Evaluation of various barley processing methods on rumen microbial population, histomorphometry, and fermentation characteristics in fattening lamb

Abstract

Barley deserves a top place in the farm for feeding livestock. It is irreplaceable by any other grain in sheep diets for producing capacious rumen microbial yields. The present study was conducted to investigatethe effect of different methods of barley processing on a number of microbes, fermentation parameters, and the rumen tissue characteristics of fattening lambs. For this purpose, 20 fattening male lambs with a mean weight of 25 ± 1.1 kg were tested for 80 daysbasedon a completely randomized design with four treatments (GRB: ground barley, SRB: steam-rolled barley, GEB: germinated barley, SOB: soaked barley) and five replicates. Three lambs from each treatment were slaughtered and sampling was done on the rumen liquid and tissue to determine their pH and volatile fatty acid (VFA), amylolytic bacteria, proteolytic, cellulolytic, heterophilic, and protozoa contents. The findings showed that the number of cellulolytic bacteria in ground barley treatment was lower than that of soaked barley treatment. In addition, there existed fewer heterophilic bacteria in germinated barley groups compared with other treatments. The lactic acid level in the GRB was increased compared to that in SRB and GEB treatments (P < 0.05). The GRB further reduced the thickness of the rumen wall in comparison with SRB. In general, replacing GRB with SOB improved certain thickness of the epithelial tissue and cellulolytic bacteria of the rumen.