PHYSICAL AND CHEMICAL AND FATTY ACID PROFILE IN THE STEERS BEEF WITH DIFFERENT GENETIC PREDOMINANCE FED WITH DIETS CONTAINING SUBSTITUTIONS LEVELS OF CORN BY PEARL MILLET

Abstract Text: This study aimed to evaluate the steers crossbred meat fatty acid profile with European (E) or Zebu (Z) genotypic predominance fed with high concentrated diets (80%) containing levels of ground millet grain in replacement of ground corn grain (0, 33, 66 and 100%). Twenty-four steers of each genetic predominance were feedlot during 96 days and slaughtered at 24 months of age. The experimental design was completely randomized design with treatments in a 4x2 factorial arrangement using six replicates. The initial pH (6.68) and final carcass pH values (5.9), the final carcass temperature (9.72ºC), the fluid loss during thawing (9.7%) and cooking (26.6%), color (3.7 points), texture (3.1 points), marbling (4.5 points), the shear strength of the muscle fibers (8.1 kgf) and moisture (72.9% ), crude protein (23.0%) and ether extract content (1.5%) of the meat were not affected by the substitution of corn grain by millet grain (P>0.05). Meat characteristics were not influenced by genetic predominance, except the marbling, which was higher (4.99 vs. 3.95 points) in European animals. The final pH was correlated with thawing liquid loss (r = -0.36) and meat color (r = -0.62). The replacement of corn grain by millet grain in diet did not affect the steers meat quality (P>0.05). Increasing the proportion of millet in the diet it linearly increased the arachidic (C20:0), heneicosanoic (C21:0), α linolenic (C18:3 n-3) and di-homo γ linolenic (C20:3 n-6) fatty acids. European bulls meat showed less content of myristic (C14:0), heneicosanoic (C21:0) and γ linolenic (C18:3 n-6) fatty acids. The total concentration of saturated (45.2%), monounsaturated (41.2%) and polyunsaturated (8.7%) fatty acids and monounsaturated/saturated (1.09) and polyunsaturated/saturated (0.18) relationship were not affected by the factors studied. Zebu cattle fed high concentrate produce meat with higher levels of hypercholesterolemic fatty acids that European cattle. The millet grain precentage increase in the diet of European and zebu crossbred steers improves the ratio between n-6/n-3 fatty acids (0%= 13.90,  33%=13.79, 66%=11.67, 100%=10.58) (P=0.042). These results indicate that the millet grain used in a complementary way for other strategies, such as providing protected polyunsaturated fatty acids (PUFA) ruminal fermentation, may allow getting a closer relationships ω6/ω3 to the recommended.

Keywords: intramuscular fat, meat tenderness, nutition