Eco-physiological adaptation of the land snail Achatina achatina (Gastropoda: Pulmonata) in tropical agro-ecosystem (original) (raw)
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The survival of land snails in an adverse environmental condition depends on the integral physiological, morphological and behavioural adaptations. These adaptations are essential in understanding the species-specific habitat requirements and in predicting their environmental responses. In this study, the monthly and the periodic patterns of eco-physiological adaptation of land snail, Achatina achatina in Nsukka tropical agro-ecosystem were assessed from December 2012 to July 2013. Standard methods were employed in sampling the land snail and determination of the water content, biochemical fuel reserves and enzyme concentrations of the samples. The present results showed that lipids were high at the beginning of aestivation and depleted as the aestiva-tion progressed. Glycogen was significantly low throughout the aestivation months (December– March) and increased in the active months (April–July). Protein content recorded a definite pattern all through the months studied. Catabolism of lactate and a decrease in activity of LDH during aestivation and substantial increase upon activation were observed. Data showed that transaminase and aspartate enzymes depleted during the aestivation months indicating that the snails may have developed potential cell injury due to oxidative stress and thermal heat. A disassociation between the physiological responses and climatic data was recorded. The physiological adaptation of A. achatina ensures regular adjustment under extreme conditions and compensates for its metabolic regulation in the tropics. It is concluded that survival of A. achatina is not environmentally
Comparative Biochemistry and Physiology Part A: Molecular & Integrative Physiology, 2017
Land snails species occur in a range of habitats from humid to semi-arid and arid ones and seasonal variations in their physiology and biochemical composition have been linked to annual cycles of photoperiod, temperature, humidity and water availability. In an effort to understand the thermal tolerance and the impact of temperature elevation on tissue metabolism of land snails we determined the mortality, heamolymph PO 2 and the activities of enzymes of intermediary metabolism in three land snail species (Helix lucorum, Helix pomatia and Cornu aspersum) differing in their geographical distribution and inhabiting areas with different climatic characteristics. No mortality was observed in both population of Cornu aspersum, while Helix pomatia exhibited higher mortality than Helix lucorum. PO 2 dropped within the first 10 days of exposure to elevated temperature in all species, although in Cornu aspersum this decrease was significantly lower. No significant reduction in the enzymatic activities of all glycolytic enzymes studied, as well as of citrate synthase (CS) and 3-hydroxyacyl-CoA dehydrogenase (HOAD) was observed in the more thermal tolerant species C. aspersum from both populations studied. Significant reductions of enzymatic activity of the glycolytic enzymes phosphofructokinase (PFK), pyruvate kinase (PK) and D-Lactate dehydrogenase (D-LDH) was observed in Helix lucorum and Helix pomatia. The observed inter-specific differences seem to be in accordance with the life cycle characteristics of each species and may be attributed to climatic differences among habitats within their distribution range.
Asian Science Bulletin, 2024
Background and Objective: Prevailing climatic conditions of a given region affect the physiological and biochemical adjustment in snails. Numerous researches have been published on physiological parameters of commonly eaten Achatina achatina from different ecological zones in Northcentral and Western Nigeria. There is a paucity of updated information on the physiological indices of giant African land snails in Niger Delta regions of Nigeria. This research was aimed at evaluating the physiological indices of a commonly eaten giant African land snail (Achatina achatina) from 5 different ecological zones in Niger Delta regions of Nigeria. Materials and Methods: The 25 matured snails were purchased from farmers returning from the forests in Akwa Ibom, Abia, Bayelsa, Rivers and Cross River States, respectively for this study. The snails were transferred to the biochemistry laboratory for physiological analyses. Data obtained were subjected to analysis of variance using SPSS version 16.0 and least significant difference test was used to separate the means. Significance level was set at 5%. Results: Snails from Rivers State had higher significant (p<0.05) concentrations of protein (52.13±0.03), glucose (33.01±0.20) and lipid (20.80±0.04), respectively in their hemolymph than those recorded for other locations. The concentration of protein was higher than other metabolites in both hemolymph and the flesh of Achatina achatina across the 5 States. Achatina achatina snails obtained from Akwa Ibom state recorded higher and significant (p<0.05) values of dry matter (24.05±0.03), ash (1.84±0.02), crude fibre (1.02±0.01), fat (2.02±0.01), carbohydrate (1.09±0.02) and crude protein (22.20±0.04), respectively than those from other States of Niger Delta Region in Nigeria. No significant (p>0.05) difference was observed in Mg 2+ , PO 4 2+ and ClG across the 5 states. Conclusion: Locations that have effects on chemical composition of the hemolymph have been observed, but no substantial differences were recorded in the nutritional composition of Achatina achatina snails across the 5 Niger Delta States in Nigeria.
