Effects of faba bean extrusion and phytase supplementation on performance, phosphorus and nitrogen retention, and gut microbiota activity in broilers

BACKGROUND Faba bean (FB) can be used in poultry diets as a protein source alternative to soybean meal. This study evaluated the effect of extrusion of low‐tannin FB and phytase supplementation on performance, phosphorus (P) and nitrogen (N) retention, and gut microbiota activity in broiler chickens. Raw or extruded FB meal was included in broiler diet at 300 g kg −1 . The experimental treatments additionally differed in nutrient level (adequate, or calcium, P, and protein reduced) and phytase supplementation. RESULTS Broiler performance was not affected by the dietary treatments. Extrusion and a reduced nutrient content did not affect P and N retention coefficients, but they increased when the reduced diets were supplemented with phytase. In the ileal digesta, FB extrusion increased the activities of bacterial α ‑ and β ‐glucosidase, β ‐galactosidase, and β ‐glucuronidase, but acetate and total short‐chain fatty acids (SCFAs) concentrations were higher only in birds fed extruded FB supplemented with phytase. In the cecal digesta, FB extrusion increased the activities of bacterial α ‑ and β ‐glucosidase, α ‐galactosidase and β ‐glucuronidase, and phytase supplementation decreased β ‐glucosidase and β ‐glucuronidase activities, but acetate, butyrate and valerate and total SCFA concentrations were lower in birds fed extruded FB. CONCLUSION Good performance of broilers could be obtained using diets containing 300 g kg −1 raw FB. The extrusion process does not improve FB nutritive value and may negatively affect the activity of cecal microbiota. Phytase supplementation allows lowering calcium, inorganic P, and protein level in diets with FB, and reduces P and N excreted in droppings, with a positive effect on the environment. © 2020 Society of Chemical Industry