Dietary plant extracts improve immune responses and growth efficiency of pigs experimentally infected with porcine reproductive and respiratory syndrome virus1

Abstract

A study was conducted to evaluate the effects of 3 different plant extracts on growth performance and immune responses of weaned pigs experimentally infected with porcine reproductive and respiratory syndrome virus (PRRSV). A total of 64 weaned pigs (7.8 ± 0.3 kg BW), free of PRRSV, were randomly allotted to 1 of 8 treatments in a 2 × 4 factorial arrangement with a randomized complete block design. Pigs were blocked by initial BW. Sex and ancestry were equalized across treatments. The first factor was with or without PRRSV challenge (intranasal dose; 10(5) 50% tissue culture infective dose). The second factor was represented by 4 diets: a nursery basal diet (CON), 10 mg/kg capsicum oleoresin (CAP), garlic botanical (GAR), or turmeric oleoresin (TUR). Pigs were housed in disease containment chambers for 28 d [14 d before and after the inoculation (d 0)]. Blood was collected on d 0, 7, and 14 to measure the total and differential white blood cells (WBC), and serum was collected to measure viral load by quantitative PCR, PRRSV antibody titer, tumor necrosis factor-α (TNF-α), IL-1β, C-reactive protein (CRP), and haptoglobin (Hp) by ELISA. In the unchallenged group, all piglets were PRRSV negative during the overall period postinoculation. All data were analyzed using PROC MIXED of SAS. The PRRSV challenge decreased (P < 0.01) ADG, ADFI, and G:F from d 0 to 14. Feeding TUR improved G:F of the PRRSV-infected pigs from d 0 to 14. The numbers of WBC and neutrophils were decreased (P < 0.05) by PRRSV on d 7 but increased (P < 0.05) by PRRSV on d 14, indicating the PRRSV-infected pigs undergo a stage of weak immune responses. Feeding GAR increased (P < 0.05) B cells and CD8+ T cells of PRRSV-infected pigs compared with the CON. Furthermore, the PRRSV challenge increased (P < 0.05) serum viral load, TNF-α, and IL-1β on d 7 and serum viral load, CRP, and Hp on d 14, but feeding plant extracts to PRRSV-infected pigs reversed (P < 0.05) this increase. Infection with PRRSV increased (P < 0.05) rectal temperature of pigs on d 7, 9, and 11, but PRRSV-infected pigs fed plant extracts had lower rectal temperature (P < 0.05) than pigs fed the CON, indicating feeding plant extracts delayed the fever caused by PRRSV infection. In conclusion, results indicate that supplementation with plant extracts reduces the adverse effects of PRRSV by improving the immune responses of pigs, and the 3 plant extracts tested here show different effects. Supplementation with TUR improved feed efficiency of pigs challenged with PRRSV.

Effects of rumen-protected Capsicum oleoresin on immune responses in dairy cows intravenously challenged with lipopolysaccharide

“…Liu et al (2013a) supplemented Capsicum oleoresin (10 mg/kg DM) in pigs challenged with E. coli and observed no effect on rectal temperature and a decrease in white blood cells. In another experiment from the same group, Liu et al (2013b) reported that Capsicum supplementation (10 mg/kg DM) decreased rectal temperature but did not affect white blood cells in pigs challenged with porcine reproductive and respiratory syndrome virus. These studies are consistent with results in the current study.…”

β-glucan from mulberry leaves and curcuma can improve growth performance and nutrient digestibility in early weaned pigs

“…Because of recent limitation of antibiotics addition, new feed additives such as herbs, spices, prebiotics, and probiotics have received increased attention as possible alternatives to antibiotics (Windisch et al 2008;Chu et al 2011;Huang et al 2012;Zhang et al 2012;Liu et al 2013;Wang et al 2013;Zhang & Kim 2013;Zhao et al 2013b;Cho & Kim 2014;Park & Kim 2014;Zhang & Kim 2014).…”

Standardized Plant Extract Alleviates the Negative Effects of FMD Vaccination on Animal Performance

“…This better DM digestibility might be due to the reduction in pathogenic microbes and the increase in beneficial gut microbes in the intestine induced by the capsicum oleoresin. The plant extracts tested reduced diarrhea and inflammation caused by E. coli infection, which may be beneficial to pig health [25]. However, Maneewan et al [26] demonstrated that the inclusion of graded level of turmeric improved the digestibility of crude fat, crude protein, and crude fiber, but had no effect on DM and energy digestibility in weaning pigs.…”