The impact of organic and inorganic selenium on the immune system of growing broilers submitted to immune stimulation and heat stress

Icm Da Silva,Ra Pereira,Ta Gonçalves,Aml Ribeiro,Cw Canal,L Trevizan,Ll De Almeida,Nrc Hlavac,M Macagnan

doi:10.1590/s1516-635x2010000400005

Abstract

One to 42-d-old (432) female broilers were fed different levels of inorganic selenium (ISe) and organic selenium (OSe), according to the following treatments: (1) 0.3 mg ISe; (2) 0.3 mg ISe + 0.2 mg OSe; (3) 0.5 mg ISe and (4) 0.3 mg OSe/ kg of feed. All birds were vaccinated against infectious bursal disease (IBD) at 19d of age and three birds/replicate (R) were inoculated with sheep red blood cells (SRBC) at 32d. Three other birds/R received Freund’s adjuvant at 37d and avian tuberculin (AT) in the wattle at 47d of age. All birds were submitted to heat stress after 21d. Performance parameters, bursa and spleen weights, lymphocyte bursa depletion, antibody (Ab) production against IBD and SRBC, hematocrit, leukocytes, heterophil/lymphocyte ratio (H/L), and cellular reaction to AT were evaluated. The contrast analysis showed that OSe has improved feed intake (FI) between day 1 and 42 (p<0.10). Birds fed ISe presented worse H/L ratio (p<0.10), but higher Ab titers against IBD (p<0.04) and SRBC (p<0.05) than birds fed OSe, but OSe supplemented birds showed lower lymphocyte depletion scores in the bursa. The higher FI promoted by OSe may be beneficial when rearing broilers in hot weather. The use of ISe induced higher humoral immune response.

Highlights

Nutrient requirements for performance are well established in broilers, but not for efficient immune response
inorganic selenium (ISe) can be used for the biosynthesis of selenoproteins, it is incorporated into body proteins only in the form of selenium is chelated to amino acids (Se-AA) because Met and Se-Met become analogs when sulfur is replaced by Se in the molecule, and are not differentiated by the genetic code that regulates this incorporation
analysis of variance (ANOVA) did not detect any significant effect of selenium levels and sources on performance, but the contrast analysis of mean values revealed that the use of organic selenium (OSe) improved feed intake (FI) between days 1 and 21 (p

Summary

Introduction

Nutrient requirements for performance are well established in broilers, but not for efficient immune response. Selenium is involved in antibody production, and stimulates phagocytosis and chemotaxis of macrophages and neutrophils, depending on the pathogen and on the levels of vitamin E in the diet. It is an essential component of enzyme glutathione peroxidase (GPx), and plays a major role against diseases (Kidd, 2004). When da Silva ICM, Ribeiro AML, Canal CW, Trevizan L, Macagnan M, Gonçalves TA, Hlavac NRC, de Almeida LL, Pereira RA selenium is chelated to amino acids (Se-AA), such as methionine-associated Se (Se-Met), it is better absorbed and more available (Surai, 2000; Edens & Gowdy 2004) than ISe, and is considered an “organic” source (OSe). Se-AA sources are converted into H2Se, but their use in the synthesis of proteins other than body proteins reduces the damage from pro-oxidative effects (Leng et al, 2003)

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Conclusion