Feed Intake and Utilization of Soduim Hydroxide-Treated Rice Straw as Affected by Supplements of Cassava Peels and Treated Water Hyacinth

Abstract

Several strategies such as chemical treatment and supplementation have been used in an attempt to improve the quality of rice straw as a feed for livestock. Protein and energy supplementation has been shown to improve the nutritive value of straw. Three experiments were conducted on the hypothesis that ensiled water hyacinth, with or without cassava peels, will enhance the utilization of the basal diet of NaOH-treated rice straw and addition of dried cassava peels to ensiled water hyacinth will supply readily available energy and thus improve growth of sheep when fed as a supplement to a basal diet of NaOH- treated rice straw. Experiment one compared the nutrient digestibility and nitrogen retention of NaOH- treated rice straw supplemented with: ensiled water hyacinth leave (WHL) diet 1, ensiled water hyacinth whole plant (WHLS) diet 2, ensiled water hyacinth leave + cassava peels (WHLCP) diet 3, ensiled water hyacinth whole plant + cassava peels (WHLS-CP) diet 4 and sodium hydroxide-treated rice straw alone (ENS) diet 5, in 5x5 Latin square design. The difference between nutrient digestibility of dry matter, neutral detergent fiber and organic matter for WHL-CP and WHLS-CP was both significant (p<0.05) and both where superior to WHLS, WHL and ENS. For the crude protein digestibility the difference between WHLS and WHL were both significant (p<0.05) and where both superior to WHLS-CP, WHL-CP and ENS. The mean nitrogen retained were also significantly different (p<0.05), the values were1.32±1.5, 2.15±0.8, 3.28±1.5, 2.52±1.6, -4.3±1.9 for WHL, WHLS, WHL-CP, WHLSCP and ENS respectively. Experiment two compared the effect of WHL, WHLS, WHL-CP and WHLS-CP on voluntary feed intake, digestible organic matter in dry matter, and metabolized energy intake and growth rate of djallonke sheep. Significant differences (p<0.05) were observed in all these measurement. The mean feed intake values were 689.59g/d, 6.59.94g/d, 596.77g/d and 527g/d for WHLS-CP, WHL-CP, WHLS and WHL respectively. The mean values for the metabolized energy (MJ/KgD) intake were 7.6±3.9, 7.3±3.1, 6.6±2.0 and 6.6±1.2 for WHLSCP, WHL-CP, WHLS and WHL respectively. Similar trend was observed for the digestible organic matter digestibility in dry matter. Significant differences were also observed with growth rate, with WHLS and WHL, having a negative growth rate. The studies in experiment three shows that effective degradability of dry matter and crude protein with take into account the flow rate were higher with WHLS-CP and WHL-CP compared with WHLS and WHL. The various diets did have significant difference (p>0.05) on rumen pH. Significant differences (p<0.05) were however observed with the mean rumen ammonia values. The values observed were 4.26±2.5mg/dl, 5.31±0.46mg/dl, 2.23±0.13mg/dl, and 3.31±0.22mg/dl for WHL, WHLS, WHL-CP and WHLS-CP respectively. The result from this study shows that although water hyacinth is high in protein and could be fed as a supplement to poor quality straw, for effective influence on animal performance it should not be fed alone as a supplement but together with rumen un-degradable protein or energy such as cassava peels.