Publications by authors named "Amy L Petry"

12 Publications

  • Page 1 of 1

Xylanase Supplementation Modulates the Microbiota of the Large Intestine of Pigs Fed Corn-Based Fiber by Means of a Stimbiotic Mechanism of Action.

Front Microbiol 2021 24;12:619970. Epub 2021 Mar 24.

Department of Animal Science, Iowa State University, Ames, IA, United States.

This research tested the hypothesis that xylanase modulates microbial communities within the large intestine of growing pigs fed corn-based fiber through a stimbiotic mechanism(s) of action (MOA). Sixty gilts were blocked by initial body weight, individually housed, and randomly assigned to one of four dietary treatments ( = 15): a low-fiber (LF) control, a high-fiber (HF) control containing 30% corn bran, HF+100 mg/kg xylanase (HF+XY), and HF+50 mg/kg arabinoxylan-oligosaccharide (HF+AX). Pigs were fed dietary treatments for 46 days. On day 46, pigs were euthanized, and mucosa and lumen contents were collected from the cecum and the colon. The V4 region of 16S rRNA genes was sequenced and clustered into 5,889, 4,657, 2,822, and 4,516 operational taxonomic units (OTUs), in the cecal contents and mucosa and colonic contents and mucosa, respectively. In cecal contents, HF+XY increased measures of -diversity compared to LF ( < 0.001). Relative to LF, HF increased the prevalence of 44, 36, 26, and 8, and decreased 19, 9, 21, and 10, of the 200 most abundant OTUs from the cecal contents and mucosa and colonic contents and mucosa, respectively ( < 0.05). Compared to LF, HF increased the abundance of OTUs from the , genera, from the , , and families. In contrast, relative to LF, HF decreased and in the cecal contents, and and in the mucosa. Relative to HF, HF+XY increased 32, 16, 29, and 19 and decreased 27, 11, 15, and 10 of the 200 most abundant OTUs from the cecal contents and mucosa and colonic contents and mucosa, respectively ( < 0.05). The addition of xylanase to HF further increased the abundance of OTUs from the and families across the large intestine. Compared to HF, HF+XY increased the abundance of , , and among all locations ( < 0.05). However, HF+AX did not increase the prevalence of these genera in the large intestine. Supplementing xylanase to HF increased hidden-state predictions of microbial enzymes associated with arabinoxylan degradation, xylose metabolism, and short-chain fatty acid production. These data suggest xylanase elicits a stimbiotic MOA in the large intestine of pigs fed corn-based fiber.
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http://dx.doi.org/10.3389/fmicb.2021.619970DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC8024495PMC
March 2021

Assessing the Statistical Training in Animal Science Graduate Programs in the US: Survey on Statistical Training.

J Anim Sci 2021 Mar 19. Epub 2021 Mar 19.

Department of Animal Science, Iowa State University, Ames, IA, United States of America.

Statistical analysis of data and understanding of experimental design are critical skills needed by Animal Science Graduate Students (ASGS). These skills are even more valuable with the increased development of high-throughput technologies. The objective of this study was to evaluate the perceived statistical training of US ASGS. A survey with 38 questions was shared across US universities, and 416 eligible ASGS from 43 universities participated in this study. The survey included questions on the demographics and overall training, graduate education on statistics, and self-assessment on statistics and career path of ASGS. Several analyses were performed: relationship between perceived received education (PRE; i.e., how ASGS evaluated their graduate education in statistics) and perceived knowledge (PK; i.e., how ASGS evaluated their knowledge in statistics from their education), ranking of statistical topics based on PRE, PK, and confidence in performing statistical analyses (CPSA), cluster analysis of statistical topics for PRE, PK, and CPSA, and factors (demographic, overall training, interest in statistics, and field of study) associated with overall scores for PRE, PK, and CPSA. Students had greater (P < 0.05) PRE than PK for most of the statistical topics included in this study. The moderate to high repeatability of answers within statistical topics, indicate substantial correlations in ASGS answers between PRE and PK. The cluster analysis resulted in distinct groups of "Traditional" and "Non-Traditional" statistical topics. ASGS showed lower (P < 0.05) scores of PRE, PK, and CPSA in "Non-Traditional" compared with "Traditional" statistical methods. Several factors were associated (P < 0.05) with the overall scores of PRE, PK, and CSPA. In general, factors related to greater training and interest in statistics of ASGS were associated with greater overall scores, such as taking more credits in statistics courses, having additional training in statistics outside the classroom, knowing more than one statistics software, and more. This study provided comprehensive information on the perceived level of education, knowledge, and confidence in statistics in ASGS in the US. Although objective measurements of their training in statistics are needed, the current study suggests that ASGS have limited statistical training on topics of major importance for the current and future trends of data-driven research in animal sciences.
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http://dx.doi.org/10.1093/jas/skab086DOI Listing
March 2021

