Effects of Taishan Pinus massoniana pollen polysaccharide on immune response of rabbit haemorrhagic disease tissue inactivated vaccine and on production performance of Rex rabbits

Abstract

Varied doses of Taishan Pinus massoniana pollen polysaccharide (TPPPS) and Astragalus polysaccharide (APS) extracted by hot water extraction and ethanol precipiration method were added to the vaccine in order to prepare polysaccharide-rabbit haemorrhagic disease (RHD) tissue inactivated vaccine. The purpose was to study effects of TPPPS on immune response of RHD tissue inactivated vaccine and on production performance of Rex rabbits. Results showed that each index in groups I, II, III and IV was higher than that in group V, especially groups I, II and IV, the difference between which and group V was much more significant (P < 0.05); each index in group I was extremely higher than that in group V (P < 0.01); each index in group I was significantly higher than that in groups II, III (P < 0.05), and generally no significant difference was observed between groups II and III. The overall level in group IV was slightly lower than that in group I. Each index in the polysaccharide groups reached its peak value later than that in the non-polysaccharide groups did. Results suggested that any dose of TPPPS can enhance immunologic function and production performance of rabbits, and the amount of 400 mg per rabbit has the most obvious efficacy. Furthermore, it can extend the immune peak period of RHD tissue inactivated vaccine and the growing peak period of Rex rabbits. TPPPS has generally higher efficiency than APS.

Introduction

As the important biomacromolecule of organism, polysaccharide has a highly complicated structure and species specificity. Research has found that polysaccharide is the critical factor of cell surface signal identification, antigen–antibody reaction and intercellular information transmission and perception. Due to its diversity, abundance and effectiveness, plant polysaccharide has become a hot topic in the current research field [1], [2]. Pine pollen is a kind of omnipotently nutritional pollen, gloriously known as “King of Pollen” [3]. Oral use of pine pollen in China dates back to Tang Dynasty, and pine pollen industry had began to take shape in China by this time. Currently, research of pine pollen is primarily applied to human health care, especially to the improvement of human immunologic function, and has achieved significant effect. Therefore, pine pollen can be adopted in the realm of livestock and poultry farming. The efficacy and physiological reaction of pine pollen is in urgent need of further exploration. The principal pine species in Mount Tai (Chinese name: Taishan) region is Pinus masoniana, therefore Taishan Pinus masoniana pollen is used as the experimental material of this study.

The application of antibiotics on breeding industry of China increases day by day, causing the antibiotic resistance of pathogens to deteriorate. In addition, long existence of immunity inhibition diseases and improper immunization programs have led to immunodeficiency of animals. At present, a variety of plant polysaccharides are certified to have the function of enhancing immunity, whereas the research of Pinus masoniana pollen polysaccharide as immune potentiator on livestock and poultry industry is barely reported both at home and abroad. The development of new immune potentiator made from Pinus masoniana pollen polysaccharide can reduce application amount of antibiotic and to some extent enhance animal immunity, consequently add vitality to livestock industry.

Various polysaccharides have the function of adjusting and enhancing immunity of organism and accelerating growth of animals. In the study by Luo et al. [4], Astragalus polysaccharide can remarkedly improve specific immune response of chickens and elevate immunologic function of Newcastle disease-avian influenza recombinant binary vaccine; in the study by Li et al. [5], a kind of new water-soluble bee pollen polysaccharide from Crataegus pinnatifida Bge can significantly enhance phagocytic rate and phagocytic index of peritoneal macrophages, moreover, it can significantly stimulate proliferation of rat spleen cells; furthermore, as shown by Xue et al. [6], lentinus edodes polysaccharide (LEPS) is able to improve production performance, nutrient digestive rate and antioxidant capacity of piglets. In the previous study, our group proved that immunologic function of mice could be enhanced with direct injection of 200 mg/kg of Taishan Pinus massoniana pollen polysaccharide (TPPPS) [7], whereas it was worthwhile to study the actual effects of the mixture of TPPPS as immune potentiator and vaccine on livestock and poultry. TPPPS, in terms of improving immunologic function and production performance, is the breakthrough point of all the researches in the present study.

In this study, Rex rabbits were adopted as animal models, which were treated with RHD tissue inactivated vaccine containing different doses of polysaccharide under the same condition. By detecting antibody level, lymphocyte ratio, lymphocyte proliferation rate in the blood, average daily intake (ADI) and average daily gain (ADG), effects of TPPPS on immunologic function and production performance of Rex rabbits were analysed.