1 Introduction

Poultry farming is a backbone of international agriculture, producing enormous amounts of the globe's meat and egg proteins. It is simultaneously a driver both of food security and development and of industrial and smallholder farmers. Genetic enhancement, nutrition, and management on farm have over the decades revolutionized productivity at minimal cost and environmental effect. However, in spite of that, risks of fluctuating feed costs, disease epizootics, and increasing consumer demands for sustainable and ethical production still influence the industry (Kishawy et al., 2024). Backyard poultry keeping in developing nations is critical to poverty alleviation and improvement in family diets, showcasing its social and economic significance in broader terms. As there is a growing international need for poultry products, there are more and more new means by which scientists and industry actors try to determine how they can maximize their formulation of feed in order to gain highest efficiency and sustainability (He et al., 2021).

Equilibrium in nutrition is the basis to attain maximum poultry growth, health, and performance. Adequate diet not only promotes feed conversion but also improves immune function and egg and meat quality (Beski et al., 2015). Major macronutrients such as energy and protein, and essential vitamins and minerals, maintain a chicken's metabolic and physiological functions. When the above nutrients are lacking or imbalanced, chickens can grow slower, have low feed efficiency, and be more vulnerable to disease (Barekatain et al., 2021). This has, consequently, fueled interest in precision nutrition and gut health management to maximize nutrient utilization and performance. Additionally, with the industry focus now leaning towards the production of antibiotic-free products, nutrition methods that enhance immunity naturally have become a priority.

Understanding the nutrient needs of chickens at different life stages allows more precise formulation of feeds and, in the long run, optimizes efficiency and profitability in production (Moss et al., 2021). The review herein is on the most critical dietary nutrients involved in poultry development and growth and considers feed formulation strategies that improve health, performance, and sustainability. It covers stage-specific nutrient requirements, disease protection, and quality of product and also incorporates emerging areas like other sources of protein, precision technology in feeding, and sustainable nutritional strategies. Amidst mounting environmental pressure and pressure on antibiotic resistance, poultry nutrition improvement is now more important than ever before to develop long-term sustainability into the business. Through the integration of new studies and new practice, this paper presents beneficial information on poultry nutrition that could guide farmers, scientists, and industry stakeholders on how to utilize more sustainable and efficient feeding systems.

2 Basic Nutritional Requirements of Chickens

2.1 Energy requirements and energy sources

Energy is an important constituent of a chicken’s diet which affects growth rate and overall efficiency of production. Although chickens have the capacity to automatically regulate feed consumption in relation to energy needs, commercial strains of the bird at present may not always react maximally to varying dietary energy levels. There is thus a need to design balanced diets with sufficient energy to meet maintenance needs and allow for growth in muscle and production. Grain cereals such as wheat and maize are the primary providers of energy, yet as they contain relatively small amounts of protein, they are supplemented with high-protein feed to produce a well-balanced diet (Goluch et al., 2023).

2.2 Protein and amino acid requirements and their role in growth

Amino acids and proteins are the most important feed nutrients for chicken muscle development, hormone synthesis, and enzyme activity. Broilers particularly require more protein consumption through feeding in the form of diets to maintain high growth rates and optimal feed efficiency. Optimum performance is on the basis of sharp protein formulation in feedingstuffs. Growth-promoting essential amino acids including lysine, methionine, cysteine, threonine, and tryptophan are required but normally deficient in nature-based feedingstuff components. In return, broiler producers integrate proprietary protein sources—animal and plant—to facilitate immune performance and reverse the outcome of anti-nutritional elements that lead to digestion interference as well as nutrient absorption (Elwinger et al., 2016; Xu, 2024).

2.3 Impact of minerals and trace elements on health

Trace minerals and trace elements are involved in poultry health in the formation of bones, enzyme function, and overall metabolic equilibrium. Phosphorus and calcium are particularly crucial for broiler chickens and layers, whose eggshell quality and bone development rely on these minerals. Dietary ratios must be well balanced to avoid deficiency and imbalance that will impede growth and productivity. Besides, trace minerals like iron, copper, and manganese are credited with immune function and metabolic activity. Since natural feed sources could be poorly mineralized, supplementation is necessary in order to achieve optimal poultry health and performance (Ameen et al., 2023).

2.4 Role of vitamins in growth and immune regulation

Although they are required in small quantities, vitamins are required for disease resistance and poultry development. Their identification changed poultry nutrition because it brought to light their functions in metabolism, immune protection, and overall health. Water-soluble vitamins like thiamine, riboflavin, and niacin are important in energy metabolism, whereas fat-soluble vitamins like vitamin D are essential for phosphorus and calcium absorption, which has a direct effect on bone strength and eggshell quality. Supplement vitamins are needed by the chickens to prevent nutrient deficiencies that could suppress growth and lower immunity (Barszcz et al., 2022).

