Abstract
(Received 11 September 2009; revised version 2 February 2011; 12 March 2011)ABSTRACTThis study evaluates the effects of three diets: a control (CON), containing sodium monensin (MON) and containing propolis extract (PRO). The performance of 33 feedlot-finished bulls, 11 for each diet, and carcass characteristics were examined. The 27 months old bulls, with initial liveweight 400±2.33 kg, were kept in a feedlot for 84 days, till 484±6.76 kg at slaughter. The roughage and concentrate ratio of the diets was 52:48 on DM basis. Maize silage was used as roughage and maize, soyabean meal, urea, mineral salt and limestone were used as concentrate. The average final weight (501 kg), hot carcass weight (275 kg) and average daily gain (1.17 kg) were higher (P<0.05) for bulls fed with PRO than for those on the CON (472, 259 and 0.87 kg, respectively), or MON (480, 259 and 0.94 kg, respectively) diets. Dry matter conversion was better (P<0.05) for bulls fed with PRO (8.04) than those on the CON (10.9) or MON (9.72) diets. Carcass characteristics such as conformation, carcass length, leg length, cushion thickness,
Highlights
Meat plays an important role in human diet, providing high quality protein (Rotta et al, 2009b), essential fatty acids (Maggioni et al, 2009; Rotta et al, 2009a,b), minerals and B-complex vitamins
The presence of saturated fatty acids in beef is related to the biohydrogenation process that occurs in the rumen
Coloration was evaluated according to a point scale (Müller, 1980) 30 min after a transversal section was made on the Longissimus muscle between the 12th and 13th ribs, hydrogen potential was determinate with a pH meter; the electrode was inserted in the muscle between the 12th and 13th ribs after the carcass was chilled for 24 h
Summary
Meat plays an important role in human diet, providing high quality protein (Rotta et al, 2009b), essential fatty acids (Maggioni et al, 2009; Rotta et al, 2009a,b), minerals and B-complex vitamins. Feed additives like antibiotics or growth-promoting agents have become an integral part of ruminant production. Monensin selectively inhibits the growth of gram-positive bacteria; this inhibition reduces lactic acid production and methanogenesis in the rumen, increases the molar proportion of propionate and N retention (Goodrich et al, 1984). Köhler et al (2000) reported that certain anti-bacterial agents used as growth promoters might increase the horizontal transfer of virulence genes between bacteria, this effect was not observed from monensin in vitro. Because propolis can inhibit the growth of gram positive bacteria, in might be a useful additive for modifying microbial fermentation in the rumen (Ozturk et al, 2010). We found no reports of studies that examined the effects of propolis extract on the quality of cattle meat. This work was carried out to study the effects of sodium monensin or propolis extract on the performance and carcass characteristics of feedlot-finished Nellore bulls
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