Evaluation of Vomitoxin Control Strategies on Nursery Pig Growth Evaluation of Vomitoxin Control Strategies on Nursery Pig Growth Performance and Blood Measures Performance and Blood Measures

Summary A total of 4,318 pigs (337 × 1050, PIC; initially 14.3 ± 0.18 lb) were used in a 35-d growth trial to evaluate mycotoxin control strategies on nursery pig performance and blood measures. Pigs were weaned at approximately 21 d of age and randomly allotted to 1 of 5 dietary treatments. The randomized complete block design was blocking structure including sow farm origin, date of entry into the facility, and average pen BW. A total of 160 pens were used with 80 double-sided 5-hole stainless steel fence line feeders, with feeder serving as the experimental unit. For each feeder, 1 pen contained 27 gilts and 1 pen contained 27 barrows. There were 16 replications per dietary treat-ment. A common phase 1 diet was fed in pelleted form to all pigs for 7 d prior to treatment diets. Experimental treatments were fed in a single phase and included a 1) low deoxynivalenol (DON) diet; 2) high DON diet; 3) high DON + sodium meta-bisulfite (SMB); 4) high DON + Technology1; or 5) high DON + Technology1+. Overall (d 0 to 35), pigs fed the high DON diet had reduced ( P < 0.001) ADG, ADFI, and final BW compared to the pigs fed the low DON diet. Furthermore, pigs fed the high DON+SMB diet had greater ( P < 0.05) ADG, ADFI, and final BW compared to the pigs fed the high DON, high DON+Technology1, or high DON+Tech-nology1+ diets. An improvement ( P < 0.05) in feed efficiency was observed in pigs fed


Introduction
Deoxynivalenol (DON), also known as vomitoxin, is a mycotoxin found in cereal grains and is produced by the Fusarium genus. Pigs are the most susceptible livestock species to DON with exposure to concentrations greater than 1 mg/kg resulting in decreased feed intake and growth. Higher concentrations can result in complete feed refusal and vomiting. 4 The concentration of DON can vary from year to year in cereal grains because of the level of stress the plant experiences during the growing season, such as insect damage, poor soil fertility, and harsh weather conditions. Due to local supply of feed ingredients, swine producers may have no option but to utilize DON-contaminated cereal grains that contain levels greater than 1 mg/kg, resulting in negative effects on growth. There are several strategies of detoxification available to alleviate DON effects in swine diets. Contaminated feed can be treated chemically, physically, or biologically in which probiotics or enzymes are used to limit DON effects during digestion. Although no DON-detoxifying agents are approved by the U.S. Food and Drug Administration, some products can be beneficial. Therefore, the objective of this study was to determine the effect of in-feed technologies in high DON diets on growth performance, serum chemistry, enzymatic activity, and hematological outcomes in nursery pigs.

Animals and diets
The Kansas State University Institutional Animal Care and Use Committee approved the protocol used in this study. This study was conducted at a commercial research facility located in north central Ohio (Bucyrus, OH). A total of 160 pens were used with 80 double-sided 5-hole stainless steel fence line feeders each feeding 2 adjacent pens with feeder serving as the experimental unit. For each feeder, 1 pen contained 27 gilts and 1 pen contained 27 barrows. Each pen was also equipped with a cup waterer to provide ad libitum access to feed and water.
Weaned pigs (approximately 21 d of age) originating from three sow farms were placed into the research facility over an 8-d period. A total of 4,318 pigs (337 × 1050, PIC; initially 14.3 ± 0.18 lb) were used in a 35-d growth trial. At the time of placement in the nursery facility, pens of pigs were weighed and allotted to 1 of 5 dietary treatments in a randomized complete block design with blocking structure including sow farm origin, date of entry into the facility, and average pen BW. There were 16 replicates (feeders) per dietary treatment.
A common phase 1 diet was fed in pelleted form to all pigs for 7 d prior to treatment diets. Experimental treatments included a low DON diet, a high DON diet; high DON + sodium metabisulfite (SMB); high DON + Technology1; or high DON + Technology1+. Sodium metabisulfite was included in the diet at 10 lb/ton (Table 1). Technology1 (Innovad Global; Essen, Belgium) was included in diets at 6 lb/ton. Tech-nology1+ (Innovad Global; Essen, Belgium) with SMB included was added to diets at a total product inclusion rate of 6 lb/ton. Treatment diets were fed in one phase and were manufactured at the Hord Elevator (Bucyrus, OH). All diets met the NRC 5 requirement estimates. Feed samples were collected from at least 6 feeders per treatment per feed delivery to the research facility. Samples were subsampled and sent for mycotoxin analysis (Activation Laboratories, Tonawanda, NY).
Feed additions to each individual feeder were made and recorded by an electronic feeding system (Dry Exact; Big Dutchman, Inc., Holland, MI). Pens of pigs were weighed and feed disappearance was calculated every 7 d until the conclusion of the trial to calculate ADG, ADFI, and feed efficiency. Feed disappearance was measured by using a volumetric regression equation which estimates the quantity of feed remaining in the feeder subtracted by the quantity of feed added to the feeder.
Pigs that died or were removed during this study due to sickness or injury were recorded. Any pig that was removed from a test pen was considered a removal and placed into a hospital pen where they remained for the duration of the study. Mortality is defined as a pig that died while in a test pen or a pig that died from a hospital pen. Total removals and mortality accounted for removals and mortality.

