Immunomodulatory effects of <i>Terfezia claveryi</i> extract against experimental <i>Hysterothylacium thalassini</i> infection in mice

Fish are an essential source of high-quality protein and micronutrients. Yet parasitic infections often compromise safety. Anisakid nematodes, such as <i>Hysterothylacium thalassini</i>, are widely distributed in marine fish, including the greater lizardfish <i>Saurida tumbil</i>, and pose potential risks to human health. Infection with anisakid larvae is associated with oxidative stress, inflammatory responses, immune dysregulation, and apoptosis. Natural products rich in bioactive compounds may provide effective protection against these pathological effects. Desert truffles (<i>Terfezia claveryi</i>) possess well-documented antioxidant and immunomodulatory properties, but their activity against anisakid infections remains poorly characterized. This study investigated the protective effects of <i>Terfezia claveryi</i> extract (TCE) against experimental <i>H. thalassini</i> third-stage (L3) larval infection in a murine model, focusing on antioxidant activity, hematological changes, splenic immune responses, and Caspase-3-mediated apoptosis. TCE was prepared by methanol-water extraction, and its antioxidant potential was evaluated using the FRAP, DPPH, and ABTS assays. Forty male C57BL/6 mice were allocated into eight groups, including uninfected controls, TCE-treated mice, and mice infected with fresh, thermal, or frozen L3 larvae, with or without TCE treatment. After 14 days, hematological indices, spleen index, and Caspase-3 expression were assessed using immunohistochemistry, quantitative reverse transcription PCR, and ELISA. Larval infection induced significant anemia, leukocytosis, splenomegaly, and marked upregulation of Caspase-3, indicating enhanced oxidative stress and apoptotic activity. TCE administration significantly improved hemoglobin, red blood cell, hematocrit, platelet, and white blood cell values and reduced the spleen index. Caspase-3 expression was downregulated at both mRNA and protein levels, with ELISA-confirmed reductions in apoptotic markers (from 1178.37 ± 64.94 pg/mL in untreated infected mice to 744.79 ± 65.82 pg/mL following treatment). In conclusion, TCE exhibits potent antioxidant, anti-apoptotic, and immunomodulatory effects that alleviate <i>H. thalassini</i>-induced hematological and splenic alterations, supporting its potential as a natural therapeutic candidate against fishborne parasitic infections globally.