Exploring effects of light intensity on sustainability indicators in finishing pig production.

With an ongoing transition towards the use of Light Emitting Diodes, more knowledge is needed on which light settings optimise sustainability parameters in pig production. We studied the effects of four light intensities on social, environmental and economic sustainability indicators, including ammonia emissions, space use, pen fouling, weight gain, carcass quality, perception of the stockkeeper, costs of the light system, and use of drinking water, electricity and medicines. Light treatments included a low (45 lux), medium (198 lux) and high (968 lux) uniform intensity, and a spatial gradient treatment ranging from 71 lux in the front to 330 lux in the back of each pen. The latter treatment aimed to improve the space use of functional areas. A total of 448 growing-finishing pigs were studied on a commercial farm using two consecutive batches of four rooms containing eight pens with seven pigs. Light intensity influenced some aspects of space use and pen fouling. For example, the proportion of pigs lying in the resting area was higher in the high and medium light intensity treatment than in the low intensity and gradient treatment. Moreover, the high-intensity treatment resulted in more fouling with faeces in the feeding area compared with the low-intensity and the gradient treatment. Ammonia emissions were higher in the gradient than in the low intensity treatment (not measured in medium and high intensity treatment). Furthermore, light intensity did not affect weight gain, carcass quality, water use and medicine use. The stockkeeper was content to work in all light conditions, but slightly preferred the medium intensity due to optimal visibility. Concerning economic performance, the costs of the light system and electricity use increased in the following order: low intensity, gradient, medium intensity, and high intensity. In conclusion, contrary to expectation the spatial gradient did not notably improve space use or reduce pen fouling, but rather increased ammonia emissions in comparison with uniform light. This is likely because the gradient could not be applied in an optimal way in the existing housing conditions. Among the other sustainability indicators, mainly electricity use and costs of the light system differed per treatment. These aspects can be improved by further optimising the number of light sources needed per pen to achieve the targeted intensities.

Evaporative water loss from dairy cows in climate-controlled respiration chambers.

The effects of ambient temperature (AT) on total evaporative water loss from dairy cows at different relative humidity (RH) and air velocity (AV) levels were studied. Twenty Holstein dairy cows with an average parity of 2.0 ± 0.7 and body weight of 687 ± 46 kg participated in the study. Two climate-controlled respiration chambers were used. The experimental indoor climate was programmed to follow a diurnal pattern with AT at night being 9°C lower than during the day. Night AT was gradually increased from 7 to 21°C and day AT was increased from 16°C to 30°C within an 8-d period, both with an incremental change of 2°C/d. The effect of 3 RH levels with a diurnal pattern were studied as well, with low values during the day and high values during the night: low (day, 30%; night, 50%), medium (day, 45%; night, 70%), and high (day, 60%; night, 90%). The effects of AV were studied during the daytime at 3 levels: no fan (0.1 m/s), fan at medium speed (1.0 m/s), and fan at high speed (1.5 m/s). The medium and high AV levels were only combined with medium RH. In total, there were 5 treatments with 4 replicates each. The animals had free access to feed and water. Based on the water balance principle inside the respiration chambers, the total evaporative water loss from dairy cows at a daily level was quantified by measuring the mass of water in the incoming and outgoing air, condensed water, added water from a humidifier, and evaporative water from a wet floor, drinking bowl, manure reservoir, and water bucket. Water evaporation from a sample skin area was measured with a ventilated skin box, and water evaporation, through respiration with a face mask. The results show that RH/AV levels had no significant effect on total evaporative water loss, whereas the interaction effect between RH/AV with AT was significant. Cows at a high RH had a tendency for a lower increasing rate of evaporative water loss compared with cows at a low RH (0.61 vs. 0.79 kg/d per 1°C increase of AT). Cows at medium and high AV levels had a greater increasing rate than cows at low AV (0.91 and 0.95 vs. 0.71 kg/d per 1°C increase of AT, respectively). The increase of evaporative heat loss from dairy cows was mainly a result of the increase in evaporation (of sweat) from the skin. The skin water evaporation determined with the water balance method (less evaporation from respiration) and the ventilated skin box method showed no significant difference. The implication of this study is that cows at a high AT depend mainly on evaporative cooling from the skin. The ventilated skin box method, measuring only a small part of the skin during a short period during the day, can be a convenient and accurate way to determine the total cutaneous evaporative water loss from cows.

