African Land Snail Research Articles

The secondary invasion of giant African land snail has little impact on litter or seedling dynamics in rainforest

AbstractIn the absence of empirical evidence, invasive species are often assumed to have negative impacts because of their conspicuously high abundance. The giant African land snail Achatina (Lissachatina) fulica is one such invader where its impact in natural ecosystems remains completely untested. On Christmas Island (Indian Ocean), A. fulica has become established across large tracts of rainforest following the impacts of invasive yellow crazy ant (Anoplolepis gracilipes) in mutualism with non‐native scale insects. Yellow crazy ants facilitate the secondary invasion of A. fulica by extirpating native red land crabs (Gecarcoidea natalis) that are normally effective predators of A. fulica. We used a multifaceted approach to investigate some potential impacts of abundant A. fulica in invaded rainforest. Over the course of a wet season, diel activity transects showed that A. fulica consumed detrital material almost exclusively. However, stable isotope analysis did not confidently identify A. fulica as a predominantly detritivorous species. We found no statistically significant treatment effects of A. fulica exclusion on standing leaf litter and seedling recruitment processes during a 6‐month manipulative field study. However, litter cover and biomass did remain slightly higher where A. fulica were excluded, albeit with overlapping confidence intervals with control plots. Our study constitutes the first empirical test for impact of A. fulica in a natural ecosystem and suggests that for Christmas Island rainforest, this species is not a damaging invader. Other studies will need to assess the impacts of A. fulica in other natural areas before these findings could be considered broadly applicable.

The effects of different heating periods and exclusion of some fermentation conditions on bioethanol production from plantain pseudo-stem waste using the digestive juice of Archachatina marginata, garlic and Saccharomyces cerevisiae

ABSTRACTLignocellulosic biomass represents the largest renewable reservoir of potentially fermentable carbohydrates on earth, and its utilization for ethanol production continues to be a subject of worldwide interest. The present study evaluated the effect of 0, 30, 60 and 90 min heating periods on fermentation setups containing a mixture of 100 g plantain pseudo-stem waste, 250 ml of digestive juice of African land snail (Archachatina marginata), 4 g garlic and 200 ml of yeast slurry. On exclusion of some fermentation conditions, the yield of ethanol was evaluated for fermentation setups excluding yeast and garlic, yeast only, digestive juice of African land snail and garlic, digestive juice of African land snail only, and garlic. From the results, the best yield of ethanol at 76.0 ml ± 3.5 of distillate containing 21.7% ± 2.1 (w/v) ethanol composition was obtained at 60 min heating period, which declined continuously as the heating period increased to 90 min. No significant change (p ) in the ethanol yield was observed between the fermentation setups excluding the digestive juice of snail and garlic, and yeast only. The ethanol yield obtained from the fermentation setup excluding garlic alone was 79.7 ml ± 2.5 distillate containing 9.7% ± 1.5 ethanol by volume and the formation of acetic acid. This result suggests that the optimum heating period to enable the accessibility of cellulose degrading enzymes from the digestive juice of the African land snail is 60 min, and that constituents of garlic can promote the inhibition of acetic acid synthesis from fermentation.

Modelo alimenticio y actividad de los enzimas digestivos del Caracol Africano Gigante (Archachatina marginata) durante las fases de crecimiento

