CHAPTER include tilapias, catfish and carp; however the African

CHAPTER ONE

 

1.0             
INTRODUCTION

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1.1       Fish 

Fish
as defined by Merriam-Webster is any of numerous cold-blooded strictly aquatic craniate
vertebrates that include the bony fishes and usually the cartilaginous
and jawless fishes and that have typically an elongated somewhat spindle-shaped
body terminating in a broad caudal fin, limbs in the form of fins when present
at all, and a 2-chambered heart by which blood is sent through thoracic
gills to be oxygenated.

The
role of fish as an important source of food, income, employment, as well as
recreation for people around the world cannot be underemphasized. Also, fish is
known as a very paramount source of animal protein for both man and livestock
in developed and developing countries.

Nigeria
as a developing country has a current demand for fish to be about four times
the level of local production. Humans consume approximately 80 percent of the
catch as food. The remaining 20 percent goes into the manufacturing of products
such as fish oil, fertilizers, and animal food (Ozigbo et al., 2014).

 

1.2       Fisheries and Aquaculture

Fisheries
and aquaculture are integral parts of agriculture which were found to have the
capacity to increase the country’s GDP (Gross Domestic Product) and can solve
the unemployment problem for our teeming youths if adequately managed (Ozigbo et al., 2014).

Aquaculture
is an embodiment of the overall agricultural production system in Nigeria. The
major species cultured in Nigeria include tilapias, catfish and carp; however
the African catfish Clarias gariepinus is the most farmed (Agbede et
al., 2003).

Clarias gariepinus
is one of the most resistant and widely accepted and highly valued fish that
could be cultivated in Nigeria, therefore the need for documented research on
pathogens which might constitute serious problems on this fish cannot be overemphasized
(Dankishiya and Zakari, 2007).

The
application of medicinal plants in aquaculture is gaining popularity in recent
years.  Ngo (2015) highlighted that the
application of medicinal plants which have been known as immunostimulants for
thousands of years as natural and innocuous compounds has potential in
aquaculture as an alternative to antibiotics and immunoprophylactics. He
further stressed that the growing interest in these plants has increased
world-wide because they are easy to prepare, cheap, and have few side effects
on animals and the environment.Also, medicinal plants show their main
properties as growth promoters, immune enhancers, where they act as
antibacterial and antiviral agents to the host immune system). This statement
is in agreement with the works of Reverter et
al (2014) that aquaculture is the main source to increase fish supply. Fast
development of aquaculture and increasing fish demand lead to intensification
of fish culture, magnifying stressors for fish and thus heightening the risk of
disease. Until now, chemotherapy has been widely used to prevent and treat
disease outbreaks, although use of chemical drugs has multiple negative impacts
on environment and human health e.g. resistant bacterial strains and residual
accumulation in tissue. Hence, disease management in aquaculture should
concentrate on environmentally friendly and lasting methods. Reverter et al (2014) also emphasized that
recently, increasing attention is being paid to the use of plant products for
disease control in aquaculture as an alternative to chemical treatments. Plant
products have been reported to stimulate appetite and promote weight gain, to
act as immunostimulant and to have antibacterial and anti-parasitic (virus,
protozoans, monogeneans) properties in fish and shellfish aquaculture due to
active molecules such as alkaloids, terpenoids, saponins and flavonoids.

Aquaculture
is one of the important sectors contributing significantly in the Nigerian
economy. For increased production and profit, fish farmers are encouraged
towards intensification of culture system. In such practice of fish/shrimp
farming, disease becomes major problem. Disease is one of the most important
problems of fish production both in culture system and wild condition of
Nigeria. Fishes have been suffering from many diseases such as epizootic
ulcerative syndrome (EUS), tail and fin rot, fungal, parasitic and bacterial
infections (Chowdhury, 1999). With the outbreak of EUS in 1988, Channa sp.,
Puntius sp., Anabas sp., Clarias sp., and other indigenous
species of fish are seriously affected (Barua et al., 1991). Thus to
prevent and control of fish diseases, treatment trials has become an essential
component of fish production.

