Table 1.

Endogenous antimicrobial peptides in food animals.

Species	Antimicrobial peptide	Mode of action	Endogenous source
Porcine	Cathelicidin—Proline-Arginine-39 (PR-39)	Block the recruitment of neutrophils through the inhibition of ubiquitin proteasome-mediated IkBα degradation on endothelial cells	Intestinal cells, bone marrow, lymphoid tissues, and leukocytes
	β-Defensins	Creating pores on the microbial membrane surface to increase cellular permeability	Tissues and cells of the immune system
	Creopins	Modulate membrane permeability by forming partially selective ion channels, or binding to negatively charged membrane lipids to form a closely packed layer that renders membranes permeable	Small intestine
Bovine	Cathelicidins (synthetic endogenous-source)—Bovine myeloid antimicrobial peptides (BMAPs), Bac2A, and IDR-1018	Antibacterial activity against pathogens	Different tissues of the body and milk
	β-Defensin—Tracheal antimicrobial peptide (TAP)	Prevent infection at the respiratory mucosal surfaces through bactericidal activities	Epithelial cells lining the respiratory tract and other mucosal surfaces
Poultry	Cathelicidins, namely chCATH-1, −2 −3 (also called fowlicidin-1, −2 and −3),	Exert antibacterial activity by serving as a chemo-attractant to neutrophils, without affecting the migration of monocytes or lymphocytes	Lymphoid tissues in chickens
	β-Defensins—AvBD1 toAvBD14	Provides broad-spectrum antimicrobial activity	Expressed in various tissues, including the reproductive organs, bone marrow, respiratory tract, skin, digestive tract, and in cells like heterophils
	Ovodefensins	Antibacterial activity against E. coli and S. aureus	Expressed throughout the chicken oviduct
	Gallin	Antibacterial activity against E. coli	Found in egg albumen
Fish	Piscidins	Bacteriostatic—inhibit further growth and development of pathogens by penetrating and destroying the spores	Various tissues in the fish
	β-Defensins	Contributes to antimicrobial activity in phagocytes	Various tissues in the fish
	Cathelicidin	Antibacterial	Embryonic tissue in fish
	Hepcidins—Hemp1 and Hemp2	Increase resistance to microbial infection by preventing the release of iron from macrophages, and preventing the absorption of iron in the small intestine	Predominantly expressed in the liver of adult fish
	Histone-derived peptides	Broad-spectrum antibacterial activity	In Fish