 m(-2) h(-1) in winter; and 843 mg NH3 m(-2) h(-1), 18 mg N2O m(-2) h(-1)), and 27,200 mg CO2 m(-2) h(-1) in summer. The results of intensive sample efforts during winter and summer flocks, reported visually using contour plots, offer a resource to the poultry industry and researchers for creating new management strategies for improving production and controlling gas evolution. Particularly, efforts could focus on designing housing systems that minimize extremes in litter compaction. The extremes are undesirable with more friable litter prone to greater gas evolution and more compacted litter providing a slippery, disease-sustaining surface.

Microbial and antibiotic resistant constituents associated with biological aerosols and poultry litter within a commercial poultry house.

Poultry are known to harbor antibiotic resistant and pathogenic bacteria, and as such poultry litter and poultry house air can be contaminated with these bacteria. However, the presence of antibiotic resistant bacteria in biological aerosols and litter is largely not understood. The purpose of this study was to determine the amount of aerosolized bacteria and endotoxin, particularly fecal indicators, staphylococci, and enterococci, associated with poultry house and outdoor air. Aerosol samples were collected at multiple locations on the farm and in the house. Antibiotic resistance was investigated using the Kirby Bauer method on selected isolates using twelve different antibiotics spanning both narrow to broad spectrums of effectiveness. Overall there was a cyclical increase in bacterial concentrations as flocks progressed from pre-flock to late-flock, with >2 orders magnitude lower concentration during pre-flock periods (no chickens), in both the litter and aerosol samples. The house environment provided for significantly concentrated bacterial and endotoxin levels. It was estimated that Staphylococcus bacteria accounted for at least 90% of cultured aerobic bacteria and culture-independent 16S rRNA analyses demonstrated that significant population changes occurred from pre- to late-flock. Rarely was an isolate resistant to more than 4 antibiotic classes; however there was a trend upwards in overall resistance of enterococci as the flock cycle progressed. It appears that although levels of antibiotic resistant bacteria were highly concentrated within the house, levels were much lower outside of the house, and very little house escape occurred.

Spatial shifts in microbial population structure within poultry litter associated with physicochemical properties.

Microbial populations within poultry litter have been largely ignored with the exception of potential human or livestock pathogens. A better understanding of the community structure and identity of the microbial populations within poultry litter could aid in the development of management practices that would reduce populations responsible for toxic air emissions and pathogen incidence. In this study, poultry litter air and physical properties were correlated to shifts in microbial community structure as analyzed by principal component analysis (PCA) and measured by denaturing gradient gel electrophoresis (DGGE). Litter samples were taken in a 36-point grid pattern at 5 m across and 12 m down a 146 m x 12.8 m chicken house. At each sample point, physical parameters such as litter moisture, pH, air and litter temperature, and relative humidity were recorded, and samples were taken for molecular analysis. The DGGE analysis showed that the banding pattern of samples from the back and water/feeder areas of poultry house were distinct from those of samples from other areas. There were distinct clusters of banding patterns corresponding to the front, middle front, middle back, back, and waterer/feeder areas. The PCA analysis showed similar cluster patterns, but with more distinct separation of the front and midhouse samples. The PCA analysis also showed that moisture content and litter temperature (accounting for 51.5 and 31.5% of the separation of samples, respectively) play a major role in spatial diversity of microbial community in the poultry house. Based on analysis of DGGE fingerprints and cloned DGGE band sequences, there appear to be differences in the types of microorganisms over the length of the house, which correspond to differences in the physical properties of the litter.

Valine requirements for immune and growth responses in broilers from 3 to 6 weeks of age.

