The Aachen Minipig: Phenotype, Genotype, Hematological and Biochemical Characterization, and Comparison to the Göttingen Minipig.

BACKGROUND: The pig is one of the most frequently used large animal models for biomedical research, especially in the field of translational research and surgical models. While standard livestock breeds are used in short-term and acute studies, minipig breeds are the preferred breeds in long-term and chronic studies due to their limited growth and body weight.
OBJECTIVE: In consideration of the 3R principle (refinement, reduction, replacement) and the increasing demand, the aim of this study was to generate a new, robust, non-specific-pathogen-free minipig breed, the Aachen minipig.
METHODS: Phenotype, genotype, and hematological as well as clinical chemistry parameters were characterized, and reference values of the Aachen minipig were generated and compared to the values in the commonly used Göttingen minipig. Organ weights of the heart, kidney, liver, lung, spleen, and brain were determined using a laboratory balance. Blood samples were collected for hematology and clinical chemistry. Assessment of genetic diversity was performed by microsatellite markers. Nasal swabs were collected from 11 individual minipigs representing 6 races for DNA extraction. DNA was quantified and the identity and origin of the Aachen minipigs at the genomic level was determined by microsatellites.
RESULTS: The Aachen minipig established here is based on the Mini-LEWE breed and consists of the Vietnamese potbelly pig, the Schwäbisch Hällisch Landpig, the German Landrace, and the Minnesota minipig. Relative organ weights (lung, heart, kidneys, brain), hematology (hemoglobin, hematocrit, platelet count, mean corpuscular hemoglobin concentration, segmented neutrophils, lymphocytes, eosinophils, basophils), and clinical chemistry parameters (sodium, calcium, chloride, alkaline phosphatase, aspartate aminotransferase, alanine aminotransferase, gamma-glutamyl transferase, lactate dehydrogenase, triglycerides, blood urea nitrogen, creatinine, total bilirubin, total protein, creatine kinase) of the Aachen minipigs and the Göttingen minipigs were not significantly different. Significant differences where only seen in relative organ weights (liver, spleen), hematology (red blood cell count, mean corpuscular volume, mean corpuscular hemoglobin, white blood cell count, banded neutrophils, monocytes), and clinical chemistry parameters (inorganic phosphorus, potassium, glucose, cholesterol, albumin, amylase).
CONCLUSION: The Aachen minipig is a suitable model for research due to its similarity to other minipig breeds, especially the Göttingen minipig. The reference values established in this study may be used for the comparison of scientific data and encourage the use of the Aachen minipig as an animal model for biomedical research.