ABSTRACT
The aim of the study was to evaluate the ameliorative effects of sodium bi-carbonate buffer, vitamin C and Baobab fruit pulp meal (BFPM) on growth and reproductive performance of rabbits under tropical environment. Four experiments were conducted. In Experiment 1, a total of thirty (30) weaned rabbits were used. The rabbits were allotted into the treatment groups with six (6) rabbits per treatment in a completely randomized design. Rabbits in the first group (T1) were the control, animals in the treatment 2 and treatment 3 (T2) and (T3) were fed with diets as in the controls and given potassium bicarbonate (KHCO3) and sodium bicarbonate (NaHCO3) buffer respectively. Rabbits in treatment four (T4) were fed diet containing synthetic vitamin C and the fifth group (T5) was fed diet containing BFPM. Rabbits were given access to feed and water ad libitum. All recommended managerial practices were dully observed. Microclimate parameters of ambient temperature (AT) and relative humidity (RH) of the rabbitry were taken daily from February through June. The values were used to calculate temperature-humidity index (THI). Parameters monitored and measured on weekly basis included weight gain, feed intake and thermoregulatory parameters such as respiratory rate (RR), heart rate (HR), rectal temperature (RT) and ear temperature (ET). Blood samples (5 ml) were collected from the ear vein at 10.00 h from four animals chosen randomly from each group of rabbits respectively before, and at the end of the experiment and serum metabolite and thyroxine hormone levels were evaluated. In experiment two, a total of 50 adult rabbits were used comprising 25 males and 25 females. The rabbits were randomly allotted into five experimental treatment groups, with ten (10) rabbits per treatment in a completely randomized design. Rabbits were arranged in treatment groups as stated above. Parameters monitored were: thermoregulatory parameters, serum metabolites, thyrosine, testosterone and progesterone hormonal assay, semen quality characteristic, sperm morphology, epididymal and gonadal sperm reserve and reproductive performance of the female rabbits. In experiment 3, a total of thirty (30) weaned rabbits were used. The rabbits were randomly allotted into five experimental treatment groups, with six (6) rabbits per treatment in a completely randomize design. The animals were fed diets containing graded levels [0.0% (Control), 2.5%, 3.5%, 4.5% and 5.5%] of BFPM. Parameters monitored were the same as in experiment one. In experiment four, 50 adult rabbits were used, comprising 25 males and 25 females. The rabbits were randomly allotted into five experimental treatment groups, with ten (10) rabbits per treatment in a completely randomized design. Rabbits were arranged in treatment groups as in experiment three and parameters evaluated were the same as in experiment two. It was found that the THI values of year A and B were similar. THI of March to May showed that environmental conditions were stressful in these months to the animals. Vitamin C and BFPM significantly (P<0.05) reduced thermoregulatory parameters and enhanced feed intake compared to the treatments buffers. BFPM significantly (P<0.05) increased hormonal concentrations, semen quality of bucks and reproductive performance of does compared to other treatments. When graded levels of BFPM were used, it was found that the treatments with 4.5% and 5.5% significantly (P<0.05) reduced thermoregulatory parameters and enhanced feed intake compared to other treatments. While 2.5% and 3.5%BFPM, increased weight gain and final weight of growing rabbits, the treatments with 3.5 – 5.5% BFPM significantly (P<0.05) increased hormonal levels, semen quality of the rabbits and reproductive performance of does. It was concluded that BFPM is more effective in ameliorating heat stress in rabbit production and reproduction and can be used up to 5.5% inclusion level.
