ABSTRACT
Two experiments were conducted at the piggery unit of the Department of Animal Science Farm, University of Nigeria, Nsukka from June 2010 – September 2011, to determine the effect of dietary supplementation with vitamins E and C on the productive performance of pigs. The first experiment assessed the effect of dietary combinations of different levels of vitamins E and C on the growth performance of weaner pigs. Thirty six, Eight weeks old weaner gilts were used for this trial. They were randomly assigned to nine experimental treatment diets having different combinations of vitamins E and C (0 mg vitamin C/0 iu vitamin E (T1), 250 mg vitamin C/0 iu vitamin E (T2), 500 mg vitamin C/ 0 iu vitamin E (T3), 60 iu vitamin E/0 mg vitamin C (T4), 60 iu vitamin E/250 mg vitamin C (T5), 60 iu vitamin E/500 mg vitamin C (T6), 120 iu vitamin E/0 mg vitamin C (T7), 120 iu vitamin E/250 mg vitamin C (T8), 120 iu vitamin E/500 mg vitamin C (T9) with four gilts per treatment. The gilts were housed in pairs making up two replicates per treatment. The initial body weights and linear body measurements of the gilts were recorded before the start of the experiment. Thereafter, weekly body weights and linear body measurements were taken and continued till the gilts attained puberty at the age of 5 months. One experimental diet with 18% crude protein (CP) and 2800 kcal/kgME was formulated for the gilts in the nine treatments but had different levels of vitamins E and C assigned to each treatment. The vitamins were administered through the feed at the time of feeding. In experiment 2, sixteen gilts were selected out of 36 gilts from experiment 1 and randomly assigned to four dietary treatments to evaluate the effects of the combinations of vitamins E and C on the reproductive performance of gilts. Each treatment was replicated twice with two gilts per replicate making up four gilts per treatment. One experimental ration containing 15% CP and 2500kcal/kgME was used but different levels of vitamins E and C for each treatment were added to the feed at the time of feeding. The gilts were placed on the gestation/lactation diet immediately after selection and were allowed to attain their second estrus before mating took place. The body weight of the gilts were recorded before mating following the manifestation of second estrus and date of mating recorded. Gilts were fed 2.0kg of 15% CP diet each day when pregnancy was confirmed. Weekly body weights of the gilts were subsequently taken throughout the gestation period. At farrowing, their ration was increased to 2.6kg per pig per day until piglets were weaned at the age of 8 weeks. The birth weights of the piglets were recorded within 24 hours of parturition, and subsequently piglet weekly body weights were recorded until weaning. Similarly, the body weights of the lactating sows were taken weekly to monitor their body weight changes during lactation. All the data in both experiments one and two were processed and analyzed in accordance with 3 x 3 and 2 x 2 factorial arrangement, respectively in a completely randomized design (CRD). Results of experiment one showed a significant (P<0.05) interaction of vitamins E and C on the body weight of gilts. Weaner pigs on T5 diet containing 60iu and 250mg of vitamins E and C, performed significantly better (P<0.05) in terms of average final body weight (66.13 ± 2.49kg) and growth rate (633.50 ± 30.34g/day) than those in other treatments. However, feed intake and feed conversion ratio were comparable (P>0.05) among the nine treatments. There were significant differences (P<0.05) in flank-to-flank lengths among the gilts in the treatments, with T1 and T2 having the highest values of 67.13 ± 1.82cm and 67.25 ± 1.23cm, respectively. Gilts on T5 had the highest (P<0.05) heart girth values of 83.68 ± 1.22cm, while gilts on T8 and T9 had comparable but lower heart girth of 65.08 ±1.42cm and 65.00 ± 1.06cm, respectively. Significant interaction (P<0.05) effects of vitamins E and C were observed in body weight, weight gain, flank-to-flank and heart girth measurements of gilts at puberty. In the reproductive phase, average litter size values of 7.00 ± 0.58, 8.00 ± 0.41, 8.00 ± 0.00 and 7.00 ± 1.00 for T1, T2, T3 and T4, respectively and the corresponding birth weight mean values of 0.97 ± 0.08kg, 1.05 ± 0.11kg, 1.19 ± 0.00kg and 1.24 ± 0.03kg were not significantly different (P>0.05) among the treatments. Significantly lower (P<0.05) pre-weaning body weight gain (g/day/piglet) was observed for piglets on T1 with mean value of 126.25 ± 5.62 compared to piglets on T2, T3 and T4 with respective values of 150.77 ± 5.00, 150.51 ± 1.59 and 164.12 ± 7.23. A range of 22.07 ± 3.45% to 25.10 ± 0.10% pre-weaning mortality was observed across treatments. Piglets on T1 had the least weaning weight of 7.25 ± 0.28kg which differed significantly (P <0.05) from piglets on T2, T3 and T4 with weaning weights of 8.42 ± 0.24kg, 8.62 ± 0.08kg and 8.71 ± 0.60kg, respectively. The highest (P <0.05) gestation weight gain of 50.20 ± 0.20kg was recorded for gilts on T3 while the least (P <0.05) gestation weight gain of 44.33 ± 4.48kg was observed in gilts on T1.