Four experiments were conducted to evaluate valine (Val) requirements in Ross 508 broilers from 3 to 6 weeks of age. Common diets were fed to broilers until 3 weeks of age. Growth and carcass measurements were taken in all experiments. Immune responsiveness measurements were taken in Experiments 1 and 2. Birds given 7.2 g Val/kg of diet in Experiment 1 had more abdominal fat than birds given 8.2 g Val/kg of diet, but there were no differences in growth or other carcass measurements. Because growth performance was not reduced in birds given 7.2 g Val/kg of diet, Val concentration was reduced to 6.4 g Val/kg of diet in Experiments 2 and 3. Increasing Val from 6.4 to 8.7 g Val/kg of diet resulted in linear increases for BW gain, feed efficiency and Val intake in male birds, and Val intake in female birds. Quadratic responses to increasing dietary Val were not observed in any experiment. There were no effects of Val on innate or adaptive immunity. A nonessential amino acid mixture containing the same nitrogen content as the L-Val additions in Experiment 4 was added and tends to support the idea that the responses to Val were specific and not due to increases in total nitrogen. Dose responses to Val resulted in male, but not female, birds given 7.3 g Val/kg of diet having improved BW gain and feed efficiency compared with birds receiving 6.4 g Val/kg of diet.

Ocular responses to ammonia in broiler chickens.

In two trials, 60 male commercial broilers were placed in each of eight environmentally controlled chambers receiving 0, 25, 50, or 75 ppm aerial ammonia from 1 to 28 days. Birds exposed to 25 ppm (lower concentration) ammonia gas developed ocular abnormalities but at a slower rate when compared with birds exposed to 50 and 75 ppm (higher concentrations). Birds exposed to higher concentrations also developed more severe lesions. With little atmospheric ammonia present after 28 days of the grow-out stage, the corneas indicated signs of healing. Lymphocytes and heterophils were seen in the iris at 49 days in ammonia-exposed birds even when ammonia exposure was terminated at 28 days. The lower ammonia concentrations resulted in abnormalities that were slight when compared with those seen at the higher ammonia concentrations. As measured by the incidence of inflammatory infiltrates in the trachea, lung, and air sacs, respiratory tract tissues did not appear to be affected by any tested level of aerial ammonia. The findings in this investigation represent the first report indicating that ammonia-induced uveitis in chickens clears rapidly after exposure to ammonia ceases.

Spatial variability of litter gaseous flux within a commercial broiler house: ammonia, nitrous oxide, carbon dioxide, and methane.

Twenty-eight flocks were grown on litter in a tunnel-ventilated, curtain-sided commercial broiler house prior to this summer flock. Grid measurements were made using a photo-acoustic multigas analyzer to assess the spatial variability of litter gases (NH3, N2O, CO2, and CH4) on d 1 and 21. The pooled results for the brood and non-brood areas of the house were 1) NH3 flux was greatest in the brood area at d 1, averaging 497 mg/(m2 x h), and had a mean of 370 mg/(m2 x h) in the vacant end of the house; 2) at d 21, the non-brood area had the greater average NH3 flux, 310 mg/(m2 x h), and flux in the brood area was 136 mg/(m2 x h); 3) N2O and CH4 fluxes were <60 mg/(m2 x h); and 4) on d 1, brood CO2 flux was 6,190 mg/(m2 x h) compared with 5,490 mg/ (m2 x h) at the opposite end of the house. On d 21, these values increased to 6,540 and 9,684 mg/(m2 x h) for the brood and non-brood areas. Ammonia flux seemed most affected by litter temperature. Carbon dioxide and CH4 increased from placement to mid growout, corresponding to increased moisture, especially near the fans. Contour plots were developed using geostatistical software to visually assess the spatial disparity among the measurements. This research provides a unique view of gas flux variation within the house. Collinear factors such as house management, bird size and age, and amount of deposition are significant factors for litter gas flux and should be considered in comprehensive models for emission estimates.

Stocking density effects on growth performance and processing yields of heavy broilers.

