Crocodile Par 2

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APPROVAL

I declare that this research project is my original work and has not been presented elsewhere.

Name of candidate: Shirley Nkwena

Student identity card number: 200601186

Signature

This research project has been presented with my approval as Supervisor

Dr K. B. Khare (Signature)

Date:...

Department of Biological Sciences

University of Botswana

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ABSTRACT

Determination of fungal infections in the Nile crocodile eggs was studied on the crocodile farm

in Samochima, Okavango, Botswana. The main objective was to determine fungal infection on

the unhatched Nile crocodile eggs and the sources of infection. Natural nests on the same village

were also studied for comparison. Fungal infections are a major problem on this farm with huge

early embryonic death. A total of 50 eggs were studied, 25 from the farm and 25 from the

natural nests (controls). Vermiculites, soils from farm and natural nests, feces from crocodile

laying mothers and livers from mortalities on the farm were also studied. Eggs were categorized

into EED-Early Embryonic deaths, VEED- Very Early Embryonic Deaths, II-Infertile Infected

and INI-Infertile Not Infected by use of candling method. All samples were cultured for the

presence of common fungal species at 25oC on Potato Dextrose Agar (PDA). Fungal infections

were determined from the egg membrane, egg yolk and albumen and all other samples cultured.

Slides were prepared from the fungal plates and observed under microscope. LCD (liquid crystal

display) microscope was used to take photographs of the fungi. Common fungal isolates from all

the samples cultured were those ofPenicillium, Aspergillus and Fusarium species. The same

fungi were isolated from farm and natural habitat eggs. These included Aspergillus flavus,

Aspergillus fumigatus, Aspergillus sydowi, Fusarium oxysporum, Fusarium moniliforme,

Penicillium granulatum and Penicillium oxalicum. Egg yolk, egg membrane and albumen had

fungi from three fungal species (Penicillium, Aspergillus and Fusarium). In addition to fungal

infections it was concluded that there might be other conditions responsible for the poor

hatchability and mortalities leading to loss of production at the Krokovango crocodile farm since

eggs from outside the farm had the same fungal isolates but had no problems of poor

hatchabilities.

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ACKNOWLEDGEMENTS

This study was supported by the University of Botswana in the Department of Biological

Sciences. Central to this support is the Krokovango crocodile farm manager Mr Zane Langman

in Samochima village, Okavango district who allowed me to carry out this investigation in their

farm and also providing crocodiles and eggs for research purposes. Farm workers are thanked

for their assistance in egg collection. Mr Sander Douma, a ph.D. Student investigating crocodile

farming research on the same farm led to the investigation of this study on the farm and Dr K. B.

Khare the supervisor provided valuable information and comments on the project and therefore,

contributed greatly to the success of this project. Laboratory technicians in the Biology

Department Mrs Tagwa, Mr Loeto and Mr Makobye helped me a lot with provision of materials

and guide on equipment usage.

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TABLE OF CONTENTS PAGE

TITLE PAGEi

APPROVAl.ii

APPROVAL ................................................................................................................... ii

I declare that this research project is my original work and has not been presented

elsewhere................................................................................................................... ii

ABSTRACT .................................................................................................................. iii

ACKNOWLEDGEMENTS ............................................................................................... iv

TABLE OF CONTENTS

PAGE .......v

INDEX OF TABLES ....................................................................................................... v

LIST OF FIGURES ........................................................................................................ vi

LIST OF ABBREVIATIONS ........................................................................................... vii

INDEX OF TABLES

Page

Table 1: Farm and natural nests clutch comparison...........................14

Table 2: Number of infected and dead eggs from the unhatched eggs in different clutches.16

Table 3: Fungal species from different categories and different parts of farm eggs.18

Table 4: Fungal species from different categories and different parts of natural habitat eggs..19

Table 5: Fungal species from nest soil collected from the farm and outside farm20

Table 6: Fungal species from the vermiculites and feces of crocodile laying mothers from the

farm21

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Table 7: Fungal species from the liver tissues of mortalities within the farm...................22

LIST OF FIGURES

Page

Fi

gure 1: Photograph of a cracked Nile crocodile egg from Krokovango farm..5

Figure 2: Photograph of Nile crocodile eggs from Krokovango crocodile farm covered with

vermiculites..6

Figure 3:Fusarium fungal species growing in PDA and isolated from Krokovango nest soil...7

Figure 4: Farm and natural nests comparisons..15

Figure 5: Number of infected and dead eggs from the unhatched eggs in different clutches17

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LIST OF ABBREVIATIONS

EED-Early Embryonic deaths

VEED- Very Early Embryonic Deaths,

II-Infertile Infected

INI-Infertile Not Infected

PDA-Potato Dextrose Agar

LCD-Liquid Crystal Display

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Crocodile Par 2