Dried Fermentation Biomass (Ajinomoto Heartland LLC) is a co-product of the commercial production of lysine. Peptone 50 and PEP2+ (TechMix LLC) are co-products of heparin production by the human pharmaceutical industry. The latter two are produced from hydrolyzed pig intestines co-dried with a vegetable protein (Peptone 50) or enzymatically processed vegetable proteins (PEP2+). These co-products are being investigated as possible cost-effective replacements for fish meal in weanling pig diets.

An experiment was performed to measure the apparent and standardized ileal digestibility of CP and amino acids by weanling pigs in Dried Fermentation Biomass, Peptone 50, and PEP2+, respectively, and to compare these values to digestibility values obtained in fish meal.

Weanling barrows were fed one of six diets.  One diet contained soybean meal as the sole source of protein and amino acids. Three diets were based on a combination of soybean meal and Dried Fermentation Biomass, Peptone 50, and PEP2+, respectively. One diet contained fish meal as the protein source. Finally, an N-free diet was used to measure basal endogenous losses of amino acids and protein.

Protein and amino acid content

Dried Fermentation Biomass had the greatest concentration of crude protein and all indispensable amino acids of all ingredients tested (Table 1). Peptone 50 and PEP2+ contained more crude protein than soybean meal, but less than fish meal. The concentrations of most indispensable AA in PEP2+, including lysine, were similar to fish meal, but were greater than in Peptone 50 and soybean meal. Both Peptone 50 and PEP2+ had less tryptophan than fish meal and soybean meal.  

Protein and amino acid digestibility

With the exception of tryptophan, for which there was no significant difference, standardized ileal digestibility of crude protein and all indispensable amino acids was greatest in soybean meal.

Digestibility of crude protein and all indispensable amino acids, as well as mean digestibility of all amino acids, in Dried Fermentation Biomass was greater than or comparable to digestibility values for fish meal.  Dried Fermentation Biomass and soybean meal did not differ in digestibility of crude protein and all indispensable amino acids except for methionine and phenylalanine.

In Peptone 50, digestibility of crude protein and most amino acids was less than in soybean meal, but did not differ from fish meal except for threonine.

PEP2+ had the lowest digestibility values for crude protein and almost all amino acids.

Key points

• Dried Fermentation Biomass contains a high concentration of crude protein and indispensable amino acids. Its crude proteins and amino acids are also highly digestible. Dried Fermentation Biomass provides the greatest digestible amino acid content of all ingredients tested and may be used as a potential replacement for fish meal in diets fed to weanling pigs.
• The digestibility of most amino acids in Peptone 50 was similar to both fish meal and soybean meal. Crude protein and most amino acids in PEP2+ were the least digestible among all the protein sources that were used in this experiment.
• Peptone 50 and PEP2+ provide less digestible protein and amino acids than fish meal, but if the inclusion rate is increased, it is possible that they may replace fish meal in diets fed to weanling pigs.

Table 1. Analyzed nutrient composition (as-fed basis) of soybean meal, Dried Fermentation Biomass (DFB), Peptone 50, PEP2+, and fish meal.

Table 2. Standardized ileal digestibility (SID, %) of CP and AA in soybean meal, Dried Fermentation Biomass (DFB), Peptone 50, PEP2+, and fish meal by weanling pigs

^a-cValues within a row lacking a common superscript letter are different (P < 0.05).

This research report is based on unpublished research by R. C. Sulabo and H. H. Stein.