The effect of porcine reproductive and respiratory syndrome virus and porcine epidemic diarrhea virus challenge on growing pigs I: Growth performance and digestibility1

Abstract

Porcine reproductive and respiratory syndrome (PRRS) and porcine epidemic diarrhea (PED) are two diseases costly to the U.S. swine industry. The objective of this study was to determine the impact of PRRS virus and PED virus, alone or in combination, on growth performance, feed efficiency, and digestibility in grower pigs. Forty-two gilts (16 ± 0.98 kg BW) naïve for PRRS and PED were selected and allocated to 1 of 4 treatments. Treatments included 1) a control, 2) PRRS virus infected, 3) PED virus infected, and 4) PRRS+PED coinfection (PRP). Pigs in treatments 2 and 4 were inoculated with a live field strain of PRRS virus via intramuscular and intranasal routes at 0 d after inoculation (dpi). Treatments 3 and 4 were orally inoculated with a cloned PED virus at 15 dpi. Infection with PRRS virus was confirmed by quantitative PCR and seroconversion. Infection with PED virus was confirmed with PCR. Control pigs remained PRRS and PED virus negative throughout the study. All pigs were offered, ad libitum, a standard diet with free access to water. During the test period, PRRS reduced ADG and ADFI by 30 and 26%, respectively ( < 0.05), compared with control pigs, whereas PRP decreased ADG, ADFI, and G:F by 45, 30, and 23%, respectively ( < 0.05). Additional reductions in ADG and G:F were detected in PRP pigs compared with singular PED or PRRS treatments (33 and 16%, respectively). The impact of PED, alone or in combination, on performance (15-21 dpi) reduced ADG (0.66 vs. 0.35 vs. 0.20 kg/d; < 0.01), ADFI (1.22 vs. 0.88 vs. 0.67 kg/d; = 0.003), and G:F (0.54 vs. 0.39 vs. 0.31; = 0.001) compared with control pigs. Compared with control pigs, PRRS infection did not reduce apparent total tract digestibility (ATTD) of nutrients and energy. However, PED infection, alone or in combination, decreased ATTD of DM and energy by 8 and 12%, respectively ( < 0.05). Compared with control pigs, PRP reduced N and OM ATTD by 13 and 3%, respectively ( < 0.05). No significant differences in apparent ileal digestibility (AID) were detected between virus challenges. However, Lys AID tended to be reduced in both PED treatments compared with the control (10 and 12%; = 0.095). Altogether, PRRS reduced growth but did not alter digestibility. Pigs challenged with PED and, to a greater extent, the coinfection of PED and PRRS viruses had reduced ADG, ADFI, G:F, and ATTD of nutrients and energy.

Swine enteric coronavirus disease: A review of 4 years with porcine epidemic diarrhoea virus and porcine deltacoronavirus in the United States and Canada

“…In growing pigs approximately 7 weeks of age, Schweer, Schwartz et al. () compared the growth performance characteristics of pigs infected with PEDV alone, pigs infected with a combination of PEDV and porcine reproductive and respiratory syndrome virus (PRRSV), and uninfected controls. Infection with PEDV reduced the ADG of gilts compared to the controls by almost half (0.66 kg compared to 0.35 kg) over the 7 days of post‐infection.…”

“…Infection with PEDV reduced the ADG of gilts compared to the controls by almost half (0.66 kg compared to 0.35 kg) over the 7 days of post‐infection. Interestingly, infection of pigs with PRRSV and PEDV in combination resulted in a greater reduction in ADG than with either singular infection, indicating the importance of co‐infections in the pathogenesis of both viruses (Schweer, Schwartz et al., ).…”

Impact of viral disease hypophagia on pig jejunal function and integrity

“…Reduced nutrient intake under health compromised conditions, known as disease anorexia or hypophagia, is an aspect of sickness behavior conserved across nearly all animal species [13][14][15]. In pigs, disease anorexia is a major reason for the loss in lean tissue growth observed during both viral [16][17][18] and bacterial [19][20][21] challenges. One viral disease characterized by a marked reduction in feed intake is Porcine Reproductive and Respiratory Syndrome, which remains one of the most problematic swine diseases worldwide [22].…”

“…One viral disease characterized by a marked reduction in feed intake is Porcine Reproductive and Respiratory Syndrome, which remains one of the most problematic swine diseases worldwide [22]. The causative pathogenic agent for this disease is the double-stranded RNA Porcine Reproductive and Respiratory Syndrome Virus (PRRSV), which induces respiratory disease in growing pigs accompanied by a reduction in both feed intake and growth performance [18,23] that can even result in weight stasis or loss [16].…”

<i>GBP6</i>: differential expression in pulmonary alveolar macrophages under PRRSV infection and association with blood parameters of its missense mutation

“…Porcine respiratory and reproductive syndrome virus (PRRSV) affects all stages of pig production . In grower pigs, it limits the work of general defence mechanisms and predisposes the animals to common diseases such as pneumonia (Goyal, 1993, Schweer et al, 2016. PRRSV has a preference in pulmonary alveolar macrophages (PAM), where it replicates extensively (Bautista et al, 1993, Lee et al, 2010.…”