Effects of increasing air temperature on skin and respiration heat loss from dairy cows at different relative humidity and air velocity levels.

The focus of this study was to identify the effects of increasing ambient temperature (T) at different relative humidity (RH) and air velocity (AV) levels on heat loss from the skin surface and through respiration of dairy cows. Twenty Holstein dairy cows with an average parity of 2.0 ± 0.7 and body weight of 687 ± 46 kg participated in the study. Two climate-controlled respiration chambers were used. The experimental indoor climate was programmed to follow a diurnal pattern with ambient T at night being 9°C lower than during the day. Night ambient T was gradually increased from 7 to 21°C and day ambient T was increased from 16 to 30°C within an 8-d period, both with an incremental change of 2°C per day. A diurnal pattern for RH was created as well, with low values during the day and high values during the night (low: RH_l = 30-50%; medium: RH_m = 45-70%; and high: RH_h = 60-90%). The effects of AV were studied during daytime at 3 levels (no fan: AV_l = 0.1 m/s; fan at medium speed: AV_m = 1.0 m/s; and fan at high speed: AV_h = 1.5 m/s). The AV_m and AV_h were combined only with RH_m. In total, there were 5 treatments with 4 replicates (cows) for each. Effects of short and long exposure time to warm condition were evaluated by collecting data 2 times a day, in the morning (short: 1-h exposure time) and afternoon (long: 8-h exposure time). The cows were allowed to adapt to the experimental conditions during 3 d before the main 8-d experimental period. The cows had free access to feed and water. Sensible heat loss (SHL) and latent heat loss (LHL) from the skin surface were measured using a ventilated skin box placed on the belly of the cow. These heat losses from respiration were measured with a face mask covering the cow's nose and mouth. The results showed that skin SHL decreased with increasing ambient T and the decreasing rate was not affected by RH or AV. The average skin SHL, however, was higher under medium and high AV levels, whereas it was similar under different RH levels. The skin LHL increased with increasing ambient T. There was no effect of RH on the increasing rate of LHL with ambient T. A larger increasing rate of skin LHL with ambient T was observed at high AV level compared with the other levels. Both RH and AV had no significant effects on respiration SHL or LHL. The cows lost more skin sensible heat and total respiration heat under long exposure than short exposure. When ambient T was below 20°C the total LHL (skin + respiration) represented approx. 50% of total heat loss, whereas above 28°C the LHL accounted for more than 70% of the total heat loss. Respiration heat loss increased by 34 and 24% under short and long exposures when ambient T rose from 16 to 32°C.

Effects of increasing air temperature on physiological and productive responses of dairy cows at different relative humidity and air velocity levels.

This study determined the effects of increasing ambient temperature (T) at different relative humidity (RH) and air velocity (AV) levels on the physiological and productive responses of dairy cows. Twenty Holstein dairy cows were housed inside climate-controlled respiration chambers, in which the climate was programmed to follow a daily pattern of lower night and higher day T with a 9°C difference, excluding effects from sun radiation. Within our 8-d data collection period, T was gradually increased from 7 to 21°C during the night (12 h) and 16 to 30°C during the day (12 h), with an incremental change of 2°C per day for both nighttime and daytime T. During each research period, RH and AV were kept constant at 1 of 5 treatment levels. A diurnal pattern for RH was created, with lower levels during the day and higher levels during the night: low (RH_l: 30-50%), medium (RH_m: 45-70%), and high (RH_h: 60-90%). The effects of AV were studied during the day at 3 levels: no fan (AV_l: 0.1 m/s), fan at medium speed (AV_m: 1.0 m/s), and fan at high speed (AV_h: 1.5 m/s). Effects of short and long exposure time to increasing T were evaluated by collecting data 2 times a day: in the morning [short: 1 h (or less) - exposure time] and afternoon (long: 8 h - exposure time). The animals had free access to feed and water and both were ad libitum. Respiration rate (RR), rectal temperature (RT), skin temperature (ST), dry matter intake, water intake, milk yield, and composition were measured. The inflection point temperatures (IPt) at which a certain variable started to change were determined for the different RH and AV levels and different exposure times. Results showed that IPt under long exposure time for RR (first indicator) varied between 18.9 and 25.5°C but was between 20.1 and 25.9°C for RT (a delayed indicator). The IPt for both RR and RT decreased with higher RH levels, whereas IPt increased with higher AV for RR but gave a minor change for RT. The ST was positively correlated with ambient T and ST was not affected by RH but significantly affected by AV. For RR, all IPt was lower under long exposure time than under short exposure time. The combination of higher RH levels and low AV level negatively affected dry matter intake. Water intake increased under all treatments except RH_l-AV_l. Treatment RH_h-AV_l negatively affected milk protein and fat yield, whereas treatments RH_m-AV_m and RH_m-AV_h reduced milk fat yield. We concluded that RH and AV significantly affected the responses of RR, RT, ST, and productive performance of high-producing Holstein cows. These responses already occurred at moderate ambient T of 19 to 26°C.

