Effect of sorghum tannins on ruminal fermentation and sheep nutritional parameters

Author(s)

Sérgio Lucio Salomon Cabral Filho

• Document type: Doctoral Thesis
• Press: Piracicaba. , gráficos, ilustrações, tabelas.
• Institution: Universidade de São Paulo (USP). Centro de Energia Nuclear na Agricultura (CENA/STB)
• Defense date: 2004-04-15

Examining board members

Adibe Luiz Abdalla; Ciniro Costa; Jose Avelino Santos Rodrigues; Paulo Henrique Mazza Rodrigues; Ivanete Susin

• Advisor: Adibe Luiz Abdalla
• Field of knowledge: Agronomical Sciences - Animal Husbandry
• Indexed in: Banco de Dados Bibliográficos da USP-DEDALUS; Biblioteca Digital de Teses e Dissertações - USP
• Location: Universidade de São Paulo. Biblioteca do Centro de Energia Nuclear na Agricultura; CENA (043); C117e 10057

Abstract

Sorghum bicolor (L.) Moench is an important cereal crop used in animal nutrition. However, this plant produces secondary compounds, such as condensed tannin, which are able to interfere in the animal digestion. Condensed tannins are macromolecules that can bind to other molecules such as protein and carbohydrates reducing the fully utilization of nutrients by the animals. The aim of this work was to evaluate the anti-nutritional effects of tannins present in sorghum on sheep nutrition. This study was divided in two trials. In the first trial eight cultivars of sorghum with different purposes were evaluated through the in vitro gas production technique measuring the fermentation parameters and dry matter degradability. The cultivars were cultivated in four blocks and harvested at 30, 60, 90 and 120 days post planting. Grains were collected at 120 days post-plant. The anti-nutritional effects of sorghum were evaluated through the bioassay technique by measuring increase in gas production due to addition of poly-ethylene-glycol (PEG 6000). The second trial evaluated the tannins effects using sorghum grain for sheep fed high concentrate diets. Three diets, C0, C1 and C2, containing 0, 1.9 and 2.4% condensed tannin, respectively, and formulated from three different sorghum cultivars were evaluated. Six male and adult sheep (≅ 56 kg), fitted with ruminal and duodenal cannulaes, were kept in metabolic cage. This trial was designed in a double Latin Square 3 x 3 simultaneously, with 3 periods and 3 treatments. It was determined voluntary intake, nitrogen balance (NB) and dry matter, neutral detergent fiber and crude protein apparent digestibility. Concentrations of microbial nitrogen (MN) were determined through 15N tracer. Results in the first trial demonstrated high nutritional value of sorghum. Cultivars with grain purpose or with double purposes promoted higher microbial fermentation at 60, 90 and 120 days post planting. In the second trial, the diets containing tannins (C1 and C2) presented lower NB although decreasing in MN concentrations in the duodenum was not observed. (AU)