Los caracoles comen diferentes clases de alimentos presentes en su hábitat. En este trabajo, se analizan el modelo de alimentación, la presencia de microbios en el tracto digestivo y las actividades de los enzimas digestivos (proteinasa, lipasa, celulasa, glucosidasa y α-glucosidasa) del Caracol Africano Gigante (Archachatina marginata) en tres etapas de crecimiento. Los resultados ponen de manifiesto que que los caracoles en todas las fases de crecimiento, se alimentan durante el periodo nocturno (19:00 a 4:00 GMT), por otro lado, los caracoles en la fase juvenil dedican más tiempo a la alimentación e ingieren mayor cantidad de alimento que en las otras dos fases de crecimiento. Las actividades de los enzimas digestivos fueron afectadas significativamente por la fase de crecimiento, siendo en la fase adulta cuando se registra la máxima actividad de todos los enzimas estudiados, seguida por la fase juvenil, registrándose la actividad mínima en la etapa inicial. La región estomacal es la parte del tracto digestivo con mayor actividad enzimática, registrándose los valores mínimos en el esófago. Se identificó la presencia de muchas especies microbianas en el tubo digestivo a lo largo de las etapas de crecimiento, siendo mayor la presencia de bacterias que la de hongos. Estos hallazgos sugieren que A.marginata en la fase adulta, está mejor equipada para hidrolizar sus numerosas dietas.

Nutritional Composition of African Giant Land Snail (Archachatina marginata) Fed on Diet from Different Protein Sources

Nutritional Composition of African Giant Land Snail (Archachatina marginata) Fed on Diet from Different Protein Sources

Phenotypic Correlations and Body Weight Prediction of Two Ectotypes of Giant African Land Snails (Archachatina maginata, Swain.) Based on Number of Whorls in Calabar, Nigeria

Phenotypic Correlations and Body Weight Prediction of Two Ectotypes of Giant African Land Snails (Archachatina maginata, Swain.) Based on Number of Whorls in Calabar, Nigeria

Localization of oestrogen hormone receptors in the reproductive tract of giant African land snail (Archachatina marginata) and potential role of Mucuna pruriens on level of expression

This study determines localization of oestrogen hormone receptors in selected parts of the reproductive tract of giant African land snail (Archachatina marginata) and potential role of Mucuna pruriens on levels of expression. Thirty (30) snails were used for this experiment, with average weight of 100-150g. The snails were allotted to three dietary treatments which includes concentrate (CON), concentrate + Mucuna pruriens (CON+MSP) and Mucuna pruriens seed powder only (MSP). Each treatment contains 10 Replicate each. After eight weeks, five snails were randomly selected from each dietary treatment and dissected. Organs removed were oviduct, albumen gland, ovo-testis and the spermatheca. RNA and DNA extractions were carried out with commercial kits. Gel electrophoresis on 1% agarose was also carried out to evaluate the expression. Primers sequence used were the forward and reverse β oestrogen primer which was designed to detect the expression of the gene encoding oestrogen receptor in the reproductive tract of the giant African Land Snail (Archachatina marginata) were: Forward: 5’-GCT TCG AGC TCA GCC TG-3’ Reverse: 5’-AGG ATC ATG GCC TTG ACA CAG A-3’. Result showed that receptors for estrogen were present in oviduct, albumen gland, ovo-testis and spermatheca for both RNA and DNA analysis considering CON and MSP. While oviduct was also moderately expressed for CON and MSP. But combination of concentrate and Mucuna seed powder (CON+MSP) showed no visible expression for estrogen receptor. It was however concluded that combination of concentrate and mucuna seed powder (CON+MSP) down-regulate expression of estrogen receptor gene expression. It was recommended that feed to be combined for snail production must be free from substance(s) that has the potential to block the expression of reproductive hormone function.

Yield Response of Biodiesel Production from Heterogeneous and Homogeneous Catalysis of Milk Bush Seed (Thevetia peruviana) Oil

ABSTRACTConventional production of biodiesel employs the use of alkaline catalysts because they are cheaper and less corrosive, and they use minimal energy when compared to other acidic catalysts. Heterogeneous catalysts have also shown significant effects on biodiesel production with its ease of recovery and reusability. Three reaction variables—temperature, time, and molar ratio of alcohol to oil—were optimized for biodiesel production from milk bush oil using snail shell as a catalyst. The catalyst was prepared by calcinating waste giant African land snail in an electric oven for 3.5 hours at 900°C. Also, a control transesterification experiment was carried out using potassium hydroxide (KOH) as a catalyst. Catalyst concentrations of 3.0 wt % of calcined snail shell (CSS) and KOH were used for the transesterification of the oil. A response surface analysis of biodiesel production using CSS as a catalyst showed that all reaction variables were significant. Biodiesel yield of 81% was recorded experimenta...

