Improving the utilization of stylosanthes guianensis CIAT 184 in rice straw-based ration with the inclusion of tannin-containing legume for sheep

A study was conducted to enhance the utilization of stylo CIAT 184 as protein source in rice straw (RS)-based ration for sheep. The production responses of sheep, nutrient digestibility, rumen fermentation indicators and the economics of supplementing Stylo (S) alone or in a mixture with tannin-containing Flemingia (F) were determined. Eighteen male growing sheep were randomly alloted to three treatments (T1-50 percent RS + 50 percent C, T2-50 percent RS + 50 percent S and T3-50 percent RS + 40 percent S + 10 percent F) in randomized complete block design. The feeding trial lasted for 14-day preliminary and 60-day experimental periods. A digestion trial was conducted at the middle of the 60-day feeding trial. Rumen fermentation indicators were determined before and 3 hrs after feeding the rations. There were no significant differences in DMI [dry matter intake], as percent of live weight, among treatments. However, sheep fed RS + S + F gained liveweight and had feed efficiency comparable with those in RS + C which gave the highest ADG [average daily gain]. Sheep fed RS + S performed comparably with those fed RS + S + F but significantly poorer than those fed RS + C. The similar animal performance (ADG) of sheep supplemented with mixture of Stylo + Flemingia (T3) with those supplemented with concentrate (T1) can be attributed to the by-pass protein provided by the tannin-containing Flemingia and similar N utilization as observed from the insignificant differences among values for CPI [crude protein intake], N balance and efficiency of N utilization. Supplementation of Stylo alone or mixture of Stylo + Flemingia significantly improved the apparent digestibility of some proximate and cell wall components and digestible nutrients but not the total digestible nutrients. All rations decreased the rumen pH but increased total volatile fatty acids production 3 hours after feeding. Supplementations of Stylo and the mixture of Stylo + Flemingia lowered the total feed cost and feed costs/kg gain per day. Concentrate supplementation was the most expensive practice for apparent reason, while supplementation of mixtures of legumes was the most economical