This study examined responses of male broilers during a 49-d production cycle to 4 placement densities in 2 trials. Trials were pooled because no treatment x trial interaction occurred. In each trial, 1,488 male chicks were randomly placed into 32 floor pens to simulate final densities of 30 (37 chicks/pen), 35 (43 chicks/ pen), 40 (50 chicks/pen), and 45 (56 chicks/pen) kg of BW/m2 of floor space based on a projected final BW of 3.29 kg. Growth rate and nutrient utilization were similar (P > or = 0.05) among the treatments from 1 to 32 d of age. From 1 to 49 d, BW gain (P = 0.011) and feed consumption (P = 0.029) were adversely affected by increasing the placement density from 30 to 45 kg of BW/m2 of floor space. The reduction in cumulative BW gain due to placement density can be partially explained by less feed consumption as evidenced by 95.4% of the sums of squares of BW gain being attributable to feed consumption. Litter moisture content (P = 0.025) and foot pad lesion score (P = 0.001) increased linearly with increasing placement density. Upon processing, whole carcass and breast meat yields relative to BW were not affected (P > or = 0.05) as density increased from 30 to 45 kg/m2. The proportion of whole carcasses with scratches, but not tears, on the back and thighs increased (P = 0.021) as density increased. These results indicate that increasing the density beyond 30 kg/m2 elicited some negative effects on live performance of heavy broilers.

Decreasing phosphorus runoff losses from land-applied poultry litter with dietary modifications and alum addition.

Phosphorus (P) losses from pastures fertilized with poultry litter contribute to the degradation of surface water quality in the United States. Dietary modification and manure amendments may reduce potential P runoff losses from pastures. In the current study, broilers were fed a normal diet, phytase diet, high available phosphorus (HAP) corn diet, or HAP corn + phytase diet. Litter treatments were untreated control and alum added at 10% by weight between flocks. Phytase and HAP corn diets reduced litter dissolved P content in poultry litter by 10 and 35%, respectively, compared with the normal diet (789 mg P kg(-1)). Alum treatment of poultry litter reduced the amount of dissolved P by 47%, while a 74% reduction was noted after alum treatment of litter from the HAP corn + phytase diet. The P concentrations in runoff water were highest from plots receiving poultry litter from the normal diet, whereas plots receiving poultry litter from phytase and HAP corn diets had reduced P concentrations. The addition of alum to the various poultry litters reduced P runoff by 52 to 69%; the greatest reduction occurred when alum was used in conjunction with HAP corn and phytase. This study demonstrates the potential added benefits of using dietary modification in conjunction with manure amendments in poultry operations. Integrators and producers should consider the use of phytase, HAP corn, and alum to reduce potential P losses associated with poultry litter application to pastures.

Atmospheric ammonia is detrimental to the performance of modern commercial broilers.

Atmospheric ammonia inhibits broiler performance. Quantified effects are based on older genetic stock with a BW of 2000 g at 7 wk. In contrast, modern genetic stock reaches 3200 g at 7 wk of age. To assess the impact on present day broilers, 2 trials were conducted exposing male broilers to graded levels (0, 25, 50, and 75 ppm) of aerial ammonia from 0 to 4 wk of age. Sixty, 1-d-old chicks were placed in environmentally controlled chambers, weighed weekly as a group, and processed with yield determined at 7 wk of age. Final BW was significantly depressed by 6 and 9% for the 50 and 75 ppm concentrations of ammonia as compared with 0 ppm. Also, mortality was significantly greater at the 75 ppm ammonia concentration, 13.9% compared with 5.8% for the 0 ppm treatment. Percentage yield of deboned meat per bird decreased slightly with increasing exposure to ammonia but was not statistically significant. Although current genetic stock reaches growout weights that are approximately 60% greater than those 2 decades ago, the relative quantified effects of ammonia exposure were similar. Additionally, statistical analysis of the results provided a simple equation, presented herein, for predicting the decline in BW of male broilers after exposure to ammonia.

Total and water-soluble phosphorus in broiler litter over three flocks with alum litter treatment and dietary inclusion of high available phosphorus corn and phytase supplementation.

