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The effects of feeding corn fines (screenings) containing mycotoxin levels at greater than the FDA cautionary levels were evaluated using crossbred pigs [n = 150, 90 barrows and 60 gilts; mean initial body weight (BW) = 6.42 ± 0.06 kg; n =] that were blocked by BW and sex, randomly allotted within block to 6 dietary treatments, and housed 5 pigs/pen resulting in a total of 5 replicates. The corn fines used in this study contained mycotoxin levels that were analyzed to be 20,334 ppb total fumonisin, 1,499 ppb zearalenone, and 5,075 ppb total deoxynivalenol. The corn fines were added into a corn-soybean meal basal diet at 0, 20, 40, and 60% total dietary corn fines (Diets 1-4, respectively). Diet 5 was created by adding 40 ppm of boron (as sodium tetraborate decahydrate, 11.34% B) to Diet 4. Diet 6 was created by adding 0.25% Biofix Plus with FUMzyme (DSM Nutritional Products, Parsippany, NJ) to Diet 4. Dietary treatments were fed for a total of 6 weeks; thereafter, all pigs received a common corn-soybean meal basal diet without fines for about 2 weeks. Data were analyzed by ANOVA using the GLM procedure of SAS with the pen being the experimental unit. Orthogonal polynomial contrasts were used to determine linear and quadratic effects with increasing dietary levels of corn fines in Diets 1-4 as well as preplanned single degree of freedom comparisons. Increasing fines linearly decreased ADG during week 1-6 (P= 0.03), as well as linearly decreased gain/feed ratio during week 1-6 (P= 0.04; Table 1). Comparing Diets 4 and 5 to Diet 1 during week 1-6, there was a decrease in ADG and gain/feed ratio (P< 0.05) but no effect on ADFI (P> 0.05); subsequently, the difference in Diets 4 and 5 compared with Diet 1 was no longer significant for week 1-8. Comparing Diet 6 to Diets 1 and 4 during week 1-6, pigs fed Diet 6 were able to recover 57% of the lost ADG and 30% of the lost BW gain/feed ratio that occurred when corn fines were increased from 0 to 60%. During week 6-8 (all pigs on a common diet), pigs on Diet 5 and 6 had an increase in ADG compared with Diet 1. In conclusion, as mycotoxins increased pigs exhibited negative effects on ADG and gain/feed ratio but the enzyme FUMzyme ameliorated a portion of these effects. Further, the recovery from week 6-8 from all pigs does show the importance of feeding clean corn to optimize ADG, ADFI and gain/feed ratio.

Six female littermate pairs were used in an experiment to evaluate the mRNA expression in tissues from piglets given one or two 1 mL injections of iron dextran (200 mg Fe/mL, Uniferon, Pharmacosmos Inc. Watchung, NJ). All pigs in the litter were administered the first 1 mL injection < 24 hours after birth and on d 7, pigs were paired by body weight (BW; 1.72 ± 0.13 kg) and one pig from each pair was randomly selected as control (CON) and the other received a second injection (+Fe). At weaning on d 22, each piglet was anesthetized, and samples of liver and duodenum were taken from the anesthetized piglets and placed in DNA/RNA Shield (Zymo, Irvine, CA) for preservation until mRNA extraction. RNA-Seq libraries were sequenced to a depth of at least 30 million read pairs (150 bp paired-end sequencing) per sample. Differential Gene Expression data were analyzed with GeneSpring (Agilent, Santa Clara, CA) with a fold-change (FC) of |1.2| P< 0.05 (Table 1). Pathway analysis was conducted with Ingenuity Pathway Analysis (IPA QIAGEN, Redwood City, CA) software with Z-score cutoff of P< 0.05. In the duodenum 435 genes were significantly changed with a FC ≥|1.2| P< 0.05. Most notably, Claudin 1 and Claudin 2 were inversely affected by the second dose of iron. Claudin 1 (CLDN1, FC = 4.48, P = 0.0423) is responsible for cell-to-cell adhesion in the epithelial cell sheets and serves as a barrier to prevent water and solutes from passing through the paracellular space. Claudin 2 (CLDN2, FC = -1.41, P= 0.0097) was down regulated because it is expressed in cation leaky epithelia. In the liver 362 genes were expressed with a FC ≥|1.2| P< 0.05. The gene most affected by a second dose of 200 mg Fe was HAMP (Hepcidin Antimicrobial Peptide) with an FC of 40.8. HAMP is a liver-produced hormone that is the main circulating regulator of Fe absorption and distribution across tissues. It also controls the major flows of Fe into plasma by promoting endocytosis and degradation of ferroportin (SLC4A1). This leads to the retention of Fe in Fe-exporting cells and decreased flow of Fe into plasma. Metabolic pathway changes in the duodenum and liver provide evidence for the improved feed conversion and growth rates in pigs given two iron injections pre-weaning. In the duodenum, there is a down regulation of gluconeogenesis (P< 0.05). Concurrently, there is a decrease in the production of urea in the liver (P< 0.05). These observations show that there is less need for gluconeogenesis, thus less urea production from deaminated amino acids. The genomic and pathway analyses provided empirical evidence linking gene expression with phenotypic observations of piglet health and growth improvements.

