Abstract: The objective of this study was to determine the true P digestibility, the gastrointestinal endogenous P outputs associated with rapeseed and soybean meals. Six×Yorkshire Landrace barrows, with initial body weight of (24.8±1.42) kg, were fed six diets using a 6×6 Latin square design. The pig feed was compounded based on soybean meals, corn starch and glucose, including six levels of P (0.11%, 0.22%, 0.33%, 0.44%, 0.55%, 0.53% ), and the rapeseed and soybean meals were the only P source. Chromic oxide (3.5 g/kg of diet, as-fed basis) was included in the diets as digestibility marker. The experiment was divided into 6 stages and each stage lasted for a period of 8 d, of which 6 d for adaptation and 2 d for collection of representative fecal samples. The results showed that the P endogenous outputs for pig were 0.2108 g/kg DMI. The apparent P digestibility values were-0.30%, 25.77%, 7.25%, 16.29%, 16.54%, 23.62%, 15.04% and 28.97% for rapeseed meals, soybean meals, diet1, diet2, diet3, diet4, diet5 and diet6, respectively, and the true P digestibility for above treatments were 10.21%, 32.94%, 26.22%, 23.62%, 22.95%, 23.57%, 22.81% and 32.94%, respectively. In comparison with apparent P digestibility, the true P digestibility could better reflect the reality of P digestion from feed and should be used in swine diet formulation because of its stability in the same ingredients.

Key words: Growing pigs, Rapeseed meal, Soybean meal, Phosphorus, Endogenous outputs, True digestibility

CLC Number: 

• S858.28