Early life food insecurity in male rats impairs memory function during adulthood

Approximately 14% of U.S. households are food insecure. The neurocognitive and metabolic impacts of unpredictable food access during early-life periods of development are poorly understood. To address these gaps we devised a novel rat model of food insecurity to control the timing, type, and quantity of accessible food using programmable feeders. Male rats were divided into 3 groups: Secure-chow (SC), a control group given 100% of daily estimated caloric intake, distributed evenly across 4 daily meals of standard chow at set mealtimes; Secure-mixed (SM), a 2nd control group identical to the SC group except that the food type predictably alternated daily between chow and a high-fat, high-sugar diet (HFHS); and Insecure-mixed (IM), the experimental group given randomly alternating daily access to either chow or HFHS at either 85% or 115% of daily estimated caloric intake, distributed evenly across 3 daily meals with unpredictable mealtimes. These feeding schedules were implemented from postnatal days (PNs) 26-45, after which all groups received chow ad libitum. Metabolic assessments performed in adulthood revealed no group differences in caloric intake, body weight, or body composition when maintained on either chow (PN46-149) or a cafeteria diet (PN150-174). Behavioral measures (PN66-126) revealed no group differences in anxiety-like, exploratory, or impulsive behavior (zero maze, open field, differential reinforcement of low rates of responding procedures). However, the IM group exhibited hippocampus-dependent memory impairments compared to both control groups in the novel location recognition test. These findings suggest that early-life food insecurity may contribute to long-term impairments in memory function.