Mycotoxins in feed are known to negatively affect growth and other physiological processes in pigs. Two experiments were conducted to investigate the effects of feeding diets with varying levels of mycotoxins and boron (a nutrient reported to mitigate some aspects of mycotoxicosis). Screenings from the 2020 crop year corn contained mycotoxin levels of 23,038 ppb total fumonisin, 1,446 ppb zearalenone, and 5,032 ppb total deoxynivalenol (DON)l. The corn fines were added into a corn-soybean meal diet formulated to meet or exceed NRC (2012) nutrient requirements as a replacement for corn at 0, 10, and 20% for Diets 1-3. Diets 4-6 were Diets 1-3, respectively, plus 40 ppm boron from sodium tetraborate decahydrate (11.34% B). Diets 3 and 6 were formulated to approximate the cautionary levels of fumonisin and DON stated by the FDA. Exp. 1 used crossbred pigs (n = 144; mean initial BW = 10.20 ± 0.23 kg) blocked by sex and BW and randomly allotted to dietary treatments for a total of 6 replicates (4 pigs/pen) for a 21-day growth performance trial. On day 21, serum was collected from the heaviest and lightest pig in each pen for clinical chemistry assessment. Exp. 2 used crossbred pigs (n = 48; mean initial BW = 9.18 kg ± 0.12 kg) blocked by sex and BW and randomly allotted to 1 of 3 treatment comparisons including: Comparison 1) Diet 1 vs. Diet 2; Comparison 2) Diet 1 vs. Diet 3; and Comparison 3) Diet 2 vs. Diet 3. There were a total of 4 replicates (4 pigs/pen) for a 21-day preference trial. Performance and clinical chemistry data were analyzed by ANOVA using the GLM procedure of SAS with pen as the experimental unit. Preference data were evaluated via t-test. Increasing mycotoxin levels in Exp. 1 had no effect on overall ADG, ADFI, and GF (Table 1; P= 0.16, 0.53, and 0.92, respectively). The increasing mycotoxin levels did effect glucose and cholesterol (P= 0.03, and P< 0.01, respectively). There was no effect of boron on the same performance measures (P= 0.81, 0.59, and 0.76, respectively) although it did decreaser serum glucose (P= 0.02). Exp. 2 demonstrated the barrows ability to discern between diets in Comparisons 2 and 3 (P< 0.01) for each week while gilts only started to exhibit that ability during Week 3 for Comparison 2 (P= 0.06). In conclusion, pigs can differentiate and choose between diets containing these mixed mycotoxins but when not given a choice, the pigs do not have different growth performance using the particular mycotoxins and within the framework of this assessment.

