An industry survey and animal experiment were conducted to evaluate compositional variability and DE and ME content of animal protein byproducts and to generate equations to predict DE and ME content based on chemical analysis. For the 220 samples collected, the greatest concentration of CP was observed in blood meal (BM) and the least in meat and bone meal (MBM) and the greatest concentration of ether extract was in meat meal and the least in BM, with ash content greatest in MBM and least in BM, with Ca and P levels being 36.1 and 16.3% of the ash content, respectively. For the balance experiment, a corn–soybean meal basal diet was used with test diets formulated by mixing 80% of the basal diet with 20% of the animal protein byproduct, except for BM, which was included at 10 and 20% of the test diets. Ten groups of 24 gilts (92.5 ± 7.4 kg final BW) were randomly assigned to the test or basal diet within each group, resulting in 16 replications per animal protein byproduct or basal diet, except for BM determinations (20 replications). Gilts were placed in metabolism crates and offered 2.4 kg daily of their assigned diet for 13 d, with total collection of feces and urine during the last 4 d. Gross energy in the diets, feces, and urine was used to calculate the DE and ME content of each ingredient by the difference procedure, using DE and ME of the basal diet as a covariate among groups of pigs. The DE content of the animal protein byproducts ranged from 5,367 to 2,567 kcal DE/kg DM, and ME ranged from 4,783 to 2,340 kcal ME/kg DM. Using all animal protein byproducts, the best-fit equations were as follows: DE (kcal/kg DM) = −2,468 + (1.26 × GE, kcal/kg DM), with R2 of 0.84, SE = 390, and P < 0.01, and ME (kcal/kg DM) = −2,331 + (1.15 × GE, kcal/ kg DM), with R2 of 0.86, SE = 327, and P < 0.01. The apparent total tract digestibility (ATTD) of Ca and P were also determined using the difference procedure, with the average ATTD of Ca and P for the animal protein byproducts, excluding BM and feather meal, being 27.1 and 39.1%, respectively. These data indicate that DE and ME substantially varied among the animal protein byproducts and sources and that a variety of nutritional components can be used to accurately predict DE and ME for finishing pigs. In addition, it appears that high dietary inclusion rates of animal protein byproducts may result in low ATTD estimates of Ca and P, which may be due to excessive concentrations of total Ca and P affecting digestibility.
Bibliographical noteFunding Information:
This research was financially supported in part by the National Pork Board and Evonik Industries AG. Mention of a trade name, proprietary product, or specific equipment does not constitute a guarantee or warranty by the USDA, the University of Hawaii at Manoa, or the University of Minnesota and does not imply approval to the exclusion of other products that may be suitable. The USDA is an equal opportunity provider and employer.
© 2017 American Society of Animal Science. All rights reserved.
Copyright 2017 Elsevier B.V., All rights reserved.
- Animal protein byproducts
- Apparent total tract digestibility
- Finishing pigs