Influence of Particle Size of Enogen Feed High Amylase and Conventional Yellow Dent Corn on Nursery Pig Performance

A total of 360 pigs (DNA 200 × 400; initially 14.5 lb) were used in a 35-d growth trial to evaluate the influence of particle size of Enogen Feed high amylase (Enogen, Syngenta Seeds, LLC, Downers Grove, IL) and conventional yellow dent corn on nursery pig performance. Pigs were randomly assigned to pens (5 pigs per pen) and pens were allotted by weight to 1 of 6 dietary treatments in a randomized complete block design with 12 pens per treatment. Treatments were arranged in a 2 × 3 factorial with main effects of corn source (high amylase or conventional yellow dent) and 3 ground corn particle sizes (300, 600, or 900 microns). All pigs were fed a common pelleted diet for 7 days after weaning, then switched to experimental diets. Overall, from d 0 to 35, there were no differences among corn sources observed for average daily gain (ADG). As particle size of the diet increased, there was a tendency (quadratic, P = 0.074) for ADG to be similar for pigs fed 300and 600-micron ground corn, but ADG decreased for pigs fed corn ground to 900 microns. There was a tendency (P = 0.086) for a corn source × particle size interaction for average daily feed intake (ADFI), with no change in ADFI for pigs fed conventional yellow dent corn, but a quadratic increase then decrease in ADFI for pigs fed high amylase corn. For feed efficiency (F/G), there was also a corn source × particle size interaction (P = 0.027) observed with improved F/G as particle size was reduced for high amylase corn, but not for conventional yellow dent corn. In summary, reducing particle size of high amylase corn improves feed efficiency with no major differences between corn sources for overall daily gain.


Introduction
Enogen Feed high amylase is a corn variety developed by Syngenta Seeds (Downers Grove, IL). Although its primary use has been for the ethanol industry, there is potential application in livestock diets. Recent research has found that feeding high amylase corn improves feed efficiency in finishing cattle. A recent experiment conducted with finishing pigs observed that pigs Swine Day 2020 fed high amylase corn tended to have greater ADG than pigs fed conventional yellow dent corn; however, feed efficiency was not influenced. 5 The greater amylase concentration in Enogen Feed corn is expected to increase starch digestibility compared with yellow dent corn. Grinding corn to fine particle sizes has also been demonstrated to improve starch digestibility, resulting in improved feed efficiency. For nursery pigs, reducing corn particle size is commonly associated with improved feed efficiency; however, some studies have observed reduced feed intake with corn ground finer than 600 microns. 6 The high amylase content in Enogen Feed corn may improve starch digestion similarly to reducing particle size. If this were the case, it is possible that pigs fed coarsely ground Enogen Feed corn might have similar feed efficiency as pigs fed finely ground conventional corn. The ability to grind Enogen Feed corn to a larger particle size, yet maintain optimal F/G, could provide several benefits including reduced grinding costs, improved flowability of diets in bins and feeders, and reduced gastric ulcers and mortality. Therefore, the objective of this study was to evaluate the effects of feeding Enogen Feed high amylase corn vs. conventional yellow dent corn ground to different particle sizes on nursery pig performance.

Procedures
The Kansas State University Institutional Animal Care and Use Committee approved the protocol used in this experiment. The trial was conducted at the Kansas State University Segregated Early Weaning facility in Manhattan, KS. All diets were manufactured at the Kansas State University O.H. Kruse Feed Technology Innovation Center. Enogen Feed corn was sourced from Syngenta Seeds, LLC, Downers Grove, IL. The conventional yellow dent corn was sourced from local producers in northern Kansas. Both Enogen Feed high amylase and conventional yellow dent corn were sampled for chemical analysis (Table 1). During feed manufacturing, approximately 10 pounds of each ground corn treatment were collected. Prior to sending samples for chemical analysis, ground corn was passed through a riffle divider and split down to 200 g. Then 2 samples of each corn source were sent for chemical analysis at Ward Laboratories, Kearney, NE, and the average of the 2 values was used. When formulating the diets, we assumed the same nutritional values between the conventional yellow dent corn and the Enogen Feed high amylase corn.
A total of 360 pigs (DNA 200 × 400; initially 14.5 lb) were used in a 35-d experiment. Pigs were weaned at 21 d of age and fed a common pelleted starter diet for 7 d prior to the start of the experiment. Pigs were randomly allotted to pens and were assigned to 1 of 6 dietary treatments in a randomized complete block design with 5 pigs per pen and 12 pens per treatment. Dietary treatments consisted of 2 different corn sources (Enogen Feed high amylase vs. conventional yellow dent) and 3 corn particle sizes (300, 600, and 900 microns). Treatments were fed for 35 days, split into 2 separate phases ( Table 2). Phase 1 was fed from d 0 to 14 and phase 2 was fed from d 14 to 35. Pigs were weighed and feed disappearance was measured on d 0, 7, 14, 21, 28, and 35. Each pen (4 × 4 ft) contained a 4-hole, dry, self-feeder and a water cup to provide ad libitum access to feed and water.