Effects of dietary crude protein levels on ammonia emission, litter and manure composition, N losses, and water intake in broiler breeders.

This study determined the effects of different dietary crude protein (CP) levels on ammonia emission (NH3), litter and manure composition, nitrogen (N) losses, and water intake in broiler breeders. A total of 480 females and 64 males (Ross 308) 20 wk of age were randomly allotted to 2 dietary treatments with 8 replicates of 30 females and 4 males per replicate. Birds were fed either high CP (CPh) or low CP diets (CPl) supplemented with free amino acids (AA). Both diets consisted of 3 sub-diets; 1 for each phase of the laying period. Diets were formulated to be iso-caloric and calculated CP content of the CPl diets was 15 g/kg lower than the CPh diets (Breeder 1 (23 to 34 wk): 135 vs. 150, Breeder 2 (35 to 46 wk): 125 vs. 140 and Breeder 3 (47 to 60 wk of age): 115 vs. 130 g/kg, respectively). Pens consisted of an elevated slatted floor (25% of the floor surface) and a litter floor. Water and feed intake were recorded daily. Litter (floor) and manure (below slatted floor) composition and ammonia concentration were measured at 34, 44, and 54 wk of age. Ammonia concentration was measured using a flux chamber on top of the litter or manure. Estimated N losses were calculated. Dietary protein level did not affect water intake and dry matter (DM) content of the litter or manure. Compared to birds fed the CPh diets, the litter and manure samples of broiler breeders fed the CPl had 8% lower total-N and 13% lower ammonia-N content resulting in a 9% lower ammonia concentration, 9% lower ammonia emission, and 11% lower total-N losses. In conclusion, this study shows that reducing CP level in the diet of broiler breeders reduces ammonia emission and total N-losses from litter and manure.

Impact of reduced exposure to calcineurin inhibitors on the development of de novo DSA: a cohort of non-immunized first kidney graft recipients between 2007 and 2014.

BACKGROUND: In low-immunological risk kidney transplant recipients (KTRs), reduced exposure to calcineurin inhibitor (CNI) appears particularly attractive for avoiding adverse events, but may increase the risk of developing de novo Donor Specific Antibodies (dnDSA). METHODS: CNI exposure was retrospectively analyzed in 247 non-HLA immunized first KTRs by taking into account trough levels (C0) collected during follow-up. Reduced exposure to CNI was defined as follows: C0 less than the lower limit of the international targets for ≥50% of follow-up. RESULTS: During a mean follow-up of 5.0 ± 2.0 years, 39 patients (15.8%) developed dnDSA (MFI ≥1000). Patients with DSA were significantly younger (46.6 ± 13.8 vs. 51.7 ± 14.0 years, p = 0.039), received more frequently poorly-matched grafts (59% with 6-8 A-B-DR-DQ HLA mismatches vs. 34.6%, p = 0.016) and had more frequently a reduced exposure to CNI (92.3% vs. 62.0%, p = 0.0002). Reduced exposure to CNI was associated with an increased risk of dnDSA (multivariable HR = 9.77, p = 0.002). Reduced exposure to CNI had no effect on patient survival, graft loss from any cause including death, or post-transplant cancer. CONCLUSIONS: Even in a low-immunological risk population, reduced exposure to CNI is associated with increased risk of dnDSA. Benefits and risks of under-immunosuppression must be carefully evaluated before deciding on CNI minimization.

