The effects of wheat and crystalline amino acids on nursery and finishing pig growth performance and carcass characteristics

Two experiments were conducted to evaluate the effects of wheat and crystalline amino acids on growth performance of nursery and finishing pigs. In Exp. 1, a total of 192 pigs (PIC, 337 Ã— 1050, initially 26.7 lb BW) were used in a 21-d nursery study. Pigs were allotted to pens by initial BW, and pens were assigned to 1 of 4 dietary treatments in a completely randomized design with 6 pigs per pen and 8 replications per treatment. Treatments included: (1) corn-soybean meal diet, (2) diet 1 with wheat replacing approximately 50% of the corn, (3) wheat replacing 100% of the corn in diet 1 with high amounts of crystalline amino acids, and (4) diet 3 with 5% more SBM and lower crystalline amino acids. Overall, (d 0 to 20), no growth performance differences were found when replacing 50% of corn with wheat (P > 0.75), but tendencies for reduced ADG (linear, P < 0.08) were observed when replacing 100% corn with wheat. Replacing 100% of corn with wheat improved (linear, P < 0.05) caloric efficiency on an ME basis and tended to improve (linear, P < 0.07) caloric efficiency on an NE basis. Adding more soybean meal to all wheat diets tended to improve (P < 0.07) F/G and improved (P < 0.03) caloric efficiency on an NE basis.; Swine Day, Manhattan, KS, November 15, 2012


SWINE DAY 2012
The Effects of Wheat and Crystalline Amino Acids on Nursery and Finishing Pig Growth Performance and Carcass Characteristics1 D. L. Goehring, J. M. DeRouchey, M. D. Tokach, J. L. Nelssen, S. S. Dritz, 2 and R. D. Goodband

Summary
Two experiments were conducted to evaluate the effects of wheat and crystalline amino acids on growth performance of nursery and finishing pigs.In Exp. 1, a total of 192 pigs (PIC, 337 × 1050, initially 26.7 lb BW) were used in a 21-d nursery study.Pigs were allotted to pens by initial BW, and pens were assigned to 1 of 4 dietary treatments in a completely randomized design with 6 pigs per pen and 8 replications per treatment.Treatments included: (1) corn-soybean meal diet, (2) diet 1 with wheat replacing approximately 50% of the corn, (3) wheat replacing 100% of the corn in diet 1 with high amounts of crystalline amino acids, and (4) diet 3 with 5% more SBM and lower crystalline amino acids.Overall, (d 0 to 20), no growth performance differences were found when replacing 50% of corn with wheat (P > 0.75), but tendencies for reduced ADG (linear, P < 0.08) were observed when replacing 100% corn with wheat.Replacing 100% of corn with wheat improved (linear, P < 0.05) caloric efficiency on an ME basis and tended to improve (linear, P < 0.07) caloric efficiency on an NE basis.Adding more soybean meal to all wheat diets tended to improve (P < 0.07) F/G and improved (P < 0.03) caloric efficiency on an NE basis.
In Exp. 2, 288 pigs (PIC 327 × 1050, initially 159.5 lb BW) were used in a 61-d finishing study.Pens of pigs (8 or 7 pigs per pen) were randomly allotted by initial BW to 1 of 4 dietary treatments with 9 replications per treatment.Treatments were fed in two phases and were similar to Exp. 1 with: (1) corn-soybean meal diet, (2) diet 1 with wheat replacing approximately 50% of the corn, (3) wheat replacing 100% of the corn in diet 1 with high amounts of crystalline amino acids, and (4) diet 3 with soybean meal replacing a portion of the crystalline amino acids in diet 3. Overall (d 0 to 61), pigs fed increasing wheat had decreased ADG (linear, P < 0.04) and poorer F/G (linear, P < 0.003), which was primarily due to worsening of each when wheat was fed at 100% compared with 50% of the diet.Replacing corn with wheat tended to improve (linear, P < 0.08) caloric efficiency on an ME basis, but not on an NE basis.Adding more soybean meal to low amount of crystalline amino acids in wheat-based diets had no effect (P > 0.32) on growth performance.

