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“CHAPTER ONE

INTRODUCTION

1.1 background of the study

The consistently expanding worldwide lighting from artificial light sources

has worked up assorted investigates on their effects on the physiological, conduct,

neurological working of widely varied vegetation assets of the biological system

(Dominoni et al., 2013). The main stimulus for controlling circadian rhythms,

seasonal cycles, and neuroendocrine responses is ambient light, according to

animal research conducted over the past few years (Aschoff, 1981; Binkley, 1990;

Reiter, 1991).

The primary energy source on Earth is light. Based on its characteristics and

behavior, light is divided into different wavelengths. Different characteristics of

light include interference, diffraction, reflection, refraction, polarization, and

reflection. Different light wavelengths make up electromagnetic radiation. Single-

wavelength light sources are known as monochromatic lights, where mono stands

for only one and chroma for color. Monochromatic lights are defined as visible

light that falls inside a specific range of wavelengths. It has a wavelength that falls
within a constrained wavelength range. These lights can be identified by their level

of brightness, hue, polarization, and propagation direction.

For physics, Monochromatic light, which only has one color, is often created

when excited atoms encourage photon emission. The Greek words "mono" and

"chromos" are the origin of the word monochromatic. Mono signifies only one,

while chromos refers to color. The frequency and color of the light are typically

determined by the energy level and wavelength of the photons that are released.

The wavelength of the photons in monochromatic light fall within the region of the

electromagnetic spectrum known as visible light, which is readily observable by

human eyes. Numerous fields, including astronomy, forensic science, and

astrophysics, can benefit from the usage of monochromatic lighting.

1.2 STATEMENT OF PROBLEM

The animal protein intake of Nigerians is very low and this has led to an acute

malnutrition amongst the greater percentage of the rural populace (Ajacin et al.,

2017). Bierjee., (2004). reported that the protein consumption in Nigeria is below

67g recommended by the world health organization.

However, one problem facing the rearing of snail is formulating an improved diet

that will meet the nutrient requirement of snails. In order to do this successfully,
attention has been drawn to protein, because it plays important role in growth,

maintenance, hormonal and enzymatic activities.

It is based on this backdrop that this study is out to access the impact of

monochromatic lights on the growth and proximate composition of Achatina

achatina

1.3 JUSTIFICATION

Several studies have been conducted on different kinds of snails but has not been

conducted on Achatina achatina specifically. For example, Adebesin and

Ojeabulu(2013) studied the effect of different light component on the growth of

Giant African Snail which enable them find out that the snails exposed to blue light

has the highest weight gain, followed by those in dark chamber, while those in

yellow light had the least (Bierjee, 2004)

Anupam, et al. (2013), also studied the behavioural response of Lynmanea

accummaniata towards different light sources and found that light spectral and

intensity has significant effect on the snail.

1.4 AIM

The aim of this research is to determine the effects of different monochromatic

lights sources on the growth rate performance and behavioral pattern of Achatina

achatina.
1.5 OBJECTIVES

1. To evaluate the effect of growth rate dimensions and weight gained of the

snails

2. To determine and evaluate the proximate composition of Achatina achatina.

LITERATURE REVIEW

2.1 HISTORICAL BACKGROUND

Roasted snail shells have been found in archaeological excavations, an indication

that snails have been eaten since prehistoric time (Rebecca and Sheldon, 2004).The

act of farming snail was presumed to have started about 50 B.C when snails were

raised in small fattening units called cochlear garden. Snails belong to the phylum

mollusca, which is the second largest invertebrate.

The group is characterized by the possession of shell. They may also be aquatic,

terrestrial or amphibians. Snail is one of the mini-livesstock that has recently

attracted attention among agriculturists and farmers in Nigeria as an after- math of

alarm raised by Food and Agricultural Organization (FAO) on animal protein

deficiency among Nigerians (Adesope 2000; Akinnusi, 2000).

