RESUMEN
BACKGROUND: There are various fat sources with different energy values and fatty acid compositions that may affect growth performance and carcass composition of grow-finishing pigs. A higher net energy was recently reported in choice white grease compared with soybean oil. Therefore, two experiments were conducted to determine whether practical responses confirm that difference between choice white grease and soybean oil, and to extend the observations to other fat sources. RESULTS: In Exp. 1, pigs fed fats had lower (P < 0.05) average daily feed intake in phase II and overall period, greater (P < 0.05) gain:feed in phase I, phase II, and overall period than pigs fed the control diet. Pigs fed fats tended (P = 0.057) to have thicker backfat depth at the last rib than those fed control. Pigs fed 6% fats had greater (P < 0.01) gain:feed in phase II and overall period than pigs fed 3% fats. During phase I, pigs fed choice white grease grew faster (P < 0.05) than pigs fed soybean oil. In Exp. 2, pigs fed dietary fats (soybean oil, choice white grease, animal-vegetable blend, palm oil, or tallow) had greater (P < 0.01) gain:feed in each phase and overall period, greater (P < 0.01) average daily gain in phase I, but lower (P < 0.01) average daily feed intake in phase II an overall than pigs fed the control diets. The choice white grease also increased (P < 0.05) average daily gain during phase I compared with soybean oil. Pigs fed palm oil had thicker (P < 0.05) backfat depth at the 10th rib than those fed soybean oil, animal-vegetable blend, or tallow. CONCLUSIONS: Inclusion of 6% dietary fat improved feed efficiency of finishing pigs, while different fats produced different practical results that may be consistent with their different energy values. Results from the early stage indicate that dietary fats with relatively more saturated fatty acids may provide greater energy than those with relatively more unsaturated fatty acids for growing pigs.
RESUMEN
The pig is a recognized model for the onset of coronary heart disease and heart attacks. Previous studies have shown that serum cholesterol levels in the pig can be elevated using a high fat, high cholesterol (HFHC) diet. What has been lacking is a genetically defined model corresponding to human ApoE4 susceptibility that can be linked to diets capable of inducing atherosclerosis. This study used a cloned pig model to examine the impact of cholesterol levels with the development of aorta fatty deposits leading to atherosclerosis. Diets were formulated using vegetable sources of protein to provide similar intakes of metabolizable energy, calcium, phosphorous and principal amino acids in both control and HFHC groups. After 60 days, the HFHC group demonstrated a 40-fold increase in aortic fatty streak lesion area combined with 6- and 11-fold increases in total and LDL cholesterol, respectively, over control diet fed cloned pigs. Previous studies have suffered from either imbalanced total caloric intake, an overall imbalance in the nutrition of the control versus HFHC groups or genetic heterogeneity when evaluating dietary constraints related to atherosclerosis. This study demonstrated that cloned, genetically-defined ApoE4 pigs provided balanced nutrition diets provide an experimental system ideally suited to examining atherosclerosis and the onset of coronary heart disease.