Dose–response meta-analysis of chitosan oligosaccharide in broilers

A bioactive feed additive that has antimicrobial, antioxidant, and immunomodulatory effects is chitosan oligosaccharide (COS), a bioavailable polyphenol. The effects of COS supplementation on broiler chickens were quantified via a dose–response meta-analysis that combined data from 19 studies. A random-effects model was used to determine the effect sizes, with a pooled effect size that increased final body weight and average daily gain and reduced the feed conversion ratio. The meta-analysis results also revealed improvements in meat quality, drip loss, cooking loss, and decreased shear force. However, several characteristics, such as weight and breast yield, also decreased with COS supplementation. COS also led to a decrease in abdominal fat and an improvement in the development of immune organs, particularly Fabricius' bursa and the thymus. According to pooled results from the meta-analysis, COS supplementation was associated with reduced total serum cholesterol, alanine aminotransferase (ALT), aspartate aminotransferase (AST), and low-density lipoprotein (LDL) levels, whereas high-density lipoprotein (HDL) and triglyceride levels remained unchanged. In addition, cytokine profiles were detected, leading to increases in interleukin-10, interleukin-1β (IL-1β), and tumour necrosis factor-α (TNF-α) levels. The growth phase and nutritional interactions were used to predict COS levels between 2.4 and 4.6 g/kg, as predicted by response surface modelling. In summary, the evidence from this dose–response metaanalysis supports the use of COS as a sustainable feed additive that promotes the growth of carcases with different qualities to improve meat quality and reduce heat stress.