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Pigs inoculated with Porcine Epidemic Diarrhea Virus have decreased growth performance and tissue accretion compared with Controls after 42 days
Porcine epidemic diarrhea virus (PEDV) is an Alphacoronavirus and was first identified in U.S. pigs in April 2013. It is known to affect the small intestine to produce clinical signs of diarrhea and dehydration and can be fatal in piglets. The objective of this study was to determine the longitudinal effect of PEDV infection on nursery pig growth performance and tissue accretion rates. Fifty Choice Genetics gilts and barrows (BW = 9.92 ± 0.49 kg) naïve for PEDV were allotted into 2 treatment groups with equal barrows and gilts distributed among 8 pens per treatment. The treatments were: 1) control (n = 8 pens) and 2) PEDV inoculated (n = 8 pens). At -3 days post inoculation (dpi), a subset of 1 pig per pen was scanned live to determine initial body composition using a dual-energy x-ray (DXA) absorptiometry machine. On 0 dpi, all 25 PEDV pigs were inoculated with 103 TCID50/ml of PEDV via gastric gavage. During 2-14 dpi, 17 pigs per treatment were necropsied to monitor disease progression. On 14 dpi, 8 pigs per treatment remained. Over the 42 d experimental period, PEDV infection and naivety was confirmed via fecal PCR testing. Pen body weights, feed intake, and calculated G:F were recorded on dpi 2, 5, 7 and weekly thereafter. At 42 dpi, the same 8 pigs per treatment were DXA scanned again to determine final body composition and tissue accretion rates were calculated. Gain to reach 127 kg market BW was calculated from average BW at 42 dpi. All pigs were allowed free access to a corn-soybean meal diet and water. Treatment and time effects were determined using pen as the experimental unit. There was no difference (P = 0.344) in start BW between treatments. Overall, compared to the control pigs, PEDV reduced ADFI (0.92 verses 0.70 kg, P = 0.044) and tended to reduce ADG (0.74 verses 0.63 kg, P = 0.056). However, overall G:F was not altered (P = 0.625). Pigs inoculated with PEDV had decreased (P < 0.05) whole body accretion (g/d) for fat, lean, and protein compared to control pigs (24%, 20%, and 21% reductions, respectively). Pigs inoculated with PEDV would need to gain 7% more BW (P= 0.014) than control pigs to reach 127 kg market weight. In summary, we have shown that nursery pig exposure to PEDV has a long term negative impact on pig performance and whole body tissue accretion rates.
Keywords: porcine epidemic diarrhea virus, performance, pigs