The influence of particle size of Enogen Feed corn and conventional yellow dent corn on nursery and finishing pig performance, carcass characteristics and stomach morphology

Enogen Feed corn is a variety developed by Syngenta Seeds (Downers Grove, IL) that has been genetically modified to contain an α-amylase enzyme trait (SYT-EFC). Originally, Enogen feed corn was developed for the ethanol industry due to its reduction in viscosity of the corn mash, thus eliminating the need to add a liquid form of the α-amylase enzyme. However, there is potential application for Enogen Feed corn to be used in livestock diets due to the increase in α-amylase enzyme potential to increase starch digestibility. A more common method of increasing starch digestibility in corn is to finely grind it to reduce particle size. This increases the surface area and allows for greater interaction with digestive enzymes. We hypothesized that pigs fed Enogen feed corn potentially could achieve similar gain:feed ratio (G:F) at larger particle sizes than conventional corn because of the differences in starch digestibility. In Exp. 1, a total of 360 pigs (DNA 200 × 400, Columbus, NE; initially 6.6 ± 0.1 kg BW) were used with 5 pigs per pen and 12 pens per treatment. Treatments were arranged in a 2 × 3 factorial with main effects of corn source (Enogen Feed corn or conventional yellow dent corn) and ground corn particle size (300, 600, or 900 µm). Overall, there was a corn source × particle size interaction (linear, P = 0.027) for G:F. There was no effect due to particle size when pigs were fed conventional yellow dent corn, but in pigs fed Enogen Feed corn, G:F increased with decreasing particle size. Neither corn source nor particle size affected (P > 0.05) overall average daily gain (ADG) or average daily feed intake (ADFI). In Exp. 2, a total of 323 pigs (241 × 600; DNA, Columbus, NE; initially 50.0 ± 1.3 kg) were used with 9 pigs per pen and 6 pens per treatment. Treatments were identical as Exp. 1. Overall, corn source had no effect on finishing pig ADG, ADFI or G:F. For corn particle size, ADG and G:F increased (linear, P < 0.014) and ADFI decreased (P = 0.043) as particle size decreased. For stomach morphology, there was a tendency for a corn source × particle size interaction (P = 0.055) for keratinization score with keratinization increasing linearly (P = 0.001) as particle size of the corn decreased for yellow dent corn with no change in keratinization score as particle size decreased for Enogen Feed corn. In summary, reducing corn particle size improved G:F with no major differences observed between corn sources for overall pig performance.

Different Ground Corn Particle Size in Supplements for Young Bulls Grazing During Intensive System Production

We hypothesized that a decrease in flint corn particle size in the supplements of young bulls during grazing promotes better use of starch in the total gastrointestinal tract, with less starch lost in the feces, thus increasing growth performance. This experiment aimed to evaluate the effects of supplements with different ground corn particle sizes on the growth performance, economic analysis, intake and apparent digestibility of nutrients for beef cattle in Urochloa brizantha cv. Marandu pastures during the rainy-dry transition season. Sixty-four Nelore bulls, with an average age of 16 months and 303.6 ± 18.0 kg of body weight (BW), were distributed in a completely randomized design. The treatments were WG = whole grain (geometric mean particle size, dgw, 6.262 µm); CG = coarse ground grain (dgw, 2.882 µm); MG = medium ground grain (dgw, 1.011 µm); and FG = fine ground grain (dgw, 0.621 µm). The supplements with ground grain or whole grain were similar (P > 0.05) in terms of intake and the digestibility of dry matter (DM), forage, organic matter (OM), crude protein (CP), neutral detergent fiber corrected for ash and protein (NDFap), and total digestible nutrients (TDN). However, the starch digestion in the total tract was higher (P < 0.05) with ground grain than with whole grain. The different geometric mean particle sizes of the grain in the supplements were not sufficient to alter (P > 0.05) the starch digestion in the total tract. The starch fecal concentration decreased with ground grain compared with that for whole grain (P < 0.05). However, no differences in growth performance were observed among the treatments (P > 0.05). Supplementation with CG promoted a slightly greater net revenue (+ 11.51%) and return per ha (+ 12.8%) compared with WG, while MG and FG yielded worse economic results. Therefore, CG showed higher economic performance and efficiency utilization of starch, suggesting it is a better strategy for providing supplements to young grazing bulls.