The snail (especially the African giant land snail Archachatina marginata) is

mostly found in Nigeria and it is an excellent source of animal protein. It is one of

the biggest sized specie of snails and it lays large sized eggs, which ranges from 5-

15 eggs per clutch. Snail meat is nutritiously high up to 60% protein on dry matter

basis, rich in essential amino acid like lysine, leusine, isoluceine,

(Imevbore, 1990; Stievenart, 1992; Ebenebe, 2000). The species of snails that are

common in temperate regions are: Helix aspersa, Helix pomatia, Helix Lucorum,

Helix cibeta, Helix adqnensis, Helix anctostoma, Helix melanostoma, Helix

melanonixia, Helix thiessiana, Helix muculam, Helix asperta, Iberus alonensis,

Arianta arbustorium, Cepaea nemoralis, Cepaea hortensis, Theba pisana, Otala

puntata, Otala lacteal, Perforatolla incarnata, Sphincterochila candidisma. The

species that are common to tropical African include Achatina achatina, Achatina

fulica, Archachatina ventricosa, Archachatina marginata, Archachatina degneri,

Limicolaria martensis and Macrochilamys indica. Achatina achatina is considered

highly promising in providing animal protein due to its high egg laying capacity.

2.2 MATING AND EGG LAYING

Snails are hermaphrodites. They have both male and female reproductive organs

but must mate with another snail of the same species before they lay eggs. Some

snails may act as males one season and as females the next season (Rebecca and

Sheldon, 2004). Other snails have been identified to play both roles at once and

fertilize each other simultaneously. Mating is preceded with a courtship that

involves the suitor piercing the body of the other individual with a simulating dart.

This can sometimes be seen as a white splinter sticking out of the skin. Giant

snails begin breeding when about a year old and mating occurs in the late spring or
early summer after several hours of courtship. Second mating sometimes occur in

the summer.

The biggest ecotype of snail species should be used for breeding. They should not

have broken or perforated shell and should be healthy snails. Amusan and Omidiji

(1998) observed that fullness of flesh within the shell is an indication of good

health and that healthy snails cannot withdraw its body far into the shell when

irritated but the starved or those not in good condition withdraws its body far into

the shell.

In tropical climates, mating may occur several times a year. After mating, the snail

can store sperm received for up to a year but it usually lays eggs within few weeks.

Snails are sometimes interested in mating with another snail of the same species

that originated from considerable distance away (Rebecca and Sheldon, 2004).

Achatina achatina can lay between 100 -500 eggs per clutch. The eggs are

elliptical and measure about 5mm long. They are usually laid in roundshaped holes

dug 2-5cm deep in the soil but are occasionally laid on the soil surface. The

incubating soil are also needed to be kept moist but not wet, maintaining a

temperature of 25-28 degree centigrade and relative humidity of above 80%

(Amusan and Omidiji, 1998). If the eggs are exposed to heat, it will dry and harden

and therefore will not hatch. They usually hatch 25-30 days after laying. One to
three days are required to complete hatching of each egg clutch and the size of the

hatching depends on the size of the egg (Stievenart, 1996). Ejidike et al (2002),

observed that hatchability is affected by dry soil which adversely affect incubated

snail eggs, thereby reducing hatchability of the eggs. Younghatchlings are

normally kept in small baskets with tiny holes to avoid escape until they grow into

bigger sizes.

2.3 GROWTH OF SNAILS

Some snails grow faster than others within the same snail population and under the

same conditions. Some will take longer time to mature. The long maturity period

has been suggested to help the species survive harsh weather condition. Several

factors can greatly influence the growth of snails. The factors include as follows:

population density, stress such as noises, light, vibration, unsanitary conditions,

irregular feedings, being touched etc., feed, temperature and moisture, and the

breeding technology used. Adeparusi (2001) reported a reduction in growth rate of

Archachatina marginata during the adverse condition of hamattan. They obviously

went into aestivation with storage of water and a covering of epiphragm to prevent

such external influence. He reported that a broken epiphragm was rapidly rebuilt in

2-3 days, while it takes two weeks for a broken epiphragm to disintegrate.
The snail farmers had always sought after the appropriate inclusion of calcium on

snail diet. Thompson and Cheney (1996) reported that 40% limestone flour

promoted good growth in Helix aspersa. Daouda (1993) used 15% oyster shell for

growing Achatina achatina. Amubode and Ogogo (1995) also used 70% bone

meal and 30% Oyster shell in diets for Archachatina marginata. Low calcium

intake will slow the growth rate and cause the shell to be thinner. Rebecca and

Sheldon (2004) reported that snails may eat paint or attack walls of buildings and

even eat dirt while seeking calcium.