Xylanase modulates the microbiota of ileal mucosa and digesta of pigs fed corn-based arabinoxylans likely through both a stimbiotic and prebiotic mechanism.

PLoS One 2021 27;16(1):e0246144. Epub 2021 Jan 27.

Department of Animal Science, Iowa State University, Ames, Iowa, United States of America.

The experimental objective was to characterize the impact of insoluble corn-based fiber, xylanase, and an arabinoxylan-oligosaccharide on ileal digesta and mucosa microbiome of pigs. Three replicates of 20 gilts were blocked by initial body weight, individually-housed, and assigned to 1 of 4 dietary treatments: a low-fiber control (LF), a 30% corn bran high-fiber control (HF), HF+100 mg/kg xylanase (HF+XY), and HF+50 mg/kg arabinoxylan oligosaccharide (HF+AX). Gilts were fed their respective treatments for 46 days. On day 46, pigs were euthanized and ileal digesta and mucosa were collected. The V4 region of the 16S rRNA was amplified and sequenced, generating a total of 2,413,572 and 1,739,013 high-quality sequences from the digesta and mucosa, respectively. Sequences were classified into 1,538 mucosa and 2,495 digesta operational taxonomic units (OTU). Hidden-state predictions of 25 enzymes were made using Phylogenetic Investigation of Communities by Reconstruction of Unobserved States 2 (PICRUST2). Compared to LF, HF increased Erysipelotrichaceae_UCG-002, and Turicibacter in the digesta, Lachnospiraceae_unclassified in the mucosa, and decreased Actinobacillus in both (Q<0.05). Relative to HF, HF+XY increased 19 and 14 of the 100 most abundant OTUs characterized from digesta and mucosa, respectively (Q<0.05). Notably, HF+XY increased the OTU_23_Faecalibacterium by nearly 6 log2-fold change, compared to HF. Relative to HF, HF+XY increased genera Bifidobacterium, and Lactobacillus, and decreased Streptococcus and Turicibacter in digesta (Q<0.05), and increased Bifidobacterium and decreased Escherichia-Shigella in the mucosa (Q<0.05). Compared to HF, HF+AX increased 5 and 6 of the 100 most abundant OTUs characterized from digesta and mucosa, respectively, (Q<0.05), but HF+AX did not modulate similar taxa as HF+XY. The PICRUST2 predictions revealed HF+XY increased gene-predictions for enzymes associated with arabinoxylan degradation and xylose metabolism in the digesta, and increased enzymes related to short-chain fatty acid production in the mucosa. Collectively, these data suggest xylanase elicits a stimbiotic and prebiotic mechanism.
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http://journals.plos.org/plosone/article?id=10.1371/journal.pone.0246144PLOS
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7840016PMC
January 2021

Can the digestibility of corn distillers dried grains with solubles fed to pigs at two stages of growth be enhanced through management of particle size using a hammermill or a roller mill?

Transl Anim Sci 2020 Jul 12;4(3):txaa171. Epub 2020 Sep 12.

