ABSTRACT
This study
investigated the effects of thyme (Thymus vulgaris) and varying dietary protein
levels on the physiological characteristics of Nigerian local cocks. The
primary focus was to evaluate the impact of thyme supplementation on semen
characteristics, libido, haematology, serum biochemistry, seminal plasma
composition, organ weights, and overall weight performance of the cocks.
Thirty-six matured Nigerian local cocks aged 48–50 weeks, with an average
weight of 1.08–1.80 kg, were utilized for the experiment. These birds were fed
diets containing different levels of thyme leaf meal (5 g/kg, 10 g/kg) and
dietary protein (18%, 21%) under controlled conditions.
Thyme leaf
meal was prepared by grinding dried thyme leaves into a fine powder. Semen was
collected using the abdominal massage technique, and its characteristics, such
as volume, pH, consistency, motility, and sperm viability, were assessed
immediately. Libido was determined by observing mating behaviors in response to
mature hens. Other parameters evaluated included haematological and serum
indices, relative organ weights, and testicular tissue histopathology.
Statistical analysis was conducted using one-way and two-way ANOVA, and mean
differences were separated using Duncan’s multiple range test.
Results
revealed that diets supplemented with 5 g/kg thyme and 18% dietary protein
significantly enhanced semen quality, including volume, pH, consistency,
progressive motility, and sperm viability, while reducing abnormal sperm cells.
These improvements were also accompanied by higher libido scores. In terms of
weight performance, cocks fed 10 g/kg thyme and 21% protein levels achieved
significant weight gains (up to 2.016 kg), demonstrating a positive impact on
market size.
Haematological
and serum indices showed no deleterious effects at moderate thyme
supplementation levels (up to 10 g/kg) over a 30-day period, indicating the
safety of these inclusion levels. However, prolonged feeding with higher
inclusion levels may impact red cell indices and sperm quality negatively. The
findings support traditional claims regarding thyme’s aphrodisiac and
antioxidant properties, highlighting its potential to improve male fertility
and reproductive performance.
In
conclusion, this study confirms the effectiveness of thyme leaf meal and
dietary protein supplementation in enhancing semen quality, libido, and weight
performance in Nigerian local cocks. It recommends incorporating 5 g/kg thyme
with 18% dietary protein for optimal reproductive outcomes and 10 g/kg thyme
with 21% dietary protein for improved weight performance. Caution is advised
with prolonged use of high inclusion levels. Further research on hormonal
changes, including testosterone levels, is suggested to provide a comprehensive
understanding of thyme’s effects.
These
findings underscore the potential of thyme as a cost-effective dietary
supplement to improve the productivity and reproductive efficiency of Nigerian
local cocks, contributing to enhanced poultry production and food security.
TABLE OF CONTENTS
CHAPTER 1
INTRODUCTION
1.1 Background of the Study
1.2 Statement of Problem
1.3 Objectives of the Study
1.3.1 Specific
Objectives
1.4 Justification of the Study
CHAPTER 2
LITERATURE REVIEW
2.1 Definition of Poultry
2.2 Anatomy of Cocks
2.3 Stages of Spermatogenesis
2.4 Physiology of Sperm Production
2.5 Functions of the Accessory Sex Glands in
the Cockerel
2.6 Cockerel Semen Composition
2.7 Semen Quality
2.8 Factors Affecting Semen Production
2.8.1 Season
2.8.2 Ambient Temperature
2.8.3 Photoperiod or Day Length
2.8.4 Nutrition
2.8.5 Disease
2.8.6 Body Weight of the Cockerel
2.9 Semen Collection
2.9.1 Abdominal Massage Technique
2.10 General Evaluation of Poultry Semen
2.10.1 Semen Colour
2.10.2 Ejaculate Volume
2.10.3 Sperm Motility
2.10.4 Sperm Concentration
2.10.5 Sperm Morphology
2.10.6 Live and Dead Sperm
2.11 Factors That Affect Cockerel Ejaculate
Volume
2.11.1 Species and Breed
2.11.2 Nutrition
2.11.3 Age, Frequency and Technique of Semen
Collection
2.11.4 Season and Temperature
2.12 Factors Affecting Cockerel Semen Quality
Post-
2.12.1 Ambient Temperature
2.12.2 Osmotic Pressure in Poultry Semen
2.12.3 Semen Plasma Concentration
2.12.4 Antimicrobial Agents
2.12.5 Cockerel Semen Ph
2.12.6 Gonadotrophic Hormones
2.12.7 Gases
2.12.8 Photoperiod
2.13 Thyme (Thymus
Vulgaris)
2.13.1 Benefits of Thyme
