Effects of early weaning on the circadian rhythm and behavioral satiety sequence in rats

Abstract

The objective of this work was to study the effect of early weaning on circadian rhythm and the behavioral satiety sequence in adult rats. Male Wistar rat pups were weaned for separation from the mother at 15 (D15), 21 (D21) and 30 (D30) days old. Body weight and food intake was measured every 30 days until pups were 150 days old. At 90 days of age, the circadian rhythm of food intake was evaluated every 4h for three days. Behavioral satiety was evaluated at 35 and 100 days of age. This work demonstrated that body weight and food intake were not altered, but the behavioral satiety sequence demonstrated that the D15 group delayed satiety compared with the D30 group at 100 days of age. In the circadian rhythm of the food intake study, early weaning (D15) changed food intake in the intermediary period of the light phase and in the intermediary period of the dark phase. In conclusion, our study showed that early weaning may alter the feeding behavior mainly in relation to satiety and the circadian rhythm of feeding. It is possible that the presence of other environmental stimuli during early weaning can cause hyperphagia and deregulate the mechanisms of homeostasis and body weight control. This study supports theories that depict insults during early life as determinants of chronic diseases.

Brain development in male rats subjected to early weaning and treated with diet containing flour or flaxseed oil after 21 days until 60 days

“…At this age, pups still breastfeed, but they can survive independently of their mothers. 12 However, the precocious interruption of lactation can be a prime factor for behavioral changes, such as higher anxiety, higher motor activity and reduced cognitive performance, which exhibit significant sex dependence. [13][14][15] A limitation of the present study is the fact that we could not evaluate behavior and sex differences in relation to brain development.…”

“…At 14 days of life, rats begin consumption of solid food. At this age, pups still breastfeed, but they can survive independently of their mothers 12 . However, the precocious interruption of lactation can be a prime factor for behavioral changes, such as higher anxiety, higher motor activity and reduced cognitive performance, which exhibit significant sex dependence 13 …”

Body composition in male rats subjected to early weaning and treated with diet containing flour or flaxseed oil after 21 days until 60 days

“…At this age, pups still breastfeed, but they can survive independently of their mothers. 15,17 However, the lack of calories, macro and micronutrients derived from milk were not offset, justifying the lower body parameters observed in the EW21 rats.…”

A Ketogenic & Low-Protein Diet Slows Retinal Degeneration in rd10 Mice

“… 32 , 40 – 42 In addition to activating a stress response, early weaning can delay the triggering of satiety and modulate the circadian rhythm of food intake, which was demonstrated in male Wistar rat pups out to PD100. 43 It is feasible that changes in behavioral satiety and food consumption can impact the retina, because recent studies have linked the gut microbiota with retinal disease. 44 Furthermore, the glucagon-like peptide-1 (GLP-1), which is an incretin hormone secreted by the gastrointestinal tract in response to food, has shown neuroprotective effects for retinal ganglion cells.…”