Chemotherapy
has progressed internationally for treating the most diversified infectious
disease of fish (Shieszko, 1959). However, there are problems associated with
the use of such chemicals. It was the demand of the time to look for
alternative means of commercial synthetic drugs. Medicinal plants are vital source
of drugs from the ancient time holding the scenario of the Indian system of
medicine (Sharma et. al., 2009). According to Ghani (1998) medicinal
plants are rich sources of bioactive compounds and thus serve as important raw
materials for drug production. In Bangladesh, different kinds of medicinal
herbs are available which grow in roadside, small jungles are fellow lands and
most of them are cultivable with very low cost. The application of herbal
medicine has grown in laboratories and in papers with little field practice.
Some farmers have experienced this treatment method as crude extract of herbs
(Ha Thu et al., 2011). It is thus necessary to apply both the crude and
fine extract of herbs which can carry more specific and confirm use of herbal
medicine in laboratory and field at large scale. Thus the objective of present
study was to observe the use of various medicinal plant products against fish
diseases.

 

1.3       Medicinal Plants

Medicinal
plants have been used as sources of medicine in virtually all cultures (Baquer,
1995).

It
has been estimated that approximately 420,000 plant species exist on earth, but
for most of these, only very limited knowledge is available. Three approaches,
which are closely related to diet (foodstuffs), medical practice (folk and
traditional medicines), and scientific research (phytochemical analysis), can
be adopted to explore the value of medicinal plants/herbs. Based on the
experience from random trials and observations in animals, ancient people
acquired the knowledge of using herbs for treating illness (Samy et al., 2008).

The
drugs of today’s modern society are products of research and development, whose
raw materials are naturally occurring materials which are obtained from plants;
either in the roots stems, leaves, fruits and seeds (Odugbemi and Akinsulire,
2006; Burkill, 1994).

The
World Health Organization (WHO) has pointed out that traditional medicine is an
important contribution to its health goals. There are considerable economic
benefits in the development of indigenous medicine and in the use of medicinal
plants for the treatment of various diseases (WHO, 2003).

Medicinal
plants have also been of importance in the health care system of local
communities as the main source of medicine for the majority of the rural population.
Plants have not only nutritional value but also, in the eyes of the local
people, they have medicinal and ritual or magical values (Adewunmi et al., 2001).

Plants
have been a major source of medicine for human kind. According to available
information, a total of at least 35,000 plants species are widely used for
medicinal purposes. The demand for traditional herbs is increasing very
rapidly, mainly because of the harmful effects of synthetic chemical drugs. The
global clamor for more herbal ingredients creates possibilities for the local
cultivation of medicinal and aromatic crops as well as for the regulated and
sustainable harvest of wild plants. Such endeavors could help raise rural
employment in the developing countries, boost commerce around the world and
perhaps contribute to the health of millions (Anita, 2004).

Nigeria
is endowed with an enormous diversity of animals and plants, both domesticated
and wild, and an impressive variety of habitats and ecosystems. This heritage
sustains the food, medicinal, clothing, shelter, spiritual, recreational, and
other needs of her population (Odugbemi and Akinsulire, 2006).

Plants
have provided the basis for traditional treatment for different types of
diseases and still offer an enormous potential source of new chemotherapeutic
agent (Adewunmi et al., 2001). This
however requires extraction of the bioactive molecules of pharmacological
importance present following purification and identification procedures as well
as toxicological studies.

The
World Health Organization (WHO) estimates that herbal medicines provide primary
healthcare for approximately 3.5 to 4 billion people worldwide, and about 85%
of traditional medicine involves the use of plant extracts (Farnsworth, 2002),
which may be called “modern herbal medicine.”

Plants,
which constitute a major component of foodstuffs in humans, have formed the
basis of various traditional medicine systems and folk medicines that have been
practiced for thousands of years during the course of human history. Until now,
plants/herbs are still highly esteemed all over the world as a rich source of
therapeutic agents for the treatment and prevention of diseases and ailments;
at present, more than 35,000 plant species are used for medicinal purposes
around the world (Yirga, 2011). In conventional Western medicine, 50–60% of
pharmaceutical commodities contains natural products or is synthesized from
them; 10–25% of all prescription drugs contain one or more ingredients derived
from plants (Cameron et al., 2005).

Medicinal
plants have a long history of use in most communities throughout the world. In
Africa, people still consult traditional healers even when being attended to in
conventional orthodox clinics. The history of medicinal plants is widely
documented in various pharmacopoeias; Planta
medica, Napralert, etc, around the world. Unfortunately, little effort has
been made in transforming this vast knowledge using simple low cost
technologies. Apparently, a great number of rich unclassified indigenous
knowledge on the therapeutic ability of medicinal plants abounds in Africa that
has not been documented for possible modification and application by academia
to address the pressing problems of indigenous people on the African continent.

