Protein sources of animal origin provide highly digestible protein in diets for weanling pigs. Chicken meal consists primarily of skin, flesh, and sometimes bones from processed birds. Poultry by-product meal contains offal from processed chickens, including  feet, necks, beaks, undeveloped eggs, and intestinal contents. AV-E digest consists of enzymatically hydrolyzed spent hens and extruded egg albumin, mixed with a soybean meal carrier. Ultrapro is produced from enzymatically hydrolyzed porcine intestines, which are used in the production of the drug heparin. There is a lack of data on the concentration of digestible and metabolizable energy in all of these ingredients, which limits their use in diets fed to weanling pigs.

An experiment was conducted to determine the concentrations of digestible and metabolizable energy in chicken meal, poultry by-product meal, Ultrapro, and AV-E digest, and to compare these values with soybean meal.

A total of 48 barrows with an average initial body weight of 14.6kg were used in the experiment. Six corn-based diets were formulated to contain similar concentrations of crude protein. The basal diet contained 98% corn. The experimental diets contained  11% chicken meal, 12% poultry by-product meal, 16% Ultrapro, 16% AV-E digest, and 16% soybean meal, respectively. Corn and the experimental ingredients were the only sources of energy in the diets.

The apparent total tract digestibility of gross energy did not differ among the six animal and plant protein sources tested (Table 2).

On both an as-fed and dry matter basis, poultry by-product meal and Ultrapro had the greatest concentrations of digestible energy, while corn had the least. On an as-fed basis, digestible energy concentrations in chicken meal, AV-E digest, and soybean meal were less than in poultry by-product meal and Ultrapro, and did not differ from each other. On a dry matter basis, digestible energy concentrations in AV-E digest and soybean meal were less than in poultry by-product meal but did not differ from Ultrapro. The concentration of digestible energy in chicken meal was less than in Ultrapro but did not differ from AV-E digest and soybean meal.

Metabolizable energy concentrations were greatest in poultry by-product meal on an as-fed basis. Ultrapro and AV-E digest had metabolizable energy concentrations that were less than poultry by-product meal but did not differ from each other. The concentration of metabolizable energy in soybean meal was less than in AV-E digest, but did not differ from Ultrapro. Chicken meal had less metabolizable energy than Ultrapro, but did not differ from soybean meal. Corn had the least amount of metabolizable energy of all the ingredients tested. On a dry matter basis, poultry by-product meal and Ultrapro had the greatest concentrations of metabolizable energy. Metabolizable energy concentrations in AV-E digest and soybean meal were less than in poultry by-product meal, but did not differ from Ultrapro. Corn and chicken meal had less metabolizable energy than AV-E digest, but did not differ from soybean meal.

• The animal protein sources tested did not differ in energy digestibility from corn or soybean meal.
• Poultry by-product meal and Ultrapro had the greatest concentrations of digestible and metabolizable energy of all ingredients.
• The concentrations of digestible and metabolizable energy in all experimental ingredients are equal to  or greater than in soybean meal, indicating that dietary energy concentrations will not be compromised if these products are used in diets fed to pigs.

Table 1. Analyzed nutrient composition of chicken meal (CM), poultry by-product meal (PBM), Ultrapro, AV-E Digest, and soybean meal (SBM), and corn, as-fed basis

¹AEE = acid hydrolyzed ether extract.

Table 2. Concentration of digestible and metabolizable energy, and apparent total tract digestibility (ATTD) of energy in corn, chicken meal (CM), poultry by-product meal (PBM), Ultrapro, AV-E digest, and soybean meal (SBM)

^a-eMeans within a row lacking a common superscript letter differ (P < 0.05).

This report is based on unpublished data by O. J. Rojas and H.H. Stein.