Investigations on Preileal Digestion of Starch from Grain, Potato and Manioc in Horses

Abstract

Summary In this study preileal starch digestibility of starchy feeds (oats, corn, barley, potatoes, manioc) was determined in seven jejunofistulated horses. The grains were fed whole (oats, corn), rolled (oats, barley), crushed, ground and expanded (corn); the potatoes were fresh, the manioc rolled. Ground corn was also fed in combination with amylase. The feeds were fed partly isolated or in combination with alfalfa meal or hay (Table 1). At least four horses with a cannula in the terminal jejunum were used for each diet. Two meals per day were offered at 12 h intervals. The starch intake was mostly about 2 g/kg bw/meal, except one period with oats (3.9 g starch/kg bw) and with expanded corn (1.4 g/kg bw). Jejunal chyme was postprandially collected 11 times (from 1st to the 11th h after the morning meal for 15 min). Starch was determined polarimetrically. The preileal digestibility of starch was calculated by the marker method (chromic oxide 0.25% DM) and by estimating the total jejunoileal chyme flow during 12 h postprandially extrapolating the sample volume from the 15 min sampling periods. The results of both methods agreed quite well. Preileal digestibility of oat starch (80–90%) was (independent of doses or preparation or of the combination with hay, Table 4) significantly higher than that of whole or crushed corn (30%) or barley (26%). Grinding of corn significantly increased preileal digestibility to 51%, expanding to 90%. The addition of amylase improved digestion of ground corn by 10% (absolute). The preileal digestibility of potato or manioc was less than 10%. Individual factors in the horse (chewing intensity, amylase activity) had also considerable influence on preileal starch digestibility.

The Effect of Steaming and Soaking on the Respirable Particle, Bacteria, Mould, and Nutrient Content in Hay for Horses

“…However, the nutrient, and in particular energy demands of performance horses have necessitated the incorporation of large amounts of energy-dense cereal grains in the diets of these animals, which are high in starch and low in fibre. It is well known that the small intestine of the horse has a limited capacity for starch digestion (Kienzle et al, 1994;Meyer et al, 1995) and thus when high levels of starch are fed in a single meal, undigested starch enters the hindgut. Excess starch entering the hind-gut favours the proliferation of Gram positive lactic acid producing bacteria in the hindgut of the horse at the expense of the Gram negative fibre-degrading bacterial population.…”

A contribution to the praeileal absorption of vitamine C in the horse

“…Die präilede Verdaulichkeit wurde aufgrund der Askorbinsäuregehalte im Chymus und des Chymusflusses innerhalb von 12 Std, ppr. berechnel (Meyer et al 1995),…”

“…Studien über die Höhe der Absorption verschiedener Vitamin-C-Produkte im Magen/Dunndarm, wo nach Er-fahrungen bei anderen Spezies die Absorption stattfindet (Hornig 1975), liegen beim Pferd bisher nicht vor. lm Rahmen fruherer Arbeiten uber die präileale Verdauung von Stärke (Meyer et al 1995) konnten in einem Testversuch erste Hinweise über die Höhe der Vitamin-C-Absorption bei Pferden gewonnen werden.…”

Mouldy feed: A possible explanation for the excretion of anabolic‐androgenic steroids in horses

“…[30] The focus is on the hindgut as complex fermentation reactions only take place in the caecum and colon, the enzymatic activity and digestion measured in the foregut of horses is fairly low. [53] The α-amylase activity was estimated between 10 and 50 U/g [54] compared to 3500 U/g for other species such as humans and pigs. [54] Upon addition of (mouldy) corn and/or phytosterols (50% β-sitosterol) to the in vitro digestion, AED could be detected throughout the entire digestion period.…”

“…[53] The α-amylase activity was estimated between 10 and 50 U/g [54] compared to 3500 U/g for other species such as humans and pigs. [54] Upon addition of (mouldy) corn and/or phytosterols (50% β-sitosterol) to the in vitro digestion, AED could be detected throughout the entire digestion period. The highest concentrations of AED were obtained for the combination of mouldy feed with added phytosterols.…”