Effects of Breed on Reproductive Efficiency of Two Most Popular Snails [Archachatina marginata (S) and Achatina achatina (L)] in Nigeria

The effects of breed on the reproductive efficiency of the two most popular snail breeds [Archachatina marginata (S) and Achatina achatina (L)] in Nigeria were evaluated. Sixty snails each of the Archachatina marginata and the Achatina achatina breeds consisting of 30 black-skinned and 30 white-skinned ectotypes each of A. marginata and A. achatina were used. The snails were randomized into three mating groups; black-skinned x black-skinned (BS X BS), white-skinned x white-skinned (WS X WS) and black-skinned x white-skinned crossbred (BS X WS) and replicated five times in the randomized complete block design. Results of the study on mean egg traits revealed a highly significant (P<0.01) mean egg weight and mean egg length at lay between the black-skinned purebred and the black-skinned x white-skinned crossbred. The mean egg width also indicated highly significant (P<0.001) differences between the black-skinned purebreds of A. marginata and A. achatina. The variations in mean egg traits between the two breeds and the crosses of their ectotypes in this study may indicate variation in genetic composition of the snails. Results of hatchling traits evaluated showed that there also was a highly significant difference (P<0.001) in mean hatchling weights between the black-skinned purebreds of A. marginata and A. achatina. The hatchlings mean shell length results also showed significant differences (P<0.05) between the black-skinned purebreds and the crossbreds mating groups in the two breeds. The percent variability results indicated that high and low percent egg weight variability existed between the black-skinned purebred and the crossbred mating groups of the A. marginata and A. achatina at lay. There also was high and low percent variability for egg weight at hatch for the black-skinned purebred and the black- and white- skinned crossbred mating groups. The variability observed among the traits of hatchlings was due to genetic factors and could mean that their improvement will not be markedly influenced by the environment. The results of correlation among traits revealed positive and highly significant phenotypic correlation (rp) within egg and hatchling traits for the two snail breeds studied. The correlation could suggest that there are direct relationships between the traits, and that selection for one trait will lead to improvement in the other trait. It is recommended that intensive domestication and massive production of A. marginata be embarked upon since it appears to have higher potentials to meet the animal protein supply of the populace than A. achatina. This is because of its larger size.