Traditional utilization and biochemical composition of six mollusc shells in Nigeria
The shells of molluscs protect them from physical damage, predators and dehydration. We studied various local uses of shells and their biochemical properties in Abeokuta, Nigeria. A standard structured questionnaire about use was applied to 100 snail and herb sellers and shells from 120 adult individuals of Archachatina marginata, Achatina achatina, Achatina fulica, Littorina littorea, Meretrix lusoria and Merceneria mercenaria were evaluated for their mineral components (Ca2+, Fe2+, Mg2+, Na+, Zn+, P+, K+) and proximate composition (crude protein, ash, fibre, crude fat and carbohydrate) using standard methods. Properties against fungi and bacteria isolates were also tested. These shells are used for bleaching, brushing, abrasion and others. The weight of the shells varied from 0.5g (L. littorea) to 25.00g (A. marginata) and thickness from 0.46mm in M .lusoria to 5.35mm in M. mercenaria. We found no inhibitory effect against fungi and bacterial isolates. The molluscs are high in carbohydrates (83.54-92.76g/100g) and low in protein (0.16-0.38g/100g). The fat content ranged between 0.42g/100g and 0.82g/100g, and ash between 2.14g/100g and 9.45g/100g. Ca2+ was the most abundant (10.25-96.35mg/g) while K+ was the least abundant (0.3-0.7mg/g) (p<0.05). Active ingredients of these shells can be used in the feed and construction industries.
Keywords: shell, mollusc, proximate analysis, antimicrobial, antifungal, uses