Fatty Acid Profile of Intramuscular Fat in the Longissimus Lumborum and Semimembranosus Muscles of Bulls Fed Diets Based on Virginia Fanpetals, Grass and Maize Silages

The aim of this study was to determine the effect of Virginia fanpetals (Sida hermaphrodita) silage on the fatty acid profile and the content of selected nutrients and vitamins in the Longissimus lumborum (LL) and Semimembranosus (SM) muscles of young bulls. Forty Polish Holstein-Friesian bulls aged 16 months were assigned to four dietary treatments (n=10) and were fed different types of silage during a 7-month fattening period. The proportion (g/kg dry matter) of silage in the diets was as follows: (1) grass silage (GS) (600); (2) Virginia fanpetals silage (VFS) (600); (3) VFS (300) and GS (300); and (4) VFS (300) and maize silage (MS) (300). Silage was supplemented with concentrate at 400 g/kg DM in each diet. The animals were slaughtered at the end of the fattening period. The intramuscular fat (IMF) of bulls fed GS had the highest (P<0.05) concentrations of n-3 polyunsaturated fatty acids (PUFAs) and linolenic acid (LNA), whereas the IMF of bulls receiving GS and VFS was characterized by the highest proportion of MUFAs, mostly oleic acid (C18:1 cis 9). In comparison with the LL muscle, the SM muscle contained less IMF (by 40%) with a more nutritionally desirable profile. The SM muscle was characterized by a more desirable mineral composition and a higher concentration of α-tocopherol.