Department of Animal Science, Iowa State University, Ames, IA.

The objective of this study was to determine the impact of reducing the mean particle size (PS) of corn distillers dried grains with solubles (DDGS) with a hammermill (HM) or with a roller mill (RM) on the apparent total tract digestibility (ATTD) of dry matter (DM), gross energy (GE), N, acid hydrolyzed ether extract (AEE), and fiber components in growing and finishing pigs. Twenty-four growing barrows were housed in individual pens and were randomly assigned to a 3 × 2 factorial design ( = 8): three grinding methods [either corn DDGS ground with an HM to a PS of 450 μm; corn DDGS ground with an RM to a PS of 450 μm; and corn DDGS with a PS of 670 μm (not further ground)] and two body weight (BW) periods (growing pigs with an average initial BW of 54.7 ± 0.9 kg, and finishing pigs with an average initial BW of 107.8 ± 1.5 kg BW). Fecal samples were collected for each BW period in the last 3 d of an 11-d feeding period. Titanium dioxide was used as an indigestible marker. Digestibility data were analyzed using the MIXED procedure of SAS. Results showed that finishing pigs tended to have better ATTD of DM than growing pigs ( = 0.09) and had increased ATTD of GE and N than growing pigs ( = 0.03 and < 0.01, respectively). On the other hand, growing pigs had better ATTD of AEE than finishing pigs ( = 0.01). Pig BW period did not affect the ATTD of neutral detergent fiber (NDF), acid detergent fiber (ADF), and hemicellulose. Reducing the mean PS of corn DDGS with either HM or RM (from 670 to 450 µm) improved the ATTD of DM and GE ( < 0.01 and < 0.01), tended to improve the ATTD of N ( = 0.08), and improved the ATTD of AEE ( < 0.01). No effect of reducing PS was observed for the ATTD of NDF, ADF, or hemicellulose. There were no differences between HM and RM in any of the ATTD variables tested. In conclusion, reducing PS of corn DDGS from 670 to 450 μm either with an HM or with an RM improved the digestibility of DM, GE, and AEE and modestly improved the digestibility of N in growing and finishing pigs. However, reducing the PS of corn DDGS did not affect the digestibility of fiber components.
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http://dx.doi.org/10.1093/tas/txaa171DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7751184PMC
July 2020

The effects of enzymatically treated soybean meal on growth performance and intestinal structure, barrier integrity, inflammation, oxidative status, and volatile fatty acid production of nursery pigs.

Transl Anim Sci 2020 Jul 10;4(3):txaa170. Epub 2020 Sep 10.

Department of Animal Science, Iowa State University, Ames.

