Snail Rearing (Part 1)

0
2737
Snails

By Bisi Klah

Introduction

Farming, fishing and hunting were the major traditional providers of food in Africa. Unlike hunting for other wildlife, the emphasis on snail is lesser, more remote or even absent, just as mushrooms and snails are picked in the wild mostly by women and children.

In some instances, snail is the traditional food for numerous people in Africa and other parts of the world. Snail is a mollusk and at the same time an hermaphrodite. Its husbandry is grouped among the micro-livestock. The rearing is referred to as snail culture. A snailery is a place where snails are reared. For the purpose of difference, the rearing of the genus considered in this guide can be called ACHATINICULTURE.

Giant land snail is a tropical species which originated from southeast Africa and Madagascar that was introduced in the 19th and 20th centuries into many islands of the Indian Ocean, southeast Asia and Oceania (India, Thailand, Taiwan, Philippines). It is an animal of big size which can weigh up to 250g among adults.

In African countries, in spite of many steps and small scale trials in Ivory Coast, Ghana and Nigeria, the snail production business does not seem to exist. However, European research is very advanced and commercial snail production is already working.

Description of the external features

The description of the external features are the shell – this constitutes of apex, suture, peristom, columella, navel, growth lines, and spiral opening; and the body – which constitutes of foot, head (mouth, ocular tentacles, tactile), genital orifice, visceral mass.

The role of snail in community development

The role of snails in community development includes but is not limited to the following: Source of protein – African snail meat contains of between 37 to 50% crude protein (dry matter basis) and has more lysine and Arginine than other creatures of its size, which makes it an interesting food source. It is, however, poor in methionine.

Another role is that it is a source of revenue (employment). It helps also for the diversification of rural production, as well as a source of protein for monogastrics in fish mills or in the bush to satisfy a great part of the protein needs of scavenging poultry and pigs.

The snail has several medicinal values such as pharmaceutical production of the enzyme glucuronidase, which is present in the liver of mammals (cattle) and the digestive glands of snails. It gives regulation of blood pressure (good source of calcium as the treatment of ulcer and wounds, including incurable wounds).

Snail is good in the treatment of anaemia (high in iron content), contains less cholesterol/fat, which leads to most heart diseases, and for easy delivery for women.

Geographical distribution

Edible snails are more often gastropod pulmonary molluscs. That is invertebrate terrestrial animals with pulmonary respiration. The nomenclature can be a bit confused and practically all the species are called giant snails. Some talk of 50 to 80 species, others talk of 8 sub-genuses, while others mention 7 sub-species in Achatina.

The genus Achatina is African and sub-Saharan, with Achatina in West Africa where the following sub-species can be found: An achatina monochromatica (monochrome without dark lines in Liberia, Benin and Sierra Leone); an achatini balteata (very long) in Cameroon and D.R. Congo.

Everything indicates that the species African Achatini fulica Bowdich, have adapted to Asia, Malaysia and most of the pacific islands. Some countries start to consider it as a pest of crop especially of vegetables.

The genus Archachatina would be restricted to forest West and Central Africa, from Sierra Leone to D.R. Congo, with 4 sub-genuses. The three common species belonging to the sub-genus Calachatini are: (1) Archchatina (Calachatina) marginata, Archchatina degneri, and Archchatina ventricosa.

It should be noted that in a flock of snails procured from rural markets, it is possible to have up to 5% carrying the traits of a marginata. The edible African giant snails belong to two genuses differentiated by the shell morphology and the mode of egg production.

Climate and housing

The basic knowledge on the biology, ecology and physiology of tropical snails is still very insufficient. Snails are active when the conditions of humidity and temperature are favorable. During unfavorable periods, snails move into a phase of retarded life.

Some species reduce their activities through hibernation (very hot and dry season); at awakening, the development continues. Hibernation and awakening can be controlled by man.

Mode of life

During its daily activity when the conditions of temperature and humidity are optimal, as from the night fall (dusk), the snail comes out from its shell and becomes active until the break of day (dawn). During humid times, the snail can equally show activity, if the light is less intense.

Its seasonal activity, apart from appropriate periods when it is in active life, snails present a retarded summer mode of life during the period of dryness and heat, at which time it withdraws into its shell (Hibernation).

To do this, it digs a hole in the ground, stays there, with the shell opening placed right up, and withdrawing entirely into its shell. Afterwards, it secretes a mucous film, which hardens and turns white (chalky epiphramgm), also called Opercule. During hibernation all the metabolism are retarded. It lives on its reserves (it emaciates) at spring, and recovers quickly the lost reserves.

Leave a Reply