Biology subjects

Renukaradhya, G.

Publications and source records attributed to Renukaradhya, G..

2 recordsLinked to original sources

bioRxiv2020

Oral immunization of broilers with chitosan nano-encapsulated extracellular and cell wall proteins of necrotic enteritis-induced Clostridium perfringens

Currently, there is no commercial vaccine to control Clostridium perfringens (CP) or necrotic enteritis - a clinically and economically devastating disease. Two chitosan-nanoparticle encapsulated CP (CNP-CP) vaccines using extracellular proteins (ECP) and cell wall proteins (CWP) were synthesized: a CNP-CP ECP + CWP vaccine (SC vaccine) and a CNP-CP ECP + CWP surface-adsorbed CWP vaccine (SCC vaccine). The experiment comprised a complete randomized design of 3 treatments replicated 5 times: SC, SCC and nonimmunized control. Broilers orally gavaged with SC or SCC vaccine were primed and boosted with 70g dose at 3- and 14-days post-hatch (dph). SDS-PAGE analysis revealed bands at 54.7 and 84.7 kDa in the ECP and 17 bands for CWP fraction. There were no differences in body weight gain, feed conversion ratio and mortality rate between treatments. At 17dph, serum of birds in the SC and SCC groups had higher neutralizing antibodies (P<0.01) compared to the control group. At 17dph, there was an increase in bile anti-ECP IgA levels in the SC vaccinated birds and a non-significant increase in SCC vaccinated birds compared to control. At 17dph, bile specific anti-CP CWP IgA levels were greater (P<0.05) in both immunized groups compared to control. At 17 and 21dph, serum anti-ECP and anti-CP CWP IgY levels in SC and SCC birds were comparable to the control. At 21dph, CD4+/CD8+ T-cell ratio in SC and SCC vaccinated groups were elevated (P [≤] 0.01) compared to control. At 17dph, SC and SCC vaccinated birds had a significant reduction (P [≤] 0.001) in -toxin levels in caecal contents compared to control. Caecal -toxin levels remained reduced at 21dph (P < 0.05) in SC birds and numerically reduced in SCC vaccinated birds compared to control. Jejunal CP load in SCC birds was significantly reduced by 1.4 Log10 copy numbers of CP/g compared to control and no differences were observed in liver CP load between immunized and non-immunized birds. SC and SCC immunization did not alter TNF-, IL-10, iNOS, IL-6 or IL-17 mRNA expression. At 17 and 21dph, SC and SCC immunized birds demonstrated greater sera bactericidal activity compared to control. CNP-SC and CNP-SCC immunization induced specific immune response against C. perfringens and reduced CP colonization via oral route of administration.

immunology↗

bioRxiv2020

Chitosan nanoparticle vaccine loaded with crude extracellular proteins of C. perfringens and Salmonella flagella is partially protective against necrotic enteritis in broiler chickens.

Necrotic enteritis (NE) causes significant economic losses and food shortages world-wide. There are currently no licensed commercial vaccines against NE in broilers. Chitosan nanoparticles were formulated with extracellular proteins of C. perfringens surface-tagged with Salmonella flagellar proteins. One-day-old male broiler chicks were completely randomized to 3 treatments: Non-vaccinated non-challenged as negative control, Vaccinated-challenged, and non-vaccinated challenge as positive control. On day of hatch, d7, and d14 post-hatch, vaccinated-challenged birds were orally gavage with 50g vaccine in 0.5ml PBS while positive control birds were gavage with 0.5ml PBS only. Birds in the vaccinated-challenged and positive control groups were orally infected on d14 post-hatch, with 5,000 oocysts/bird of E. maxima, followed by log 8 CFU of a virulent strain of C. perfringens on d19, d20, and d21 post-hatch. From d14 to 21 and d14 to 28 post-hatches, mortality in the vaccinated-challenged group was higher than that in the positive control group, approaching statistical significance (p=0.07). On d21 post-hatch, the mean lesion score of 3 birds/cage in the vaccinated-challenged group was higher than the positive control group, approaching statistical significance (p = 0.05). From d 14 to 28 post-hatch, the feed intake was higher and feed conversion ratio lower in the vaccinated-challenged group compared to the positive control group (p<0.05). On d21 post-hatch, antigen specific recall proliferation in the vaccinated-challenged group was higher than that in the negative and positive control groups (p<0.05). On d21 post-hatch, cecal tonsils CD8+ T lymphocytes expression in the vaccinated-challenged group was similar to the negative control group (p>0.05) but higher than that in the positive control group (p<0.05). Finally, vaccination resulted in an increase in ileal mRNA levels of zonula occluding on d21 post-hatch. In conclusion, there were numerical but not statistically significant decrease in NE lesions and mortality in vaccinated and challenged broilers. Further studies are needed to improve the efficacy of the vaccine and understand the mechanism underlying protection in vaccinated birds.

immunology↗