Efficacy test of a hydrolysable tannin extract against necrotic enteritis in challenged broiler chickens

A hydrolysable tannin extracted from chestnut (SaviotaN (R)) was tested for efficacy in controlling the proliferation of Clostridium perfringens in the gut of broiler chickens challenged via oral gavage first with coccidia (Eimeria tenella, Eimeria acervulina, Eimeria maxima) at the age of 10 days, and then with Clostridium perfringens at the age of 15 days. We randomly allocated 150 broiler chickens within 5 poultry isolators (30 birds each). Dietary treatments consisted of a basal diet (C) composed of corn [575 g/kg on dry matter (DM)] and soybean meal (100 g/kg DM), barley bran (220 g/kg DM), corn gluten feed (30 g/kg DM), soybean oil (25 g/kg DM), vitamin mineral premix (49.5 g/kg DM), and four other diets obtained by adding chestnut tannin extract (1.5, 3, 5, and 12 g/kg during week 1, 10.0 g/kg during week 2, and 8.0 g/kg during the last two weeks, respectively) to C. At the age of 20 days, 15 birds/group were euthanised and individually examined for the level of gut infection by counting Clostridium perfringens and macroscopic gut lesions. Results demonstrated that chestnut tannin gave significant results even at low concentration levels in the feed (1.5 to 3.0 g/kg), but was actually efficient in controlling necrotic enteritis at levels >= 5.0 g/kg. The treatment (12.0 g/kg during the first week and 8.0 g/kg during the last two weeks of age) resulted very efficient in controlling the proliferation of Clostridium perfringens and in reducing the severity of gut damage compared to the untreated infected group.