Porcine Processed Animal Protein can be used as an alternative protein in modern broiler diets without any apparent detrimental effects on the bird’s microbiome, productivity, health and welfare

Background Soybean production is under heavy scrutiny from consumers and other stakeholders due to deforestation associated with soybean cultivation. Broiler chickens depend heavily on soybeans in their diet due to their high protein requirements and soybeans' high bioavailability. Alternative protein sources to soybeans are available; however, the required scale and volume of these alternatives vastly exceed their availability. Porcine Processed Animal Protein (PPAP) has the potential to bridge this gap, but little is known regarding its suitability for broiler nutrition, which is the focus of this study. Methods A multifactorial trial using 840 Ross 308 broilers (as hatched) was conducted, birds were split over six treatments as follows; T1 (Control) a typical Soybean Meal (SBM) based diet, T2 a copy of T1 but with reduced levels of SBM due to 5% PPAP inclusion, T3 a copy of T1 with further reduced levels of SBM and an inclusion of 10% PPAP. T4 was a zero-SBM diet, T5 was a copy of T4 but with the inclusion of 5% PPAP, and T6 was a copy of T4 with the inclusion of 10% PPAP. We monitored bird productivity, health and the caecal microbiome to evaluate the viability of feeding PPAP as an alternative. Results Diets containing SBM performed better than zero-SBM diets in terms of Feed Conversion Ratio (FCR), with trends toward enhanced weight gain, regardless of whether PPAP was used. The use of soybean meal negatively impacted hockburn, however, this is primarily explained by enhanced weight gain. Microbial diversity increased with age across all treatments but did not differ significantly between dietary groups, indicating that PPAP inclusion does not negatively affect gut microbiome development. Functional analysis revealed metabolic adaptations in PPAP-fed birds, including upregulation of fatty acid degradation pathways, suggesting the microbiome maintains metabolic flexibility in response to dietary reformulation. Conclusion To conclude, this work demonstrates that PPAP can be effectively incorporated into broiler diets at 5% or 10% inclusion levels, displacing soybean meal, without causing detrimental effects on broiler health, welfare, or performance. However, the presence or absence of soybean meal is shown to have a greater impact on these parameters, highlighting that the industry should focus on partially replacing soybean rather than completely removing it to improve sustainability.