Resumen:
This experimentwas conducted to evaluate in vitro effects of equine fecal inocula fermentative capacity on 9 fibrous forages in the presence of Saccharomyces cerevisiae. The fibrous feeds were corn stover (Zeamays), oat straw(Avena sativa), sugarcane bagasseandleaves (Saccharum officinarum), llanero grass leaves (Andropogon gayanus), Taiwan grass leaves (Pennisetum purpureum), sorghum straw (Sorghum vulgare), and steria grass leaves (Cynodon plectostachyus). Fibrous feed samples were incubated with several doses of S. cerevisiae; 0 (control), 1.25 (low), 2.5 (medium) and 5 (high) mg/g dry matter (DM) of a commercial yeast product containing 1 1010/g. Fecal inoculumwas collected from4 adult horseswere fed onanamount of commercial concentrate and oat hay ad libitum. Gas production (GP)was recorded at 2, 4, 6, 8, 10, 12, 24, and 48 hours post inoculation. An interaction occurred between feeds and yeast dose for fecalpH(P<.01), asymptoticGP (b, ml/gDM); rate ofGP (c, /hr); initial delay beforeGP began (L, hours),GPat 4 hours and48 hours (P<.01), andGPat 8 hours (P<.01) andat 24 hours (P<.01). Differences in fecal fermentation capacity between the tropical and template grass (P < .05) occurred for fecal pH, c, and GP during first 12 hours, whereas differences occurred (P< .05) between the agriculture byproducts and the grasses for fecal pH, b, and GP from 8 to 48 hours. Fermentation capacity between straws versus not straws (P <.05) differed for fecal pH, b, and GP after 12 hours between straws versus not straws. Addition of S. cerevisiae to Z. mays stover reduced (P <.01) fecal pH and the c fraction with a higher (P <.01) b fraction versus the other feeds. From4 to 24 hours, S. officinarumbagasse improvedGP tothe highest values versus S. officinarum leaves. After 24 hours, Z. mays stover had the highest GP, whereas C. plectostachyus leaves had the lowest. There were no differences among the yeast doses for all measured parameters with the exception of L values (linear effect; P <.01). The Z. mays stover hadthe highestnutritive comparedtothe otherfibrous feeds.However, additionof S. cerevisiae at 2.5 to 5.0 g/kg DM improved fecal fermentation capacity of low-quality forages
Descripción:
There is increasing interest in feeding fiber-based feeds as an alternative to high-starch cereal grains to horses as a means of meeting the energy demands and reduce various pathologies, such as gastric ulceration, hind-gut acidosis, laminitis, and colic [2,3], associated with feeding high levels of cereal grains. Depending on the forage type and time of harvest, forages of moderate to high nutritive value may meet the energy and crude protein (CP) requirements of horses [4]. Horses naturally use forage as a primary component of their diet, and forage is a basic necessity for normal function of the equine digestive system. High forage rations are desirable because they contain low levels of starch and sugar. Feeding a minimum 1% of body weight as fiber is very important to minimize the incidence of hindgut acidosis [5], colic [6], gastric ulcers [7], and stereotypical behaviors [8]. In tropical areas such as Mexico, forages used as feeds are generally low in digestibility and low in true protein [9]. Therefore, there is a need to develop feeding strategies which meet the requirements of performance horses while maintaining gut health and integrity.