TABLE OF CONTENTS
Cover Page – – – – – – – – – — – – – – – – – – – – – – – – – – – – – – – – – – – – – – – – – – – – – – – – – – – – – – – – i Title Page – – – – – – – – – – – – – – – – – – – – – – – – – – – – – – – – – – – – – – – – – – – – – – – – – – – – – – – – – – ii Declaration – – – – – – – – – – – – – – – – – – – – – – – – – – – – – – – – – – – – – – – – – – – – – – – – – – – – – – – – -iii Certification – – – – – – – – – – – – – – – – – – – – – – – – – – – – – – – – – – – – – – – – – – – – – – – – – – – – – – – – iv Dedication – – – – – – – – – – – – – – – – – – – – – – – – – – – – – – – – – – – – – – – – – – – – – – – – – – – – – – – – – -v Acknowledgment – – – – – – – – – – – – – – – – – – – – – – – – – – – – – – – – – – – – – – – – – – – – – – – – – – – – -vi Table of Contents – – – – – – – – – – – – – – – – – – – – – – – – – – – – – – – – – – – – – – – – – – – – – – – – – – – -viii List of Tables – – – – – – – – – – – – – – – – – – – – – – – – – – – – – – – – – – – – – – – – – – – – – – – – – – – – – – -xvi List of Figures – – – – – – – – – – – – – – – – – – – – – – – – – – – – – – – – – – – – – – – – – – – – – – – – – – – – – xvii List of Abbreviations – – – – – – – – – – – – – – – – – – – – – – – – – – – – – – – – – – – – – – – – – – – – – – — – xix Abstract – – – – – – – – – – – – – – – – – – – – – – – – – – – – – – – – – – – – – – – – – – – – – – – – – – – – – – – – – – xx CHAPTER ONE
1.0 INTRODUCTION – – – – – – – – – – – – – – – – – – – – – – – – – – – – – – – – – – – – – – – – – – – – – – – – – -1
1.1 Hypothesis – – – – – – – – – – – — – – – – – – – – – – – – – – – – – – – – – – – – – – – – – – – – – – – — – 2
1.2 Objectives of the Study – – – – – – – – – – – – – – – – – – – – – – – – – – – – – – – – – – – – – – – – – -2
CHAPTER TWO 2.0 REVIEW OF LITERATURE – – – – – – – – – – – – – – – – – – – – – – – – – – – – – – – – – – – – – – – – – –3 2.1 General Aspect of Reproduction in Rabbits – – – – – – – – – – – – – – – – – – – – – – – – – – – – – – – – – 3 2.1.1 The male – – – – – – – – – – – – – – – – – – – – – – – – – – – – – – – – – – – – – – – – – – – – – – – – – – – – 3 2.1.1.1 Gonad development and puberty – – – – – – – – – – – – – – – – – – – – – – – – – – – – – -3 2.1.1.2 Sperm production – – – – – – – – – – – – – – – – – – – – – – – – – – – – – – – – – – – – – – – – – – – – – 4
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2.1.2 The female – – – – – – – – – – – – – – – – – – – – – – – – – – – – – – – – – – – – – – – – – – 4 2.1.2.1Gonad development, puberty and sexual maturity – – – – – – – – – – – – – – – – – – – – – -4 2.1.2.2 The Oestrus Cycle – – – – – – – – – – – – – – – – – – – – – – – – – – – – – – – – – – – – – – – – -5 2.1.2.3 Ovulation – – – – – – – – – – – – – – – – – – – – – – – – – – – – – – – – – – – – – – – – – – – – – -7 2.1.2.4 Fertilization, Gestation and Kindling – – – – – – – – – – – – – – – – – – – – – – – – – – – – – – – – 7 2.2 Reproductive Endocrinology in Rabbits – – – – – – – – – – – – – – – – – – – – – – – – – – – – – – – – – 9 2.3 Rabbit Reproduction and Environment – – – – – – – – – – – – – – – – – – – – – – – – – – – – – – -12 2.3.1 Season – – – – – – – – – – – – – – – – – – – – – – – – – – – – – – – – – – – – – – – – – – – – – – – – – – 12 2.3.2 Lighting – – – – – – – – – – – – – – – – – – – – – – – – – – – – – – – – – – – – – – – – – – – – – – – – – – -13 2.3.3 Temperature – – – – – – – – – – – – – – – – – – – – – – – – – – – – – – – – – – – – – – – – – – – – – – – – – 14 2.4 Causes and Symptoms of Heat stress in Rabbits – – – – – – – – – – – – – – – – – – – – – – – – – – -15 2.4.1 Effects of heat stress on growth performance – – – – – – – – – – – – – – – – – – – – – – – – -16 2.4.2 Effects of heat stress on thermoregulatory parameters – – – – – – – – – – – – – – – – – – – – 17 2.4.3 Effects of heat stress on reproductive performance – – – – – – – – – – – – – – – – – – – 18 2.4.3.1 Semen quality – – – – – – – – – – – – – – – – – – – – – – – – – – – – – – – – – – – – – – – – – – – – – – -18 2.4.3.2 Conception rate and Liter size – – – – – – – – – – – – – – – – – – – – – – – – – – – – – – – – – – – -19 2.4.4 Effects of heat stress on hormonal levels and serum metabolite- – – – – – – – – – – – – – 20 2.5 Methods of Alleviating or Ameliorating Heat Stress in Rabbits – – – – – – – – – – – – – – 21 2.5.1 Physical and Mechanical Techniques – – – – – – – – – – – – – – – – – – – – – – – – – – – – – – – – -21 2.6 The use of additives and supplements in alleviating heat stress – – – – – – – – – – – – – – – -22 2.6.1 Role of buffers in ameliorating heat stress – – – – – – – – – – – – – – – – – – – – – – – – – – – 22 2.6.2 Role of Vitamin C in ameliorating heat stress in livestock – – – – – – – – – – – – – – – – – – 23 2.6.3 Baobab and it role in ameliorating heat stress in livestock – – – – – – – – – – – – – – – – – – – – 24
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CHAPTER THREE 3.0 MATERIALS AND METHODS- – – – – – – – – – – – – – – – – – – – – – – – – – – – – – — – – – – – – – -29 3.1 Experimental Site – – – – – – – – – – – – – – – – – – – – – – – – – – – – – – – – – – – – — – – – – – – – – – – – 29 3.2 Preparation of Buffer- – – – – – – – – – – – – – – – – – – – – – – – – – – – – – — – – – – – – – – – – – – – – – -29 3.3. Experiment 1 Effect of Bicarbonate Buffer, Vitamins C and Baobab on the Growth Performance of Weaned Rabbit Reared under Hot Tropical Condition – – – – – – – – – – – – – – – – -29 3.3.1 Experimental Animals and Diet- – – – – – – – – – – – – – – – – – – – – – – – – – – – – – — – – – – – – – 29 3.3. 2 Data Collection- – – – – – – – – – – – – – – – – – – – – – – – – – – – – – — – – – – – – – – – – – – – – – – – -30 3.3.2.1 Meteorological Data of Rabbit Microclimate- – – – – – – – – – – – – – – – – – – – – – – – – – – – – 30 3.3.2.2 Growth Performance Parameters- – – – – – – – – – – – – – – – – – – – – – – – – – – – – – — – – – – – 31 3.3.2.3 Measurement of Thermoregulatory Parameters – – – – – – – – – – – – – – – – – – – – – – – – – – – 32 3.3.2.4 Serum Metabolite- – – – – – – – – – – – – – – – – – – – – – – – – – – – – – — – – – – – – – – – – – – – – – 31 3.3.2.5 Determination of Thyroxine (T4) Concentration- – – – – – – – – – – – – – – – – – – – – – – – – – – 32 3.4 Experiment 2: Effects of Bi-Carbonate Buffer, Vitamins C and Baobab on the Reproductive Performance of Rabbit Reared under Hot Tropical Condition- – – – – – – – – – – – – -32 3.4.1 Experimental Animals and Diets- – – – – – – – – – – – – – – – – – – – – – – – – – – – – – — – – – – – – -32 3.4. 2 Data Collection- – – – – – – – – – – – – – – – – – – – – – – – – – – – – – — – – – – – – – – – – – – – – – – – -32 3.4.3 Thermoregulatory Parameters – – – – – – – – – – – – – – – – – – – – – – – – – – – – – – — – – – – – – – – 32 3.4.4 Serum Metabolits- – – – – – – – – – – – – – – – – – – – – – — – – – – – – – – – – – – – – – – – – – – – — – – -33 3.4.5 Thyroxine and testosterone hormonal assay- – – – – – – – – – – – – – – – – – – – – – – – – – – – – – – 33 3.4.6. Semen quality evaluation- – – – – – – – – – – – – – – – – – – – – – – – – – – – – – — – – – – – – – – – – – 33 3.4.7 Evaluation of Epididymal and Gonadal Sperm Reserves- – – – – – – – – – – – – – – – – – – – – – -33 3.4.8 Reproductive Performance of Rabbit Does- – – – – – – – – – – – – – – – – – – – – – – – – – – – – – – – 34 3.4.9 Hormonal Assay- – – – – – – – – – – – – – – – – – – – – – – – – – – – – – — – – – – – – – – – – – – – – – – – -35
