Evaluation of High Amylase Corn on Growth Performance and Evaluation of High Amylase Corn on Growth Performance and Carcass Characteristics of Finishing Pigs Carcass Characteristics of Finishing Pigs

Summary A total of 288 pigs (Line 600 × 241, DNA, Columbus, NE; initially 91.5 lb) were used in an 82-d trial to determine if replacing conventional yellow dent corn with high amylase corn (Enogen ® , Syngenta Seeds, LLC) in diets with or without distillers dried grains with solubles (DDGS) influences growth performance and carcass characteristics. Pens contained 8 pigs with an equal number of barrows and gilts. There were 9 pens per treatment with pens assigned randomly to treatments balancing for initial body weight. Diets were arranged in a 2 × 2 factorial with two corn sources (conventional or high amylase) and two levels of DDGS (0 or 25%). Experimental diets were fed in meal form in 3 phases: d 0 to 29, d 29 to 47, and d 47 to 82. Pigs were weighed approximately every 2 weeks and at the start of each phase. On d 82, pigs were transported to a commercial packing plant for processing and carcass data collection. Overall, average daily gain (ADG) was marginally greater ( P < 0.089) for pigs fed high amylase corn than conventional corn with no evidence for difference in feed intake, feed efficiency (F/G), hot carcass weight (HCW), or other carcass traits. Added DDGS resulted in decreased ( P < 0.026) overall ADG and poorer ( P < 0.047) F/G compared to pigs fed no DDGS. Pigs fed DDGS had marginally lower ( P < 0.086) HCW, less ( P < 0.045) backfat, and marginally greater ( P < 0.054)


Introduction
Starch from cereal grains is the greatest source of energy in swine diets, thus increasing digestibility of starch can potentially have a positive impact on growth performance.Initially developed for ethanol production, Enogen ® Feed Corn (Syngenta Seeds, LLC) is a corn hybrid with increased expression of heat-stable alpha-amylase.Feeding Enogen ® corn to both growing and finishing beef cattle resulted in improved feed efficiency; however, there is limited research on the effect of feeding this hybrid to swine and poultry. 4,5Production of ethanol has also resulted in availability of low-cost byproducts, such as DDGS, which are commonly added to swine diets in an effort to reduce feed costs.Research on adding DDGS in swine diets, and its impact on growth performance and carcass characteristics, has yielded varying results. 6,7,8Due to DDGS being included in swine diets at the expense of corn, it is important to assess whether any interaction exists between corn variety and DDGS inclusion rate.Therefore, the objective of this trial was to determine whether replacing conventional corn with Enogen ® high amylase corn in diets with or without DDGS influences growth performance and carcass characteristics of finishing pigs.

Procedures
All procedures used in this study were approved by the Kansas State University Institutional Animal Care and Use Committee.This study was conducted at the Kansas State University Swine Teaching and Research Center, Manhattan, KS, from September to December 2018.
Pigs were housed in a fully enclosed, environmentally regulated barn containing 36 pens with slatted concrete floors.Pens were equipped with a two-space single sided feeder (Farmweld, Teutopolis, IL) and a cup waterer, and pigs were allowed access to feed and water ad libitum.The floor space allowance per pig was maintained at 7.83 ft 2 .An automated feeding system (FeedPro; Feedlogic Corp., Wilmar, MN) was used to deliver and record feed to each pen.Corn samples were collected at time of feed manufacturing, and feed samples were collected approximately two days after each feed delivery.Samples were stored at -20°C until sent for analysis.Pooled samples for each phase were sent to a commercial labora-4 Johnson, M. A., T. J. Spore, S. P. Montgomery, C. S Weibert, J. S. Garzon, W. R Hollenbeck, R. N. Wahl, E. D. Watson, and D. Blasi. 2018. Syngenta Enhanced Feed Corn (Enogen)  tory (Ward Laboratories, Inc., Kearney, NE) for analysis of dry matter (DM), starch, crude protein (CP), crude fiber (CF), fat, calcium, and phosphorus (Tables 1 and 2).
A total of 288 pigs (DNA 600 × 241;initial BW 91.5 ± 4.3 lb) were enrolled in an 82-d trial.There were 9 pens per treatment and 8 pigs per pen with an equal number of barrows and gilts per pen.Pens were randomly assigned to dietary treatments and balanced based on pen weight at the start of the study.Dietary treatments (Table 3) were arranged in a 2 × 2 factorial with two corn sources (conventional or high amylase) and two levels of DDGS (0 or 25%).The experimental diets were fed in 3 phases: d 0 to 29, d 29 to 47, and d 47 to 82.Diets were fed in meal form and both corn sources were ground to a similar particle size for the experiment (Table 3).
Pen and feeder weights were obtained approximately every 2 weeks and at the end of each phase change in order to calculate ADG, average daily feed intake (ADFI), and F/G (Tables 4 and 5).During the study, 6 pigs died or were removed due to health related issues.On d 82, 282 pigs were individually weighed, ear tagged with a radio frequency identification (RFID) tag, and tattooed for individual carcass data measurements.Pigs were transported to a commercial packing plant (Triumph Foods, St. Joseph, MO) for processing and collection of hot carcass weight (HCW), loin depth, backfat depth, and percentage lean.Carcass yield was calculated as HCW divided by individual live animal weight.Iodine values (IV) were measured on 2 barrows randomly selected from each pen (Tables 6 and 7).
Data were analyzed using the PROC GLIMMIX procedure of SAS (v.9.4, SAS Institute, Inc., Cary, NC) with pen serving as the experimental unit.The main effects of corn source, DDGS, and their interactions were tested using orthogonal contrasts.For analyses of loin depth, backfat depth, and percentage lean, HCW was used as a covariate.Results were considered significant at P ≤ 0.05 and marginally significant at P ≤ 0.10.

