Glycaemic and insulinaemic responses of adult healthy warm‐blooded mares following feeding with Jerusalem artichoke meal
Common pre‐biotics used in horse nutrition are often fructans, which consist of several fructose units and one terminal glucose unit (Roberfroid, 2007). Depending on the chemical composition, fructans are classified as inulin‐type fructans (ITFs, common in Compositae) or phlein‐type fructans (common in Poales; Glatter et al., 2016a). Depending on the dose, both types of fructans can have harmful or beneficial effects on a horse's health. With very high intake, particularly by not or only insufficiently adapted horses, phlein‐type fructans (Longland and Byrd, 2006) as well as inulin‐type fructans (Van Eps and Pollit, 2006, 2009) can trigger laminitis. Laminitis is often associated with endocrine insulin dysregulation, which leads secondarily to permanent stimulation and subsequent downregulation of the insulin receptors (De Laat et al., 2016). The development of insulin resistance (IR) related to hyperinsulinemia is often linked to clinical signs of laminitis (Kronfeld et al., 2005; Asplin et al., 2007; Bailey et al., 2007; De Laat et al., 2010). Ponies predisposed to laminitis showed a 5.5‐fold higher serum insulin concentration after feeding of 3 g inulin/kg bwt per day (over 48 h) in comparison with control ponies (Bailey et al., 2007). The respective differences in serum insulin between laminitis prone and normal ponies were however of minor importance following only 1 g inulin/kg bwt per day over the course of 3 days (Borer et al., 2012). Dietary supplementation with 45 g of short‐chain fructo‐oligosaccharides (scFOS) during 6 weeks significantly increased insulin sensitivity and reduced acute insulin response to glucose in comparison with maltodextrin in obese Arabian geldings (body condition score [BCS] 8/9) without affecting body weight and BCS, but did not alter glucose effectiveness (Respondek et al., 2011). In this study, resting serum insulin concentration was reduced by scFOS but not maltodextrin supplementation. The aim of this study was to investigate the effect of a natural pre‐biotic (Jerusalem artichoke, Helianthus tuberosus) on the glycaemic and insulinaemic responses in adult healthy, non‐obese, warm‐blooded mares with no known history of laminitis. We hypothesized that even clinically normal, non‐obese horses might benefit from daily pre‐biotic doses of FOS and inulin from Jerusalem artichoke meal (JAM) by improved insulin sensitivity and thus postprandial (PP) glucose clearance following a hay–concentrate meal.