The objective of this experiment was to determine the impact of diets containing increasing amounts of enzymatically treated soybean meal (ESBM) but decreasing amounts of soybean meal (SBM) on growth performance, intestinal structure, and barrier integrity, inflammation, and oxidative status in weaned pigs. A total of 480 pigs [6.3 1.2 kg body weight (BW)] were blocked by initial BW and pens ( = 12 per treatment) were randomly allotted to one of four dietary treatments. Diets were fed in three phases (days 0-14, 14-28, and 28-35) over a 35-d period. The four dietary treatments consisted of a negative control diet (NC): the NC with 7.0% ESBM (ESBM1), the NC with 14.0% ESBM (ESBM2), and the NC with 21.0% ESBM (ESBM3). Soybean meal was reduced proportionately in each treatment. In phase 2, ESBM inclusion was decreased by 50% (3.5%, 7.0%, and 10.5% ESBM, respectively); phase 3 was a common diet and contained no ESBM. Fecal score was visually ranked weekly using a four-point scale. Intestinal tissue, digesta, and blood samples were collected from 48 pigs (1 per pen) on day 10. Data were analyzed using PROC MIXED of SAS (9.4) with pen as the experimental unit; diet and block were considered fixed effects. Linear and quadratic contrasts were used to determine the effect of increasing ESBM. Overall, ESBM2 and ESBM3 decreased final BW, average daily gain, and average daily feed intake compared to NC and ESBM1 (diet, < 0.05; linear, < 0.05). Overall fecal score (diet, < 0.05) and fecal dry matter ( < 0.05) were improved by feeding ESBM diets compared to NC. Volatile fatty acid (VFA) concentration of acetate, propionate, butyrate, and total VFA in ileal contents increased as ESBM inclusion increased ( < 0.05). Colonic VFA concentration was not impacted ( > 0.10). Total antioxidant capacity was increased by ESBM ( < 0.05). The concentration of mucosal interleukin-4 increased as the inclusion of ESBM increased (linear, < 0.05). Messenger ribonucleic acid abundance of and in ileal tissue was increased by ESBM1 or ESBM2 ( < 0.05). In conclusion, increasing the dietary levels of ESBM over 7% had a negative impact on nursery pig performance, but ESBM positively impacted fecal score. Feeding ESBM improved oxidative status and intestinal barrier integrity while increasing ileal VFA production but had minimal impact on intestinal inflammation or morphology. Further research is needed to determine the optimal inclusion level of ESBM.
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http://dx.doi.org/10.1093/tas/txaa170DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7594344PMC
July 2020

Adverse effects on growth performance and bone development in nursery pigs fed diets marginally deficient in phosphorus with increasing calcium to available phosphorus ratios.

J Anim Sci 2020 Oct;98(10)

Department of Animal Science, Iowa State University, Ames, IA.

The objective of this experiment was to evaluate the growth performance and bone mineral content (BMC) of nursery pigs in response to increasing total calcium (Ca) to available phosphorus (aP) ratios in diets containing phytase (250 FTU/kg; Natuphos E, BASF, Florham Park, NJ). A total of 480 nursery pigs (body weight (BW) = 5.7 ± 0.6 kg) with 10 pigs per pen and 7 pens per treatment (6 pens fed 2.75:1 diet) were allotted to seven treatments consisting of increasing ratios of calcium to available phosphorus (Ca:aP): 1.25, 1.50, 1.75, 2.00, 2.25, 2.50, and 2.75. From day -7 to 0, pigs were fed a common diet. They were then fed the treatment diets during two experimental phases from day 1 to 14 and 15 to 28, respectively. Available P was formulated to 0.33% and 0.27% (approximately 90% of requirement) in dietary phases 1 and 2, respectively. BW, average daily gain (ADG), average daily feed intake (ADFI), and gain-to-feed ratio (G:F) were determined. BMC of the femur was measured on day 28 on one pig per pen using dual x-ray absorptiometry. Data were analyzed as a linear mixed model using PROC MIXED (SAS, 9.3). Orthogonal polynomial contrasts were used to determine the linear and quadratic effects of increasing the Ca:aP. Over the 28-d experimental period, increasing Ca:aP resulted in a linear decrease in ADG (353, 338, 328, 304, 317, 291, and 280 g/d; P < 0.01), ADFI (539, 528, 528, 500, 533, 512, and 489 g/d; P < 0.05), and G:F (0.68, 0.66, 0.64, 0.62, 0.61, 0.59, and 0.58; P < 0.01). Increasing Ca:aP also resulted in decreased BW on days 14 and 28 (P < 0.01). The BMC of the femur decreased with increasing Ca:aP (6.2, 6.3, 5.7, 5.9, 5.5, 5.6, and 5.3 g; P < 0.05). Regression analysis explained the impact of Ca:aP as follows on ADG (ADG [g/d] = 339 - 36x; r2 = 0.81), G:F (G:F = 0.61 - 0.03x; r2 = 0.72), and BMC (BMC [g] = 6.4 - 0.27x; r2 = 0.43), where x is the Ca:aP. In conclusion, all outcomes indicated that any level of calcium above the minimum used in this experiment impaired growth performance and skeletal development. Further research using even lower levels of dietary Ca is warranted.
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http://dx.doi.org/10.1093/jas/skaa325DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7751169PMC
October 2020

Xylanase supplementation in corn-based swine diets: a review with emphasis on potential mechanisms of action.

