Vitro ruminal starch degradability in 21 Sorghum (Sorghum bicolor L. Moench) varieties with different draught resistance genotypes

Abstract

In vitro ruminal starch degradability was determined in 21 sorghum varieties with different drought resistance response (7 resistant, 6 intermediate and 8 susceptible). Starch degradation was measured after 12h incubation with ruminal microbes. Mean starch concentration was 68.3\% (59.0-74.6\%). There were no differences in starch content among genotypes (susceptible 67.4\%; intermediate 68.5\%; and resistant 69.1\%). Mean starch degradability was 58.1\% (48.8-70.6\%) with no differences among genotypes (susceptible 58.8\%; intermediate 58.2\%; susceptible 57.5\%). Mean degradable starch was 39.7\% (29.3-48.7\%) without differences among genotypes (susceptible 38.9\%; intermediate 39.8\%; resistant 40.6\%), presenting variation within genotypes. There were no differences in starch or cell wall content according to the degree of drought resistance; however some varieties like UAT 125 and UAT 152 stand out because of their larger degradable starch content, which can be useful in ruminants feed.