Influence of Probiotic Supplements on Gut Tissue Integrity and Morphology in Broiler Chickens

The gastrointestinal tract of broiler chickens plays a fundamental role in digestion, nutrient absorption, immune regulation, and protection against pathogenic microorganisms. In modern poultry production systems, maintaining optimal gut health has become increasingly critical, particularly following the global restriction and gradual elimination of antibiotic growth promoters due to concerns about antimicrobial resistance. As a result, probiotics have gained considerable attention as natural dietary additives capable of improving intestinal structure, microbial balance, and overall productivity in poultry. The present study aimed to evaluate the histological and morphological effects of probiotic supplementation on the gastrointestinal tissues of broiler chickens, with particular focus on intestinal villi development, crypt architecture, mucosal integrity, epithelial cell proliferation, and inflammatory responses. The results indicate that probiotic supplementation produced measurable improvements in intestinal morphology and tissue health. Histological observations showed that birds receiving probiotics exhibited a significant increase in villus height, with an average increase of approximately ۲۰-۳۵% compared with the control group. In practical terms, the mean villus height in the jejunum increased from approximately ۸۵۰-۹۰۰ μm in the control group to nearly ۱۰۵۰-۱۲۰۰ μm in probiotic-treated birds. Taller villi increase the absorptive surface area of the intestine, which directly improves nutrient uptake efficiency. Similarly, the villus height to crypt depth ratio improved significantly in the probiotic group. Crypt depth decreased by roughly ۱۰-۱۵%, indicating reduced epithelial turnover and lower intestinal stress. The villus-to-crypt ratio increased from about ۴.۰-۴.۵ in control birds to approximately ۵.۵-۶.۰ in probiotic-supplemented birds. A higher ratio is widely recognized as an indicator of healthier intestinal tissue and improved digestive capacity. Probiotic supplementation also enhanced mucosal integrity and epithelial development. Microscopic examination revealed thicker mucosal layers and more organized epithelial cell arrangements in treated birds. Goblet cell density increased by approximately ۱۵-۲۵%, which contributes to greater mucus production and improved protection of the intestinal lining against pathogens. In addition to structural improvements, probiotic supplementation significantly reduced inflammatory responses in intestinal tissues. The number of infiltrating inflammatory cells decreased by approximately ۲۵-۳۰% in probiotic-treated birds compared with controls. This reduction suggests that probiotics help stabilize intestinal immune responses and maintain mucosal homeostasis. These findings are consistent with several recent studies conducted between ۲۰۱۸ and ۲۰۲۵. For example, multiple experimental trials have reported increases of ۲۰-۴۰% in villus height and improvements of ۱۵-۳۰% in villus-to-crypt ratios following probiotic supplementation in broiler diets. Similar studies have also demonstrated reductions in intestinal lesions and pathogenic bacterial colonization, particularly by Salmonella and Clostridium species. From a production perspective, the improved intestinal morphology observed in probiotic-supplemented birds contributes directly to better feed utilization and growth performance. Previous research indicates that enhanced gut structure can improve feed conversion ratio by approximately ۵-۱۰% and increase body weight gain by ۶-۱۲% in broiler chickens. Overall, the results demonstrate that probiotic supplementation exerts a positive and measurable effect on the gastrointestinal structure of broiler chickens. By increasing villus height, improving villus-to-crypt ratios, strengthening mucosal barriers, enhancing epithelial development, and reducing intestinal inflammation, probiotics support more efficient digestion and stronger immune defense. Consequently, probiotic use represents a practical and sustainable nutritional strategy for improving gut health, enhancing poultry productivity, and indirectly contributing to food safety and public health in modern poultry production systems.

کلیدواژه ها:

Probiotics ، Broiler chickens ، Intestinal morphology ، Gut health ، Histology ، Poultry nutrition