The Effect of Feeding Horses a High Fiber Diet With or Without Exogenous Fibrolytic Enzymes Supplementation on Nutrient Digestion, Blood Chemistry, Fecal Coliform Count, and In Vitro Fecal Fermentation

Abstract

a b s t r a c tSixteen Quarter Horse mares (450 to 500-kg body weight) were used in a complete randomized design to determine the effects of feeding a high fiber diet with or without exogenous fibrolytic enzymes on nutrient digestion, blood chemistry, fecal coliform count, and in vitro fecal fermentation. The treatments comprised feeding the horses (1) a basal diet without enzyme addition (control); (2) control diet plus cellulase at 10 mL/mare/ d (CELL); (3) control diet plus xylanase at 10 mL/mare/d (XYL); or (4) control diet plus a mixture of 5 mL cellulase and 5 mL xylanase/mare/d (CX). The basal concentrate diet consisted of a mixture of 50% commercial concentrate and 50% wheat bran fed at 4 kg/ horse, offered twice daily at 04:00 and 16:00 hours, and oat straw offered ad libitum at 05:00 and 17:00 hours. The enzyme allocation for each day was mixed with 1 kg of concentrate diet at 04:00 hours, and the experiment lasted for 15 days comprising 10 days of adaptation and 5 days for sample collection. The in vitro cecal fermentation with addition of 2 mL/g dry matter (DM) of each enzyme (CELL, XYL, and CX) to a basal diet of oat straw and concentrates mixture (1:1 DM) as a substrate was carried out. The mares fed enzyme-supplemented diets had greater (P < .01) oat straw and total nutrients intakes compared with the control diet. Feeding enzyme-supplemented diets increased total nutrients digestibility (P < .05) and blood total protein (P ¼ .0277) compared with the control. Feeding XYL-supplemented diet increased blood alanine transaminase and aspartate aminotransferase concentrations (P < .05) compared with control treatment. Lower fecal coliform count was obtained (P ¼ .0114) with mares fed CX diet compared with control mares. The XYL and CX treatments had decreased asymptotic gas production (GP) (P ¼ .0173) with lower rate of GP (P ¼ .0412) compared with CELL treatment. CELL and XYL treatments had decreased (P ¼ .0394) lag times compared with control and CX treatments. At 24 hours of incubation, CELL and XYL treatments decreased methane production (P ¼ .0131), whereas CX treatment increased its production at 48 hours (P ¼ .0202) compared with control treatment. No effect was observed (P > .05) with enzymes addition on carbon dioxide production at different hours of incubation compared with control treatment. Higher in vitro DM degradability values (P ¼ .0092) were obtained with the enzyme

Effectiveness of xylanase and Saccharomyces cerevisiae as feed additives on gas emissions from agricultural calf farms

“…In contrast, Kholif et al (2016) reported that the addition of enzymes at certain doses reduced CH 4 production in equine diets. Salem et al (2015b) observed the same results in horses fed diet supplemented with exogenous enzymes. In the present study, addition of enzymes at all doses decreased CH 4 production.…”

In Vitro Assessment of Fecal Inocula From Horses Fed on High-Fiber Diets With Fibrolytic Enzymes Addition on Gas, Methane, and Carbon Dioxide Productions as Indicators of Hindgut Activity

“…Therefore, there is a need to develop feeding strategies that meet the energy requirements of the horse fed high-fiber diets and maintain gut health and integrity [6]. For an effective utilization of fibrous feeds, exogenous fibrolytic enzymes have been used to improve carbohydrate and cell wall degradation in ruminants [7,8] and in equines [9].…”

“…In ruminants, supplementing diets with fibrolytic enzymes has been shown to improve feed utilization and animal performance [10,11]. Supplementing the diet of horses with exogenous fibrolytic enzymes has gained substantial interest in recent years [9,12]. Because the large intestine in the horses is a fermentation system similar to the rumen [13], improvements in feed utilization and animal performance should be expected with horses with fibrolytic enzymes supplementation.…”

“…However, the potential of exogenous enzymes to enhance the digestion of fibers in the hindgut of the equine is inconclusive. Salem et al [9] observed in vivo improved neutral detergent fiber (NDF) and acid detergent fiber (ADF) digestion of oat straw when mares were fed fibrous diet supplemented with fibrolytic enzymes. In contrast, Murray et al [12] reported a significant reduction in in vivo digestibility of the fibrous fractions of enzyme-treated diets.…”

Influence of Aguamiel ( Agave atrovirens ) as a Natural Feed Additive on Cecal Fermentation Kinetics of Some Forage Species in Horse Feeding

“…Feed additives, like exogenous enzymes, have been used to improve degradation of carbohydrate and cell wall in ruminant animals [7,8] and in equines [9], but little or nothing is known about the use of aguamiel, a natural feed additive, in horse nutrition. In recent years, supplementation of horse diet with feed additives has aroused the interest of livestock researchers [1,2,9,10]. Aguamiel (honey water) is the sap obtained from one of the agave species (Agave atrovirens) grown in the semidesert areas of Mexico and used by Mexicans as a natural fortifying beverage.…”