The effect of feeding whole branch of Albizia lebbeck tree on digestibility, some fermentation characteristics and rumen protozoa population of Najdi goats

Generally, more than 50% of animal production costs are belong to feeding, since farmers and animal nutritionist are looking for the ways to reduce these costs. Therefore, use native or local plants resources make us closer to this purpose (Patra et al. 2003). Leguminous leaves foliage are used as a high-quality feed resource for livestock (Eryavuz and Dehority 2004). The Albizia lebbeck (siris) may be used as a rich source of nitrogen in the diet of ruminants, this plant contains low fiber, and high minerals, vitamins and saturated fatty acid, and no cholesterol (Patra et al. 2003). This tree is native to tropical regions of Africa and Asia. It is planted in the provinces of Khuzestan, Bushehr, Fars and Hormozgan in Iran. The Albizia lebbeck is a tree with a height of 30 meters in native regions, but in Iran rarely reaches to 12 meters. This tree beginning to flowering is in early of May (Mozafarian 2005). Cyanide, oxalate, saponin and trypsin inhibitors are anti nutrients components of the Albizia lebbeck, and the saponins content of the seeds and pods is more than other sections of the plant (Zia-ul-haq et al. 2013). The Albizia lebbeck inproved the digestibility of dry matter in low quality rations (Lowry 1990). Since Albizia lebbeck is plenty in Khuzestan as tropical climate, and has some anti-nutrients factors, the aim of present experiment was to investigate the possibility of replacing the Albizia lebbeck with alfalfa hay in the diet of goats.
Material and In this experiment, the pods and leaves of the Albizia lebbeck were freshly collected from the fields around Mollasani in north of Ahvaz, the capital of Khuzestan, and the farms of the Khuzestan Agricultural Sciences and Natural Resources University, then dried under the shade in open air. Feed intake, nutrient digestibility, rumination, rumen fermentation parameters, blood parameters and rumen protozoan population of Najdi goats were studied. In this experiment, 12 Najdi goats with an average 30±2 kg boby weight were assigned to experimental diets as a completely randomized design with three treatments and 4 replicates for 45 days. The three experimental diets included replacement of 50 and 75% Albizia lebbeck with alfalfa and the control diet without Albizia lebbeck. The diets were formulated according to tables requirements of NRC (2007). Chemical composition of experimental samples including crude protein (CP), ether extract (EE), neutral detergent fiber (NDF), dry matter (DM), acid detergent fiber (ADF), total tannin and some minerals were measured according to the standard methods. The apparent digestibility of nutrients (DM, NDF, and ADF) were measured during 7 days by total collection method for feces, and recording of feed dry matter intake and orts. Chewing activity (eating and rumination time) was visually recorded for 24 h with 5 minute intervals for all goats, then corrected per NDF, DM and ADF intake. Rumen fluid of all goats was collected at the end days of experiment through stomach tubes at 3 h post feeding. pH was measured immediately, and rumen fluid was filtered by four layer of cheesecloth, mixed with 0.2 M hydrochloric acid in equal volume, and stored at -20 ᵒC for measurement of ammonia nitrogen. Blood sampling from all goats was conducted via jugular vein by sterile plastic syringe, at 4 h post feeding. The blood samples were centrifuged (3000 × g, 15 minutes) and plasma removed for subsequent analysis. Glucose, cholesterol, blood urea nitrogen (BUN) measured with laboratory kits (ParsAzmoon) using a spectrophotometer. After collection of rumen fluid, it was mixed with formaldehyde 18.5% for fixation of the protozoa, and they were counted under microscope using hemocytometer lam (Dehority 2003).
In study of Yusefi et al. (2017), Dwatmadji et al. (1992) and Balogun et al. (1998) the CP in leaves of Albizia lebbeck reported 22.4, 17.50 and 24%, respectively that was near our results (21.4% of DM). In an experiment NDF, ADF and EE of Albizia lebbeck leaves were 46.9, 33.7 and 5.4%, respectively, which was consistence with the results of present study. Our results showed that crude protein and fat of leaves and pods of Albizia lebbeck was more and ADF less than alfalfa hay. The concentration of all minerals, except potassium, in whole branch of Albizia lebbeck were higher than alfalfa hay. Nutrients (DM, OM, NDF, ADF and CP) intake and digestibility in diets containing Albizia lebbeck were more than control diet, and diet containing 75% Albizia lebbeck had highest values. Khy et al. (2012) reported increased in dry matter intake, when added pelleted subabul to diet of swamp buffalo, which fed on paddy straw and concentrate. The Albizia lebbeck in diet of goat increased apparent digestibility of dry matter, CP, NDF and ADF (P Therefore, the results of present experiment showed that at the levels proposed in the present experiment (replacement of 50 and 75% Albizia lebbeck with alfalfa), Albizia lebbeck might be used without any negative effect on digestion, fermentation and metabolism in the diet of goats.