Nâng cao hiệu quả sử dụng bauhinia acuminate trong chăn nuôi dê ở lào

HUE UNIVERSITY UNIVERSITY OF AGRICULTURE AND FORESTRY PHONEVILAY SILIVONG IMPROVED UTILISATION OF BAUHINIA ACUMINATA FOR GOAT PRODUCTION IN LAO PDR DOCTOR OF PHILOSOPHY IN ANIMAL SCIENCES HUE, 2020 HUE UNIVERSITY UNIVERSITY OF AGRICULTURE AND FORESTRY PHONEVILAY SILIVONG IMPROVED UTILISATION OF BAUHINIA ACUMINATA FOR GOAT PRODUCTION IN LAO PDR SPECIALIZATION: ANIMAL SCIENCES CODE: 9620105 DOCTOR OF PHILOSOPHY IN ANIMAL SCIENCES SUPERVISOR 1: ASSOC.PROF NGUYEN HUU VAN SUPERVISOR 2: DR DUONG THANH HAI HUE, 2020 GUARANTEE I hereby guarantee that scientific work in this thesis is mine All results described in this thesis are righteous and objective They have been published in Journal of Livestock Research for Rural Development (LRRD) http://www.lrrd.org Hue University, 2020 Phonevilay Silivong, PhD student ACKNOWLEDGEMENTS The research in this PhD thesis was conducted at the farm and laboratory of Department of Animal Science, Faculty of Agriculture and Forest Resource, Souphanouvong University, in Luangprabang Province, Lao PDR with supported from Mekong Basin Animal Research Network (MEKARN II) project for funding this theses research and the scholarship for the PhD degree I am grateful for the support from all of those people and institutions I am greatly indebted to my main supervisor, Associate Professor Nguyen Huu Van and co-supervisor, Dr Duong Thanh Hai for his mentoring and constructive advice during my studies He made me much more confident as a scientist and researcher His patience and encouragement during my illness and positive criticism made it possible to accomplish this work My special thanks to Professor Thomas Reg Preston and Professor Dr Ron Leng, my teacher and adviser, for all your valuable guidance and support during the study I would also like to extend sincere thanks to Professor Dr Ewadle, International Coordinator MEKARN II project; Dr Vanthong Phengvichith, National Agriculture and Forestry Researcher Institute (NAFRI), Lao PDR; Dr Kieu Borin, MEKARN II regional coordinator for their facilitation, help and support to the whole course Professors, lecturers and assistant lecturers in Hue University of Agriculture and Forestry and MEKARN II program, for giving me care and useful knowledge Warm thanks are extended to my father, Mr Souk Silivong for his great help and support My mother, Ms Khampoun Silivong for her assistance and encouragement, my older brothers and sister Mrs Kesone Silivong, Mr Vone Silivong, Mr Sonexay Silivong and younger sister Mrs Bounmee Silivong for their supported and encouragement; to my wife, Mrs Souksadar Vongyalud and my son Phetsamone Silivong and my daughter Souphaphone Silivong for their love I would like to warmly thank Mr Khamlek and Mr Phonesavath, and Mr Siphone, my analysis assistants and my colleagues in the Department of Animal Science, Faculty of Agriculture and Forest Resource, Souphanouvong University All of my friends in the PhD program 2017-2020 from the three countries: Laos, Vietnam and Cambodia, for sharing the culture, friendship and creating a warm atmosphere throughout the time of the course I would like to thanks all the people who contributed to this study ABSTRACTS This study was aimed at the utilization of locally available feed resources for increasing growth performance and reducing enteric methane emissions from goats in Lao PDR Five experiments (two in vitro and three in vivo) were carried out and presented in four chapters of this dissertation Experiment evaluated the effect on methane production from leaves of Bauhinia acuminata and Guazuma ulmifolia of an increasing level of water spinach as source of soluble protein Experiment and were studied the effects of water spinach and biochar on enteric methane emissions and growth performance in local goats fed Bauhinia acuminata and molasses, or cassava root chip, as the basal diet Experiment aimed to determine the effect of different protein sources (cassava foliage or water spinach) with or without of brewers’ grain (5% of diet DM)) on feed intake, digestibility, N balance and growth performance of local goats Experiment was to determine the effect of biochar and leaf meal from sweet and bitter cassava leaves, on methane production in an in vitro incubation of Bauhinia acuminata and water spinach as basal substrate The main findings of the study were that: (1) Goats fed Bauhinia acuminata responded with improved diet digestibility, N retention and growth rate when the Bauhinia acuminata was supplemented with water spinach; (2) However an important negative effect was that the improvement in diet digestibility by supplementation with water spinach led to increases in methane production per unit diet DM digested; (3) Supplementing Bauhinia acuminata foliage with leaves from a bitter variety of cassava reduced the in vitro production of methane when compared with supplementation by leaves from a sweet variety of cassava; (4) Ensiled brewers’ grains fed as an additive (5% as DM) to a diet of Bauhinia acuminata improved the digestibility, N retention and growth rate of goats The degree of improvement was greater when the Bauhinia acuminata was supplemented with cassava foliage instead of water spinach; (5) Biochar