Intermittent fasting and mental and physical fatigue in obese and non-obese rats

The ameliorating effect of intermittent fasting on intestinal glucagon-like peptide 1 in rats fed a high-fat diet via the Farnesoid X receptor and the Melanocortin-4 receptor

Obesity and its associated intestinal inflammatory responses represent a significant global challenge. (IF) is a dietary intervention demonstrating various health benefits, including weight loss, enhanced metabolic health, and increased longevity. However, its effect on the intestinal inflammation induced by high-fat diet (HFD) is still not fully comprehended. Thirty-four male Sprague-Dawley rats were randomized into three groups: Control (fed standard chow diet for 24 weeks); the HFD group (fed HFD for 24 weeks); and the HFD + IF group (fed HFD for 12 weeks, followed by an alternate day regimen of fasting and HFD for 12 weeks). The results revealed that IF significantly reduced body weight, food intake, and blood glucose levels compared to the HFD group. Furthermore, rats undergoing the intermittent fasting regimen exhibited a significant reduction in resting time, along with increased durations of grooming and exploration when compared to those on HFD. IF significantly reduced HFD-induced intestinal oxidative stress by lowering malondialdehyde levels and substantially increasing intestinal total antioxidant capacity, consistent with histopathological findings of gastric and intestinal tissues. The investigation of the underlying mechanisms revealed that IF significantly increased the intestinal expression of Farnesoid X receptor (FXR), glucagon-like peptide 1 (GLP-1), and melanocortin-4 receptors (MC4R), with a significant decrease in gastrointestinal peroxisome proliferator-activated receptor-γ (PPAR-γ) compared to the HFD group. The findings indicate that IF can mitigate HFD-induced intestinal inflammation via the FXR/GLP-1/MC4R/ PPAR-γ pathway. This highlights the need for further research to elucidate these mechanisms.

6-week time-restricted eating improves body composition, maintains exercise performance, without exacerbating eating disorder in female DanceSport dancers

BACKGROUND

Despite the high risk of eating disorder (ED)-related attitudes and behaviors among female dancers, targeted scientific dietary regimens are currently inadequate. Time-restricted eating (TRE), a popular intermittent fasting protocol, has been shown to be effective in enhancing body composition and exercise performance in athletes. In this study, TRE was employed as a dietary regimen to improve body composition and exercise performance and address ED attitudes and behaviors in DanceSport dancers.

METHODS

Twenty female DanceSport dancers were recruited and divided into two groups: TRE (n = 10) and normal diet (ND) (n = 10). The TRE group consumed their self-selected necessary energy intake exclusively between 11 a.m. and 7 p.m. (utilizing a 16-hour fasting and 8-hour eating window) for 6 weeks, while the ND group maintained their regular dieting patterns. The consumption of water, black tea, or coffee without added sugar or milk was not restricted. Physical activity and calorie intake were systematically recorded during the TRE intervention. Body composition, aerobic and anaerobic performance, and ED attitudes and behaviors were assessed before and after the TRE intervention. The trial was registered in the Chinese Clinical Trial Registry under the identifier ChiCTR2200063780.

RESULTS

The fixed effects tests (p < 0.0001) and estimates for the intercept (p < 0.0001) of hunger level indicated a noticeable effect on the initial state of hunger during TRE. No significant differences were observed in ED attitudes or behaviors (p > 0.05). TRE resulted in a reduction in hip circumference (p = 0.039), fat mass (kg) (p = 0.0004), and body fat percentage (p = 0.0005), with no significant decrease in fat-free mass (p > 0.05). No significant improvement was observed in aerobic performance (p > 0.05). The average power (AP) (p = 0.01) and AP/Body weight ratio (p = 0.003) significantly increased. Additionally, the power drop decreased significantly (p = 0.019). Group-by-time interactions were observed for fat mass (kg) (p = 0.01), body fat percentage (p = 0.035), and AP/Body weight (p = 0.020).