An experiment was conducted to evaluate the effects of an additional injection of iron dextran (Uniferon, Pharmacosmos Inc.) administered at d 6 to 8 of age. Crossbred pigs [n = 144; equal barrows and gilts; initial body weight (BW) = 2.86 ± 0.01 kg] from 21 litters were assigned to either the control (CON) or an added-injection treatment (+Fe). Pigs were paired by sex and BW within a litter and randomly assigned to the iron treatment within each pair. All pigs had received a 200 mg Fe intramuscular (IM) injection < 24 h after birth. All pigs were weaned at 22 to 24 days, housed 6 pigs/pen for a total of 12 pens/treatment, and received a common corn-soybean meal diet formulated to meet or exceed the NRC (2012) requirement estimates relative to BW until slaughter. Body weight and feed disappearance were recorded at least biweekly to determine average daily gain (ADG) and feed intake (ADFI). Hemoglobin (Hb) concentrations were measured at birth, initiation of experiment (d 6 to 8), weaning, and at the end of the nursery and finisher periods. At the time of slaughter, 1 pig/pen (n = 12 pigs/treatment) was selected and slaughtered for carcass characteristic measures. Data were subjected to ANOVA by the GLM procedure of SAS; the individual pig served as the experimental unit for BW, Hb, ADG, and carcass characteristics whereas pen served as the experimental unit for ADFI, and gain/feed ratio data. The statistical model included sex, treatment, sex × treatment, and allotment pair for Hb and ADG. There were expected sex effects for ADG but no sex × treatment interactions for any response measures. The +Fe pigs had a greater Hb at weaning (13.1 vs. 10.7 g/dL, P< 0.0001) and end of the nursery (12.1 vs. 11.7 g/dL, P= 0.01) compared with CON pigs (Table 1). During the finisher period, +Fe pigs had a greater ADG (P= 0.05) compared with CON pigs. Overall, pigs receiving the added iron injection had an ~ 4% increase in ADG (P= 0.04) from weaning to slaughter. The cumulative improvement in ADG from weaning to slaughter observed for +Fe group resulted in +Fe pigs having a heavier BW at the end of the experiment (115.77 vs. 112.79 kg; P= 0.04). Following slaughter, +Fe pigs had ~ 2.5% heavier cold carcass weight (82.99 vs. 80.93 kg; P= 0.34) and trimmed loin (10.67 vs. 9.95 kg; P= 0.04) compared with the CON pigs. In conclusion, administering an additional iron injection resulted in greater Hb at weaning and the end of the nursery as well as improved growth performance from weaning to slaughter weight and increased carcass measures at slaughter.

Six female littermate piglets were used in an experiment to evaluate the mRNA expression in tissues from piglets given one or two 1 mL injections of iron dextran (200 mg Fe/mL). All piglets in the litter were administered the first 1 mL injection < 24 h after birth. On day 7, piglets were paired by weight (mean body weight = 1.72 ± 0.13 kg) and one piglet from each pair was randomly selected as control (CON) and the other received a second injection (+Fe). At weaning on day 22, each piglet was anesthetized, and samples of liver and duodenum were taken from the anesthetized piglets and preserved until mRNA extraction. differential gene expression data were analyzed with a fold change cutoff (FC) of |1.2| P < 0.05. Pathway analysis was conducted with Z-score cutoff of P < 0.05. In the duodenum 435 genes were significantly changed with a FC ≥ |1.2| P< 0.05. In the duodenum, Claudin 1 and Claudin 2 were inversely affected by + Fe. Claudin 1 (CLDN1) plays a key role in cell-to-cell adhesion in the epithelial cell sheets and was upregulated (FC = 4.48, P= 0.0423). Claudin 2 (CLDN2) is expressed in cation leaky epithelia, especially during disease or inflammation and was downregulated (FC = −1.41, P= 0.0097). In the liver, 362 genes were expressed with a FC ≥ |1.2| P< 0.05. The gene most affected by a second dose of 200 mg Fe was hepcidin antimicrobial peptide (HAMP) with a FC of 40.8. HAMP is a liver-produced hormone that is the main circulating regulator of Fe absorption and distribution across tissues. It also controls the major flows of Fe into plasma by promoting endocytosis and degradation of ferroportin (SLC4A1). This leads to the retention of Fe in Fe-exporting cells and decreased flow of Fe into plasma. Gene expression related to metabolic pathway changes in the duodenum and liver provides evidence for the improved feed conversion and growth rates in piglets given two iron injections preweaning with contemporary pigs in a companion study. In the duodenum, there is a downregulation of gene clusters associated with gluconeogenesis (P< 0.05). Concurrently, there was a decrease in the mRNA expression of genes for enzymes required for urea production in the liver (P< 0.05). These observations suggest that there may be less need for gluconeogenesis, and possibly less urea production from deaminated amino acids. The genomic and pathway analyses provided empirical evidence linking gene expression with phenotypic observations of piglet health and growth improvements.1. Pigs that received two injections of iron-dextran before 2 wk of age were numerically heavier and exhibited greater blood Hb concentrations at weaning.2. Administering a second iron injection resulted in changes in the expression of 362 genes in the liver and 435 genes expressed in small intestine.Iron deficiency anemia (IDA) in neonatal piglets is a problem that occurs unless there is intervention with exogenous iron. The most common method to prevent IDA is with an iron injection within 48 h of birth. However, the iron from the first injection will only support normal iron status in the piglets for ~4 kg of growth. As a result, with faster-growing piglets and larger litters, many piglets weaned today are iron deficient which results in slower growth and poor immunity. Pigs never fully recover nor grow at the same rate as those that have sufficient iron status. The aim of this study was to evaluate the effects of one or two injections of iron dextran on the differences in gene expression and metabolic pathway changes in the small intestine and liver of nursing piglets. At weaning, samples of liver and duodenum underwent genome-wide RNA sequencing. The data obtained were statistically analyzed to determine which genes and metabolic pathways were affected. There were 362 and 435 genes significantly changed in the liver and duodenum, respectively, due to a second dose of iron dextran on day 7 after birth.

