Effects of dietary soybean oil on pig growth performance, retention of protein, lipids, and energy, and the net energy of corn in diets fed to growing or finishing pigs.

The objectives of this experiment were 1) to determine if dietary soybean oil (SBO) affects the NE of corn when fed to growing or finishing pigs, 2) to determine if possible effects of dietary SBO on the NE of corn differ between growing and finishing pigs, and 3) to determine effects of SBO on pig growth performance and retention of energy, protein, and lipids. Forty-eight growing (initial BW: 27.3 ± 2.5 kg) and 48 finishing (initial BW: 86.0 ± 3.0 kg) barrows were used, and within each stage of growth, pigs were allotted to 1 of 6 groups. Two groups at each stage of growth served as an initial slaughter group. The remaining 4 groups were randomly assigned to 4 dietary treatments and pigs in these groups were harvested at the conclusion of the experiment. A low-lipid basal diet containing corn, soybean meal, and no added SBO and a high-lipid basal diet containing corn, soybean meal, and 8% SBO were formulated at each stage of growth. Two additional diets at each stage of growth were formulated by mixing 25% corn and 75% of the low-lipid basal diet or 25% corn and 75% of the high-lipid basal diet. Results indicated that addition of SBO had no effects on growth performance, carcass composition, or retention of energy, protein, and lipids but increased (P < 0.05) apparent total tract digestibility of acid hydrolyzed ether extract and GE. Addition of SBO also increased (P < 0.05) DE and NE of diets, but had no effect on the DE and NE of corn. Finishing pigs had greater (P < 0.05) growth performance and retention of energy, protein, and lipids than growing pigs. A greater (P < 0.05) DE and NE of diets was observed for finishing pigs than for growing pigs and the DE and NE of corn was also greater (P < 0.05) for finishing pigs than for growing pigs. In conclusion, addition of SBO increases the DE and NE of diets but has no impact on the DE and NE of corn. Diets fed to finishing pigs have greater DE and NE values than diets fed to growing pigs and the DE and NE of corn are greater for finishing pigs than for growing pigs.

Effects of dietary soybean hulls and wheat middlings on body composition, nutrient and energy retention, and the net energy of diets and ingredients fed to growing and finishing pigs.

The objectives of this experiment were 1) to determine the effect of dietary soybean hulls (SBH) and wheat middlings (WM) on body composition, nutrient and energy retention, and the NE of diets and ingredients fed to growing or finishing pigs and 2) to determine if finishing pigs use the energy in SBH and WM more efficiently than growing pigs. Forty growing barrows (initial BW: 25.4 ± 0.7 kg) and 40 finishing barrows (initial BW: 84.8 ± 0.9 kg) were randomly allotted to 5 groups within each stage of growth. Two groups at each stage of growth served as the initial slaughter group. The remaining pigs were randomly assigned to 3 dietary treatments and harvested at the conclusion of the experiment. The basal diet was based on corn and soybean meal and was formulated to be adequate in all nutrients. Two additional diets were formulated by mixing 70% of the basal diet and 30% SBH or 30% WM. In the growing phase, ADG, G:F, and retention of lipids were greater (P < 0.05) for pigs fed the basal diet than for pigs fed the diets containing SBH or WM. Retention of energy was also greater (P < 0.05) for pigs fed the basal diet than for pigs fed the SBH. In the finishing phase, pigs fed the SBH diet tended (P = 0.10) to have a greater ADG than pigs fed the WM diet, and energy retention was greater (P < 0.05) for pigs fed the basal diet than for pigs fed the WM diet. The NE of the basal diet fed to growing pigs was greater (P < 0.01) than the NE of the diets containing SBH or WM, and there was a tendency for a greater (P = 0.05) NE of the basal diet than of the other diets when fed to finishing pigs. The NE of SBH did not differ from the NE of WM in either growing or finishing pigs, and there was no interaction between ingredients and stage of growth on the NE of diets or ingredients. The NE of diets for growing pigs (1,668 kcal/kg) was not different from the NE of diets for finishing pigs (1,823 kcal/kg), and the NE of the diets containing SBH (1,688 kcal/kg) was not different from the NE of the diets containing WM (1,803 kcal/kg). Likewise, the NE of SBH (603 kcal/kg) did not differ from the NE of WM (987 kcal/kg). In conclusion, inclusion of 30% SBH or WM decreases the performance and nutrient retention in growing pigs but has little impact on finishing pigs. The NE of the diets decreases with the inclusion of SBH and WM, but the NE of diets and ingredients is not affected by the BW of pigs. The NE of SBH is not different from the NE of WM.

Net energy of soybean oil and choice white grease in diets fed to growing and finishing pigs.

