title: Orally administered whole egg demonstrates antidepressant-like effects in the forced swimming test on rats.
abstract: OBJECTIVE
  Several studies have reported that vegetarian diets are associated with a higher prevalence of major depression. Therefore, we hypothesised that the consumption of animal products, especially eggs, may have positive effects on mental health, especially on major depression, because a previous study reported that egg consumption produces numerous beneficial effects in humans. The purpose of the present study was to evaluate the effects of chronic whole-egg treatment on depression-like behaviours in Wistar rats, a control strain, and Wistar Kyoto rats, an animal model of depression.
  
  
  METHODS
  In both the rats, either whole-egg solution (5 ml/kg) or distilled water (5 ml/kg) was orally administrated for 35 days. During these periods, the open-field test (OFT) was conducted on the 21st day, and a forced swimming test (FST) was enforced on the 27th and 28th days. On the 36th day, the plasma and brain were collected.
  
  
  RESULTS
  Chronic whole-egg treatment did not affect line crossing in the OFT, whereas it reduced the total duration of immobility in the FST on both strains. Furthermore, interestingly, the results indicated the possibility that whole-egg treatment elevated the incorporation of tryptophan into the brain, and the tryptophan concentration in the prefrontal cortex was actually increased by the treatment.
  
  
  CONCLUSIONS
  This study demonstrated that whole-egg treatment exerts an antidepressant-like effect in the FST. It is suggested that whole egg may be an excellent food for preventing and alleviating the conditions of major depression.
authors.affiliation: Laboratory of Regulation in Metabolism and Behavior,Graduate School of Bioresource and Bioenvironmental Sciences,Kyushu University,Fukuoka,Japan.
authors.forename: Mao
authors.initials: M
authors.lastname: Nagasawa
authors.affiliation: Laboratory of Regulation in Metabolism and Behavior,Graduate School of Bioresource and Bioenvironmental Sciences,Kyushu University,Fukuoka,Japan.
authors.forename: Tsuyoshi
authors.initials: T
authors.lastname: Otsuka
authors.affiliation: Laboratory of Regulation in Metabolism and Behavior,Graduate School of Bioresource and Bioenvironmental Sciences,Kyushu University,Fukuoka,Japan.
authors.forename: Yumi
authors.initials: Y
authors.lastname: Ogino
authors.affiliation: Laboratory of Regulation in Metabolism and Behavior,Graduate School of Bioresource and Bioenvironmental Sciences,Kyushu University,Fukuoka,Japan.
authors.forename: Junki
authors.initials: J
authors.lastname: Yoshida
authors.affiliation: Laboratory of Regulation in Metabolism and Behavior,Graduate School of Bioresource and Bioenvironmental Sciences,Kyushu University,Fukuoka,Japan.
authors.forename: Shozo
authors.initials: S
authors.lastname: Tomonaga
authors.affiliation: Laboratory of Regulation in Metabolism and Behavior,Graduate School of Bioresource and Bioenvironmental Sciences,Kyushu University,Fukuoka,Japan.
authors.forename: Shinobu
authors.initials: S
authors.lastname: Yasuo
authors.affiliation: Laboratory of Regulation in Metabolism and Behavior,Graduate School of Bioresource and Bioenvironmental Sciences,Kyushu University,Fukuoka,Japan.
authors.forename: Mitsuhiro
authors.initials: M
authors.lastname: Furuse
mesh_terms: D000818:Animals; D000928:Antidepressive Agents / Q000008:administration & dosage / Q000627:therapeutic use*; D003863:Depression / Q000178:diet therapy*; D004195:Disease Models, Animal; D004531:Eggs; D008297:Male; D009043:Motor Activity / Q000187:drug effects; D017397:Prefrontal Cortex / Q000187:drug effects / Q000378:metabolism; D051381:Rats; D011921:Rats, Inbred WKY; D017208:Rats, Wistar; D012701:Serotonin / Q000378:metabolism; D013315:Stress, Psychological; D013550:Swimming; D014364:Tryptophan / Q000378:metabolism
chemical_list: D000928:Antidepressive Agents; D012701:Serotonin; D014364:Tryptophan