J Anim Sci 2020 Nov;98(11)

Department of Animal Science, Iowa State University, Ames, IA.

Corn is a common energy source in pig diets globally; when financially warranted, industrial corn coproducts, such as corn distiller's dried grains with solubles (DDGS), are also employed. The energy provided by corn stems largely from starch, with some contribution from protein, fat, and non-starch polysaccharides (NSP). When corn DDGS are used in the diet, it will reduce starch within the diet; increase dietary protein, fat, and NSP levels; and alter the source profile of dietary energy. Arabinoxylans (AXs) comprise the majority of NSP in corn and its coproducts. One strategy to mitigate the antinutritive effects of NSP and improve its contribution to energy is by including carbohydrases within the diet. Xylanase is a carbohydrase that targets the β-1,4-glycosidic bonds of AX, releasing a mixture of smaller polysaccharides, oligosaccharides, and pentoses that could potentially be used by the pig. Xylanase is consistently effective in poultry production and moderately consistent in wheat-based swine diets, but its efficacy in corn-based swine diets is quite variable. Xylanase has been shown to improve the digestibility of various components of swine-based diets, but this seldom translates into an improvement in growth performance. Indeed, a review of xylanase literature conducted herein suggests that xylanase improves the digestibility of dietary fiber at least 50% of the time in pigs fed corn-based diets, but only 33% and 26% of the time was there an increase in average daily gain or feed efficiency, respectively. Intriguingly, there has been an abundance of reports proposing xylanase alters intestinal barrier integrity, inflammatory responses, oxidative status, and other health markers in the pig. Notably, xylanase has shown to reduce mortality in both high and low health commercial herds. These inconsistencies in performance metrics, and unexpected health benefits, warrant a greater understanding of the in vivo mechanism(s) of action (MOA) of xylanase. While the MOA of xylanase has been postulated considerably in the literature and widely studied in in vitro settings, in wheat-based diets, and in poultry, there is a dearth of understanding of the in vivo MOA in pigs fed corn-based diets. The purpose of this review is to explore the role of xylanase in corn-based swine diets, discuss responses observed when supplemented in diets containing corn-based fiber, suggest potential MOA of xylanase, and identify critical research gaps.
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http://dx.doi.org/10.1093/jas/skaa318DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7759750PMC
November 2020

The impact of porcine spray-dried plasma protein and dried egg protein harvested from hyper-immunized hens, provided in the presence or absence of subtherapeutic levels of antibiotics in the feed, on growth and indicators of intestinal function and physiology of nursery pigs.

Transl Anim Sci 2020 Jul 26;4(3):txaa095. Epub 2020 Jun 26.

Department of Animal Science, Iowa State University, Ames, IA.

