Effect of Biological Treatment of Barley Straw with Baker's Yeast (Saccharomyces Cerevisiae) on Some Productive Performance of Growing Lambs

Abstract

This study was conducted at the farm of Ruminants Research Station, Office of Agricultural Research, Ministry of Agriculture, Abu Ghraib – Baghdad. The experiment continued for 56 days, in addition to 14 days as preliminary period from 11/10/2015 until 06/12/2016 to study the effect of treating barley straw with baker’s yeast (Saccharomyces cerevisiae) on some productive performance of growing lambs. Ten Awassi lambs used in this experiment with average initial weight of 38±0.50 kg and age 8-9 months. Lambs divided randomly into two equal groups and kept in separate individual pens. Lambs fed individually on a unified concentrate diet (2.5% of body weight), while, roughages offered ad libitum. Each group fed on roughages (barley straw), as follows: 1. The first group fed untreated barley straw plus concentrate mixture and operated as control 2. The second group fed barley straw treated with baker’s yeast (Saccharomyces cerevisiae) at rate 0.5% (5 kg / tones). Animals weighed every two weeks before morning feeding. The digestibility experiment performed in the seventh week. Rumen liquor collected at fifth week of the experiment at three times (before feeding, after three and six hours from feeding). Results showed different effects among treatments. The yeast not significantly affected the feed intake, average daily gain (15 – 28 d), in vivo digestibility, and rumen fermentation (pH and NH3-N). Moreover, there was significant decrease (P <0.05) in daily weight gain during 29 42 d with baker’s yeast compared with control (107.14 and 160.71g/d, respectively), while a significant increase (P <0.05) found in daily weight gain in the (1 – 14 d and 43 – 56 d) with baker’s yeast (103.57 and 178.57 g/d, respectively) compared with control (48.33 and 142.86 g/d, respectively). We conclude that treatment with baker’s yeast not improved feed conversion ratio, feed intake, intake of different nutrients, weight gains, digestibility and rumen fermentation (pH and NH3-N concentration). INTRODUCTION Raising sheep in Iraq are suffering a lot of obstacles and problems. One of the most important problems is feeding where down spaces pastures as well as low areas allocated for cultivation of green fodder, are not consistent with needs and requirements of animals. (AlSaady, 2009). So, many researchers resort to use low quality forages that characterize with low nutritive value and contain high percentage of lignin to compensate this shortage (Mahesh and Mohini, 2013). Many treatments were conducted to improve the nutritional value of low quality feeds including physical, chemical treatments (Al-Zubaidi, 2006, Hassan, 2004) and biological treatments (Hassan et al., 2007), which helps to break link between lignin and cellulose and increase cellulose for ease using by ruminant animals (Mahesh and Mohini, 2013). Fungi used in biological treatments where research still going to know the best and qualified fungus to improve the nutritional value of forage and of these fungus the baker’s yeast (Saccharomyces cerevisiae) tested in this study. It is of the kinds used to break link between lignin and cellulose (Nsereko et al., 2002). The baker’s yeast is a rich source of protein, vitamin B composite, minerals and enzymes as well as important elements for immunity (Milewski and Sobiech, 2009). It works to improve the performance of ruminants by affecting rumen microorganisms (Inal et al., 2010). Effect of biological Treatment of Barley Straw with Baker’s Yeast (Saccharomyces cerevisiae) on some productive performance of growing lambs 37 Wafaa H. Al-Samaraee, et al., 2016 Therefore, the purpose of this study was to know the effect of feeding barley straw treated with baker’s yeast (Saccharomyces cerevisiae) on the performance of Awassi Lambs. MATERIALS AND METHODS This study was conducted in the farm of Ruminants Research Station, Office of Agricultural Research, Ministry of Agriculture, Abu Ghraib – Baghdad. The experiment continued for 56 days in addition to 14 days as preliminary period, from 11/10/2015 to 06/12/2015. The purpose of the study was to investigate the effect of treating barley straw with baker’s yeast (Saccharomyces cerevisiae) on some productive characteristics of growing lambs (feed intake, daily gain and feed conversion ratio) digestibility, and rumen characteristics (ruminal pH and ammonia–N concentration). Table (1): The chemical composition of barley straw (T1), treated barley straw (T2) and concentrate diet (% of dry matter) Concentrate T2 T1