2.13.2 Chemical Composition of Thyme (Thymus Vulgaris)
2.14 Effect
of Crude Protein on Growth Performance and Semen
2.15 Effect of Thyme Supplements on Blood Profile
CHAPTER 3
MATERIALS AND METHODS
3.1 Experimental Site
3.2 Experimental Diets
3.3 Experimental Birds and Management
3.4 Preparation of Test Ingredients Thyme (Thymus Vulgaris) Leaf Meal
3.5 Semen Collection
3.6 Semen Evaluation
3.6.1 Macroscopic Examination
3.6.2 Microscopic Examination
3.7 Libido Assessment
3.8 Hematological Evaluation
3.9 Determination of Serum Profile
3.10 Evaluation
of Seminal Plasma Parameters
3.10.1 Total Protein (TP)
3.11 Evaluation of Growth Performance
3.12 Histopathological Study
3.13 Experimental Design and Procedure
3.14 Statistics
CHAPTER 4
RESULTS AND DISCUSSION
4.1 Effect of Feeding Different Levels of
Thyme and Dietary Protein on the Semen Characteristics of Nigerian Local Cocks
4.2 Effect of Feeding Different Levels of
Thyme and Dietary Protein on the Reaction Time of Nigerian Local Cocks
4.3 Effect of Feeding Different Levels of
Thyme and Dietary Protein on Haematological Parameters of Nigerian Local Cocks
4.4 Effect of Feeding Different Levels of
Thyme and Dietary Protein on Differential White Blood Cell Count of Nigerian
Local Cocks
4.5 Effect of Feeding Different Levels of
Thyme and Dietary Protein on Serum Biochemical Parameters of Nigerian Local
Cocks
4.6 Effect of Feeding Different Levels of
Thyme and Dietary Protein on Seminal Plasma of Nigerian Local Cocks
4.7 Effect of Feeding Different Levels of
Thyme and Dietary Protein on the Relative Organ Weights of Nigerian Local Cocks
4.8 Effect of Feeding Different Levels of
Thyme and Dietary Protein on the Weight Performance of Nigerian Local Cocks
4.9 Effect of Feeding Different Levels of
Thyme and Dietary Protein on Histology of Testes of Nigerian Local Cocks
4.10 Effect of Feeding Different Levels of Thyme
and Dietary Protein on Spermatid Density Count/ Tubule of Nigerian Local Cocks
CHAPTER 5
CONCLUSION AND RECOMMENDATIONS
5.1 Conclusion
5.2 Recommendations
References
LIST OF TABLES
Table 2.1: Chemical components of semen in the domestic
cockerel.
Table 2.2: Chemical composition of the essential oil from
leaves of thyme (Thymus vulgaris).
Table 3.1: Gross composition of the experimental diets (%
Composition).
Table 3.2: Descriptive and numerical scales for evaluation
of microscopic pattern of semen.
Table 3.3: Libido grading for experimental male animals.
Table 4.1: Effect of feeding different levels of thyme
and dietary protein on the semen colour of Nigerian local cocks.
Table 4.2: Effect of feeding different levels of thyme
and dietary protein on the semen volume of Nigerian local cocks.
Table 4.3: Effect of feeding different levels of thyme
and dietary protein on the semen pH of Nigerian local cocks.
Table 4.4: Effect of feeding different levels of thyme
and dietary protein on the semen consistency of Nigerian local cocks.
Table 4.5: Effect of feeding different levels of thyme
and dietary protein on the progressive motility of spermatozoa of Nigerian
local cocks.
Table 4.6: Effect of feeding different levels of thyme
and dietary protein on the spermatozoa live proportion of Nigerian local cocks.
Table 4.7: Effect of feeding different levels of thyme
and dietary protein on the spermatozoa concentration of Nigerian local cocks.
Table 4.8: Effect of feeding different levels of thyme
and dietary protein on the total number of spermatozoa per ejaculate of
Nigerian local cocks.
Table 4.9: Effect of feeding different levels of thyme
and dietary protein on the normal spermatozoa proportion of Nigerian local
cocks.
Table 4.10: Effect of feeding different levels of thyme and
dietary protein on the total abnormal spermatozoa of Nigerian local cocks.
Table 4.11: Effect of feeding different levels of thyme and
dietary protein on the reaction time of Nigerian local cocks.
Table 4.12: Effect of feeding different levels of thyme and
dietary protein on the haematological parameters of Nigerian local cocks.
Table 4.13: Effect of feeding different levels of thyme and
dietary protein on the differential white blood cell count of Nigerian local
cocks.
Table 4.14: Effect of feeding different levels of thyme and
dietary protein on the serum biochemical parameters of Nigerian local cocks.
Table 4.15: Effect of feeding different levels of thyme and
dietary protein on the seminal plasma of Nigerian local cocks.
