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.

Effect of corn dried distillers grains with solubles, conjugated linoleic acid, and ractopamine (paylean) on growth performance and fat characteristics of late finishing pigs.

An experiment was performed to evaluate effects of dietary ractopamine, CLA, and corn distillers dried grains with solubles (DDGS) on growth and carcass and fat quality of finishing pigs. This study was conducted as a split-split plot arrangement in a generalized randomized block design. In total 1,102 crossbred barrows and gilts (initial BW = 100.4 kg, SD = 3.7 kg; pic 337 × c22) were randomly assigned to 1 of 8 dietary treatments that consisted of 2 diet sources [corn-soybean meal (corn-soy) and corn-soy + 20% DDGS], 2 levels of ractopamine (0 and 7.4 mg/kg), and 2 levels of CLA (0% and 0.6%). The pen was the experimental unit, with 6 replications per treatment for a total of 48 pens with 23 pigs per pen. Pigs had ad libitum access to water and feed during the 27-d experimental period. Ractopamine addition improved (p < 0.05) ADG and G:F over the control group. Furthermore, carcass weight, carcass yield, loin depth, and lean percentage were increased and back fat depth was decreased (p < 0.05) by feeding ractopamine. Feeding CLA resulted in improved (p < 0.05) ADG and G:F and increased lean percentage but reduced carcass yield (p < 0.05). The inclusion of DDGS did not affect ADG, adfi, or g:f but reduced (p < 0.05) carcass dressing percent. An increase (p < 0.05) in the concentration of pufa was observed with inclusion of DDGS, ractopamine, and CLA. Iodine value (iv) increased (p < 0.001) in both belly and jowl samples by feeding DDGS and ractopamine, whereas a decrease (p < 0.01) was observed when CLA was included in the diets. The fatty acid profiles of belly and jowl fat samples were affected (p < 0.05) by diet source × ractopamine, indicating that effects of dietary ractopamine depend on the fatty acid profile of the diet. These results indicate that feeding ractopamine and CLA could improve growth and carcass measures and that CLA was effective in diminishing some of the negative effects, especially on IV, caused by DDGS.

The effect of corn distiller's dried grains with solubles, ractopamine, and conjugated linoleic acid on the carcass performance, meat quality, and shelf-life characteristics of fresh pork following three different storage methods.

The objective of this study was to evaluate dietary corn distiller's dried grains with solubles (DDGS), ractopamine hydrochloride (RAC), and conjugated linoleic acid (CLA) on growth performance, carcass and fat quality, and shelf-life of fresh pork from finishing pigs. Barrows (n=72) were fed one of eight treatments consisting of two diet sources (corn-soy and corn-soy+20% DDGS), two levels of RAC (0 and 7.4ppm), and two levels of CLA (0 and 0.6%) for 28days. Loins were portioned (n=3) into one of three storage conditions (fresh, cold, frozen); each followed with seven days of retail display. Feeding RAC improved ADG and G:F (P<0.05), whereas DDGS decreased belly fat firmness (P<0.05). Dietary DDGS increased total polyunsaturated fatty acids in jowl and belly samples and increased Iodine Value (IV) (P<0.05), but addition of CLA decreased IV. Dietary DDGS, RAC, or CLA had minimal impact on pork quality following varied storage methods.

Impact of dietary energy level and ractopamine on growth performance, carcass characteristics, and meat quality of finishing pigs.

