<p>A well-functioning digestive tract is key to a sustainable poultry production. Significant progress in our understanding of the digestive tract functionality has allowed for further improvements, and will continue to do so. Feed intake is a prerequisite for a high performance, where feed particle size is a key element. Although crop retention would potentially improve the digestion process, the practice of ad libitum feeding does not fully stimulate to its maximal use. The gizzard plays a very important role due to its very effective fine grinding and its role as a feed-flow regulator, but structural components need to be included in the diet. As material passes into the relatively short small intestine, it is remarkably quickly digested and absorbed. Fermentation in the caeca may contribute to some energy for the bird, but its major role seems to be water reabsorption, including from urine being refluxed into the caeca from the cloaca.</p>

<p>A feed formulation program is used to determine a compound feed that meets all of its nutritional requirements and is at the lowest possible cost (least cost). This chapter addresses current challenges facing feed formulation programs, including the need to account for sustainability issues as well as the increasing range and volume of high-quality data on feedstuff composition and effects on poultry growth. The chapter discusses solutions such as tools for importing new data into the formulation database, developing linear and non-linear optimizers to handle a greater range and volume of data and the role of artificial intelligence (AI) in future feed formulation.</p>

<p>Synthetic biology is an evolving area that can advance poultry science and production in achieving a more sustainable future. This chapter outlines multidisciplinary studies of synthetic biology to solve pressing problems within the poultry industry. It introduces state of art tools in synthetic biology and highlights recent advances and examples of practical implementation. The chapter reviews syntheses of proteins including enzymes by bacterial, fungal, and plant systems. It also covers application of synthesis biology to produce alternative proteins, nutrient supplements, antimicrobial peptides, and prebiotics for poultry feed. The chapter also reviews use of synthetic biology in waste valorization.</p>

<p>To meet the global demand poultry meat, poultry should be produced efficiently and sustainably. Feed constitutes 70% of the cost of poultry production, meaning improvements in feed efficiency would be beneficial to producers, consumers and the environment. Feed conversion ratio (FCR) is an economic trait preferred by producers because it is directly related to profitability. Different combinations of feed intake and body weight gain can provide the same FCR value and may have the same economic outcome but with different underlying biological causes. Residual feed intake (RFI) breaks down feed efficiency into efficiencies of feed intake for maintenance and growth, respectively. Feed efficiency is affected by ambient factors, animal factors and output factors and is an aggregate of several complex traits with several interacting components. Identification of a major driver, e.g. reduction in maintenance requirement, efficiency of digestion, efficiency of protein retention and efficiency of growth can significantly improve the trait.</p>

Feed and water efficiency are two vital economic and agricultural traits. Selection for phenotypic feed efficiency has tremendously improved livestock productivity over the past 50 years. However, there have been a number of undesirable changes in the regulation of energy homeostasis and probably water balance associated with this success. Feed and water efficiency encompasses complex mechanisms regulating feed and water intake, energy expenditure, water retention and excretion, and intermediary metabolism related to nutrient and water utilization and partition. Knowledge of these should be used to guide more effective selection. This chapter focuses first on feed intake regulation, offering a review of current understanding of both central feed intake regulation and peripheral and hormonal regulation. It then turns to the issue of the regulation of water homeostasis. It aims to facilitate further progress by asking new questions which may help in developing mechanisms-based strategies to improve both feed and water efficiency.

Dietary amino acids are central to optimizing growth performance, meat yield, and egg production of poultry. This chapter addresses amino acid digestibility coefficients for feed ingredients, digestible amino acid requirements of poultry based on production efficiency, and the role of supplementation of crystalline amino acids on nitrogen balance and ammonia output of poultry. In addition, knowledge gaps in the scientific literature related to amino acid responses of poultry will be discussed.

<p>Corn Fermented Protein (CFP) is the first commercially viable new source of high level (>50%), high quality vegetable protein, developed in the past twenty years and available for feeding to livestock, aquaculture, and companion animals. The protein product is derived from the sustainable fuel bioethanol production process and as a derivative of an industrial process is not in direct competition with food production. CFP has a low carbon index compared with a range of traditional protein products. This chapter describes the application of corn fermented protein in feed formulations for poultry.</p>

<p>Successful inclusion of black soldier fly larvae meal (BSFLM) in the diet of broilers and laying hens requires a precise determination of its nutritional value. These issues are discussed in the first part of this chapter together with the current understanding of amino acid content, amino acid digestibility and metabolizable energy of BSFLM. The chapter continues with an overview of the effects of dietary inclusion of different types of BSFLM on the performance and health of broilers and laying hens. The chapter concludes with an assessment of the current use of insects as feed and the future prospects of these promising alternative protein sources in poultry feed.</p>

This chapter reviews the current status of research on feed enzymes with an emphasis on identifying the key challenges researchers face in terms of current trends in enzyme development, mechanism(s) of action and enzyme efficacy. It also addresses new research directions and the development of consensus protocol and/or research approaches to prevent potential duplication of effort and to aid coordinated research and collaboration. Sections cover the key drawbacks and opportunities in the application of phytase, non-starch polysaccharides (NSP) and NSP enzymes, β-mannanase, supplemental α-amylase and protease, with a focus on achieving effective use of feed ingredients and more sustainable production of poultry meat.

