Glycerol Monolaurate to Ameliorate Efficacy of Inactivated Pseudorabies Vaccine

Qinghai Ren; Xiaobo Wang; Qingqing Gao; Gaiqin Wang; Xiaochen Chen; Chunxue Liu; Song Gao; Yubao Li

doi:10.3389/fvets.2022.891157

Glycerol Monolaurate to Ameliorate Efficacy of Inactivated Pseudorabies Vaccine

Front Vet Sci. 2022 Sep 15:9:891157. doi: 10.3389/fvets.2022.891157. eCollection 2022.

Authors

Qinghai Ren^{1

2

3

4}, Xiaobo Wang^{2

3

4}, Qingqing Gao^{2

3

4}, Gaiqin Wang⁵, Xiaochen Chen⁵, Chunxue Liu⁵, Song Gao^{2

3

4}, Yubao Li¹

Affiliations

¹ College of Agronomy and Agricultural Engineering, Liaocheng University, Liaocheng, China.
² Key Laboratory of Avian Bioproducts Development, Ministry of Agriculture, Yangzhou, China.
³ Jiangsu Co-innovation Center for Prevention and Control of Important Animal Infectious Diseases and Zoonoses, Yangzhou, China.
⁴ Institutes of Agricultural Science and Technology Development, College of Veterinary Medicine, Yangzhou University, Yangzhou, China.
⁵ Anyou Biotechnology Group Co., Ltd., Taicang, China.

Abstract

The present study is aimed to evaluate the effect of glycerol monolaurate (GML) on the growth performance and immune enhancement of pseudorabies virus (PRV)-inactivated vaccine in the early-weaned piglets. One hundred and twenty-five 28-day-old weaned piglets were randomly assigned to a control group (CON, no vaccine and no challenge), challenge control group (C-CON), inactivated PRV vaccine group (IPV), IPV + 500 mg/kg GML group (L-GML), and IPV + 1,000 mg/kg GML group (H-GML) during the entire 28-day experimental period. All the data analyses were performed by one-way analysis of variance (ANOVA) and multiple comparisons. Our results showed that the final weight, average daily gain (ADG), and average daily feed intake (ADFI) of H-GML were the highest in each group, and F/G of H-GML was increased but there was no significant difference with CON (p > 0.05). Levels of PRV glycoprotein B (gB) antibody and immunoglobulin in serum of L-GML and H-GML were higher than those of IPV, but only gB antibody levels and immunoglobulin G (IgG) in H-GML were significantly increased (p < 0.05). Compared with IPV, the contents of tumor necrosis factor-α (TNF-α), interleukin-6 (IL-6), and interleukin-1β (IL-1β) in serum of L-GML (TNF-α and IL-1β: p > 0.05, IL-6: p < 0.05, respectively) and H-GML (p < 0.01, both) were all decreased, and the content of interleukin-10 (IL-10) in H-GML was increased (p > 0.05). Furthermore, reverse transcription-polymerase chain reaction (RT-PCR) experiments proved that L-GML and H-GML were both superior to IPV in inhibiting the expression of TNF-α (p < 0.01), IL-6 (p > 0.05), and IL-1β (p < 0.01) mRNAs and promoting the expression of IL-10 mRNA (L-GML: p > 0.05, H-GML: p < 0.05, respectively) in the superficial inguinal lymph nodes. Histopathological examination found mild congestion in the lung and inguinal lymph nodes of IPV, while the tissues (brain, lung, and inguinal lymph nodes) of L-GML and H-GML were the same as CON with no obvious lesions. The above results indicate that GML may improve the growth performance of weaned piglets and enhance the immunity of PRV-inactivated vaccine by increasing the levels of PRV gB antibody and immunoglobulin and regulating cytokine levels.

Keywords: glycerol monolaurate; immune enhancement; inactivated vaccine; pseudorabies virus; weaned piglets.