Changes in Fatty Acid Dietary Profile Affect the Brain–Gut Axis Functions of Healthy Young Adult Rats in a Sex-Dependent Manner

Abstract

Dietary modifications, including those affecting dietary fat and its fatty acid (FA) composition, may be involved in the development of brain–gut axis disorders, with different manifestations in males and females. Our aim was to evaluate the impact of three purified diets with different FA composition on the brain–gut axis in rats of both sexes. Male and female Wistar rats fed a cereal-based standard diet from weaning were used. At young adult age (2–3 months old), animals were divided into three groups and treated each with a different refined diet for 6 weeks: a control group fed on AIN-93G diet containing 7% soy oil (SOY), and two groups fed on AIN-93G modified diets with 3.5% soy oil replaced by 3.5% coconut oil (COCO) or 3.5% evening primrose oil (EP). Different brain–gut axis parameters were evaluated during 4–6 weeks of dietary intervention. Compared with SOY diet (14% saturated FAs, and 58% polyunsaturated FAs), COCO diet (52.2% saturated FAs and 30% polyunsaturated FAs) produced no changes in brain functions and minor gastrointestinal modifications, whereas EP diet (11.1% saturated FAs and 70.56% polyunsaturated FAs) tended to decrease self-care behavior and colonic propulsion in males, and significantly increased exploratory behavior, accelerated gastrointestinal transit, and decreased cecum and fecal pellet density in females. Changes in FA composition, particularly an increase in ω-6 polyunsaturated FAs, seem to facilitate the development of brain–gut axis alterations in a sex-dependent manner, with a relatively higher risk in females.

Radiographic assessment of the impact of sex and the circadian rhythm-dependent behaviour on gastrointestinal transit in the rat

“…To our knowledge, no previous study has specifically evaluated the influence of sex on gastrointestinal transit using radiographic methods in rodents. In the few radiographic studies in which females were used, results from animals of both sexes were either combined [24][25][26][27][28] or evaluated separately without a specific comparison 29 and methodological differences (including animal species) preclude proper comparison with our results. In the present study, the F-N transit curves were similar to those of M-N from the moment of barium administration (T0) until T8 for all regions, but from this point until T24 gastrointestinal transit was delayed in F-N.…”

Effects of Commercial Probiotics on Colonic Sensitivity after Acute Mucosal Irritation

“…Finally, our study has allowed us to obtain a first approximation to the effects of Actimel ® on visceral pain and immunocytes in young adult males. Nevertheless, in the last years, it has been demonstrated that males and females do not behave in the same way in visceral pain experiments [ 18 , 20 ], and also different responses may be found in animals of different ages. Since abdominal pain is a highly prevalent condition irrespective of sex and age, and Actimel ® is also a popular commercial product, further research investigating the influence of these factors (sex and age) is warranted.…”

“…The number of mast cells stained with toluidine blue [ 20 ] was counted under a 40× objective in ten fields per colonic sample all along the area between the epithelium and external muscular layer.…”

Evaluation of the Effects of Instant Cascara Beverage on the Brain-Gut Axis of Healthy Male and Female Rats

“…The splash test is a behavioral assay aimed at detecting a possible state of anhedonia in rodents. The splash test was performed, as described by Jacenik et al 2021 [ 27 ]: a 10% sucrose solution was sprayed on the back of the animal, which responded with a grooming behavior. Grooming includes nose and face stroking (e.g., stroking along the snout), head grooming (e.g., semicircular movements of the paws over the top of the head and behind the ears), and body grooming (licking the body fur).…”