I'm Dr. Rommel Sulabo from the Hans Stein Monogastric Nutriton 
Laboratory here at the University of Illinois, and today I will be 
discussing one of our recent research studies evaluating the amino acid 
digestibility of blood meal fed to weanling pigs.

Dried blood meal is an animal protein product used more commonly in 
nursery pig diets. Numerous growth studies have demonstrated that blood 
meal can be a better protein source than other commonly used specialty 
protein sources in starter diets, such as dried skim milk, select 
menhaden fish meal, and soy protein concentrate. However, these growth 
effects of blood meal vary across studies, which may be attributed to 
large differences in protein quality among blood meals.

To produce blood meal, whole or coagulated blood is dried in a variety 
of processing methods and may be sourced from either porcine, bovine, or 
avian origin. Thus, the nutritional value of blood meal may depend on 
the drying procedure or animal origin. Currently, there is limited data 
on the digestibility of crude protein and amino acids in blood meals 
produced using different drying methods and animal origin. The current 
NRC only reported true ileal digestibility values of amino acids for 
spray- or ring-dried blood meal. Therefore, the objective of this 
project was to measure the apparent and standardized ileal digestibility 
of amino acids in two sources of blood meal fed to weanling pigs.

For this study, we used a total of eight weanling barrows that were 
equipped with a T-cannula in the distal ileum and allotted to a 
replicated 4x4 Latin square design with four diets and four periods in 
each square. There were four diets in this study. The first diet was a 
casein-based diet, and two diets were based on a mixture of casein and 
each source of blood meal. We compared two blood meal sources. The first 
was a spray-dried blood meal of porcine origin produced by Belstra 
Milling out of Demotte, Indiana, and the second was drum-dried blood 
meal of bovine origin produced by Cargill out of Skylar, Nebraska. The 
Cargill product was processed using a continuous drum dryer set at about 
80 degrees Celsius with a retention time of about 20 minutes. The last 
diet was a nitrogen-free diet that was used to measured basal endogenous 
losses of amino acids and protein. All of the diets contained 0.4% 
chromic oxide to serve as our indigestible marker. All of the pigs in 
this study were fed at the level of 2.5 times the maintenance energy 
requirement, and water was made available at all times throughout the 
study. The experimental diets were fed for a period of seven days, with 
the initial five days serving as our adaptaton period to the diet, while 
days six to seven was devoted for ileal digesta collection. At the end 
of the study, all diets and ileal digesta samples were prepared and 
analyzed for dry matter, chromium, crude protein, and amino acids to 
calculate for both apparent and standardized ileal digestibility of 
crude protein and amino acids in the two blood meal sources.

Now, let's discuss the results of this study. We observed that both 
blood meals contained high levels of crude protein, lysine, and valine, 
regardless of the drying method used or animal origin, which conformed 
with other previous reports. The spray-dried porcine blood meal 
contained about 98% crude protein, while the drum-dried bovine blood 
meal contained about 95% crude protein. The two blood meal sources also 
contained similar levels of indispensable and dispensable amino acids. 
The total lysine concentration of the two blood meal sources was 7.7 to 
8.6%, which is within the range observed in other studies. However, the 
drum-dried bovine blood meal contained twice the concentration of 
methionine in spray-dried porcine blood meal. As expected, isoleucine 
had the lowest concentration among all indispensable amino acids for 
both blood meal sources, ranging between 0.42 to 0.55%. However, these 
were lower than those previously reported. After isoleucine, cysteine 
and methionine were the next limiting amino acids in both blood meal 
sources. Except for isoleucine, the digestibility of all indispensable 
amino acids in the two blood meal sources were relatively high, ranging 
between 90-96%, and 80-92% in spray-dried porcine and drum-dried bovine 
blood meal respectively. The standardized ileal digestibility of 
isoleucine was 63 and 72% for the spray-dried and drum-dried blood meal 
respectively. More importantly, the standardized ileal digestibility 
value of lysine was 90 to 96% for the two blood meal sources. This 
conformed with the values reported by NRC, which is 94% true ileal 
digestible lysine in spray- or ring-dried blood meal. However, the SID 
of lysine was lower for the drum-dried bovine blood meal than the 
spray-dried porcine blood meal. This suggest that the drying method used 
to produce the two blood meals may have affected the digestibility of 
heat-labile amino acids, especially lysine.

Though SID values of most indispensable amino acids were greater for the 
spray-dried porcine blood meal, the digestible amino acid contents were 
similar between the two blood meal sources. This is mainly due to the 
higher total concentration of most indispensable amino acids in 
drum-dried bovine blood meal. There may be differences in amino acid 
concentrations between animal origins of blood meal. However, there is a 
wide variation in amino acid content of blood meal within each origin. 
For example, the lysine and the isoleucine content of bovine blood meal 
ranged from 7.66 to 8.59% and 0.42 to 1.04% respectively. Whereas 
porcine blood meal contained 7.53 to 7.73% lysine and 0.55 to 0.91% 
isoleucine. Previously, research from Kansas State University compared 
spray-dried blood meals from different animal origins and observed no 
differences in growth performance of weanling pigs. Thus, the results of 
this study and the current experiment suggest that animal origins do not 
affect protein quality of blood meals.

In conclusion, the current data showed that the two blood meal sources 
contained high levels of digestible crude protein and most indispensable 
amino acids. The spray-dried porcine blood meal had greater standardized 
ileal digestibility of most indispensable amino acids than the 
drum-dried bovine blood meal. The drying procedure used to produce the 
two blood meals affected amino acid digestibility, especially lysine. 
However, both blood meals contained low concentrations of digestible 
isoleucine, methionine, and cysteine, and thus supplementation of 
isoleucine and methionine must be considered to increase the feeding 
value of these blood meals to nursery pigs.

Thank you very much for listening, and we hope you can join us again on 
our next podcast.