ABSTRACT

The purpose of this study is to look into the effect of different calcium sources on the shell formation of snail. A total of 60 growing snails were purchased from a reputable snail farm, the snails were divided into three groups. Group A control were fed with bone meal and Oyster shell, Group B were fed with Bone. The data collected was on weekly weight gain and total calcium consumed by each group. Oyster shell is the best calcium source for snail, it help, snail to develop hard shell and also contributes to their calcium consumption.

CHAPTER ONE

INTRODUCTION

BACKGROUND OF THE STUDY

Snail are one of the earliest known types of animals in the world. There is evidence that they evolved more than 600million years ago. They are able to adapt to a variety of living condition and they don’t require large amount of food. All snails are classified as molluskas because of the hard shell protect their bodies.

Snail is a member of the molluscan class gastropoda that have a spirally coiled shells. It includes sea snails, land snails and fresh water snails. It belongs to the Kingdom – Animalia, Phylum- mollusca, Class- castropoda, Subclass- pulmonata, Order- stylommatrophora, Family- helicidea.

The word snail without any qualifier is however applied to the land snail than those in the sea or fresh water. Snail like animal that naturally lack a shell or have only an internal shell are often called slugs and land species that have only a very small shell are called semi slugs.

The average life span of a snail is approximately 15years. However it is believed that some species live up to 25years depending on their habitat. It takes about 2 years for snails to mature. The adult brown garden snails lay an average 80 spherical, pearly white eggs at a time into hole in the soil. They can also lay eggs up to 6 times a years.

Snail that respire using lung belong to the group pulmonate, while those with gills form a paraphyletic group. In other words snail with gills are divided into a number of  taxonomic groups that are not very closely related, Snail with lungs and with gills have diversified widely enough over geological time that a few species with a lung can be found in fresh water and a few species with lung can be found in a sea.

Snails can be found in a very wide range of environment including ditches, deserts, and the abyssal depths of the sea. Although many people are familiar with terrestrial snails, land snails are in the majority. Marine snails are in the majority of snail species and have much greater diversity and a greater biomass.

Numerous kinds of snails have thousands of microscopic tooth – like structures located on a ribbon like tongue called radula. The radula works like a file, ripping the food into small pieces.

The mouth of the snail is found at the bottom of the head in close proximity to the tentacles it has one or two sets of tentacle that are on top of  head, the number of pairs will depend on the species you are describing. There is a foot on a snail as well that allow it to move forward. There is contracting and expending in its musscle that allow the movement.

Many snails are herbivorous, eating plants or rasping algae from surface with the radula although a few land species and many marine species are omnivores or predatory carnivores. Apart from being relished as gourmet food, several species of  land snails provides an easily harvested source of protein to many people in poor community around the world. Many land snails are valuable because they can feed on a wide. Range of agricultural wastes such as shed leaves in banana plantations.

In some countries, Giant African land snail, are produced commercially for food. Land snail fresh water snails. Sea snail are all eaten in a number of countries. Principally in a country like Spain Philippines, Morocco, Algeria, France, Cyprus, Belgium, Ghana and Nigeria.

The eggs of certain snail species are eaten in a fashion similar to the way caviar is eaten. During the cold weather snails hibernate in the top soil. During hot dry period or when it is cold, snails seal them selves off with a parachmenlike membrane and often attach themselves to tree trunks, fences or walls. Snail is an invertebrate animal that is with no back bone.

Snails are more active at night, they may come out during the early morning hours as well. The snails are hermaphrodites meaning they have the ability to produce both sperm and eggs when they are mating they will both conceive and lay eggs.

Apart of snail and slugs appearing in cuisine as luxuries they have occasionally been used as famine food in historical times.

In addition to the farming of edible snails they also impact agriculture as a pest. Snails and slugs destroy crops by eating roots, leaves, stems and fruits. They are able to abrade and consume a large variety of plants with the abrasive radula. Due to its slowness, the snail has tradition been seen as a symbol of laziness. In Christian culture, it has been used as a symbol of the deadly sin of sloth fulnem (psalm 58:8) uses snail slime as a metaphorical punishment.

Also, snails are widely noted and used in divination. The Greek poet Hesiod wrote that snails signified the time to harvest by climbing the stalks. While the Aztec moon god Tecciztecati  bore a snail shell on his back. This symbolized rebirth, the snail’s penchant for appearing and disappearing was analogized with the moon.

Professor Ronald Chase of Me Gill University has suggested that the ancient myth of cupids arrows might be based on  early observation of the love dart behaviours of the land snail species.

There are four species of edible land snails according to experts. They are:

Achahana achatina

Archatina marginata

Achatina fulica

Limicolaria

Each of these species has its local name or names.

Achatina marginat: It is bigger than any other species of land snails. Some call it African ‘Giant’ snail of exaggeration while some call it ‘Big Black snail. The shell is multi- color: black brown, dotted white and light yellowish  spots. Otherwise, natural camouflage which hides all land snails from their enemies.

Achatina achatina: Is next in size it has wavy black lines with light yellowish or brownish colour in between. At the right side of the face is red stripe which is white in the achatina marginata. The meat is soft and palatable to international taste. The Achatina achatina has a pointed tip and has more attractive look than all other species of animal.

Achatina fulica: it has a smaller strutted body it is next to achatina achatina in size with white or black feature of flesh in the shell.

Limocolaria: it is also called ‘GARDEN SNAIL’ is so called because, it is commonly found in the garden, clasping plants and twigs. It is the smallest of all eatable snails.

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