The U.S. slaughter industry produces blood co-products that may be used in diets for nursery pigs because of the high concentration and quality of protein they contain. The quality of protein in blood products can differ based on the processing techniques used. In particular, products which are heated to too high a temperature during processing can sustain heat damage to amino acids due to the Maillard reaction. Lysine is particularly susceptible to heat damage.
An experiment was performed to determine the comparative amino acid digestibility in five different blood products fed to weanling pigs. Three are spray-dried products, which are dried quickly at temperatures of up to 225˚C. Spray-dried animal blood (SDAB) is manufactured from whole blood containing an anticoagulant. Spray-dried plasma protein (SDPP) is manufactured from blood which has had the plasma separated out by centrifugation. Spray-dried blood cells (SDBC) are the red blood cells left after plasma separation. In addition to the spray-dried products, two sources of blood meal were tested – one from an avian source (avian blood meal, or ABM) and one from a porcine source (porcine blood meal, or PBM). These blood meals were dried using drum driers instead of spraydriers.