Enzyme super-dosage mitigates growth impairment in broilers fed high levels of Chlorella vulgaris and improves meat fatty acid composition

1. This study evaluated whether pancreatin super-dosage or extrusion could mitigate the negative effects of high dietary inclusion of Chlorella vulgaris (20%), on broiler growth performance. It assessed changes in meat traits and preliminary health-related indicators.2. A total of 120, 7-d old broilers were allocated into one of four treatments; a control diet, or supplemented with either 20% untreated C. vulgaris, 20% C. vulgaris plus 0.30% pancreatin or 20% extruded C. vulgaris. Growth performance was monitored weekly from d 7 to 35 of age, with post-slaughter evaluations focusing on meat traits and organ metrics. Excreta quality and beak adhesion scores were recorded weekly.3. The results indicated that 20% C. vulgaris inclusion impaired growth performance and pancreatin supplementation restored final body weight to levels comparable to those of controls by d 35 of age (p < 0.001). Extrusion affected feed conversion ratio (FCR; p < 0.001). The Chlorella. vulgaris diets improved breast muscle yield and carcass yields increased when treatments were applied (p < 0.001 and p = 0.010, respectively).4. Meat fatty acid profile was improved which was characterised by a reduced n-6/n-3 ratio (p < 0.001), alongside enhanced antioxidant capacity (p = 0.030) and increased yellowness (p < 0.001). No adverse effects were observed in health-related indicators, including excreta quality, digesta viscosity and organ measurements (p > 0.05), although feed adhesion to the beak was increased in all C. vulgaris diets, particularly the extruded form (p < 0.001).5. In conclusion, incorporating 20% C. vulgaris into broiler diets was feasible when combined with enzyme super-dosage, allowing recovery of final body weight and improving meat quality without compromising animal health. However, extrusion at this inclusion level impaired feed efficiency.