ABSTRACT
Four experiments were conducted to determine the physiological responses of New Zealand White rabbits to ginger rhizome powder (GRP) supplementation during pre-pubertal, pubertal and post pubertal stages of development. Firstly, GRP was analyzed to determine its proximate nutritional, amino acids, mineral and phytochemical compositions. Thereafter, it was included in commercial rabbit rations at the rate of 0 g (BT1 control), 5.0 g (BT2), 10 g (BT3) and 15 g (BT4) per kilogram of feed as supplement. In the second experiment, 72 pre-pubertal rabbits of equal sex distribution and aged 10 to 12 weeks were divided into four groups of 18 rabbits each and replicated three times in a randomized complete block design. They were fed the treatment diets for 12 weeks, while Panicum maximum and Centrosema pubescen were fed as additional fibre sources. Physiological responses were assessed using growth performance, hematology, serum biochemistry, carcass and organ characteristics. In the third experiment, 72 pubertal rabbits were divided into 4 groups of 18 each, which were again replicated three times in a completely randomized complete block design and suplemented with GRP at the same rates as the second experiment to determine GRP effects on selected male and female reproductive characteristics over a period of  10 weeks. In a fourth and final experiment, 72 post pubertal rabbits were similarlly used to determine GPR effects on growth performance, male and female reproductive and breeding characteristics, hematology, serum biochemistry over a period of 12 weeks. GRP analyses yielded mainly saponin (4.01 mg / 100g) and relatively low levels of proximate nutrients and amino acids. Predominant mineral elements were in the order of Na > K > Ca > P > Mn > Zn > Fe > Cu. At the pre-pubertal stage, the control, BT2 and BT4 recorded statistically similar final body weight (FBW), body weight gain (BWG) and feed conversion ratio (FCR) (p<0.05). The rabbits exhibited strong sexually dimorphism in their FBW and BWG values, which were significantly (p<0.05) different. Packed cell volume (PCV) and hemoglobin (Hb) values of BT2 and BT4 groups and white blood cell (WBC) and neutrophil counts of BT1 and BT4 groups were significantly influenced (p<0.05) by sexes. Serum cholesterol and triglycerides values of female BT4 group were generally statistically (p<0.05) higher than those of the males. At the pubertal stage, percentage live and dead sperm cells as well as live: dead sperm ratios were significantly (p<0.05) different in BT2, BT3 and BT4 groups. There were also significant (p<0.05) differences in % sperm motility between BT1 and BT4 groups. Control bucks had significantly (p<0.05) higher testicular weight than others. Ovarian weights were comparable (p>0.05) among the groups, with follicle stimulating hormone (FSH) value of BT4 and luteinizing hormone (LH) value of BT2, BT3 and BT4 being significantly (p<0.05) lower than those of the control. Estradiol-17ß values of BT2 and BT3 were equally significantly (p<0.05) different from those of the control and BT4 groups. Testicular histographs of supplemented groups revealed tissue degenerations. In the post – pubertal rabbit experiment, growth performance was significantly influenced (p<0.05) by GRP supplementation. Semen parameters values deteriorated with increase in GRP supplementation. Values of hematological parameters were generally within normal range. Significant sex effects (p<0.05) were however observed in PCV, WBC, lymphocyte, neutrophil counts serum cholesterol concentrations of BT3 and BT4 groups, as well as total serum protein values of BTI and BT4 and serum albumin and calcium value for BT4 rabbits. Serum 17ß – estradiol value of the BT1 does was significantly higher (p<0.05) than those in BT4 treatment group, while progesterone values increased with GRP supplementation and resulted in zero breeding in the BT3 and BT4 does. Testosterone concentration also increased with increasing GRA supplementation, with BT4 recording significantly higher values (p<0.05) than the control. The highest testicular weight was obtained in BT1 group whose values differed significantly (p<0.05) from BT3 and BT4 bucks. Histological assessment of the testes in BT2, BT3  and BT4 groups showed evidence of testicular degeneration. Overall results show that supplementation of up to 15 g / kg feed of ginger rhizome powder improved growth performance of rabbits but was associated with hormonal imbalance across sexes, reduced sperm quality and testicular degeneration in males and poor breeding performance in females. The growth improvement and contraceptive effects of ginger rhizome powder should be investigated for further exploitation of its benefits in animal production.
