Farmer: Snail Rearing (Part 3)

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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. However, just as mushrooms, snails are picked in the wild mostly by women and children.

Guidelines to Feeding

Basal feed – this consists of plant leftovers such as leaves of pawpaw, moringa leucaena, potato greens, waterleaf, cabbage, lettuce, carrot, amaranthus, and pumpkin;  and peelings from pawpaw, pineapple and bananas. Serve the residues ad libitum. The distribution may not be easy, more so with plant leftovers.

Feed prohibitions – some materials are harmful to snails directly or indirectly: a) Salt (Sodium chloride) kills snails; b) Acidic or spicy plants, e.g. lime, eucalyptus, ginger, neem, bitter leaf; c) Orange residue fed to snails attracts red ants.

Feed supplements (12% crude protein) – these consist of 80% bran (wheat, maize, sorghum, rice, and 20% shell (oyster, poultry eggs, snail).

Some feeds are modified for the growers and they include: 85% pig growers + 10% CaCo3 + 5% wheat flour as well as 80% pheasant feed + 10% CaCO3 + 10% wheat flour. Supplements are provided at least 3 times a week. Avoid supplement stored for over 4 months.

Feed distribution – Feeds are served in the night. The first service of feed starts in the evening before snails become active to pick them. Supplements (rations) are served as follow: (a) 1.5g/Breeder/day and (b) 1g/grower/day. Feed can be served at any other times if the conditions are conducive for activity.

Water – this is also served as an essential element to accompany the feeds for metabolism.

Feeding equipment – these are made up of: (a) feeders, the thin flat objects which are used, e.g. flattened iron roofing sheets and (b) drinker, very shallow containers such as plastic plates, which prevent drowning of the snails.

It is important to clean these containers before every service. While carrying out some routine or other activities with snails, care must be taken not to break the edge of the opening of the shell (which is very fragile), as such breakage retards their growth.

Digestion

The feeds, after being eaten, are crushed by the RADULA and soaked in saliva, which does not contain an active digestive enzyme. Only the digestive glands will break down the fat, protein and starch. This gland contains an enzyme called glucuronidase. The intestine contains a flora which is capable of breaking down cellulose.

 Growth and Reproduction

Green feed is more suitable for fattening in open parks. Growth varies with the species, breed, individual snail, climate, season, feeding among other factors.

At birth, snails weigh an average of 1 gram and the shell in its longest diameter measures 20mm. Its growth is faster at the beginning (1 gram/day) if the climate conditions are favorable. In all, acceptable growth varies between 0.7g and 1g/day. This gives a snail growth of 200g to 300g in 10 months of fattening. The growth will be arrested during hibernation and will recommence the following spring. After 12 – 18 months of existence, the shell thickens and the peristome reflected. The snail is then referred to as EDGE. Its growth in size is terminated and cannot but eventually loses weight. In the wild, it takes about 12 to 18 months for a snail to attain its adult size.

The feed conversion ratio (quantity of feed necessary to produce 1kg of snail) is 1.5 to 2.5 averaging 2.0 (for concentrated feed). Garden vegetable contain 85% water, giving a feed conversion of 4.8  to 7.0. The higher the temperature, the lower the feed conversion is (4.8 at 200C). However, progress needs to be made in order to improve the feed supplements. The entire husbandry methodology can still be improved notably in managing better hibernation and reproduction.

Reproduction

After a certain time the edges of the opening of the shell curve outside. The snail is therefore “edged,” a period which indicates that it is an adult and can enter into reproduction. Snails are hermaphrodites, but mating is necessary for cross fertilization to take place. They lay eggs which, on hatching, give young snails similar to the adults in form.

Sexual maturity

For the early maturing species (Achatina fullica), sexual maturity is reached in the wild around the age of 6 months, at which time the shell length is 6 cm. It is late maturing (10 to 12 months) for the giant species measuring 12.5 cm and live weight of 500g, especially for Archachatina margina, and Archachatina achatina.

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