Influence of Rearing Environment on Longitudinal Brain Development, Object Recognition Memory, and Exploratory Behaviors in the Domestic Pig (Sus scrofa)

IntroductionOver the last 40 years, the domestic pig has emerged as a prominent preclinical model as this species shares similarities with humans with regard to immunity, gastrointestinal physiology, and neurodevelopment. Artificial rearing of pigs provides a number of advantages over conventional rearing (i.e., true maternal care), including careful control of nutrient intake and environment conditions. Yet there remains a gap in knowledge when comparing brain development between sow-reared and artificially reared domestic pigs. Thus, our research sought to model brain development and assess recognition memory in a longitudinal manner by directly comparing rearing environments.MethodsForty-four intact (i.e., not castrated) male pigs were artificially reared or sow-reared from postnatal day 2 until postnatal week 4. After postnatal week 4, all pigs were housed in a group setting within the same environment until postnatal week 24. Magnetic resonance imaging was conducted on pigs at 8 longitudinal time-points to model developmental trajectories of brain macrostructural and microstructural outcomes. Additionally, pigs behavior were tested using the novel object recognition task at postnatal weeks 4 and 8.ResultsThroughout the 24-week study, no differences between rearing groups were noted in weekly body weights, average growth and feed intake patterns, or feed efficiency. Whole brain, gray matter, white matter, and cerebrospinal fluid growth patterns also did not differ between pigs assigned to different early-life rearing environments. Moreover, minimal differences in regional absolute volumes and fractional anisotropy developmental trajectories were identified, though artificially reared pigs exhibited higher initial rates of myelination in multiple brain regions compared with sow-reared pigs. Furthermore, behavioral assessment at both PNW 4 and 8 suggested little influence of rearing environment on recognition memory, however, an age-dependent increase in object recognition memory was observed in the sow-reared group.ConclusionOur findings suggest that early-life rearing environment influences the rate of development in some brain regions but has little influence on overall brain growth and object recognition memory and exploratory behaviors in the domestic pig. Artificial rearing may promote maturation in certain brain areas but does not appear to elicit long-term effects in outcomes including brain structure or object recognition memory.

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Rearing Environment and Longitudinal Brain Development in the Pig

Current Developments in Nutrition ◽

10.1093/cdn/nzab049_016 ◽

2021 ◽

Vol 5 (Supplement_2) ◽

pp. 903-903

Author(s):

Joanne Fil ◽

Sangyun Joung ◽

Courtney Hayes ◽

Ryan N Dilger

Keyword(s):

Object Recognition ◽

Recognition Memory ◽

Brain Development ◽

Early Life ◽

Developmental Trajectories ◽

Growth Patterns ◽

Group Setting ◽

Artificial Rearing ◽

Average Growth ◽

Rearing Environment

Abstract Objectives Artificial rearing of pigs provides a number of advantages over conventional rearing (i.e., true maternal care), including careful control of nutrient intake and environment conditions. Yet there remains a gap in knowledge when comparing brain development between sow-reared and artificially-reared domestic pigs. Thus, our research sought to model brain development and assess recognition memory in a longitudinal manner by directly comparing rearing environments. Methods Forty-four intact (i.e., not castrated) male pigs were artificially-reared or sow-reared from postnatal day 2 until postnatal week 4. After postnatal week 4, all pigs were housed in a group setting within the same environment until postnatal week 24. Magnetic resonance imaging was conducted on pigs at 8 longitudinal time-points to model developmental trajectories of brain macrostrutural and microstructural outcomes. Additionally, pigs behavior were tested using the novel object recognition task at postnatal weeks 4 and 8. Results Throughout the 24-week study, no differences between rearing groups were noted in weekly body weights, average growth and feed intake patterns, or feed efficiency. Whole brain, grey matter, white matter, and cerebrospinal fluid growth patterns also did not differ between pigs assigned to different early-life rearing environments. Moreover, minimal differences in regional absolute volumes and fractional anisotropy developmental trajectories were identified, though artificially-reared pigs exhibited higher initial rates of myelination in multiple brain regions compared with sow-reared pigs. Furthermore, behavioral assessment at both PNW 4 and 8 suggested little influence of rearing environment on recognition memory, however, an age-dependent increase in object recognition memory was observed in the sow-reared group. Conclusions Our findings suggest that early-life rearing environment has little influence on brain growth trajectories and behavior in the domestic pig. Artificial rearing may promote maturation in certain brain areas but does not appear to elicit long-term effects in outcomes including brain structure or behavior. Funding Sources The study was funded by Société des Produits Nestlé SA.

