Blood Metabolites As Markers for the Nutritional Status in Ethiopian Livestock
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Blood metabolites as markers for the nutritional status in Ethiopian livestock Word count: 13.021 Floortje van de Meulengraaf Student number: 01611842 Supervisor: Prof. Dr. ir. Geert Janssens Supervisor: Ketema Worku A dissertation submitted to Ghent University in partial fulfilment of the requirements for the degree of Master of Veterinary Medicine Academic year: 2018 - 2019 Ghent University, its employees and/or students, give no warranty that the information provided in this thesis is accurate or exhaustive, nor that the content of this thesis will not constitute or result in any infringement of third-party rights. Ghent University, its employees and/or students do not accept any liability or responsibility for any use which may be made of the content or information given in the thesis, nor for any reliance which may be placed on any advice or information provided in this thesis. Acknowledgements This thesis would not have been possible without the help and support of several people, and therefore I would like to include a few words of thanks. Since my first visit, Africa has a special place in my heart, so I can only say that I am extremely happy that I had the chance to conduct my research in Arba Minch, Ethiopia. For this I would like to first of all thank my promoter Prof. Dr. Ir. Geert Janssens. You were a great help during the writing process, without your feedback and our discussions I would never have remained so sharp. I would also like to thank Dr. Donna Vanhauteghem very much for her distant support when I was in Ethiopia. It was very nice that you were able to help us, time after time, with our frustration in the research. Ketema Worku, as co-promoter, I would like to thank him for his help in Ethiopia. You did not only help with the research but also took us into the Ethiopian culture, which was fantastic. I would like to thank Yisehak Kechero Kebede for his help in Ethiopia itself and to welcome us at the Kulfo campus (College of agricultural sciences). Then I would also like to thank my companion in Ethiopia. Annet also called Alex, I thought it was great to go on this adventure with you, even if it was sometimes "crying with the cap on" during our research. I wouldn't have wanted to beat anyone else at checkers. While waiting, until the playing monkeys on the roof were gone and we had power again so we could work with "ferry" the spectrophotometer again. Lisette thanks that you, despite your own busy schedule, could make time to upgrade my master's thesis in the English language. Finally, I would like to thank my parents, family and friends for their support and encouragement during my years of study. I promise not to miss any birthday parties or other special moments from now on. A part of the financial costs was covered by the VLIR-UOS travel grant 2018. Table of contents I Abstract _____________________________________________________________________ 6 II Samenvatting _________________________________________________________________ 7 III Introduction __________________________________________________________________ 8 IV Literature survey _____________________________________________________________ 10 IV.1 The “normal” digestion and metabolism of ruminants _________________________ 10 IV.1.1 Digestion and metabolism of carbohydrates ____________________________ 11 IV.1.2 Digestion and metabolism of protein _________________________________ 11 IV.1.3 Digestion and metabolism of lipids ___________________________________ 12 IV.2 Metabolic interaction in ruminants ______________________________________ 13 IV.3 Metabolic adaptation in tissue in times of negative energy balance. _______________ 16 V Research aims _______________________________________________________________ 19 VI Material and methods _________________________________________________________ 20 VI.1 Description of the study area ___________________________________________ 20 VI.2 Animals __________________________________________________________ 21 VI.3 Feed ____________________________________________________________ 21 VI.4 Blood sample collection and preparation __________________________________ 22 VI.5 Analysis __________________________________________________________ 22 VI.5.1 Spectrophotometer _____________________________________________ 22 VI.5.2 Acylcarnitines __________________________________________________ 25 VI.5.3 Statistics ______________________________________________________ 25 VII Results ___________________________________________________________________ 26 VII.1 Body condition score _______________________________________________ 26 VII.2 Milk yield _______________________________________________________ 27 