A Novel Automated System Yields Reproducible Temporal Feeding Patterns in Laboratory Rodents. Issue 9 (9th July 2019)

• Record Type: Journal Article
• Authors: Tilston, Thomas W; Brown, Richard D; Wateridge, Matthew J; Arms-Williams, Bradley; Walker, Jamie J; Sun, Yuxiang; Wells, Timothy
• Is Part Of: Journal of nutrition. Volume 149:Issue 9(2019)
• Page Start: 1674
• Page End: 1684
• Publication Date: 2019-07-09
• Subjects: feeding patterns -- meal-feeding -- grazing -- meal microstructure -- automated feeding -- automated blood sampling -- corticosterone profiles -- ghrelin; Nutrition -- Periodicals; Diet -- Periodicals; 613.205
• DOI: 10.1093/jn/nxz116
• Languages: English
• ISSNs: 0022-3166

Abstract

ABSTRACT: Background: The impact of temporal feeding patterns remains a major unanswered question in nutritional science. Progress has been hampered by the absence of a reliable method to impose temporal feeding in laboratory rodents, without the confounding influence of food-hoarding behavior. Objective: The aim of this study was to develop and validate a reliable method for supplying crushed diets to laboratory rodents in consistent, relevant feeding patterns for prolonged periods. Methods: We programmed our experimental feeding station to deliver a standard diet [StD; Atwater Fuel Energy (AFE) 13.9% fat] or high-fat diet (HFD; AFE 45% fat) during nocturnal grazing [providing 1/24th of the total daily food intake (tdF/I) of ad libitum–fed controls every 30 min] and meal-fed (3 × 1-h periods of ad libitum feeding) patterns in male rats (Sprague-Dawley: 4 wk old, 72–119 g) and mice [C57/Bl6J wild-type (WT): 6 mo old, 29–37 g], and ghrelin -null littermates (Ghr −/− ; 27–34 g). Results: Grazing yielded accurate, consistent feeding events in rats, with an approximately linear rise in nocturnal cumulative food intake [tdF/I (StD): 97.4 ± 1.5% accurate compared with manual measurement; R 2 = 0.86; tdF/I (HFD): 99.0 ± 1.4% accurate; R 2 = 0.86]. Meal-feeding produced 3 nocturnal meals of equal size and duration in StD-fed rats (tdF/I: 97.4 ± 0.9% accurate; R 2 = 0.90), whereas the second meal size increased progressively in HFD-fed rats (44% higher on day 35 than on day 14; P < 0.01). Importantly, cumulative food intake in grazing and meal-fed rats was identical. Similar results were obtained in WT mice except that less restricted grazing induced hyperphagia (compared with meal-fed WT mice; P < 0.05 from day 1). This difference was abolished in Ghr −/− mice, with meal initiation delayed and meal duration enhanced. Neither pattern elevated corticosterone secretion in rats, but meal-feeding aligned ultradian pulses. Conclusions: We have established a consistent, measurable, researcher-defined, stress-free method for imposing temporal feeding patterns in rats and mice. This approach will facilitate progress in understanding the physiologic impact of feeding patterns.