Effects of dietary supplement of organic acids induced protective immunity against coccidiosis.

Abstract

This study evaluated effects of three products of dietary organic acids (Acidomix® AFG; Activate® AD and Lacplus) on protective immunity against coccidiosis. Two hundred and eighty 1-day broiler chickens were randomly divided into 8 groups by 5 replications (7 birds per replicate), comprising 2 controls (negative=N; positive=P) and 6 supplemented organic acid groups (1% AFG, 1% DA, 1% Lacplus; 2% AFG, 2% DA and 2% Lacplus). With the exception of N control (uninfected), all 7 groups were orally challenged with 8 × 105 sporulated oocysts of Eimeria tenella at day 12 post-hatch. Samples of blood, spleen and ceca were collected on day 22 and 35 post-hatch. Body weight gain, fecal oocyst shedding, lesion score, mortality rate and pH of the ceca were assessed. ELISA was used to detect Cluster of T cell differentiation (CD4+, CD8+) molecules and reverse transcription polymerase chain reaction (RT-PCR) was employed for detection of pro-inflammatory chemokine (IFNγ-) and cytokines expression (IL-8, IL-15 and IL-17). The result revealed that supplementation of organic acids significantly increased body weight gain, improved feed conversion ratio (FCR), reduced lesion scores and oocyst index (p <0.05) compared to P control (infected non-supplemented). The mortality rate was higher in P control. The pH of ceca was significant (p <0.05) and maximum was observed in P control. Chicks fed 2% DA and 1% Lacplus had greater percentages of CD4 T-cell molecules, but had decreased CD8 T cell molecules, suggesting a protective function of these T-cell subsets in innate immune response against E. tenella infection. The cecal and splenic chemokine and cytokines mRNA expression encoding IFN-γ, IL-8, IL-15 and IL-17 showed higher levels of transcript compared to N and P controls, indicating the organic acid products might have exerted their protective effects by improving their production. It is concluded that the Activate® DA at 2% and Lacplus 1% levels at both 22 and 35-days post-hatch have shown best anticoccidial effects.