EFFECT OF SOME TREATMENTS ON IN SITU DRY MATTER AND CRUDE PROTEIN DEGRADATION OF SOME RANGE PLANTS IN THE NORTH WEST COAST REGION, EGYPT

An experiment was conducted to evaluate the nutritive value of six dominant range plants in Wadi Hashim, North West Coast, Egypt, through the estimation of chemical composition and in situ dry matter (DM) and crude protein (CP) degradation kinetics. In addition, plants were treated by different processes, such as ensiling or addition  of Poly Ethylene Glycol (PEG) in comparison with those without treatment (as fed). The plants belong to 6 families: Thymelaea  hirsuta (family: Thymelaeaceae); Lycium shawii (f: Solanaceae); Asphodelus fistulosus (f: Liliaceae); Silybium marianum (f: Compositae); Pituranthos tortuosus (f: Umbelliferae) and Suaeda vermiculata (f: Chenopodiaceae). The DM and CP degradation kinetics were evaluated by the artificial fiber bag technique through in situ procedure, using three ruminally cannulated camels. Chemical composition of the studied plants showed that Suaeda vermiculata followed by Lycium shawii contained higher CP (12.8 and 11.9%, respectively). Treatments as ensiling process or  treatment with PEG improved chemical composition of the experimental plants. Degradation profile of DM indicated that the higher values of the rapidly degradable fraction ‘a’ were recorded in S. marianum followed by A. fistulosus in all of their forms (as fed, silage or treated with PEG) while S. vermiculata recorded high value in silage form only (42.4%). The fraction ‘a’ was generally low across the studied plants as fed and those treated with PEG. However, the slowly degradable fraction ‘b’ differed among plant species, being high in A. fistulosus and S. marianum  with 60.4, and  59.3% DM (as fed),  57.3 and 56.8% DM (treated with PEG) and 57.7 and 62.1% DM (when ensiled), respectively. Concerning the CP degradability, it was found that the soluble fraction “a” was low as in T. hirsute, P. tortuosus and  S. vermiculata (as fed, 10.5, 21.7 and 23.5% CP, respectively) and it was irregularly affected with PEG addition to become 31.5, 23.5 and 19.6% CP, respectively, and slightly increased when ensiled to become 24.5, 23.4 and 31.2% CP, respectively. Meanwhile, the slowly fraction “b” was not affected in a uniform pattern when treated with PEG or ensiled. The slowly fraction was reduced in T. hirsute and A. fistulosus when treated with PEG or ensiled when compared with their values as fed.   Results indicated that the contents of anti-nutritional factors, total and condensed tannins and saponin, in the studied plants were reduced with treatment, particularly ensiled ones. Based on these findings, it can be concluded that the nutritive value of  the  forage  plant species are improved with treatment  and can be used as supplement when ensiled.