**7. Conclusions**

The primary ingredients used in broiler poultry nutrition are limiting in SAAs in particular. Methionine and cysteine as the major SAAs, are α-amino acids which are important in animal nutrition. The recent increase in growth potentials of modern commercial broilers has been attributed to genetic improvement resulting in increased appetite and early market weight. They are more responsive to proteins (amino acids) than to energy concentration due to reduced maintenance need. Amino acids play vital nutritional and physiological roles in all livestock and must be supplied in appropriate ratios to foster protein accretion, the major objective in broiler poultry production. Nutritionally, amino acids are equivalent to proteins, warranting a shift in focus from proteins to individual amino acids.

Dietary amino acids must be in the ideal ratios for efficient use of proteins in diet formulation, maximum utilization and minimum excretion of nitrogen. Among the SAAs, methionine and cysteine are gluconeogenic and need to be balanced to circumvent the lethality associated with excess cysteine, an apparently irreplaceable amino acid. However, biosynthesis of cysteine occurs in animals and plants via the

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*Cysteine in Broiler Poultry Nutrition*

**Acknowledgements**

under short notice.

**Conflict of interest**

**Author details**

Port Harcourt, Nigeria

*DOI: http://dx.doi.org/10.5772/intechopen.97281*

proper growth and development in broiler poultry.

trans-sulfuration pathway from methionine, and its requirement is subsumed in the TSAAs requirement in poultry. Basically, cysteine is incorporated into structural proteins, and is required for normal growth. A balance in the methionine:cysteine ratio is therefore, necessary to ensure efficient utilization of the SAAs, so as to foster

We are deeply indebted to the omniscience God, the Fountain of all wisdom, who we worship and adore, for endowing and equipping us with the necessary wisdom and skills to write this chapter. We also thank our colleagues friends and wellwishers for their encouragement. Special appreciation to Joan Business Services, Azikiwe Road, Port Harcourt, Nigeria, for skillfully typesetting the manuscript

Finally, we wish to thank our wives and children, very specially, for their encouragement, and for having to bear with our apparent momentary unavailability during the preparation of the manuscript: For Nte - Ruth (wife) and Awaji-inyiemi (son); and for Gunn - Regina (wife), Ewomazino (daughter), Oghenemaro (daugh-

Department of Animal Science, Faculty of Agriculture, Rivers State University,

© 2021 The Author(s). Licensee IntechOpen. This chapter is distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/ by/3.0), which permits unrestricted use, distribution, and reproduction in any medium,

ter), and Okgariorieze (son). We love you all unconditionally.

The authors declare no conflict of interest.

Iyakutye Jacob Nte\* and Hollinshead Holly Gunn

provided the original work is properly cited.

\*Address all correspondence to: nte.iyakutye@ust.edu.ng

*Cysteine in Broiler Poultry Nutrition DOI: http://dx.doi.org/10.5772/intechopen.97281*

trans-sulfuration pathway from methionine, and its requirement is subsumed in the TSAAs requirement in poultry. Basically, cysteine is incorporated into structural proteins, and is required for normal growth. A balance in the methionine:cysteine ratio is therefore, necessary to ensure efficient utilization of the SAAs, so as to foster proper growth and development in broiler poultry.
