Effects of Dietary Protein and Fat Levels on Growth Performance and Meat Quality in Finishing Pigs while Maintaining Sufficient Lysine

We conducted a study to evaluate the effects of dietary protein and fat levels, while maintaining appropriate levels of lysine and protein for nutrition, on growth performance, carcass characteristics, and meat quality in finishing pigs. Crossbred pigs (n = 32) were assigned to a 2 × 2 factorial arrangement of four dietary treatments: two protein levels (20% vs. 23%) and two fat levels (approximately, 2.5% vs. 6.2%). The examined diets were filled lysine content for finishing pigs. Each diet had similar digestible energy content. Average daily gain was not affected by dietary protein levels. No significant differences were observed in carcass characteristics. Intramuscular fat content in the longissimus dorsi muscle increased with higher dietary protein and the moisture and shear force were decreased. Most measurements of meat quality except for fat quality were not significantly affected by dietary fat. Our study indicates that intramuscular fat and marbling increase with increased dietary protein (assuming the diet contains sufficient lysine according to the feed standard), without having an adverse effect on the growth performance of finishing pigs and that intramuscular fat was affected little by dietary fat level.