effects of magnesium supplementation on physiological parameters in captive cheetah

137 Pages·2012·1.14 MB·English

by  Johan Grobler

Effects of dietary magnesium supplementation on
physiological parameters in captive cheetahs
(Acinonyx jubatus) at Hoedspruit Endangered
Species Centre (HESC)
by
Johan Grobler
B.Sc (Agric) Animal Science (Pret.)

Submitted in partial fulfillment of the requirements for the
degree

Magister Scientiae Agriculturae

(Production Physiology)

In the Faculty of Natural and Agricultural Sciences
Department of Animal and Wildlife Sciences

University of Pretoria
Pretoria
November 2011
Promoter: Prof. E.C. Webb

©© UUnniivveerrssiittyy ooff PPrreettoorriiaa
DECLARATION
_____________________________________________
I, Johan Grobler, declare that the dissertation: “Effects of dietary magnesium
supplementation on physiological parameters in captive cheetah (Acinonyx
jubatus) at Hoedspruit Endangered Species Centre (HESC)” which I hereby
submit for the degree M.Sc (Agric) Production Physiology at the University of
Pretoria, is my own work and that all the sources that I used or quoted have been
indicated with complete reference and acknowledgements. This dissertation has not
previously been submitted by me for a degree at this or any other tertiary institution.

JOHAN GROBLER DATE

I
DEDICATION
_____________________________________________
To Lenaldi and my family, for your love and support which fuelled my commitment to
this journey and whose involvement motivated me to the end.

II
ACKNOWLEDGEMENTS
_____________________________________________
 Most importantly my Heavenly Father who blessed me with the privilege to
pursue my studies.
 My study leader, Professor Webb for your creativity and constant support to stay
on course.
 Lenaldi who did my language editing.
 Me. Lente Rhoode, the curator Christo and the staff at the HESC for your friendly
hospitality during my stay as well as all your help. This study would not be
possible without you.
 Me. Lente Rhoode and the HESC for financially sponsoring this study.
 The two veterinarians Dr. Brett Gardner and Dr. Greg Simpson and all the other
people who helped and guided me along the way.

III
ABSTRACT
_____________________________________________
Effects of dietary magnesium supplementation on physiological
parameters in captive cheetah (Acinonyx jubatus) at Hoedspruit
Endangered Species Centre (HESC)
by

Johan Grobler

Promoter: Prof. E.C.Webb

Faculty: Faculty of Natural and Agricultural Sciences
Department: Department of Animal and Wildlife Sciences
Degree: Magister Scientiae Agriculturae
(Production Physiology)

The last 50 years was characterized by a dramatic decrease in free-roaming cheetah
populations and consequently the cheetah now appears on the IUCN Red List for
Threatened Species. In order to save cheetahs from extinction, a number of projects
were launched to breed cheetahs in captivity. Captive cheetahs, however, receive
fundamentally different diets than their free-roaming counterparts, which
necessitates feed supplementation to fulfill their unique dietary needs.
The Hoedspruit Endangered Species Centre (HESC) is one such project aiming to
breed captive cheetahs. At the HESC, a number of juvenile cubs were diagnosed
with a form of relaxed carpal joints, namely metacarpal deformity of the front legs.
Literature suggests that the condition is due to a magnesium deficiency, which is a
consequence of an unbalanced diet. Supplementing magnesium to the diet of
cheetahs can, however, affect the urinary system negatively: such as the formation
of urolithiasis.
IV
The aim of this study was to determine whether dietary magnesium supplementation
in the diets of captive cheetahs will remedy metacarpal deformity and also to
investigate the influence of magnesium supplementation on the formation of
urolithiasis.
The study was divided into two phases. Phase 1 was conducted to determine the
influence of dietary magnesium supplementation on metacarpal deformity, identified
in juvenile cheetahs at the HESC. To determine the degree of deformity, a leg
deformity scoring system was developed. On a scale from 1-3, the cheetahs were
scored twice to determine the Flexed Deformity Score (FDS) and Rotational
Deformity Score (RDS) values before and after dietary magnesium supplementation.
Phase 2 was conducted to determine the influence of magnesium supplementation
on different physiological parameters that have an influence on the formation of
urolithiasis. Phase 2 was divided into three periods. During each period, the
cheetahs received a different diet. During period C, the experimental period, the
cheetahs were divided into two groups. One group received a meat-only diet,
whereas the other group received a meat-Mg diet. At the end of each of the three
periods, blood- and urine samples were collected and analyzed to determine the
concentration of minerals in the cheetah’s blood plasma and urine.
Based on the FDS and RDS scores, a 25.5% response rate to dietary magnesium
supplementation on rotational deformities was found, whereas a 60.8% response
rate on flexural deformation was found. It is thus concluded that dietary
supplementation of magnesium in juvenile cheetahs that experience metacarpal
deformities, will remedy the deformity.
By analyzing the changes of different blood- and urine parameters in the cheetahs it
was observed that dietary magnesium supplementation do influence the formation of
urolithiasis. The physiological state of the cheetahs can influence these parameters.
The results obtained from the study can be utilized by nutritionists, veterinarians and
institutions to enhance the health of captive cheetahs.
V
TABLE OF CONTENT
_____________________________________________
Page
TITLE
DECLARATION I
DEDICATION II
ACKNOWLEDGEMENTS III
ABSTRACT IV
TABLE OF CONTENT VI
LIST OF FIGURES XI
LIST OF TABLES XII
LIST OF DIAGRAMS XIV

