Dietary Sialyllactose Does Not Influence Measures of Recognition Memory or Diurnal Activity in the Young Pig

Abstract

Sialic acid (SA) is an integral component of gangliosides and signaling molecules in the brain and its dietary intake may support cognitive development. We previously reported that feeding sialyllactose, a milk oligosaccharide that contains SA, alters SA content and diffusivity in the pig brain. The present research sought to expand upon such results and describe the effects of feeding sialyllactose on recognition memory and sleep/wake activity using a translational pig model. Pigs were provided ad libitum access to a customized milk replacer containing 0 g/L or 380 g/L of sialyllactose from postnatal day (PND) 2–22. Beginning on PND 15, pigs were fitted with accelerometers to track home-cage activity and testing on the novel object recognition task began at PND 17. There were no significant effects of diet on average daily body weight gain, average daily milk intake, or the gain-to-feed ratio during the study (all p ≥ 0.11). Pigs on both diets were able to display recognition memory on the novel object recognition task (p < 0.01), but performance and exploratory behavior did not differ between groups (all p ≥ 0.11). Total activity and percent time spent sleeping were equivalent between groups during both day and night cycles (all p ≥ 0.56). Dietary sialyllactose did not alter growth performance of young pigs, and there was no evidence that providing SA via sialyllactose benefits the development of recognition memory or gross sleep-related behaviors.

Bovine Milk Oligosaccharides with Sialyllactose for Preterm Piglets

“…In this study, we showed that pigs fed SAL and HOS tolerated the experimental diets with no additional adverse effects relative to PRE-CON. The tolerability is in agreement with the literature within this field [ 17 , 47 , 48 , 49 , 50 ]. PRE-SAL pigs, which received oligosaccharides with SL in levels equal to the natural content of 330–880 mg/L in human breast milk [ 51 , 52 , 53 ], in general, did not differ in parameters related to growth, organ weights, microbiota, functional gut parameters and immunity compared to PRE-CON.…”

Sialic Acid and Sialylated Oligosaccharide Supplementation during Lactation Improves Learning and Memory in Rats

“…Neu5Ac brain concentration, expression of two learning associated genes and learning and memory abilities were positively impacted by the Sia supplementation. However, a research team has recently reported two studies in which supplementation with sialyllactose from PN2–PN22 or PN32 in piglets showed no significant effect on recognition memory [ 50 ], but did show a sialic acid increase in hippocampus, prefrontal cortex and corpus callosum [ 51 ].…”

Human and Bovine Milk Oligosaccharides Elicit Improved Recognition Memory Concurrent With Alterations in Regional Brain Volumes and Hippocampal mRNA Expression

“…Pigs were tested on the NOR task using two different delays to assess intermediate and long-term recognition memory. Methods used were adapted from previous studies using this task in pigs from other labs ( Moustgaard et al, 2002 ; Gifford et al, 2007 ; Kornum et al, 2007 ; Kouwenberg et al, 2009 ) and our own ( Fleming and Dilger, 2017 ; Fleming et al, 2017 , 2018 ). Testing consisted of a habituation phase, a sample phase, and a test phase.…”