Hypothyroidism and Antibody Prodction in Immature Male Chickens

Abstract

This study was conducted to determine if hypothyroidism has an effect on humoral immunity in immature male chickens. Two week old Single Comb White Leghorn male chicks were used as experimental animals. Two experiments were conducted using different methods to induce hypothyroidism. In Experiment 1, birds were surgically thyroidectomized (Tx group) and in Experiment 2, hypothyroidism was induced by supplementing the feed throughout the experiment with 0.1% propylthiouracil (PTU group). Antibody production against sheep red blood cells (SRBC) (thymus-dependent antigen) and Brucella abortus (BA) (thymus-independent antigen) was tested at 4 weeks of age. Serum concentrations of T4 and T3 were measured in birds from each treatment group at 5 and 9 weeks of age. Body weights were recorded and birds were then autopsied and thyroid gland weights were measured. Hypothyroidism was successfully induced in both Tx and PTU birds, as reflected by significant reduction in body weights in both groups, enlargement of thyroid glands in PTU birds and absence of thyroid glands in Tx birds. Though T4 and T3 were reduced in sera of treated birds, considerable amounts of these hormones were detected. Hypothyroidism did not seem to have profound or consistent effects on antibody production against SRBC or BA. The possibility that thyroid hormones play a role in antibody production was not ruled out. However, it was suggested that within the physiological range of thyroid gland activity, thyroid hormones may not significantly regulate antibody production.

Immunostimulating effect of triiodothyronine: dietary administration of triiodothyronine in rohu (Labeo rohita ) enhances immunity and resistance to Aeromonas hydrophila infection

“…Thus, the enhanced total protein and globulin levels observed here could be caused by the antibodytype of proteins. It indicated that thyroid hormones have control over immunoregulation along with immune development as noted earlier (Yam et al, 1981;Mashaly et al, 1983). Similarly, the percent mortality was significantly less in both groups B and C when compared with the control in responses to A. hydrophila challenge.…”

Neuroendocrine-Immune Interactions

“…A few investigators have reported that reduced serum thyroid levels, due to the administration of goitrogens (chemical thyroidectomy), result in a decreased antibody response (Yam et al, 1981;Kai et al, 1988). Other studies have reported that thyroid hormone levels have little effect on antibody levels (Martin et al, 1988) and that somewhat suppressed serum concentrations of thyroid hormone may actually enhance the primary antibody response (Mashaly et al, 1983). This effect seems to be dependent upon the degree of thyroid inhibition, in that high dosages of propyl thiouracil (PTU), which effectively suppresses thyroid hormone concentrations, do seem to inhibit the antibody response (Kai et al, 1988).…”

Effect of Thyroidectomy of Immature Male Chickens on Circulating Thyroid Hormones and on Response to Thyroid-Stimulating Hormone and Chronic Cold Exposure

“…Yet there have been several reports indicating that measurable levels of thyroid hormones exist in the circulation of the surgically thyroidectomized (T x ) dog (Kallfelz, 1973;Li et al, 1986), rat (Taurog and Evans, 1967;Obregon et al, 1981), Japanese quail (Peczely et al, 1980), chicken (Harvey et al, 1983;Mashaly et al, 1983;Bachman and Mashaly, 1986;1987), and radiothyroidectomized chicken (Mellen and Wentworth, 1962). The half-life of T 4 and T 3 in chickens lies in the range of a few hours in length (Singh etal., 1967;May et al, 1974;Davison, 1978), which is shorter than the half-life of the hormones' counterparts in mammalian species.…”