SHORT TERM FASTING AND IMMUNE SYSTEM FUNCTION IN THE BROAD SNOUTED CAIMAN, Caiman latirostris

LOPEZ, LEANDRO ERNESTO; MOLINA MARINO, LUCIANA MARIEL; GONTERO FOURCADE, MANUEL; CAVIEDES VIDAL, ENRIQUE

San Francico

Congreso; 2013 Annual meeting Society for Integrative and Comparative Biology; 2013

Society for Integrative and Comparative Biology

Caimans experience different environmental pressures during their life, such as decreased availability of food resources. Since a reduction of energy intake at early ages may result in a trade-off between growth and immune function, we studied immune, metabolic and stress parameters of young caimans subjected to short term fasting. Fifteen 8-month old caimans were divided in 2 gropus: A) with food ad lib (F+, N=8) B) fasted (F-, N=7) for 60 days. Blood was collected to perform the following assays: whole blood for hematocrit and heterophil/lymphocyte (H/L) index; plasma for biochemical parameters, total IgG (humoral immunity) and complement hemolytic activity (CHA) (innate immunity); blood cells for Heat Shock Protein 60, 70 and 90 (HSPs) (stress biomarkers) assessment. After fasting, the F- group lost 12% of their initial body-mass versus a 5% loss of the F+ group. Hematocrit and H/L index were not different between treatments. The four biochemical parameters showed significant differences between groups. No differences were apparent for the IgG index, though CHA exhibited a decreasing trend in fasted caimans. None HSPs analyzed showed differences in their expression levels. These results show that even after a significant period of fasting that alters their metabolic status, young growing-caimans can endure an energy shortage without altering their immune parameters. This is a key fact for survival considering they must face highly pathogenic environments and food scarcity in nature. Funded by PICT97-01320 to EC-V