Xianyin Zeng

Performance and hormone levels of immunocastrated, surgically castrated and intact male pigs fed ad libitum high- and low-energy diets

Immunocastration by immunisation against gonadotrophin-releasing hormone (GnRH), is a good alternative for surgical castration in male pigs, both to prevent boar taint and for animal welfare reasons. In this study we investigated the effect of immunocastration on growth performance of pigs from 25 to 110 kg fed two diets differing in NEf content. Sixty piglets were divided into 20 blocks. Each block consisted of three littermates: a boar, a surgical castrate and an immunocastrate. Two blocks were housed in each pen. The pigs were fed ad libitum and individual feed intake was recorded with an automatic feed registration device. A high-energy and a low-energy diet were fed (9.70 and 8.30 MJ NEf/kg, respectively, based on tabulated values). The immunocastrates were immunised at 10 and 17 weeks of age with 62.5 μg d-Lys6-GnRH tandem dimer peptide conjugated to ovalbumin in Specol adjuvant. Plasma testosterone levels in immunocastrates decreased after the first injection and reached non-detectable levels at 20 weeks of age and thereafter. Immunocastrates had non-detectable fat androstenone levels at slaughter. The results of the concomitant digestibility experiments showed that the estimated NEf contents of the diets were 9.64 and 9.04 MJ/kg, respectively. No differences were observed in digestibility of proximate nutrients among sexes, but digestibility of Ca and P was higher for boars and immunocastrates as compared to surgical castrates (P<0.05). There was no interaction between type of diet and sex for growth performance characteristics except for energy conversion ratio, that approached significance (P=0.095). Feed intake for immunocastrates and surgical castrates was similar, and was higher than for boars on both diets (P<0.001). There was a tendency towards a better growth rate for immunocastrates compared to surgical castrates, irrespective of the energy level of the diet. When compared to boars, growth rate was higher in both immunocastrates and surgical castrates, which was significant only for the low-energy diet (P<0.01). Energy conversion ratio (ECR; expressed as MJ NEf/kg gain) was better for boars than for surgical castrates (P<0.05). For immunocastrates, ECR was in between that of boars and surgical castrates, and was better than for surgical castrates on the low-energy diet (P<0.05). Meat percentage was higher for boars than for surgical castrates and immunocastrates (P<0.05). On the high-energy diet, meat percentage was lower in immunocastrates than in surgical castrates (P<0.05) but on the low-energy diet it was similar. The results of the present study demonstrate that there was a tendency towards a better growth performance for immunocastrates as compared to surgical castrates, especially on the low-energy diet.

Effects of active immunization against GnRH on serum LH, inhibin A, sexual development and growth rate in Chinese female pigs

Surgical castration of young female pigs is common practice in Chinese pig farming today. The purpose of the present study is to investigate anti-GnRH immunization as a practical alternative to surgical castration for female pigs. Thirty-six Chinese female crossbred pigs (Chinese Yanan x Yorkshire) were selected from 12 litters, three pigs from each litter, at the age of 10-13 weeks. One pig from each litter was immunized with 62.5 microg D-Lys6-GnRH-tandem-dimer peptide conjugated to ovalbumin in Specol adjuvant at Week 0 (0 week post-vaccination, wpv), and a booster vaccination was given 8 weeks later (8 wpv). Its intact and castrate littermates (surgically castrated at the time of weaning, i.e. at 6 weeks of age) were administered the vehicle and served as controls. Antibody titers, serum LH and inhibin A were determined at the day of first vaccination, every 4 weeks thereafter and at the day of slaughter (18 wpv). At slaughter, ovaries were inspected for the presence of follicles and corpora lutea, and ovarian and uterine weights were recorded. Ten of twelve immunized pigs responded well to the immunization (immunocastrated animals), while the remaining two pigs responded poorly (nonresponders). Antibody titres in immunocastrated animals steadily increased after immunization, became maximal at 12 wpv and remained high until slaughter. Serum LH levels were reduced (P < 0.05) in immunocastrated pigs as compared to intact controls and surgical castrates. Serum inhibin A levels decreased after vaccination, and equaled surgical castrate levels from 8 wpv until the end of the experiment. Ovarian and uterine weights (1.3 +/- 0.2 and 43.9 +/- 11.4 g, respectively; mean +/- S.E.M.) were significantly lower (P < 0.05) in immunocastrates than in intact controls (9.4 +/- 1.1 and 390.9 +/- 67.2 g, respectively). Antibody titers were significantly lower (P < 0.05) in nonresponders than in immunocastrated pigs from 12 wpv to slaughter. Ovarian and uterine weights were similar in nonresponders and in intact controls. Macroscopically, no follicular structures were found in ovaries of immunocastrated pigs, while large follicles or corpora lutea were observed in the ovaries of both nonresponders and intact controls. Although not significant, immunocastrates had a numerically higher average daily gain than surgical castrates and intact controls (0.74 +/- 0.04 versus 0.66 +/- 0.04 versus 0.66 +/- 0.03 kg per day, respectively; mean +/- S.E.M., P = 0.09). Results obtained in the present study demonstrate that anti-GnRH immunization can be an attractive alternative to surgical castration for Chinese crossbred female pigs. Our results also question the beneficial effect of surgical castration on growth as compared to intact controls.