Three pen trials were conducted to determine the main effect of alum addition to litter on form of poultry litter P using a 2 x 2 factorial structure of the subunit treatments: diets including high available phosphorus/low phytate corn (HAPC) and phytase (PHYT). Male broilers (1,760 per flock) were grown to 42 d having starter diets with 0.45% available P and grower diets with 0.35% available P. In the first trial, total litter P (tP) was greatest for the yellow dent corn (YDC) diet (12 g/kg) and least for the HAPC and PHYT combination (H&P) diet (6.9 g/kg) with the individual PHYT and HAPC diets falling in between at 9.1 g/kg and 9.4 g/kg tP. Also in the first trial, the litter water-soluble P (wP) was highest for PHYT (2.8 g/kg), least for the HAPC and H&P diets (1.5 g/kg) with the YDC diet falling between (2.2 g/kg). Alum was added to the litter after the first experiment. In the second and third experiments, alum inclusion significantly reduced the wP when compared with the treatments with no alum. In the third trial, the least wP was present in the alum-HAPC treatment. Phytase, YDC, and HAPC diets with no alum litter treatment generated the most wP. Since these diets appear to have little or no difference with respect to quantity of wP, this work suggests that form of litter P generated by alternative diets should be considered as criteria when attempting to reduce P in broiler litter applied to land.

Mycoplasma gallinarum infection in commercial layers and onset of fatty liver hemorrhagic syndrome.

Fatty liver hemorrhagic syndrome (FLHS) was observed in each of three trials in which commercial layers were utilized to determine the effect of Mycoplasma gallinarum (MGn) on egg and eggshell quality parameters and egg production. In each of three trials, FLHS occurred 31-54 days later in MGn-inoculated hens as compared with the Mycoplasma-clean (control) hens. In trials 1 and 2, no therapeutic intervention was initiated to ameliorate FLHS. In trial 3, therapeutic intervention was instituted and consisted of the addition of 1 pound of choline chloride/ton of feed. Total mortality recorded throughout the duration of each trial and attributable to FLHS was not significantly different between the control and the MGn-inoculated treatment. However, FLHS-associated mortality in each of the three trials was numerically greater for the control treatment.

The effects of high-air velocity on broiler performance.

Two trials using a total of 1,484 Ross male broilers were conducted to study the effect of air velocities of 180 and 120 m/min versus still air (<15 m/min) on BW gain (BWG) and feed:gain from 3 to 7 wk of age. Broilers were raised in a common environment to 3 wk of age. The experimental facility was a closed sided house containing eight wind tunnel floor pens and six floor pens. There were two wind tunnels (four pens/tunnel) used to test air velocities of 180 or 120 m/min. At 3 wk of age, 53 birds were placed in pens on litter in each of two wind tunnels (four pens/tunnel) or on litter in floor pens (six pens) in an environmentally controlled facility. All floor pens contained 3.75 square meters of floor space, one tube feeder, and one trough waterer. The temperature regimen was a diurnal cycle of 25-30-25 C with 23 C dewpoint. Air velocities of 180 and 120 m/min had no significant effect on BWG or feed:gain during the first week (3 to 4 wk) in the tunnels as compared with the still air. However, significant improvements were noted in BWG and feed:gains for increased air velocities from 4 to 5 and 5 to 6 wk of age. During the last week (6 to 7), an air velocity of 180 m/min significantly improved BWG and feed:gain, as compared with the 120 m/min or the still air.

Hyaluronic acid increases motility/intracellular CA2+ concentration in human sperm in vitro.

This study investigated the mechanisms of the stimulatory effect of hyaluronic acid on motility in human sperm in vitro. A method, involving the measurement of forward progression through an agarose gel. was used to measure sperm motility quantitatively. Changes in intracellular Ca2+ concentrations in sperm were detected using the fluorescent dye Fluo-3. The effects of hyaluronic acid (6.5, 65, 650 ng/mL) and nifedipine (32 nM) on sperm motility were investigated. The effects of hyaluronic acid, nifedipine (32 nM), A23187 (32 microM), and a monoclonal antibody to human CD44 (1 microg/mL) on changes in intracellular CA2+ concentrations were investigated. Hyaluronic acid significantly (p < .008) stimulated sperm motility and this was partially inhibited by nifedipine. A23187 significantly (p < .005) increased intracellular CA2+ concentrations. Hyaluronic acid significantly (p < .04) increased intracellular Ca2+ concentrations and this was inhibited by nifedipine and a monoclonal antibody to human CD44. Hyaluronic acid stimulated human sperm motility by increasing intracellular Ca2+ concentration, partially via an influx of extracellular Ca2+.