The Antioxidant Role of a Taurine-Enriched Diet in Combating the Immunotoxic and Inflammatory Effects of Pyrethroids and/or Carbamates in Oreochromis niloticus

SIMPLE SUMMARY: Insecticidal pollution of surface waters is known to hurt the growth, survival, and breeding of aquatic animals. Different types of insecticides are known to be toxic to different aquatic organisms, particularly to fish species. In different types of wastewater, the fishes get exposed to different mixtures of insecticides. The current study hypothesized that co-exposure to lambda-cyhalothrin (LCT) and methomyl (MTM) insecticides might be more harmful due to duplicated effects than exposure to either one of them at a time. Oreochromis niloticus was the target fish in this study. The combative roles of taurine (TUR) against LCT and MTM exposures were evaluated. In the present work, exposure of O. niloticus to LCT and/or MTM exhibited adverse effects on immunological parameters, including leukocyte count, complement 3 concentration, antioxidant enzyme concentrations, and mRNA expression for cytokines (TNF-α and IL-1β) and chemokines (CC and CXC). This study also elucidated the more severe toxic effect of LCT than exposure to MTM in O. niloticus fish. The immune response and growth performance of O. niloticus showed marked improvements when provided a 1% TUR-enriched supplement. ABSTRACT: Indiscriminate use of insecticides is a major concern due to its ubiquitous occurrence and potential toxicity to aquatic animals. This study investigated the adverse effects of lambda-cyhalothrin (LCT; C(23)H(19)ClF(3)NO(3)) and methomyl (MTM; C(5)H(10)N(2)O(2)S) on immune system modulations and growth performance of juvenile fishes. The supportive role of a taurine (TUR; C(2)H(7)NO(3)S)-supplemented diet was also evaluated. Juvenile O. niloticus fishes were exposed to LCT (0.079 µg/L), MTM (20.39 µg/L), or both in water and were fed on a basal diet only or taurine-supplemented basal diet. Exposure to LCT and MTM retarded growth and increased mortality rate. LCT and MTM reduced antioxidant enzyme activities (superoxide dismutase and glutathione peroxidase) and innate and humoral immunity but upregulated interleukin and chemokine expressions. Moreover, exposure to LCT and MTM elevated 8-OHdG levels and increased the mortality of Oreochromis niloticus after the experimental bacterial challenge. The TUR-enriched diet enhanced antioxidant enzymes and acted as a growth promoter and anti-inflammatory agent. TUR can modify innate and adaptive immune responses. Furthermore, TUR supplementation is a beneficial additive candidate for mitigating LCT and MTM toxicities mixed with O. niloticus aquafeed.