A total of 54 finishing barrows (initial BW = 99.8 ± 5.1 kg; PIC C22 × 337) reared in individual pens were allotted to 1 of 6 dietary treatments in a 2 × 3 factorial arrangement of treatments with 2 levels of ractopamine (0 and 7.4 mg/kg) and 3 levels of dietary energy (high, 3,537; medium, 3,369; and low, 3,317 kcal of ME/kg) to determine the effects of dietary ractopamine and various energy levels on growth performance, carcass characteristics, and meat quality of finishing pigs. High-energy diets were corn-soybean-meal-based with 4% added fat; medium-energy diets were corn-soybean meal based with 0.5% added fat; and low-energy diets were corn-soybean meal based with 0.5% added fat and 15% wheat middlings. Diets within each ractopamine level were formulated to contain the same standardized ileal digestible Lys:ME (0 mg/kg, 1.82; and 7.4 mg/kg, 2.65 g/Mcal of ME). Individual pig BW and feed disappearance were recorded at the beginning and conclusion (d 21) of the study. On d 21, pigs were slaughtered for determination of carcass characteristics and meat quality. No ractopamine × energy level interactions (P > 0.10) were observed for any response criteria. Final BW (125.2 vs. 121.1 kg), ADG (1.2 vs. 1.0 kg/d), and G:F (0.31 vs. 0.40) were improved (P < 0.001) with feeding of ractopamine diets. Feeding of the low-energy diet reduced (P = 0.001) final BW and ADG compared with the high- and medium-energy diets. Gain:feed was reduced (P = 0.005) when the medium-energy diets were fed compared with the high-energy diets. Additionally, G:F was reduced (P = 0.002) when the low-energy diets were compared with the high- and medium-energy diets. Feeding ractopamine diets increased (P < 0.05) HCW (93.6 vs. 89.9 kg) and LM area (51.2 vs. 44.2 cm(2)). The LM pH decline was reduced (P ≤ 0.05) by feeding ractopamine diets. The feeding of low-energy diets reduced (P = 0.001) HCW when compared with the high- and medium-energy diets and reduced (P = 0.024) 10th-rib backfat when compared with the high- and medium-energy diet. These data indicate that feeding ractopamine diets improved growth performance and carcass characteristics, while having little or no detrimental effect on meat quality. Reductions in energy content of the diet by adding 15% wheat middlings resulted in impaired ADG, G:F, and 10th-rib backfat. There were no ractopamine × energy level interactions in this trial, which indicates that the improvements resulting from feeding ractopamine were present regardless of the dietary energy levels.

Fatty acid profiles and iodine value correlations between 4 carcass fat depots from pigs fed varied combinations of ractopamine and energy.

A total of 54 finishing barrows (initial BW = 99.8 ± 5.1 kg; PIC C22 × 337) reared in individual pens were allotted to 1 of 6 dietary treatments in a 2 × 3 factorial arrangement of treatments with 2 levels of ractopamine (0 and 7.4 mg/kg) and 3 levels of dietary energy (high: 3,537, medium: 3,369, and low: 3,317 kcal/kg of ME) to determine the effects of feeding ractopamine and various dietary energy levels on the fatty acid profile of 4 carcass fat depots (jowl, belly, subcutaneous loin, and intramuscular) and the predictive relationships of calculated iodine value (IV) between these 4 fat depots. Carcasses were sampled for fat tissues at the anterior tip of the jowl, posterior to the sternum on the belly edge, three-quarters the distance around the LM (subcutaneous fat; SC), and within the LM (intramuscular fat; IMF). Feeding ractopamine diets reduced (P < 0.05) total SFA in SC and IMF and increased (P = 0.04) total MUFA in SC. Also, feeding ractopamine diets increased (P < 0.01) the IV of IMF. Total MUFA of belly fat was reduced (P < 0.05) when the low-energy diet was fed compared with the high-energy diet. Jowl fat total MUFA was reduced (P < 0.05) and total PUFA was increased (P < 0.05) when the medium-energy diet was fed compared with the high- and low-energy diets. Iodine values, independent of treatment, were 60.97, 64.51, 55.59, and 58.26 for belly, jowl, IMF, and SC fat depots, respectively. The IV correlations within fat depots were not consistent across dietary treatments because of the effect of treatments on carcass fatty acid characteristics. Feeding ractopamine diets shifted the fatty acid profile from SFA to MUFA in the SC depot. Feeding ractopamine diets did not change belly fat profiles, thus avoiding the potential negative effect of softening belly fat, which is detrimental to processing value. The IV of one fat depot may not be a good indication of IV of other fat depots because of weak correlation coefficients and the apparent influence of dietary treatment.

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.

Fresh meat and further processing characteristics of ham muscles from finishing pigs fed ractopamine hydrochloride.

