Nutritional Characteristics of Sorghums from Queensland and New South Wales for Chicken Meat Production

Foreword 5 Acknowledgments 6 Abbreviations 7 Contents 8 Tables 10 Figures 12 Executive Summary 13 What the report is about 13 Why the research is important 13 Who the research is targeted at 13 Background 13 Aims/objectives 13 Methods used 14 Results/key findings 14 Implications for relevant stakeholders 16 Industry nutritionists 16 Sorghum breeders 17 Recommendations 17 1. Introduction 19 1.1 Historical view 19 1.2 Other toxins 19 1.3 Condensed tannin (CT) determination 19 1.4 Condensed tannins and drought 20 1.5 Research benefit 20 1.6 Chicken industry 20 1.7 Objectives 21 2. Grain sampling and chemical composition 22 2.1 Introduction 22 2.2 Materials and Methods 23 2.2.1 Collection periods 23 2.2.2 Grains types and amounts supplied 23 2.2.3 Grain samples evaluated 23 2.2.4 Grain testing 23 2.2.5 Analytical methods 24 2.3 Results and Discussion 24 26 3. Bioassays: Apparent metabolisable energy content and digestibility determinations for amino acids, starch and condensed tannins 31 3.1 Introduction 31 3.2 Materials and Methods 31 3.2.1 PGLP method for Apparent Metabolisable Energy (AME) used for 2004 grains 31 AME–adaptation period 32 AME-diets 32 3.2.2 Comparison of PGLP and PRDC methods for Apparent Metabolisable Energy (AME) determinations 32 3.2.3 PRDC method for Apparent Metabolisable Energy (AME) used for 2005 samples 33 3.2.4 Ileal digestible amino acid, nitrogen, starch and condensed tannins 33 Ileal digestibility – animals and housing 33 Ileal Digestibility – diets 33 Ileal Digestibility – digesta collection and analyses 33 3.3 Results and Discussions 34 3.3.1 PGLP method for Apparent Metabolisable Energy (AME) used for 2004 grains 34 3.3.2 Comparison of PGLP and PRDC methods for Apparent Metabolisable Energy (AME) determination 34 3.3.3 PRDC method for Apparent Metabolisable Energy (AME) used for 2005 grains 34 3.3.4 Ileal digestible amino acid, nitrogen, starch and condensed tannins: Associations with AME 35 3.3.5 The digestion of condensed tannins: Implications on nutrients digestibility 41 4. Metabolism 44 4.1 Experiment 1 – Pilot trial evaluating chicken meat diets using different sorghums from 2004 harvest in various regions of Qld and NSW 44 4.1.1 Introduction 44 4.1.2 Materials and Methods 44 Poultry house and measurements 44 Animals and diets 45 Experimental design 46 Ethical considerations 46 1.1.3 48 4.1.3 Results and Discussion 49 Bird performance 49 Relationships between grain AME intake, live weight gain and feed conversion ratio 51 4.2 Experiment 2 – Pilot trial evaluating different sorghums from Qld and NSW regions collected during 2005 harvest in chicken meat diets 55 4.2.1 Introduction 55 4.2.2 Materials and Methods 55 Poultry house, measurements, animals and diets 55 Experimental design 56 Additional treatments 56 4.2.3 Results and Discussions 59 Bird performance 59 Broiler performance comparison of pilot studies conducted on sorghum grains from the 2004 and 2005 harvest 63 Phytase pilot study – phytase addition 65 4.3 Experiment 3 – Pilot trial examining the effect of adding phytase, xylanase and cystine on broiler performance when offered selected sorghum grains 65 4.3.1 Introduction 65 4.3.2 Materials and Methods 66 Dietary treatments with added phytase and cystine 69 4.3.3 Results and Discussions 69 Bird performance 69 5. Broiler floor pens, semi-commercial growth experiments 71 5.1 Experiment 1 – Semi-commercial evaluation of broiler performance using sorghum grains from the 2004 harvest in Qld and NSW (conducted September – October 2005) 71 5.1.1 Introduction 71 5.1.2 Materials and Methods 71 Poultry house and measurements 71 Animals and diets 72 Experimental design 72 Ethical considerations 73 5.1.3 Results and Discussions 73 Bird performance 73 5.2 Experiment 2 – Semi-commercial evaluation of broiler performance using sorghum grains from the 2005 harvest in Qld and NSW (Conducted in March-May 2007) 78 5.2.1 Introduction 78 5.2.2 Materials and Methods 78 Poultry house and measurements 78 Animals and diets 79 Details of dietary feeding strategies used 79 Experimental design 80 5.2.3 Results and Discussions 83 Bird performance in a semi-commercial floor pen experiment 83 Feeding strategies to improve sorghum grain energy utilisation 86 Influence of sorghum condensed tannins and phenolics on chicken gut microflora development 86 Effect of adding phytase to sorghum-based diets 87 6. Conclusions and Implications 88 References 92