An experiment was conducted to evaluate the effects of a second injection of iron dextran administered on days 6 to 8 of age. A total of 144 crossbred pigs (equal barrows and gilts; initial age 6 to 8 d; initial body weight [BW] = 2.86 ± 0.01 kg) were assigned to either the control (CON) or an added-injection treatment (+Fe). Pigs were paired by sex and BW within a litter and randomly assigned to the iron treatment within each pair. All pigs had received an initial intramuscular (IM) injection of iron dextran (200 mg Fe) <24 h after birth. Pigs assigned to the +Fe treatment received a second IM injection of iron dextran (200 mg Fe) on days 6 to 8. All pigs were weaned at 22 to 25 d, housed 6 pigs/pen, and received a common corn–soybean meal diet. BW and feed disappearance were recorded every 2 wk. Hemoglobin (Hb) concentrations were measured at birth, initiation of experiment (days 6 to 8), weaning, and the end of the nursery and end of the study. At the end of the study, 1 pig/pen (n= 12 pigs/treatment), closest to the pen mean was selected and slaughtered for carcass characteristic measures. The individual pig served as the experimental unit for BW, Hb, average daily gain (ADG), and carcass characteristic data whereas the pen served as the experimental unit for average daily feed intake, and gain/feed ratio data. The +Fe pigs had a greater Hb at weaning (13.1 vs. 10.7 g/dL, respectively; P <0.01) and end of the nursery (12.1 vs. 11.7 g/dL, respectively; P= 0.01) compared to CON pigs. During the finisher period, +Fe pigs had a greater ADG (0.94 vs. 0.91 kg, respectively; P= 0.05) compared to CON pigs. Overall, pigs receiving the second iron injection had an ~4% increase in ADG (P= 0.04) from weaning to the end of study. The cumulative improvement in ADG from weaning to the end of study observed for +Fe group resulted in +Fe pigs having a heavier BW at the end of the study (~3 kg; P= 0.04). Following slaughter, +Fe pigs had ~7.2% heavier trimmed loin (P= 0.04) compared to the CON pigs. In conclusion, administering a second iron injection resulted in greater Hb at weaning and the end of the nursery as well as improved growth performance from weaning to the end of study weight and increased carcass weight at slaughter.Administering a second iron injection to pigs before weaning resulted in greater Hb levels at weaning and the end of the nursery period.Average daily gain from weaning to slaughter was greater for pigs receiving a second iron injection compared to only the initial injection at litter processing.The study aimed to evaluate the effects of a second iron dextran injection administered to piglets before weaning on hemoglobin concentration (Hb), growth performance, and carcass measures. Treatments included: a single iron injection administered within 24 h after birth (CON) and two iron injections (+Fe), one administered within 24 h after birth followed by a second iron injection administered 6 to 8 d after birth. Administering a second iron injection before weaning resulted in increased Hb at weaning and the end of the nursery period. Furthermore, pigs receiving a second iron injection had a greater average daily gain from weaning to final market weight which resulted in a final bodyweight difference of ~3 kg. The increased slaughter weight observed for pigs receiving a second iron injection was associated with an increase in trimmed loin yield. In the current study, providing a second iron injection before weaning was a practical method to improve weaning Hb in early life and resulted in a faster overall growth from weaning to the end of the study.

