Global poultry production continues to expand rapidly to meet the growing demand for affordable and high-quality animal protein. However, this growth raises pressing concerns about environmental sustainability, natural resource use, and public health. Although current initiatives, such as improved housing systems, optimized feeding practices, and partial soybean meal substitution, have helped mitigate some impacts, comprehensive integrated solutions remain underexplored. This review synthesizes emerging nutritional and management innovations that enhance the sustainability of poultry production while maintaining profitability. It addresses three central research questions: (1) Which alternative feed ingredients most effectively preserve animal performance while minimizing environmental burdens? (2) How can environmental management practices enhance resource efficiency and waste valorization? (3) What roles do life cycle assessment methodologies and policy frameworks play in advancing sustainable poultry systems? Evidence from 100 peer-reviewed studies, industrial data, and field analyses reveals that incorporating insect meals, algae, and agro-industrial by-products can reduce dependence on soybean meal by 20–40% and improve feed efficiency by 5–12% across various poultry production systems. Furthermore, integrating environmental management strategies, such as manure valorization, efficient water and energy use, and the adoption of renewable energy, substantially reduces greenhouse gas emissions and promotes circular economic principles. Life cycle assessment studies confirm that combined dietary and management interventions yield greater reductions in carbon footprint than isolated measures. Future research should focus on optimizing interactions among feed strategies, environmental management, and policy frameworks through digital technologies, nanomaterial-based feed additives, and region-specific sustainability plans to accelerate the transition toward resilient, climate-smart poultry production systems.

This study investigated the potential of black soldier fly larvae (BSFL) meal to replace soybean meal in broiler diets by evaluating growth performance, carcass traits, meat quality, and blood biochemical responses. A total of 160 ten-day old Ross 708 chicks (216.74 ± 0.74, g) were randomly assigned to four dietary treatments containing 0%, 20%, 40%, or 60% BSFL meal replacing soybean meal on a 100% equivalent basis, respectively, and evaluated during the starter (10–21 days), grower (21–42 days), and overall (10–42 days) phases. Carcass characteristics, meat color, and blood biochemistry were assessed on day 42. Data was analyzed using polynomial (linear and quadratic) contrasts. Increasing dietary BSFL levels resulted in significant reductions in body weight, average daily gain, and feed intake, while the feed conversion ratio increased linearly. Carcass yield decreased to higher inclusion levels, accompanied by a marked increase in gizzard weight. Meat color (L*, a*, b*) remained largely unchanged across treatments. Blood biochemical analysis revealed linear and quadratic shifts in key metabolites, enzymes, and electrolytes, including reductions in aspartate aminotransferase, bilirubin, and creatine phosphokinase, as well as altered calcium and phosphorus concentrations. Overall, BSFL meal inclusion as 20% replacement improved growth performance and stimulated beneficial lipid and protein metabolism adaptations in broilers.

Brown mushroom stem (BMS), a nutrient-rich by-product of the mushroom processing industry, represents a potential sustainable feed ingredient for poultry. However, its effects on intestinal morphology and barrier-related gene expression in layer chicks are not well characterized. This study evaluated the influence of dietary BMS on ileal morphology and intestinal barrier-related gene expression in layer chicks. A total of 160 Lohmann LSL Lite chicks were randomly allocated to 4 dietary treatments: a control diet and control diets containing 2%, 4%, or 6% BMS as partial replacements for soybean meal on an equivalent basis, respectively. Each treatment had 5 replicates with 8 birds per replicate, and the trial lasted 36 d. Ileal samples were collected for histomorphological evaluation and quantitative real-time PCR of barrier-associated genes, including claudin-1 (CLDN1), occludin (OCLN), tight junction protein 1 (TJP1), tight junction protein 2 (TJP2), and mucin-2 (MUC2). Data were analyzed using one-way ANOVA, and orthogonal polynomial contrasts were applied to determine linear and quadratic responses to increasing BMS inclusion levels. Villus height decreased in BMS-fed groups compared with the control (linear and quadratic effects, p < 0.001), whereas crypt depth showed a quadratic response with the lowest value at 4% BMS (p < 0.001). Expression of CLDN1 mRNA was significantly elevated at 2% BMS but declined at higher inclusion levels (quadratic effect, p = 0.001). In contrast, TJP2 mRNA expression decreased with increasing BMS inclusion (linear effect, p = 0.009). No significant differences were observed for OCLN, TJP1, or MUC2 mRNA expression (p > 0.05). A composite index of barrier-related gene expression was numerically the highest at 2% BMS supplementation but did not differ significantly among treatments. These findings suggest that low dietary inclusion of BMS may support intestinal barrier-related gene expression in layer chicks, although higher levels may alter intestinal morphology without corresponding changes in barrier-related gene expression. Optimizing BMS inclusion could support sustainable poultry production by utilizing mushroom processing by-products as an alternative feed ingredient.