Dietary polydextrose and galactooligosaccharide increase exploratory behavior, improve recognition memory, and alter neurochemistry in the young pig.

OBJECTIVES: Previous studies have shown that dietary prebiotics have the potential to improve memory, alter social behavior, and reduce anxiety-like behaviors in rodents. The present research sought to expand upon such results and describe the effects of feeding prebiotics early in life on cognition and neurochemistry using a translational piglet model.

METHODS: Pigs were provided customized milk replacer containing 2 g/L each of polydextrose (PDX) and galactooligosaccharide (PDX/GOS) or 0 g/L (Control) from postnatal day (PND) 2-33. Beginning on PND 25, pigs were tested on the novel object recognition (NOR), novel location recognition (NLR), and backtest tasks to measure recognition memory and response to restraint stress. At study conclusion pigs were euthanized and intestine, blood, and brain tissues were collected and analyzed.

RESULTS: PDX/GOS-fed pigs demonstrated recognition memory on the NOR task (P < 0.001) whereas Control pigs did not (P = 0.184). Additionally, PDX/GOS-fed pigs visited the novel and sample objects more frequently (all P < 0.05) while spending less time per visit exploring the sample object (P = 0.028) than Control pigs. Volatile fatty acids (VFAs) were decreased in the ascending colon (P < 0.012), whereas butyrate tended to be higher in blood (P = 0.080) and lower in the hippocampus (P = 0.061) of PDX/GOS-fed pigs. PDX/GOS-fed pigs exhibited lower serotonin (P = 0.016) in the hippocampus.

CONCLUSION: These findings suggest that early life consumption of PDX/GOS supports recognition memory as measured by NOR while modulating the concentrations of VFAs in the colon, blood, and brain, as well as hippocampal serotonin.