Keywords:Â Â Physiological, Rhizome Powder, Phytochemical Compositions
TABLE OF CONTENTÂ Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â PAGE
Title page                                                        i
Copyright                                                       iii
Certification                                                      iv
Dedication                                                       v
Acknowledgement                                                 vi
Table of Contents                                                  viii
List of Tables                                                     xv
List of Figures                                                   xviii
List of Plates                                                    xix
Abstract                                                        xx
CHAPTER ONE
1.0       Introduction                                             1
1.1       Problem statement                                         4
1.2      Objectives of the study                                      6
1.3      Justification of the study                                     6
CHAPTER TWO
2.0              Literature Review                                       7
2.1              Overview of rabbit production                              7
2.2              Constraints to rabbit production in Nigeria                     8
2.3              Blood chemistry                                      10
2.3.1           Hematological characteristics of rabbits                      10
2.3.1.1         Red blood cell                                        10
2.3.1.2         Packed cell volume                                    11
2.3.1.3         Hemoglobin concentration                               11
2.3.1.4        Red cell indices                                        12
2.3.1.5 Â Â Â Â Â Â Â White blood cell (WBC) and differential WBCÂ Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â 13
2.3.2           Serum biochemical characteristics of rabbits                   13
2.3.2.1         Serum proteins                                       18
2.3.2.2         Serum urea                                         19
2.3.2.3         Serum glucose                                       19
2.3.2.4         Serum creatinine                                      20
2.3.2.5         Serum cholesterol                                    20
2.3.2.6         Serum electrolytes                                    21
2.3.2.7         Serum liver enzymes                                  22
2.3.2.8         Serum bilirubin                                       23
2.4              Steroids and sex hormones                              23
2.4.1            Testosterone                                        24
2.4.2           Estradiol                                            24
2.5              Reproductive physiology of rabbits                         25
2.5.1           Reproductive characteristics of female rabbits                 25
2.5.1.1     Folliculogenesis                                      26
2.5.1.2         Oestrus cycle and oestrus behaviour                      27
2.5.1.3        Conception rate and gestation length                      28
2.5.1.4         Litter characteristics                                 28
2.5.2           Reproductive characteristics of male rabbits                 29
2.5.2.1        Sexual Libido                                       30
2.5.2.2        Spermatogenesis                                   30
2.5.2.3        Spermatozoa and maturation                          31
2.5.2.4         Composition of spermatozoa                           32
2.5.2.5        Semen collection                                   33
2.5.2.6         Semen handling and evaluation                        34
2.5.2.7         Mechanics of flagella motility                          37
2.5.2.8         Sperm energy metabolism                           38
2.5.2.9 Â Â Â Â Â Â Â Â Sperm glycogen synthase Kinase-3Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â 40
2.5.3.0      Spermcapacitation                                     41
2.5.3.1         Sperm acrosomal reaction                           42
2.5.3.2         Spermatozoa membrane lipids                         42
2.6               Free radicals                                     43
2.6.1            Free Radical Formation                             45
2.6.2           Types of Free Radicals                              46
2.6.3 Â Â Â Â Â Â Â Â Â Â Â Oxygen free radical [Reactive oxygen species (ROS)]Â Â Â Â Â Â Â Â 46
2.6.4           Bio-negative effects of oxygen free radicals               47
2.6.5            Bio-positive effect of free radicals                      48
2.6.6           Oxygen free radical and peroxidation of membrane lipids      49
2.7             Oxygen free radical and spermatozoa                    49
2.7.1            Free radical and sperm function                        50
2.7.2     Biological implications of lipid peroxidation products on spermatozoa  51
