Comparative digestibility and lipogenic activity in Landrace and Iberian finishing pigs fed ad libitum corn- and corn-sorghum-acorn-based diets

Forty-eight finishing castrated male pigs (24 Iberian and 24 Landrace; 88.4 kg LW) were fed two diets differing in main carbohydrates sources, corn- (Diet C) or corn-sorghum-acorn (Diet A). After 28 days of experimental period, 24 animals (six per treatment) were slaughtered and digesta and carcass sampled to study digestion and lipogenesis activity. Iberian pigs showed a higher voluntary feed intake than Landrace pigs (3.5 vs. 2.7 kg/day; P < 0.01), but no significant differences in the daily weight gain. Between diets, no significant differences were observed in the production data. However, the whole-tract digestibility was significantly lower with Diet A than with Diet C for OM, CP and monosaccharides. Whole-tract apparent digestibility of Iberian pigs was also significantly lower than of Landrace (P < 0.01), especially for those animals fed Diet A. As a result of feed intake and digestibility coefficients, Iberian pigs showed a higher intake of digestible OM (2910 g/day) than Landrace (2310 g/day), which was associated with higher (P < 0.05) backfat thickness, muscle fat content and lipogenic enzyme activities. Lipogenesis was not broadly influenced by the dietary treatments, except a significant decrease in the intermuscular adipose tissue with diet A. We conclude that digestibility and lipogenic enzyme activities were markedly influenced by the animal breed and to a lesser extent by the diet. © 2002 Elsevier Science B.V. All rights reserved.