Genetic differentiation between black-skinned and white-skinned ectotypes of giant African land snails (<i>Archachatina marginata</i>) in Calabar, Nigeria

This noble research provides information on the genetic differentiation between black-skinned and white-skinned ectotypes of giant African land snails (Archachatina marginata). Ten (10) snails consisting of five (5) black-skinned and five (5) white-skinned ectotypes were examined by using the random amplified polymorphic DNA (RAPD) technique. Five (5) primers (OPAD-09, OPAE-04, OPAE-05, OPAF-07 and OPAF-09) were screened and selected to amplify DNA from the ten (10) samples of snails. A total of 31 bands were generated from the two snail types, out of which 14 bands were generated from the black-skinned ectotype, while 17 bands were from the whiteskinned ectotype. The DNA banding between the two ectotypes showed no statistical difference (P > 0.05) between the black-skinned and the white-skinned ectotypes of Archachatina marginata. There were however, relative high genetic differences in numerical number of bands between the two ectotypes. This implied that the genetic similarities are relatively low. The high genetic differences between the two ectotypes of Archachatina marginata snails studied signaled high level of genetic diversity and heterogeneity among the giant African land snails (GALS).Keywords: DNA, Banding, Differentiation, Black-skinned, White-skinned

Impact of changes in fermentation time, volume of yeast, and mass of plantain pseudo-stem substrate on the simultaneous saccharification and fermentation potentials of African land snail digestive juice and yeast.

This study was carried out to investigate the effect of variations in mass of plantain pseudo-stem waste, volume of yeast used, and fermentation time on the product yield resulting from simultaneous saccharification and fermentation using digestive juice of African land snail and yeast. The experiment was divided into three stages which included a total of fifty seven (57) experimental setups containing sixteen (19) different combinations of the varied substrates. The results show that by varying the mass of plantain pseudo-stem waste, the production of ethanol was optimized at a mass of 250 g, which yielded 125.6 ml ± 3.5 of distillate and a percentage ethanol composition of 25.0 ± 3.6. While varying the volume of yeast used between 50 and 250 ml, with 250 g of plantain pseudo-stem waste, 250 ml of snail digestive juice and 4 g garlic for 24 h, acetic acid was detected in the setup containing 200 ml of yeast, but was not detected in similar experimental setups containing 6 g garlic. The optimum ethanol production while varying the volume of yeast slurry was recorded to be 182.3 ml ± 4.9 of distillate with 28.0% ± 1.0 ethanol composition. Variations in fermentation periods had the greatest impact on the percentage composition of ethanol and the volume of ethanol produced showing the best fermentation period for obtaining optimal ethanol production to be at 96 h. These findings show that the best specifications for the optimum production of ethanol from a 250 g of plantain pseudo-stem waste using 250 ml snail digestive, are 200 ml of yeast slurry, 6 g of garlic to ferment for a period of 96 h.

English

In the Greater Accra Region there is high demand in consumption of molluscs, which indicates the need for studies on the possibility of disease transmission. Snail meat is usually susceptible to microbial contamination. Shelling is difficult with possibilities of cross contamination. Slime on the meat becomes a hurdle during commercial processing. The objective of the study was to establish the differences in the microbial load of African land snails (Achatina achatina and Archachatina marginata) from two sources (market and breeding farm) and to enumerate some consumer concerns about the snail meat. The results found that the total viable count (log10 CFU/g) ranged from 6.61±1.25 to 8.29±1.02. The total of coliform count (log10 CFU/g) ranged from 8.50±0.57 to 5.61±1.51. Salmonella count (log10 CFU/g) ranged from 2.91±3.19 to 7.39±0.45. Staphylococcus, Bacillus and Pseudomonas counts (log10 CFU/g) ranged from 7.68±1.40 to 2.66±2.99; 4.90±1.07 to 1.53±1.68 and 5.66±0.14 to 3.97±0.74, respectively. Most microorganisms identified were from the Enterobateriaceae family. Shelling, slime removal, contamination, price, packaging were problems associated with snail meat. Key words: Molluscs, consumer behaviour, Enterobacteriaceae, contamination, food safety, Accra Metropolitan Area, Ghana.

