Comparative Differentiation of Morphometric Traits and Body Weight Prediction of Giant African Land Snails with Four Whorls in Niger Delta Region of Nigeria

Abstract

Four hundred (400) adult black-skinned snails, two hundred (200) each of Archachatina marginata and Achatina fulica with weight ranging from 50.42 g to 198.84 g and from 100.10 g to 184.00 g for A. marginata and A. fulica respectively selected based on active appearance, number of whorls and no injury on the foot and/or shell of a base population from a population gathered in the wild within the Niger Delta region were used for the study. Data collected on the selected snails were used to evaluate phenotypic correlations and multiple regression functions which were used for predicting body weights from quantitative traits. Results obtained from the study showed that A. fulica snails with 4 whorls are genetically heavier than A. marginata snails with 4 whorls. This is because there was large and significantly different (P<0.001) disparity in values of measured quantitative traits (mean body weights) among the two breeds. The results of phenotypic correlations among quantitative traits of the two breeds indicated positive, strong and very high significant (P<0.001) correlation coefficients (r p ) between body weight and all body components studied. Whereas for A. fulica snails, there were positive but lower significant (P<0.05) phenotypic correlation coefficients (r p ) between body weight and some body components studied. In fact, there were no significant (P>0.05) phenotypic correlation coefficients (r p ) between shell length and shell 'mouth' width (r = 0.250) and between shell 'mouth' length and shell 'mouth' width (r = 0.187) for A. fulica snails. The prediction equations evolved for body weights of growing snails with 4 whorls using quantitative traits from A. marginata and A. fulica indicated that these quantitative traits, namely; shell length, shell width, shell 'mouth' length and shell 'mouth' width best predicted body weight for A. marginata and A. fulica snails with 4 whorls. The quantitative or phenotypic traits of the two breeds of snail studied could be chosen to differentiate as well as characterize growing snails in the Niger Delta region of Nigeria.

Genetic and phenotypic variations in egg shell colour of two ectotypes of Giant African Land Snail (Archachatina marginata var. saturalis)

“…A. marginata is the second largest snail and most popular breed of snail kept and reared in Nigeria (Venette and Larson, 2004;Okon et al, 2012b). A. marginata produces a peristome with a reflected lip and reaches maturity 2 to 4 months later than A. fulica (Raut and Barker, 2002).…”

Phenotypic Correlations and Body Weight Prediction of Two Ectotypes of Giant African Land Snails (Archachatina maginata, Swain.) Based on Number of Whorls in Calabar, Nigeria

“…This may be due to the positive, strong and closely correlated responses of body weight with the phenotypic traits used in the predictions. However, these results of prediction equations agreed with that of [24] for A. marginata and A. fulica with 4 whorls, but do not agree with [23] and [25] for A. marginata snails because of age differences and number of phenotypic traits used in the equation. Authors [23] could not closely predict hatching (juvenile) body weight of A. marginata snails using shell length and shell width.…”

Comparison of growth and heterosis of body parameters of two varieties of snail [Archachatina marginata (Swainson1821)] and their crosses reared under tropical conditions

“…Breed types, according to Okon et al (2012a), have a marked effect on performance and production of snails than all other factors considered. Thus, these authors asserted that the performance of any animal is dependent upon the inherent genetic make-up and the environment in which it is raised.…”

“…ovum and A. marginata var. saturalis have been extensively done by Ibom et al (2011), Ibom and Okon (2012), Okon et al (2008Okon et al ( , 2012aOkon et al ( , 2012bOkon et al ( , 2014, Imran and Alarape (2012), Isah and Peter (2012), Jayeola et al (2013), Onuoha (2014), Oyeagu et al (2015), Fayenuwo et al (2015), Egbu et al (2015), and Ejidike and Oladipo (2015). Growth measured in terms of body weight gain (BWG) is the most widely used growth index from birth to maturity (Okon and Ibom, 2012).…”