123 Effects of Different Protein Sources Containing Highly Digestible Phosphorus on the Basal Endogenous Loss of Phosphorus

Abstract

Abstract The objective of this experiment was to test the hypothesis that the basal endogenous loss of P from pigs fed a diet containing blood plasma, casein, or potato protein concentrate is not different from that of pigs fed a diet containing gelatin. Pigs (n = 40; body weigh =: 19.34 kg) were housed in metabolism crates and were randomly allotted to four low-P diets containing 20% gelatin, 20% blood plasma, 18.5% casein, or 20% potato protein concentrate. With the exception of Ca and P, diets were formulated to meet the requirements for 11 to 25 kg pigs. Feces and urine samples were collected separately for 4 d following a 5-d adaptation period. Feces samples were dried, ground, and analyzed for Ca and P, and urine samples were also analyzed for Ca and P. Data were analyzed using a model that included diet as fixed effect and replicate as random effect. Results indicated that feed intake and fecal excretion of dry matter were greater (P < 0.05) in pigs fed diets containing blood plasma, casein, and potato protein concentrate compared with pigs fed the gelatin diet, with pigs fed potato protein concentrate having the greatest (P < 0.05) excretion (Table 1). The apparent total tract digestibility of dry matter was least (P < 0.001) in pigs fed the diet containing potato protein concentrate, but there were no differences among gelatin, blood plasma, and casein diets. No differences were observed in the standardized total tract digestibility of P among diets. Basal endogenous loss of P was not different between the gelatin and casein diets, but pigs fed diets containing blood plasma or potato protein concentrate had greater (P < 0.001) basal endogenous loss of P compared with pigs fed gelatin or casein diets. In conclusion, the basal endogenous loss of P was greater in diets containing blood plasma and potato protein concentrate compared with gelatin. However, casein could be an alternative to gelatin to estimate the basal endogenous loss of P because casein provides a greater amount of P compared with gelatin that compensates for the deficient level of P in gelatin, but does not affect values for the basal endogenous loss of P.