<p>The purpose of this chapter is to appraise the current work done on the use of the yellow mealworm (Tenebrio molitor) as an alternative and sustainable protein source in poultry diets. The incorporation of insects in animal diets is regarded as an interesting topic in animal nutrition. Their popularity is expected to outstrip the current conventional feed ingredients globally. Based on nutritional analysis, yellow mealworm larvae are comparable to conventional poultry protein sources. Hence, they are widely documented as the most appropriate substitute for soybean meal and fishmeal as they have a similar influence on growth performance without having a negative impact on the carcass, meat quality, or egg quality. Therefore, this chapter will discuss the opportunity for using yellow mealworm larvae as a protein source in poultry diets. The nutritional and environmental benefits, processing and storge, and effects of Tenebrio molitor on poultry productivity are discussed.</p>

In this chapter nutritional modulation of immune function, with specific focus on research work from the year 2000 to present, is outlined with respect to immune responsiveness and disease resistance. In order to assess immune enhancement, suppression, and balance, independent sections for vitamins (i.e., carotenoids and vitamin E), minerals (i.e., selenium and zinc), and amino acids (i.e., arginine and threonine) are presented. Further, consideration of other nutrients is given (e.g., vitamin D, manganese, and copper). In addition to nutrients, sections in this chapter also are concerned with the ingredients on immune modulation (i.e., fats, oils, wheat, rye, insect meal, algae meal, and alternatively processed oilseeds). A section on in ovo manipulation of embryo and subsequent chick immunity is presented. Studies assessing few immune parameters versus those assessing overall immune balance in the presence of challenges are discussed.

Poultry producers have been cautious in the application of probiotics, due to mixed experiences of their effectiveness and lack of knowledge regarding the scientific basis for their modes of action. Prebiotics have been more readily accepted because they can be added without any significant change to traditional practices. Recent research has increased our knowledge of the effects of both types of treatment, their possible modes of action, and the strengths and limitations of their use. We are beginning to understand why some products may give variable outcomes and what may be done to further validate the performance of existing products and develop a new generation of more reliable and effective probiotics and prebiotics.

Soya bean and canola meal are the conventional ingredients used to provide protein in poultry feed. However, they are relatively expensive and must be imported to many poultry-producing areas. Developing alternative protein sources for poultry nutrition will reduce the pressure on these key protein sources, as well as promote the development and sustainability of the poultry industry. In this chapter, we first review the supply of conventional protein sources for poultry, and then consider the range of alternative protein sources that might be developed, including grain by-products, oil seed and fruit by-products, pulses, algae, duckweed and certain animal protein sources. We consider how birds respond to diets containing alternative protein sources, and provide recommendations for improving the nutritive value of these alternative sources.

<p>The supplementation of exogenous enzymes in diets is a common practice in the poultry industry. Different enzymes are used to target specific substrates: phytase acts on phytate, protease acts on proteins of peptides, xylanase acts on arabinoxylan, and amylase acts on starch. The utilization of these enzymes results in the release of target substrate hydrolysis endproducts, leading to enhanced digestibility and improved growth performance. Moreover, the introduction of these enzymes has facilitated the inclusion of various feed ingredients containing anti-nutritional factors in poultry diets, thereby expanding the range of available options and reducing feed costs. Despite their different modes of action and substrates, the use of multiple enzymes concurrently has a potential for synergistic or additive effects. This chapter provides a review of the possible modes of action of these enzymes, as well as recent studies investigating the effects of using these enzymes individually and in combination for broiler chickens.</p>

<p>This chapter describes advances in understanding and improving the use of macro-minerals in poultry with a particular focus on phosphorus (P). The chapter begins by outlining the challenges to optimising mineral nutrition in poultry, covering the characterisation of the P value in feed ingredients and factors that affect P availability. Next a section on case studies is explored, including a meta-analysis for assessing the P value of a diet and a model where the P and calcium (Ca) quantities required for maintenance and growth are aggregated to determine the overall needs of the animals. Finally, future trends are discussed, covering precision feeding for sustainability, the potential for compensatory mechanisms and genetic determinism, the balance between Ca and P in laying hens, and a digestible Ca system.</p>

<p>The global poultry industry tends to depend on a limited number of feed ingredients, which face a number of environmental and other problems. The objective of this chapter is to examine emerging, alternative ingredients for potential use locally or for development into global protein sources for the poultry industry.</p>

Antibiotics play a central role in human health, and the sensitivity of bacteria to these compounds is a natural resource that must be husbanded to keep from losing their effectiveness from increasing antibiotic resistance in the environment. This chapter places the use of antibiotics in poultry production in its historical context to understand the benefits that antibiotics have conferred on animal production to date. The chapter considers past, present and future use of antibiotics, focusing on the use of bacteriocins and phytochemicals.

