Centesimal composition and fatty acids of meat from lambs fed diets containing soybean hulls

The objective of this study was to evaluate the centesimal composition and fatty acids in meat from animals fed diets containing levels of soybean hulls. The experiment was conducted at UESB in Itapetinga-BA, Brazil. Twenty-five confined Santa Inês rams were used. Treatments consisted of different levels of substitution of corn by soybean hulls (0, 25, 50, 75 and 100%) and elephant grass silage as forage. The design was completely randomized. Samples of concentrate and silage were collected to evaluate the fatty acid composition. The experimental period lasted 110 days. After this period, the animals were slaughtered and samples of the longissimus muscle were collected and vacuum-packed for further analysis. The levels of total lipid and protein showed quadratic effect with the increase of soybean hulls in the diet, as the moisture increased linearly with inclusion. There was no effect of treatments on the percentage of ash. The composition of saturated fatty acids (SFA), monounsaturated fatty acids (MUFA), polyunsaturated fatty acids (PUFA), PUFA/SFA and omega 6 (n-6) did not change, but increases in n-3 and reduction in the n-6:n-3 ratio were observed when the the amount of soybean hulls in the diet increased. The content of fatty acid conjugated linoleic acid (CLA) ranged from 3.0 to 4.0 g/kg at levels of substitution. The inclusion of soybean hulls in the diet increased CLA, the n-3 and decreased the n-6:n-3 ratio.