Most
plant parts (extract) identified such as (bark, 
roots, seeds, fruit and leaves) serve as major source of active
ingredient and products of secondary metabolites such as alkaloid, terpenoids etc
used in curing diseases, production of drugs as well as in maintaining good
health by both the traditional and orthodox medical practitioners (Nwachukwu et al., 2010).

Cowan
(1999) revealed that finding healing powers in plants is an ancient idea.
People on all continents have long applied poultices and imbibed infusions of
hundreds, if not thousands, of indigenous plants, dating back to prehistory.

Evans
(2005) highlighted that traditional medicine sometimes called herbalism is the
most ancient method of curing diseases. It has been known that plants are the
first and only true medicines ever used by man (Ariza et al., 2011). However, in Nigeria, until recently, the practices
of the use of herbs has been kept by secrecy and shrouded in dreaded magical
incantations, rituals and sacrifices. It is now very clear that the potency of
the plants and its parts does not depend on such exhibition.

The
use of plants for medical purposes is an important part of the culture and
tradition in Africa. The number of resistant strains of microbial pathogens is
growing since penicillin resistance and multi-resistance pneumococci caused a
major problem in South Africa in 1977 (Eloff, 1998; Marchese and Shito, 2001).
The development of resistance of antimicrobial agent has forced scientists to
search for antibacterial substance from alternative sources such as medicinal
plants. This has also made medicinal plants to receive much attention as an
alternative therapy as against synthetic drugs. Traditionally, extracts of Theobroma cacao (Cocoa) have been used
against Salmonellae (Busta and Speck,
1968) and against Escherichia coli
(Ariza et al., 2011).

Ariza
et al (2011) also addressed that
attempts to discover non-conventional antimicrobial agents with high
effectiveness and lower toxicity, have put great concern to plant extracts.

Phytochemical
compounds have been extensively studied to perform antibacterial and antifungal
activities. Extract of grape, turmeric and tea leaves have been demonstrated on
their antibacterial potency against various human pathogens (Sebai et al.,
2010; Zhang et al., 2010; Cui et al., 2012; Kawamoto et al.,
2012).

Different herbal plants or
combinations of them are known to have properties such as anti-stress, growth
promoters, appetisers, tonic and immuno-stimulants. Moreover, these substances
also possess other valuable properties; they are non-biodegradable and
biocompatible. No herbal-resistance immunity has been found by any pathogen
till today. Some of these herbs and herbal plants remedies have potent
anti-viral as well as anti bacterial and anti-fungal properties.      

Some
important advantages of herbal plants include their plenty availability and are
cheap; their action has been proven effective
with no adverse effect on natural ecosystem; they act as the substitution for
feed and fertilizer in aquaculture; they act as a growth promoter and
immunostimulant; herbal drugs act as a anti bacterial substrate with antimicrobial activity;
act as anti-fungal and anti-parasitic
agents (Citarasu,
2010)).

Medicinal plant has
been alternatively used to antibiotics in fish health management (Chakraborty
and Chattopadhya, 1998). These herbs are not only safe for consumers
but also widely available throughout Asia and other countries and they also
have a significant role in aquaculture (Direkbusarakom,
2004). Many studies have proved that herbal additives enhanced the
growth of fishes and also protected from the diseases (Sasmal et
al., 2005).

Various
herbal products such as Hygrophilas pinosa, with Hanias omnifera,
Zingiber officinalis, Solanum trilobatum, A. paniculata, Psoralea
corylifolia, Eclipta erecta, Ocimum sacnctum, Picrorhiza kurooa,
P. niruri, Tinospora cordifolia, Purified silajit and cod
liver oil have the characteristics of the growth promotion, anti-stress,
immunostimulation and anti-bacterial. This preparation had a good influence in
the Penaeus larvi culture (Citarasu et
al., 2002). Livol (IHF 1000) is a commercial herbal growth
promoter which has been found to significantly improve digestion thereby
leading to better growth, production and health in cultivable fishes. The
herbals/spices in the diets induce the secretion of the digestive enzyme. It
will result in stimulating the appetite and increasing food consumption
and efficiencies. The growth promoter characteristic herbs induce the
transcription and lead to high protein synthesis. Livol (IHF-1000) is a herbal
growth promoter containing different plant ingredients such as Bohaevia diffusa,
Solanum nigrum, Terminaelia arjuna, Colosynth and black salt and
has been found to significantly improve digestion, thereby leading to better
growth, production and health in cultivable fishes. Papaya leaf meal contain an
enzyme namely papain which increases the protein digestion, food conversion
ratio, specific growth rate and weight gain in the 16% unsoaked papaya meal
diet fed to P. monodon post-larvae. Herbal growth promoters help to
induce the transcription rate. This process leads to increase RNA, total amino acid, finally increases production of proteins
in the cells.

