An experiment was conducted to test the hypothesis that inclusion of spray dried plasma (SDP) in diets increases apparent total tract digestibility (ATTD) and/or the standardized total tract digestibility (STTD) of gross energy (GE) and nutrients in diets for young pigs, and that ATTD of energy and nutrients or STTD of P in individual ingredients are additive in diets containing SDP. Eighty barrows (body weight: 9.30 ± 0.97 kg) were housed in individual metabolism crates and allotted to 1 of 10 diets in a randomized complete block design with 8 replicate pigs per diet. Four diets were prepared without SDP and contained ingredients commonly used in the United States, Canada, the European Union, or Asia. Four additional diets were prepared by mixing 94% of the previous four diets and 6% SDP. A diet containing SDP as the sole source of P and a P-free diet were also formulated. The ATTD of GE and nutrients and the STTD of P were calculated in all diets except the P-free diet and for the four regional diets containing 6% SDP, values were also predicted from the digestibility obtained in SDP alone and the regional diets without SDP. Differences between measured and predicted values for digestibility of GE and nutrients were also calculated. An interaction was observed between SDP and region for the ATTD of soluble dietary fiber where the digestibility decreased (P < 0.05) for pigs fed the U.S. diet with 6% SDP compared with 0% SDP, but that was not the case for the other regional diets. There was no interaction for the ATTD of GE, N, insoluble dietary fiber (IDF), total dietary fiber (TDF), Ca, and P or the STTD of P, but the ATTD and STTD values were greater (P < 0.05) or tended to be greater (P < 0.10%) when 6% SDP was included in the diet compared with diets with 0% SDP. The ATTD of GE, IDF, TDF, and P, and the STTD of P was greater (P < 0.05) for the Asia diet compared with the other diets regardless of inclusion of SDP. The measured ATTD of IDF and TDF was greater (P < 0.05) than the predicted values for the U.S. and European Union diets, and the measured ATTD of GE, N, Ca, and P and the STTD of P was greater (P < 0.05) than the predicted values for the Asia diet. In conclusion, addition of 6% SDP to a diet will increase the ATTD of energy and nutrients and the STTD of P in diets for weanling pigs, and in some cases, the measured ATTD of energy and nutrients or the STTD of P by pigs fed diets containing SDP is greater than predicted from individual ingredients.
Keywords: additivity; apparent total tract digestibility; endogenous phosphorus losses; pig; spray dried plasma.
© The Author(s) 2023. Published by Oxford University Press on behalf of the American Society of Animal Science.