Temporal Trend and Time-Varying Effect of Preemptive Second Kidney Transplantation on Graft Survival: A 30-Year Single-Center Cohort Study.

BACKGROUND: There are discrepancies regarding the impact of preemptive 2nd kidney transplantation (PSKT) on graft survival. The present study aimed to determine whether the association between PSKT and outcome varies over time and whether this association is era dependent. METHODS: A total of 266 patients underwent SKT (244 non-PSKT, 22 PSKT) in our center from 1985 to 2015. Association between PSKT and graft survival (allograft failure from any cause including death) was assessed with the use of Cox models. RESULTS: During a median follow-up of 6.7 years, 116 events were recorded: 72 returns to dialysis and 44 deaths before return to dialysis. Survival curves diverged up to 5 years (5-year survivals: PSKT, 94.1 ± 5.7%; non-PSKT, 76.8 ± 2.9%) but they converged thereafter (12-year survivals: PSKT, 50.9 ± 15.2%; non-PSKT, 55.5 ± 3.9%). After adjustment for age and living-donor status, PSKT tended to be associated with better graft survival (hazard ratio [HR], 0.18; 95% confidence interval [CI], 0.02-1.27; P = .08) within the first 5 years of SKT but tended to be associated with worse outcome thereafter (HR, 2.36; 95% CI, 0.97-5.72; P = .06; P for interaction with time = .04). In addition, a significant interaction was identified between PSKT and SKT year (P for interaction = .04). In the multivariable model, the estimated HR for PSKT was 2.54 (95% CI, 0.88-7.35; P = .08) in 1990 as opposed to 0.16 (95% CI, 0.02-1.17; P = .07) in 2012. CONCLUSIONS: The effect of PSKT on graft survival varies over time and according to year of the procedure. Although the benefit observed within the first 5 years of SKT appears to fade over time, overall graft survival seemingly improved in more recent years.

Abatement of particulate matter emission from experimental aviary housings for laying hens by spraying rapeseed oil.

In alternative systems for laying hens, concentrations and emission rates of particulate matter (PM) give reason for concern with regard to working conditions, bird health and productivity, and health of residents living near farms. Previously, we found that spraying a film of rapeseed oil onto the litter of broilers could substantially reduce PM concentrations and emissions. The objective of this study was to establish dose-response effects of oil spraying in aviaries on concentrations and emission rates of PM with aerodynamic diameters less than 10 µm (PM10) and 2.5 µm (PM2.5), on stockmen's exposure to PM10, on egg production, exterior quality and behavior of the hens, and on the litter. An experiment was carried out with 4 treatments: 0 (control), 15, 30, and 45 mL/m2 per d (oil treatments). Each treatment was applied in 2 rooms with different aviary systems (8 rooms in total). The experiment was repeated during a second period, both lasting 35 days. From d 11 to d 35, oil was applied daily using a spraying gun. Applying 15, 30, or 45 mL/m2 per d significantly reduced emission rates of PM10 by 27, 62, and 82%, and emission rates of PM2.5 by 71, 83, and 94%, respectively. No significant effects of oil spraying were found on mortality, egg production, dust bathing behavior, scratching behavior, plumage soiling, DM content of the litter, or friability of the litter. A significant worsening of the plumage condition was found only for the body spot back/wings/tail (not for: throat/neck, chest/breast, or legs) in the 45 mL/m2 per d treatment. Egg quality shifted significantly towards more second-class eggs in the oil treatments (1.9% versus 1.4%; P = 0.004). Remarkably, foot soiling decreased with increasing oil application. In conclusion, PM concentrations and emission rates in aviaries can be effectively reduced by spraying 15 to 30 mL/m2 per d with minor side effects within a 25 d application period.

MHC polymorphism in Caribbean African green monkeys.