This study finally suggested that a combination of 60 iu vitamin E/250 mg vitamin C, and supplementation of 120 iu vitamin E alone are more suitable for the improvement of growth performance of pigs managed intensively, while dietary vitamins E and C supplementation at 0 iu vitamin E/250 mg vitamin C, 120 iu vitamin E/0 mg vitamin C and 120 iu vitamin E/250 mg vitamin C combinations during gestation of gilts and their lactation will effectively enhance litter size and lactation performance.
TABLE OF CONTENTS
Pages
Title page—————————————————————————————- i
Certification————————————————————————————- ii
Dedication————————————————————————————– iii
Acknowledgement—————————————————————————– iv
Abstract —————————————————————————————- v
Table of contents —————————————————————————— vii
List of tables ———————————————————————————- xii
CHAPTER ONE ——————————————————————————————— 1
1.0 INTRODUCTION————————————————————————————— 1
1.1 Statement of Problem———————————————————————– 3
1.2 Objectives of the Study——————————————————————— 4
1.3 Justification of the Study——————————————————————- 4
CHAPTER TWO——————————————————————————————— 6
2.0. REVIEW OF LITERATURE———————————————————————– 6
2.1 Origin of Pig(s)—————————————————————————– 6
2.1.1 Description of Pig(s)———————————————————————- 6
2.1.1.1 History———————————————————————————- 6
2.1.1.2 Anatomy——————————————————————————– 6
2.1.1.3 Trend in Pig Production—————————————————————- 7
2.2 Growth in Animals————————————————————————————8
2.2.1 Definitions of Growth——————————————————————– 8
2.2.2 Growth in Pig(s)————————————————————————– 9
2.2.3 Influence of Nutrition on Pig’s Growth————————————————- 10
2.2.4 Hormonal Control of Growth———————————————————– 11
2.2.5 Effect of Temperature on Pig’s Growth————————————————- 14
2.2.6 Influence of Temperature on Piglets’ Survival—————————————— 16
2.2.7 Post-natal Growth in Pigs————————————————————— 17
2.3 Vitamin E (Alphatocopherol)————————————————————– 20
2.3.1. Vitamin E Deficiency in Pigs ———————————————————- 21
2.3.2 Clinical Signs of Vitamin E Deficiency in Pigs —————————————- 22
2.3.3 Effect of Dietary Vitamin E Supplementation at Different Physiological Stages
in Swine Production————————————————————————— 22
2.3.3.1 Supplementation with Vitamin E at Post-weaning Stage—————————– 23
2.3.3.2 Supplementation with Vitamin E at Gestation and Lactation Stages—————– 24
2.3.4 Influence of Vitamin E Absorption on Pig Performance——————————– 24
2.3.4.1 Steps for Absorption of Supplemental Vitamin E Esters in Pigs———————- 26
2.3.5 Sources of Vitamin E —————————————————————— 28
2.3.6 Influence of Vitamin E on the Growth of Pigs————————————————29
2.4. Vitamin C (Ascorbic Acid)————————————————————— 33
2.4.1 Biological Action of Vitamin C——————————————————— 34
2.4.2. Vitamin C Deficiency—————————————————————— 34
2.4.3. Metabolic Functions of Vitamin C—————————————————– 34
2.4.4. Synthesis of Vitamin C by Pigs——————————————————— 35
2.5. Influence of Vitamins C and E on Growth Performance Of Pigs ———————– 36
2.6 Reproduction in Pigs———————————————————————- 39
2.6.1 On-set of Reproductive Activities in Pigs———————————————– 39
2.6.2 Factors that Influence Reproductive Activities in Pigs——————————— 41
2.6.2.1Climate——————————————————————————— 42
2.6.2.2 Nutrition——————————————————————————- 42
2.6.2.3 Oestrus ——————————————————————————– 43
2.6.2.4 Age at First Mating——————————————————————– 43
2.6.2.5 Litter Size—————————————————————————— 43
2.6.2.5.1 Relationship Between Litter Size, Weaning Weight, Birth Weight and
Pre-Weaning Losses in Pigs——————————————————————- 45
2.6.2.5.2 Factors that Influence Litter Size in Pigs——————————————– 46
