363 In Vitro dry Matter and Fiber Digestibility of Different Varieties of Peanut Tops and Bermuda Grass Forage

Abstract

Abstract The objective of the current study was to evaluate the in vitro of dry matter and fiber digestibility, gas, ammonia N and volatile fatty acid production of peanut tops from seven cultivars, CB91-1, 010-13, IAC322, 13-D, 13-1014, 886 and GA-06G, grown in the state of Georgia, USA, and Bermuda grass. The peanut top samples were harvested towards the end of the growing season at about 125 days after planting and the peanut pods removed. The Bermuda grass was harvested after 4 weeks regrowth. Fresh cut peanut tops and Bermuda grass samples were analysed for dry matter (DM) content and then in vitro DM and fibre digestibility. Hydrogen, methane, pH, ammonia, total gas and volatile fatty acids (VFA) production were measured after 24 hours incubation. Analysis of variance was performed using the General Linear Model procedures of Minitab Statistical package. The peanut top varieties contained an average of 165.4 g/kgDM crude protein, and greater calcium and potassium and less phosphorus than Bermuda grass. There were no significant differences (P > 0.05) in in vitro DM digestibility, pH, hydrogen, methane, ammonia-N production. However, NDF and ADF in the Bermuda grass was significantly more digestible (P < 0.05) than the peanut varieties. The peanut tops did not differ in NDF digestibility (P > 0.05). CB91-1, IAC322 and 886 peanut tops and Bermuda grass had significantly greater (P < 0.05) ADF digestibility. There was no significant difference in the acetate contents for all seven peanut varieties (P > 0.05). The GA-06G variety had the greatest propionate and butyrate content. Bermuda grass and CB91-1 variety had the least amount of propionate, isobutryate, butyrate, isovalerate and valerate compared with other peanut varieties. Total VFA of all peanut varieties were similar, while that of Bermuda grass was the least (P < 0.05). The GA-06G had the lowest A:P ratio value compared with the other samples.