Journal of Molluscan Studies, 2005
We examined the seasonal patterns of physiology and biochemical composition in the rock-dwelling clausiliid land snail Albinaria caerulea in relation to its ecology, morphology and climatic data. We found that A. caerulea displayed significant seasonal changes in biochemical composition and enzyme activity, especially during aestivation. Sugars were catabolized early in aestivation, and proteins and lipids seem to be the primary metabolic substrates after sugar reserves were depleted. Atypical for aestivating land snails was the accumulation of lactate and LDH during the first weeks of aestivation, possibly suggesting that anaerobic pathways can provide additional energy. Moreover, mortality was not significantly higher during aestivation, fresh-mass differences between the aestivation and active period were not substantial and the rate of fresh-mass decline during aestivation was low. In addition, A. caerulea shows a series of morphological (thick white shell, strengthened and reflected apertural lips, thick epiphragm, internal lamellae, door-like clausilium) and behavioural (high aggregation) characteristics that support survival during adverse climatic conditions by preventing desiccation. We did not find a correlation of biochemical variables (except LDH) with climatic conditions. Yet, the biochemical variables, taken as a whole, are sufficient to distinguish the periods of aestivation and activity. The above suggest that the start of aestivation is primarily controlled by an endogenous component, and perhaps changes in the biochemical composition are a by-product of this component and not a direct response to climatic conditions. These results, in conjunction with the non-elevated mortality during aestivation, indicate that in this Albinaria population morphological, behavioural and physiological adaptations to the dry conditions of the climatically unpredictable Mediterranean-type ecosystems are in effect, and seem to ensure sufficient water and fuel reserves.
Archives of Applied Science Research, 2010
The role of biochemical activities in the mechanisms that might control the transition of the giant African land snails, A. marginata and A. achatina, from aestivation to arousal were investigated in the study. Twenty snails each of the species were divided into four groups each. The experiment was conducted in a completely randomized design laid out in a species x week factorial arrangement. All groups were aestivated for 6 weeks. The control group was slaughtered at the end of the aestivation period, whereas the other groups were moistened and fed. These were slaughtered 2, 4 and 6 weeks after arousal. The results showed that no significant species differences (P > 0.05) were observed in chemical composition during postaestivation. The crude protein significantly (P < 0.05) increases over the first 4 weeks and then recovered slowly towards the control values. The increase and recovery of crude protein reflect the rate of upgrading of protein synthesis and an increase in the ...
Land snails usually exhibit cycles of activity and dormancy (aestivation or hibernation). The transition between these two states is accompanied by a range of behavioural and physiological responses to ensure their survival under adverse environmental conditions. Furthermore, aestivation plays an important role in shaping species' distribution patterns. We examined the seasonal patterns in biochemical tissue composition in relation to aspects of behavioural ecology in three land snail populations: one mainland and one insular population of the widespread Helix aspersa and a population (sympatric with the latter) of Helix figulina, a congeneric species with a narrow and declining distribution. Helix figulina aestivates in underground borrows, while H. aspersa spends the summer under stones and may interrupt aestivation when conditions become favourable. Prior to aestivation H. figulina accumulates metabolic fuels, which it consumes later during summer, and at the same time loses substantial body water and increases lactate dehydrogenase (LDH) activity. The insular H. aspersa population follows a similar pattern (regarding metabolites and LDH activity), with the difference that water loss is limited. However, the mainland population of H. aspersa deviates from this model with energy metabolites and water levels showing little variation throughout the year, while LDH activity is reduced. These differences probably reflect the particular behavioural and physiological patterns adopted by each species. The specialist and range-restricted H. figulina shows a constant and more predictable seasonal pattern, which may be effective for surviving in its historical biogeographic range, but it seems to be more vulnerable to possibly changing environmental conditions. On the other hand the generalist and cosmopolitan H. aspersa adopts a more flexible pattern that compensates for the effects of adverse conditions during aestivation and permits a more effective exploitation of energy resources.