2.6.2.5.2.1 Weight at First Mating———————————————————— 46
2.6.2.5.2.2 Effective Breeding and Timing————————————————— 46
2.6.2.5.2.3 Feeding in Early Gestation——————————————————– 46
2.6.2.5.2.4 Lactation Length—————————————————————— 46
2.6.2.5.2.5 Weaning to Standing Oestrus—————————————————– 47
2.6.2.5.2.6 Parity Distribution —————————————————————- 47
2.7 Pre-weaning Mortality——————————————————————— 48
2.8 Weaning of Piglets———————————————————————— 50
2.8.1 Early Weaning in Pigs——————————————————————- 50
2.8.2 Weaning Age in Relation to Weaning Weight, Birth weight, Pre-weaning Growth
and Litter Size——————————————————————————— 52
2.9 Influence of Vitamins C and E Supplementation on the Reproductive Performance
of pigs—————————————————————————————– 53
2.10. Influence of Immunomodulatory Properties of Vitamins E and C on the Performance
of Pigs—————————————————————————————– 61
2.11. Free Radicals in Animal Production—————————————————– 67
2.12. Antioxidant Defense System of the Animal Body————————————– 68
2.12.1. The Necessity for Dietary Antioxidant Combination ——————————– 70
2.12.2. Proven Antioxidation Effects in Swine Production———————————– 71
2.13. Optimum Vitamin Allowance in Animals———————————————– 74
CHAPTER THREE—————————————————————————————- 75
MATERIALS AND METHODS———————————————————————– 75
3.1 Location and Duration of the Study—————————————————— 75
3.2 Management of Experimental Animals—————————————————- 75
3.3 Experimental Procedure——————————————————————- 76
Experiment 1 —————————————————————————— 76
Experiment 2——————————————————————————- 78
3.4 Statistical Analysis———————————————————————— 82
CHAPTER FOUR—————————————————————————————— 83
RESULTS—————————————————————————————————– 83
4.0 EXPERIMENT 1: Effect of Dietary Supplementation with Levels of Vitamins E and C
On the Growth Performance of Gilts.——————————————————– 83
4.1Main effect of dietary supplementation with vitamins E and C levels on the body
weight, daily feed intake, weight gain and feed conversion ratio of gilts——————– 86
4.2 Main effect of Dietary Supplementation with Vitamins E and C Levels on Linear Body
Measurements of Gilts at Puberty.———————————————————— 86
4.2.1 Body Length (cm)———————————————————————– 86
4.2.2 Flank-to- Flank (cm)——————————————————————————87
4.2.3 Heart Girth (cm)————————————————————————- 87
4.3 The interaction effect of Dietary Supplementation with Levels of Vitamins E and C
on the growth performance of Gilts.———————————————————- 88
4.4Experiment 2——————————————————————————- 93
4.4.1Conception rate (%)———————————————————————- 95
4.4.2 Gestation length (days)—————————————————————— 95
4.4.3 Average litter size (no)—————————————————————————95
4.3.4 Average Birth Weight of Piglets (kg)————————————————— 95
4.3.5 Average Pre-weaning Piglet Mortality (%)———————————————- 96
4.3.6 Average Pre-weaning Growth Rate of Piglets (g/day)———————————- 96
4.3.7 Average Weaning Weight of Piglets (kg)———————————————– 97
4.3.8 Average Litter Size at Weaning ——————————————————– 97
4.3.9 Gestation Weight Gain of Gilts (kg)—————————————————- 97
4.3.10 Lactation Weight Loss of Sows (kg)————————————————— 97
CHAPTER FIVE——————————————————————————————- 98
DISCUSSION———————————————————————————————— 98
5.0  Experiment 1—————————————————————————- 98
5.1 Effect of Dietary Supplementation with Levels of Vitamins E and C on the Growth
Performance of Gilts.————————————————————————– 98
5.1.2 Effect of Dietary Supplementation with Levels of Vitamins E and C on the Linear
Body Measurements of Gilts—————————————————————– 100
5.2 Effect of Levels of Vitamins E and C Supplementation on the Reproductive