A cooperative study utilizing 514 weanling pigs from 7 experiment stations was conducted to determine the effects of an additional iron injection administered to piglets before weaning on growth performance and hematological measures. All pigs received an initial iron injection at the time of processing postfarrowing. At each station, pigs were assigned to either the control or an added-injection treatment by pairing two same-sex pigs with a BW difference ≤ 0.453 kg within a litter. One pig within each pair received the additional iron injection (same dose received at processing) 3 to 5 days preweaning. Once weaned, both the control and added-injection group received common station-specific nursery diets. Body weight was recorded weekly by all stations. Blood samples were also collected at second injection, weaning, 14 and 28 days postweaning by 3 of the 7 stations. All data were subjected to ANOVA with the model containing the terms treatment, station, and treatment by station interaction. Average daily gain (Table 1) was greater for the added-injection group during d 0 to 14 (212.5 vs. 202.6 g, P = 0.03) which resulted in an increase in d 14 BW (P = 0.05). Although there was no treatment effect for overall ADG (d -4 to d 28), the tendency for a treatment by station interaction (P = 0.09) illustrated both responsive and nonresponsive stations, indicating that iron status was not the most limiting factor for growth at all stations. Hemoglobin concentration was greater (P < 0.0001) for the added-injection group at weaning and d 14 postweaning. In conclusion, an additional iron injection administered before weaning may lead to early success in the nursery resulting in a heavier BW in subsequent periods; however, the beneficial effects of an additional iron injection are likely dependent on herd status and characteristics.

An experiment was conducted to evaluate the effects of boron (B) supplemented to a corn-soybean meal diet on apparent digestibility and retention of nutrients in growing barrows. A total of 24 barrows (mean initial BW = 61.15 ± 2.45 kg) were allotted to 3 dietary treatments with 8 replicates. Dietary treatments consisted of 0, 5, and 25 mg B/kg diet as sodium tetraborate decahydrate (Na2B4O7∙10 H2O; 11.34% B) which were fed from weaning onward. Barrows underwent a 5-7 d adaptation period to the meal allowance and metabolism crate which was followed by a 5-d total fecal and urine collection using the marker to marker method. Barrows were fed at 2.7% of their metabolic BW (2.7 x maintenance ME needs [2.7 × 106 Kcal ME/kg BW0.75]) during the adaptation and collection periods in a gruel form (feed:water, 1:1 wt/vol). Data were analyzed using the Proc GLM procedure of SAS with the individual pig as the experimental unit. Supplemental B did not affect (P> 0.05) energy, lipid, nitrogen, calcium, or phosphorus apparent digestibility and retention. However, there was a linear increase observed in both magnesium absorption (P= 0.01; 0.24, 0.26, and 0.32 g/d, respectively) and digestibility (P= 0.04; 22.35, 23.56, and 28.49 %, respectively) to increasing B supplementation. Absolute retention of magnesium did not differ (P> 0.05; 0.13, 0.14, and 0.17 g/d, respectively). In conclusion, supplementing B at 5 and 25 mg B/kg diet resulted in an increase in magnesium absorption and digestibility with no adverse effects observed on apparent digestibility and retention of other nutrients.

A 49-d experiment evaluated the effects of supplemental boron (B) on growth, and serum insulin and glucose concentration of pigs. Crossbred pigs [n = 48; initial body weight (BW) 19.18 ± 0.29 kg] were randomly allotted to 1 of 4 diets based on BW and sex. Diets were corn-SBM-based, formulated to meet NRC (2012) nutrient requirement estimates, and were supplemented with 0, 25, 50, or 100 mg B/kg diet as sodium tetraborate decahydrate. On d 20 and 41, blood samples were collected. Fasting samples were collected following an overnight fast; then a postprandial sample was taken approximately 50 minutes after the pigs had 10 minutes of ad libitum access to feed. Samples were processed and serum analyzed for insulin and glucose concentration. Increasing B levels resulted in a linear decrease for overall ADG (0.87, 0.86, 0.85, and 0.82 kg, P = 0.02). On d 20, supplemental B resulted in a quadratic response on fasting serum glucose concentration (5.25, 4.80, 4.65, and 5.01, P = 0.03) and a linear decrease in postprandial serum insulin concentration (29.1, 25.5, 18.2, and 18.1 µU/mL, P = 0.02). Furthermore, there was a tendency for a linear decrease in fasting insulin:glucose ratio (0.85, 0.84, 0.42, and 0.59, P = 0.08), which became more noticeable during the postprandial state (3.96, 3.63, 2.63, and 2.73, P = 0.02). Again on d 41, there was a quadratic response on fasting serum glucose concentration (4.32, 4.07, 3.91, and 4.68, P = 0.01) with supplemental B. Results suggest that supplemental boron may impact serum insulin and glucose concentrations by reducing the amount of insulin needed to maintain glucose concentrations. However, higher levels of supplemental boron did result in suppressed growth performance. Thus, additional research is warranted to determine the optimum level of supplemental B.

