Effect of concentrate feeding sequence on equine hindgut fermentation parameters

Abstract

Feeding a diet with a small amount of hay and a high proportion of concentrate given in large meals entails a risk of colic to horses as this can impact the hindgut microbial ecosystem. To counteract this potential negative effect, one feeding strategy is to modify the distribution sequence of concentrate and hay. The purpose of the present study was to assess the impact of feeding the concentrate meal before or with the hay meal on fermentative parameters postprandial variations in caecum and right ventral colon contents and faeces. We focused on the comparison of pH value and volatile fatty acid (VFA) concentrations between the three compartments. Four horses fitted with two cannulas in the caecum and right ventral colon were fed a 100% hay diet (H) for a 3-week period, and then a 40% concentrate-60% hay diet for two consecutive periods of 3 weeks each. Concentrate and hay were offered simultaneously in two equal meals at 0800 and 1700 h (HC1) during one period, or separately in two equal meals at 0800 and 1600 h for the concentrate and at 1000 and 1730 h for hay (HC2) during the second one. During the 2nd week of each diet period (H, HC1, HC2), caecal, right ventral colonic and faecal samples were collected before (0) and at 2, 4, 6 and 8 h after the morning meal. pH values and VFA concentrations were measured. Adding concentrate to the hay was associated with a decrease of pH value in the caecum, right ventral colon and faeces and an increase of faecal VFA concentrations (P<0.01). An impact of the concentrate feeding sequence was observed on caecal pH and faecal propionate concentration (P<0.001) but none on the other parameters investigated. In the caecum and right ventral colon, pH values decreased and VFA concentrations increased within the range of 4 to 8 h after the morning meal. Our data suggested that the variation of faecal pH could be an indicator of those of the caecal and right ventral colonic pH with a delay of 2 h. The present study showed that hay and commercial pelleted could be safely distributed simultaneously, thus making easier every day horse feeding.

A high-starch vs. high-fibre diet: effects on the gut environment of the different intestinal compartments of the horse digestive tract

“…the sternal flexure, pelvic flexure, right dorsal colon and rectum) compared with those fed the HF diet. This finding corroborates those of other studies [ 21 , 26 ] which show that horses fed diets with a high starch content contain high concentrations of total VFAs across all segments of the intestinal tract.…”

Caecal fermentation characteristics of commonly used feed ingredients

“…Greater A:P at 10 h indicates oat hulls were being fermented at this time point. It has been well characterised that fermentation of high‐fibre feedstuffs drives production of acetate, whereas fermentation of high‐starch feedstuffs results in greater propionate and butyrate production 23‐25 . While limited data are available on fermentation of oat β‐glucans by equine caecal microorganisms, in vitro fermentation of oat β‐glucans with human faecal inoculum demonstrated increased production of propionate 26 .…”

Interaction between the sequence of feeding of hay and concentrate, and boiling of barley on feed intake, the activity of hydrolytic enzymes and fermentation in the hindgut of Arabian mares

“…Still, concentrates based on cereals such as barley are indispensable due to the high energy demand of athletic horses. However, diets with high concentrate proportion fed to horses facilitate acidification of the hindgut digesta (Hudson, Cohen, Gibbs, & Thompson, ; Sadet‐Bourgeteau, Philippeau, & Julliand, ) and perturbation of the caecal ecosystem (Hudson et al., ). Concentrate feeding was therefore reported to cause changes in the hindgut microbial ecosystem in horses (Grimm, Philippeau, & Julliand, ; Julliand, De Fombelle, Drogoul, & Jacotot, ; Moore & Dehority, ).…”

“…In particular, the cellulolytic bacteria (Julliand et al., ) and the total population of functional bacteria in the colonic contents of horses (Philippeau, Sadet‐Bourgeteau, Varloud, & Julliand, ) are compromised by concentrates like barley. In the literature, it has been shown that feeding concentrate after or along with the forage portion of the diet could, to some extent, help maintaining an appropriate hindgut physiochemical environment (Jensen, Austbø, & Tauson, ; Sadet‐Bourgeteau et al., ; Zeyner, Geiβler, & Dittrich, ). Another attempt to alleviate potential adverse effects of concentrate on hindgut fermentation could consist of the hydrothermal treatment of cereals to make their starch better accessible to digestion in the small intestine and thus reduce the amount of starch arriving in the hindgut and its adverse influence.…”

“…However, diets with high concentrate proportion fed to horses facilitate acidification of the hindgut digesta (Hudson, Cohen, Gibbs, & Thompson, 2001;Sadet-Bourgeteau, Philippeau, & Julliand, 2016) and perturbation of the caecal ecosystem (Hudson et al, 2001).…”