Table 1.

Models of NEC and associated phenotypes. Most significant resource requirements and some significant aspects of NEC pathogenesis learned from these models are listed.

Animal Model	Phenotype	Resources	Examples of specific questions answered with each model
Rat	• Sloughing of epithelial cells at tips of villi • Attenuation of normal developmental increase in heart rate variability • Increased serum levels of proinflammatory cytokines (e.g., IL-1B, IL-6)	• Low cost • Easy breeding • Limited availability of transgenic models	• Role of probiotics in NEC prevention93 • Therapeutic applications of anti-TNF-alpha antibody94 • Protective effect of antioxidants95 • Correlation of intestinal fatty acid binding protein on timing of NEC onset96 • Role of protein kinase A inhibitor as a potential therapy in experimental NEC 97
Mouse	• Ileum is scattered with patchy lesions of injury • Tissue destruction ranging from mild destruction to the tips of villi to transmural necrosis • Upregulation of inflammatory factors and antimicrobial peptides (e.g., IL1-B, Cxcl2, Reg3g)	• Low cost • Easy breeding • Able to create transgenic models	• The role of TLR4 in the pathogenesis of NEC30 • Therapeutic potential of short-chain fatty acids in alleviating intestinal inflammation in NEC98 • Impact of human milk oligosaccharides on experimental NEC 99
Piglet	• Severe abdominal distension • Hemorrhagic discoloration and sloughing throughout small and large bowel • Necrosis and sloughing of epithelium	• High cost • Limited availability of transgenic models	• Role of nitric oxide production in the pathogenesis of NEC100 • Diagnostic applications of transabdominal near infra-red spectroscopy101 • Impact of NEC on hippocampal development 98 • Impact of abrupt versus gradual advancement of enteral feeds on the incidence of NEC81 • Potential of probiotics in lowering the incidence of NEC 102