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.

Dried blood meal is commonly used as a high-quality protein source in nursery pig diets. Growth studies have indicated that blood meal can be a better protein source than dried skim milk, fish meal, and soy protein concentrate.  However, the growth effects of blood meal vary across studies; this may be due to differences in protein quality.

Limited data exist on digestibility of crude protein and amino acids in blood meal produced from different species and with different drying methods.  Therefore, an experiment was conducted to measure apparent (AID) and standardized (SID) ileal digestibility of crude protein and amino acids in two sources of blood meal.