Maternal protein restriction in the rat during pregnancy and/or lactation alters cognitive and anxiety behaviors of female offspring

Maternal protein deficiencies can developmentally program offspring to lifelong dysfunction of many physiological systems. We hypothesized that maternal isocaloric low protein diet during fetal and early postnatal development would negatively affect female offspring anxiety, exploration, associative learning and motivation as measured by the elevated plus maze (EPM), open field test (OFT), operant conditioning and the progressive ratio task, respectively. Control mothers (C) received a 20% casein diet and restricted mothers (R) a 10% casein diet to provide four groups: CC, RR, CR, and RC (first letter pregnancy diet and second lactation diet) to enable evaluation of offspring effects influenced by maternal diet during pregnancy and lactation. Maternal protein restriction decreased open arm time and distance in RR and RC offspring, increased anxiety behavior, in the EPM. In the OFT, the RR and RC offspring displayed decreased exploration (increased stress) as indexed by decreased distance in the center zone. These behaviors in the EPM and OFT was associated with increased corticosterone levels during an immobilization test in the RR offspring with intermediary effects in the RC offspring. Learning impairment was observed in the RR, CR and RC offspring during fixed ratio 5 schedule of reinforcement. Motivational effects were measured in RR offspring responding less, decreased motivation, and CR offspring making more responses, increased motivation, than CC offspring. These findings reveal the negative effects of developmental protein restriction on female offspring behavior. The underlying basis for these negative outcomes remains to be elucidated.

► In the elevated plus maze, the RR and RC offspring displayed increase anxiety.
► In the open field, the RR and RC offspring displayed increase avoidance.
► Increase avoidance was associated with increased corticosterone levels.
► RR, CR and RC offspring were learning impaired during operant conditioning.
► RR offspring responded less and CR offspring responded more during progressive ratio.