Snail meat has been consumed by humans throughout the world since prehistoric times. It is high protein (12-16%) and irons (45-50mg/kg), low in fat (0.05-0.8%) and contains almost all the amino acids needed by humans. In addition to the nutritional value of snail meat, a recent study has shown that the glandular substances from edible snails cause agglutination of certain bacteria; this could be of value against a variety of ailments, including whooping cough. In Nigeria, Ghana and Cote d’ivoire, where snail meat is particularly popular, snails are gathered from the forest during the wet season. In recent years, however, wild snail populations have declined considerably, primarily because of the impact of such human activities as deforestation, pesticide use, slash-and-burn agriculture, spontaneous burn fires, and the collection of snails before they have reached maturity. It is therefore important to encourage snail farming (heliculture) as a means of conserving these important resources. Snails are slow growing animals and as such do not represent a way of making money quickly. With patience, good management and careful integration into existing farming activities, however, snail farming will bring substantial rewards in the longer term.
2.0 SELECTING SUITABLE SPECIES AND CHOOSING A SITE
Snails belong to a group of invertebrate animals known as MOLLUSCA. The snail is a hermaphrodite. It has both the male and female sexual organs so one cannot really distinguish between the male and female specie of it. 2.1 BIOLOGY OF SNAILS
Essentially, a snail consists of two parts; the body and the shell. The body is divided into three parts-the head, the foot, and visceral mass. The head is not well demarcated and carries two pairs of retractable tentacles. One pair is far longer than the other and contains the eyes in the knobbed end. The long muscular foot occupies almost all the ventral surface and like the head, is not clearly demarcated from the rest of the body. There is a shallow longitudinal groove along the centre of the foot. The visceral mass is housed in the shell above the foot. It is humped-shaped and contains the digestive, reproductive and respiratory organs. The skin over the visceral hump secrets a large calcareous shell (98% of the shell is in the form of calcium carbonate). In most species, the shell accounts for about a third of the body weight. It is the snail’s protective casing. When danger threatens, the snail withdraws its body into the shell.
Although snails are hermaphrodites, the individuals will mate with each other before laying eggs. However, the African giant Achatina achatina reproduces by self- fertilization. Unlike many species, reproduction is not preceded by coupling, although it is not unusual to find two snails in close proximity. Laying usually takes place in the late evening and night. On warm humid days, however, egg- laying may occur during the day.Eggs are deposited in dug-out holes about 4cm deep. Usually, the eggs hatch 2-3weeks after laying. The baby snail possesses a thin shell membrane which calcifies progressively. Although this period is characterized by rapid growth, the snails are able to survive the first few days without food. This is perhaps an evolutionary adaptation for an organism with poor mobility. The juvenile phase covers the period between 1 and 2 months to the stage of sexual maturity (14-20months). At the end of this period, the shell is well formed and the snail weighs between 100g and 450g. The adult phase starts when the snail reaches sexual maturity. An average life expectancy of a snail is 5-6 years, although there are reports of snails surviving up to 5 or 10 years. 2.2 RECOMMENDED SPECIES FOR SNAIL FARMING
A list of some edible snail species of both African and European origin is provided below: The most popular edible snails in West Africa are the giant snail, Achatina achatina and the big black,...