2.7.3           Interaction between free radicals, Leukocytes and sperm functions   52
2.8              Antioxidant                                          52
2.8.1           Mode of action of antioxidant                             53
2.8.2            Enzymatic antioxidants                                 53
2.8.3            Non-enzymatic antioxidants                              54
2.8.4            Antioxidants and spermatogenesis                         56
2.9 Â Â Â Â Â Â Â Â Â Â Â Â Â Ginger (Zingiber officinale)Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â 58
2.9.1            Scientific classification                                58
2.9.2           Botanical description                                 58
2.9.3           Nutrient and bioactive compositions of ginger               58
2.9.4            Physico – chemical properties of ginger oil                  62
2.9.5            Pharmacological properties of ginger                      62
2.9.5.1        Effect of ginger on blood lipid and glucose concentrations       64
2.9.5.2         Anti – inflammatory and analgesic activities of ginger          65
2.9.5.3        Effect of ginger on gastrointestinal tract                    66
2.9.5.4        Tissue and radio-protective effects of ginger                 67
2.9.5.5         Effect of ginger on blood pressure                        68
2.9.5.6        Anti-microbial actions of ginger                           68
2.9.5.7        Antioxidant actions of ginger                             69
2.9.5.8        Effect of ginger on blood clotting                         70
2.9.5.9         Hormonal activity of ginger                             71
2.9.5.10      Anti-diabetic activity of ginger                           71
2.9.5.11       Effects of ginger on semen quality                        71
2.9.5.12      Toxicological properties of ginger                          72
CHAPTER THREE
3.0              Materials and Methods                               74
3.1              Study location                                      74
3.2               Overview of the study                               75
3.3 Â Â Â Â Â Â Â Â Â Â EXPERIMENT 1 : EVALUATION OF PHYTOCHEMICAL AND NUTRITIONAL COMPOSITIONS OFÂ Â Â Â Â Â Â Â Â 76 GINGER RHIZOME POWDER
3.3.1           Preparation of ginger rhizome powder                         76
3.3.2            Phytochemical determination                               76
3.3.3            Proximate biochemical determination                        81
3.3.4            Mineral contents determination                             84
3.3.5           Amino acid determination                                 85
3.3.6            Data analysis                                         86
3.4              EXPERIMENT 2 : EFFECTS OF GINGER RHIZOME POWDER ON BLOOD CHEMISTRY       87 AND PERFORMANCE CHARACTERISTICS OF PRE – PUBERTAL RABBITS
3.4.1            Experimental animals                           87
3.4.2            Experimental diets and analysis                    87
3.4.3            Experimental design                             87
3.4.4           Growth performance determination                   89
3.4.5           Blood collection                               89
3.4.5.1         Hematological assay                           90
3.4.5.2         Serum biochemical assay                        92
3.4.6           Internal organ weight determination                 96
3.4.7            Data analysis                                  97
         3.5               EXPERIMENT 3 : EFFECTS OF GINGER RHIZOME POWDER ON REPRODUCTIVE CHARACTERISTICS OF PUBERTAL RABBITS                                    98       Â
3.5.1            Experimental animals                          98
3.5.2           Experimental diets and design                     98
3.5.3            Reproductive performance                         98
3.5.4            Sex hormonal analyses                           98
3.5.5            Sexual libido                                   101
3.5.6           Semen collection and evaluation                      102
3.5.7           Testicular and ovarian biometric measurements           104
3.5.8           Testicular and ovarian histological examinations          104
3.5.9            Data analysis                                  104
3.6            Experiment 4 : Effects of Ginger Rhizome Powder on Physiological Parameters of Post – Â
PUBERTAL RABBITS
3.6.1            Experimental animals                              106
3.6.2           Experimental diets, design, libido and semen              106
3.6.3           Mating of experimental rabbit does                     106
3.6.4            Blood collection and analysis                        107
3.64.1          Hematological assay                              107
3.6.4.2         Serum biochemical analysis                       107
3.6.5           Sex hormone analysis                           107
3.6.6           Testicular and ovarian biometric measurements          108