44 Effects of Decreasing Corn Particle Size on Metabolizable Energy and Proportions of Fecal Volatile Fatty Acids in Gestating Sows

The objective of the first experiment was to determine the effects of corn particle size on the diet apparent total tract digestibility (ATTD) of protein (CP), digestible energy (DE), metabolizable energy (ME) and N-corrected ME (AMEn) in addition to estimating the ME of corn in gestating sows. A total of 27 sows, during the second phase of gestation, were fed a common diet manufactured with corn ground to one of 3 target particle sizes (dgw): 400, 800, or 1200 µm. Titanium dioxide (0.25%) was included in the diet as an indigestible marker for digestibility calculations. Sows were fed experimental diets for 7 days to allow for diet adaptation before a 2-day collection period of urine and fecal samples. Reducing dgw of corn from 1,200 to 400 µm increased (linear, P &lt; 0.01) ATTD CP and GE, DE, ME, AMEn and calculated ME of corn. The objective of the second experiment was to determine the effects of corn particle size on the total concentration and molar proportions of volatile fatty acids (VFA) in the feces of gestating sows. A total of 27 sows were fed treatments similar to Exp. 1 from day 61 to 82 of gestation. On day-82 and 83 of gestation, 2 fecal grab samples were collected for VFA analyses. Sows fed diets with decreasing corn dgw had increased (quadratic, P = 0.021) fecal acetic acid proportions, and decreased propionic (quadratic, P = 0.019) and valeric acid (P = 0.005). In conclusion, for every 100 µm decrease in corn dgw from 1,200 to 400 µm, corn ME value increased by 28.6 kcal/kg. Additionally, decreasing corn particle size led to an increase in the proportion of acetic acid and a decrease in propionic and valeric acid in fecal samples of gestating sows.

133 Influence of Particle Size of Enogen Feed Corn and Conventional Yellow Dent Corn on Nursery and Finishing Pig Performance, Carcass Characteristics and Stomach Morphology

Two studies evaluated the effect of particle size of Enogen® Feed corn (Syngenta Seeds, LLC, Downers Grove, IL) and conventional yellow dent corn on nursery and finishing pig performance, carcass characteristics and stomach morphology. In Exp. 1, 360 nursery pigs (DNA 200×400, Columbus, NE; initially 6.6±0.1 kg BW) were used with 5 pigs per pen and 12 pens per treatment. Treatments were arranged in a 2×3 factorial with main effects of corn source (Enogen Feed corn or conventional yellow dent corn) and ground corn particle size (300, 600, or 900 µm). Overall, there was a corn source×particle size interaction (linear, P = 0.027) for G:F ratio. There was no difference due to particle size when pigs were fed conventional yellow dent corn, but in pigs fed Enogen Feed corn, G:F increased with decreasing particle size. Neither corn source nor particle size affected (P &gt; 0.05) ADG or ADFI. In Exp. 2, 323 finishing pigs (241′600; DNA, Columbus, NE; initially 50.0±1.3 kg) were used with 8 or 9 pigs per pen and 6 pens per treatment. Treatments were arranged identical to Exp. 1. Overall, corn source did not elicit differences in ADG, ADFI or G:F (P &gt; 0.05). For corn particle size, ADG and G:F increased (linear, P ≤ 0.014) and ADFI decreased (P = 0.043) as particle size decreased. For carcass characteristics, there was a tendency (linear, P = 0.093) for increased HCW and increased (linear, P = 0.023) carcass yield as corn particle size decreased. For stomach morphology, there was a tendency for a corn source×particle size interaction (P = 0.055) for keratinization score with keratinization increasing linearly (P = 0.001) as particle size decreased for yellow dent corn with no change in keratinization score as particle size decreased for Enogen Feed corn. In summary, reducing corn particle size improved G:F with no major differences observed between corn sources for overall pig performance.