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3.5 Experiment 3: Effect of Supplementing Graded levels of Baobab Fruit Pulp Meal (BFPM) on Growth Performance of Rabbit Reared under Tropical Condition- – – – – – – – – – – – – – – – – – – – -35 3.5.1 Experimental Animals and Diets- – – – – – – – – – – – – – – – – – – – – – – – – – – – – – — – – – – – – -35 3.5.2 Parameters to be monitored- – – – – – – – – – – – – – – – – – – – – – – – – – – – – – — – – – – – – – – – – 35 3.6 Experiment 4: Effect of Supplementing Graded levels of Baobab Fruit Pulp Meal (BFPM) on Reproductive Performance of Rabbit Reared under Tropical Condition- – – – – – – – – – – – – – – – -36 3.6.1 Experimental Animals and Diets- – – – – – – – – – – – – – – – – – – – – – – – – – – – – – — – – – – – – -36 3.6. 2 Parameters to be monitored- – – – – – – – – – – – – – – – – – – – – – – – – – – – – – — – – – – – – – – – -36 3.7. Statistical Analysis- – – – – – – – – – – – – – – – – – – – – – – – – – – – – – — – – – – – – – – – – – – – – – – -36 CHAPTER FOUR 4.0 RESULTS – – – – – – – – – – – – – – – – – – – – – – – – – – – – – – – – – – – – – – — – – – – – – – – – – – – – – 37 Experiment 1: 4.1 Effect of Buffer, Vitamin C and BFPM on Performance of Growing Rabbits- – – – – – – – – – 37 4.1.01 Monthly Temperature Humidity Index for Year 1- – – – – – – – – – – – – – – – – – – – – – – – – – 37 4.1.02 Thermoregulatory Response of Growing Rabbit- – – – – – – – – – – – – – – – – – – – – – – – – – – -37 4.1.03 Growth Performance of Growing Rabbits- – – – – – – – – – – – – – – – – – – – – – – – – – – – – – — 39 4.1.04 Serum Metabolite of Growing Rabbits- – – – – – – – – – – – – – – – – – – – – – – – – – – – – – — – -41 4.1.05 Thyroxine Levels in Growing Rabbits- – – – – – – – – – – – – – – – – – – – – – – – – – – – – – — – – 41 Experiment Two: 4.2 Effect of Buffer, Vitamin C and Baobab Fruit Pulp Meal on Reproductive Performance of Adult Rabbits – – – — – – – – — – – – – — – – – – – — – – – – — – – — – – – – – – — – – – — – – – – – – – – – – – 44 4.2.01 Thermoregulatory Responses of Adult male Rabbits – – – – – – – – – – – – – – – – – – – – – – – – 44 4.2.02 Serum Metabolites of Adult Rabbit Bucks – – – – – – – – – – – – – – – – – – – – – – – – – – – – – — 44 4.2.03 Thyroxine Levels in Adult Rabbit Bucks – – – – – – – – – – – – – – – – – – – – – – – – – – – – – – — 47
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4.2.04 Testosterone Levels in Adult Rabbit Bucks- – – – – – – – – – – – – – – – – – – – – – – – – – – – – – -47 4.2.05 Semen Quality Characteristics of Adult Bucks – – – – – – – – – – – – – – – – – – – – – – – – – – – – 47 4.2.06 Sperm Morphology of Adult Rabbit Bucks – – – – – – – – – – – – – – – – – – – – – – – – – – – – – – -50 4.2.07 Gonadal Morphometry of Adult Rabbit Bucks- – – – – – – – – – – – – – – – – – – – – – – – – – – – -50 4.2.08 Epididymis Morphometry of Adult Rabbit Bucks – – – – – – – – – – – – – – – – – – – – – – – – – – 52 4.2.09 Gonadal and Epididymis Sperm Reserves of Adult Rabbit Bucks – – – – – – – – – – – – – – – 52 4.2.10 Serum Metabolite of Adult Rabbit Does – – – – – – – – – – – – – – – – – – – – – – – – – – – – — – – 56 4.2.11 Thyroxine Levels in Adult Rabbit Does – – – – – – – – – – – – – – – – – – – – – – – – – – – – – – – – -58 4.2.12 Progesterone Levels in Adult Rabbit Does – – – – – – – – – – – – – – – – – – – – – – – – – – – – – – -58 4.2.13 Reproductive Performance of Adult Does – – – – – – – – – – – – – – – – – – – – – – – – – – – – – – –60 