Introduction
With near-record drought conditions in the Midwest causing increases in the price of corn and soybean meal, wheat has potential to become a more common ingredient in swine diets.Wheat is routinely used in diets in other countries.Wheat has higher standardized digestibility of certain amino acids, such as lysine and tryptophan, along with a higher CP and available P; however, due to low oil content, wheat is lower in dietary energy than corn.Wheat has an amino acid profile that allows for higher inclusion rates of crystalline amino acids than in corn-based diets; in fact, crystalline amino acids can be used to replace all of the soybean meal in late finishing diets.Little data with current genetics is available on the effects of these high inclusion rates of crystalline amino acids in wheat-based diets, so these experiments were conducted to determine the effects of replacing corn with wheat and the influence of crystalline amino acid levels in wheat diets on growth performance of nursery and finishing pigs.

Procedures
The Kansas State University Institutional Animal Care and Use Committee approved the protocol used in both experiment.The both studies were conducted at the K-State Swine Teaching and Research Center in Manhattan, KS.Wheat and corn samples used in both experiments were collected and submitted to Ward Laboratories, Inc. (Kearney, NE) for analysis (Table 1).
In Exp. 1, a total of 192 pigs (PIC 327 × 1050, initially 26.7 lb) were used in a 21-d growth trial.Pigs were allotted to pens by initial BW, and pens were assigned to 1 of 4 dietary treatments in a completely randomized design with 6 pigs per pen and 8 replications per treatment.Dietary treatments included: (1) a corn-soybean meal diet, (2) diet 1 with wheat replacing approximately 50% of the corn, (3) wheat replacing 100% of the corn in diet 1 with high levels of crystalline amino acids, and (4) diet 3 with 5% more soybean meal and low crystalline amino acids (Table 2).Crystalline amino acids (lysine, threonine, and methionine) were added to the corn and wheat diets (diets 1 and 3) until another amino acid became limiting.Tryptophan was the fourth limiting amino acid in the corn-based diet, and valine was the fourth limiting amino acid in the wheat-based diet.Then, diet 2 was formed to have similar levels of corn and wheat in both diets.The soybean meal level was increased by 5% in diet 4 to reduce the level of crystalline amino acids.All diets were formulated to a constant standardized ileal digestible (SID) lysine level of 1.26% as required by diet 1 (highest-energy diet).Pig weight and feed disappearance were measured on d 0, 7, 14, and 21 of the trial to determine ADG, ADFI, and F/G.Each pen contained a 4-hole, dry self-feeder and a nipple water to provide ad libitum access to feed and water.Pens had wire-mesh floors and allowed approximately 3 ft 2 /pig.

SWINE DAY 2012
In Exp. 2, a total of 288 pigs (PIC 327 × 1050, initially 159.5 lb BW) were used in a 61-d growth trial.Pens of pigs (7 or 8 pigs per pen) were randomly allotted by initial BW to 1 of 4 dietary treatments with 9 replications per treatment.Dietary treatments were similar to Exp. 1 and included: (1) corn-soybean meal diet, (2) diet 1 with wheat replacing approximately 50% of the corn, (3) wheat replacing 100% of the corn in diet 1 with high amounts of crystalline amino acids, and (4) diet 3 with soybean meal replacing a portion of the crystalline amino acids.Diets were fed in 2 approximately 30-d phases from 150 to 210 lb and 210 to 280 lb (Table 3).All diets were formulated to a constant SID lysine level within phase.Diets were fed via the FeedPro system (Feedlogic Corp, Willmar MN).Pigs and feeders were weighed approximately every 2 wk to calculate ADG, ADFI, and F/G.On d 61, all pigs were individually weighed and tattooed for carcass data collection and transported to Triumph Foods LLC, St. Joseph, MO.Hot carcass weights were measured immediately after evisceration and each carcass was evaluated for percentage yield, backfat, loin depth, and percentage lean.Jowl fat samples were collected and analyzed by Near Infrared Spectroscopy at the plant for IV.Percentage yield was calculated by dividing HCW at the plant by live weight at the farm.
All diets were fed in meal form and prepared at the K-State Animal Science Feed Mill in Manhattan, KS.Feed samples were collected from all feeders during each phase and subsampled into composite samples of each treatment for each phase to measure bulk densities (Tables 2 and 3).
Data were analyzed as a completely randomized design using the PROC MIXED procedure (SAS Institute, Inc., Cary, NC) with pen as the experimental unit.Linear and quadratic contrasts were used to determine the effects of wheat replacing 50 or 100% of the corn (Treatments 1, 2, and 3) and the effects of low vs. high amounts of crystalline amino acids in wheat diets (Treatments 3 vs. 4) and the corn diet compared with the 50% wheat replacement (Treatment 1 vs. 2).Analysis of backfat depth, loin depth, and percentage lean were adjusted to a common carcass weight using HCW as a covariate.Results were considered significant at P ≤ 0.05 and considered a trend at P ≤ 0.10.