3.6.7           Testicular and ovarian histological examination           108
3.6.8            Data analysis                                   108
    Â
CHAPTER FOUR
4.0 Â Â Â Â Â Â Â Â Â Â RESULTS AND DISCUSSION Â Â Â Â Â RESULTS
4.1 Â Â Â Â Â Â Â Â Â Â Â EXPERIMENT 1: EVALUATION OF PHYTOCHEMICAL AND NUTRITIONAL COMPOSITIONS OF GINGER RHIZOME POWDER
4.1.1         Phytochemical compositions of ginger rhizome powder           109
4.1.2         Proximate compositions of ginger rhizome powder              109
4.1.3         Amino acid compositions of ginger rhizome powder             109
4.1.4         Mineral compositions of ginger rhizome powder              114
4.2    EXPERIMENT 2: EFFECTS OF GINGER RHIZOME POWDER ON BLOOD CHEMISTRY AND Performance Characteristics of Pre – pubertal Rabbits
4.2.1a       Performance characteristics                            116
4.2.1b       Influence of sex on performance characteristics              116
4.2.2a       Hematological characteristics                            120
4.2.2b       Influence of sex on hematological characteristics              120
4.2.3a       White blood cell (WBC) and differential WBCcounts            120
4.2.3a    Influence of sex on WBC and differential WBC counts
4.2.4a       Serum biochemical characteristics                        124
4.2.4b       Influence of sex on serum biochemical characteristics           124
4.2.5a       Serum lipid profiles                                   128
4.2.5b       Influence of sex on serum lipid profiles                     128
4.2.6a       Serum electrolyte characteristics                          128
4.2.6b       Influence of sex on serum electrolyte characteristics           132
4.2.7a       Serum liver enzyme and bilirubin characteristics               132
4.2.7b       Influence of sex on liver enzyme and bilirubin values            132
4.2.8a       Internal organ weight characteristics                       136
4.2.8b       Influence of sex on Internal organ weight characteristics        136
4.3Â Â Â EXPERIMENT 3 : EFFECTS OF GINGER RHIZOME POWDERÂ ON REPRODUCTIVE CHARACTERISTICS OF PUBERTAL RABBITS
4.3.1         Semen quality characteristics                           139
4.3.2         Female sex hormonal profiles                           141
4.3.3         Male sex hormonal profiles                             141
4.3.4         Testicular morphometry and histological characteristics         141
4.3.5         Ovarian morphometry and histological characteristics          146
4.4 EXPERIMENT 4 : EFFECTS OF GINGER RHIZOME POWDER ON PHYSIOLOGICAL PARAMETERS OF  POST – PUBERTAL RABBITS
4.4.1a       Performance characteristics                              151
4.4.1b       Influence of sex on performance characteristics                151
4.4.2         Semen quality characteristics                             151
4.4.3         Breeding characteristics                                 155
4.4.4a       Hematological characteristics                             155
4.4.4b       Influence of sex on hematological characteristics               158
4.4.5a       White blood cell (WBC) count and differential WBC counts        158
4.4.5b       Influence of sex WBC count and differential WBC              162
4.4.6a       Serum biochemical characteristics                         162
4.4.6b       Influence of sex on serum biochemical characteristics           162
4.4.7a       Serum electrolyte characteristics                         165
4.4.7b       Influence of sex on serum electrolyte characteristics            165
4.4.8a       Serum liver enzyme and bilirubin characteristics               165
4.4.8b       Influence of sex on enzyme and bilirubin values               169
4.4.9         Female sex hormonal profiles                            169
4.5.0         Male sex hormonal profiles                              169
4.5.1         Testis morphometry and histological characteristics             169
4.5.2         Ovarian morphometry and histological characteristics          177
4.6.0 Â Â Â Â Â Â Â DISCUSSION
4.6.1       Phytochemical compositions of ginger rhizome powder        180
4.6.2        Proximate compositions of ginger rhizome powder              182
4.6.3        Amino acid compositions of ginger rhizome powder              185
4.6.4        Mineral compositions of ginger rhizome powder               187
4.6.5        Performance characteristics of the pre – pubertal rabbits             190
4.6.6        Hematological characteristics of the pre – pubertal rabbits          192
4.6.7        Serum biochemical characteristics of pre – pubertal rabbits          195
4.6.8        Internal organ weight characteristics of pre-pubertal rabbits          202
4.6.9        Semen quality of pubertal rabbits                           203
4.7.0        Sex hormone concentration in pubertal rabbits                  207
4.7.1        Testicular morphometry of pubertal rabbits                   211
4.7.2        Ovarian morphometry of pubertal rabbits                     213
4.7.3        Performance characteristics of the post – pubertal rabbits          214