Experiment 3: 4.3 Effect of Graded Levels of BFPM on Performance of Growing Rabbits – – – – – – – – – – – – – 62 4.3.01 Monthly Temperature Humidity Index for Year 1- – – – – – – – – – – – – – – – – – – – – – – – – – 62 4.3.02 Thermoregulatory Response of Growing Rabbit – – – – – – – – – – – – – – – – – – – – – – – – – – – 62 4.3.03 Growth Performance of Growing Rabbits – – – – – – – – – – – – – – – – – – – – – – – – – – – – – – –64 4.3.04 Serum Metabolite of Growing Rabbits – – – – – – – – – – – – – – – – – – – – – – – – – – – – – – — – -64 4.3.05 Thyroxine Levels in Growing Rabbits – – – – – – – – – – – – – – – – – – – – – – – – – – – – – – — – – 67 Experiment Four: 4.4 Effect of Graded Levels of BFPM on Reproductive Performance of Adult Rabbits – – – – – -69 4.4.01 Thermoregulatory Response of Adult Rabbit Bucks- – – – – – – – – – – – – – – – – – – – – – – – – 69 4.4.02 Serum Metabolites of Adult Rabbit Bucks – – – – – – – – – – – – – – – – – – – – – – – – – – – – – – – 71 4.4.03 Thyroxine Levels in Adult Rabbit Bucks – – – – – – – – – – – – – – – – – – – – – – – – – – – – – – — 74 4.4.04 Testosterone Levels in Adult Rabbit Bucks – – – – – – – – – – – – – – – – – – – – – – – – – – – – – – 74 4.4.05 Semen Quality Characteristics of Adult Bucks – – – – – – – – – – – – – – – – – – – – – – – – – – – – 74 4.4.06 Sperm Morphology of Adult Rabbit Bucks – – – – – – – – – – – – – – – – – – – – – – – – – – – – – -76
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4.4.07 Gonadal Morphometry of Adult Rabbit Bucks – – – – – – – – – – – – – – – – – – – – – – – – – – – – 76 4.4.08 Epididymis Morphometry of Adult Rabbit Bucks- – – – – – – – – – – – – – – – – – – – – – – – – – -78 4.4.09 Gonadal and Epididymis Sperm Reserves of Adult Rabbit Bucks- – – – – – – – – – – – – – – -78 4.4.10 Serum Metabolite of Adult Rabbit Does – – – – – – – – – – – – – – – – – – – – – – – – – – – – – – – – 81 4.4.11 Thyroxine Levels in Adult Rabbit Does Before, During and After Pregnancy — – – – – – -81 4.4.12 Progesterone Levels in Adult Rabbit Does Before, During and After Pregnancy – – – – – 84 4.4.13 Reproductive Performance of Adult Rabbit Does – – – – – – – – – – – – – – – – – – – – – – – – – –84 CHAPTER FIVE 5.0 DISCUSSIONS – – – – – – – — – – – – – – – – – – – – – – – – – – – – – – – – – – – – – — – – – – – – – – – – – 87 Experiment 1 5.1 Ameliorative Effect of Bicarbonate Buffer, Vitamin C and Baobab Fruit Pulp Meal on Growth Performance of Rabbits under Tropical Environment- – – – – – – – – – – – – – – – – – – – – – – 87 5.1.01 Temperature Humidity Index for Year A – – – – – – – – – – – – – – – – – – – – – – – – – – – – – – — 87 5.1.02 Thermoregulatory Response of Growing Rabbit – – – – – – – – – – – – – – – – – – – – – – – – – – – 87 5.1.03 Growth Performance of Growing Rabbits – – – – – – – – – – – – – – – – – – – – – – – – – – – – – – –88 5.1.04 Serum Metabolite of Growing Rabbits- – – – – – – – – – – – – – – – – – – – – – – – – – – – – – — – -89 5.1.05 Thyroxine Levels in Growing Rabbits – – – – – – – – – – – – – – – – – – – – – – – – – – – – – – — – -90 5.2 Experiment 2: Reproductive Performance Trial – – – – – – – – – – – – – – – – – – – – – – – – – – – – – -91 5.2.01 Thermoregulatory Responses of Adult Rabbit Bucks – – – – – – – – – – – – – – – – – – – – – – – -91 5.2.02 Serum Metabolites of Adult Rabbit Bucks – – – – – – – – – – – – – – – – – – – – – – – – – – – – – – -92 5.2.03 Thyrosine Levels in Adult Rabbit Bucks – – – – – – – – – – – – – – – – – – – – – – – – – – – – – – – – 92 5.2.04 Testosterone Levels in Adult Rabbit Bucks – – – – – – – – – – – – – – – – – – – – – – – – – – – – – – 93 5.2.05 Semen Quality Characteristics of Adult Rabbits Bucks – – – – – – – – – – – – – – – – – – – – – – -94 5.2.06 Sperm Morphology of Adult Rabbit Bucks – – – – – – – – – – – – – – – – – – – – – – – – – – – – – – -95