Two experiments were conducted to investigate effects of feeding graded levels of PBM on performance of weanling pigs and to evaluate feed preference for PBM-based diets relative to spray-dried plasma protein (SDPP)-based diets. A third experiment evaluated PBM in grower diets on performance. In Exp. 1, 120 pigs [body weight (BW) 7.1 ± 0.6 kg] were randomly allotted to 1 of 5 treatments (0, 1, 2, 3, or 5% PBM) and housed 4 pigs/pen for a 28-d growth trial. In Exp. 2, 60 pigs (BW 6.7 ± 1.4 kg) were randomly allotted to 1 of 3 comparisons including: Comparison 1) 0% PBM vs. 2% PBM, Comparison 2) 0% PBM vs. 2% SDPP, and Comparison 3) 2% PBM vs. 2% SDPP and housed 4 pigs/pen for a 28-d preference trial; pigs were provided ad libitum access to feeders; feeder location was switched 3 times/wk. In Exp. 3, 120 pigs (BW 25.9 ± 2.1 kg) were randomly allotted to 1 of 4 treatments (0, 1.25, 2.5 or 5% PBM) and housed 5 pigs/pen for a 41-d growth trial. Increasing PBM from 0 to 5% in Exp. 1 resulted in no differences in ADG (398, 417, 424, 432, and 428 g) or G:F (0.675, 0.686, 0.733, 0.711, and 0.717). Feed preference results (Exp. 2) demonstrated that pigs consumed a higher percentage (76 vs. 24%, P < 0.01) of their total feed intake from the 2% PBM-based diet compared to the 2% SDPP-based diet (Comparison 3). In Exp. 3, increasing PBM for grower pigs resulted in no differences in ADG (1007, 1025, 1002, and 1025 g) or G:F (0.484, 0.472, 0.484, and 0.478). Thus, feeding PBM up to 5% of the diet had no effect on overall performance of nursery or grower pigs, indicating it is an acceptable option as a feed ingredient.

Crossbred pigs (24 barrows and 24 gilts; BW 35.59±0.24 kg) were blocked by body weight, sex, and allotted in a randomized complete block design to 3 dietary treatments: 1) Control [CON], 2) CON+0.25%, and 3) CON+0.50% inclusion of a dacitic tuff breccia (DTB) to evaluate effects on growth performance. Diets were formulated to meet or exceed NRC (2012) requirement estimates and fed for 2 phases (d0-14=PHS_1 and d14-28=PHS_2). Diets were limit fed based on metabolic body weight (3.5 x maintenance ME needs [3.5 × 106 Kcal ME/kg BW0.75]). Pigs were weighed weekly and feed allowance adjusted accordingly. In PHS_1, a tendency for a sex difference, gilt vs. barrow, respectively, for ADG (4.92%; 0.913 vs. 0.870 kg; P=0.10) and G:F (4.14%; 0.528 vs. 0.507; P=0.06) existed. The responses to treatments 1–3, respectively, for ADG (0.877, 0.900, and 0.896 kg; linear P=0.54) and G:F (0.510, 0.522, 0.521; linear P=0.46) were numerically greater. In PHS_2, sex differences, gilt vs. barrow, respectively, for ADG (5.67%; 0.946 vs. 0.895 kg; P=0.05) and G:F (7.98%; 0.460 vs. 0.426; P< 0.01) existed. The numerical responses to treatments 1–3, respectively, for ADG (0.912, 0.944 and 0.905 kg; P=0.41) and G:F (0.439, 0.446, 0.444; linear P=0.70) continued. A tendency for a quadratic response in ADFI (P=0.06) existed because feed allowance increased with increasing weekly BW for treatments 2 and 3. Overall, sex differences, gilt vs. barrow, respectively, for ADG (5.30%; 0.929 vs. 0.882 kg; P< 0.05) and G:F (6.23%; 0.491 vs. 0.462; P< 0.01) occurred. Numerical responses to treatments 1–3, respectively, for ADG (0.895, 0.921 and 0.900 kg, P=0.32) and G:F (0.471, 0.480, 0.479; linear P=0.50) occurred. Additionally, the response to DTB appeared to be higher in barrows.