4.7.4        Semen quality characteristics of post – pubertal rabbit bucks      215
4.7.5        Breeding characteristics of post – pubertal rabbit bucks          218
4.7.6        Hematological characteristics of post – pubertal rabbits           219
4.7.7        Serum biochemical characteristics of post – pubertal rabbits        222
4.7.8        Sex hormone concentration in post pubertal rabbits              228
4.7.9        Testicular morphometry of post – pubertal rabbits                231
4.8.0        Ovarian morphometry of post – pubertal rabbits                 233
          Â
CHAPTER FIVE
5.0           Conclusion and Recommendation                     241
5.1           Conclusion                                     241
5.2           Recommendation                                 242
References                                             244
          Â
CHAPTER ONE
1.0 INTRODUCTION
The potentials of micro livestock such as rabbit, to meet the short fall in animal protein supply in Nigeria cannot be over emphasized. Rabbit production represents an important segment of the animal food industry throughout the world (Ogundele and Apata, 2006). According to Aduku and Olukosi (1990) rabbit production has enormous benefits which include high adaptability, easy management, high growth rate, high prolificacy and fecundity among others. In spite of these advantages, rabbit production in Nigeria has not attained its desired potential as a cheap animal protein source (Ozor and Madukwe, 2001; Oseni et al., 2008). Â
This has been blamed on numerous constraints such as industrial (poor adoption of improved rabbit technologies and lack of basic facilities), nutritional (poor quality of conventional rabbit forages) and anti – nutritional factors, poor breeding stock, increased embryo mortality and low quality of semen (Okab, 2007; Oseni et al., 2008). Among these constraints, reproductive inefficiency and poor nutrition regimens remain the most prominent in small holder rabbit production in Nigeria (Marai et al., 1995; Marai et al., 2001). In view of these production constraints, several attempts had been made to enhance the physiological well – being and reproductive traits of livestock in general and rabbits in particular (Herbert et al., 2002; Ogbuewu et al., 2009a; Obikaonu et al., 2011).
Several authors have reported significant improvements in growth performance and carcass quality of animals fed herb – based diets (Jang et al., 2009; Alimon, 2009). Herbert (2001) reported the potential feeding value of dried Gliricidia sepium and Leucaena leucocephala leaf meals on growth performance of rabbits in the humid tropical environment of southeastern Nigeria. Other studies have also highlighted some of the potentials of indigenous tropical browse plants of southeastern Nigeria used in livestock feeding (Jokthan et al., 2003; Iheukwumere et al., 2005; Nworgu and Fasogbon, 2007). The potential of leaf meals of tropical browse plants and forage trees such as Ficus thonningii and Azadirachta indica in livestock feeding has also been demonstrated (Sokunbi and Egbunike, 2000a,b Esonu et al., 2006; Ogbuewu, 2008).
Phytochemical compositions of commonly used forages in small holder rabbit production in Nigeria were reported by Esonu et al. (2001), Onwuliri and Umezurumba (2003) and Soetan (2008). Some of the phytochemical substances in tropical browse plants and shrubs used in animal production include alkaloids, terpenoids, tannins, flavonoids and saponins among others (Osagie, 1998; Onwuliri and Umezurumba, 2003). These bioactive principles have found wide applications in the fields of medicine and pharmacy as pharmacologically active agents (Soetan, 2008; Ogbuewu et al., 2011) and may include antimicrobial, antiinflammatory, antioxidant, antidiabetic and anthelmintic activities (Soetan, 2008). However, the extensive use of forages in rabbit production may be limited by the presence of antinutritional factors in some tropical plants (Herbert, 2001; Sokunbi and Egbunike, 2000a).
Several studies also showed that plant bioactive principles elicit both stimulatory and inhibitory actions on the reproductive functions of rabbits (Ogbuewu et al., 2009a; Uboh et al., 2010; Oguike and Archbong, 2011). For example, the potential benefits of soy meal, Xylopia aethiopica and Garcinia kola bioactive principles in sperm production and functions in rabbit bucks have been established (Iwuji 2010; Oyeyemi and Okediran, 2007; Oguike and Archbong, 2011). Similarly, sperm production and functions have been enhanced in rabbit bucks using a fertility drug; Clomiphene citrate (Herbert et al. , 2002;, Ndubueze, 2002), while the age at sexual maturity was observed by Chibundu (2005) to be shortened in rabbit bucks administered estradiol. Icariin, a flavonoid isolated from the plant, Herba epimedii has also been used to ameriorate erectile dysfunction, increase testicular weight and the testosterone concentration in male rabbits (Uboh et al., 2010).
