166 Enhanced torula yeast has increased nutritional value compared to fish meal when fed to weanling pigs

The hypothesis that the standardized ileal digestibility (SID) of AA, concentration of ME, and the standardized total tract digestibility (STTD) of P in an enhanced torula yeast (ETY; Arbiom, Raleigh, NC) are not different from values obtained in Menhaden fish meal (FM) was tested. In Exp. 1, 6 ileal cannulated barrows (11.7 ± 0.4 kg) were allotted to a replicated 3 × 3 Latin square with 3 diets (ETY, FM, and N-free) and 3 7-d periods. Ileal digesta were collected on d 6 and 7 of each period. Data were analyzed using the Proc Mixed with diet as main effect and pig as random effect. The SID of AA was greater (P < 0.05) in ETY than in FM (Table 1). In Exp. 2, 24 barrows (14.4 ± 1.1 kg) were individually housed in metabolism crates and allotted to a corn diet or diets based on corn and ETY or corn and FM. Feces and urine were collected for 5 d. Data were analyzed as in Exp. 1. No difference in ME between ETY (3,636 kcal/kg DM) and FM (3,611 kcal/kg DM) was observed. In Exp. 3, 32 barrows (11.9 ± 1.1 kg) were allotted to 4 diets in a 2 × 2 factorial with 2 ingredients (ETY and FM) and 0 or 500 units/kg of phytase. Housing and fecal sample collection was as in Exp. 2. Data were analyzed as in Exp. 1 with diet and phytase as main effects. Phytase did not influence STTD of P, but the STTD of P in the ETY (91%) was greater (P < 0.05) than in FM (68%). In conclusion, the SID of AA and the STTD of P in ETY is greater than in FM, but the ME in ETY is not different from FM.