Blood picture and immune response under high-density transport conditions in common carp

The aim of the work was to evaluate the effect of stress during transportation with high planting density on the physiological state and hematological parameters of yearling carp (Cyprinus carpio).

Methods: the experiment was conducted on two groups of fish (average weight 77,4 ± 27,7 g) transported in sealed bags for 24 hours. The control group was transported with a density of 175 g/l without air conditioning, the experimental group with a density of 368 g/l with the addition of an industrial water conditioner (1,25 ml/l). Blood was taken from the tail vein three times for analysis: one week before the experiment, immediately after transportation, and after 6 hours of recovery. The leukocyte formula, erythrogram, SPK index (total cell count) and morphometry of erythrocytes were determined by light microscopy of stained smears.

Novelty: it has been shown for the first time that the use of a specialized water conditioner makes it possible to safely increase the density of carp planting during transportation by more than 2 times (up to 368 g/l), minimizing stress-induced changes in hematological parameters compared to the standard regime.

Results: transportation caused an acute stress response in both groups: an increase in the proportion of neutrophils and a decrease in the proportion of lymphocytes. However, in the experimental group with air conditioning, these changes were significantly less pronounced (a decrease in lymphocytes to 81,0% versus 70,0% in the control). 6 hours after transportation, the hematological parameters of the fish in the experimental group recovered to their initial level faster and more completely than in the control group.

Practical significance: the data obtained proves the effectiveness of using water conditioners to increase carp stocking density during transportation without compromising their physiological condition. The identified hematological markers (neutrophil/lymphocyte ratio, SPK index) can be used for rapid assessment of stress levels in fish, which will optimize logistics in aquaculture and reduce economic losses.

1. Kandybin A. A., Bubunets E. V. 2025. Dynamics of the oxygen regime during the transportation of cyprinid fish in sealed containers // Research of Young Scientists in the Implementation of Priorities for Scientific and Technological Development in Animal Husbandry. Coll. of abstr. of the Youth Scientific Conference. Dubrovitsy. P. 111–112. (In Russ.)

2. Mikrjakov V. R., Balabanova L. V., Mikrjakov D. V. 2007. Influence of transportation on structure leukocytes of peripheral blood carp Cyprinus carpio L. // Problems of fisheries. V. 8. № 2(30). P. 209–214. (In Russ.)

3. Nikitenko A . I., Pronina G. I., Orlov A . M., Artemenkov D. V., Stroganov A. N., Belyaev V. A. 2022. On the peripheral blood of three fish species with different ecology (Scombridae and Berycidae) // Izvestiya RAS. Ser. Biological. № 6. P. 661–667. (In Russ.)

4. Orlov Yu.I., Kruzhalina E. I., Averina I. A. Ilyicheva T. I. 1974. Transportation of live fish in hermetic containers: a reference guide. Moscow: Pishchevaya promyshlennost’. 97 p. (In Russ.)

5. Pishchenko E. V., Moruzi I. V. 2022. Global trends and prospects for carp farming // Prospects and Opportunities of the Industry. P. 164–177. (In Russ.)

6. Pronina G. I., Koryagina N.Yu. 2017. Methodology for physiological and immunological assessment of aquatic organisms. Saint Petersburg: Lan’. 96 p. (In Russ.)

7. Adah D. A., Adah A. S., Nwonuma C. O., Olaosebikan B., Oyekunle T. 2023. The Ameliorative effects of ascorbic acid on hematological and water quality parameters following a 100 km transportation of adult Clarias gariepinus // Media Kedokteran Hewan. V. 34. № . 1. P. 13–26. DOI: 10.20473/mkh.v34i1.2023.13‑26

8. Burgos-Aceves M.A., Lionetti L., Faggio C. 2019. Multidisciplinary haematology as prognostic device in environmental and xenobiotic stress-induced response in fish // Science of The Total Environment. V. 670. P. 1170–1183. DOI: 10.1016/j.scitotenv.2019.03.275.

9. Davis A. K., Maney D. L., Maerz J. C. 2008. The use of leukocyte profiles to measure stress in vertebrates: a review for ecologists // Functional Ecology. V. 22. № 5. P. 760–772. DOI: 10.1111/j.1365‑2435.2008.01467.x.

10. Dhabhar F. S. 2002. A hassle a day may keep the doctor away: stress and the augmentation of immune function // Integrative and Comparative Biology. V. 42. № 3. P. 556– 564. DOI: 10.1093/icb/42.3.556.