Sex hormones such as testosterone and estradiol are known to regulate the reproductive functions and characteristics in both males and females (Granner, 2000; Chatterjea and Shinde, 2002), while environmental conditions, such as poor nutrition and high environmental temperature influence the hormonal profile of rabbits (Meshreky et al., 2003; Meshreky et al., 2007). Administration of Psidium guajava (Uboh et al., 2010), Cnidoscolous aconitifolius (Yakubu et al., 2008) and Zingiber officinale (Arash et al., 2009) extracts have been shown to enhance sex hormone synthesis and secretions in animals.
Although, the physiological and reproductive traits of rabbits have been improved in this part of the world using synthetic fertility drugs (Herbert et al., 2000 and 2002), this technology has not received the desired attention from resource poor rabbit farmers due to high level of technical expertise needed in its preparation and administration. Similar constraints, have limited the adoption of research results, especially by resource poor small holder livestock farmers that dominate rabbit farming in Nigeria. In view of these adoption constraints, there is the need to research the potentials of plants with known reproductive effects such as ginger, bitter kola and onions among others (Adedeji et al., 2006; Ogbuewu et al., 2009a).
Specifically, ginger is a shrub used widely in herbal medicines and as a spice all over the world (Bartley and Jacobs, 2000). It is a slender, perennial rhizomatous herb. According to Warrier et al. (1995), the pseudostem formed the leaf sheath and bears about 8 – 12 distichous leaves. Leaves are linear and glabrous and the flowers are yellowish green, arranged in oblong, cylindric spikes and ensheathed in a few scarious bracts. The rhizome is always whitish to yellowish brown in colour, irregularly branched, somewhat annulated and laterally flattened. The growing tips are covered by a few scales, while the surface of the rhizome is smooth and if broken, a few fibrous elements of the vascular bundles project out from the cut ends.
Ginger and its products have attracted widespread interest in nutrition research, biology and medicine because of their demonstrated beneficial antioxidant effects (Soetan, 2008; Ogbuewu et al., 2010a; Saeid et al., 2011). Antioxidants enhance the physiological functions due to their inherent ability to protect body cells and tissues from the ravages of oxygen (Ogbuewu et al., 2010b). Studies by Herrmann (1994), Sekiwa et al., (2000) and Zancan et al. (2002) have shown that the major ginger bioactive substances, such as zingerone, gingerdiol, zingibrene, gingerol and shogaol possess antioxidant ability.
Thus, ginger is a tropical plant that has strong antioxidant property and has dominative protective effects on DNA damage induced by oxygen free radicals (Grzanna et al., 2005; Ghada et al., 2009; Ogbuewu et al., 2010a). For example, the spermatogenic potentials of ginger in rats and broilers have been attributed to its antioxidant property (Arash et al., 2009; Tamara et al., 2009; Ogbuewu et al., 2010b). The reported increase in testicular weight of males fed ginger rhizome powder based diets is a pointer that such ginger products promote growth and development of testicular matrix (Arash et al., 2009; Saeid et al., 2011). The observed increase in semen quality characteristics of animals fed ginger powder based diets was attributed in part to the ability of ginger bioactive compounds to protect the lipid matrix of spermatozoa against free radical attack (Arash et al., 2009; Saeid et al., 2011). The main pharmacological actions of ginger and its compounds include immuno-modulatory, anti-tumorigenic, anti-inflammatory, anti-apoptotic, antihyperglycemic, anti- lipidemic and anti-emetic has been reported (Ghada et al., 2009; Tamara et al., 2009). Ginger powder has also been reported to improve blood testosterone and testicular size in male rats and cocks (Arash et al., 2009; Saeid et al., 2011).
1.1 PROBLEM STATEMENT
The Nigerian livestock industry has been faced with numerous challenges, such as high cost of conventional feed ingredients, diseases, poor quality forages as well as poor production environment. The association of these factors with reduced fertility rate in farm animals is increasingly a source of concern to livestock producers in Nigeria. The use of synthetic fertility preparations and plant bioactive principles has been found to be effective in solving this problem in developed countries. In Nigeria, few studies have been conducted to enhance physiological parameters, especially reproductive traits in farm animals using commercial fertility preparations such as Clomiphene citrate, testosterone, estradiol and pergonal (Herbert et al., 2002; Iheukwumere, 2004; Chibundu, 2005). However, the variations in research findings, coupled with the high level of expertise needed in the preparation and administration of these drugs has limited their adoption, especially by the small holder livestock farmers.
