Effect of different sources of grain on nutrient digestibility in horse using two internal markers

Twelve Turkmen horses with an average weight of 425 ± 4 kg and age of 6 ±1.8 years were used in the experiment. In all rations, the ratio of concentrate to forage was 65:35. Corn and oats, barley and wheat and barley with oats were used as a source of starch in 1, 2 and 3 ration respectively. Lignin and acid insoluble ash (AIA) were used as internal markers to determine the nutrient digestibility. Using lignin or AIA methods, the digestibility of dry matter, organic matter, ether extract and digestible energy were significantly increased in treatment 1 (P<0.05). Digestion coefficients of ash-free neutral detergent fibre, ash-free acid detergent fibre, cellulose and hemicellulose were increased for treatments 1 and 3 (P<0.05). The digestion coefficients obtained by using both markers there was not significantly different (P >0.05) except in the case of ADFom and cellulose in diet 1 and ADFom, hemicellulose and cellulose in diet 2. However, the recovery rate of AIA and lignin were 106% and 91% respectively, the recovery rates of these markers are highly correlated with the total faecal collection method. In general, the inclusion of corn and oats in the ration has led to improve the nutrients digestibility compared to those without corn and oats.