Performance of Gilts———————————————————————— 102
5.3 Conclusion——————————————————————————- 108
REFERENCES——————————————————————————————– 110
CHAPTER ONE
1.0 INTRODUCTION
Meat is becoming a highly scarce commodity especially at a time when staples like garri, cowpea and rice can not be reached by many consumers as a result of the global food crisis which is currently plaguing the country as well as many other countries in the world.
Due to the expensive nature of poultry meat and egg, beef, mutton, pork, chevron etc, people now have resorted to frozen fish consumption which was ignored years ago. Shortage of protein particularly those of animal origin, is prevalent, not only in Nigeria but also in most parts of Africa, where it is estimated that on the average, 10g of animal protein is consumed per day per person, compared to a recommended daily intake of 35g (ILCA, 1980).The level of consumption of meat and animal protein in Nigeria is estimated at about 8g per caput per day, about 27g less than the minimum requirement by the National Research Council of the United State of America. Despite the progress made in pig production, current production levels especially in the developing countries are still less than the biological potentials of pigs.
Pig production in Nigeria today, has been adversely affected by a number of factors, which can be traced to environmental, nutritional, management and perhaps, genetic factors. When a stock with high genetic potential is in place, these other factors need to be totally controlled before high production will be achieved. Controlling these, will impact positively on the animals’ overall productivity.
Again, the fear created by the emergence of avian influenza (avian flu) has negatively affected animal protein intake of Nigerians. The large number of backyard household poultry enterprises have reduced due to the dread of the ominous consequences of the avian flu outbreak. This has therefore kept poultry products out of the reach of the poor urban and rural dwellers.
Pig production therefore, seems to be the likeliest and quickest means of solving the problem of insufficient animal protein intake, especially in the Southern and Middle-Belt zones of Nigeria, where pork is not discriminated against.
Also, considering the sustained pressure on livestock producers to reduce environmental impacts and optimize animal welfare, the on-going pursuit of advances in nutrition of which this research is part of, will be fundamental to the sustainability of pig production. Pig and poultry unlike ruminants, according to Preston (1990) do not produce methane and therefore are regarded as being environmentally friendly.
Among the factors that militate against animal performance, biological free radicals have been strongly implicated as one of the major causes of poor performance and low productivity in a high intensive animal production. In the event of the failure of the tissue antioxidant defense system to stabilize the activities of the free radicals, which have potentially detrimental effects on animal performance and are highly reactive, these continue to be generated leading to tissue and cell destructions. This will have very negative effects on the productive potential of the animals. Therefore, delivery of supplemental antioxidant vitamins to domestic animals in confinement might improve health and performance outcomes by reducing the effects of oxidative stress to which these animals are presumably exposed. The health outcome of morbidity and the production outcomes of weight gain and feed conversion ratio, are expected to be improved.