VII.3. Spectrophotometer________________________________________________ 28 VII.4 Bloodspots ______________________________________________________ 29 VIII Discussion ________________________________________________________________ 34 IV Conclusion ________________________________________________________________ 36 V References _______________________________________________________________ 37 4 List of abbreviations 3OHC4 3-hydroxybutyrylcarnitine Acetyl-CoA Acetyl-coenzyme A BCS Body condition score BHBA: Β-hydroxybutyrate C2 Acetylcarnitine C3 Propionylcarnitine masl Meters above sea level NEFA: Non esterified fatty acids SNNPR: Southern Nations, Nationalities, and Peoples’ Region VFA: Volatile fatty acids VLDL: Very low density lipoprotein 5 I Abstract Ethiopia has the fifth largest cattle population in the world, with an estimated population of 59.5 million cattle compared to the estimated human population of 107.5 million. Seventy percent of the rural households make a living from livestock farming, mainly pastoral nomadism, from which it can be concluded that livestock farming is of great economic and social importance in the countryside. Due to the lack of pasture management, there is overgrazing and soil erosion, and the land still has to deal with extremely dry periods. All this has a negative effect on livestock productivity. This creates a conflict with the increasing population growth in developing countries and the additional demand for livestock products. If the nutritional status of the cattle and their corresponding deficits are identified, these shortages can be solved, which will have a positive impact on the country's livestock sector and economy. For this research we focused on the region around Arba Minch, located in Southern Nations, Nationalities, and Peoples’ Region (SNNPR). The aim of this research was to evaluate if the approach can indicate nutritional imbalances, of dairy cattle, and the relationship with environmental factors, such as altitude and season, in the Arba Minch region. Blood samples were collected from 128 local dairy cows in 6 different districts (A/zuria, Bonke, Boreda, Chencha, Dereshe and M/abaya), along a transect extending from the lowlands to the highlands, in both seasons (dry and rainy). The body condition score and milk yield of all cows was also determined for both seasons. A spectrophotometer was used to measure the following metabolites: urea, creatinine, triglycerides and non-esterified fatty acids. Dried Serumspots was used to measure the following markers: valine, leucine, acetylcarnitine, free carnitine, propionylcarnitine and 3-hydroxybutyryl-carnitine. The research showed that there are nutritional imbalances, and that these were influenced by the examined environmental factors such as altitude, season and geographical region, in the Arba Minch region. It can concluded that the “simpler” spectrophotometric analyses can be used to estimate the nutritional status of ranging dairy cows, even when compared with more detailed metabolite analyses such as the acylcarnitine profile. Keywoords: Blood metabolites - Dairy cattle - Ethiopia - Nutritional status 6 II Samenvatting Ethiopië heeft de vijfde grootste vee populatie ter wereld, met een geschatte populatie van 59,5 miljoen stuks vee, vergeleken met de geschatte bevolkingsomvang van 107,5 miljoen mensen. Zeventig procent van de plattelandshuishoudens leeft van de veeteelt, vooral van pastoraal nomadisme, waaruit kan worden geconcludeerd dat de veeteelt van groot economisch en sociaal belang is op het platteland. Door het gebrek aan weidebeheer is er sprake van overbegrazing en bodemerosie en heeft het land nog steeds te kampen met extreem droge periodes. Dit alles heeft een negatief effect op de productiviteit van de veestapel. Dit leidt tot een conflict met de toenemende bevolkingsgroei in ontwikkelingslanden en de extra vraag naar dierlijke producten. Als de voedingstoestand van het vee en de bijbehorende tekorten worden vastgesteld, kunnen deze tekorten worden opgelost, wat een positief effect zal hebben op de veehouderijsector en -economie van het land. Voor dit onderzoek hebben we ons gericht op de regio rond Arba Minch, gelegen in de Zuidelijke Naties, Nationaliteiten en Volkerenregio (SNNPR). Het doel van dit onderzoek was om te evalueren of de aanpak kan wijzen op een onevenwichtige voeding van melkvee en de relatie met omgevingsfactoren, zoals hoogte en seizoen, in de Arba Minch regio. Van 128 lokale melkkoeien in 6 verschillende districten (A/Zurië, Bonke, Boreda, Chencha, Dereshe en M/abaya) werden in beide seizoenen (droog en regenachtig) bloedmonsters genomen langs een doorsnede die zich uitstrekt van de laaglanden tot de hooglanden. De body condition score en de melkopbrengst van alle koeien werd ook bepaald voor beide seizoenen. Een spectrofotometer werd gebruikt om de volgende metabolieten