This study aimed to investigate dust and bacterial air contamination in a broiler house during different seasons. The study was carried out in commercial housing conditions during five weeks of the rearing cycle in summer and winter. The total dust concentration ranged from 1.90 to 4.50 mg/m³ in summer and from 2.80 to 5.10 mg/m³ in winter. The total bacterial count ranged from 2.85 × 10⁴ to 1.03 × 10⁵ CFU/m³ in summer and from 2.12 × 10⁴ to 2.28 × 10⁵ CFU/m³ in winter. The study results showed the dust concentration to be increased in winter as compared to summer, yielding a significant correlation (r = 0.602, p < 0.05) with a significantly higher airborne bacterial count in winter (p < 0.001). Furthermore, dust concentration showed significant correlations (p < 0.05) with air temperature (r = −0.418), relative humidity (r = 0.673), and broiler activity (r = 0.709), while bacterial count yielded significant correlations (p < 0.05) with air temperature (r = −0.756), relative humidity (r = 0.831), and airflow rate (r = 0.511). The results obtained in the study can prove useful in the field. Seasonal variability in dust and bacterial air contamination should be considered in the development of guidelines or standards of air quality in broiler housing and evaluation of the effectiveness of remedial strategies.

The noninvasive biomarkers of respiratory impairment were assessed in 15 swine confinement (SC) workers and 9 respiratory healthy, nonsmoking volunteers (HV). Spirometry, fraction of exhaled nitric oxide (FeNO), and exhaled breath condensate (EBC) pH were assessed in SC workers after one working shift and one working week and in HV after 5-hour exposure in SC. Half of the respiratory symptoms (in 8 of 15 SC workers) were work-related. Basal FeNO values were 7.5 ppb higher in the SC workers compared with HV. In the SC workers, EBC pH increased for 0.17 at the end of a working week (P < 0.001). In HV, 5-hour exposure in SC induced 8% drop in forced expiratory flow at 25% of the pulmonary volume (FEF25) (P = 0.008), EBC pH drop for 0.10 units (P = 0.003), and FeNO drop by 1.8 ppb (P = 0.047). EBC pH was suggested as a biomarker of acute airway acidification in HV, whereas the SC workers showed signs of the "healthy worker effect."

Kvaliteta stelje je među glavnim čimbenicima o kojima ovise dobrobit i proizvodnost tovnih pilića. Intenzivan rast i razvoj pilića u tovu rezultiraju produljenim razdobljima odmora, što u kombinaciji s lošom kvalitetom stelje pogoduje pojavi kontaktnog dermatitisa na jastučićima nogu, tarzalnim zglobovima i prsima. Kontaktni dermatitis negativno utječe na zdravlje i dobrobit pilića, kvalitetu i zdravstvenu ispravnost mesa te ekonomiku proizvodnje. Glavni uzroci kontaktnog dermatitisa su vlaga i kemijske supstance u stelji koje djeluju nadražujuće, uz mnoštvo čimbenika koji utječu na njegovu pojavnost. S obzirom na utjecaj visine stelje na pojavnost kontaktnog dermatitisa, dosadašnji radovi izvještavaju o različitim, čak oprečnim rezultatima, koji iziskuju daljnja istraživanja. Dodatan naglasak potrebno je staviti na istraživanja utjecaja visine stelje na proizvodnost te kvalitetu i zdravstvenu ispravnost pilećeg mesa.

The aim of the study was to assess the effect of environmental enrichment and different stocking densities on the level of stress in the fattening cattle by measuring salivary cortisol concentration. A total of 320 saliva samples obtained from heifers during the final four-month fattening period was analyzed by a colorimetric competitive enzyme immunoassay. The heifers were housed at 3.3 and 4.5 m2/animal in standard production conditions that were additionally enriched with a mechanical grooming brush and salt blocks in experimental groups. The study results have demonstrated that a cortisol concentration at the end of fattening was significantly higher, as compared with the initial levels in all heifer groups, without significant intergroup differences. There was no significant correlation between the usage of a grooming brush and cortisol concentration, whereas a significant negative correlation was detected between the salt block usage and cortisol concentration, suggesting a beneficial effect of this simple, commercially available and relatively inexpensive environmental enrichment.

Air quality in zoo premises is insufficiently investigated, yet scientific interest is growing. In these places, air pollutants such as microorganisms may represent health risk for both animals and exposed people. Thus, maintaining good air quality is crucial for ensuring long-term sustainability of zoo operations. The present study aimed to assess bacterial air contamination level and microclimate conditions in Zagreb Zoo. Measurements were performed in the area for visitors and employees inside four premises, i.e., Monkey House, Tropical House, Rainy Africa, and Bird House, as well as outside the premises in the summer–autumn period. Total number of bacteria in the premises ranged from 4.50 × 10² to 3.70 × 10⁴ CFU/m³, and number of Gram-negative bacteria ranged from 0 to 5.50 × 10² CFU/m³. Total number of bacteria in outdoor air ranged from 50 to 8.50 × 10² CFU/m³, and number of Gram-negative bacteria ranged from 0 to 50 CFU/m³. Total number of bacteria was significantly higher in the Rainy Africa and Bird House as compared to the Monkey House and Tropical House, yielding a significant positive correlation with the number of Gram-negative bacteria in the premises. Total number of bacteria in outdoor air was significantly lower as compared to all investigated premises, except for the Monkey House, yielding a significant positive correlation with the number of Gram-negative bacteria outdoors. Air temperature showed a significant negative correlation with both total number of bacteria and number of Gram-negative bacteria, and airflow rate showed a significant negative correlation with total number of bacteria in the premises. Air temperature showed a significant positive correlation and relative humidity significant negative correlation with total number of bacteria outdoors. Study results can serve in the development of air quality standards in zoos, contributing to finding effective strategies to mitigate health risk from bioaerosols, with implications for occupational and public health, and overall zoo sustainability.

Air quality management in zoological gardens plays a crucial role in their sustainable development. However, air quality in these settings remains understudied. In addition, previous research has largely focused on airborne microbial contamination merely in animal enclosures. This exploratory study provides preliminary insights into airborne fungal contamination alongside microclimate conditions in the visitor and worker areas of animal premises in the Zagreb Zoo. The study was performed in the Monkey House, Tropical House, Rainy Africa, and Bird House, as well as outdoors in fall. Fungi were identified based on macroscopic and microscopic examinations. Total culturable fungal concentration in indoor air ranged between 50 and 4.25 × 10³ CFU/m³, and in outdoor air between 1.00 × 10² and 1.50 × 10³ CFU/m³. Molds of eight genera and yeasts were isolated from the air. Both indoors and outdoors, the predominant genera were Cladosporium and Penicillium, and also genus Aspergillus indoors. Cladosporium spp. and Penicillium spp. concentrations, as well as total fungal concentration in the air, were on average, highest in Rainy Africa and Bird House, while the highest average Aspergillus spp. concentration was found in the Tropical House. Levels of Cladosporium spp., Penicillium spp., and Aspergillus spp. concentrations were associated with microclimate conditions. Study results suggest that the airborne fungal contamination may depend on the animals housed in the premises, and the design and management of the premises. Although total fungal concentration determined may not necessarily pose a health risk for exposed people, the qualitative composition of fungi signifies the importance of implementing good practices in zoo premises, including optimal microclimate conditions and effective ventilation. The results obtained also indicate the need for air quality monitoring, which concurs with zoo sustainability goals.