Evaluation of the Phenotypic Characters in Archachatina marginata Hatchlings Fed Leaves of Phyllanthus amarus (Schonn. and Thonn.)

A breeding investigation was carried out to evaluate the effect of Phyllanthus amarus (Schonn. and Thonn.) on the phenotypic characters of hatchlings of Giant African Land Snails (GALS), Achachatina marginata. The phenotypic traits of one hundred (100) hatchlings investigated were live (body) weight (BW), shell mouth length (SML), shell mouth width (SMW), shell length (SL), shell width (SW) and Feed Intake (FI). The snails were randomly assigned to treatment groups A(10%), B(20%), C (30%) inclusion of Phyllanthus amarus powdered leaves into the normal chow of the hatchlings and D (control), with twenty-five (25) snails in each group. 5 weeks after commencement of treatment, the live (body) weights (BW) and shell length (SL) of the snails showed significant differences (p 0.05) The feed intake was highly significant (p<0.01) in all the groups. From the results obtained, P. amarus leaf meal was well tolerated by the hatchlings and is recommended to snail breeders, as a feed supplement for A. marginata hatchlings bred for commercial purposes.

Differentiation in Growth of Body Components Between Two Ectotypes of Giant African Land Snails (Archachatina marginata S.) Based on Number of Whorls in Calabar, Nigeria

Differentiation in Growth of Body Components Between Two Ectotypes of Giant African Land Snails (Archachatina marginata S.) Based on Number of Whorls in Calabar, Nigeria

Performance, nutrient digestibility, carcass analysis and organoleptic assessment of snailets of African giant land snail (Archachatina marginata) fed diets containing graded levels of dried lettuce

There is paucity of information on quality and cheap feedstuffs for snail production in the Tropics. The performance, nutrient digestibility, carcass analysis and organoleptic qualities of snailets of Archachatina marginata fed diets containing graded levels of dried lettuce (DL) were assessed in a 20 week trial. 180 snailets with average weight of 9.18±2.67g were allotted to 4 diets of 45 snailets per treatment and each treatment replicated thrice with 15 snails per replicate. Snailets were randomly distributed into 4 dietary treatments consisting of 0% DL(T1), 25%DL(T2), 50%DL(T3) and 100%DL(T4) with DL replacing maize in a completely randomized design. Water and feed were presented ad libitum while feed intake and weight gain were measured on daily and weekly basis respectively. Shell length and width were measured with vernier caliper while shell thickness was measured with a micrometer screw gauge on weekly basis. The body weight gain, feed per gain and nutrient digestibility of snailets on T1, T2 and T3 were similar, higher and significantly different (P<0.05) from those of snailets on T4. The dressing percentages in all the treatments were similar. The organoleptic assessment revealed that the dietary treatments had no significant effect (P>0.05) on the color, taste, flavor, texture and overall acceptability of the snail meat. Snailets on diet T3 were the best in terms of economy of production by having a feed cost savings of 9.16% when compared with the control diet with no dried lettuce. In conclusion, it can be stated that diet T3 containing 50% DL replacement for maize was the best in terms of performance, nutrient digestibility and economy of production amongst the tested diets.

Prestonellinae-validation of the name as a new subfamily of Bothriembryontidae (Mollusca, Gastropoda, Orthalicoidea).