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Diet samples were collected from the feeder 3 days after the start of each phase, and proximate analysis was conducted on the composite diet (Ward Laboratories, Inc., Kearney, NE). Particle size analysis was conducted on ground corn samples (100 g) with or without the inclusion of a flow agent. When running the particle size analysis, 2 samples of each corn source were used with and without the flow agent. All samples were determined according to ANSI/ASAE S319.2 standard particle size analysis method. 7 Treatments were analyzed as a randomized complete block design for one-way ANOVA using the lmer function from the lme4 package in R (version 3.5.1 (2018-07-02)) with pen considered the experimental unit, body weight as blocking factor, and treatment as fixed effect. The main effects of corn source and particle size, as well as their interactions, were tested. Differences between treatments were considered significant at Ρ ≤ 0.05 and marginally significant at 0.05 < Ρ ≤ 0.10.

Results and Discussion
The chemical analyses of the ground corn sources are described in Table 1. There were no major differences in the chemical analysis of conventional and high amylase corn. Particle size analysis data are in Table 3. Particle size spread was met, but 300-micron ground corn tended to be higher than the intended 300 microns. Chemical analyses of the complete diets are in Table 4. In the complete diet analysis, the Enogen Feed corn had slightly higher calcium values than the conventional corn diets.
From d 0 to 14, pigs fed Enogen Feed corn had increased (P < 0.05) ADG and ADFI compared to those fed conventional yellow dent corn (Tables 5 and 6). There was a corn source by particle size interaction observed for F/G (P = 0.027). There were no changes in F/G of pigs fed conventional yellow dent corn, but a linear improvement in F/G as particle size decreased for those fed Enogen Feed corn.
For d 14 to 35, there was a tendency for pigs fed conventional yellow dent corn to have increased (P = 0.063) ADG compared with those fed Enogen Feed corn. For ADFI, there was a tendency for a corn source × particle size interaction (quadratic, P = 0.071) with no differences in ADFI for pigs fed conventional corn as particle size changed, but an increase then decrease in ADFI as particle size increased in pigs fed Enogen Feed corn. There was a tendency (linear, P = 0.095) for a corn source × particle size interaction observed for F/G. There was no difference in F/G among pigs fed conventional yellow dent corn, but F/G worsened as particle size increased in pigs fed Enogen Feed corn.
Overall, as particle size increased, ADG (P = 0.074) was similar for pigs fed 300 and 600-micron ground corn but decreased for those fed 900-micron corn. As during d 14 to 35, there was a tendency for a corn source × particle size interaction to be observed (quadratic, P = 0.086) for ADFI. There was no difference in pigs fed conventional yellow dent corn, whereas pigs fed Enogen Feed corn had an increase then decrease in ADFI as particle size increased. There was a corn source × particle size interaction (linear, P = 0.027) for overall F/G. There was no difference when pigs were fed conventional yellow dent corn, but in pigs fed Enogen Feed corn, F/G worsened with increasing particle size.
In summary, when grinding corn to finer particle sizes, we observed the expected improvement in F/G of pigs fed Enogen Feed high amylase corn, but not in conventional yellow dent corn. However, there were no overall differences observed for ADG among corn sources.

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Brand names appearing in this publication are for product identification purposes only. No endorsement is intended, nor is criticism implied of similar products not mentioned. Persons using such products assume responsibility for their use in accordance with current label directions of the manufacturer.   Enogen corn will replace conventional yellow dent corn on a lb:lb basis in the diets. Standardized total tract digestible phosphorus. Ground corn samples were collected on the day of feed manufacturing.

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2 Ground corn samples were split down using a riffle device to have 100 g of the corn sample left over. Five g of the flow agent was added to the sample. The ground corn sample was placed into the sieves and processed on the RoTap machine for 15 minutes. After the 15 minutes, the sieves were each individually weighed to see how much sample is left on each sieve.

3
Powdered synthetic amorphous silicon dioxide. 4 Kansas State University particle size analysis template was used to calculate the particle size of each sample.  The experimental diets were fed in 2 phases: d 0 to 14, and d 14 to 35. BW = body weight. ADG = average daily gain. ADFI = average daily feed intake. F/G = feed efficiency. The experimental diets were fed in 2 phases: d 0 to 14, and d 14 to 35. BW = body weight. ADG = average daily gain. ADFI = average daily feed intake. F/G = feed efficiency.