Ractopamine hydrochloride (RAC) has consistently led to an advantage in carcass cutting yields of finishing pigs and remains a common feed additive in US finishing pig diets. Less is known about the effect of RAC on further processing characteristics. Some researchers have reported advantages in ultimate pH of the LM in pigs fed RAC. If a greater ultimate pH was also observed in hams, the increased pH could affect further processing characteristics and lead to better protein interaction and improved textural properties. The objective of this experiment was to determine if RAC-fed pigs yielded hams with a greater ultimate pH, and if so, whether or not that advantage improves textural properties and water retention of further processed hams. Two hundred hams from barrows and gilts fed RAC or control diets were selected based on HCW. Hams were fabricated into 5 separate pieces to determine cutting yields, and 6 muscles were evaluated for ultimate pH. Hams were processed to make cured and smoked hams. Ractopamine increased cutting yields of the whole ham (P < 0.0001), inside (P < 0.01), outside (P < 0.01), and knuckle (P < 0.01) when expressed as a percentage of chilled side weight. Ultimate pH of the rectus femoris, vastus lateralis, and semitendinosus were all 0.06 pH units greater (P < 0.05), the biceps femoris was 0.04 pH units greater (P = 0.02), and the semimembranosus and adductor muscles were 0.03 pH units greater in pigs fed 7.4 mg/kg of RAC when compared with control pigs. Cured hams from RAC-fed pigs were heavier at all stages of production. No differences were detected in binding strengths (P = 0.88) or protein fat-free values (P = 0.13) between RAC (9.06 kg and 20.37) and control hams (9.01 kg and 20.13). Ractopamine increased cutting yields, total weight of cured hams, and ultimate muscle pH. Ractopamine can be fed to pigs to achieve the desired growth characteristic advantages and cutting yields without affecting further processed ham characteristics.

Amino acid digestibility and energy concentration in a novel source of high-protein distillers dried grains and their effects on growth performance of pigs.

Three experiments were conducted to evaluate a novel source of high-protein distillers dried grains produced by Buhler Inc. (HP-DDG(Buhler)) and fed to growing pigs. The standardized ileal digestibility (SID) of AA in HP-DDG(Buhler) and in soybean meal (SBM) was determined in Exp. 1. Nine pigs (109.8 +/- 2.78 kg of BW) were fitted with a T-cannula in the distal ileum and allotted to a triplicated 3 x 3 Latin square design with 3 diets and 3 periods per square. Diets containing HP-DDG(Buhler) or SBM as the only source of AA and an N-free diet were formulated. The SID of indispensable AA was less (P < 0.01) in HP-DDG(Buhler) than in SBM (Arg, 87.5 vs. 93.9%; His, 76.7 vs. 88.7%; Ile, 76.4 vs. 87.5%; Leu, 77.8 vs. 86.8%; Lys, 75.4 vs. 88.4%; Met, 82.8 vs. 88.4%; Phe, 77.9 vs. 87.3%; Thr, 72.5 vs. 83.5%; Trp, 85.1 vs. 91.0%; Val, 73.3 vs. 84.3%). The DE and ME in HP-DDG(Buhler) and in corn were measured in Exp. 2 using 16 growing barrows (24.6 +/- 1.66 kg of BW). A corn-based diet and a diet containing 50% corn and 48.2% HP-DDG(Buhler) were formulated. The total collection method and the difference procedures were used. The concentrations of DE and ME in HP-DDG(Buhler) were greater (P < 0.001) than in corn (5,043 vs. 4,002 kcal/kg of DM and 4,690 vs. 3,921 kcal/kg of DM, respectively). Experiment 3 was a 9-wk growth assay using 40 pigs (initial BW: 58.2 +/- 2.28 kg) allotted to 5 dietary treatments, with 8 replicates of individually housed pigs per treatment. Treatments included a control diet based on corn and SBM and 4 diets in which HP-DDG(Buhler) replaced 33, 66, 66, or 100% of the SBM in the control diet. All HP-DDG(Buhler) diets contained supplemental Lys and Thr to provide similar concentrations of SID Lys and Thr in all diets; one of the diets in which HP-DDG(Buhler) replaced 66% of the SBM and the diet in which HP-DDG(Buhler) replaced 100% of the SBM also contained crystalline Trp. Dietary treatments had no effect on ADG (1.15, 1.13, 1.16, 1.12, and 1.14 kg), ADFI (3.33, 3.35, 3.39, 3.30, and 3.33 kg), or G:F (0.35, 0.34, 0.34, 0.34, and 0.34 kg/kg). Carcass traits of pigs fed the diet in which HP-DDG(Buhler) replaced 100% of the SBM were not different from those of pigs fed the control diet. In conclusion, HP-DDG(Buhler) contains more DE and ME than corn, but has decreased SID values for AA compared with SBM. Soybean meal can be replaced by HP-DDG(Buhler) in diets fed to finishing pigs without any effect on growth performance or carcass characteristics, provided that diets are adequate in indispensable AA.

