Influence of a purified grade of pentachlorophenol on the immune response of chickens

SUMMARY Broiler chickens were fed a purified grade of pentachlorophenol ( pcp ) at dosages of 0, 600,1,200, and 2,400 μg/g of feed (0,600,1,200, and 2,400 ppm, respectively) for 8 weeks. In all treatment groups, kidney weights were increased and spleen and bursa of Fabricius weights were decreased. Body weights were decreased and liver weights were increased in the 1,200- and 2,400 μg treatment groups. In chickens fed 600 μg of pcp /g, body weights were initially lower, but by week 7 were not different from weights of controls. Microscopic lesions were not found in any of the groups. There was a significant positive linear relationship between pcp accumulation in the tissues and the concentration of pcp in the feed. Accumulation of pcp was greatest in the kidney, followed by accumulations in the liver, fat, and pectoral muscle. Humoral and cell-mediated immune responses of chickens fed 0, 600, and 2,400 μg of pcp /g were evaluated. There were no significant differences between the 600-μg treatment group and the controls in serum concentrations of immunoglobulin (Ig) M and IgG; in the humoral responses to sheep rbc , bovine serum albumin, or Newcastle disease virus; in the cutaneous reactions to phytohemagglutinin P, purified protein derivative, or dinitrochlorobenzene; or in wbc numbers. The in vitro lymphoproliferative response to phytohemagglutinin P was within a normal range, but response to concanavalin A was significantly lower ( P < 0.01). Chickens fed 2,400 μg of pcp /g had significantly lower humoral responses to bovine serum albumin ( P < 0.02), significantly lower wbc counts ( P < 0.0001), and significantly decreased lymphoproliferative responses to concanavalin A ( P < 0.01) and phytohemagglutinin P ( P < 0.05), but serum concentrations of IgM and IgG and the humoral responses to sheep rbc and Newcastle disease virus were normal.