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An evaluation of porcine epidemic diarrheavirus survival in individual feed ingredients in the presence or absence of a liquid antimicrobial

View Article: PubMed Central - PubMed

ABSTRACT

Background: Contaminated complete feed and porcine plasma are risk factors forPEDV introduction to farms and a liquid antimicrobial has been proven useful forreducing risk. This study provides information on the survivability of PEDVacross common swine feed ingredients in the presence or absence of the liquidantimicrobial.

Results: Eighteen ingredients commonly included in commercial swine dietswere selected, including 3 grain sources (corn, soybean meal (SBM), drieddistillers grains with solubles (DDGS)), 5 porcine by-products (spray-driedplasma, purified plasma, intestinal mucosa, meat and bone meal and red bloodcells (RBCs)), 3 vitamin/trace mineral (VTM) mixes (sow, nursery, finishing), 2fat sources (choice white grease and soy oil), 3 synthetic amino acids (lysineHCL, D/L methionine, threonine), as well as limestone and dry choline chloride.Complete feed and stock PEDV served as controls. Thirty grams of each ingredientwere inoculated with 2 mL PEDV. A matched set of samples were treated with theformaldehyde-based liquid antimicrobial SalCURB® (LA). All samples (n = 320) were stored outdoors under winter timeambient conditions for 30 days. Samples were submitted on 1, 7, 14 and 30 dayspost-inoculation (DPI) and tested by PCR and virus isolation (VI). AllVI-negative samples were tested by swine bioassay. Viable PEDV was detected byVI or swine bioassay at 1, 7, 14 and 30 DPI from SBM, DDGS, meat & bonemeal, RBCs, lysine HCL, D/L methionine, choice white grease, choline chloride,complete feed and stock virus control and at 7 DPI in limestone and at 14 DPI inthreonine. Supplementary testing of complete feed and SBM indicated viable virusout to 45 and 180 DPI, respectively. All other samples were negative by VI andbioassay. In contrast, treatment with LA inactivated PEDV across all ingredientson 1 DPI and induced RNA reduction over time.

Conclusions: Under the conditions of this study, PEDV viability in feed wasinfluenced by ingredient with extended survival in SBM. Furthermore, LAtreatment rendered virus inactive, independent of ingredient type.

No MeSH data available.


Change in mean PEDV Ct levels of non-treated ingredientsthroughout the sampling period. This figure depicts the changeover time in Ct values in the non-treated (saline placebo)ingredient samples collected during the study period. Allingredients were determined to be PCR-negative prior toinoculation. After PEDV inoculation, Ct levels ranged acrossingredients from a low of 16.26 (SBM) to a high of 35.98 (soyoil). Note the consistent trend of Ct across the ingredientpanel, indicating that PEDV quantity in all ingredients isremaining relatively constant over time, as expected in theabsence of intervention
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Fig1: Change in mean PEDV Ct levels of non-treated ingredientsthroughout the sampling period. This figure depicts the changeover time in Ct values in the non-treated (saline placebo)ingredient samples collected during the study period. Allingredients were determined to be PCR-negative prior toinoculation. After PEDV inoculation, Ct levels ranged acrossingredients from a low of 16.26 (SBM) to a high of 35.98 (soyoil). Note the consistent trend of Ct across the ingredientpanel, indicating that PEDV quantity in all ingredients isremaining relatively constant over time, as expected in theabsence of intervention

Mentions: All feed ingredient samples were PCR negative on day 0 of thestudy. Successful PEDV inoculation was confirmed, as all day 1 samples werePCR-positive. Results of PCR testing of LA treated and non-treated ingredientson 1 and 30 DPI are summarized in Table 1 and trends in Ct levels of treated and non-treatedingredients over the 30 day period are displayed in Figs. 1 and 2.The mean Ct of treated samples was 23.74 (SD = 5.9) on 1 DPI and 37.23(SD = 2.5) on 30 DPI. Only SBM (Ct = 28.22) and meat and bone meal (Ct = 33.21)remained PCR positive at 30 days PI, all other treated samples had Ct values of≥38 indicating PEDV RNA was not detected, including the treated positive controlcomplete feed samples. When analyzed by t-test, the difference in mean Ct of treated ingredients wassignificant at p < 0.0001. In contrast,mean Ct values across non-treated ingredients on day 1 averaged 23.46 (SD = 5.5)and 20.78 (SD = 3.8) on day 30. When analyzed by t-test, this difference was not significant at p = 0.1143. Finally, when analyzed by t-test, the mean Ct of 30 DPI treated samples(Ct = 37.23) was significantly different (p < 0.0001) than the mean Ct of 30 DPI non-treated samples(20.78).Table 1