Blood sampling
One average weight gilt of each experimental unit (80 total) was bled on d 28 to 35, depending on the date of entry into the facility, for immunological, hematological, and biochemical analysis. Blood was collected in tubes without anticoagulant to obtain serum for chemistry and oxidative stress parameters. Blood was allowed to clot before centrifuging for 15 min at 1,500 g to collect serum, and samples were stored at -112°F (-80°C) until analyzed. Serum samples were sent to the Iowa State University Veterinary Diagnostic Laboratory (Ames, IA) for antibody titers of porcine circovirus type 2 (PCV2) using an ELISA kit. Serum samples were also sent to the Kansas State Veterinary Diagnostic Laboratory (Manhattan, KS) for serum chemistry analysis. Thiobarbituric acid reactive substances (TBARS) were evaluated on serum samples at Kansas State University swine laboratory (Manhattan, KS). The TBARS assay was a modification of the methods of Yagi (1998)  Blood samples were also collected in tubes containing an anticoagulant, EDTA to obtain whole blood for hematological analysis. Whole blood samples were sent to the Kansas State Veterinary Diagnostic Laboratory (Manhattan, KS) for complete blood counting (CBC). Due to the long transport time from Ohio to Kansas, approximately half of the samples were clotted before analysis could be conducted. Leukocyte differentials (Kansas State University Veterinary Diagnostic Laboratory, KS) were performed on the samples that clotted during transportation. Dried blood spots (DBS) were prepared by placing one drop of blood from each whole blood sample onto a protein saver card. The DBS cards were sent to University of Ghent, Belgium, for mycotoxin analysis. Complete quantification (ng/mL) or mean peak area ± standard deviation of 36 mycotoxins and their phase 1and phase 2 metabolites was simultaneously performed after extraction and liquid chromatography with tandem mass spectrometry (LC-MS/ MS) analysis of spotted blood volume (approximately 60 uL) on Whatman 903 protein saver cards. 8

Statistical analysis
Data were analyzed as a randomized complete block design for one-way ANOVA using the GLIMMIX procedure of SAS OnDemand for Academics (SAS Institute, Inc., Cary, NC). Feeder (2 pens of pigs) was considered the experimental unit. Initial pen average BW, sow farm origin, and date of entry into the facility were used as blocking factors. Treatment was used as the fixed effect. For TBARS assay, microplate was used as a random effect. A log 2 transformation was used for PCV2 titers. Results were considered significant with P ≤ 0.05 and were considered marginally significant with P ≤ 0.10.

Results and Discussion
Analysis of DON in the low DON corn was 1.1 ppm at the beginning of the study and 3.8 ppm at the end of the study. Analysis of DON in the high DON corn was 4.4 ppm at the beginning of the study and 4.0 ppm at the end of the study. Concentrations of DON, zearalenone, and fumonisin were detected in treatment diets throughout the study (Table 2).