Table 4.16: Effect of feeding different levels of thyme and
dietary protein on the relative organ weight of Nigerian local cocks
(Viscerosomatic index).
Table 4.17: Effect of feeding different levels of thyme and
dietary protein on the relative testicular weight of Nigerian local cocks
(Gonadosomatic index).
Table 4.18: Effect of
feeding different levels of thyme and dietary protein on the weight performance
of Nigerian local cocks.
LIST OF FIGURES
Figure 4.1: Showing the effect of feeding different levels
of thyme and dietary protein on reaction time.
Figure 4.2: Showing the
effect of feeding different levels of thyme and dietary protein on libido
score.
Figure 4.3: Matured
spermatid density
LIST OF PLATES
Plate 1: Experimental
test ingredient (Thyme)
Plate 2: Experimental Birds (Nigerian local cocks).
Plate 3: Grounded
test ingredients (Thyme)
Plate 4: Experimental
diets
Plate 5: Experimental
procedures (Semen collection).
Plate 6: Experimental procedure (Blood collection).
Plate 7: Experimental birds being weighed
Plate 8: Weighing of
testicular organs
Plate 9: Exposed
testicular organs
Plate 10: Photomicrograph of local cock testes fed with
0.0g/kg thyme and 18% CP
Plate 11: Photomicrograph of local cock testes fed with
0.0g/kg thyme and 21% CP
Plate 12: Photomicrograph of local cock testes fed with
5.0g/kg thyme and 18% CP
Plate 13: Photomicrograph of local cock testes fed with
5.0g/kg thyme and 21% CP
Plate 14: Photomicrograph of local cock testes fed with
10.0g/kg thyme and 18% CP
Plate 15: Photomicrograph of local cock testes fed with
10.0g/kg thyme and 21% CP
CHAPTER 1
INTRODUCTION
1.1 BACKGROUND OF THE STUDY
The poultry industry is one of the
fastest growing segments of the agricultural subsector in Nigeria. Rapid human
population and low protein intake are some of the major problems facing
developing countries like Nigeria. Poultry products (meat and eggs) present the
most affordable source to mitigate the problems of protein malnutrition in
Nigeria (Akinokun, 1990). The Nigerian local chicken which consists of between
80 to 90 percent of the local population has small body size, poor growth,
small egg size and poor reproductive performance (Lisowski and Bednarczyk,
2005; Hafez and Hafez, 2000). These characteristics make them undesirable stock
in a competitive economic situation (Oguike et
al., 2000). However, the local chickens hold some potentials if their
reproductive performance can be improved. Improvement in reproduction of the
Nigerian local cocks is crucial to the socioeconomic status of Nigerian rural
dwellers. Currently, majority of researchers are focusing on the use of herbs
and medicinal plants as an alternative for improving the reproductive
performance of both food and breeder animals (Xie et al., 2010; Marai et al.,
2006; Peters et al., 2004). This is
aimed at minimizing the use of certain synthetic antibiotics and hormones as a
stimulant for growth which is harmful to animals and consequently, human health
due to the accumulation of remnants of these substances in animal products
along the food chain (Castanon, 2007).
Thyme (Thymus vulgaris L) is a shrubby perennial plant that grows 15 to
30 cm high. It has narrow, pale grey/green leaves with a pungent woody aroma. A
native of the
Mediterranean, it grows best in areas where there is
plenty of sun and drainage.
Drought conditions tend to concentrate the oil,
producing a more powerful flavour.
It grows abundantly in France, Spain,
Portugal, Italy, Algeria and Morocco (Garmsir, 2014). However, thyme is readily
available in Nigeria where it is used as a spice and food flavor as well as
anti-oxidant for treatment of many diseases (Mathur et al., 2003). Thyme has also been used in animal feed and poultry
as anti-oxidants and as stimulant for growth (Dhama et al., 2014; Omeje and Marire, 2007). There is a myth that males
who eat foods well spread with thyme show high libido indicating the likelihood
of thyme having aphrodisiac properties (Zhu et
al., 2016; Rota and Herrera, 2002). Sultan et al. (2008) used thyme leaves in a study aimed at reducing the
age of puberty in female of domestic rabbits.
Poultry production is one of the surest
and fastest means of bridging the animal protein supply needs of any nation,
especially for countries like Nigeria where it has been reported that an
average individual consumes about 7.5g of animal protein as against 28g
consumed by an average Briton (Mmereole et
al., 2001). The local chickens constitute the majority of poultry types in
Nigeria, being about 106 million in population (Ajayi, 2010) with more than 80%
in the rural areas `where they contribute substantially to annual meat and egg
production.
