Nutrient composition of some local snail feeds and effects of some feed formulae derived there from on the growth of Giant African Snail (Achatina achutina)

Snail farming has become increasingly important in Ghana with the numbers of farmers being increased over the years. Among the major problems being experienced by snail farmers is inappropriate feeding leading to low productivity. It was therefore decided to identify available feedstuffs palatable to the snails, analyse their nutrient composition and evaluate the effects of some feeds that could be used by snail farmers. Snail farming communities in the East Akyem and Fanteakwah Districts- both major snail farming communities were selected for the first part of the study which involved the identification of feeds commonly fed to snails. Structured and semi-structured questionnaires were used during this phase. A total of forty (40) snail feedstuffs including fruits, leaves, stems, flowers, vegetables and agro by-products were identified in eight (8) snail fanning communities. Sweet orange (Citrus sinensis) fruit, wheat (Triticum aestivum) bran, pawpaw (Carica papaya) leaves, avocado pear (Persea americana), sweet potato (Ipomoea batatas) leaves, mango (Mangfera indica) fruit and cassava (Manihot esculenta) tuber were more frequently used by the farmers in the area. Pawpaw fruit and cocoyam (Xanthosoma sagittfolium) leaves especially were recognized by the farmers as very palatable for snails and hence utilized by all the farmers interviewed. However, the leaves of bitter leaf (Vernonia amygdalina), lettuce (Lactuca sativa) and neem (Azadirachta indica) were least preferred and were seldomly utilized by the farmers. Cucumber (Cucumis sativus) fruit, soybean (Glycine max) meal, baobab (Adansonia digitata), cockscomb (Celosia argentea), amaranths (Amaranthus species), jews mallow (Corchorus olitorius) and cabbage (Brassica species) even though are palatable to the snails, are hardly used by the farmers because they are scarce in the study area. Proximate analyses of 27 of the highly preferred feedstuffs indicated a varying nutrient content with crude protein (CP) ranging from 1.64- 42.97%. The root crops generally have the lowest CP content (1.64 and 8.70% for M esculenta and X sagittfo1ium tubers respectively) while the CP was relatively higher in the leaves (18.38 — 24.73%) making them good sources of protein. Fat content of the leaves (1.32 - 5.68%) exceeded the 1% expectation for vegetables. The crude fibre (CF) concentration was between 1.70% for X sagittfo1ium tuber and 12.93% in T aestivum bran, while M esculenta tuber and G. max meal have the highest (81.40%) and the lowest (35.92%) nitrogen free extract (NFE) respectively. Ash concentrations were least in Z mays bran (1.76%), M sapientum (1.45%), M esculenta tuber (3.90%) and C. sinensis pulp (3.70%). Moisture ranged from 7.57% to 92.98% among the feedstuffs with wheat bran having the lowest (7.57%) and the Brasslca species having the highest (92.98%). Three of the identified feedstuffs, namely X sagittfolium leaves, M esculenta leaves and T aestivum bran were fed in six different combinations, described as Ti, T2, T3, T4, T5, T6 (Table 2) to a total of 270 snails with a mean initial weight of 9.50 g at the Snail Village Complex of the Faculty of Agriculture, KNUST, Kumasi. There were 3 replications of each treatment with 15 growing snails in each replicate. The duration of feeding was 70 days and feed and water were provided ad libitum. The completely randomized design was used. The weekly intake of diet T5 was significantly higher (P<0.05) than that of the other diets (T1, T2, T3, T4, T6). The lowest feed intake was obtained in snails fed T3. However, diet T5 at the end of the trial period gave the highest live weight gain of 3 .98g while the snails fed diet T3 gave the poorest growth rate of 0.38 g.

Source: KNUST