Astragalus polysaccharides enhance the humoral and cellular immune responses of hepatitis B surface antigen vaccination through inhibiting the expression of transforming growth factor β and the frequency of regulatory T cells

Astragalus polysaccharides (APS), extracted from the root of Astragalus membranaceus, a traditional Chinese medicinal herb, have extensive pharmacological and strong immunomodulatory effects. In this study, the potential adjuvant effect of APS on humoral and cellular immune responses to hepatitis B subunit vaccine was investigated. Coadministration of APS with recombinant hepatitis B surface antigen significantly increased antigen-specific antibody production, T-cell proliferation and CTL (cytotoxic T lymphocyte) activity. Production of interferon-γ (IFN-γ), interleukin-2 (IL-2) and IL-4 in CD4(+) T cells and of IFN-γ in CD8(+) T cells were dramatically increased. Furthermore, expression of the genes PFP, GraB, Fas L and Fas were up-regulated; interestingly, expression of transforming growth factor β (TGF-β) and the frequency of CD4(+)CD25(+)Foxp3(+) regulatory T cells (Treg cells) were down-regulated. Expression of Toll-like receptor 4 (TLR4) was significantly increased by administration of APS. Together, these results suggest that APS is a potent adjuvant for the hepatitis B subunit vaccine and can enhance both humoral and cellular immune responses via activating the TLR4 signaling pathway and inhibit the expression of TGF-β and frequency of Treg cells.

Enhancement of the immune responses to foot-and-mouth disease vaccination in mice by oral administration of a Novel polysaccharide from the roots of Radix Cyathulae officinalis Kuan (RC)

Foot-and-mouth disease (FMD) is a kind of the important animal infectious disease caused by the foot-and-mouth disease virus (FMDV). Thus, the aim of this study was to determine the effects of the polysaccharide from the Radix Cyathulae officinalis Kuan (RCPS) for its adjuvant potential on the FMDV-specific cellular and humoral immune responses in mice. In this study, our findings shows that oral administration of RCPS significantly enhanced the phagocytic capacity of peritoneal macrophage, splenocyte proliferation, the activity of natural killer (NK) cells and cytotoxic T lymphocytes (CTL) and IgG, IgG1, IgG2a, and IgG2b antibody titers. Furthermore, RCPS promoted the level of IL-2, IFN-γ and IL-4 in CD4(+)T cells and level of IFN-γ in CD8(+)T cells. In addition, RCPS enhanced the expression of CD40(+), CD80(+) and CD86(+) on DCs. Importantly, RCPS could up-regulated the mRNA level of MHC I, MHC II, TLR-2, TLR-4. Interestingly, RCPS down-regulated the frequency of CD4(+)CD25(+)Foxp3(+)Treg cells. Taken together, these results demonstrate that RCPS can enhance both cellular and humoral immune responses via up-regulating DCs maturation through TLR2, TLR4 signaling pathway, and suppressing Treg frequency.

Novel polysaccharide from Radix Cyathulae officinalis Kuan can improve immune response to ovalbumin in mice.

