Nutritional approaches to increase intramuscular fat in pigs

Studies were conducted to evaluate the effects of nutrition on intramuscular fat (IMF) and pork quality. The first study evaluate if intramuscular fat content can be increased in pigs by feeding vitamin A deficient diets. This study demonstrated that there was no effect of feeding vitamin A (P > 0.05) on chemically determined IMF content (3.15 vs. 2.94%, SEM = 0.164; for adequate and deficient diet, respectively). A second study compared the effects of dietary inclusion of high oleic acid sunflower oil or soybean oil on growth and meat quality. Meat quality and carcass characteristics were not (P > 0.05) modified by oil type, but fat sources with high oleic fatty acid content can be used in the finishing diet with no detrimental fat quality (Iodine value ≤ 70). Another study was carried out to define the appropriate degree of deficiency of dietary protein and/or amino acids and the optimum time to feed deficient diets in order to obtain target increases in intramuscular fat content. There was a feeding time by diet (P < 0.05) interaction for longissimus intramuscular fat, the diet in which only the lysine was reduced by 44% of the control for either 42 or 63 d produced the largest increase in intramuscular fat. The results from this experiment suggest that dietary protein and lysine level influence the IMF content of pork. The last study was carried out to establish the effect of dietary protein, lysine levels, and source of protein on intramuscular fat content and pork quality. These results confirm that dietary protein and lysine level influence the IMF content of pork, with a high crude protein and a low true digestible lysine in the diet resulted in the higher increments.