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5.2.07 Gonadal Morphometry of Adult Rabbit Bucks – – – – – – – – – – – – – – – – – – – – – – – – – – – – 95 5.2.08 Epididymis Morphometry of Adult Rabbit Bucks – – – – – – – – – – – – – – – – – – – – – – – – – – 96 5.2.09 Gonadal and Epididymis Sperm Reserves of Adult Rabbit Bucks- – – – – – – – – – – – – – – -97 5.2.10 Serum Metabolite of Adult Rabbit Bucks- – – – – – – – – – – – – – – – – – – – – – – – – – – – – – -98 5.2.11 Thyrosine Levels in Adult Rabbit Bucks – – – – – – – – – – – – – – – – – – – – – – – – – – – – – – – -99 5.2.12 Progesterone Levels in Adult Rabbit Bucks – – – – – – – – – – – – – – – – – – – – – – – – – – – – – -99 5.2.13 Reproductive Performance of Adult Rabbit Does – – – – – – – – – – – – – – – – – – – – – – – – – 100 Experimental Period for Year 2 5.3 Effect of Graded levels of Baobab Fruit Pulp Meal on Growth Performance of Rabbits under Tropical Environment – – – – – – – – – – – – – – – – – – – – – – – – – – – – – – — – – – – – – – – – – – – – – – – 101 5.3.01 Temperature Humidity Index inside the Rabbit house – – – – – – – – – – – – – – – – – – – – – – -101 5.3.02 Thermoregulatory Response of Growing Rabbit – – – – – – – – – – – – – – – – – – – – – – – – – – 101 5.3.03 Growth Performance of Growing Rabbits – – – – – – – – – – – – – – – – – – – – – – – – – – – – – – -102 5.3.04 Serum Metabolite of Growing Rabbits – – – – – – – – – – – – – – – – – – – – – – – – – – – – – – — – 103 5.3.05 Thyroxine Levels in Growing Rabbits – – – – – – – – – – – – – – – – – – – – – – – – – – – – – – — – 103 5.4 Reproductive Performance Trials – – – – – – – – – – – – – – – – – – – – – – – – – – – – – – — – – – – – – 104 5.4.01 Thermoregulatory Responses of Adult Rabbit Bucks – – – – – – – – – – – – – – – – – – – – – – – 104 5.4.02 Serum Metabolites of Adult Rabbit Bucks – – – – – – – – – – – – – – – – – – – – – – – – – – – – – – 104 5.4.03 Thyroxine Levels in Adult Rabbit Bucks – – – – – – – – – – – – – – – – – – – – – – – – – – – – – – –105 5.4.04 Testosterone Levels in Adult Rabbit Bucks – – – – – – – – – – – – – – – – – – – – – – – – – – – – – -106 5.4.05 Semen Quality Characteristics of Adult Rabbits Bucks- – – – – – – – – – – – – – – – – – – – – – 106 5.4.06 Sperm Morphology of Adult Rabbits Bucks– – – – – – – – – – – – – – – – – – – – – – – – – – – – -107 5.4.07 Gonadal Morphometry of Adult Rabbit Bucks – – – – – – – – – – – – – – – – – – – – – – – – – – – 108 5.4.08 Epididymis Morphometry of Adult Rabbit Bucks – – – – – – – – – – – – – – – – – – – – – – – – – 109
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5.4.09 Gonadal and Epididymis Sperm Reserves of Adult Rabbit Bucks – – – – – – – – – – – – – – -109 5.4.10 Serum Metabolite of Adult Rabbit Does – – – – – – – – – – – – – – – – – – – – – – – – – – – – – – – 110 5.4.11 Thyrosine Levels in Adult Rabbit Does Before, During and After Pregnancy – – – – – – -110 5.4.12 Progesterone Levels in Adult Rabbit Does Before, During and After Pregnancy – – – -111 5.4.13 Reproductive Performance of Adult Does – – – – – – – – – – – – – – – – – – – – – – – – – – – – – – -111 CHAPTER SIX 6.0 SUMMARY, CONCLUSION AND RECOMMENDATION – – – – – – – – – – – – – – – – – – – 113 6.1 Summary – – – – – – – – – – – – – – – – – – – – – – – – – – – – – – – – – – – – – – — – – – – – – – – – – – – – – 113 6.2 Conclusions – – – – – – – – – – – – – – – – – – – – – – – – – – – – – – – – – – – – – – — – – – – – – – – – – – – -114 6.3 Recommendations – – – – – – – – – – – – – – – – – – – – – – – – – – – – – – – – – – – – – — – – – – – – – – – 115 REFERENCES – – – – – – – – – – – – – – – – – – – – – – – – – – – – – – – – – – – – – — – – – – – – – – – – – – – -116
