Climate
PAP Nutritional Studies at Wageningen University
Case Study 4
PAPs offer a nutritious, more sustainable feed ingredient for pig a poultry diets.

EFPRA commissioned two nutritional studies at Wageningen University to investigate the benefits of using Processed Animal Proteins (PAPs) in poultry and pig diets — obtaining up-to-date nutrient content and digestibility values for these products.
The poultry and pig feeding trials showed PAP based meals are highly palatable, digestible, nutritious and contain a variety of minerals, such as calcium and phosphorus for strong bones and growth development. The studies showed animal welfare benefits too with reduced feather picking and drier litter observed. Inclusion of our up-todate values for nutrient content and digestibility of PAP in feed comparison tables allows for their optimal use in poultry and pig diets.
The Poultry Study
The poultry feeding trial was designed to rigorously assess the nutritional performance of porcine PAPs in broiler diets, examining both digestibility and real-world growth outcomes.
Study Objectives
  • Determine the precaecal and total tract nutrient digestibility of porcine protein meal
  • Assess the effect of porcine meal on performance, litter quality, bone quality and gut health in male broilers
What the Research Found
The birds performed well across both the digestibility study and the growth performance study. Analysed data revealed meaningful differences between birds fed PAP-supplemented diets and those on the control diet — particularly in litter scores and overall condition.
Processing Method Matters
Differences in processing method were found to affect the nutritional value of PAPs, highlighting the importance of production technique.
Soybean Meal Replacement
Replacement of soybean meal by PAPs is possible without compromising performance, litter quality, footpad lesions, gait score, blood parameters, gut integrity, or bone quality.
Animal Welfare Gains
Reduced feather picking and drier litter were observed in PAP-fed flocks, indicating tangible welfare improvements alongside nutritional benefits.
The Pig Study
A further study examined the nutrient composition, ileal and total tract digestibility, and nutritional value of poultry-based PAPs in growing pigs — providing new, up-to-date data for use in practical feed formulation.
Products Investigated
Poultry Meal
High digestible protein content, exceeding values previously listed for PAPs of unspecified animal origin.
Blood Meal
Among the highest protein digestibility values recorded in the study, making it a highly efficient protein source.
Feather Meal
Protein digestibility at the lower end of the range, at approximately 60%, reflecting its more fibrous composition.
Key Findings
The study provided new data on digestibility and nutritional value for the use of poultry-based PAPs in pig diets specifically poultry meal, blood meal and feather meal. It indicated that the protein digestibility of these products may vary from 60% for feathermeal up to 90%
References & Further Reading
Both studies were conducted at Wageningen University and are available in full. They form part of EFPRA's ongoing commitment to evidence-based sustainability in the rendered products sector.
1
Poultry Study — August 2019
Nutrient digestibility of processed animal proteins in broilers
Wageningen University, August 2019
2
Pig Study — January 2020
Nutritional value of poultry by-products in pig diets
Wageningen University, January 2020
Case Study 4
Version 1, October 2021
Next: Case Study 5