Nutritional strategies affect carcass and pork quality but have no effect on intramuscular fat content of pork

Fifty crossbred (Large White × Landrace × Duroc) female finisher pigs were used to determine the effect of nutritional strategies on intramuscular fat content. The dietary treatments were (A) Control: commercial grower and finisher diet, (Day 68–166), (B) –15% P:E and –vitamin A: a 15% reduced protein:energy grower diet with no supplemental vitamin A (Day 68–110), followed by a commercial finisher diet (Day 111–166), (C) sugar: a grower diet supplemented with 10% sugar (Day 68–110), followed by a commercial finisher diet (Day 111–166), (D) zinc: a grower diet supplemented with 250 ppm zinc (Day 68–110), followed by a commercial finisher diet (Day 111–166), and (E) lecithin: a diet supplemented with 3 g/kg lecithin in the grower and finisher diet (Day 68–166). The effects of lecithin supplementation on compression characteristics of the M. semitendinosus were also studied. These data indicate that there were no significant effects of dietary manipulations on intramuscular fat content. During the grower phase (Day 68–110) pigs offered the low protein:energy and vitamin A-deficient diet had a poorer feed:gain compared with those offered diet containing supplemental sugar. Dietary lecithin supplementation decreased (P < 0.05) hardness and chewiness values for the M. semitendinosus compared with pigs offered the Control diet. Pigs offered the lecithin-supplemented diet also tended (P = 0.090) to have lower cook loss compared with pigs offered the Control diet. Dietary zinc supplementation during the grower phase improved (P < 0.05) the carcass dressing % compared with pigs offered the other diets. Dietary sugar or zinc increased (P < 0.05) the amount of lean in the belly and may be a means to control the rapid rise in the ratio of fat to lean in the belly during the finisher phase. These data indicate that dietary lecithin supplementation has the potential to improve the tenderness of pork but that intramuscular fat is difficult to manipulate nutritionally from an already moderate amount.