This study was designed to investigate the effects of oral administration of the polysaccharide from the Radix Cyathulae officinalis Kuan (RCPS) for its adjuvant potential on the specific cellular and humoral immune responses in mice. In this study, our data demonstrated that oral administration of RCPS significantly enhanced the phagocytic capacity of peritoneal macrophage, splenocyte proliferation, the activity of natural killer (NK) cells and cytotoxic T lymphocytes (CTL) and OVA-specific IgG, IgG1, IgG2a, and IgG2b antibody titers. Furthermore, RCPS promoted the level of interleukin-2(IL-2), IFN-γ and IL-4 in CD4(+)T cells and level of IFN-γ in CD8(+)T cells. In addition, RCPS enhanced the expression of CD40(+), CD80(+) and CD86(+) on the dendritic cells (DCs). Importantly, RCPS down-regulated the frequency of CD4(+)CD25(+)Foxp3(+)Treg cells. Taken together, these results suggested that RCPS could increase both cellular and humoral immune responses via up-regulating DCs maturation, and suppressing Treg frequency.

Characterization and antioxidant activities of the polysaccharides from Radix Cyathulae officinalis Kuan

A water-soluble polysaccharide (PSRC) was extracted and purified from the roots of Radix Cyathulae officinalis Kuan, and its chemical characteristics, monosaccharide composition and antioxidant activities were characterized. The average of molecular weight (Mw) of PSRC was 182 kDa. The majority of monosaccharide components of PSRC was glucose (relative mass 48.8%) with lower levels of mannose, rhamnose, galactose, fructose and arabinose (relative mass of 15.7, 14.3, 10.6, 6.1 and 4.5%, respectively). In vitro assays revealed that RSRC possessed potent scavenging activities against DPPH, hydroxyl and superoxide anion radicals. Oral administration of PSRC significantly enhanced antioxidant enzyme activities (including total superoxide dismutase, copper-zinc superoxide dismutase (Cu,Zn-SOD), manganese superoxide dismutase (Mn-SOD), glutathione peroxidase and catalase (CAT)) and capacities of scavenging superoxide anion and hydroxyl radicals, markedly lowered lipid peroxidation formation of malondialdehyde and significantly up-regulated mRNA expressions of Cu,Zn-SOD, Mn-SOD, CAT, glutathione peroxidase 1, thioredoxin 1 and thioredoxin 2, in a d-galactose-induced aging mouse model. Taken together, these findings demonstrate that PSRC could be used as a novel promising source of natural antioxidants and antiaging drugs.

Active immunization against GnRH reduces the synthesis of GnRH in male rats

We sought to determine the effects of active anti-GnRH immunization on GnRH synthesis in the hypothalamus. Adult male rats (n = 36) were randomly and equally allocated into three groups: Control (no treatment), surgically castrated, or immunized against 50 μg D-Lys6-GnRH-tandem-dimer peptide conjugated to ovalbumin in Specol adjuvant at 12 week of age (with a booster 8 week later). Blood samples (for antibody titers and hormone concentrations) were collected at 2-week intervals until rats were killed (20 week). Compared with intact controls, immunocastration reduced (P < 0.05) serum concentrations of testosterone, LH, and FSH, and GnRH content in the median eminence, reduced the weight of the hypohysis (P < 0.01), and induced testicular atrophy (suppression of spermatogenesis). Furthermore, mRNA expression of GnRH in the hypothalamus, GnRH receptor, LH-β and FSH-β in the pituitary, LH receptor and FSH receptor in the testes, and genes in sex steroid feedback loops (androgen receptor [AR], kisspeptin encoded gene (Kiss-1), and kisspeptin receptor (GPR54) in the hypothalamus were decreased in immunocastrated rats compared with intact controls (P < 0.05). Similarly, surgical castration reduced GnRH in the median eminence as well as mRNA expression of GnRH, AR, Kiss-1, and GPR54 in the hypothalamus (P < 0.05). We concluded that anti-GnRH immunization in adult rats reduced synthesis of hypothalamic GnRH by decreasing androgen-AR-Kisspeptin-GPR54 signaling pathways, and caused dysfunction of the pituitary-testicular axis, thereby suppressing spermatogenesis, resulting in testicular atrophy.