CONCLUSION

TRE can be considered a feasible nutritional strategy for DanceSport dancers, facilitating improvements in body composition without compromising aerobic and anaerobic exercise performance or exacerbating ED attitudes and behaviors. Moreover, TRE may facilitate more favorable physiological adaptations, potentially contributing to improved exercise performance.

Sheep fatigue during transport: Lost in translation?

Although sheep are commonly transported long distances, and sheep welfare during transport is a topic of research and policy discussion, the subject of their fatigue during transport has been under-researched. The current qualitative study, focused on the EU and UK, aimed to critically analyse stakeholder views on issues relating to sheep fatigue, including behavioural indications of fatigue, the interplay between fatigue and other factors, and the practicalities of identifying fatigue in commercial transport conditions. Insight into stakeholder perceptions of these issues could contribute to the body of knowledge regarding sheep fatigue during transport, potentially playing a part in future efforts to improve fatigue understanding and detection. Eighteen experts from different stakeholder groups were interviewed. Reflexive thematic analysis of interview data yielded four themes and three sub-themes. The first theme, "Let's anthropomorphise it a little bit", underscores the pervasiveness of anthropomorphism and suggests using it in a conscious and deliberate way to drive stakeholder engagement and policy change. The second theme, "We think that they're like we are and they're not", cautions against wholesale transfer of human experiences to animals. The third theme, 'See the whole animal', advocates using Qualitative Behaviour Analysis (QBA), proven reliable in other contexts, to deepen and enrich our current understanding of fatigue. The fourth theme, 'Fatigue "never comes up"', highlights the fact that fatigue is rarely if ever discussed in the context of sheep transport. These themes suggest several avenues for future research, including developing QBA-based assessments for fatigue to improve welfare during transport.

Intermittent fasting disrupts hippocampal-dependent memory and norepinephrine content in aged male and female mice

Intermittent fasting (IMF) is associated with many health benefits in animals and humans. Yet, little is known if an IMF diet affects mood and cognitive processing. We have previously identified that IMF in diet-induced obese males increases norepinephrine and dopamine content in the hypothalamus and increases arcuate neuropeptide Y (NPY) gene expression more than in ad libitum control males. This suggests that IMF may improve cognition through activation of the hindbrain norepinephrine neuronal network and reverse the age-dependent decline in NPY expression. Less is known about the association between anxiety and IMF. Although, in humans, IMF during Ramadan may alleviate anxiety. Here, we address the impact of IMF on anxiety-like behavior using the open field test, hippocampal-dependent memory using the Y-maze and spatial object recognition, and hippocampal-independent memory using novel object recognition in middle-aged male and female (12 mo) and aged male and female (18 mo) mice. Using ELISA, we determined norepinephrine (NE) content in the dorsal hippocampus (DH) and prefrontal cortex (PFC). We also investigated gene expression in the arcuate nucleus (ARC), the lateral hypothalamus (LH), and the locus coeruleus (LC). In IMF-treated females at both ages, we observed an improvement in spatial navigation although an impairment in spatial object orientation. IMF-treated females (12 mo) had a reduction and IMF-treated males (12 mo) displayed an improvement in novel object recognition memory. IMF-treated females (18 mo) exhibited anxiolytic-like behavior and increased locomotion. In the DH, IMF-treated males (12 mo) had a greater amount of NE content and IMF-treated males (18 mo) had a reduction. In the ARC, IMF-treated males (12 mo) exhibited an increase in Agrp and Npy and a decrease in Adr1a. In the ARC, IMF-treated males (18 mo) exhibited an increase in Npy and a decrease in Adr1a; females had a trending decrease in Cart. In the LH at 12 months, IMF-treated males had a decrease in Npy5r, Adr1a, and Adr1b; both males and females had a reduction in Npy1r. In the LH, IMF-treated females (18 mo) had a decrease in Hcrt. In the LC at both ages, mice largely exhibited sex effects. Our findings indicate that IMF produces alterations in mood, cognition, DH NE content, and ARC, LH, and LC gene expression depending on sex and age.