2.5 Importance of water in nutrient metabolism and health maintenance

Water is not always considered a nutrient but is perhaps the most critical part of poultry diets. It facilitates digestion, assists in the transportation of nutrients, assists in the regulation of body temperature, and assists in the elimination of waste. Dehydration or restricted water consumption will cause metabolic upset, reduced feed consumption, and overall poor health in a very short period of time. There is a need to supply a uniform amount of fresh, clean water to support optimal physiological processes and poultry welfare (Classen, 2017).

3 Nutritional Requirements at Different Growth Stages

3.1 Chick stage (0~3 weeks): high energy and high protein requirements

The first weeks of a chick's life are of the most importance in their growth and overall development. Feeding at this period is key to sustaining a healthy weight, strong skeletal build, and developing the digestive system appropriately. In order for proper growth, chicks require to take in an energetic and proteinous diet. It has been proposed by studies that for optimal early growth, dietary energy intakes of 2 600 to 2 800 kcal ME/kg are optimally supplemented by a crude protein content of around 20% (Maliwan et al., 2019).

Amino acids constitute a key part of early chick nutrition. Lysine and methionine, both essential amino acids, play very important roles to play in modulating the rate of growth and the feed efficiency. Balanced feed that meets these amino acid needs can allow optimal chick growth as well as an effective immune system. Moreover, utilization of early nutrition methods-early post-hatch feeding-is applicable to ensure overall improved performance through the stimulation of early gut development and maximum nutrient uptake. Early interventions like these form the basis for future health and productivity (Table 1) (Maliwan et al., 2019; Rostichelli et al., 2020).

3.2 Growth stage (4~6 weeks): balancing protein, energy, and micronutrient needs

Nutritional focus at this stage is given to protein and energy balance, and sufficient micronutrients. This is paramount for muscle and bone development, as well as bone density, which requires proper adjustment of nutrients. Electrolyte balance with sodium and chloride levels at 0.15% and 0.23%, respectively, is required for growth and hydration (Deepak et al., 2017). Non-phytate phosphorus at approximately 0.439% is useful in mineral absorption and bone development.

Amino acid concentrations must be balanced to balance fluctuating metabolite demands. Lysine, methionine, and threonine input balancing maximizes protein deposition and muscle growth, leading to increased feed conversion and overall production efficiency (Table 2) (Rostichelli et al., 2020; An and Kong, 2024).

3.3 Fattening stage (7 weeks and beyond): strategies to improve feed utilization efficiency

Once chickens reach the fattening phase, feeding is focused on using the feed efficiently to gain as much weight as possible at the least amount of feed cost. Their protein needs by now begin decreasing a bit, with their best rate being 18% to 19%-just enough to power growth without excess. Adequate energy consumption is also still essential, as energy powers effective feed conversion. It has been established that a dietary energy intake of about 2 800 kcal ME/kg maximizes growth and feed efficiency (Navarro et al., 2023).

To achieve maximum economic efficiency, adjustment of feeding often involves lowering protein intake slightly but not changing energy intake. The ratio is in a manner that maintains maximum weight gain without overfeeding chickens to get to market-weight at the right time. Through variation in the nutrient ratio, producers get to achieve maximum feed efficiency and cut down on wastage, achieving economic as well as environmental sustainability (Table 3) (Rostichelli et al., 2020; Navarro et al., 2023).

3.4 Nutritional requirements of laying hens: adjustments during peak and late laying periods

Laying hens require exact nutritional needs which also vary for peak and late laying stages. Peak production demands more phosphorus and calcium to continue eggshell formation and overall production. Suitable levels of non-phytate phosphorus (NPP) at around 0.439% provide healthy bones and firm eggshells (Gong et al., 2024).

When hens reach the mature laying stage, energy and protein intake must be modified. The goal is to continue egg production without excessive weight gain, which negatively affects laying performance. Being in the proper balance of nutrients is essential to have consistent egg production and healthy hens throughout their productive life.

4 Strategies for Optimizing Feed Formulation

4.1 Traditional feed ingredients and alternative protein sources

Corn and soybean meal have been mainstays of chicken diets for decades, offering nutrient value for production and growth. These conventional feedstocks, however, do not necessarily yield the best-balanced broiler protein profile. For augmenting poultry nutrition, added supplemental protein can be derived from plant- or animal-based sources. Such alternatives enhance digestibility, lower levels of anti-nutritional compounds, and encourage gut health, leading to better early growth (Ajao and Olukosi, 2024). Additionally, the use of alternative proteins can also lower dependency on traditional feed ingredients, thus promoting cost savings and sustainable agriculture. Diet variety ensures that poultry are adequately fed without impacting growth rates adversely.