The objective of this experiment was to compare the effects of spray-dried plasma protein (SDPP) and dried egg protein (DEP), without (AB-) or with (AB+) in-feed antibiotics, on growth performance and markers of intestinal health in nursery pigs raised in commercial conditions. This 42-d experiment utilized 1,230 pigs (4.93 ± 0.04 kg body weight; approximately 15-18 d of age). Pigs were randomly assigned to one of six dietary treatments that were arranged as a 2 × 3 factorial of in-feed antibiotics (AB- vs. AB+) and a specialty protein additive (none [CON], porcine SDPP, or DEP). Diets were fed in four phases with phases 3 and 4 as a common diet across all treatments. Specialty protein additives were fed in phases 1 (0-13 d; 3% SDPP, and 0.20% DEP) and 2 (13-26 d; 2% SDPP, and 0.10% DEP). Antibiotics were fed in phases 1-3 (662 mg chlortetracycline [CTC]/kg, 28 mg carbadox/kg, and 441 mg CTC/kg, respectively). Ileal tissue and blood samples were collected from 48 pigs (8 per treatment) on d 20. Data were analyzed using PROC MIXED of SAS (9.4) with pen as the experimental unit; protein additives, antibiotics, and their interaction were fixed effects and block was a random effect. The pigs experienced naturally occurring health challenges in weeks 2 and 4. In the AB- diets, SDPP and DEP increased average daily gain (ADG; = 0.036) and average daily feed intake (ADFI; = 0.040) compared to CON; in the AB+ diets, neither SDPP nor DEP increased ADG or ADFI compared to CON but SDPP did increase these parameters over DEP. The SDPP and DEP diets decreased the number of individual medical treatments compared to CON ( = 0.001). The AB+ increased ileal mucosal interleukin (IL)-1 receptor antagonist ( = 0.017). Feeding DEP reduced the concentration of mucosal IL-1β compared to CON, but not SDPP ( = 0.022). There was a trend for SDPP and DEP to increase villus height:crypt depth compared to CON ( = 0.066). Neither antibiotics or protein additive affected serum malondialdehyde concentration or ileal mRNA abundance of or , , or ( > 0.10). In conclusion, SDPP and DEP improved growth performance of weaned pigs in the absence of antibiotics but neither improved growth compared to CON when feeding standard antibiotic levels. The specialty proteins had a positive effect on health; specialty proteins and antibiotics were able to modulate some markers of intestinal inflammation and morphology.
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http://dx.doi.org/10.1093/tas/txaa095DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7438620PMC
July 2020

Effects of grinding method and particle size of wheat grain on energy and nutrient digestibility in growing and finishing pigs.

Transl Anim Sci 2020 Apr 16;4(2):txaa062. Epub 2020 May 16.

Department of Animal Science, Iowa State University, Ames, IA.

Feed grains are processed to improve their value in pig diets by exposing kernel contents to enzymatic and microbial action. The objective of this study was to quantify the effect of reducing mean particle size (PS) of wheat grain ground with two different grinding methods (GMs) on the apparent total tract digestibility (ATTD) of nutrients and energy in growing and finishing pigs. Forty-eight barrows were housed in individual pens for 11 d for two periods. Pigs were randomly assigned to a 3 × 2 × 2 factorial experimental design: three target mean PS of wheat grain (300, 500, and 700 µm), two GMs (roller mill and hammermill), and two body weight (BW) periods (growing period; initial BW of 54.9 ± 0.6 kg and finishing period; initial BW of 110.7 ± 1.4 kg). Diets contained one of six hard red wheat grain samples, vitamins, minerals, and titanium dioxide as an indigestible marker. Feed allowance provided 2.5 (for the two lightest pigs in each treatment) or 2.7 (for the remaining six pigs in each treatment) times the estimated daily maintenance energy requirement for each growth stage. Fecal samples were collected for the last 3 d of each period. Data were analyzed as a linear mixed model with pig as a random effect and PS, GM, and BW period and their interactions as fixed effects utilizing the MIXED procedure of SAS. Growing pigs had greater ( < 0.05) ATTD of dry matter (DM), gross energy (GE), N, acid hydrolyzed ether extract (AEE), and neutral detergent fiber (NDF) by lowering mean PS from 700 to 500 μm using either a roller mill or a hammermill. However, digestibility did not increase when PS was reduced from 500 to 300 μm, except for AEE ( < 0.05). Finishing pigs had greater ATTD of DM, GE, N, AEE, and NDF by lowering mean PS with a hammermill from 700 to 500 μm ( < 0.05), but it was greater for 500 μm than for 300 μm ( < 0.05). Using a roller mill reduced the ATTD of DM and NDF by lowering PS from 700 to 300 μm ( < 0.05). The ATTD of GE decreased by lowering PS from 700 to 500 μm with a roller mill ( < 0.05) for finishing pigs. The ATTD of N and AEE for finishing pigs were similar from 700 to 300 μm when ground by a roller mill. These data suggest that the PS that maximized digestibility for a hammermill is 500 μm for both growing and finishing pigs. However, for the roller mill, the PS resulting in the best digestibility were 500 and 700 μm for growing and finishing pigs, respectively.
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http://dx.doi.org/10.1093/tas/txaa062DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7344114PMC
April 2020

Enhancing digestibility of corn fed to pigs at two stages of growth through management of particle size using a hammermill or a roller mill.

