Effect of dietary supplementation of mannanoligosaccharides on hepatic gene expressions and humoral and cellular immune responses in aflatoxin-contaminated broiler chicks.

The present study was conducted to investigate the effects of dietary supplementation of mannanoligosaccharides (MOS) on expression of hepatic immunological genes and immune responses in aflatoxin-contaminated broiler chicks. A total of 336 seven-day-old Ross broiler chicks were randomly allotted to 7 experimental treatments with 4 replicates and 12 birds per replicate. Experimental treatments consisted of 2 aflatoxin levels (0.5 and 2 ppm) and 3 supplemental MOS levels (0, 1 and 2 g/kg) as a 2 × 3 factorial arrangement in comparison with a control group (unchallenged group). The chicks were challenged with a mix of aflatoxins during 7-28 d of age. Results showed that aflatoxin challenge resulted in the lower antibody titers against infectious bronchitis (IBV) and bursal (IBD) diseases viruses. In addition, aflatoxin-contaminated birds had a lower (P < 0.0001) lymphocyte percentage and a decline in (P < 0.01) interleukin-2 (IL-2) mRNA abundance. Likewise, heterophil proportion, heterophil to lymphocyte ratio and gene expressions of hepatic interleukin-6 (IL-6) and C reactive protein (CRP) were raised (P < 0.001) by increasing dietary aflatoxin level. Dietary inclusion of MOS increased (P < 0.05) antibody titers against IBV, IBD and Newcastle disease virus. Lymphocyte proportion and hepatic IL-2 gene expression were greater (P < 0.0001) in MOS-supplemented birds. Furthermore, supplemental MOS decreased hepatic IL-6 and CRP abundances. Additionally, inclusion of 2 g/kg MOS resulted in the upregulation (P < 0.01) of hepatic IL-2 gene expression in birds contaminated with 0.5 ppm aflatoxin. The present results indicate that supplemental MOS could improve cellular immunity via the upregulation of hepatic IL-2 gene expression in birds challenged with aflatoxins.

Seroprevalence of hepatitis A in Iranian adolescents: is it time to introduce a vaccine?

Universal vaccination of children for hepatitis A virus (HAV) has emerged as a cost-effective strategy to prevent this infection in regions with high incidence of symptomatic disease. Age-specific seroprevalence surveys are practical and reliable methods to estimate the rate of susceptibility in populations, and to help the implementation of vaccination policies. We surveyed the age-specific HAV seroprevalence in a nationally representative sample of Iranian adolescent students aged 10-18 years. Serum samples (n = 2494) were tested by enzyme immunoassay for total anti-HAV antibody. The overall rate of HAV seropositivity was 64% [95% confidence interval (CI), 62-66), which increased sharply from 14·8% (95% CI 7-23) at age 10 years to 72·9% (95% CI 68-78) at age 13 years, without a significant increase up to age 18 years. No significant difference in HAV seroprevalence was observed between males and females (63% vs. 65·1%), or urban and rural areas (63·4% vs. 65·2%); the seropositivity rate was similar in four different socioeconomic regions of Iran. We conclude that the seroconversion rate of HAV is high in Iranian adolescents and therefore mass vaccination of children may be necessary and should be considered by national health authorities.