A porcine animal model to mimic the restart of enteral nutrition (refeeding-model)

ABSTRACT

With the aim towards establishing an animal model of total parenteral nutrition (TPN), 12 piglets aged 9 weeks (mean body weight 21 kg) were surgically provided with central venous catheters. Six piglets were nourished parenterally with the objective to reach a 14-d period of TPN; the other six piglets served as control and were fed normally. Only one animal from each group could be monitored over the whole period. Nine piglets were euthanised on d 13 and one on d 12. No animal showed fever or signs of septicaemia during the study. The levels of Ca, Mg, Na and P in the blood were within the normal range as were those for blood glucose and plasma creatinine. Symptoms of the TPN included: transient diarrhoea, occasional appearance of faecal blood and occasional absence of defecation. A reduced small intestine length and altered mucosal morphology and function were observed. One animal showed bile stasis at the end of the study. All TPN animals showed a remarkably high level of blood urea early in the morning. The intestinal symptoms observed may resemble the human situation during TPN. However, due to the fast growth rate, pigs aged 9 weeks have higher nutrient requirements per kg body weight. Consequently, the osmolality of the nutrient solution was necessarily high. Whether the significantly higher blood urea observed in the TPN group reflected a catabolic metabolism during the starving period at night-time could not be conclusively shown. Alternatively, it could reflect a slower growth rate and a resulting quantitative excess of amino acids (AA), or could have been the consequence of a suboptimal AA composition. A permanent infusion would be favourable in order not to overcharge the capacity for glucose uptake and amino acid metabolism during the infusion.

KEYWORDS:

• Amino acids
• infusion
• osmolality
• parenteral nutrition
• pigs

Acknowledgments

This study was only possible with the help of numerous student assistants, doctoral students, technical assistants and several postdocs. Our sincere thanks go to Sara Altmeyer, Lisa Brucker, Sandra Fischer, Lukasz Grześkowiak, Carolin Heide, Susan Kröger, Beatriz Martinez Vallespin, Jonathan Riedmüller, Ilen Röhe, Robert Pieper, Eva-Maria Saliu and Alina Zetzsche.

Disclosure statement

No potential conflict of interest was reported by the authors.