ABSTRACT
This experiment was conducted to study the dynamics of
ions in the haemolymph of Giant African land snails (Archachatina
marginata) during fasting. Fourty Archachatina marginata were purchased
and using a completely randomized design (CRD) they were arranged into
four different treatments. Haemolymph was collected randomly from three
samples within each treatment and the samples were analyzed for
electrolytes which include sodium, bicarbonates, chlorides, creatinine,
calcium, phosphate and potassium. For sodium there was significant
difference in its concentration in the haemolymph from week 3 to week 6
(P<0.05) with the lowest concentration in week 6 and the highest in
week 3. For bicarbonate significant difference (P<0.05) in the
concentration of the haemolymph was only noticed from week 0 to week 3
with the lowest concentration found in week 9 and the highest in week 0.
There was significant difference (P<0.05) from week 0 to week 9 in
the concentration of haemolymph chloride with the lowest concentration
found in week 6 and the highest in week 3. There was no significant
difference (P>0.05) in the concentration of creatinine through the 9
weeks of the study. Calcium concentration had no significant difference
(P>0.05) from week 0 to week 3, the lowest concentration was found in
week 6 and the highest week 3. Phosphates concentration had no
significant difference (P>0.05) from week 0 to week 9 with the lowest
concentration found in week 9 and the highest in week 6. Fasting had no
significant difference (P>0.05) on the concentration of potassium
through the 9 weeks of the experiment the lowest concentration was found
in week 9 and the highest week 0. From this study fasting had no effect
on the phosphate and creatinine concentration of the haemolymph of
Archachatina marginata, but with effect on sodium, bicarbonate,
chloride, potassium and calcium.
.
TABLE OF CONTENT
Title----------i
Abstract---------ii
Acknowledgement-------iii
Certification--------v
Dedication--------vi
Table of Content-------vii
List of Tables--------ix
List of Figures--------x
CHAPTER ONE
1.0Introduction-------1
1.1Justification of study------2
1.2Objective of the study------4
CHAPTER TWO
Haemolymph-------6
Sodium-------6
Potassium-------7
Bicarbonate-------8
Chloride-------8
Serum creatinine------8
Calcium-------9
Inorganic phosphate------9
CHAPTER THREE
Materials and Methods-----10
3.1Experimental site, animals and methods----10
3.2Collection of haemolymph------11
3.3Chemical analysis-------11
3.4Statistical analysis-------12
CHAPTER FOUR
4.0 Results---------13
CHAPTER FIVE
5.0 Discussion--------28
CHAPTER SIX
6.0Conclusion------- -30
6.1Recommendation-------30
Reference--------31
LIST OF TABLES
Table 1: Blood test range for some animals----5
Table
2: Variation of ions in the haemolymph of giant African land snail
(Archachatina marginata) during a nine week fasting period-27
LIST OF FIGURES
Figure 1: Graph showing changes in the haemolymph sodium concentration of Archachatina marginata after 9 weeks of fasting.----14
Figure
2: Graph showing changes in the haemolymph bicarbonate concentration of
Archachatina marginata after 9weeks of fasting.----16
Figure 3:
Graph showing the changes in the haemolymph chloride concentration of
Archachatina marginata after 9 weeks of fasting.---18
Figure
4: Graph showing the changes in the haemolymph creatinine concentration
of Archachatina marginata after 9 weeks of fasting.---20
Figure
5: Graph showing the changes in the haemolymph calcium concentration of
Archachatina marginata after 9 weeks of fasting.---22
Figure 6:
Graph showing changes in the haemolymph phosphates concentration of
Archachatina marginata after 9 weeks of fasting.---24
Figure 7:
Graph showing changes in the haemolymph potassium concentration of
Archachatina marginata after 9 weeks of fasting.---26
CHAPTER ONE
1.0INTRODUCTION
Snail
is the common name that is applied most often to land snails,
terrestrial pulmonate gastropod mollusks. However the common name snail
is also applied to most of the members of the molluscan class gastropoda
that have coiled shell that is large enough for the animal to retract
completely into (Wikipedia.com. 2012). Snails are invertebrates which
mean that they lack a backbone. They belong to a large and highly
diverse group of invertebrates known as the Phylum mollusca (also known
more commonly as ‘mollusks’). The Phylum mollusca include slugs, clams,
oysters, mussels, squids, octopuses and nautiluses, in addition to
snails (About.com. 2012).