Supplementation with levels of feed additives has been used in swine feeds since 1950’s for improved growth rate and feed efficiency and to maintain pig performance. The most effective use is in the diets of weanlings and young growing pigs, but good responses are also obtained in finisher and breeding swine (Zimmerman, 1986).
The consistent effectiveness of feed additives in enhancing pig performance has led to their extensive use in swine feeding industry. Cromwell (2001) estimated that 80 to 90 % of all starter pig feeds, 70 to 80 % of all finisher pig feeds and 40 to 50 % of all sow feeds, are fortified with one form of additives or the other. Vitamins however, are not excluded from these additives that enhance and promote the performance of animals.
Vitamin E is a fat soluble vitamin of plant origin, essential for the integrity and optimal function of the reproductive, muscular, circulatory, neurons and immune systems. It is known for its role as an anti-oxidant, protecting unsaturated bond of cellular membrane phospholipids against free radical attack (Tappel, 1972). The immuno-modulatory effects of vitamin E, have been demonstrated in human and variety of animal species and were most evident in very young, very old and immunocompromised individuals (Tengerdy et al., 1984; Meydani, 1995).
Vitamin C is a white crystalline acid, which is widely distributed in certain fruits and vegetables. Its deficiency may lead to scurvy (Hartman –Petersen and Pigford, 1984). It is generally assumed that pigs can synthesize vitamin C and do not need dietary supplementation in most conditions (N.R.C, 1998). However, there is evidence that in certain conditions, pigs may need supplemental vitamin C for maximum weight gain (Yen and Pond, 1981).
Vitamins E and C are primary antioxidants in biological systems that break the chain of lipid peroxidation (Gey, 1998). Hoechler and Marquardt (1996) showed that vitamin C enhanced the biological efficacy of vitamin E, thus, the interaction between vitamin E and C affected performance in growing pigs.
1.1 STATEMENT OF PROBLEM
In an intensively managed piggery, pigs experience both low and high levels of antigen exposure. This type of husbandry predisposes the animals to infection and stress which may usually arise from the metabolic products of the animals and other factors as a result of the animals’ confinement.
Due to infection and stress, the immunity of the pigs may be compromised leading to poor performance. Therefore, in order to achieve high efficiency in both growth and reproductive performance of pigs, there is a great need of dietary vitamins E and C supplementation for pigs. Vitamins E and C are known to possess both antioxidant and immuno-modulatory properties that will enable pigs exposed antigenically to perform optimally.
1.2 OBJECTIVES OF THE STUDY
The broad objective of the study was :-
To evaluate the effect of dietary combinations of different levels of vitamins E and C on some performance characteristics of the pigs.
The specific objectives were to:
(i) to assess the growth performance of weaner pigs fed combinations of different levels of vitamins E and C .
(ii) to evaluate the effect of the combinations of vitamins E and C on the reproductive performance of gilts.
1.3 JUSTIFICATION OF THE STUDY
Ayo and Oladele (1996) noted that in order to achieve high rate of efficiency and live weight gain of pigs, there is a great need of vitamins E, C and A supplementation for pigs experiencing low or high levels of antigen exposure.  Intensive pig production requires fast growing strains, usually at high stocking densities and in a more confined state.
With this type of husbandry, flocks are highly susceptible to infectious agents and stressful conditions, which may arise, not only from the metabolic products of the animals in a confined state but also from other factors. These infectious agents and the stressful conditions, may compromise the immune potentials of the animals thereby reducing their ability to perform optimally. In this regard, the significance of vitamins E and C which are known to have antioxidant and immuno-responsive properties can not be over emphasized.
When pigs are intensively raised, they are antigenically exposed. This results in immune system activation. Therefore, the dietary inclusion of antioxidant vitamins such as vitamins E and C in an intensively managed piggery could potentially minimize negative effects of free radicals on the productivity of farm animals.
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