Effect of Solid-State Fermented Cottonseed Meal on Broiler Growth Performance, Carcass Traits and Blood Biochemical Parameters: A Systematic Review

Cottonseed meal (CSM) has emerged as an alternative source of protein-based poultry feed because of the increasing cost and scarcity of soybean meal. However, it contains toxic gossypol, which restricts its use. This systematic review examines solid-state fermented CSM's impact on broiler chickens, focusing on growth performance, carcass traits, and blood parameters. To identify relevant papers, a comprehensive search of Web of Science, Scopus, and PubMed was conducted. In accordance with the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) methodology, peer-reviewed experimental articles published in English up to September 2023 were screened. A total of 60 articles were evaluated over four stages, resulting in 9 articles that met the predefined inclusion and exclusion criteria. The reduction in gossypol content was effective with bacteria like Bacillus subtilis, Aspergillus oryzae, and Aspergillus niger. The content of free gossypol in CSM is significantly reduced after solid-state fermentation using various microorganisms. Fermented CSM increased the body weight gain and feed intake of broilers, while maintaining feed efficiency, and improved growth performance. Fermented CSM included in diets positively affected carcass traits, including increased carcass weight and breast muscle development. It also resulted in decreased fat content and enhanced immune organ development. An improvement in total protein, albumin, and immunoglobulin levels was observed in blood biochemical parameters, suggesting an improved humoral immune response. Depending on the microorganisms used and their concentrations, fermented CSM also had positive effects on cholesterol, triglycerides, and LDL levels. Solid-state fermented CSM can be an effective and sustainable source of protein for broiler chickens. A future research focus should be on long-term effects, underlying mechanisms, economic feasibility, and scalability. In addition, it could be used in novel feed formulations and other livestock species to further enhance animal agriculture.