Effects of dietary Quebracho tannin on some morphological, biological and productive features of White Leghorn pullets

This study aimed to evaluate the effect of adding two levels of vegetal tannins from Schinopsis lorenzii to a commercial crumbled diet for pullets to be destined to organic farms. The main objective was to verify if Quebracho tannin ingestion could modify intestine morphology. Since gut lengthening is beneficial to increase the absorptive surface in intestine in free range birds, the inhibitory effect of tannin compounds on intestinal digestion could be compensated. Ninety-nine 35-day old Leghorn females were randomly assigned to three dietary treatments: 1%, 3% and 0% of Quebracho tannin powder (MGM-S product, manufactured by Unitan s.a.i.c.a., Buenos Aires). Three replicates of 11 birds/ pen/ treatment were performed. At 49 days of age the 3% dietary tanning group showed a critical body weight decrease, consequently the dietary tannin level was reduced to 2%. Data on feed consumption and body weight gain was collected twice a month till the end of the experimental trial, at the age of 176 days. Blood samples were collected twice (age 64 and 172 days) to verify plasma total protein level. At 70 and 174 days of age excreta samples were used to determine parasite load. At the end of the trial, 6 birds per treatment were sacrificed to collect data on slaughtering traits and length measurements of small intestine and caeca. Body weight of group receiving the highest Quebracho tannin level was significantly lower than the other two groups till 147 days of age. After one month of dietary treatment, plasma total protein level was similar among groups. Three and a half months later (172 days of age) control group showed the highest level of plasma total protein (P<0.001). Treated birds had longer caeca than control birds (P