CHAPTER 1: INTRODUCTION 1
1.1 Background 1
1.2 Problem statement 2
1.3 Aim of study 3
1.4 Relevance of the study 3
1.4.1 Taxonomy of the cheetah 3
1.5 Structure of the dissertation 5
1.6 Ethical consideration 6

CHAPTER 2: FEEDING PRACTICES 7
2.1 Introduction 7
2.2 Feeding practices of free-ranging cheetahs 7
2.3 Feeding practices of cheetahs in captivity 9
2.3.1 Feeding whole carcasses 9
2.3.2 Feeding supplemented meat 10
VI
2.4 Nutritional imbalances due to diet 12
2.5 Summary 14

CHAPTER 3: PHYSIOLOGICAL CONDITIONS 15
3.1 Introduction 15
3.2 Metacarpal deformity 15
3.2.1 Anatomy of the forelimb 16
3.2.1.1 Skeleton of the forelimb 16
3.2.1.2 Joints of the forelimb 18
3.2.1.3 Muscles of the forelimb 19
3.2.2 Skeletal muscle anatomy and contraction 20
3.2.2.1 Structure 20
3.2.2.2 Muscle contraction 20
3.2.3 Flexural deformities 21
3.2.4 Summary 24
3.3 Role, control and regulation of calcium, magnesium and 24
phosphorous in the body
3.3.1 Role and regulation of magnesium 25
3.3.2 Role and regulation of calcium 27
3.3.3 Role and regulation of phosphorous 28
3.3.4 Interaction between magnesium, calcium and phosphorous 29
3.3.5 Summary 30
3.4 Urolithiasis 31
3.4.1 Lower urinary tract diseases (LUTD) 31
3.4.2 Different types of stones 35
3.4.2.1 Struvite 35
3.4.2.2 Calcium oxalate 36
3.4.3 Factors that influence stone formation 38
3.4.3.1 Urinary pH 38
3.4.3.2 Mineral imbalances 38
3.4.3.3 Protein 40
3.4.3.4 Bacterial infection 40
VII
3.4.3.5 Chemicals 41
3.5 Summary 42

CHAPTER 4: RESEARCH METHODOLOGY 43
4.1 Introduction 43
4.2 Experimental design 43
4.3 Research methodology 43
4.3.1 Experimental layout 44
4.3.1.1 Phase 1: Within-subjects design 47
4.3.1.2 Phase 2: Within-subjects design and between-subjects 47
design
4.3.2 Subjects used and treatment groups 48
4.3.3 Treatment conditions and –level 49
4.3.4 Independent variable 50
4.3.5 Dependent variable 50
4.3.6 Treatment effect 51
4.3.7 Feed preparation 51
4.3.8 Available resources 52
4.4 Flexural deformity 52
4.4.1 Leg deformity scoring 53
4.4.2 Scoring method 53
4.5 Mineral analyses 55
4.5.1 Sampling procedures 55
4.5.1.1 Blood samples for magnesium and calcium analyses 56
4.5.1.2 Blood samples for phosphorous analysis 56
4.5.1.3 Urine samples 57
4.5.2 Laboratory serum and plasma analyses 57
4.5.2.1 Magnesium and calcium analyses 57
4.5.2.2 Phosphorous analysis 58
4.5.3 Laboratory urine analysis 58
4.5.3.1 pH 59
4.5.3.2 Minerals 59
VIII
4.5.3.3 Nitrogen 59

CHAPTER 5: RESULTS AND DISCUSSION 61
5.1 Introduction 61
5.2 Metacarpal deformity 61
5.2.1 Rotational deformity 65
5.2.2 Flexural deformity 65
5.2.3 Summary 66
5.3 Urolithiasis 66
5.3.1 Urinary pH and body weight 67
5.3.1.1 Summary for urine pH and body weight 75
5.3.2 Urinary nitrogen 76
5.3.2.1 Summary for nitrogen 84
5.3.3 Urine- and plasma minerals 84
5.3.3.1 Phosphorous 94
5.3.3.2 Magnesium 96
5.3.3.3 Calcium 99
5.3.3.4 Potassium, sodium and sulphur 100
5.3.3.5 Summary for minerals 101

CHAPTER 6: CONCLUSIONS AND RECOMMENDATIONS 105
6.1 Introduction 105
6.2 Conclusions 105
6.2.1 Conclusions regarding aim 1.3a) 105
6.2.2 Conclusions regarding aim 1.3b) 106
6.3 Limitations 106
6.4 Recommendations 106
LIST OF REFERENCE 108

APPENDICES
IX