Journal of Experimental Biology, 2021
Temperature, a major abiotic environmental factor, regulates various physiological functions in land snails and therefore determines their biogeographical distribution. Thus, species with different distributions may present different thermal tolerance limits. Additionally, the intense reactivation of snail metabolic rate upon arousal from hibernation or estivation may provoke stress. Land snails, Helix lucorum, display a wide altitudinal distribution resulting in populations being exposed to different seasonal temperature variations. The aim of the present study was to investigate the expression of heat shock proteins (Hsps), mitogen activated protein kinases (MAPKs) and proteins that are related to apoptosis (Bcl-2, ubiquitin), that have ‘cytoprotective’ roles and are also considered to be reliable indicators of stress because of their crucial role in maintaining cellular homeostasis. These proteins were assessed in H. lucorum individuals from two different populations, one at Axio...
African Journal of Food, Agriculture, Nutrition and Development, 2011
Nutritional and organoleptic properties of the African giant land snails (Archachatina marginata) were investigated using 96 healthy-looking growing snails maintained on broiler starter mash (BSM) as control, Talinium triangulare or waterleaf, Centrosema molle or centro leaves, and Carica papaya or pawpaw leaves for 16 weeks. This study was set up as a completely randomized design (CRD) with the snails allocated to 4 treatment groups (broiler starter mash (BSM) as control; Talinium triangulare leaves or waterleaf; Centrosema molle or centro leaves; Carica papaya or pawpaw leaves) and 3 replications each of 8 snails (giving a total of 24 snails per treatment group). At the end of the 16-week period, 4 snails were each harvested at random from the 3 replicates of each of the 4 treatments, sacrificed, processed and analyzed. Dry matter (DM), ash, fat or ether extract (EE) and nitrogen-free extract (NFE) were higher (P < 0.05) in the BSM group, while crude fibre (CF) was higher (P < 0.05) in centro leaves (34.2 g/100 g) and crude protein (CP) was higher in pawpaw leaves. Meancholesterol level was very low (0.003 ± 0.0006 mg/100 g) in the snail. Negative correlation (r =-0.99; P < 0.05) was recorded between diet CF and moisture content of the snail meat, while feed EE had a positive correlation (r = 0.98; P < 0.05) with snail cholesterol level. Based on tastiness, toughness and tenderness of the snails fried and stewed with spices or only steamed without spices, preference ranking in descending order gave pawpaw leaves > BSM = centro leaves > waterleaf. Thus, snails fed pawpaw leaves performed better than the control diet and could be exploited as a cheap feed resource for smallholder snail production in the humid tropics. Low fat and cholesterol levels in the African giant land snail make it very suitable for ameliorating human cardiovascular-related diseases.
Journal of Comparative Physiology B-biochemical Systemic and Environmental Physiology, 2013
The pulmonate snail Chondrina avenacea lives on exposed rock walls where it experiences drastic daily and seasonal fluctuations of abiotic conditions and food availability. We found that tolerance to dry conditions was maintained at a very high level throughout the year and was mainly based on the snails' ability to promptly enter into estivation (quiescence) whenever they experienced drying out of their environment. Snails rapidly suppressed their metabolism and minimized their water loss using discontinuous gas exchange pattern. The metabolic suppression probably included periods of tissue hypoxia and anaerobism as indicated by accumulation of typical end products of anaerobic metabolism: lactate, alanine and succinate. Though the drought-induced metabolic suppression was sufficient to stimulate moderate increase of supercooling capacity, the seasonally highest levels of supercooling capacity and the highest tolerance to subzero temperatures were tightly linked to hibernation (diapause). Hibernating snails did not survive freezing of their body fluids and instead relied on supercooling strategy which allowed them to survive when air temperatures dropped to as low as-21°C. No accumulation of low-molecular weight compounds (potential cryoprotectants) was detected in hibernating snails except for small amounts of the end products of anaerobic metabolism.