The objectives of this experiment were 1) to determine the NE of soybean oil (SBO) and choice white grease (CWG) fed to growing and finishing pigs, 2) to evaluate the effects of inclusion rate of SBO on the NE by growing and finishing pigs, and 3) to determine if there is a difference in the NE of SBO and CWG between growing and finishing pigs. Forty-eight growing (initial BW: 22.13 ± 1.78 kg) and 48 finishing (initial BW: 84.17 ± 5.80 kg) barrows were used, and they were housed and fed individually. Within each stage of growth, pigs were allotted to 8 outcome groups of 6 barrows based on BW. Within each outcome group, pigs were randomly allotted to 1 of 6 groups. Two groups at each stage of growth served as an initial slaughter group. Pigs in the remaining groups were assigned to 4 dietary treatments and slaughtered at the conclusion of the experiment. The basal diet contained corn, soybean meal, and no supplemental lipids. Three additional diets were formulated by mixing 95% of the basal diet and 5% SBO, 90% of the basal diet and 10% SBO, or 90% of the basal diet and 10% CWG. Average daily gain and G:F for finishing pigs and apparent total tract digestibility of energy for growing and finishing pigs increased (linear, P < 0.05) with lipid content, but was not affected by lipid source. The lipid gain:protein gain ratio and the energy retention also increased (linear, P ≤ 0.05) with lipid content in growing and finishing pigs. There were no interactive effects between lipid content and stage of growth or between lipid source and stage of growth on the NE of diets and the NE of dietary lipids. The NE of diets increased (linear, P < 0.01) with increasing SBO (2,056, 2,206, and 2,318 kcal/kg for diets containing 0, 5, or 10% SBO). The NE of the diet containing 10% CWG (2,440 kcal/kg) was greater (P < 0.05) than the NE of the diet containing 10% SBO. The NE of diets was greater (P < 0.05) for finishing pigs than for growing pigs regardless of lipid content or source. The NE of SBO included at 5% (5,073 kcal/kg) was not different from the NE of SBO included at 10% (4,679 kcal/kg), but the NE of CWG (5,900 kcal/kg) was greater (P < 0.05) than the NE of SBO. The stage of growth had no impact on the NE of SBO or CWG. In conclusion, the NE of lipids is not affected by the content of dietary lipids, but the NE of CWG is greater than the NE of SBO.

Effect of virginiamycin on the apparent ileal digestibility of amino acids by growing pigs.

The objective of this experiment was to measure the influence of virginiamycin on the apparent ileal digestibility (AID) of AA by growing pigs. Fifteen barrows were surgically equipped with a T-cannula in the distal ileum and used in the experiment (initial BW = 35.0 +/- 2.7 kg). Animals were randomly allotted to 3 dietary treatments with 5 pigs per treatment during a 6-wk experiment. Dietary treatments included 1) a basal corn-soybean meal diet, 2) the basal diet supplemented with 11 mg/kg of virginiamycin, and 3) the basal diet supplemented with 22 mg/kg of virginiamycin. Pigs were fed their respective treatment diets during wk 2, 3, and 4, but during wk 1, 5, and 6, all pigs were fed the basal diet. Ileal samples were collected on d 6 and 7 of each week. Results showed that the AID of all indispensable AA, except Arg, His, and Ile, increased (P < 0.05) during wk 2, 3, and 4 compared with wk 1 in pigs fed the diet containing 11 mg/kg of virginiamycin. Pigs fed 22 mg/kg of virginiamycin during wk 2, 3, and 4 had increased (P < 0.05) AID of Trp and Val during these weeks compared with the AID in wk 1. However, the increased AID of AA did not carry over to wk 5 and 6, when virginiamycin was withdrawn from the diet, regardless of the inclusion rate. In pooled data from wk 2, 3, and 4, the AID of CP, the mean of all indispensable AA, and Ile, Leu, Met, Phe, Trp, and Val increased (linear, P < 0.05) as virginiamycin was added to the diets, whereas a tendency (P < 0.10) for a linear or quadratic increase was observed for His, Lys, and Thr. These results indicate that addition of virginiamycin to corn-soybean meal diets fed to growing pigs increases the AID of AA, but this effect is not maintained after the removal of virginiamycin from the diet.

Genetic risk factors in diabetic retinopathy.

Diabetic retinopathy is the leading cause of blindness in adults aged 30 to 65 years. However, 20% of the diabetic population does not develop significant retinopathy. To examine the influence of immune-related genetic factors on the development of diabetic retinopathy, we studied immunoglobulin allotypes in 102 subjects aged 8 to 20 years, who had had Type 1 (insulin-dependent) diabetes mellitus for 4.5 to 11 years (mean 7.3 years). HLA had been previously typed on 59 of these subjects. Retinopathy was assessed by expert review of retinal photographs. Among the 44 patients who had evidence of retinopathy, 33(75%) were G2m(23+), while among the 58 patients without retinopathy but with similar duration of disease, only 28(48%) were G2m(23+) (p = 0.006). The HLA-DR types of patients with and without retinopathy were not significantly different. We conclude that there is significant evidence of an association between G2m(23) at the locus encoding IgG2 subclass heavy chains and susceptibility to the development of diabetic retinopathy early in the clinical course of the disease. Our findings provide important independent confirmation of a previous report of association between Gm allotypes and predisposition to diabetic retinopathy. We are unable to determine if the Gm effect on development of retinopathy is due to the G2m(23) allotype itself, or due to genes that are closely linked to, and in linkage disequilibrium with, the locus encoding the G2m(23) allotype.