Growth and hepatic composition in the guinea pig after long-term parenteral hyperalimentation.
This study examined the feasibility of maintaining male Hartley guinea pigs on long-term hyperalimentation. Data from animals fed ad libitum, but infused with 0.9% saline, indicated that there was minimal effect from catheter implantation, sepsis, or the infusion of large volumes of fluid. This group compared with animals fed and watered ad libitum demonstrated a nearly identical growth rate (6.33 +/- 1.18 and 6.12 +/- 1.32 g/day, respectively), serum chemistry, tissue weights, and hepatic composition and morphology. Animals infused with a total parenteral diet demonstrated growth rates of 4.06 +/- 1.46 g/day for up to 25 days. Loss of infused animals was due in varying degrees to sepsis, mechanical failure, improper placement of the cannula, loss of patency, and death from unknown causes. Morphological analysis of animals fed by total parenteral nutrition revealed an altered distribution and increased size of lipid droplets in hepatic parenchymal and Kupffer cells and glycogen accumulation by the parenchymal cells. Decreased hepatic content of total protein and lipid, as well as cytochrome P450, was also observed. Similarly, serum values of triglyceride were decreased in animals fed by the total parenteral diet. This study indicated that the guinea pig fed by hyperalimentation may be a useful animal model for a number of clinical and basic research applications.