Two experiments were conducted to evaluate the effect of supplemental Gin on growth performance, development of the gastrointestinal tract, and humoral immune response of broilers. Immediately after hatch 6 replicate pens of 6 chicks were randomly assigned to I of 7 (experiment 1) or 5 (experiment 2) dietary treatments for 21 d. On d 4, 7, 14, and 21, twelve chicks per treatment (2 chicks/pen) were killed for thymus, spleen, bursa, duodenum, jejunum, ileum, bile, and blood sample collections and weights. In experiment 1, the effect of 1 or 4% Gin addition to the feed, Water, or both was compared with a corn-soybean meal (SBM) control diet. All diets were formulated to be isocaloric and isonitrogenous. Weight gain improved significantly (P < 0.05) when chicks were fed diets with 1% Gln as compared with chicks fed the control diet (11% average improvement). The addition of 4% Gin to the diet or water depressed (P < 0.05) growth performance. Based on the results from experiment 1, 1% Gin supplementation to the diet was determined to be ample and most practical. Thus in experiment 2, diets supplemented with 1%, Gin were fed for 4, 7, 14, or 21 d after which time chicks were fed the corn-SBM control diet until the experiment was terminated at 21 d. Weight gain improved significantly (P < 0.05) when chicks were fed diets supplemented with 1% Gin throughout the 21-d study. In both experiments, chicks fed diets supplemented with 1% Gin for 21 d had higher concentrations of bile, intestinal, and sera IgA and sera IgG (P < 0.05). Chicks fed diets with 1% Gin had heavier intestinal relative weights and longer intestinal villi (P < 0.05) as compared with the chicks fed the corn-SBM diet. Our results indicate that the addition of 1% Gin to the diet of broiler chicks improves growth performance and may stimulate development of the gastrointestinal tract and humoral immune response.
