Determination of ileal digestibility of phosphorus in fishmeal for broilers using the direct method

Ileal digestibility is suggested as the most accurate measurement of the actual amount of phosphorus (P) available to poultry. Limited information is available regarding the assessment of the digestible P content in fish meal. Therefore, the objective of this study was to determine the standardized ileal digestibility coefficient of P in various types of fish meals for broilers, using the direct method. Three fish meal were labeled according to different crude protein levels: 550 (FM550), 600 (FM600), and 650 (FM650) g/kg. The P digestibility was evaluated by the direct method, which formulates semi-purified diets in which the test ingredient is the only source of P present. Apparent digestibility values are corrected into standardized digestibility by measuring endogenous losses using P-free diet. So, four experimental diets were formulated for this study, one without P and three diets incorporating different fish meal. At 19 days of age, 216 broilers were distributed, in metabolic cages, in a completely randomized design with four treatments, and each treatment was replicated nine times, with six birds per experimental unit. At 21 days of age, all birds were euthanized to collect ileal digesta content. Digesta and diets were analyzed for titanium dioxide, total P, and dry matter. Ileal endogenous P loss, apparent and standardized ileal digestibility coefficient and of each fishmeal were calculated. The ileal endogenous loss was 190 mg P/kg of dry matter intake. The apparent ileal digestibility coefficient was 0.667, 0.775, and 0.804 and the standardized ileal digestibility coefficient was 0.680, 0.792 and 0.821 for FM550, FM600, FM650, respectively. FM650 and FM600 showed higher P digestibility coefficients than FM550 (P < 0.05). These results highlighting the importance of considering phosphorus digestibility in the feed composition and diet formulation of broiler diets. •Standardized ileal digestibility of P of three fish meal for broiler was determined by the direct method.•Standardized ileal digestibility coefficient of P ranged from 0.680 to 0.821.•P digestibility was higher in fish meals with higher protein contents.•It’s important consider variation in P digestibility in fish meal.