Open Research Online The Open University’s repository of research publications and other research outputs Nucleotide enhancement of diets, fish reproduction and egg quality Thesis How to cite: González Vecino, José Luis (2005). Nucleotide enhancement of diets, fish reproduction and egg quality. PhD thesis The Open University. For guidance on citations see FAQs. c 2005 José Luis González Vecino Version: Version of Record Link(s) to article on publisher’s website: http://dx.doi.org/doi:10.21954/ou.ro.00010190 Copyright and Moral Rights for the articles on this site are retained by the individual authors and/or other copyright owners. For more information on Open Research Online’s data policy on reuse of materials please consult the policies page. oro.open.ac.uk D in UHt Millennium Institute SCOTTISH '‘ÎasÈ!! / SAMSarc/foe ASSOCIATION fo r MARINE SCIENCE Nucleotide enhancement of diets, fish reproduction and egg quality José Luis Gonzalez Vecino A thesis submitted in partial fulfilment of the requirements of the Open University for the de^ee of Doctor of Philosophy Sponsoring establishment, UHI Millennium Institute Academic Partners, Seafish Aquaculture, nowadays SAMS Ardtoe and Scottish Association for Marine Science Commercial Partner: tn n a v a tia n Aquaculture October 2004 ProQuest Number: 27527246 All rights reserved INFORMATION TO ALL USERS The quality of this reproduction is dependent upon the quality of the copy submitted. In the unlikely event that the author did not send a com plete manuscript and there are missing pages, these will be noted. Also, if material had to be removed, a note will indicate the deletion. uest ProQuest 27527246 Published by ProQuest LLO (2019). Copyright of the Dissertation is held by the Author. All rights reserved. This work is protected against unauthorized copying under Title 17, United States C ode Microform Edition © ProQuest LLO. ProQuest LLO. 789 East Eisenhower Parkway P.Q. Box 1346 Ann Arbor, Ml 48106- 1346 Abstract Fish reproduction, and egg and larval quality are affected by broodstock nutrition. Nucleotides, the building bloeks of DNA and RNA, are now considered as semiessential nutrients during periods of food deficiency, stress, rapid growth and immunological stress. Since oogenesis is a process of intensive cell division with high nucleic acid formation and a concomitant high requirement for nucleotides, broodstock diets were enhanced with nucleotides. Their effects on the reproductive performance of Atlantic halibut (Hippoglossus hippoglossus L.) and haddock Melanogrammus aeglefinus L.), two cold water species with different life histories, were compared with control diets. Broodstock condition at the end of the spawning seasons did not differ between dietary treatments. However, dietary nucleotides improved total relative fecundity and batch relative feeundity of halibut and haddock respectively. Egg quality was also improved in both species. Fertilisation rate of haddock eggs and hatching rate in halibut and haddock eggs were significantly higher with the nucleotide diets. Nueleotide supplementation resulted in improved larval quality in both species. Survival of halibut larvae at the end of the yolk-sae stage was higher in the nucleotide group. Haddock larval survival five days after hatch was the same in both diets but improved at ten days post hatch as a result of significantly better developed gut and first feeding success in the nucleotide group. Histological examination of fish ovaries at the end of the experiment revealed no differences in the atresia levels. Nucleotide composition of egg and larval samples did not differ between diets, suggesting that dietary nucleotides were utilised by the broodfish to cover their nutritional requirements during oogenesis and reproduction. The enhanced reproductive performance in the nucleotide group is discussed in relation to a higher lipid mobilisation during oogenesis and quality of the yolk being consequently improved. Energy charge is confirmed as an egg quality indicator. 11 To my fam ily 111 Acknowledgements This research was fiinded by the UHI Millennium Institute, Ewos Innovation (Norway) and Seafish Industry Authority, and conducted between formerly Seafish Aquaculture Ardtoe - nowadays ^AM^Ardtoe Marine Laboratory - and the Seottish Assoeiation for Marine Scienee (SAMS). I would like to express my gratitude to Mr. Malcolm Gillespie, former director of Seafish Aquaculture and Professor Graham Shimmield, director of SAMS, for the use of the facilities. My sincere and deep gratitude to my supervisor, Dr. Christopher J. Cutts. Thanks for all your help, guidance, suggestions and encouragement throughout the entire project. I wish to express my gratitude to Dr. Robert S. Batty, Director of Studies, for his very useful comments and