11. Dobšíková R., Svobodová Z., Bláhová J., Modrá H., Velíšek J. 2009. The effect of transport on biochemical and haematological indices of common carp (Cyprinus carpio L.) // Czech Journal of Animal Science. V. 54. № 11. P. 510– 518. DOI: 10.17221/52/2009‑CJAS

12. Eissa E. S.H., Okon E. M., Abdel-Warith A.W.A., Younis N. A., Gewaily M. S., Mahmoud S. F., El-Deriny M.M.E., Ahmed S. A., Mahmoud M. A., Dawood M. A.O. 2024. In-water Bacillus species probiotic improved water quality, growth, hemato-biochemical profile, immune regulatory genes and resistance of Nile tilapia to Aspergillus flavus infection // Aquaculture International. V. 32. P. 7087–7102. DOI: 10.1007/s10499‑024‑01503‑6.

13. Ellis T., North B., Scott A. P., Bromage N. R., Porter M., Gadd D. 2002. The effects of crowding and exercise on the immune response of rainbow trout (Oncorhynchus mykiss) // Fish & Shellfish Immunology. V. 12. № 3. P. 239–254. DOI: 10.1006/fsim.2001.0368

14. Gomes L. C., Araujo-Lima C.A.R.M., Roubach R., Chippari-Gomes A.R., Lopes N. P. 2003. Effect of Fish Density During Transportation on Stress and Mortality of Juvenile Tambaqui Colossoma macropomum // Journal of the World Aquaculture Society. V. 34. № 1. P. 76–84. DOI: 10.1111/j.1749‑7345.2003.tb00041.x.

15. Klak K., Maciuszek M., Pijanowski L., Marcinkowska M., Homa J., Verburg-van Kemenade B. M.L., Rakus K., Chadzinska M. 2024. Evolutionarily conserved mechanisms regulating stress-induced neutrophil redistribution in fish // Frontiers in Immunology. V. 15. P. 1330995. DOI: 10.3389/fimmu.2024.1330995

16. Luz R. K., Favero G. C. 2024. Use of Salt, Anesthetics, and Stocking Density in Transport of Live Fish: A Review // Fishes. V. 9. № 7. P. 286. DOI: 10.3390/fishes9070286.

17. Martemyanov V. I. 2013. Patterns of changes in sodium content in plasma and erythrocytes of freshwater fish at stress // Journal of Ichthyology. V. 53. № 3. P. 220–224. DOI: 10.1134/s0032945213020094.

18. Martinez-Porchas M., Martinez-Cordova L.R., Ramos-Enriquez R. 2009. Cortisol and glucose: Reliable indicators of fish stress? // Pan-American Journal of Aquatic Sciences. V. 4. № 2. P. 158–178.

19. Megarani D. V., Hardian A . B., Arifianto D., Santosa C. M., Salasia S. I.O. 2020. Comparative Morphology and Morphometry of Blood Cells in Zebrafish (Danio rerio), Common Carp (Cyprinus carpio carpio), and Tilapia (Oreochromis niloticus) // Journal of the American Association for Laboratory Animal Science. V. 59. № 6. P. 673–680. DOI: 10.30802/AALAS‑JAALAS‑20‑000013.

20. Schreck C. B., Tort L. 2016. The concept of stress in fish // Fish Physiology / C. B. Schreck, L. Tort, A. P. Farrell, C. J. Brauner eds. V. 35. London: Academic Press. P. 1–34. DOI: 10.1016/B978‑0‑12‑802728‑8.00001‑1

21. Shu J. J., Heuer R. M., Hannan K. D., Stieglitz J. D., Benetti D. D., Rummer J. L., Grosell M., Brauner C. J. 2022. Enhanced oxygen unloading in two marine percomorph teleosts // Comparative Biochemistry and Physiology Pt A: Molecular & Integrative Physiology. V. 264. P. 111101. DOI: 10.1016/j.cbpa.2021.111101.

22. Thomas S., Perry S. F. 1992. Control and consequences of adrenergic activation of red blood cell Na+/H+ exchange on blood oxygen and carbon dioxide transport in fish // Journal of Experimental Zoology. V. 263. № 2. P. 160–175. DOI: 10.1002/jez.1402630206.

23. Wang L. G., Liu M. Q., Xie X. D., Sun Y. B., Zhang M. L., Zhao Y. et al. 2023. Effects of different water quality regulators on growth performance, immunologic function, and domestic water quality of GIFT tilapia // PLoS ONE. V. 18. № 8. P. e0290854. DOI: 10.1371/journal.pone.0290854.

24. Wendelaar Bonga S. E. 1997. The stress response in fish // Physiological Reviews. V. 77. № 3. P. 591–625. DOI: 10.1152/physrev.1997.77.3.591

25. Witeska M., Kondera E., Lugowska K., Bojarski B. 2022. Hematological methods in fish — Not only for beginners // Aquaculture. V. 547. P. 737498. DOI: 10.1016/j.aquaculture.2021.737498.