African green monkeys (AGM) are among the most widely used nonhuman primate models used in various fields of medical research. One species of AGM that originated from West Africa, Chlorocebus sabaeus, was introduced three centuries ago in the Caribbean islands. We present here a systematic study of the major histocompatibility complex (MHC) polymorphism of Caribbean AGM which is currently frequently used as an animal model. We studied 54 animals originated from Barbados (N=25) or Saint Kitts (N=29). The MHC polymorphism was characterized by means of 17 MHC microsatellites spread across MHC and DRB genotyping by DGGE sequencing. We defined nine frequent MHC haplotypes of which two were found in the two insular populations suggesting either past exchanges between the two populations or a common origin of the founders of the two populations. By the analysis of a previously described EST library, we characterized 38 MHC cDNA sequences (17 class I and 21 class II). In conclusion, we characterized for the first time the MHC polymorphism of Barbados and Saint Kitts AGM. We found a restricted polymorphism due to a founding effect, which is responsible for a strong bottleneck. The poorness of MHC polymorphism observed in the Caribbean AGM populations is similar to that observed in the Mauritian cynomolgus macaque population.

Study of MHC class II region polymorphism in the Filipino cynomolgus macaque population.

The cynomolgus macaque (Macaca fascicularis) is currently used as an animal model in various fields of immunology especially in the development of innovative vaccines for the prevention and treatment of infectious diseases. The polymorphism of the major histocompatibility complex (MHC) influences the development of adaptive immune responses and it is crucial to characterize the polymorphism of cynomolgus MHC genes. We present here a systematic study of the MHC class II haplotypes in the Filipino macaque population. By the study of a large sample of Filipino animals (N = 353), we have characterized 18 MHC class II haplotypes by means of genotyping seven microsatellites. The animals were DRB genotyped by means of PCR-SSO or DGGE-sequencing on genomic amplified fragments. We cloned and sequenced the complementary DNA (cDNA) of DQA, DQB, DPA, and DPB genes of 117 animals. Combining the microsatellite genotyping and cDNA characterized in the 117 animals, we defined genetic association between the cDNA and the microsatellites and characterized 18 MHC class II haplotypes. For 104 animals out of the 353 studied, the presence of a recombinant haplotype was highly probable. Thirty-four percent of recombination was located in 256 kb segment between D6S2876 and D6S2747 microsatellites, a region encompassing several hot spots of recombination in the human MHC.

Localization and (semi-)quantification of fluorescent beads of 2 sizes in chickens over time after simultaneous intratracheal and cloacal administration.

Environmental particles enter the chicken via several routes. Entry via the respiratory and cloacal routes likely activates immune responses. We studied the localization of simultaneous intratracheally and cloacally applied beads of 2 sizes in the chicken body in time, and when possible, semiquantified the amount of beads. Ten broiler hens, 3.5 wk of age, received 1.25 × 10(9) 1.0-µm beads and 1.05 × 10(7) 10-µm fluorescein isothiocyanate (green) labeled cloacally, and simultaneously the same number and same sizes of tetramethylrhodamine isothiocyanate (red) labeled beads intratracheally. The bursa of Fabricius, lung, liver, kidney, gallbladder, spleen, thymus, small intestine (upper ileum), cecum, intestinal luminal contents, aerated bones, feces, and blood, from 2 chickens per moment were sampled at 1 h, 6 h, 24 h, 48 h, and 1 wk after challenge and studied for the presence of beads using fluorescence microscopy. The highest amount of beads was found in organs closest to the application site after 1 h (i.e., the lungs for red beads, and the bursa for green beads). All tissue samples showed all 4 types of beads at all time moments, most of them within 1 h. Lower levels of beads were found in lungs and bursa after 6 h and in all other organs after 24 h, except for the kidneys where levels declined after 48 h. Surprisingly, beads were found in thymus tissue and only relatively few beads were found in the spleen. At 1 h, 1-µm intratracheally applied red beads were also found in the cecal luminal content and cecal tissue, but not in the small intestinal luminal content, suggesting that ceca are capable of excreting small particles entering the body via the respiratory route. The presence of nondegradable and nonimmunogenic beads of different sizes in all sampled organs throughout the whole chicken body for 7 d suggested potentially negative chronic health and welfare risks for the chicken of environmental particles.

Viral shedding and emission of airborne infectious bursal disease virus from a broiler room.

