The effect of fixatives in the quantification of morphological lipofuscin as an age index in crustaceans

The role of fixation in studies using histological techniques to measure lipofuscin as an age indicator was evaluated. Four fixatives were used: Bouin, 10% buffered saline formaldehyde, Davidson and San Felice. The species used was the Norway lobster (Nephrops norvegicus). Similar sized males, with a maximum carapace length difference of less than 10 mm were used and attributed randomly to each treatment. Results showed that San Felice and Davidson were not appropriate for lipofuscin studies. Bouin and 10% formaldehyde produced the best results in terms of tissue quality and lipofuscin granule brightness. This work suggests that Bouin can be a substitute of formaldehyde in lipofuscin studies, in particular in situations when other structures, such as gonads, are needed for parallel or complementary studies.