A newborn’s shell size depends on the egg size since the shell develops from the

egg’s surface membrane. As the snails grow, the shell is added onto in increments.

Eventually the shell will develop a flare or reinforcing lip at its opening. This

shows that the snail is now mature, and there will be no further growth. African

giant land snails can live for 5 to 6 years although, just a few manage to live up to

15 years before they die (Akinomide, 1997). Growth is actually measured by shell

size, since a snail body weight varies and fluctuates, even in 100% humidity.

The growth rate varies considerably between individuals in each population group.

Adult size, which is related to the growth rate, also varies, thus the fastest growers

are usually the largest snails. Eggs from larger, healthier snails also tend to grow
faster and thus larger. Dryness inhibits growth and even stops activity. When it

becomes too hot and dry in summer, the snail becomes inactive, seals its shell and

aestivates until cooler, moister weather returns.

2.4 FEEDING

African giant land snails are considered as omnivorous animal based on their

eating habit. They are known to feed on decaying materials such as dead plants and

animals carcasses; thus, they are termed as good end-converters (Scavengers) like

pigs. They also feed on their own wastes (coprophagia) and eat up their dead or

weak mates under certain conditions (cannibalism). Some of the plant materials

which they feed on include; tubers: such as carrots, cocoyam, yam, and sweet

potato; fruit such as avocado pear, guava, oil palm, ripe paw paw, ripe plantain,

pineapple, orange, mango and bread fruit. Other materials include; plant leaves

such as paw paw, sweet potato, and cocoa yam, fluted pumpkin and household

waste: yam peel, cassava, bread, remnant foods without table salt, rotten plantain.

Amusan and Omidiji (1998) pointed out that snails when fed waterleaf soon lose

weight, become inactive with higher incidence of cannibalism and death. However,

the growth obtained through feeding young Archachatina marginata on plant food

materials supplemented with compounded feed was significantly better than that
obtained through feeding it only plant food materials (Ejidike et al., 2002). The

growth of snails like other animals differs with respect to what they are fed. There

is also a strong and positive relationship between nutrient content of the feed and

growth of snails (Okonkwo et al., 2000).

Adu et al (2002) pointed out the need for research studies on the use of

compounded ration for snail in order to solve the problem of scarcity of fruits,

tuber and leaves during the dry season. The provision of adequate feed (Okonkwo

et al., 2000), supplementary

vitamins, calcium, minerals and water during the dry season is capable of

thwarting the aestivation cycle and enhances greater productivity besides

preventing drug wastage and bacteria growth over time. Amusan and Omidiji

(1998), pointed out the need to avoid salt in snail feed since it possibly coagulates

the slimy salivary systems and deadens the foot/flesh of the snail resulting in

instant death.

2.5 CANNIBALISM BY HATCHLINGS

The first snails to hatch eat the shells of their eggs. This gives them needed

calcium for their shells. This may make them to start eating unhatched eggs. If the

optimum temperature for hatching is maintained, most eggs will hatch within 1-3

days and cannibalism will be low. Cannibalism may increase if hatching extends
over a longer period. Some of the eggs eaten are those that are not fertile or those

that did not develop properly. Sometimes, properly developing embryos might be

eaten. High density clutches of egg masses increases the rate of cannibalism, as

after newly egg masses are more likely to be found and eaten. Snail eggs are highly

proteinous and this helps the baby to start developing quickly and be healthier.

Cannibalism is also common among adult snails fed mineral deficient diets. Ireland

(1991) reported that mortality occurred only in snails fed lower calcium diets.

However, this mortality must have resulted from cannibalism due to mineral

deficiency.