Results and Discussion
The analyzed nutrient levels of the wheat and corn used in the experiment were similar to those used in diet formulation (Table 1).Adding increasing amounts of wheat to the diets increased the bulk densities of the diets in both experiments.
In Exp. 1, no differences (P > 0.75) in growth performance were observed for the overall trial (d 0 to 21) when replacing 50% of corn with wheat (Table 4).Tendencies were observed for reduced ADG (linear, P < 0.08) when replacing 100% of corn with wheat, because dietary energy decreased (Tables 3 and 4) with increasing wheat.Replacing 100% of corn with wheat improved (linear, P < 0.05) caloric efficiency on an ME basis and tended to improve (linear, P < 0.07) caloric efficiency on an NE basis.Adding more soybean meal to the wheat-based diets tended to improve (P < 0.07) F/G and improved (P < 0.03) caloric efficiency on an NE basis, indicating that either NE was underestimated in the diet containing extra soybean meal or the extra soybean meal increased the SID amino acids that come from the addition of soybean meal, such as valine or tryptophan, which were beneficial to the nursery pigs.

SWINE DAY 2012
Overall (d 0 to 61) in Exp. 2, increasing levels of wheat decreased (linear, P < 0.04) ADG and worsened (linear, P < 0.003) F/G, which was caused by the decrease in dietary energy when increasing amounts of wheat were included (Table 5).Caloric efficiency tended to be improved (linear, P < 0.08) on an ME basis with increasing amounts of wheat, but not on an NE basis, suggesting that NE was a more appropriate measure of dietary energy.Adding soybean meal to the wheat-based diets to lower the levels of crystalline amino acids had no effect (P > 0.32) on growth performance.A tendency was observed for pigs fed 50% wheat to have increased (P < 0.08) backfat depth compared with pigs fed the corn-based diet.Due to the low oil content in wheat, increasing wheat in the diet reduced (linear, P < 0.001) jowl fat IV.Differing levels of crystalline amino acids had no effect on carcass characteristics.
In summary, wheat can be used to replace 50% of corn in nursery or finishing swine rations without negatively affecting growth performance or carcass characteristics; however, growth rate and feed efficiency were worse when wheat completely replaced corn in the diet.These data also showed that adding maximum levels of crystalline amino acids (lysine, methionine, and threonine until the next limiting amino acid is reached) does not have a major influence on pig performance.Further investigation in nursery diets may be warranted due to the numerically poorer feed efficiency at the highest crystalline amino acid inclusion.Finally, feeding wheat lowers carcass fat IV compared with feeding corn, thus creating a more saturated fat that is more desired by processors.

Table 1 .
Chemical analysis of wheat (as-fed basis) 1 Values in parentheses indicate those used in diet formulation.

Table 3 .
Diet composition in Exp. 2 (as-fed basis) 1 Phase 1 diets were fed from d 0 to d 30; Phase 2 from d 30 to 61. 2 SBM: soybean meal.3Phyzyme600(Danisco,Animal Nutrition, St. Louis, MO), providing 231 phytase units (FTU)/lb, with a release of 0.10% available P.4Diet samples collected from the top of each feeder during each phase.

Table 4 .
Effects of wheat and crystalline amino acids on nursery pig performance 1

Table 5 .
Effects of wheat and crystalline amino acids on finishing pig performance 1