Effect of feeding reduced crude protein and phosphorus diets on weaning-finishing pig growth performance, carcass characteristics, and bone characteristics.

Two experiments were conducted to determine the effects of feeding a corn- and soybean meal-based diet (control) or a low nutrient excretion (LNE) diet, formulated with reduced dietary CP and additional synthetic AA, low phytic acid corn, and phytase, on pig growth performance during the grower (BW=32 to 77 kg) and finisher (BW=78 to 126 kg) periods and on carcass and bone characteristics at slaughter. Pigs (32+/-1.3 kg of BW, Exp. 1; 6.7+/-0.27 kg of BW, Exp. 2) were blocked by sex and BW and randomly allotted to a control or LNE diet. Pigs were housed in 4 rooms during the nursery period and in 2 rooms during the grower and finisher periods, with individual and identical ventilation systems. Pigs were phase fed 3 nursery diets for 5 wk (Exp. 2) and phase fed 2 grower and 2 finisher diets for 16 wk (Exp. 1 and 2). Pigs were housed 4 or 5 pigs/pen with 9 pens x sex(-1) x treatment(-1) during the nursery period and 4 or 5 pigs/pen with 5 pens x sex(-1) x treatment(-1) in the grower phase and 2 or 3 pigs/pen in the finisher phase. Individual BW and pen feed disappearance were recorded weekly in the nursery period and every 2 wk in the grower-finisher period. Pigs were scanned ultrasonically at d 34 of the nursery period and wk 8 and 16 of the grower-finisher period to determine backfat depths and LM area. Ten pigs x sex(-1) x treatment(-1) were slaughtered at wk 16 of each experiment to determine carcass characteristics. Overall growth performance was not different during each experiment. However, nursery G:F (control=0.65; LNE=0.60), grower ADG (Exp. 1 and 2), and grower G:F (Exp. 2) were reduced (P<0.05) when the LNE diets were fed. Diet had no effect on 10th-rib carcass data in either experiment. Metatarsal bone ash percentage was reduced (P<0.05) when the LNE diets were consumed in both experiments. Feeding LNE diets resulted in the maintenance of overall growth performance, bone variables, and carcass characteristics. However, further refinements are still required in the nursery and grower phases of pig production to optimize LNE diet use by the swine industry.

Effects of water and diet acidification with and without antibiotics on weanling pig growth and microbial shedding.

Two 5-wk experiments were conducted to determine the effects of water and diet acidification with and without antibiotics on weanling pig growth performance and microbial shedding. In Exp. 1, 204 pigs (19.2 d of age) were used in a 3 x 2 factorial, with 3 dietary treatments fed with or without water acidification (2.58 mL/L of a propionic acid blend; KEM SAN, Kemin Americas, Des Moines, IA). Dietary treatments were: 1) control, 2) control + 55 ppm of carbadox (CB), and 3) dietary acid [DA; control + 0.4% organic acid-based blend (fumaric, lactate, citric, propionic, and benzoic acids; Kemin Americas)] on d 0 to 7 followed by 0.2% inorganic acid-based blend (phosphoric, fumaric, lactic, and citric acids; Kemin Americas) on d 7 to 34. In Exp. 2, 210 pigs (average 18.3 d of age) were fed 1 of 3 dietary treatments: 1) control, 2) control + 55 ppm of CB, and 3) control + 38.6 ppm of tiamulin + 441 ppm of chlortetracycline on d 0 to 7 followed by 110 ppm of chlortetracycline on d 7 to 35 (TC) with or without dietary acidification (same as Exp. 1) in a 3 x 2 factorial arrangement of treatments. For both experiments, the pigs were allotted based on genetics, sex, and initial BW [5.5 kg (Exp. 1) or 5.6 kg (Exp. 2)]. Pigs were housed at 6 or 7 (Exp. 1) and 7 (Exp. 2) pigs/pen. Treatments were fed in 3 phases: d 0 to 7, 7 to 21, and 21 to 35 (34 d, Exp. 1). Fecal grab samples were collected from 3 pigs/pen on d 6, 20, and 33 for measurement of pH and Escherichia coli. During phase 3 and overall in Exp. 1, pigs fed CB had greater (P < 0.001) ADG (overall ADG, 389 vs. 348, and 348 g/d, respectively), ADFI (P < 0.007, 608 vs. 559, and 554 g/d, respectively), and d 34 BW (P < 0.001, 18.8 vs. 17.3, and 17.3 kg, respectively) than pigs fed NC and DA. Phase 3 ADG was improved (P < 0.01) by water acidification across all diets. In Exp. 2, pigs fed CB and TC had greater ADG (P < 0.004; 315 and 303 vs. 270 g/d, respectively), ADFI (P < 0.01), and d 35 BW (P < 0.002; 16.7 and 16.2 vs. 15.1 kg, respectively) than pigs fed NC. There was a tendency (P < 0.08) for an improvement in ADG when DA was added to the NC or TC, but decreased ADG when DA was added to CB.