Transl Anim Sci 2020 Jan 31;4(1):10-21. Epub 2019 Aug 31.

Department of Animal Science, Iowa State University, Ames, IA.

The experimental objective was to determine the role of mean particle size (PS), grinding method, and body weight (BW) category on nutrient, fiber, and energy digestibility of corn. A total of 48 barrows were housed in individual pens and randomly assigned to one of six dietary treatments for 11 d at two BW categories (55 kg and 110 kg). The six treatments consisted of corn ground at three different targeted mean PSs (300, 500, and 700 µm) using either a roller mill or a hammermill. Fecal samples were collected for the last 3 d of each feeding period. Titanium dioxide was used as an indigestible marker. Digestibility data were analyzed as a linear mixed model using the MIXED procedure of SAS. Finishing pigs had greater apparent total tract digestibility (ATTD) of dry matter (DM), gross energy (GE), and N than growing pigs ( = 0.02, = 0.01, and <0.01, respectively). The ATTD of DM, GE, and N was similar in pigs fed hammermilled corn across all PS treatments. However, in roller-milled corn, they increased as PS was reduced ( < 0.05). The ATTD of acid-hydrolyzed ether extract (AEE) in growing pigs was similar between corn ground at 700 and 500 µm, but it was increased by further reducing PS to 300 µm ( < 0.05). In finishing pigs, the ATTD of AEE increased as mean PS decreased from 700 to 300 µm ( < 0.05). The ATTD of AEE was similar in hammermilled corn at all three PS treatments. On the other hand, the ATTD of AEE was similar in corn ground in a roller mill to 700 and 500 µm, but it increased when PS was reduced to 300 µm ( < 0.05). In conclusion, reducing PS of corn with a roller mill increased digestibility of energy and nutrients, but there was less effect using a hammermill. It is possible that differences in SD, distribution, chemical composition, and the shape of the particles resulting from the two grinding processes help to explain the different response.
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http://dx.doi.org/10.1093/tas/txz146DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7200395PMC
January 2020

Xylanase increased the energetic contribution of fiber and improved the oxidative status, gut barrier integrity, and growth performance of growing pigs fed insoluble corn-based fiber.

J Anim Sci 2020 Jul;98(7)

Department of Animal Science, Iowa State University, Ames, IA.