1. The significance of airborne transmission in epidemics of infectious diseases in the livestock production industry remains unclear. The study therefore investigated the shedding route (faeces vs. exhaled air) of a vaccine strain of infectious bursal disease virus (IBDV) by broilers and the emission of airborne virus. 2. The experimental room contained 526 broilers which were orally inoculated at the age of 20 d. The airborne virus was sampled by three different bioaerosol samplers: Andersen six-stage impactor, all-glass impinger (AGI-30) and OMNI-3000. 3. Infected broilers started to shed virus in faeces on d 5 post inoculation (PI), and stopped shedding on d 12 PI. The faecal virus remained detectable for at least two d after drying under broiler room conditions. No virus was detected in the air exhaled by broilers. 4. Airborne virus was collected on d 5, 8 and 12 PI at 20 cm above the floor, and on d 8 and 12 PI in exhausted air. The emission rates of IBDV were 4·0 log10 50% tissue culture infectious dose (TCID50)/bird/d on d 8 PI, and 4·5 log10 TCID50/bird/d on d 12 PI. 5. We concluded that broilers shed IBDV mainly through their faeces. The presence of indoor airborne virus is associated with the viral presence in faeces. The successful recovery of airborne virus in exhausted air indicates there is a potential risk of virus spreading to the ambient environment via air.

Positive selection in the major histocompatibility complex class III region of cynomolgus macaques (Macaca fascicularis) of the Philippines origin.

The cynomolgus macaque (Macaca fascicularis) is a model of choice among primates for the study of local adaptation processes because of its mixed and wide insular and continental distribution. In a previous study, by using 12 markers [5 microsatellites located in the major histocompatibility complex (MHC) region and 7 outside MHC], we have detected a signal of positive selection on the microsatellite DRACA located inside the gene DRA. In order to refine the location of this signal of positive selection in the MHC region, we studied the genetic diversity of 36 markers (18 microsatellites spread across the MHC region and 18 autosomal microsatellites outside MHC) in a sample of 254 individuals from four populations (Vietnam, Java, the Philippines, and Mauritius). We estimated for each locus the deviation of F(st) from a neutral model by using two methods based on contrasted demographic models. The two approaches showed a signal of positive selection in the MHC class III region that is much more significant than the one previously reported for the marker DRACA which could have been influenced by a hitchhiking effect due to its proximity with the class III region.

Effects of 2 size classes of intratracheally administered airborne dust particles on primary and secondary specific antibody responses and body weight gain of broilers: a pilot study on the effects of naturally occurring dust.

We studied the effects of a concurrent challenge on slow-growing broilers with 1) airborne particles of 2 sizes: fine dust (smaller than 2.5 microns) and coarse dust (between 2.5 and 10 microns) that were directly collected from a broiler house and 2) lipopolysaccharide on intratracheal immunizations with the specific antigen human serum albumin (HuSA) and measured primary and secondary systemic (total) antibody responses and (isotype-specific) IgM, IgG, and IgA responses at 3 and 7 wk of age. All treatments affected immune responses at several ages, heart morphology, and BW gain, albeit the latter only temporarily. Dust particles significantly decreased primary antibody (IgT and IgG) responses to HuSA at 3 wk of age but enhanced IgM responses to HuSA at 7 wk of age. Dust particles decreased secondary antibody responses to HuSA, albeit not significantly. All of the birds that were challenged with dust particles showed decreased BW gain after the primary but not after the secondary challenge. Relative heart weight was significantly decreased in birds challenged with coarse dust, fine dust, lipopolysaccharide, and HuSA at 3 wk of age, but not in birds challenged at 7 wk of age. Morphology (weight, width, and length) of hearts were also affected by the dust challenge at 3 wk of age. The present results indicate that airborne dust particles obtained from a broiler house when intratracheally administered at an early age affect specific humoral immune responsiveness and BW gain of broilers to simultaneously administered antigens differently than when administered at a later age. The hygienic status of broiler houses at a young age may be of importance for growth and immune responsiveness, and consequently, for vaccine efficacy and disease resistance in broilers. The consequences of our findings are discussed.

Total loss and distribution of nitrogen and phosphorus in the outdoor run of organic laying hens.

