Investigating antibiotic free feed additives for growth promotion in poultry: effects on performance and microbiota

Ana Fonseca; Sophia Kenney; Emily Van Syoc; Stephanie Bierly; Francisco Dini-Andreote; Justin Silverman; John Boney; Erika Ganda

doi:10.1016/j.psj.2024.103604

Investigating antibiotic free feed additives for growth promotion in poultry: effects on performance and microbiota

Poult Sci. 2024 May;103(5):103604. doi: 10.1016/j.psj.2024.103604. Epub 2024 Mar 4.

Authors

Ana Fonseca¹, Sophia Kenney¹, Emily Van Syoc², Stephanie Bierly¹, Francisco Dini-Andreote³, Justin Silverman⁴, John Boney⁵, Erika Ganda⁶

Affiliations

¹ Department of Animal Science, The Pennsylvania State University, University Park, PA, USA; One Health Microbiome Center, The Pennsylvania State University, University Park, PA, USA.
² Department of Animal Science, The Pennsylvania State University, University Park, PA, USA; One Health Microbiome Center, The Pennsylvania State University, University Park, PA, USA; Department of Biology, The Pennsylvania State University, University Park, PA, 16802, USA.
³ One Health Microbiome Center, The Pennsylvania State University, University Park, PA, USA; Department of Plant Science and Huck Institutes of the Life Sciences, The Pennsylvania State University, University Park, PA, USA.
⁴ One Health Microbiome Center, The Pennsylvania State University, University Park, PA, USA; College of Information Sciences and Technology, The Pennsylvania State University, University Park, PA, USA; Department of Statistics, The Pennsylvania State University, University Park, PA, USA; Department of Medicine, The Pennsylvania State University, University Park, PA, USA; Institute for Computational and Data Science, The Pennsylvania State University, University Park, PA, USA.
⁵ Department of Animal Science, The Pennsylvania State University, University Park, PA, USA.
⁶ Department of Animal Science, The Pennsylvania State University, University Park, PA, USA; One Health Microbiome Center, The Pennsylvania State University, University Park, PA, USA. Electronic address: ganda@psu.edu.

Abstract

The poultry industry is evolving towards antibiotic-free production to meet market demands and decelerate the increasing spread of the antimicrobial resistance. The growing need for antibiotic free products has challenged producers to decrease or completely stop using antimicrobials as feed supplements in broiler diet to improve feed efficiency, growth rate, and intestinal health. Natural feed additives (e.g., probiotics and phytobiotics) are promising alternatives to substitute antimicrobial growth promoters. The goal of our study was to characterize the effects of a Probiotic and an Essential Oils blend on broilers' performance and perform a time-series analysis to describe their excreta microbiome. A total of 320 Cobb 500 (1-day-old) chicks were raised for 21 d in 32 randomly allocated cages. Treatments consisted of 4 experimental diets: a basal diet, and a basal diet mixed with an Antibiotic (bacitracin methylene disalicylate), an essential oils blend (oregano oil, rosemary, and red pepper), or a Probiotic (Bacillus subtilis). Body weight (on 1, 10, and 21d), and feed intake (10d and 21d) were recorded and feed conversion ratio was calculated. Droppings were collected daily (1-21d) to characterize broilers' excreta microbiota by targeted sequencing of the bacterial 16S rRNA gene. The Probiotic significantly improved feed conversion ratio for starter phase 1 to 10d (P = 0.03), grower phase 10 to 21d (P = 0.05), and total period 1 to 21d (P = 0.01) compared to the Antibiotic. Feed supplements did not affect alpha diversity but did impact microbial beta diversity (P < 0.01). Age also impacted microbiome turnover as differences in alpha and beta diversity were detected. Furthermore, when compared to the basal diet, the probiotic and antibiotic significantly impacted relative abundance of Bifidobacterium (log2 fold change -1.44, P = 0.03), Intestinimonas (log2 fold change 0.560, P < 0.01) and Ligilactobacillus (log2 fold change -1.600, P < 0.01). Overall, Probiotic supplementation but not essential oils supplementation positively impacted broilers' growth performance by directly causing directional shifts in broilers' excreta microbiota structure.

Keywords: broiler; essential oil; microbiome; performance; probiotic.

MeSH terms

Animal Feed* / analysis
Animals
Anti-Bacterial Agents* / administration & dosage
Anti-Bacterial Agents* / pharmacology
Bacillus subtilis / drug effects
Bacitracin / administration & dosage
Bacitracin / pharmacology
Chickens* / growth & development
Chickens* / microbiology
Diet* / veterinary
Dietary Supplements* / analysis
Feces / microbiology
Gastrointestinal Microbiome / drug effects
Male
Microbiota / drug effects
Oils, Volatile* / administration & dosage
Oils, Volatile* / pharmacology
Plant Oils / administration & dosage
Plant Oils / pharmacology
Probiotics* / administration & dosage
Probiotics* / pharmacology
Random Allocation
Salicylates*

Substances

Oils, Volatile
Anti-Bacterial Agents
bacitracin methylenedisalicylic acid
Bacitracin
rosemary oil
Plant Oils
Salicylates