An evaluation of porcine epidemic diarrheavirus survival in individual feed ingredients in the presence or absence of a liquid antimicrobial
Change in mean PEDV Ct levels of non-treated ingredientsthroughout the sampling period. This figure depicts the changeover time in Ct values in the non-treated (saline placebo)ingredient samples collected during the study period. Allingredients were determined to be PCR-negative prior toinoculation. After PEDV inoculation, Ct levels ranged acrossingredients from a low of 16.26 (SBM) to a high of 35.98 (soyoil). Note the consistent trend of Ct across the ingredientpanel, indicating that PEDV quantity in all ingredients isremaining relatively constant over time, as expected in theabsence of intervention
© Copyright Policy - open-access
Related In: Results  -  Collection

License 1 - License 2
Show All Figures
getmorefigures.php?uid=PMC5382523&req=5

Fig1: Change in mean PEDV Ct levels of non-treated ingredientsthroughout the sampling period. This figure depicts the changeover time in Ct values in the non-treated (saline placebo)ingredient samples collected during the study period. Allingredients were determined to be PCR-negative prior toinoculation. After PEDV inoculation, Ct levels ranged acrossingredients from a low of 16.26 (SBM) to a high of 35.98 (soyoil). Note the consistent trend of Ct across the ingredientpanel, indicating that PEDV quantity in all ingredients isremaining relatively constant over time, as expected in theabsence of intervention
Mentions: All feed ingredient samples were PCR negative on day 0 of thestudy. Successful PEDV inoculation was confirmed, as all day 1 samples werePCR-positive. Results of PCR testing of LA treated and non-treated ingredientson 1 and 30 DPI are summarized in Table 1 and trends in Ct levels of treated and non-treatedingredients over the 30 day period are displayed in Figs. 1 and 2.The mean Ct of treated samples was 23.74 (SD = 5.9) on 1 DPI and 37.23(SD = 2.5) on 30 DPI. Only SBM (Ct = 28.22) and meat and bone meal (Ct = 33.21)remained PCR positive at 30 days PI, all other treated samples had Ct values of≥38 indicating PEDV RNA was not detected, including the treated positive controlcomplete feed samples. When analyzed by t-test, the difference in mean Ct of treated ingredients wassignificant at p < 0.0001. In contrast,mean Ct values across non-treated ingredients on day 1 averaged 23.46 (SD = 5.5)and 20.78 (SD = 3.8) on day 30. When analyzed by t-test, this difference was not significant at p = 0.1143. Finally, when analyzed by t-test, the mean Ct of 30 DPI treated samples(Ct = 37.23) was significantly different (p < 0.0001) than the mean Ct of 30 DPI non-treated samples(20.78).Table 1

View Article: PubMed Central - PubMed

ABSTRACT

Background: Contaminated complete feed and porcine plasma are risk factors forPEDV introduction to farms and a liquid antimicrobial has been proven useful forreducing risk. This study provides information on the survivability of PEDVacross common swine feed ingredients in the presence or absence of the liquidantimicrobial.

Results: Eighteen ingredients commonly included in commercial swine dietswere selected, including 3 grain sources (corn, soybean meal (SBM), drieddistillers grains with solubles (DDGS)), 5 porcine by-products (spray-driedplasma, purified plasma, intestinal mucosa, meat and bone meal and red bloodcells (RBCs)), 3 vitamin/trace mineral (VTM) mixes (sow, nursery, finishing), 2fat sources (choice white grease and soy oil), 3 synthetic amino acids (lysineHCL, D/L methionine, threonine), as well as limestone and dry choline chloride.Complete feed and stock PEDV served as controls. Thirty grams of each ingredientwere inoculated with 2&nbsp;mL PEDV. A matched set of samples were treated with theformaldehyde-based liquid antimicrobial SalCURB&reg; (LA). All samples (n&thinsp;=&thinsp;320) were stored outdoors under winter timeambient conditions for 30&nbsp;days. Samples were submitted on 1, 7, 14 and 30&nbsp;dayspost-inoculation (DPI) and tested by PCR and virus isolation (VI). AllVI-negative samples were tested by swine bioassay. Viable PEDV was detected byVI or swine bioassay at 1, 7, 14 and 30 DPI from SBM, DDGS, meat &amp; bonemeal, RBCs, lysine HCL, D/L methionine, choice white grease, choline chloride,complete feed and stock virus control and at 7 DPI in limestone and at 14 DPI inthreonine. Supplementary testing of complete feed and SBM indicated viable virusout to 45 and 180 DPI, respectively. All other samples were negative by VI andbioassay. In contrast, treatment with LA inactivated PEDV across all ingredientson 1 DPI and induced RNA reduction over time.

Conclusions: Under the conditions of this study, PEDV viability in feed wasinfluenced by ingredient with extended survival in SBM. Furthermore, LAtreatment rendered virus inactive, independent of ingredient type.

No MeSH data available.