2.6 PREDATORS, PARASITES AND DISEASES

A snail farmer must be aware of predators, parasites and diseases of snail in order

to reduce mortality to the barest minimum The predators of snail include the field

mice, rats, frogs and toads, domesticated birds such as ducks and turkeys, lizards

and snakes, beetles, millipedes and centipedes. The frogs have been observed to

take only the young snails while the reptiles eat both the eggs and the snails. Using

cover nets over the pens can prevent bird predation. Other predators can be kept

out of the pen by building fences between 15 and 30 cm high and digging well into

the groundaround the pens. Left over feed must always be removed regularly from

pens since some predators like rat and field mice are attracted by the uneaten feed.
A fly, Alluaudihella flavicarous has been identified as the major parasite on snails.

This fly belongs to the same family as the housefly and the adult resembles the

adult housefly. The fly lays 20-40 eggs in the snail’s shell or on the snail. The eggs

hatch in about 1 week and the small, cream-colored worms start feeding on or in

the body tissue. They feed until the body is reduced to a putrefying mass, and then

pupate within the shell. After a 10-day incubation period, the adults emerge.

Snails can best be protected against these flies by covering the pens with nylon

mesh. Ectoparasitie mites are also found on the snails in hutch boxes. These appear

to be secondary parasites usually occurring on inactive snails. Obi et al (2001)

identified several entero-pathogenic bacteria and fungi among African giant land

snails around Ibadan metropolis. Akinomide (1997) also reported that bacteria,

particularly entero-bacteria may be transmitted to people who handle or eat snails.

In Italy today wild snails are no longer considered as a food source as stringent

health regulation for consumption of food are now in place (Sonya Begg, 2003).

This is necessary to protect the consumer against collected snails that may have

ingested toxic plants or potentially harmful chemicals.

Two major diseases have been identified to attack snails. The first disease is a

bacterial diseases caused by pseudomonas. This leads to intestinal infections,

which may spread rapidly amongst dense populations of snails. The second disease
is caused by fusarium, which parasitizes the eggs of snails. The affected eggs turn

reddish brown and development stops. This disease is referred to as rosy egg

disease. Basic hygiene is known to prevent the spread of diseases. Pens should be

cleaned out regularly to remove excreta and uneaten feed, as well as any other

decaying matter that may serve as substrate for pathogenic organism.

The soil in the hutch boxes should also be sterilized. Akinomide (1997) suggested

that newly purchased snails should be given an alum, lime or lemon solution bath

before

Finally bringing them in since the astringent property of the solution reduces the

level of snail ecto-parasites and keeps them clean.

2.7 CLIMATIC CONDITIONS AND SOIL CHARACTERISTICS

All the countries in which Archachatina marginata is established have tropical

climates with warm, mild year round temperatures and high humidity (Raut and

Barker, 2002). The species occurs in agricultural areas, coastal areas and wetlands,

natural and planted forests, riparian zones, scrublands and urban areas (Raut and

Barker, 2002). These snails thrive in forest edge, modified forest and plantation

habitat (Raut and Barker, 2002).

humidity (75% to 95%) is best for snail farming, though most varieties can stand a

wider range of temperatures. Humidity that is lower than required will disturb the

production due to excessive evaporation from the body of the animal. Such a

condition can lead to emergence of illness and can cause death. They pointed out

that the optimal temperature is 70oF for many varieties. When the temperature falls

below 45oF, snails hibernate. Under 54oF, the snails are inactive and under 50oF,

all growth stops. When the temperature rises much above 80oF or conditions

become too dry snails estivate. Wind accelerates moisture rise in snails.

Therefore, to prevent snails from drying, snaileries should be situated in sites,

which are protected from the wind since it affects the humidity and temperature of

the environment. Also, wind can be held by planting big trees around the Farm.

Trees apart from reducing the wind can also provide shade and increase the

humidity. Snails also need damp, not wet environments. Although snails need

moisture, wet, or water logged, soil must be drained to make it suitable for them.

Snails breathe air and may therefore be drowned in overly wet surroundings.

Rebecca and Sheldon (2004) reported that snails need soil at least 3 inches deep in

which to lay their eggs. Dry soil is not suitable for the preparation of a nest, nor is

soil that is too heavy. In clay soil that becomes hard, reproduction may decrease
because the snails are unable to bury their eggs and the hatchlings have difficulty

emerging from the nest. Hatchability of eggs also depends on soil temperature, soil

humidity, and soil composition. Soil consisting of 20% to 40% organic material is

good (Rebecca and Sheldon 2004).