fed at 1% of a diet of Bauhinia acuminata and cassava foliage was as effective as brewers’ grains in improving the growth rate of the goats The results of this study indicated that supplementation of foliage from water spinach or cassava improved growth of local goats fed Bauhinia acuminata as basal diet HCN present in the leaves of cassava could be the reason for the reduction in methane emission Ensiled brewers’ grains and biochar fed to goats as additives probably act as “prebiotics” to improve growth performance and assist in detoxification in the animal Key words: N-balance, protein solubility, bauhinia, water spinach, solubility Nbalance, rumen ammonia, biochar, prebiotics, HCN DEDICATION To my parents, my wife Souksadar Vongyalud, my son (Phetsamone Silivong) and daughter (Souphaphone Silivong) To: My country (Lao PDR) TABLE OF CONTENT LIST OF TABLES CHAPTER LITERATURE REVIEW LIST OF FIGURES CHAPTER LITERATURE REVIEW LIST OF ABBREVIATIONS, SYMBOLS AND EQUIVALENTS ADF Acid detergent fibre ANOVA Analysis of variance AOAC Association of Official Analytical Chemists BW Body weight BG Brewers’ grains BC Biochar CF Cassava foliage CR Cassava root CF Crude fibre CH4 Methane CO2 Carbon dioxide CP Crude protein CT Condensed tannins CLM Cassava leaf meal DM Dry matter DMI Dry matter intake FCR Feed conversion ratio FMD Foot and Mouth Disease GDP Gross Domestic Product GHG Green House Gas Hectare Kg Kilogram HCN Hydrogen cyanide HS Hemorrhagic Septicemia LW Live weight Mekarn Mekong basin animal research network N Nitrogen NDF Neutral detergent fibre NH3 Ammonia NPN None protein nitrogen OM Organic matter pH Percentage of Hydrogen Ion Prob/P Probability PPM Part per million RCBD Randomized complete block design SE Asia South East Asia SEM Standard error of the mean Sida-SAREC Swedish international development cooperation agency Department for research cooperation TDN Total Digestible Nutrition VFA Volatile Fatty Acid WS Water spinach INTRODUCTION PROBLEM STATEMENT Laos is located in the central part of the Indochinese Peninsula It is an inland state surrounded by China, Vietnam, Cambodia, Thailand and Myanmar Lao PDR has a total land area of 236,800 km The agricultural land is limited to around 4% of total, consisting of 18 provinces/cities comprising 148 districts Laos population has 7,028,094 people and is equivalent to 0.09% of the total world population Laos has a distinct rainy season from May to November, followed by a dry season from December to April Local tradition holds that there are three seasons (rainy, cold and hot) as the latter two months of the climatologically defined dry season are noticeably hotter than the earlier four months Goats are increasingly important for subsistence food production with over 90% of the global goat population found in developing countries (Glimp, 1995; FAO, 2005; World Bank, 2013) As goats produce several livestock products with lower inputs than cattle and buffalo, smallholder goat farmers in developing countries, particularly in Asia and Africa, have increasingly been recruited to goat raising, with goats described as an ‘entry point’ on the ‘pathway from poverty’ Goats are considered more easily managed than cattle, especially by resource poor farmers, including women Goat raising offers households nutritional benefits as meat protein for hunger alleviation, enhanced livelihoods from animal trading income, more effective utilisation of family labour, and increased livelihood stability and resilience in rural communities due to more self-reliance (FAO, 2005; World Bank, 2013) In Southeast Asia, goats have been of increasing importance, particularly in countries with large Islamic populations, including Indonesia, Malaysia, and parts of the Philippines and Thailand However, in recent years, increasing demand for consumption of goat meat in Vietnam and China has created opportunities for increasing production in the Lao People’s Democratic Republic (Laos, henceforth) Currently, the government of Laos is attempting to obtain an average meat supply for local consumption of 60kg/capita/year, plus increased meat exports to a value of USD 50 million by 2020 (FAO, 2005) In Laos, goat production is traditionally extensive with low inputs, and subsequently low outputs (Kounnavongsa et al., 2010) Four major goat management systems have been described, including: free range; semi-free range; semi-rotational grazing; and permanent grazing with or without tethering Free range is the most commonly observed system, although semi-free range can be found in areas where cropping predominates (Kounnavongsa et al., 2010; Phengvichith and Preston, 2011) In most systems, goats are herded back to the village and kept in small hutches overnight for protection, although housing is only considered beneficial if it is kept clean (Phengsavanh, 2003) The system used by an individual farmer will depend upon feed and labour availability plus local community agreements, particularly related to cropping and use of common grazing areas (Kounnavongsa et al., 2010; Phengvichith and Preston, 2011) Typically, Lao goat herds consist of 3-10 animals (Kounnavongsa et al., 2010; Phengvichith and Preston, 2011), although there are some recent examples of developing herds with as many as 200 animals raised