Results
Minor interactions were observed for ADG during phases 1 and 3.During phase 1, pigs fed the diet containing high amylase corn without DDGS had greater (P < 0.019) ADG and greater (P < 0.035) ADFI than pigs fed the high amylase with 25% DDGS; whereas there were no differences between the conventional corn treatments.During phase 3, ADG was greater (P < 0.041) for pigs fed the high amylase corn containing 25% DDGS compared to the 25% DDGS conventional corn diet, with no differences between corn sources if the diet did not contain DDGS.There were no interactions (P > 0.05) between corn source and DDGS for overall performance or any of the carcass measurements.Pigs fed high amylase corn had a marginally greater (P < 0.089) ADG during phase 3 and for the overall experiment than pigs fed conventional corn.There was no evidence for differences in ADFI, F/G, HCW, and other carcass characteristics between corn sources.There was a marginally significant interaction for iodine value where adding DDGS to the conventional corn diets increased iodine value slightly more than when DDGS were added to the high amylase corn diets.
The results of this trial suggest that the high amylase corn hybrid tended to improve overall ADG; however, feed efficiency and carcass characteristics were unchanged between corn sources.Consistent with previous research, the addition of DDGS decreased ADG and increased IV.The marginally lower backfat, greater loin depth, and percentage lean for pigs fed 25% DDGS may be attributed to their lower HCW and overall decreased ADG.Further research should be conducted to understand if addition of high amylase corn to swine diets could be beneficial in other phases of growth or whether heat treatment of diets, such as pelleting, may influence the response to high amylase corn.

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4
The experimental diets were fed in 3 phases: d 0 to 29, d 29 to 47, and d 47 to 82. 5 ADG = average daily gain.ADFI = average daily feed intake.F/G = feed efficiency.
Containing an Alpha Amylase Expression Trait Improves Feed Efficiency in Growing Calf Diets.Kansas Agricultural Experiment Station Research Reports: Vol.4: Iss. 1. 5 Horton, L.M. 2018.Processing methods for high-amylase corn: impact on ruminal digestion and feedlot cattle performance.MS Thesis.Kansas State University.Manhattan, KS.

Table 5 .
Main effects of corn variety and dried distillers grains with solubles (DDGS) on growth performance of finishing pigs 1 2 Yellow dent corn.3 High amylase corn (Enogen ® , Syngenta Seeds, LLC). 4 The experimental diets were fed in 3 phases: d 0 to 29, d 29 to 47, and d 47 to 82. 5 ADG = average daily gain.ADFI = average daily feed intake.F/G = feed efficiency.

Table 6 .
Effects of corn variety and dried distillers grains with solubles (DDGS) inclusion on carcass characteristics of finishing pigs 1 On d 82, 282 pigs were individually weighed, ear tagged with a radio frequency identification (RFID) tag, and tattooed individual carcass data measurements.Pigs were transported to a commercial packing plant (Triumph Foods, St. Joseph, MO) for processing and collection of carcass data.High amylase corn (Enogen ® , Syngenta Seeds, LLC).
2 Yellow dent corn.3 5 HCW used as a covariate in statistical analysis.

Table 7 .
Effects of corn variety and dried distillers grains with solubles (DDGS) inclusion on carcass characteristics of finishing pigs 1On d 82, 282 pigs were individually weighed, ear tagged with a radio frequency identification (RFID) tag, and tattooed for individual carcass data measurements.Pigs were transported to a commercial packing plant(Triumph Foods, St. Joseph, MO)for processing and collection of carcass data.