Changes over life-time in morphometric and metabolic variables in the long-lived freshwater mussel Diplodon chilensis

YUSSEPPONE M.S.; LOMOVASKY B.J.; LUQUET C.; ROCCHETTA I.; RÍOS DE MOLINA M.C.

Valencia

Congreso; Oxygen Club of California World Congress; 2015

The Oxigen Group of California

Diplodon chilensis is a long-lived freshwater mussel, the most abundant in the Patagonian region, Argentina, with a MLSP of 90. Biomarkers of oxidative stress and antioxidant defense system were investigated in digestive gland (DG) and gonad tissues, along with morphometric variables, in relation to chronological age and sex. The von Bertalanffy growth model describes the individual growth (L∞ = 72.01 mm; k = 0.14 year-1; Agemax = 73 years old). Several antioxidant and oxidative stress parameters (superoxide dismutase (SOD) activity, glutathione (GSH) level and oxidative damage to proteins) remain constant through life in both tissues, while catalase (CAT) and GST activities, and lipid peroxidation decrease until 24 - 27 years, to remain fairly stable (mostly in gonads) or increase slowly mostly in DG afterwards. The timing of these age-related changes is coincident with the age estimated (28 years) from the lower Confidence limit (Cl) for L∞ (69.97 mm), at which the bivalves would reach their minimum growth rate. A continuously increase in DG mass with age was recorded.The biochemical composition analysis showed that DG protein and lipid concentrations remained unchanged, while glycogen concentration increased until 30 y and then decreased. In gonad tissue, Gonad Mass (GM) increased also with age, following different patterns in females and males and was significantly higher in males. Total lipid content increased with age in gonads while proteins decreased. Besides GM and gonad glutathione-S-transferase (GST) activity (higher in females), no differences were found between sexes for any of the variables analyzed in this study. The role of oxidative stress in this species could contribute to understand its longevity. Considering its wide distribution in Argentina and Chile, with abundant populations in a great variety of lake and river environments becomes a promising model for aging.