M. Strateva
Department of Veterinary Anatomy, Histology and Embryology, Faculty of Veterinary Medicine, Trakia University, 6000 Stara Zagora, Bulgaria
(Manuscript received 1 January 2026; accepted for publication 22 February 2026)
*e-mail: mariyana.strateva@trakia-uni.bg
Abstract. The objective of the present research was to apply a histological method to study the condition of the muscles in frogs (Hoplobatrachus rugulosus) offered on the Bulgarian market, frozen at -18°C for a period of 4 months. Material from 24 frogs, taken from Triceps femoris, Semimembranosus, Gastrocnemius and Peroneus, was fixed in 10% buffered formalin for 72 hours. After fixation, the samples were embedded in paraffin according to a standard protocol and stained with hematoxylin-eosin and Masson’s trichrome method. Morphological analysis revealed structural changes affecting all studied muscle groups. The histological evaluation revealed irreversible and significantly manifested damage to both the muscle fibers and the accompanying connective tissue. These findings are important for determining the quality of frozen frog meat offered on the market, and to emphasize the need to control the conditions and duration of freezing.