The experimental objective was to investigate the impact of xylanase on the bioavailability of energy, oxidative status, and gut function of growing pigs fed a diet high in insoluble fiber and given a longer adaptation time than typically reported. Three replicates of 20 gilts with an initial body weight (BW) of 25.43 ± 0.88 kg were blocked by BW, individually housed, and randomly assigned to one of four dietary treatments: a low-fiber control (LF) with 7.5% neutral detergent fiber (NDF), a 30% corn bran without solubles high-fiber control (HF; 21.9% NDF), HF + 100 mg/kg xylanase (HF + XY; Econase XT 25P), and HF + 50 mg/kg arabinoxylan-oligosaccharide (HF + AX). Gilts were fed ad libitum for 36 d across two dietary phases. Pigs and feeders were weighed on days 0, 14, 27, and 36. On day 36, pigs were housed in metabolism crates for a 10-d period, limit fed (80% of average ad libitum intake), and feces and urine were collected the last 72 h to determine the digestible energy (DE) and metabolizable energy (ME). On day 46, serum and ileal and colonic tissue were collected. Data were analyzed as a linear mixed model with block and replication as random effects, and treatment, time, and treatment × time as fixed effects. There was a significant treatment × time interaction for BW, average daily gain (ADG), and gain to feed (G:F; P < 0.001). By design, BW at day 0 did not differ; at day 14, pigs fed LF were 3.5% heavier, and pigs fed HF + XY, when compared with HF, were 4% and 4.2% heavier at days 27 and 36, respectively (P < 0.001). From day 14 to 27 and day 27 to 36, when compared with HF, HF + XY improved ADG by 12.4% and 10.7% and G:F by 13.8% and 8.8%, respectively (P < 0.05). Compared with LF, HF decreased DE and ME by 0.51 and 0.42 Mcal/kg, respectively, but xylanase partially mitigated that effect by increasing DE and ME by 0.15 and 0.12 Mcal/kg, over HF, respectively (P < 0.05). Pigs fed HF + XY had increased total antioxidant capacity in the serum and ileum (P < 0.05) and tended to have less circulating malondialdehyde (P = 0.098). Pigs fed LF had increased ileal villus height, and HF + XY and HF + AX had shallower intestinal crypts (P < 0.001). Pigs fed HF + XY had increased ileal messenger ribonucleic acid abundance of claudin 4 and occludin (P < 0.05). Xylanase, but not AX, improved the growth performance of pigs fed insoluble corn-based fiber. This was likely a result of the observed increase in ME, improved antioxidant capacity, and enhanced gut barrier integrity, but it may require increased adaptation time to elicit this response.
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http://dx.doi.org/10.1093/jas/skaa233DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7392531PMC
July 2020

Xylanase, and the role of digestibility and hindgut fermentation in pigs on energetic differences among high and low energy corn samples1.

J Anim Sci 2019 Oct;97(10):4293-4297

Department of Animal Science, Iowa State University, Ames, IA.

The experimental objective was to evaluate the digestibility and fermentation differences between high and low energy corn samples and their response to xylanase supplementation. Four corn samples, 2 with higher DE content (HE-1 and HE-2; 3.74 and 3.75 Mcal DE/kg DM, respectively) and 2 with a lower DE content (LE-1 and LE-2; 3.63 and 3.56 Mcal DE/kg DM, respectively) were selected based upon a previous digestibility trial. Sixteen individually housed barrows (PIC 359 × C29; initial BW = 34.8 ± 0.23kg) were surgically fitted with an ileal T-cannula and randomly allotted to treatments in an 8 × 4 Youden square design. Dietary treatments were arranged in a 4 × 2 factorial: HE-1, HE-2, LE-1, and LE-2, with and without xylanase supplementation. Diets were formulated using one of the 4 corn samples, casein, vitamins, minerals, and 0.4% chromic oxide as an indigestible marker. Feed intake was established at approximately 3 times the estimated energy required for maintenance (NRC 2012) based upon the average initial BW of the pigs at the start of each collection period, which consisted of 9 d adaptation, 2 d of fecal, and 3 d of ileal collections. Diets, ileal, and fecal samples were analyzed for DM, GE, and total dietary fiber (TDF), to determine apparent total tract (ATTD), hindgut fermentation (HF), apparent ileal digestibility (AID) coefficients. A diet × enzyme interaction was not observed for any of the measured variables (P > 0.10). The HE-1 and HE-2 diets had greater ATTD of GE, and HE-2 diet had greater ATTD of DM (P < 0.001 and P = 0.007, respectively). Xylanase, independent of diet, improved the ATTD of GE and DM (84.8 vs. 83.6% for GE with and without enzyme, respectively, P = 0.008; and 84.2 and 83.0% with and without enzyme, respectively, P = 0.007). The energetic differences among these corn samples appeared to be driven by fermentability in the hindgut. Supplementing xylanase improves digestibility irrespective of the digestibility energy content of corn.
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http://dx.doi.org/10.1093/jas/skz261DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6776269PMC
October 2019