4 luan an tien si ve protein tren bao ngu 2000

THE PROTEIN REQUIREMENTS OF THE SOUTH AFRICAN ABALONE, HALIOTIS MIDAE Submitted in fulfilment of the Requirements for the Degree of DOCTOR OF PHILOSOPHY Rhodes University by Thomas A Shipton December 1999 II CONTENTS ACKNOWLEDGEMENTS………………………….…………………………… IV ABSTRACT…………………………………………………….………………… V CHAPTER INTRODUCTION………………………………………….……… CHAPTER AN ASSESSMENT OF THE USE OF CHROMIC OXIDE IN DIGESTIBILITY TRIALS FOR HALIOTIS MIDAE…………………………………………………………… CHAPTER EVALUATION OF AN IN VITRO DIGESTIBILITY TECHNIQUE FOR THE PREDICTION OF PROTEIN DIGESTIBILITY IN FORMULATED FEEDS FOR HALIOTIS MIDAE………………………………………………… ………… 32 CHAPTER EFFECTS OF ANIMAL SIZE ON THE ABILITY OF HALIOTIS MIDAE TO UTILIZE SELECTED DIETARY PROTEIN SOURCES………………………………………………………… 49 CHAPTER REPLACEMENT OF FISHMEAL WITH SELECTED PLANT PROTEIN SOURCES IN FORMULATED FEEDS FOR JUVENILE HALIOTIS MIDAE…………………………………… 74 III CHAPTER INVESTIGATIONS INTO THE QUANTITATIVE AMINO ACID REQUIREMENTS OF HALIOTIS MIDAE……………….… 103 CHAPTER CONCLUDING DISCUSSION……………………………………… 120 REFERENCES……………………………………………………………………… 125 IV ACKNOWLEDGMENTS Many people have played a role in this work – peers, sponsors, friends Without my peers I wouldn’t have learnt how to approach the problems, without the sponsors I couldn’t have afforded to address the problems, and without my friends, well, I’d have packed up long ago and gone home…… so while I am grateful to them all, there are a number that I must mention individually Firstly, my supervisor Pete Britz As a student, supervisors come one-a-penny, and while in my time I seem to have crossed a few of their paths, Pete has been the exception Whether it has been persuading a non-surfing shark scared, pale pasty Englishman to jump off Port Alfreds West pier into barreling six foot surf; letting me wander off with my ideas about nutrition – and then, sometimes having to pick up the pieces; suggesting I take this or that into account; encouraging me through the darkest hours; the unenviable re-reading of scripts; what can I say Pete – thanks Much of the experimental work was carried out at the Port Alfred Marine Laboratory – endearingly known by those who work there as Legoland The work would not have been possible without both a sense of humour and the help from Bucs and Jerri What with Bucs and his experimental diving techniques, Jerri losing his beard, me, my refrigeration plant – I had a lot of fun, and can’t thank you enough for being there for my abalone The departmental statistical gurus Horst Kaiser and Tony Booth are thanked for their help deciphering the numbers Their courage in the face of continual barrages of daft questions will not go unforgotten Thanks to dear Madam Anu, may you rest in peace now, finally write up, and stop sending me microbiological papers through internal mail that complicate an already complicated life…… and of course Abby for the arguments I am indebted to my sponsors : Sea Plant Products ltd., Hermanus Abalone ltd., The National Research Foundation, Rhodes University Joint Research Committee and THRIP In particular, I’d like to thank Craig Clayden (Sea Plant Products Ltd.) for his infectious enthusiasm for the project, preparation of diets and the constant supply of experimental animals Marrianne Hundley for the University of Natal for her input with the amino acid work Mr Morley (Pharmacy Dept.) for advice, and allowing me access to his facilities Protein sources for the experimental diets were kindly donated by : EPOL SA, Esbjerg Fiskeindustri, Fiskernes Fiskeindustri, National Sorghum Breweries, Illova Sugars Ltd., Abakor Ltd., Sopropêche To Nico, KJ and Mr Aart – through the kaleidoscope of their sanity, they became the guardians of mine Indeed rare people that walk the earth Thank you for your love and support Candice – for whom words are a little difficult now, thank you for everything Rob – so the joke continues ! And finally to my parents, who have always held an unflinching belief in my education Back in the autumn of 1974 they packed a pink blazered little boy off to the Hall School, Hampstead Cap shorts and a cheesy grin – little did they know that his formal education would come to a close 25 years later ! For them mere gratitude is not enough V ABSTRACT The potential to reduce feed formulation costs by the replacement of existing protein sources in artificial feeds for Haliotis midae was assessed A comparison between the efficacy of the direct method and chromic oxide marker techniques in determining apparent protein digestibility coefficients, revealed that while the former was not a suitable methodology for use with this species, the latter produced replicable and reliable results It was established that the chromic oxide marker is inert, is not absorbed by the abalone, does not interfere with the digestive processes and moves through the intestine at the same rate to the protein However, as this method was time consuming and expensive to implement, a multienzyme pH-stat in vitro protein digestibility technique using a three enzyme system was employed to rapidly assess the protein quality of 34 protein sources The efficacy of the technique was established by correlating the in vitro digestibility estimates with in vivo digestibility coefficients obtained using the chromic oxide marker technique The highest degree of in vivo predictability was attained when protein sources were separated according to origin, and significant correlations between either animal (r2=0.89, P