1. The objective of this study was to determine the level and variation of the total mass, and load of nitrogen (N) and phosphorus (P) excreted into the outdoor run of organic egg production systems. 2. Three egg production farms with an aviary system and an outdoor run were selected for this study. Four measurements, one per season, were executed on each farm. 3. Mean content of N and P of a manure dropping was 14·0 g N kg⁻¹ and 3·12 g P kg⁻¹, mean mass of a dropping was 6·36 g and mean dry matter content of a dropping was 238 g kg⁻¹. Mean rate of excretion in the outdoor run was 2·99 droppings per hen per h. Mean percentage of hens outside during the time the outdoor run could be accessed was lowest on Farm 1 (1·7%), highest on Farm 2 (16·0%), and intermediate on Farm 3 (7·1%). 4. On all farms an exponential decrease of the number of hens and of the load of N and P with increasing distance from the hen house was found. Load of N exceeded the fertilisation standard (of 170 kg ha⁻¹y⁻¹) in the region at a 0 to 19 m distance from the hen house on Farm 1, 0 to 146 m on Farm 2 and 0 to 52 m on Farm 3. 5. It is concluded that the husbandry system should be redesigned to solve the problem of overloading, unwanted loss of N and P to the environment and loss of N and P from the organic production cycle.

Ultra-thin atomic layer deposited TiN films: non-linear I-V behaviour and the importance of surface passivation.

We report the electrical resistivity of atomic layer deposited TiN thin films in the thickness range 2.5-20 nm. The measurements were carried out using the circular transfer length method structures. For the films with thickness in the range of 10-20 nm, the measurements exhibited linear current-voltage (I-V) curves. The sheet resistance R(sh) was determined, and the resistivity was calculated. A value of 120 microohms-cm was obtained for a 20 nm TiN layer. With decreasing film thickness, the resistivity slightly increased and reached 135 microohms-cm for a 10 nm film. However, the measurements on 2.5-5.0 nm thick films revealed non-linear I-V characteristics, implying the dependence of the measured resistance, and therefore the resistivity, of the layers on applied voltage. The influence of the native oxidation due to the exposure of the films to air was taken into account. To fully eliminate this oxidation, a highly-resistive amorphous silicon layer was deposited directly after the ALD of TiN. The electrical measurements on the passivated 2.5- and 3.5 nm TiN layers then exhibited linear I-V characteristics. A resistivity of 400 and 310 microohms-cm was obtained for a 2.5- and 3.5 nm TiN film, respectively.

Effects of repeated intratracheally administered lipopolysaccharide on primary and secondary specific antibody responses and on body weight gain of broilers.

Earlier, we reported that pathogen-associated molecular patterns such as lipopolysaccharide (LPS), when administered intratracheally (i.t.), affected primary and secondary specific antibody responses to antigens administered concurrently, either i.t. or systemically, and also affected BW gain (BWG) of layers and broilers. In the present study, we evaluated the effects of repeated i.t. challenge with LPS concurrently with or before i.t. immunizations with the specific antigens human serum albumin (HuSA) and rabbit gamma globulin (RGG) on primary (HuSA, RGG) and secondary (HuSA) systemic antibody responses and (isotype) IgM and IgG responses at 2 different ages. Broilers were challenged via the trachea at 3 and 7 wk of age with various combinations of LPS, HuSA, and RGG. All treatments affected immune responses at several time points and also affected BWG, albeit temporarily for the latter. Lipopolysaccharide enhanced primary antibody responses to HuSA and to RGG, when challenged concurrently, but birds challenged solely with LPS at 3 wk of age also showed enhanced primary antibody responses to HuSA and RGG given at 7 wk of age. This was true for IgM as well as IgG isotype responses. Lipopolysaccharide challenge negatively affected BWG at 3 wk of age, whereas the negative effects of LPS after a secondary LPS challenge at 7 wk of age were most pronounced in the birds challenged with LPS at 3 wk of age. The present results indicated that LPS, when administered i.t. at a young age, may affect specific humoral immune responsiveness to antigens administered simultaneously and to BWG of broilers, but also when challenged 4 wk later with specific antigens, suggesting an enhanced status of immune reactivity or sensitivity. The hygienic status of broiler houses at a young age may thus influence BWG, immune responsiveness, and, consequently, the vaccine efficacy and disease resistance in broilers at later ages. The consequences of our findings are discussed.