The affinities of the enigmatic South African land snail genus Prestonella Connolly, 1929 were discussed by Herbert (2007) and Herbert & Mitchell (2009), who showed, on the basis of morphological and molecular data, that the genus is referable to the superfamily Orthalicoidea. Currently, the three described species of Prestonella are the only known African representatives of this diverse superfamily. Earlier, van Bruggen (1978) had recognized that these species formed a distinct group and had placed them in the (new) family Prestonellidae. However, as noted by Bouchet & Rocroi (2005: 140), no diagnosis was provided by van Bruggen; the name Prestonellidae thus does not meet the requirements of ICZN Art. 13.1, and is not an available name. In this paper we will redress this issue, also taking into account more recent research which has shed light on the systematic position of this genus within the Orthalicoidea.

Trace Metals Levels in African Giant Land Snails (Achatina achatina) from Selected Local Government Areas in Akwa Ibom State, Nigeria

Trace metals (As, Cd, Cr, Hg, Pb and Se) in African giant land snails from selected Local Government Areas (LGA) in Akwa Ibom State of Nigeria were analysed using atomic absorption spectrophotometric (AAS) technique. Results showed that the mean levels of Cr (399 ± 195 mg/kg) and Se (51.6 ± 31.3 mg/kg) were significantly higher (P Se > Pb > Cd > As > Hg. The results showed that As and Hg fell within their permissible safe levels; but Cd, Cr, Pb and Se were significantly above safe levels for human consumption. The high concentration of trace metals in the snail samples may be related to anthropogenic activities taking place in the areas studied.

Levels of Some Heavy Metals in African Giant Land Snail (&lt;i&gt;Archachatina marginata&lt;/i&gt;) in Major Markets in Abeokuta, South West Nigeria

The level of heavy metals (Pb, Cu, Cd) as bio indicator of metal pollution in Abeokuta by analysing snails samples from major markets in Abeokuta. The level of heavy metals (Pb, Cu, Cd) were determined using Atomic absorption Spectrophotometer. Analysis of the results showed that the concentration of lead ranged from 4.15 mg/kg in Omida market to 7.93mg/kg in Lafenwa market. Similarly, Copper concentration ranged from 0.339mg/kg in Omida market to 0.719 mg/kg in Lafenwa market. The highest concentration of Cadmium was at Lafenwa market with a value of 0.06 mg/kg. Lafenwa market showed the highest concentration of the three metals and the trend of metal concentration was of the order Pb > Cu > Cd. The levels of contamination of the snail samples were lower than the recommended FAO/WHO levels. However, there is need for regular periodic checking of heavy metals level of edible snails available in open market to safe guard the health of the general public.

A Survey of the Land Snails of Kosrae (Caroline Islands, Micronesia) Including the Rediscovery of EndemicDelos oualanensis(Pease, 1866) (Mollusca: Pulmonata: Rhytididae)

ABSTRACT This is the first published documentation of the land snails from Kosrae Island (eastern Caroline Islands, Micronesia; ∼ 5.3°N, 163°E). Timed hand collecting in leaf litter and emergent vegetation over the course of five days yielded 15 species in 13 gastropod families, including important collections of Delos oualanensis (Rhytididae) and Sinployea kusaieana (Charopidae), which had not been collected since the last survey of Kosrae in the 1930s. We did not recover evidence for in situ diversification in Kosrae — rather, the fauna seems to be a subset of the general Micronesian fauna (especially that of Pohnpei), with endemic species most likely having sister species off-island. An exotic veronicellid slug, and several snails that are widespread and possibly introduced were found, but no giant African land snails (Achatina fulica) were found. Due to its position as the eastern-most high island in Micronesia, Kosrae is an important part of our understanding of both the pre-anthropogenic assembly of...

