Abstract. An unsatisfactory microclimate in poultry premises contributes to damage in the form of a decrease in the average daily gain of broilers by 10 %. Purpose of research is to study the effect of relative humidity at the same temperature regime on the immunity and productivity of broilers of the Ross-308. Research methods. The experiment was carried out on broiler chickens of the cross Ross-308 up to 35 days of age. In group II, period 0–1 days of growing broilers, the relative humidity indicators were less than the lower limit of the norm by 10 %, in periods 5–7, 11–16, 20–22 and 26–35 days, the relative humidity indicators were less than the lower limit of the norm by 5 %. In group I, all indicators were recommended as recommended. The bactericidal activity of blood serum was determined by the method of I. M. Karput, lysozyme activity was determined by the nephelometric method according to V. G. Dorofeychuk. Results. As a result of the study, it was found that a decrease in the change in relative air humidity had a negative effect on immunity: the bactericidal and lysozyme activity of blood serum decreased. So, on the 21st day, the indicator of bactericidal activity of blood serum of broiler chickens in group II was lower by 14.2 % (P ≤ 0.05) compared to group I. At 3 weeks of age, the lysozyme activity of the blood serum of chickens of group II was lower by 14.3 % (P ≤ 0.05) compared to the control group. The productivity of birds also decreased to 13.70 % in relation to the control. Scientific novelty. For the first time, we have shown that a decrease in the indicators of relative air humidity at the content of Ross-308 cross broilers during the period of 0–1 days of cultivation by 10 % relative to the lower limit of the norm, during the periods of 5–7, 11–16, 20–22 and 26–35 days – by 5 %, subject to the recommended temperature parameters, has a negative effect on immunity.
broiler, microclimate, temperature and humidity regime, maintenance, immunity
1. Gicheha M. G. The Effects of Heat Stress on Production. Reproduction. Health in Chicken and Its Dietary Amelioration // Advances in Poultry Nutrition Research. 2021. DOI:https://doi.org/10.5772/intechopen.97284.
2. Gonzalez-Rivas P. A., Chauhan S. S., Ha M., Fegan N., Dunshea F. R., Warner R. D. Effects of heat stress on animal physiology, metabolism, and meat quality: A review // Meat science. 2020. No. 162. Article number 108025. DOI:https://doi.org/10.1016/j.meatsci.2019.108025.
3. Brugaletta G., Teyssier J. R., Rochell S. J., Dridi S., Sirri F. A review of heat stress in chickens. Part I: Insights into physiology and gut health // Frontiers in physiology. 2022. No. 13. Article number 934381. DOI:https://doi.org/10.3389/fphys.2022.934381.
4. Rostagno M. H. Effects of heat stress on the gut health of poultry // Journal of animal science. 2020. No. 98 (4). Article number skaa090. DOI:https://doi.org/10.1093/jas/skaa090.
5. Ricke S. C., Dawoud T. M., Kim S. A., Park S. H., Kwon Y. M. Salmonella Cold Stress Response: Mechanisms and Occurrence in Foods // Advances in applied microbiology. 2018. No. 104. Rr. 1-38. DOI:https://doi.org/10.1016/bs.aambs.2018.03.001.
6. Zhou H. J., Kong L. L., Zhu L. X., Hu X. Y., Busye J., Song Z. G. Effects of cold stress on growth performance, serum biochemistry, intestinal barrier molecules, and adenosine monophosphate-activated protein kinase in broilers // Animal. 2021. No. 15 (3). Article number 100138. DOI:https://doi.org/10.1016/j.animal.2020.100138.
7. Sztandarski P., Marchewka J., Wojciechowski F., Riber A. B., Gunnarsson S., Horbańczuk J. O. Associations between weather conditions and individual range use by commercial and heritage chickens // Poultry science. 2021. No. 100 (8). Article number 101265. DOI:https://doi.org/10.1016/j.psj.2021.101265.
8. Goel A. Heat stress management in poultry // Journal of animal physiology and animal nutrition. 2021. No. 105(6). Pp. 1136-1145. DOI:https://doi.org/10.1111/jpn.13496.
9. Kim D. H., Lee Y. K., Kim S. H., Lee K. W. The Impact of Temperature and Humidity on the Performance and Physiology of Laying Hens // Animals (Basel). 2020. No. 11 (1). Article number.56. DOI:https://doi.org/10.3390/ani11010056.
10. Broyler. Rukovodstvo po vyraschivaniyu [Elektronnyy resurs]. URL: https://www.winmixsoft.com/files/info/HUBBARD_rus.pdf (data obrascheniya: 25.11.2022).
11. Ferraboschi P., Ciceri S., Grisenti P. Applications of Lysozyme, an Innate Immune Defense Factor, as an Alternative Antibiotic // Antibiotics (Basel). 2021. No. 10 (12). Article number 1534. DOI:https://doi.org/10.3390/antibiotics10121534.
12. Song B., Tang D., Yan S., Fan H., Li G., Shahid M. S., Mahmood T., Guo Y. Effects of age on immune function in broiler chickens // Journal of animal science and biotechnology. 2021 No. 12 (1). Article number 42. DOI:https://doi.org/10.1186/s40104-021-00559-1.
13. Ismiraj M. R., Arts J. A. J., Parmentier H. K. Maternal Transfer of Natural (Auto-) Antibodies in Chickens // Poultry science. 2019. No. 98 (6). Rr. 2380-2391. DOI:https://doi.org/10.3382/ps/pez017.
14. Wang S., Mahfuz S., Song H. Effects of Flammulinavelutipes stem base on microflora and volatile fatty acids in caecum of growing layers under heat stress condition // Brazilian Journal of Poultry Science. 2019. No. 21 (4). DOI:https://doi.org/10.1590/1806-9061-2019-0989.
15. Barrett N. W., Rowland K., Schmidt C. J., Lamont S. J., Rothschild M. F., Ashwell C. M., Persia M. E. Effects of acute and chronic heat stress on the performance, egg quality, body temperature, and blood gas parameters of laying hens // Poultry science. 2019. No. 98. Rr. 6684-6692. DOI:https://doi.org/10.3382/ps/pez541.
16. Kim D. H., Lee Y. K., Lee S. D., Kim S. H., Lee S. R., Lee H. G., Lee K. W. Changes in production parameters, egg qualities, fecal volatile fatty acids, nutrient digestibility, and plasma parameters in laying hens exposed to ambient temperature. Front // Frontiers in Veterinary Science. 2020. No. 7. Article number 412. DOI:https://doi.org/10.3389/fvets.2020.00412.
