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

An experiment was conducted to measure the apparent total tract digestibility (ATTD) and standardized total tract digestibility (STTD)  of phosphorus in Dried Fermentation Biomass, Peptone 50, PEP2+, and fish meal fed to weanling pigs.

A total of 40 weanling barrows were fed one of five diets. The four experimental diets were formulated by mixing cornstarch and sugar with Dried Fermentation Biomass, Peptone 50, PEP2+, or fish meal. The fifth diet was a phosphorus-free diet that was used to measure basal endogenous loss of phosphorus. Pigs were fed at three times their maintenance energy requirement. Fecal materials were collected over a five-day period following a seven-day adaptation period to the diet.

Apparent total tract digestibility of phosphorus in each diet was calculated by subtracting fecal phosphorus output from phosphorus intake to determine the amount of phosphorus absorbed by the pig, then dividing that amount by the phosphorus intake. Because the experimental ingredients were the only sources of phosphorus in the diets, the calculated digestibility values for each diet also represents the ATTD of phosphorus in each ingredient. These values were then corrected for the basal endogenous loss of phosphorus that was measured from pigs fed the phosphorus-free diet (148 mg/kg DMI) to calculate the standardized total tract digestibility of phosphorus for each ingredient.

The analyzed total phosphorus concentration in fish meal (3.25%) was roughly four times greater than in Dried Fermentation Biomass, PEP2+, and Peptone 50 (0.88, 0.80, and 0.74%, respectively).  Pigs fed Dried Fermentation Biomass consumed less (P < 0.05) feed daily on average than those fed the other dietary treatments (Table 1). Daily phosphorus intake was greatest (P < 0.001) in pigs fed fish meal and least in pigs fed Dried Fermentation Biomass and Peptone 50, with PEP2+ being intermediate.

Pigs fed fish meal excreted the greatest (P < 0.001) concentration and total amount of phosphorus in feces, followed by pigs fed Peptone 50, and finally by pigs fed either Dried Fermentation Biomass or PEP2+.

Both ATTD and STTD of phosphorus were greatest (P < 0.001) in Dried Fermentation Biomass and PEP2+. The ATTD of phosphorus in Peptone 50 and fish meal did not differ, while the STTD of phosphorus was greater (P < 0.001) in Peptone 50 than in fish meal. Although phosphorus digestibility was least in fish meal, the relatively high phosphorus concentration in that ingredient meant that pigs fed fish meal absorbed the greatest (P < 0.001) amount of phosphorus daily. Pigs fed PEP2+ absorbed the second highest amount of phosphorus daily, followed by pigs fed Dried  Fermentation Biomass, and finally pigs fed Peptone 50.

• Phosphorus digestibility was greater in Dried Fermentation Biomass, PEP2+, and Peptone 50 than in fish meal.
• The greater digestibility of phosphorus in Dried Fermentation Biomass, PEP2+, and Peptone 50 compared with fish meal will result in less phosphorus being excreted in the manure of pigs if these ingredients are used rather than fish meal.
• Due to their relatively low concentrations of phosphorus, Dried Fermentation Biomass, PEP2+, and Peptone 50 provide less digestible phosphorus per kg ingredient than fish meal.
• Using Dried Fermentation Biomass, PEP2+, or Peptone 50 to replace fish meal in nursery pig diets will require greater phosphorus supplementation either from an inorganic source or from other ingredients with high phosphorus content. 

Table 1. Apparent total tract digestibility (ATTD) and standardized total tract digestibility (STTD) of P in Dried Fermentation Biomass (DFB), Peptone 50, PEP2+, and fish meal fed to weanling pigs¹

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

¹EPL = endogenous phosphorus loss. This value was measured from pigs fed the P-free diet at 148 mg/kg dry matter intake (DMI). The daily basal EPL (mg/d) for each diet was calculated by multiplying the EPL (mg/kg DMI) by the daily DMI of each diet.

This research report is based on unpublished research from the University of Illinois.