The aim of this review article is to provide an overview of the role of pigs as a biomedical model for humans. The usefulness and limitations of porcine models have been discussed in terms of metabolic, cardiovascular, digestive and bone diseases in humans. Domestic pigs and minipigs are the main categories of pigs used as biomedical models. One drawback of minipigs is that they are in short supply and expensive compared with domestic pigs, which in contrast cost more to house, feed and medicate. Different porcine breeds show different responses to the induction of specific diseases. For example, ossabaw minipigs provide a better model than Yucatan for the metabolic syndrome as they exhibit obesity, insulin resistance and hypertension, all of which are absent in the Yucatan. Similar metabolic/physiological differences exist between domestic breeds (e.g. Meishan v. Pietrain). The modern commercial (e.g. Large White) domestic pig has been the preferred model for developmental programming due to the 2- to 3-fold variation in body weight among littermates providing a natural form of foetal growth retardation not observed in ancient (e.g. Meishan) domestic breeds. Pigs have been increasingly used to study chronic ischaemia, therapeutic angiogenesis, hypertrophic cardiomyopathy and abdominal aortic aneurysm as their coronary anatomy and physiology are similar to humans. Type 1 and II diabetes can be induced in swine using dietary regimes and/or administration of streptozotocin. Pigs are a good and extensively used model for specific nutritional studies as their protein and lipid metabolism is comparable with humans, although pigs are not as sensitive to protein restriction as rodents. Neonatal and weanling pigs have been used to examine the pathophysiology and prevention/treatment of microbial-associated diseases and immune system disorders. A porcine model mimicking various degrees of prematurity in infants receiving total parenteral nutrition has been established to investigate gut development, amino acid metabolism and non-alcoholic fatty liver disease. Endoscopic therapeutic methods for upper gastrointestinal tract bleeding are being developed. Bone remodelling cycle in pigs is histologically more similar to humans than that of rats or mice, and is used to examine the relationship between menopause and osteoporosis. Work has also been conducted on dental implants in pigs to consider loading; however with caution as porcine bone remodels slightly faster than human bone. We conclude that pigs are a valuable translational model to bridge the gap between classical rodent models and humans in developing new therapies to aid human health.

Four diets were arranged using a 2 ✕ 2 factorial design with two levels of lignocellulose, a high ‘HF’ or a low level ‘LF’ (acid-detergent fibre (ADF) = 191 v. 155 g/kg), combined with two levels of starch replacing 50 g/kg of digestible fibre (DF = hemicelluloses + pectins), a high starch (low DF) ‘HS’ or a low starch (high DF) level ‘LS’ (starch = 193 v. 123 g/kg). Two trials were conducted to measure digestive efficiency and rate of passage, respectively. A third trial was performed in a network of six French experimental breeding units to measure growth and digestive health on 507 rabbits per diet. Foods were offered ad libitum from weaning to slaughter.

No significant interactions were detected between the effect of the level of lignocellulose and the effect of starch replacement by DF, on rabbit digestion, performance or digestive health. A proportional increase of overall food digestibility (organic matter (OM) or energy) was observed with the decrease of ADF level. When 50 g/kg of DF was replaced by starch we observed a significant improvement of OM and energy digestibility ( + 0·03 units). The whole-tract mean retention time of particles was 21 h. It was significantly longer with a lower ADF level ( + 5·4 h for LF v. HF diets), and it tended to increase when DF was substituted by starch ( + 2·2 h for HS v. LS diets).

Between weaning and slaughter, food intake was mainly affected by the ADF level (139 v. 130 g/day respectively for HF and LF diets) and to a lesser extent by the replacement of DF by starch (136·2 v. 133·4 g/day, respectively for LS and HS diets). The weight gain was only slightly higher for high starch (low DF) diets ( +1 g/day) without an effect of the ADF level.

Between weaning and slaughter, morbidity and mortality rates (from acute diarrhoea) were significantly reduced with high-fibre diets (-6 and -4 units respectively), while the replacement of DF by starch had no significant effect.