Analysis of the age dynamics of morphological parameters of rainbow trout blood in aquaculture conditions

Rainbow  trout  (Parasalmo  mykiss)  is  a promising  type  of  aquaculture  with  one  of the  largest  production  potentials  in  Russia. The  Republic  of  Karelia  currently  holds  a leading position in cage trout farming, supplying more than 80% of commercial trout produced  in  the  Russian  Federation  to  the domestic  market.  Increasing  the  output  of aquaculture products is an important condition  for  supporting  Russia's  food  security and  ensuring  the  socio-economic  development of the regions. Given the rate of spread of  diseases  in  trout,  the  rapid  change  of phases  of  the  immune  response  in  fish,  as well as the location of farms in sparsely populated remote areas, research remains particularly  relevant  on  the  search  for  sensitive molecular  methods  of  rapid  diagnosis  that identify the pathogen in the early stages of the  infectious  process  to  develop  rational treatment  and  prevention  tactics.  The  purpose of the presented study was to monitor the condition of rainbow trout in ontogenesis based on hematological studies. During the study, significant (P<0.05) differences were noted in the number of red blood cells and the total number of white blood cells (TLC), depending on the sex of the fish. In addition, clearly  distinguishable  morphometric  features  were  also  seen  among  erythrocytes, leukocytes  (lymphocytes,  neutrophils  and monocytes)  and  platelets.  Thus,  during  the monitoring of the physiological state of rainbow trout in aquaculture conditions, it was found  that  the  condition  of  the  fish  body worsens with age, which affects the morphological parameters of the blood. The hemoglobin content varied widely. A decrease in its  concentration  indicates  acute  blood  loss and hemolytic anemia. The results obtained are  the  basis  for  the  development  of  new promising natural adaptogens that normalize the physiological state of fish and ensure the production of biosafety trout products.

1. Chatzifotis S., Muje P., Pavlidis M., Ågren J., Paalavuo M., Mölsä H. Evolution of tissue composition and serum metabolites during gonadal development in the common dentex Dentex dentex) // Aquaculture. 2004. No. 236. pp. 557-573.

2. Chen H., Yuan G., Su J., Liu X. Hematological analysis of Ctenopharyngodon idella, Megalobrama amblycephala and Pelteobagrus fulvidraco: Morphology, ultrastructure, cytochemistry and quantification of peripheral blood cells // Fish Shellfish Immunol., 2019. No. 90. Pp. 376-384.

3. Fazio F. Fish hematology analysis as an important tool of aquaculture: a review // Aquaculture, 2019. No. 500. pp. 237-242.

4. Jansson M., Olsson H., Pettersson K/ Phosphatases, origin, characteristics and function in lakes // Hydrobiologia. 1988. Vol. 170. P. 157-175

5. Nabi N., Ahmed I., Wani G.B. Hematological and serum biochemical reference intervals of rainbow trout, Oncorhynchus mykiss cultivated in Himalayan aquaculture: Morphology, morphometrics and quantification of peripheral blood cells // Saudi Journal of Biological Sciences, 2022. Vol. 29 (4). p. 294.

6. Valenzuela A.E., Silva V.M., Klempau A.E. Effects of different artificial photoperiods and temperatures on haematological parameters of rainbow trout (Oncorhynchus mykiss) // Fish Physiol. Biochem., 2008. No. 34. pp. 159-167.

7. Zhiteneva L. D. Atlas of normal and pathologically altered fish blood cells / L. D. Zhiteneva, T. G. Poltavtseva, O. A. Rudnitskaya. Rostov-on-Don, 1989. 112 p.

8. Zubrikhina G. N., Blindar V. N., Timofeev Y. S. Theory and practice of laboratory hematology research: textbook. M.: GEOTAR-Media, 2020. - 288 p.

9. Ivanova, N.T. Atlas of fish blood cells (comparative morphology and classification of shaped elements of fish blood). M.: Light and food industry, 1982. 184 p.

10. Ivanter E. V., Korosov A.V. Elementary biometrics, Petrozavodsk: PetrSU Publishing House, 2005. 104 p.

11. Study of ecosystems of fishery reservoirs, collection and processing of data on aquatic biological resources, technology and technology of their extraction and processing. Issue 5. Instructions for observers (ichthyology). - M.: VNIRO Publishing House, 2006. - 84 p.

12. Kraynyuk V. N. Dynamics of liver and spleen indices in roach Rutilus rutilus (L., 1758) (Cyprinidae) from the K. Satpayev canal system in winter and prespawning periods // Actual problems of humanities and natural sciences. 2016. - No. 1. - pp. 44-47.

13. Mamontov, I. Yu. Russian trout farming and development prospects / I. Yu. Mamontov // Science without borders. – 2021. – №1 (53). – Pp. 55-59.

14. Menshikov, V. V. Clinical diagnosis — laboratory fundamentals. / V.V. Menshikov – M.: Publishing house "Labinform", 1997. – 320 p.

15. Standards for the quality of water bodies of fisheries importance, including standards for maximum permissible concentrations of harmful substances in the waters of water bodies of fisheries importance. - M.: VNIRO Publishing House, 2011. - 257 p.

16. Pishchenko E. V. Hematology of freshwater fish: Textbook. Novosibirsk: Novosibirsk State Agrarian University. univ. 2003. 48 p.

17. Polistovskaya, P. A. The influence of zinc on hematological parameters of carp / P. A. Polistovskaya, L. Y. Karpenko, A. I. Enukashvili [et al.] // Scientific notes of the Kazan State Academy of Veterinary Medicine named after N.E. Bauman. – 2019. – Vol. 240. – No. 4. – pp. 151-154.

18. Pomerantsev, D. A. Topical issues of the state of aquaculture in the Leningrad region / D. A. Pomerantsev, N. A. Semenenko // The role and place of innovations in the field of agro-industrial complex: materials of the All-Russian (national) scientific and practical conference dedicated to the 100th anniversary of the birth of Professor A.A. Sysoev, Kursk, November 20, 2019 of the year. – Kursk: Kursk State Agricultural Academy named after Professor I.I. Ivanov, 2020. – pp. 146-149.