They belong to the class Gastropoda.
Gastropoda are a major part of the phylum mollusca and are the most
highly diversified class in the phylum. Snails belong to the order
stylommatophora (Fryda et al, 2005). Snails are terrestrial and marine
shell-bearing animals of approximately 80,000-100,000 species of the
phylum Mollusca (Cooper and Knowler, 1991). They are the second largest
phylum in the animal kingdom. Europe and Africa are two important
regions notable for snail production and consumption involving mainly
the snail families Helicidae and Achatinidae, respectively. However, the
giant African land snails Achatina achatina and Archachatina marginata
are the most popular edible snails in the West African high forest zones
(Ogunsami et al., 2003, Cobinah et. al, 2003).
During dry
spells free-living snails withdraw into their shells and conserve water
by sealing the shell opening with an epiphragm and aestivate by reducing
mobility reproductive behaviour and growth. Water loss is further
retarded by the use of discontinuous breathing pattern; the pneumostome
opens intermittently to allow a rapid exchange of CO and O (Hermes-lima
et. al, 1998). When humidity falls below 75% (as witnessed during the
dry season: October to Mid-March in West Africa), A. achatina becomes
inactive and seals itself into its shell with a white calcareous layer
and aestivates in order to prevent loss of water from the body
(Omoyakhi, 2007). A. marginata were observed to form epiphragm more
readily and replace them more frequently than A. achatina (Omoyakhi,
2007). Snails are said to survive many months without food and water
under aestivation (Akinnusi, 1998). The aestivated snails draw on their
reserve of fat and glycogen at much reduced rate, which implies an
imminent reduction in weight and loss of valuable growing time as growth
during aestivation is said to reduce.
The success of gastropod
molluscs in terrestrial habitats has been due to various structural,
physiological and behavioural specializations (Riddle, 1983). One
specialization that is well developed among the pulmonate land snails is
the capacity to enter the dormant state of aestivation during periods
of hot and dry environmental conditions (Rees and Hand, 1993). Snails
can be found in a very wide range of environments, including ditches,
deserts, and the abyssal depths of the sea. Although many people are
familiar with terrestrial snails, they are in the minority. Several
species of the genus Achatina and related genera are known as giant
African land snails (GALS); some grow to 15 in (38 cm) from snout to
tail, and weigh 1 kg (Frederick, 2010).
1.1Justification of Study
Haemolymph
is the blood analogue found in all arthropods and most molluscs which
have an open circulatory system (Ebroadcast.com 2012). It is composed of
water, inorganic salts (mostly Na, Cl, K, Mg and Ca) and organic
compounds (mostly carbohydrates, proteins and lipids). Muscular
movements by the animal during locomotion can facilitate haemolymph
movement, but diverting flow from one area to another is limited
(Harris, 2000). Responses to high or low temperatures in the snail
induce aestivation and hibernation.
The haemolymph is an
important medium for the transport of nutrients to and wastes from
various organs of the snail. Aestivation, being a structural,
physiological and behavioural response to desiccation, probably plays a
role in the dynamics of haemolymph changes in land snails as haemolymph
ionic concentration is said to show seasonal fluctuations, strongly
influenced by hydration, feeding and acid/base balance (Langley, 2004).
There are limits to the duration of aestivation that can be tolerated by
land snails and mortality eventually increases as aestivation is
prolonged (Rees and Hand, 1993). Comprehensive values of haemolymph
ionic parameters for the giant African land snails are now popularly
reported in literature but none for fasting snails. Reference range
values for haemolymph ionic parameters from non-aestivating, aestivating
and fasting Archachatina marginata could therefore be useful for
assessment of physiologic and pathologic alterations in wild as well as
captive snails and establish their possible application in the
evaluation of health and disease status. The information may also be
useful in domestication, management and bio-conservation initiatives
involving this species.
1.2Objective of the study
This research therefore studied dynamics of the haemolymph ionic composition of the Giant African land snail during fasting.