In view of these adoption constraints, there is the need to enhance overall physiological well being and in particular the reproductive performance of livestock such as rabbit using cheap and readily available plants with antioxidant ability such as ginger, bitter kola and soy bean in the diet (Herbert et al., 2005; Adedeji et al., 2006; Ogbuewu et al., 2009b). Antioxidants are capable of disposing, scavenging and suppressing the formation of reactive oxygen species with the ultimate goal of protecting cells and tissues from the ravages of free radicals (Ogbuewu et al., 2010d). Generally, plants exhibiting antioxidant activity have been established to enhance physiological parameters, especially the reproductive traits of small laboratory animal models (Arash et al., 2009; Tamara et al., 2009; Ogbuewu et al., 2010b).
Studies have documented the antioxidant and other physiological benefits of ginger (Zancan et al., 2002; Arash, et al., 2009; Saeid et al., 2011). Most of these studies have been carried out using small laboratory animal models thus yielding data that are not directly linked to animal production. Thus, most of the information generated even though good is of no direct use to agricultural extension officers and resource poor small holder farmers. Therefore, there is the need to situate plant antioxidant research within the context of tropical animal production realities in order to generate adoptable and utilizable information.
Again, the routing of research findings through technology development processes has continued to place important research results out of the reach of target farmers due to added cost and poor infrastructural development. For example, the need to extract the active principles from ginger may make its application impracticable for resource poor farmers. Thus, the production of ginger in the form of rhizome powder instead of extract is basically adopted to extend the shelf life of the product and also to make it easily adoptable by resource poor farmers. There is however, no available information on the physiological conditions including reproductive performance of livestock such as rabbits fed ginger rhizome powder, especially in Nigeria. Therefore, the general research question to ask is, will the feeding of ginger rhizome powder supplemented diets affect physiological functions in rabbits? The specific questions include;
- What are the phytochemical and nutritional characteristics of the locally available ginger rhizome?
- What are the responses of rabbits to diets supplemented with different levels of ginger rhizome powder?
- Will ginger rhizome powder affect reproductive performance of the rabbit?
- Wii ginger rhizome powder affect hematological and serum biochemical characteristics of the rabbits?
1.2 Â Â Â OBJECTIVES OF STUDY
The general objective of this study is to evaluate the physiological responses of rabbits to ginger rhizome powder supplementation. The specific objectives include:
- To determine the phytochemical and nutritional compositions of ginger rhizome powder.
- To determine the performance of pre – pubertal and post – pubertal rabbits fed diets supplemented with different levels of ginger rhizome powder.
- To determine the reproductive characteristics of pubertal and post – pubertal rabbits fed diets supplemented with different levels of ginger rhizome powder.
- To determine the toxicological effects of ginger rhizome powder based diets on pre – pubertal, pubertal and post pubertal rabbits using: Hematological parameters, serum biochemical indicators and liver function.
1.3 JUSTIFICATION OFÂ THE STUDY
The rabbit offers an alternative to other meat producing species for the improvement of man‟s protein supply. This is due to its high productivity and the fact that rabbit need not be in competition with humans for food. Inadequate information and advocacy on them seem to make this valuable protein source underutilized in animal husbandry in Nigeria. This task was also made more difficult by the previous neglect of the rabbit in animal meat research. Thus, rabbit production in Nigeria is in need of urgent research studies that will improve its acceptability as a good source of animal protein in the society (Ozor and Madukwe, 2001; Oseni et al., 2008). There is also the need for researched solutions to the rabbit farmer‟s plight in other to improve production performance. There is also no end to the need for recent advances in scientific information that will increase the wealth of knowledge available to researchers with interest in rabbitry science.
STUDIES ON THE PHYSIOLOGICAL RESPONSES OF RABBITS TO GINGERÂ (ZINGIBER OFFICINALEROSCOE) RHIZOME POWDER
