Effect of Monensin and Live Yeast Supplementation on Growth Performance, Nutrient Digestibility, Carcass Characteristics and Ruminal Fermentation Parameters in Lambs Fed Steam-flaked Corn-based Diets

J Ding,L P Ren,Z M Zhou,Q X Meng

doi:10.5713/ajas.2008.70353

Abstract

In performance, digestibility and slaughter trials, a total of forty five male weaned lambs were used to examine the effects of monensin and live yeast supplementations on growth performance, nutrient digestibility, carcass characteristics and ruminal fermentation parameters when the lambs were fed steam-flaked corn-based diets. Animals were allotted to one of three treatment diets in a completely randomized design. The three treatment diets were: (1) basal diet (CON) with steam-flaked corn as a sole grain source, (2) basal diet supplemented with monensin (MO), and (3) basal diet supplemented with live yeast (LY). Total average daily intake (ADI) was unaffected by MO and LY supplementations. LY supplementation increased (p<0.05) average daily gain (ADG) by 13.1% compared with the CON diet. Both MO and LY supplementations resulted in a significant improvement (p<0.05) of feed efficiency over the CON diet (4.47, 4.68 vs. 5.05). Hemicellulose digestibility was higher (p<0.05) for lambs in the LY supplementation group (62.4%) as compared with the CON group (55.7%), but no differences were observed in digestibilities of dry matter (DM), organic matter (OM), crude protein (CP), neutral detergent fiber (NDF) and acid detergent fiber (ADF). All carcass traits were not influenced by dietary supplementations. Ruminal pH in lambs fed the LY supplemental diet was more stable than that with the CON diet (6.57 vs. 6.17). Neither MO nor LY supplementation influenced the concentration of ruminal ammonia-N and total volatile fatty acid (VFA), and molar percentages of individual VFA. Plasma urea-N concentration was decreased (p<0.05) by MO and LY supplementations, while plasma β-hydroxybutyrate (BHBA), glucose and other blood parameters were unaffected. In conclusion, while both MO and LY supplementations had a positive impact on feed efficiency and LY supplementation stabilized ruminal pH and improved fiber utilization, none of the supplements had the capacity to significantly enhance the carcass characteristics.

Highlights

Steam-flaked corn is a widely used grain for ruminants in many countries, because steam flaking is known to effectively improve the feeding value of grains, principally through increasing the rate and extent of grain starch digestion in the rumen and the intestines by increasing the degree of starch gelatinization (Zinn et al, 1995)
The modes of action of monensin rely on selective growth inhibition of gram-positive organisms (Van Nevel and Demeyer, 1988), reducing lactic acid production (Dennis et al, 1981) and methanogenesis in the rumen (Goodrich et al, 1984) and increasing molar proportion of propionate (Goodrich et al, 1984) and N retention (Adams et al, 1981)
The objective of the present study was to compare the effects of monensin and live yeast supplementations to the steam-flaked corn-based diets fed to the weaned lambs on their growth performance, nutrient digestibility, carcass characteristics and ruminal fermentation parameters to provide some evidence in support that active yeast have the potential to replace in-fed antibiotics

Summary

Introduction

Steam-flaked corn is a widely used grain for ruminants in many countries, because steam flaking is known to effectively improve the feeding value of grains, principally through increasing the rate and extent of grain starch digestion in the rumen and the intestines by increasing the degree of starch gelatinization (Zinn et al, 1995). The rapid ruminal fermentation rate of grain starch may yield a potential risk to rumen microbial ecosystem due to the accumulation of organic acids within the rumen (Reinhardt et al, 1997). The modes of action of monensin rely on selective growth inhibition of gram-positive organisms (Van Nevel and Demeyer, 1988), reducing lactic acid production (Dennis et al, 1981) and methanogenesis in the rumen (Goodrich et al, 1984) and increasing molar proportion of propionate (Goodrich et al, 1984) and N retention (Adams et al, 1981). The positive production responses of livestock to dietary monensin supplementation have been welldocumented, e.g. improvement of feed conversion, in high-grain diets (Boucqué et al, 1982).

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