Herbal drugs act as immunostimulants due
to the active biochemicals such as alkaloids, flavanoids pigments, phenolics,
terpenoids, steroids and essential oils. Immunostimulants are substances, which
enhance the non specific defense mechanism and provide resistance against
pathogenic organisms (Citarasu et
al., 2002, 2006).
Many plant-derived compounds have been found to have non-specific
immuno-stimulating effects in animals, of which more than a dozen have been
evaluated in fish and shrimp (Citarasu et
al., 2006; Sakai, 1999).
The better performance of haematological, biochemical and immunological
parameters were found immunostimulant incorporated diet fed to shrimps (Citarasu et
al., 2006). The best example is the herb Picrorhiza kurroa used as an antistress compound for shrimps.

Bacterial
organisms are responsible for the major infectious disease outbreak in fish
farms and these have been on for over the years. Control of fish disease is
currently based almost entirely on chemotherapy. Anti-bacterial chemotherapy
has been applied in aquaculture for over 50 years (Inglis, 1996). Antibiotics
are also used prophylactically in carp culture at times of year when
haemorrhagic septicaemia is most likely to occur (Inglis et al., 1994).
But habitual use of anti-bacterials can lead to problems with bacterial resistance
and unacceptable residues in aquaculture products and environment. The
resistant bacterial strains could have a negative impact on the therapy of fish
diseases or human diseases and (environment of fish farms (Smith et al., 1994).
This situation actually brings human to new medical dilemma Muniruzzaman and
Chowdhury, 2004).

However,
medicinal plants possess therapeutic properties; exert beneficial
pharmacological effects on the animal body, widely available in nature and
eco-friendly. A scientific study to investigate the antibacterial activity of
the medicinal plants, guava (Psidium guajava) against bacteria
pathogenic for shrimp was initiated by Direkbusarakom and Aekpanithanpong
(1992). Kraus (1995) found that extract of neem fruit, seeds, seed kernel,
twigs, stem bark and root have fungicidal and bactericidal properties.
Externally garlic (Allium sativum) is used as disinfectant and it is
applied to indolent tumours, ulcerated surface and wounds (Dastur, 1977).
Chowdhury et al. (1991) reported that extract obtained from garlic was
also highly effective against two tested bacteria, A. hydrophila and
P. fluorescens (MIC 0.6 mg/ml).

Although
several works have been done on the use of medicinal plants in curing fish
diseases in Nigeria but little works have been done in this aspect with the use
of cocoa and its various parts to treat fish diseases.In view of this, the
study is aimed at evaluating the in-vitro
efficacies of the different parts of cocoa plants on bacterial organisms
isolated from catfish and also to evaluate the efficacies of some selected
synthetic drugs on some pathogens of C.
gariepinus.

 

1.4             
Justification for the Study

Fish
culture in Nigeria has a great potential. However, the country is still unable
to bridge the gap in the short fall between total domestic fish production and
the total domestic demand. In Nigeria, total domestic fish production is far
less than the total domestic demand. This may be as a result of less fish being
realized from aquaculture in consequence of diseases of fish which might have
reduced the total fish expected as a result of moribund.

 

1.5       Objectives of the Study

1.5.1
   Broad Objective

The
broad objective of this study was to evaluate the in vitro antibacterial effects of some cocoa plant parts extracts (Theobroma cacao) and some selected
synthetic drugs on fish pathogens isolated from African mud catfish, Clarias gariepinus (Burchell, 1822).

 

 

1.5.2
   Specific Objectives

The
specific objectives however, were

       
i.           
To identify quantitatively, phytochemicals
from parts of the cocoa plant.

      ii.           
Determine the sensitivity of
antibacterial effects of parts of cocoa, Theobroma
cacao plant extracts and some selected synthetic drugs on pathogens of
African mud catfish, C. gariepinus.

    iii.           
To compare the therapeutic effects of
the plant parts extracts with the selected synthetic antibiotic as control on
pathogens of African mud catfish, C.
gariepinus

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