Systematic evaluation of each stage of the feed manufacturing has the potential to identify opportunities for improvement in manufacturing efficiency and reduced nutrient variation in finished feed, ultimately resulting in lower cost sustainable poultry production. This chapter examines the role of automation technology in composing and delivering feed, and addresses the issues of batching, mixing and pelleting feed as well as means of assessing feed quality. The chapter suggests some future developments in the use of technology in poultry nutrition and directs the reader to further reading in this area.

Natural and artificial contaminants in poultry feed may result in deteriorated feed quality, reduced performance and increased incidence of disease in poultry, ultimately leading to a significant economic loss for producers. Moreover, since poultry are raised to produce meat and eggs for human consumption, contaminants in poultry feed may also pose risks to human health. This chapter focuses on those contaminants considered to pose the most significant risk to poultry and human health: mycotoxins, dioxins and bacterial pathogens. Each section will discuss the negative effects of these factors as well as possible control measures that may be implemented to reduce feed contamination and secure feed and food safety.

Hen nutrition must address a number of different goals, including maximizing egg production, maintaining egg quality, extending the laying cycle and ensuring hen health and welfare. This chapter focuses on the role of nutrition in optimizing energy intake, egg size and egg weight. It reviews the different nutritional requirements hens have in their pre-laying and laying phases; discusses how feed consumption can be controlled; and then reviews the effects of energy concentration, dietary lipids, dietary proteins and amino acids on egg weight. It also offers a discussion of how the inclusion of cereals and alternative protein sources in the diet can affect egg characteristics.

<p>Knowledge of amino acid formulation minimum constraints in the nutrient matrix are pivotal in order to allow for formulation flexibility, and subsequent broiler productivity at minimum nitrogen supply. Four key amino acid minimums that beg for more research are: arginine, glycine and serine, histidine, and phenylalanine and tyrosine. In this chapter the former have been reviewed.</p>

<p>Probiotics and prebiotics boost poultry gut health and immunity. This chapter discusses current research and practical applications of these microbial-based supplements for chicken production. The chicken industry has struggled recently with gastrointestinal disorders, poor meal absorption, and viral infections. Probiotics and prebiotics, non-digestible food additives that boost gut microorganisms, may help. This chapter book explains probiotic and prebiotic interactions with avian gut flora. Probiotics and prebiotics impact poultry intestine bacteria balance, architecture, nutrient digestion, and immune control. The chapter also discusses issues in using probiotics and prebiotics. The chapter aims to provide a comprehensive reference for researchers, poultry nutritionists, veterinarians, and industry professionals interested in the potential benefits and practical applications of probiotics and prebiotics in poultry.</p>

<p>This chapter describes the main nutritional characteristics of algae and the current knowledge on their effects in poultry production with consideration to their impacts on animal health, growth performance, and product quality (eggs and meat). The chemical and nutritional value of algae is explored, along with extraction methods and the benefits of algae to animals. The authors then describe their impacts on laying hen production, covering egg productivity, quality and composition, as well as hens' health. Finally algae's effect on broiler chicken production is reviewed, covering growth performance, meat production and quality, and broiler health.</p>

The poultry industry has witnessed remarkable advancements in recent years. This chapter provides a discussion of the advances and future directions in the poultry feeding. Advancements include defining nutrient requirements, composition and ingredient quality, better feed formulation and the advent of additives. It also discusses the developments in feed processing and phase feeding. Future directions include sustainability, ingredient quality, antibiotic-free nutrition, crystalline and synthetic amino acids, feed enzymes, chick nutrition and growth models. Optimal feed processing and the related hygiene practices are discussed briefly. The chapter then discusses future trends in poultry feeding. The chapter concludes with a section dedicated to further information on these topics, in order for the readers to expand their knowledge.

Hen nutrition must address a number of different goals including maximising egg production, maintaining egg quality, extending the laying cycle and ensuring hen health and welfare. This chapter focuses on the dietary influences on eggshell quality and bone health. It looks first at the role of phosphorus and calcium in the diet. It then goes on to review other nutritional factors such as fatty acids, vitamins, magnesium and trace elements. After a review of dietary influences on egg yolk coloration, the chapter concludes by discussing the ways nutrition can promote hen health in such areas as the prevention of hepatic steatosis, osteoporosis, keel bone disorders and feather picking.