**Requirements:** 1. Maintain the original format and structure. 2. The translation should be accurate, fluent, and natural. 3. Maintain professionalism and consistency. 4. Only return the translation result; do not add any explanations. **Original Text:** In the context of high feed costs and the reduction and prohibition of antibiotics in livestock farming, how to improve feed utilization, enhance chicken health, and boost production performance has always been a focus for farmers and feed companies. In recent years, the application of AKG (α-ketoglutaric acid) as a precursor to glutamine has attracted significant attention in the poultry industry. The author has reviewed several research papers on the use of AKG in broiler farming, presenting the scientific value and practical applications of this functional additive. **I. What is AKG?** AKG is an important intermediate in the tricarboxylic acid cycle of organisms and also serves as a precursor for the biosynthesis of amino acids such as glutamate, glutamine, and arginine. Simply put, it acts as the “fuel” for the cell's energy factories (mitochondria) and as a “raw material reservoir” for the synthesis of essential amino acids. Microbial-based AKG production methods are cost-effective and environmentally friendly, making them more promising for practical use. **II. The Impact of AKG on Broiler Growth Performance:** Multiple studies have consistently shown that adding appropriate amounts of AKG to the diet can significantly improve broiler growth performance: - **Yuan Huagen et al. (2022):** At 1–21 days of age, adding 0.2%–0.8% AKG to the diet significantly increased average daily weight gain. - **At 21–42 days of age, the feed conversion ratio was significantly reduced in the 0.8% AKG group.** - **For the entire period (1–42 days of age), the feed conversion ratio in the 0.8% AKG group decreased from 1.92 to 1.80.** - **Yu Qinping et al. (2010):** Adding 0.7% AKG significantly increased the weight of 2-week-old chicks and their average daily weight gain, outperforming the same dose of glutamine. The growth-promoting effect was more pronounced in the early stages, which is related to the gradual development of the chicks' intestines and their reduced need for exogenous AKG.** - **Huang Guanqing et al. (2012):** In yellow-feathered broilers, supplying 2g of AKG per day via drinking water increased average daily weight gain by 3.59%, net protein utilization by 4.57%, total serum protein content by 5.62%, and reduced serum urea nitrogen by 7.53%.” **III. How Does AKG Work?** There are four main mechanisms by which AKG exerts its effects: 1. **Improves intestinal morphology and absorption:** The intestine is the primary site for nutrient absorption, and the structure of the intestinal mucosa directly affects growth performance. Studies by Yuan Huagen et al. found that at 21 days of age, adding 0.4% or 0.8% AKG significantly increased the height of duodenal and jejunal villi and the villus-to-crib depth ratio, indicating an increased absorptive surface area and faster epithelial cell renewal. At 42 days of age, the 0.2% and 0.4% AKG groups continued to show significant advantages. 2. **Enhances intestinal barrier function and maintains intestinal health:** The integrity of the intestinal barrier is crucial for preventing pathogen invasion and maintaining chicken health. Yuan Huagen et al. found that plasma diamine oxidase (DAO) levels were lower in the AKG groups at 21 days of age, indicating reduced intestinal damage. At 42 days of age, the 0.4% and 0.8% AKG groups still had lower DAO levels. Additionally, the secretion of secretory IgA (sIgA) in the jejunum increased, indicating enhanced intestinal mucosal immunity. 3. **Boosts antioxidant capacity and reduces oxidative stress:** High-density farming and heat stress can generate excessive free radicals, affecting production performance. Yuan Huagen et al. found that AKG increased the activity of glutathione peroxidase (GSH-Px) and reduced malondialdehyde (MDA) levels in the jejunum, indicating a reduced oxidative stress. 4. **Promotes immune organ development and enhances immune function:** Studies by Yu Qinping et al. showed that AKG positively affected the development of immune organs, leading to increased bursa of Fabricius weight and index at 6 weeks of age. **IV. The Impact of AKG on Nutrient Metabolism:** - **More thorough digestion:** Yuan Huagen et al. found that from 18–20 days of age, the apparent metabolic rates of crude protein, crude ash, and dry matter were higher in the AKG groups. From 39–41 days of age, the apparent metabolic rate of crude fat was higher in the 0.8% AKG group. - **Better organ development:** Well-developed digestive organs are essential for healthy growth. - **Improved serum biochemical indicators:** Studies by Yuan Huagen et al. showed increased serum glucose levels and reduced alkaline phosphatase activity in the 0.8% AKG group, indicating good liver health. Additionally, AKG reduced serum aspartate aminotransferase and alanine aminotransferase levels, suggesting no liver damage. **V. The Impact of AKG on Organ Development:** - **Stronger bodies:** At 42 days of age, the relative mass of the gizzard and other digestive organs was increased in the AKG groups, indicating better organ development. **VI. The Impact of AKG on Serum Biochemical Indicators:** - **More vigorous metabolism:** Studies by Yuan Huagen et al. showed increased serum glucose levels and reduced alkaline phosphatase activity in the 0.8% AKG group. **VII. Practical Application Suggestions:** - **Recommended addition amounts and effects:** - **1–21 days of age:** 0.7%–0.8% to promote early growth, improve intestinal development, and increase daily weight gain. - **After 21 days of age:** 0.4%–0.8% to maintain intestinal health, reduce feed conversion ratio, and improve feed utilization. - **Overall use of 0.8% yields the best results with a high cost-effectiveness ratio.** - **For slow-growing breeds like yellow-feathered broilers, supplying 2g of AKG per bird per day via drinking water can also achieve significant benefits.** - **Expected effects:** - **Growth performance:** 5%–10% increase in average daily weight gain, 5%–8% reduction in feed conversion ratio. - **Feed utilization:** 5–15% increase in the apparent metabolic rates of crude protein, crude fat, and dry matter. - **Intestinal health:** 10%–20% increase in villus height, enhanced intestinal barrier function. - **Antioxidant capacity:** 30%–80% increase in GSH-Px activity, 30%–60% reduction in MDA levels. - **Immune function:** 30%–50% increase in intestinal sIgA levels. **Conclusion:** As a multifunctional feed additive, AKG improves broiler growth performance and health by enhancing intestinal structure, strengthening the intestinal barrier, boosting antioxidant capacity, and promoting immune organ development. In the current context of limited feed resources and increased environmental regulations, AKG not only improves feed utilization and reduces costs but also reduces nitrogen emissions, making it a valuable additive with both economic and social benefits. **Warm Reminder:** The data comes from multiple published studies. Actual application effects may vary depending on factors such as chicken breed, age, diet composition, and farming environment. It is recommended to conduct small-scale trials before large-scale use. **References:** [1] Yu Qinping, Chen Yanqun, et al. The impact of α-ketoglutaric acid in the diet on the growth performance and tissue organ development of chicks. *China Animal Science and Veterinary Medicine*, 2010, 37(10): 10-14. [2] Huang Guanqing, Yu Qinping, et al. The impact of α-ketoglutaric acid on the feed metabolism and protein metabolism of yellow-feathered broilers. *China Feed*, 2012, 18: 22-24. [3] Yuan Genhua, An Dong, Xu Yaya, et al. The impact of α-ketoglutaric acid on broiler growth performance, digestion, and metabolism. *Jiangsu Agricultural Sciences*, 2022, 50(16): 174-179. [4] Yuan Genhua, An Dong, Xu Yaya, et al. The impact of α-ketoglutaric acid on the intestinal barrier function of broilers. *China Feed*, 2022, 18: 63-66.