Transcriptome profiling of spleen provides insights into the antiviral mechanism in Schizothorax prenanti after poly (I: C) challenge

ABSTRACT Schizothorax prenanti (S. prenanti) is an important economical cold‐water fish species in southwestern China, but it is susceptible to various pathogens infection. In order to clearly elucidate the antiviral mechanism, in this study, we have analyzed the transcriptome of S. prenanti spleen after challenge with the virus mimic, poly (I:C) (pIC), using next generation sequencing technology (RNA‐seq). A total of 313 differential expressed genes (DEGs) in spleen at 12 h were obtained after pIC treatment, including 268 significantly up‐regulated unigenes (fold change > 2) and 45 significantly down‐regulated unigenes (fold change > 2). Through the immune‐related DEGs (IRDs) screening, 47 IRDs were used to establish heat map, which intuitively showed a significantly difference after pIC treatment. To validate the RNA‐seq data and observe gene expression, the expression levels of 14 IRDs were detected by qPCR after pIC treatment at 0, 4, 8, 12, and 24 h. The results indicated that the qPCR data presented a positive line correlation with RNA‐seq data, and the 14 IRDs were responsive to pIC stimulation except IL‐1&bgr;. Thus, based on the RNA‐seq and qPCR data, we inferred that MDA5‐ and Jak‐mediated signaling pathways may involve in the antiviral signaling transduction, and induce type I IFNs and ISGs to block virus invasion, respectively. Unfortunately, TLR3 and TLR22, as receptors of virus dsRNA, were no significantly expressed in this study. Nonetheless, our study still provides useful mRNA sequences of antiviral immunity for further immunological research, and facilitates improving disease restriction in S. prenanti. HighlightsWe constructed the transcriptome library of Schizothorax prenanti after poly(I:C) treatment.We obtained 313 DEGs after poly(I:C) treatment.We screened 41 immune‐related DEGs after poly(I:C) treatment.We validated the transcriptome data and tested expression level of IRDs by qPCR at the different time points.We predicated the possible mechanism of anti‐virus in Schizothorax prenanti.

Mucosal and systemic immunity in mice after intranasal immunization with recombinant Lactococcus lactis expressing ORF6 of PRRSV

The purpose of the study was to construct mucosal vaccine of a recombinant Lactococcus lactis expressing PRRSV ORF6 gene and evaluate mucosal and systemic immune response against PRRSV in mice after intranasal immunization. The result show that the vaccine can stimulate mice to produce specific IgG in serum and remarkable special s-IgA in lung lavage fluid, at the same time, the contents of cytokines IL-2 and IFN-γ of the experimental group were significant higher than those of the control group (P < 0.01), however, the contents of cytokines IL-4 was not different to the all groups. In summary, the constructed mucosal vaccine can significantly induce mucosal immune, humoral immunity and cellular immunity involved Th1 type cytokines, which will lay a theoretical foundation on immune mechanism and new efficient vaccines for PRRSV.

Biomonitoring chromium III or VI soluble pollution by moss chlorophyll fluorescence

We systematically compared the impacts of four Cr salts (chromic chloride, chromic nitrate, potassium chromate and potassium bichromate) on physiological parameters and chlorophyll fluorescence in indigenous moss Taxiphyllum taxirameum. Among the four Cr salts, K2Cr2O7 treatment resulted in the most significant decrease in photosynthetic efficiency and antioxidant enzymes, increase in reactive oxygen species (ROS), and obvious cell death. Different form the higher plants, although hexavalent Cr(VI) salt treatments resulted in higher accumulation levels of Cr and were more toxic than Cr(III) salts, Cr(III) also induced significant changes in moss physiological parameters and chlorophyll fluorescence. Our results showed that Cr(III) and Cr(VI) could be monitored distinguishably according to the non-photochemical quenching (NPQ) fluorescence of sporadic purple and sporadic lavender images respectively. Then, the valence states and concentrations of Cr contaminations could be evaluated according to the image of maximum efficiency of PSII photochemistry (Fv/Fm) and the quantum yield of PSII electron transport (ΦPSII). Therefore, this study provides new ideas of mosss sensibility to Cr(III) and a new method to monitor Chromium contaminations rapidly and non-invasively in water.