Replacement effect of vitamin E with grape polyphenols on antioxidant status, immune, and organs histopathological responses in broilers from 1-to 35-d age

A study was carried out to investigate the replacement effect of vitamin E with grape polyphenols (GPP) on antioxidant status, immune response, and organs histopathology in broilers from 1- to 35-d age. One-day-old Hubbard broiler chicks (n = 280) were randomly divided into 28 study units of 10 chicks each. A starter control diet was formulated having 22.5% CP, 3,200 kcal/kg ME, and 100 ppm vitamin E50 [50 IU DL-a-tocopheryl acetate (CON)]. Other dietary treatments were obtained by replacing vitamin E on wt:wt ratio, with 25 [low GPP (LGPP)], 50 [medium GPP (MGPP)], and 75 ppm [high GPP (HGPP)] GPP. Likewise, a control finisher diet (20% CP and 3,200 kcal/kg ME) and LGPP, MGPP, and HGPP diets were formulated having the same proportions of GPP and vitamin E as in the respective starter diets. Each dietary treatment was randomly assigned to 7 replicate pens. As a result of this study, by increasing GPP level in place of vitamin E, total phenolic contents in breast and leg muscles increased linearly (P < 0.05) whereas thiobarbituric acid reactive substances decreased quadratically with MGPP showing the lowest value (P < 0.05). Antibody titers against Newcastle disease virus were higher (P < 0.05) in broilers fed the LGPP and HGPP diets than in those fed the control diet. Antibody titers against infectious bursal disease virus were higher (P < 0.05) in broilers fed the HGPP diet than in all of the remaining dietary treatment groups. Histopathological examination of kidney and liver tissues showed no changes in birds fed LGPP and MGPP diets; however, mild effects were observed in some birds fed HGPP diet. Replacement of vitamin E with GPP resulted in lower cost per kg broiler feed. In conclusion, replacement of 75 ppm vitamin E with GPP improved antioxidant status and immune response of broilers at lower feed cost without any significant effect on histopathology of organs.