on semi- and fullycommercial farms Approximately 551,153 goats were recorded in Laos in the 2016 agricultural census (DLF, 2016) This number is likely to be underestimated, as it is widely considered to have been increasing rapidly due to recent expanding regional demand for goat meat, particularly from Vietnam, with estimates that between 2,0003,000 goats per month are being exported Increasing demand for consumption of goat meat in Laos and neighbouring Vietnam and China, is providing opportunities for smallholder farmers to increase productivity and has led to the development of semi to full commercial production systems to capitalise on the growth in this emerging livestock sector, particularly if biosecure transboundary trade can be enhanced (Stur et al., 2002; Windsor, 2011; Nampanya et al., 2015) However, introducing goats and expanding small goat herds where smallholders and potential commercial operators have limited experience of small ruminants can be exceedingly challenging In recent years, many international development agencies have promoted smallholder goatraising programs with distribution of goats to untrained farmers, often accompanied by severe mortality and morbidity problems (Windsor et al., 2017) In developing improved systems for feeding livestock, account must also be taken of the impacts on the environment It is estimated that livestock presently account for some 18% of greenhouses gases which cause global warming (Steinfeld et al., 2006) Enteric methane from fermentative rumen digestion is the main source of these emissions There is an urgent need to develop ways of reducing methane 10 The bottles were incubated at 38°C in a water bath for 24 h Table Composition of substrate (% DM basis) Sweet cassava leaves SC-Bio SC-NoBio 24 25 Bitter cassava leaves BC-Bio BC-NoBio 24 25 Biochar 1 Bauhinia leaves 60 60 60 60 Water spinach leaves 10 10 10 10 Cassava root chips 5 5 Table Ingredients of the buffer solution (g/liter) CaCl2 NaHPO4.12H2O NaCl KCl MgSO4.7H2O 0.04 9.30 0.47 0.57 0.12 NaHCO3 Cysteine 9.80 0.25 Source: Tilly and Terry (1963) Data collection and measurements Gas production was measured at intervals for 6, 12, 18 and 24h by water displacement (a calibrated recycled water bottle with the bottom removed) suspended in water so as to measure the gas production by water displacement and at the end of each incubation, the methane concentration recorded by passing the gas through a Crowcon infra-red analyser (Crowcon Instruments Ltd, UK) The residual DM in the incubation bottle was determined by filtering through cloth and drying the residue (65°C for 72 h) Solubility of the protein in the cassava leaves was determined by shaking 3g of dry leaf meal in 100 ml of M NaCl for 3h then filtering through Whatman No.4 filter paper and determining the N content of the filtrate (Whitelaw et al., 1963) Chemical analyses The leaves of cassava, Bauhinia acuminata, water spinach and residual substrate were analysed for DM, ash and N according to AOAC (1990) methods Solubility of the protein in the cassava leaves was determined by shaking 3g of dry leaf meal in 100 ml of M NaCl for 3h then filtering through Whatman No.4 filter paper and determining the N content of the filtrate (Whitelaw et al., 1963) The leaves of 112 cassava, Bauhinia acuminata, water spinach and residual substrate were analysed for DM, ash and N according to AOAC (1990) methods="_Toc315720164" Statistical analysis The data were analyzed by the general linear model option of the ANOVA program in the Minitab software (Minitab, 2014) In the model the sources of variation were: treatments, replicates and error The statistical model was: Yijk = μ + Pi + Aj + Pi*Aj+ eijk Where: Yijk is dependent variables μ is overall mean Pi is the effect of cassava leaves Aj is the effect of biochar source (P*A)ij is the interaction between source of cassava leaves and source of biochar eijk is random error RESULTS The chemical composition of substrate ingredients is presented in Table Protein solubility was lowest in Bauhinia acuminata, was lower in bitter than in sweet cassava leaves and highest in water spinach leaves Table The chemical composition of substrate ingredients (% in DM, except DM which is on fresh basis) Bauhinia leaves Bauhinia stem Sweet cassava leaves Sweet cassava petiole Bitter cassava leaves Cassava root chip Water spinach Biochar The linear increase in methane concentration in the gas with duration of the incubation (Table 4; Figures and 3) is similar to the trends observed by Outhen et al., 113 2011; Binh Phuong et al., 2011; Inthapanya et al., 2011 and Silivong and Preston, 2015 who used the same in vitro fermentation model These results indicate that there is a lag time either in the growth of organisms that ferment carbohydrate to VFA and hydrogen, and/or in the growth of those that convert hydrogen to methane Table Mean values for gas production, percentage of methane in the gas, DM digested and methane production per unit DM digested, according to source of cassava leaves (sweet SC or bitter BC) and with (Bio) or without (NoBio) biochar CL SC BC p Bio Bio p SEM NoBio Interaction SEM p 0-6 h Gas, ml 640 581 0.001 614 608 0.654 9.62 13.59 0.787 CH4, % 9.5 8.4 0.007 8.9 9.0 0.724 0.24 0.35 0.724 DM digested, % 54.9 46.4