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Objects as enrichment: Effects of object exposure time and delay interval on object recognition memory of the domestic pig

Applied Animal Behaviour Science ◽

10.1016/j.applanim.2006.10.019 ◽

2007 ◽

Vol 107 (3-4) ◽

pp. 206-217 ◽

Cited By ~ 27

Author(s):

Amanda K. Gifford ◽

Sylvie Cloutier ◽

Ruth C. Newberry

Keyword(s):

Object Recognition ◽

Recognition Memory ◽

Exposure Time ◽

Delay Interval ◽

Domestic Pig ◽

Object Recognition Memory

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Low‐intensity physical training recovers object recognition memory impairment in rats after early‐life induced Status epilepticus

International Journal of Developmental Neuroscience ◽

10.1016/j.ijdevneu.2013.01.002 ◽

2013 ◽

Vol 31 (3) ◽

pp. 196-201 ◽

Cited By ~ 8

Author(s):

Sandro Daniel Córdova ◽

Cássio Morais Loss ◽

Diogo Losch Oliveira

Keyword(s):

Status Epilepticus ◽

Object Recognition ◽

Recognition Memory ◽

Physical Training ◽

Early Life ◽

Memory Impairment ◽

Low Intensity ◽

Object Recognition Memory

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Chemogenetic silencing of hippocampus and amygdala reveals a double dissociation in periadolescent obesogenic diet-induced memory alterations

10.1101/2020.07.20.212258 ◽

2020 ◽

Cited By ~ 1

Author(s):

Fabien Naneix ◽

Ioannis Bakoyiannis ◽

Marianela Santoyo-Zedillo ◽

Clémentine Bosch-Bouju ◽

Gustavo Pacheco-Lopez ◽

...

Keyword(s):

Object Recognition ◽

Recognition Memory ◽

Basolateral Amygdala ◽

Memory Deficits ◽

Ventral Hippocampus ◽

Brain Regions ◽

Obesity Prevalence ◽

Odor Aversion ◽

Object Recognition Memory

1ABSTRACTIn addition to numerous metabolic comorbidities, obesity is associated with several adverse neurobiological outcomes, especially learning and memory alterations. Obesity prevalence is rising dramatically in youth and is persisting in adulthood. This is especially worrying since adolescence is a crucial period for the maturation of certain brain regions playing a central role in memory processes such as the hippocampus and the amygdala. We previously showed that periadolescent exposure to obesogenic high-fat diet (HFD) had opposite effects on hippocampus- and amygdala-dependent memory, impairing the former and enhancing the latter. However, the causal role of these two brain regions in periadolescent HFD-induced memory alterations remains unclear. Here, we first showed that periadolescent HFD induced long-term, but not short-term, object recognition memory deficits, specifically when rats were exposed to a novel context. Using chemogenetic approaches to inhibit targeted brain regions, we then demonstrated that recognition memory deficits are dependent on the activity of the ventral hippocampus, but not the basolateral amygdala. On the contrary, the HFD-induced enhancement of conditioned odor aversion requires specifically amygdala activity. Taken together, these findings suggest that HFD consumption throughout adolescence impairs long-term object recognition memory through the overactivation of the ventral hippocampus during memory acquisition. Moreover, these results further highlight the bidirectional effects of adolescent HFD on hippocampal and amygdala functions.

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Influence of Dietary Polar Lipid Supplementation on Memory and Longitudinal Brain Development

Nutrients ◽

10.3390/nu13082486 ◽

2021 ◽

Vol 13 (8) ◽

pp. 2486

Author(s):

Joanne E. Fil ◽

Sangyun Joung ◽

Jonas Hauser ◽

Andreas Rytz ◽

Courtney A. Hayes ◽

...

Keyword(s):

Object Recognition ◽

Recognition Memory ◽

Brain Development ◽

Polar Lipid ◽

Early Life ◽

Control Diet ◽

Recognition Task ◽

Polar Lipids ◽

Developmental Patterns ◽

Lipid Supplementation

Polar lipids, which are found in human milk, serve essential functions within biological membranes, hence their importance in brain development and cognition. Therefore, we aimed to evaluate the longitudinal effects on brain macrostructural and microstructural development and recognition memory of early-life polar lipid supplementation using the translational pig model. Twenty-eight intact (i.e., not castrated) male pigs were provided either a control diet (n = 14) or the control diet supplemented with polar lipids (n = 14) from postnatal day 2 until postnatal week 4. After postnatal week 4, all animals were provided the same nutritionally-adequate diets until postnatal week 24. Pigs underwent magnetic resonance imaging at 8 longitudinal time-points to model brain macrostructural and microstructural developmental trajectories. The novel object recognition task was implemented at postnatal weeks 4 and 8 to evaluate recognition memory. Subtle differences were observed between groups in hippocampal absolute brain volumes and fractional anisotropy, and no differences in myelin water fraction developmental patterns were noted. Behavioral outcomes did not differ in recognition memory, and only minimal differences were observed in exploratory behaviors. Our findings suggest that early-life dietary supplementation of polar lipids has limited effect on brain developmental patterns, object recognition memory, and exploratory behaviors.

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