supervision too. Thanks to Dr. Carlos Mazorra de Quero for introducing me to the ‘aquaculture world’, your teaching and sharing your knowledge. Thanks to Yolanda Corripio and Carlos Mazorra, having them close made easier the long stays in Ardtoe. The suecess of this study would have been impossible without the support and assistance of the Ardtoe team; thanks to Les Ford and Gary Mclver for their assistance in the broodstock husbandry, to Jon Sherwood and Peter Smith for their guidance in the egg and larval rearing techniques; to Kay Robins and Hazel Cameron for preparing the live feed; to Eileen Cochrane and Monte Bleasdale for ordering all the consumables and to Jim Treasurer for his encouragement. I also wish to thank Simon Wadsworth (Ewos Innovation), former Seafish Aquaculture research manager, for making me feel part of the team since I first arrived to Ardtoe. I would like to aeknowledge Charles Burrells and Harald Sveier from Ewos Innovation for their support. Thanks to Dr. Peter Koeppel and Dr. Meinrad Schmid from Chemoforma Ltd. for hosting me on February 2002, and espeeially to Dr. Klaus Hoffmann for teaching me the basies of HPLC and the TP AN analysis. This training visit and various eonference attendances were possible thanks to the financial support of different organisations sueh as the UHI Millennium Institute, the Fisheries Society of the British Isles and Ewos Innovation. iv I would also like to aeknowledge Robin Harvey and Lupa Rodriguez (SAMS), and Dr. M.J. Caballero and Dr. J. Socorro (ICCM) for their help with the histological preparations. Thanks to Dr. Charles Bavington for the use of your microscope at Integrin, to Dr. Paul Greenhaff and John Fox for their assistance with the adenine nucleotide analyses and Chris Cutts, Mike Burrows and Bob Batty for guiding me through the ‘stats world’. My biggest gratitude goes to all my family but in particular to my Dad (nobody knows how much I miss you), Mum and sister because you were always there when I needed you. Thanks from my heart for your support and cheering me up. I am also indebted to my friends Bhavani Narayanaswamy, Rebecca Dean, Eduardo “Amobomgo”, Eva “Fibi”, Nacho and Francisco Ruiz. You know how hard the last months were for me, and together with my family kept me afloat. I would never have finished this ‘adventure’ without your encouragement, understanding, listening and advise. Nacho, your “red October hunt” saying encouraged me! Thanks to the footie gang for all those games, they kept my adrenaline levels low enough. To all the friends I have made at SAMS thanks for all the faney-dress parties, those “refreshments” in the pub and parties afterwards. I will never forget them, I will never forget you! iMuchas Graeias! Table of Contents Chapter 1: General introduction ............................................................................................... 1 1.1 Broodstock management ......................................................................................... 1 1.2 Biology of Atlantic halibut and haddock .......................................................................... 2 1.2.1 Atlantic halibut..................................................................................................... 2 1.2.2 Haddock ............................................................................................................... 4 1.3 Fish reproduction .............................................................................................................. 5 1.4 Nucleotides ........................................................................................................................ 9 1.4.1 Nomenclature and definition ................................................................................9 1.4.2 Nucleotide functions .......................................................................................... 11 1.4.3 Nucleotide metabolism ...................................................................................... 13 1.4.4 Research on nucleotides ..................................................................................... 14 1.4.4.1 Gastrointestinal effects ..............................................................................14 1.4.4.2 Nucleotides and lipids .............................................................................. 16 1.4.4.3 Hepatic effects.......................................................................................... 18 1.4.4.4 Immunological effects .............................................................................. 19 1.4.4.5 Nucleotide-enhanced diets and fish ..........................................................21 Chapter 2: Broodstock nutrition .............................................................................................25