Exogenous Enzymes as Feed Additives in Ruminants

Description

This book addresses a global issue of increasing high quality food from ruminant animals while reducing their impacts on the environment. However, one of the main constraints to livestock development and the underlying cause of the low productivity in many developing countries is inadequate nutrition associated with inefficient utilization of forages and fibrous feed resources. In many countries, fibrous feed makes up the bulk of available feed resource base, which is characterized by scarcity and fluctuating supply in the quantity and quality of feed resources, nutrient imbalance as seen in many native pastures, grasslands and crop residues-based feeding systems with limited use of commercial concentrate feeds such as soybean, cottonseed and groundnut meals, etc. Furthermore, the production of methane, an important greenhouse gas (GHG), from ruminants fed highly fibrous diets such as straws and stover is higher than those animals fed better quality forages or concentrate diets. Recent research shows that supplementing livestock diets with exogenous fibre degrading enzymes can improve feed utilization by enhancing intake, fibre degradation in the rumen and overall digestibility of fibrous feeds which in turn leads to improved animal performance, farmers’ income, and a reduction in GHG emissions. The book editors would like to acknowledge the Joint FAO/IAEA Division of Nuclear Techniques in Food and Agriculture for funding part of the studies that make up some of these chapters and were part of the final reports of a coordinated research project financed by IAEA. Contents Yeast as a Source of Exogenous Enzymes in Ruminant Feeding 1 Introduction 2 Composition of Yeast Culture 3 Yeasts as a Source of Exogenous Enzymes 4 Production of Enzymes from Yeast 5 Yeast Enzymes and Feed Utilization 5.1 Dietary Fibre Utilization 5.2 Ruminal Fermentation Characteristics 5.3 Microbial Protein Synthesis 5.4 Milk Production, Composition and Quality 5.5 Growth Performance 5.6 Meat Quality 6 Source of Dietary Lipid/Microbial Lipid 7 Means of Counteracting the Negative Effects of Mycotoxins 8 Conclusions References Yeast Culture and Direct-Fed Microbes: Modes of Action and Beneficial Applications in Ruminants 1 Introduction 2 Mechanism of Action of Yeast Culture and Direct-Fed Microbes 2.1 Mechanism of Action of Yeast Culture 2.2 Mechanism of Action of Direct-Fed Microbes 3 Beneficial Applications of Yeast Culture and Direct-Fed Microbes 3.1 Effects of Yeast Culture and Direct-Fed Microbes on Animal Performance 3.1.1 Effect on Growth 3.1.2 Effect on Intake and Lactation Yield 3.2 Effects on Rumen Fermentation 3.2.1 Effects of YC 3.2.2 Effects of DFM 3.3 Effects on Rumen Microbiota 3.3.1 Effects of YC 3.3.2 Effects of DFMs 3.4 Beneficial Effects of Yeast Culture and Direct-Fed Microbes on Host Immunomodulation 3.4.1 Effects of YC 3.4.2 Effects of DFMs 4 Conclusion and Prospects References Effects of Exogenous Enzymes on the Nutritive Value of Some Fibrous Forage in Ruminant 1 Introduction 2 Definition of Exogenous Enzymes 3 Sources of Exogenous Enzymes 4 Roles of Exogenous Enzymes in Improving Nutritive Value of Animal Feeds 5 Impact of Exogenous Enzymes 5.1 Fermentation of Fibrous Feeds 5.2 Nutrient Digestibility 5.3 Ruminal Degradability and Gas Production 5.4 Nitrogen Balance and Microbial Protein Synthesis 5.5 Milk Production, Composition and Quality 5.6 Growth Performance and Meat Quality 6 Conclusions References Exogenous Fibrolytic