Effects of Acid LAC and Kem-Gest acid blends on growth performance and microbial shedding in weanling pigs.

Weanling pigs with mean initial BW of 6.04 kg (Exp.1) and 5.65 kg (Exp. 2) and mean age at weaning of 18.2 d (Exp. 1) and 17.7 d (Exp. 2) were used in two 5-wk experiments (Exp. 1, n = 180; Exp. 2, n = 300) to evaluate the effects of an organic acid blend (Acid LAC, Kemin Americas Inc., Des Moines, IA) and an inorganic/organic acid blend (Kem-Gest, Kemin Americas Inc.) on weanling pig growth performance and microbial shedding. In Exp. 1, the 5 dietary treatments were 1) negative control, 2) diet 1 + 55 ppm carbadox, 3) diet 1 + 0.4% Acid LAC, 4) diet 1 + 0.2% Kem-Gest, 5) diet 1 + 0.4% Acid LAC and 0.2% Kem-Gest. In Exp. 2, the 6 dietary treatments were diets 1 through 4 corresponding to Exp. 1, plus 5) sequence 1: 0.4% Acid LAC for 7 d followed by 0.2% Kem-Gest for 28 d, and 6) sequence 2: 0.2% Kem-Gest for 7 d followed by 0.4% Acid LAC for 28 d. Pigs were housed at 6 (Exp. 1) or 10 (Exp. 2) pigs/pen. Treatments were fed throughout the experiment in 3 phases: d 0 to 7, d 7 to 21, and d 21 to 35. In Exp. 1, there were no differences (P > 0.05) in ADG, ADFI, or G:F among the dietary treatments at any time during the study. In Exp. 2, throughout the study, pigs fed carbadox (diet 2) and sequence 1 (diet 5) diets had the greatest ADG (d 0 to 35; 262, 294, 257, 257, 292, and 261 g/d, diets 1 through 6, respectively; P < 0.05), greater ADFI than all other acid treatments (P < 0.05), and tended to have greater ADFI than diet 1 (P < 0.10). Fecal pH, Escherichia coli concentrations, and Salmonella presence were determined at d 6, 20, and 34 for Exp. 1, and on d 32 for Exp. 2. For both experiments, there was no effect of treatment on the presence of fecal Salmonella (P > 0.10) at any sampling time. In Exp. 1, fecal E. coli concentrations for pigs fed the carbadox (P < 0.05) diet were greater than for pigs fed the combination diet with 0.4% Acid LAC and 0.2% Kem-Gest on d 34, and the pigs fed the negative control diet tended (P < 0.10) to have greater fecal E. coli concentrations than those fed the combination diet on d 34. In Exp. 2, fecal pH of pigs fed sequence 1 tended to be greater than fecal pH of pigs fed diet 1, diet 4, or sequence 2 (P < 0.10), but there was no dietary effect on fecal E. coli. In Exp. 1, growth performance of pigs fed the Acid LAC and Kem-Gest diets was similar to each other and to that of the carbadox-fed pigs. Adding the combination of 0.4% Acid LAC and 0.2% Kem-Gest to nursery pig diets reduced ADFI and pig growth rate. In Exp. 2, pigs fed the acid sequence of Acid LAC-Kem-Gest had similar growth performance to pigs fed carbadox, and this novel dietary acid sequence may have merit as a replacement for antibiotics in the nursery phase.