4.2 Precision amino acid balancing and low-protein diet strategies

Precision nutrition includes the formulation of poultry diets for specific amino acid requirements, improving efficiency and reducing environmental impact. One beneficial strategy is the formulation of low-protein diets with supplementation using crystalline amino acids so that birds receive adequate essential and non-essential amino acids (Selle et al., 2020). The manipulation of the lysine-to-metabolizable energy ratio also allows diet formulation to become more flexible, optimizing protein utilization. Precision feeding technologies take this approach a step further by modulating nutrient intake on a continuous basis to the requirements of the birds, improving feed conversion efficiencies and minimizing wastage (Bailey, 2020).

4.3 Application of feed additives

Feed additives are key to poultry nutrition improvement, which translates into better health and feed efficiency. Probiotics, prebiotics, and exogenous enzymes are examples of additives that enhance nutrient utilization and gut health, resulting in better performance overall. Immune-boosting substances also allow birds to fight stress, disease, and stay highly productive (David et al., 2021).

4.4 Green feed and sustainable nutrition management

Sustainable poultry nutrition aims at optimizing efficiency and reducing the environmental footprint. Nutrient bioavailability is maximized to ensure birds receive just what they need and not more. Strategies such as utilization of alternative proteins and precision feeding technologies reduce feed wastage and optimize resource use. All of these lead to environmental and economic sustainability through lower production cost and improved feed conversion ratio (Whitehead, 2002).

5 Impact of Nutrition on Chicken Health and Production Performance

5.1 Regulation of the immune system by nutrition

Proper nutrition is needed for the provision of healthy immune systems in chickens. Vitamins and trace elements play a significant role in immunity stimulation and resistance to diseases. Deficiency in nutrients has been shown to impair immune functions, predispose the birds to infection, and lead to reduced productivity in general (Gaweł et al., 2022). Nutritional interventions started early in life, like early post-hatch feeding, have been shown to enhance immune function and survival. Moreover, feed supplementation with feed containing bioactive molecules and certain vitamins can also be utilized for the enhancement of the immune system and overall poultry well-being (Azeem et al., 2023; Choi et al., 2023) (Figure 1).

5.2 Effects of feed on gut microbiota and digestive health

A balanced diet affects directly gut health and digestion of chickens. Supplementation of agronomic by-products containing fiber, such as oat hulls, affects gastrointestinal function as well as improving digestibility of nutrients. Early nutrition strategies, i.e., post-hatch nutrition, play a critical role in developing gut microbiota as well as in supporting digestive function. The use of acidifiers in poultry feed helps maintain the intestine in equilibrium by suppressing pathogenic bacteria and stimulating digestive enzyme activity (Choi et al., 2023).

5.3 Impact of nutritional optimization on meat and egg quality

Feed ingredient optimization is very important in the improvement of poultry product quality. Nutrient content modification, such as protein, amino acid profile, and energy consumption, will significantly influence meat texture, fat composition, and meat structure. Studies have demonstrated that dietary crude protein and lysine influence muscle growth, and the suggested levels lead to tenderness of the meat and reduced shear force. Additionally, incorporating bioactive compounds and nutritional supplements into broiler feed maintains even growth and improves the quality of eggs and meat (Hollemans et al., 2018).

6 Modern Farming Technologies and Nutritional Management

6.1 Precision feeding and personalized nutritional regulation

Advances in poultry nutrition have introduced several precision feeding, which is a process whereby farmers are able to tailor diets based on the exact needs of chickens at different growth stages. In doing so, birds receive the best blend of nutrients without excess or deficiency, which promotes efficiency as well as sustainability. Farmers are also able to prevent overfeeding, reduce wastage, and lower costs through real-time feed formulation adjustments. In addition, accuracy feeding enables one to respond fast to environmental and market fluctuations, which offers greater flexible and cheap poultry management (Tallentire et al., 2018).

6.2 Smart feeding systems and automation for improved feed utilization

Technology-based solutions, including automation and smart feeding systems, are transforming poultry nutrition. Such sophisticated tools use artificial intelligence (AI) and data analytics to control feed dispensing according to flock health and ambient conditions in real time. By monitoring nutrient consumption around the clock, AI-powered feeding systems can accurately predict dietary requirements, minimizing feed expense and inefficiency. Further, emerging novelty like solid-state fermentation and exogenous enzymes enhance nutrient absorption and general feed conversion efficiencies, which translate to more productive and healthy birds (Rostichelli et al., 2020; Ibrahim et al., 2023; Zhang and Lin, 2024).