Partial Purification and Characterization of Cellulase from the Haemolymph of the African Giant Land Snail (Archachatina marginata)

The aim of this study is to partially purify and characterize the cellulase extracted from the snail haemolymph of the African giant land snail of the species, Archachatina marginata. The protein concentration of the haemolymph was found to be 168 mg mLG1 and the specific activity of the crude cellulase was found to be 0.007 U mgG1 protein using Carboxymethyl-cellulose (CMC) as the substrate. The partial purification on Sephadex G-200 produced two activity peaks. The molecular weights of the two cellulase fractions were estimated to be 112,202 and 67,000. The Michealis Menten constant (km) for cellulase was 4.3 and 2.8 mg mLG1 for the higher and lower molecular weight fractions, respectively. The multiplicity of cellulase complexes indicated that the haemolymph of A. marginata may convert derived cellulose in foodstuffs such as garlic, mushrooms and domestic wastes into sources of fuel. It is suggested that the enzyme can be used to produce value-added products, such as ethanol, citric acid, amino acids and vitamins including primary metabolites from cellulosic wastes.

Effect of feed on the growth rate of African giant land snail, &lt;i&gt;Archachatina marginata&lt;/i&gt; Swainson

The effects of three feed combinations on the growth rate of the African Giant snail, Archachatina marginata , were investigated at the snailery unit of Forestry and Wildlife Department of University of Uyo, Akwa Ibom State, Nigeria. Growth parameters measured included; changes in snail weight, shell length and shell height. The experiment consisted of three treatments replicated thrice with ten snails in each replicate. The experiment was laid out using the Complete Randomize Design (CRD). Result shows that Treatment A had the highest bi-monthly mean values of 2.47g for weight, 0.15cm for shell length and 0.13cm for shell height; followed by treatment B with 1.79g, 0.12cm and 0.10cm for weight, shell length and shell height respectively. Treatment C (control) had the least bi-monthly mean values for weight (1.50g), shell length (0.11cm) and shell height (0.07cm). Significant differences (p<0.05) were recorded for all the treatments for gain in weight, shell length and shell height. Therefore, it was concluded that feed combination of treatment A was well balanced in terms of dietary energy and protein densities resulting from its high acceptability to the animals which is responsible for the optimum performance indices recorded. It is recommended that the rearing of snails should be practiced in small farms where these crops are grown. Pawpaw fruit should be used as a part of feed combinations served snails; efforts should be made to ensure that soils rich in nutrients are used for snail rearing. Keywords : growth rate, feed combination, height, length, snail, weight

Effect of post-gut loading time on the macro-nutrient content of three feeder invertebrate species

Techniques for increasing the nutritional value of feeder invertebrates include dusting the prey items with a vitamin and mineral powder supplement, or providing the invertebrates with nutrient-rich food, called gut loading, prior to feeding to insectivores. However, the delay between gut loading of prey and consumption by insectivores varies according to feeding regime and may be considerable if prey is left in the vivarium. This study aimed to determine the effect of time post gut loading on the nutritional composition of three species of invertebrates, mealworms ( Tenebrio molitor larvae, approximately 23–30 mm), giant African land snails ( Achatina fulica , shell size 10–35 mm) and dubia cockroaches ( Blaptica dubia , approximately 20–30 mm). Feeder invertebrates were maintained on a dry commercial gut-loading diet, supplemented with fresh vegetables for 48 hours, after which the diet was removed. Samples of invertebrates (120 g of mealworms, 80 g of snails and 100 g of cockroaches) were taken for proximate analysis (dry matter, ash, crude fat and crude protein) at 0.5 h (excluding cockroaches), 1 h, 6 h and 12 h (excluding snails) using standard laboratory procedures. A one-way analysis of variance was performed to test for differences in nutrient content between time points in each species. Crude protein and fat contents of snails were significantly greater at 6 h compared to 0 h (P < 0.01). However, no other significant differences in nutrient content of snails or other species were detected at any time points. It is feasible that the increases in crude protein and fat of snails were a result of nutrient accumulation within the body. These findings indicate that in the species tested, with the exception of snails, delays of up to 12 hours between gut loading of the prey and their consumption by a carnivore are unlikely to affect the concentrations of macro-nutrients (protein, fat, dry matter and ash).