Enzymes: For the Better Utilization of Guinea Grass and Rice Straw as Ruminant Feeds 1 Introduction 2 Material and Methods 2.1 Location and Ethical Approval of Experiments 2.2 Animals, Management and Enzyme Treatment 2.2.1 Experiment 1 2.2.2 Experiment 2 2.3 Experimental Procedure, Measurements and Sampling 2.4 Laboratory Analyses 2.5 Calculations and Statistical Analysis 3 Results 3.1 Experiment 1 3.2 Experiment 2 4 Discussion 4.1 Experiment 1 4.2 Experiment 2 5 Conclusions References Role of Exogenous Enzymes in Feed Digestibility and Reducing the Emission Intensity of Enteric Methane Production in Ruminants 1 Introduction 2 Poor-quality Roughage and its Degradation by Ruminants 3 Treatment of Poor-Quality Roughages 3.1 Exogenous Fibrolytic Enzymes 3.2 Exogenous Fibrolytic Enzymes in the Nutrition of Ruminants 3.3 Exogenous Fibrolytic Enzymes Research Techniques 4 Sustainable Animal Production 4.1 Ruminal Digestion and Methane Production 4.2 Constraints to Fermentation of Fibrous Feed and Its Utilization 4.3 Exogenous Enzymes in Ruminant Nutrition 4.4 Factors Affecting Enzyme Efficacy in Ruminants 4.5 Enzyme–Substrate Preparation and Interaction Period Prior to Feeding 4.6 Enteric Methane Mitigation Strategies and the Role of Enzyme to Reduce Methane Emission Intensity References Inclusion of Exogenous Fibrolytic Enzymes in the Diets of Dairy Cows and Ewes: Effect on Milk Yield and Milk Composition 1 Introduction 1.1 Uses of Enzymes in Ruminants 2 Materials and Methods 2.1 Search Strategy and Selection Criteria 2.2 Data Extraction and Analysis 3 Results 4 Discussion 5 Conclusions References Determining the Effect of Enzyme Addition to Locally Available Forages in Mongolia Using In Vitro and In Vivo Techniques 1 Introduction 2 Effect of Cellulase, Xylanase, and Their Combinations on In Vitro Gas Production (GP) and In Sacco Degradability of Wheat Straw 3 Effects of Exogenous Cellulase and Xylanase Enzyme Preparations on Feed Intake, Nutrient Digestibility, Growth, and Economics of Rearing Mongolian Lamb 3.1 Feed Intake and Digestibility 3.2 Growth Performance and Feed Efficiency 3.3 Economic Evaluation 4 Conclusions References Fungi as a Source of Exogenous Enzymes in Ruminant Feeding 1 Introduction 2 Exogenous Enzymes Produced by Fungi and Their Actions 3 Exogenous Fungal Enzymes and Feed Utilization 3.1 Feed Intake 3.2 Digestibility 4 Chemical Pretreatment and/or Treatment 5 Ruminal Volatile Fatty Acids 6 Ruminal NH3-N Concentration 7 Microbial Protein Synthesis 8 Milk Production and Composition 9 Growth Performance and Meat Quality 10 Other Benefits of Fungal Enzymes 11 Conclusions References Dietary Inclusion of Exogenous Fibrolytic Enzyme to Enhance Fibrous Feed Utilization by Goats and Cattle in Southern China 1 Introduction 2 In Vitro Screening of Exogenous Fibrolytic Enzymes 2.1 Materials and Methods 2.1.1 Crop Straws, Grasses, and Enzymes 2.1.2 In Vitro Gas Production and Sampling 2.2 Results and Discussion 2.2.1 Gas Production Parameters 2.2.2 Dry Matter Degradability, Neutral Detergent Fiber Degradability, or Methane Production 2.2.3 pH Value and CH4 Production 2.2.4 NH3-N Concentration and Volatile Fatty Acid Profiles 2.3 Conclusion 3 In Vivo Evaluation of Exogenous Fibrolytic Enzyme in Goat And Cattle Feeding System 3.1 Materials and Methods 3.1.1 Evaluation of Candidate Fibrolytic Enzymes in the Feeding System of Goats 3.1.2 Evaluation of Candidate of Fibrolytic Enzymes Estimation in Cattle 3.2 Results and Discussion 3.2.1 In Goats 3.2.2 In Cattle 3.3 Conclusion References