The reproductive potential of a cock is
determined to a large extent by the quality of the semen it produces. The
importance of semen evaluation in poultry breeding, for selecting breeding
males or for routine monitoring of their reproductive performance cannot be
overemphasized. The assessment of semen quality characteristics of Nigerian
local chicken gives excellent indices of its reproductive potential and has
been reported to be a major determinant of fertility and subsequent
hatchability of eggs (Peters et al.,
2004). Several reports on semen characteristics of the domestic fowls have
indicated that breed and strain significantly affects semen quality and
quantity (Bah et al., 2001; Tuncer et al., 2006; Peters et al., 2008). Indigenous Nigerian
breeds have been reported to have many advantageous gene complexes or gene
markers that could be harnessed in the development of meat or egg-type chickens
suitable for use in the tropics (Machebe and Ezekwe, 2005). The local birds can
easily adapt to the rural environment, survive on little or no food supplement
and adjust to fluctuations in feed availability.
In a breeder flock, fertility rates are
often related to the male performance. However, their dietary management is
often inadequate as they are fed diets formulated to meet their needs
(Gonçalves et al., 2015). Obi et al. (2013) reported that nutrition is
important in pre-puberty, puberty and maturity stages of male broiler breeders.
They further observed that malnutrition or over-consumption leads to weight
loss or gain respectively at any of the three sexual stages possibly affecting
sperm production. This disruption can lead to permanent non-functional testis
and reduced reproductive performance. It was also reported by Martin and
Walkden-Brown, (1995) that circulating nutrients may directly affect the
secretion of luteinizing hormone (LH) in the pituitary or indirectly by
decreasing signals from median eminence. Although it is well known that energy
and protein are major nutrients that affect the reproductive performance of
poultry, for the Nigerian local chicken there is a paucity of information on
their nutritional requirements as it affect reproduction.
1.2 STATEMENT OF PROBLEM
It has been reported that Nigerian
local chickens which consist of between 80 – 90 percent of the local population
have small body size, poor growth, small egg size and poor reproductive
performance (Oguike et al., 2000).
However, indigenous Nigerian breeds have been reported to have many
advantageous gene complexes that could be harnessed in the development of meat
and egg type chicken suitable for use in the tropics (Machebe and Ezekwe,
2005).
It is therefore pertinent to know that
the body conformation of Nigerian local or indigenous breeds has no
disadvantageous effect on its physiological characteristics and response. There
is need to enhance the reproductive performance of the local cocks through
feeding materials that will enhance libido (sex drive) as well as sperm production.
High semen output in terms of semen volume and sperm concentration with other
physiological characteristics can be effectively determined in Nigerian local
cocks. This research is therefore designed to investigate selected substances
which have nutritional attribute that could enhance sperm production and
physiological parameters of Nigerian local cocks.
1.3 OBJECTIVES OF THE STUDY
The main objective of this study is to
determine the effect of thyme (Thymus
vulgaris) on the semen characteristics of Nigerian local cocks.
1.3.1 Specific
objectives
The specific objectives are to:
i) determine the semen characteristics and
libido of Nigerian local cocks fed diets containing thyme (Thymus vulgaris) leaf meal and dietary protein; ii) determine
the effect of feeding different levels of thyme and dietary protein on
haematology of Nigerian local cocks; iii) determine the effect of feeding
different levels of thyme and dietary protein on serum biochemical
characteristics of Nigerian local cocks; iv) determine the seminal plasma composition
of Nigerian local cocks fed diets containing different levels of thyme and
dietary protein;
v)
determine the effect of feeding different levels
of thyme and dietary protein on relative organ weights of Nigerian local cocks;
vi)
determine the weight performance of Nigerian
local cocks fed diets containing different levels of thyme and dietary protein;
and vii) determine the histopathological effect on testicular tissue of
Nigerian local cocks fed diets containing different levels of thyme and dietary
protein.
1.4 JUSTIFICATION OF THE STUDY
According to Garmsir (2014) report,
that dietary supplementation of fish oil and thyme can improve sperm quality in
miniature Caspian horse, it therefore means that there is the likelihood that
dietary supplementation of thyme can also improve sperm quality and increase
libido in breeder male Nigerian local cocks.
It is hoped that the findings from this
study will not only provide scientific support to the findings of Garmsir
(2014), (and by extrapolation if the use of graded levels of Thymus vulgaris in the formulation of
feeds for the Nigerian indigenous breeder cocks, could improve the quality of
their semen output, and other physiological characteristics for the purpose of
breeding especially as it affects crude protein content), it would also
contribute to the growing database of knowledge in animal feed formulation for
breeder cocks, assist the end users on the benefits, as well as advocate the
right proportion of Thymus vulgaris and
crude protein that will enhance the reproductive performance of breeder male
animals.
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