Ejidike (2002) reported that snail soil tolerance differs and that while some species

prefer acid soil of low pH of about 4.5, most of them prefer slight alkaline soil with

a pH range of 7.0-8.0. Snailery soil is often considered as a good breeding site for

most infectious microorganisms and pest of land snails. Therefore, snailery soil is

advised to be heat treated either wet or dry. Sterilization is necessary to destroy soil

ants and their eggs because of the devastating nature of these ants on snails.

Akinomide (1997), advised that the use of disinfectants or other chemicals is better

avoided to prevent toxicity or drug accumulation within their body since they are

in frequent contact with the soil and often taking in soil particles. He further

emphasized that periodic heat treatment of the soil should be carried out twice a

year or when some ants or pests are sited therein.

2.8 FEEDING PATTERNS

At various stages of Growth Snails generally consume about 3-4 % of its body

weight of feed, per day (Amusan and Omidiji 1998). The feed must be balanced to

include a combination and in right proportions of carbohydrate, fat and oils,

hatchlings are always fed powdered formulated ration, very soft leaves, ripe fruits,

mashed feeds, pasty feeds, or a combination of them. However, they prefer

powdered formulated ration at that tender age. Snail feed is generally

supplemented with lime since it is necessary for their shell development. Lime is

also required in a period preceding the sexual maturity stage in order to prepare the

animal for egg- production and shell development. It also helps to recover the shell

damages caused by either crashes or egg laying activities.

3.0 MATERIALS AND METHOD

3.1 LOCATION AND DURATION OF STUDY

3.2 EXPERIMENTAL DESIGN

The experimental design was completely randomized design (CRD). The

treatments were formed based on the type of light the snails were subjected to

(blue, green, red, yellow). The four treatments were labeled treatment A(a1,a2,a3

for blue light), B(b1,b2,b3 for green light), C (c1,c2,c3 for red light) and

D(d1,d2,d3). The snails in each group were subjected to 12hours of light and

12hours of darkness but the control group identified by letter K was completely

kept in total darkness which mimicked the natural environment of the snails.

3.3 PROCUREMENT OF EXPERIMENTAL ANIMALS

Fourty grower snails (Achatina achatina) of average weight were got from a local

snail trader at Anyigba market, Kogi state. They were transported in well aerated

jute bag from the place they were procured to the experimental site. The jute bag

used in the transportation contained little garden (loamy) soil to reduce the stress of
transportation. They were protected from direct rays of sunlight during

transportation. The jute bag was placed in a bowl to reduce heat from the vehicle.

3.4 ACCLIMATIZATION OF THE EXPERIMENTAL ANIMALS

On arrival, the snails were placed in their improvised housing which is a basket.

The snails were covered very well to prevent them from escaping. After two days,

they were placed in the plastic bowl which was covered with a mosquito net and

tied with a twine rope to prevent the snails from escaping and also prevent pests

and predators from attacking the snails. The bowls were filled with one third of

sterilized loamy soil got from the farm. The snails were fed with paw-paw leaves

and plantain leaves during the one week of acclimatization.

3.5 EXPERIMENTATION AND DATA COLLECTION

The (Achatina achatina) were divided into 4 groups of snails and 3 replicates in

cages equipped with feeding and drinking troughs. At each treatment, pawpaw

leaves were placed in the containers where the snails were kept for experiment as

feed for the snails. These were previously weighed as well as the remnant using a

0.5 g precision scale. They were regularly cleared of dead animals and faeces to

avoid the development of possible pathogens. The dead animals were inventoried

by treatment and replaced by those of similar age and weight. At the beginning of
the test, the snails were weighed and shell measurements made using a 0.05 mm

precision digital caliper. The animals were monitored for 14 days

3.6 DATA COLLECTION

Feed intake and weight gain were measured using sensitive weighing balance

(electronic kitchen scale). Data on the behavioral pattern was collected everyday

by closely observing the snails 2 hours in the morning, afternoon and night.

3.7 STATISTICAL ANALYSIS

The data collected were subjected to Analysis of variance (ANOVA) using SPSS

analytical package and significant means were separated using Duncan’s New

Multiple Range test, at 5% probability level.