Immuno-endocrine alterations and oxidative stress induced by commercial formulations of pesticides in the tegu lizard (Salvator merianae).

Recent research has shown the risk of environmental contamination by pesticides in Argentina. Salvator merianae is considered as "sentinel species" for monitoring their effects. We intended to investigate growth, immunological and endocrine functions, and oxidative stress in S. merianae exposed to two commercial brands of the herbicide glyphosate: Roundup and Panzer Gold, as well as, to two insecticides: chlorpyrifos, and cypermethrin. Our results showed a higher increase in growth in animals exposed to Roundup and chlorpyrifos and a lower increase in those exposed to Panzer Gold. Higher total leukocyte and lymphocyte count values were observed in lizards exposed to Panzer Gold. The heterophils/lymphocytes ratio decreased in all treated animals. Regarding lobularity index, natural antibodies titers, and complement system activity values, lizards exposed to cypermethrin had higher values. Low corticosterone levels were observed in animals exposed to Roundup. Our results reveal different toxic effects of pesticides contributing to the knowledge of the pesticides' potential deleterious impact in the habitat of S. merianae.

Ultraviolet radiation on innate immunity and growth of broad-snouted caiman (Caiman latirostris): implications for facilities design.

Sunlight is a key environmental factor in almost all ecosystems, and it is necessary for many physiological functions. Many vertebrates require ultraviolet (UV) radiation to perform different physiological processes. Artificial light is used to supplement UV in captive animals, through appropriate photoperiods and UV wavelengths. Previous studies reported that repeated exposure to artificial UV radiation may cause damage to the immune system. Taking into account the importance of UV effects and the serum complement system, the relationship between them was investigated. The study lasted 90 days and was carried out in plastic chambers. Ninety six broad-snouted caiman (C. latirostris) were assigned to four treatment groups with two replicates each: total darkness (TD), 8 hr per day (8 hr) and 16 hr per day (16 hr) of artificial UV/visible light exposure, and normal photoperiod of natural light (NP). Snout-vent length was measured to determine animal growth. Hemolytic assays were performed to evaluate the effects of artificial UV/visible light, TD, and NP on the serum complement system. Results showed that animals grew more in the NP group. The capacity of C. latirostris serum to hemolyze sheep red blood cells was higher in the NP group than when they are maintained in constant light-dark cycles (8 and 16 hr) or in TD. These data demonstrate that artificial UV should be considered as a potential hazard for captive crocodilians if it is not properly managed, and this should be taken into account in the general design of facilities for reptilian husbandry.