Effects of the dietary energy source on meat quality and eating quality attributes and fatty acid profile of Simmental bulls

Seventy-two Simmental bulls, weighing at the beginning of the experiment 408±24 kg, were fed fibrous or starch diets to a final weight of 622±34 kg. The animals were divided into three groups fed with the following: grass silage plus sugar beet pulp (GSS, n = 18) as a predominantly fibrous diet, maize silage plus wheat (MSW, n = 27) and maize silage plus corn (MSC, n = 27) as predominantly starch diets with different ruminal degradabilities of the starch. The dietary source of energy had no significant effects on the following meat characteristics: pH, colour, weight losses at ageing and grilling, grilling time and shear force values. These meat quality traits were also not affected by the dietary source of starch, rapid degradable (MSW) or slow degradable (MSC). In loin muscle steaks, sensory evaluation revealed no significant differences in tenderness and juiciness among the three groups. The steaks of the grass silage fed group (GSS) were rated lower for flavour than the steaks from the maize silage fed groups (MSW, MSC), with the difference between GSS and MSC being significant. The MSC group also had the highest intramuscular fat content with 1.96% (P < 0.05). Feeding the GSS diet significantly increased the saturated fatty acids in the in- tramuscular and kidney fat compared to the MSW and MSC diets. Also, most polyunsaturated fatty acids especially n-3 fatty acids were increased by feeding the GSS diet. The MSC diet significantly reduced the PUFA in the intramuscular and kidney fat compared to the GSS diet. MUFA content was significantly higher when feeding starchy diets.