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CHAPTER ONE
1.0 INTRODUCTION One of the greatest challenges to successful livestock improvement and production in the tropics is heat stress. Reproduction in farm animals is highly affected by environmental factors and when environmental conditions are favorable, reproductive activity expresses its full potential. Favorable conditions must include adequate photoperiod, thermo-neutral conditions, food availability in quantity and quality, and a low stress environment (Marai et al., 2001). Inadequate conditions may lead to a decrease in growth and reproductive capacity, varying from sub-fertility to infertility. Therefore, the expression of growth and reproductive potentials is only possible when animals develop and establish a homeostatic equilibrium with their external environment (Marai et al., 2001) Almost annually heat waves kill thousands of different rabbit breeds in tropical countries, which cause economic losses to both rabbit breeders and consumers (Daader et al., 2003). The thermoneutral zone of growing rabbit (6-12 weeks of age) is 15-18oC. In tropical and sub-tropical countries, climatic heat is a major constraint on animal productivity; production and reproduction are impaired as a result of the drastic change in biological function caused by heat stress (Daader et al., 1997).
Feed intake and digestibility have been shown to reduce with increase in environmental conditions (Ayyat et al., 1996). Rabbits that were treated with 1.2% of potassium bicarbonate (KHCO3) buffer were reported to have improved performance (Fayes et al. 2011) during hot summer conditions in Egypt. Vitamin C (ascorbic acid) is one of the most widely studied vitamins used to alleviate heat stress in rabbits. It promots growth and improves reproduction in
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rabbits (Zeweil et al, 2009; Afifi and Makled 1995). Vitamin C is a good scavenger of free radicals hence serves as a good anti-oxidant (Zeweil et al, 2009). Baobab fruit bulb has been reported to contain high vitamin C (Odetokun, 1996; Adejuyitan et al. 2012). The use of Baobab fruit pulp in ameliorating heat stress in rabbits is yet to be explored. The aim of this study is to ameliorate the deleterious effect of heat stress with bi-carbonate buffer, vitamin C and baobab on growth and reproductive performance of rabbits reared under tropical environment. 1.1 Hypothesis: This study was designed to evaluate the following hypotheses: Ha: Bicarbonate buffer and vitamin C have an effect in ameliorating heat stress in rabbits during growth and reproductive phases under tropical condition. Ho: Bicarbonate buffer and vitamin C do not have an effect in ameliorating heat stress in rabbits during growth and reproductive phases under tropical condition. 1.2 Objectives of the Study The objectives of the study were to evaluate the effect of buffer, vitamin C and baobab:
1. on growth and reproductive performance of rabbits reared under tropical condition.
2. on thermoregulatory response and semen quality of rabbits reared under tropical condition.
3. on serum metabolites and hormonal profile of rabbits reared under tropical condition.
4. To determine the optimum level of baobab in ameliorating heat stress in rabbits under tropical condition.
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