6.3 Application of computer modeling and big data analysis in feed formulation optimization

Big data processing and computer simulation have revolutionized poultry feed production. Computer programs make precise adjustments to individual feed mixtures, and big data on ingredient availability, nutritional content, and price trends get computed. Optimal obtainable nutrient content in lowest-cost feeds are calculated by AI-powered models that then get supplied to farmers for usage. This strategy not only improves profitability but also maximizes resource utilization, in a way where feed is utilized to optimal benefit with minimal environmental impact (Alhotan, 2021). In addition, predictive modeling allows poultry farmers to anticipate nutritional requirements at various life stages, which translates to better growth performance and more sustainable agriculture.

7 Future Research Directions

7.1 Development of novel feed ingredients and their nutritional value assessment

While poultry production is evolving, researchers are looking for new feed ingredients that can contribute to enhanced sustainability and reduced environmental impact. Microalgae, macroalgae, duckweed, yeast protein concentrate, bacterial protein meal, and insect proteins are a few of the alternative protein sources being investigated as alternatives to traditional soybean meal. These novel ingredients provide essential nutrients and contribute to the minimization of greenhouse gas emissions and land use associated with conventional feed production. In addition, agro-industrial byproducts like Indigofera zollingeriana and palm kernel cake have been identified as promising low-cost and environmentally friendly options in poultry diets. Future research should be directed at establishing the long-term effect of these ingredients on the health and productive performance of poultry (Termizi et al., 2024).

7.2 Advances in research on the interaction between genetics and nutrition

Genetics are held accountable for chickens' sensitivity to changing diets, and attempts are being made persistently to decrease the feed management strategies based on genetic differences. Selective breeding has created populations of poultry with diverse growth characteristics and feed utilization differently, which demands modified nutrition strategies to maximize performance. Understanding the connection between genetic markers and metabolism will serve to enhance the feeding programs better (Zelenkova et al., 2021). In addition, the in vitro models of the gastrointestinal tract have been valuable in the study of nutrient digestion and absorption, as well as in attaining knowledge that will guide the formulation of improved poultry diets. Increased studies will keep enhancing feeding regimens for genetically diverse poultry flocks (Heidari et al., 2021).

7.3 Nutritional regulation and the development of antibiotic alternatives

As the usage of antibiotics declines in the poultry industry due to concerns about antimicrobial resistance, researchers are turning to nutrition-driven solutions to guarantee health and performance of flocks. Functional feed additives like probiotics, prebiotics, and plant extracts are being researched for their ability to maintain gut integrity and enhance immunity, weaning the industry from antibiotics. In addition, supplementing with collagen has also proven to boost the growth of muscle and meat quality and may hence be looked up to as an alternative potential growth promoter naturally during broiler rearing. Increased research should come in handy for evaluating efficacy as well as its long-term outcomes to prevent further interference with animals' health as well as their productivity (De Carvalho et al., 2020).

8 Concluding Remarks

Future trends in poultry nutrition are based on precision feeding and adjusting the level of nutrient consumption in relation to stages of growth. Feeding birds based on individual nutritional requirements enhances efficiency, diminishes waste, and decreases the production cost. A steady level of energy consumption and nutrient density needs to be maintained to optimize growth and muscle development in birds. In addition, the use of other proteins such as microalgae and insect protein is gaining ground as a viable substitute to reduce the use of conventional soybean-based feed.

Emerging feed formulation technologies like linear programming and artificial neural networks have also proved promising in increasing efficiency and cutting costs in production. The technologies help to ensure that the chickens are fed with the appropriate amounts of nutrients for sound growth, and also improve feed conversion and general well-being. Intelligent feeding systems keep refining poultry management by dynamic and flexible feeding schemes that respond to fluctuating environmental and market situations.

In the near future, research needs to keep developing precision nutrition strategies and investigating novel feed ingredients that are both sustainable and reduce environmental footprint. The improvement of feed formulation models will allow dietary adjustment to become more dynamic based on changing nutritional requirements of chickens during their lifecycle. Furthermore, the introduction of these technologies into commercial poultry farming should be aimed at making them available to producers of various scales. Further research proving a correlation between diet composition and gut health and general poultry welfare will be instrumental in facilitating feeding regimes that optimize productivity and animal welfare.

Acknowledgments

We would like to express our heartfelt thanks to all the teachers who have provided guidance for this study.

Conflict of Interest Disclosure

The authors affirm that this research was conducted without any commercial or financial relationships that could be construed as a potential conflict of interest.

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