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Title of Thesis

Effect of low protein diets with varying energy to protein ratios supplemented with limiting amino acids on performance of broilers

Author(s)

Zahid Kamran

Institute/University/Department Details
Institute Of Animal Nutrition And Feed Technology / University Of Agriculture, Faisalabad
Session
2010
Subject
Soil Science
Number of Pages
140
Keywords (Extracted from title, table of contents and abstract of thesis)
Ratios, Broilers, Characteristics, Performance, Protein, Diets, Energy, Acids, Affecting, Effect, Limiting, Supplemented, Amino, Formulated, Varying, Low

Abstract
Two experiments were conducted to investigate the effect of low crude protein (CP) diets with increased or constant metabolizable energy to crude protein (ME:CP) ratios supplemented with limiting amino acids (AA) on the performance of broilers. Experiment 1 was conducted to study the effect of lowering dietary CP with optimum limiting AA levels on the performance of broilers from 1 to 35 days of age. Four experimental diets were formulated to have four levels of CP as 23, 22, 21 & 20% in starter phase; 22, 21, 20 & 19% in grower phase and 20, 19, 18 & 17% in finisher phase, respectively. All diets were isocaloric within a phase (2925, 3075 & 3125 kcal/kg ME for starter, grower and finisher periods, respectively). Digestible lysine was maintained at 1.10, 1.02 and 0.90% of the diet in starter, grower and finisher periods, respectively. Results showed that the dietary CP level could be reduced without harmful effects on the growth performance, body composition and carcass characteristics when supplemented with limiting AA. Experiment 2 was conducted to determine the effect of low CP diets with constant ME:CP on the performance of broilers from 1 to 35 days of age. Four experimental diets were formulated to have four levels of CP and ME, respectively, in each phase: 23, 22, 21 and 20% CP, with 3036, 2904, 2772 and 2640 kcal/kg in starter phase; 22, 21, 20 and 19% CP, with 3146, 3003, 2860 and 2717 kcal/kg in grower phase; and 20, 19, 18 and 17% CP, with 3100, 2945, 2790 and 2635 kcal/kg in finisher phase. Digestible lysine was maintained at 1.10, 1.02 and 0.90% of the diet in starter, grower and finisher periods, respectively. Results showed that chicks fed low CP diets with constant energy to protein ratio grew slower, used feed less efficiently and retained more fat than chicks fed the control diets even when standard levels of critical AA were maintained in the diets. In conclusion, reducing the dietary CP level provided substantial economic returns without affecting the performance of broilers.However, reduction of dietary CP with constant ME:CP ratio resulted in reduced broiler performance and carcass composition.

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S. No. Chapter Title of the Chapters Page Size (KB)
1 0 CONTENTS

 

iii
18 KB
2

1

INTRODUCTION

 

1
21 KB
3 2 LITERATURE REVIEW

2.1 Importance of protein
2.2 Concept of ideal protein
2.3 Effect of Low CP diets on broiler performance
References

5
163 KB
4 3 PERFORMANCE OF BROILER CHICKS FED LOW LEVELS OF DIETARY CRUDE PROTEIN 36 FROM ONE TO THIRTY-FIVE DAYS OF AGE

3.1 Abstract
3.2 Introduction
3.3 Materials and methods
3.4 Results
3.5 Discussion
3.6 Conclusions
References

36
216 KB
5 4 EFFECT OF LOW CRUDE PROTEIN DIETS WITH CONSTANT METABOLIZABLE ENERGY 79 -TO-CRUDE PROTEIN RATIO ON THE PERFORMANCE OF BROILER CHICKS FROM ONE TO THIRTY-FIVE DAYS OF AGE

4.1 Abstract
4.2 Introduction
4.3 Materials and methods
4.4 Results
4.5 Discussion
4.6 Conclusions
References

79
206 KB
6 5 SUMMARY

 

121
24 KB