Growth performance
From d 0 to 14, pigs fed the high DON diet had decreased (P < 0.05) ADG, ADFI, and BW compared to the pigs fed the low DON diet (Table 3). Pigs fed the high DON+SMB diet had greater (P < 0.05) ADG, ADFI, and BW compared to the pigs fed the high DON, high DON+Technology1, or high DON+Technology1+ diets. Furthermore, pigs fed high DON+Technology1+ had heavier (P < 0.05) BW compared to high DON and similar to pigs fed low DON. An improvement (P < 0.05) in feed efficiency was observed in pigs fed high DON+SMB compared to the low DON, high DON, or high DON+Technology1, with pigs fed high DON+Tech-nology1+ diets intermediate.
From d 14 to 21, pigs fed the high DON diet had reduced (P < 0.05) ADG, ADFI, and BW compared to the pigs fed the low DON diet. Pigs fed high DON+SMB had greater (P < 0.05) BW, ADG, and ADFI compared to the pigs fed the high DON, high DON+Technology1, or high DON+Technology1+ diets. Similar findings were observed from d 21 to 28 with a statistical difference (P = 0.047) in feed efficiency across treatments, but using a Tukey multiple comparison adjustment no significant pairwise differences were observed.
From d 28 to 35, pigs fed the high DON diet had similar ADG, ADFI, and F/G compared to the low DON diet. Pigs fed the high DON+Technology1 had poorer (P < 0.05) ADG, ADFI, and F/G compared to all other treatments. An improvement (P < 0.05) in feed efficiency was observed for the pigs fed high DON or high DON+Technology1+ compared to pigs fed high DON+Technolgy1 with low DON and high DON+SMB intermediate.
From d 0 to 35, pigs fed the high DON diet had decreased (P < 0.05) ADG, ADFI, and final BW compared to the pigs fed the low DON diet. Pigs fed the high DON+SMB diet had greater (P < 0.05) ADG, ADFI, and final BW compared to the pigs fed the high DON, high DON+Technology1, or high DON+Technology1+ diets. Additionally, pigs fed high DON+Technology1+ had increased (P < 0.05) ADG and final BW compared to the high DON and similar to the pigs fed low DON diets. An improvement (P < 0.05) in feed efficiency was observed in pigs fed high DON+SMB or high DON+Technology1+ diets compared to the low DON or high DON+Technology1 diets, with high DON diets intermediate.
No differences (P > 0.10) were observed for removals (Table 3). Pigs fed high DON+SMB or high DON+Technology1 had lower (P < 0.05) mortality compared to pigs fed low DON diets with high DON or high DON+Technology1+ intermediate. The same results were observed for total removals and mortality.
For economic analysis, pigs fed high DON+SMB diets had the greatest (P < 0.05) feed cost, revenue, and IOFC compared to all other treatments. Feed cost per lb of gain was greatest (P < 0.05) when pigs were fed high DON+Technology1 diets. Similar findings were observed when using high or low ingredient prices for economic analysis.
For the blood measurements, no differences (P > 0.10) were observed across treatments for complete blood count or leukocyte differential analyses; however, pigs fed high DON+Technology1+ had numerically the lowest neutrophil:lymphocyte ratio (Table 4). In the serum chemistry analysis, pigs fed high DON+Technology1 diet had a greater (P < 0.05) chloride concentration compared to high DON pigs with low DON, high DON+SMB, or high DON+Technology1+ intermediate (Table 5). Additionally, pigs fed high DON had a greater (P < 0.05) bicarbonate concentration compared to pigs fed high DON+SMB with low DON, high DON+Technology1, or high DON+Technology1+ intermediate. There was a statistical difference (P = 0.038) in anion gap across treatments, but using a Tukey multiple comparison adjustment no significant pairwise differences were observed.
For the dried blood spot card, pigs fed high DON or high DON+Technology1 had increased (P < 0.05) DON concentrations compared to low DON with high DON+SMB and high DON+Technology1+ intermediate (Table 6). A marginally significant difference (P = 0.095) in beta-zearalenol positive samples was observed with the pigs fed high DON diets having the greatest percentage compared to all other treatments. While not statistically different, the presence and concentrations of fumonisin B1 and B2, beauvericin, and beta-zearalenol were numerically reduced in pigs fed high DON+Technology1+ with values similar to pigs fed low DON diets; suggesting that additional research is warranted to further elucidate potential benefits from including this product in diets containing mycotoxin-contaminated grains.
In summary, results of this experiment indicate that pigs fed high DON diets had reduced performance compared to pigs fed low DON diets. These results also indicate that SMB was a suitable mycotoxin control strategy for nursery pig diets with DON concentrations evaluated in this study. The metabolic changes observed in our study by pigs fed high DON+Technology1+ warrant further investigation, especially in diets contaminated with mixed mycotoxins.
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.    Technology 1+ (Innovad Global; Essen, Belgium) with SMB included with a total product inclusion of 6 lb/ton. 6 Pigs that were removed from a test pen were considered a removal and placed in a hospital pen where they remained alive for the duration of the study.     A total of 4,318 pigs (initially 14.3 ± 0.18 lb) were used with 54 pigs per replicate and 16 replications per treatment. A common starter pellet diet was used for approximately 7 d containing no mycotoxin control products and manufactured with low deoxynivalenol (DON) corn, and treatment diets were formulated in a single phase for the remainder of the study. Dried blood spots (DBS) were prepared by placing one drop of blood from each whole blood sample onto a protein saver card. The DBS cards were sent to the University of Ghent, Belgium, for mycotoxin analysis. Complete quantification (ng/mL) or mean peak area ± standard deviation of 36 mycotoxins and their phase 1 and phase 2 metabolites was simultaneously performed after extraction and liquid chromatography with tandem mass spectrometry (LC-MS/MS) analysis of spotted blood volume (approximately 60 uL) on Whatman 903 protein saver cards. Concentration is reported by treatment for all samples with a sample result > limit of quantification (LOQ). Positive samples are reported as percentage of samples within treatment with result > limit of detection (LOD). Samples with a result of trace detection of metabolite (LOD < sample result < LOQ) are reported as count by treatment. One sample had trace levels of fumonisin B3 from the high DON treatment. Technology 1 (Innovad Global; Essen, Belgium) inclusion at 6 lb/ton. 5 Technology 1+ (Innovad Global; Essen, Belgium) with SMB included with a total product inclusion of 6 lb/ton. a,b,c,d Means within a row with different superscripts differ (P < 0.05) using a Tukey multiple comparison adjustment.