Replacement of part of diet hay with leaf of jujube tree and its effect on digestibility, some parameters of blood and fermentation of rumen in lambs of Baluchi

Introduction[1]In most part of Iran, low rainfall and availability of water resources are the major limitations to the farmer.Feed represents a major proportion of the overall production cost for livestock industry across the world. On the other hand, availability of good quality and unadulterated conventional feed all year round is a major constraint in livestock production. Thus, proper use of expensive agricultural by-products is important goal in livestock production. Therefore, one way to overcome the limitation of forage resources and the high cost of livestock feed is using agricultural by products such as plant leaves or other unconventional sources of the feed. Jujube is a short tree with a height of 2 to 8 meters and sometimes up to 12 meters and is very resistant to drought. The cultivation area of jujube in Iran is about 3,000 hectares, more than 95% of which (about 2850 ha) is in southern Khorasan and 4,200 tons of jujube is produced.  The leaves are readily eaten by camels, cattle and goats and are considered nutritious. Analyses has shown the following constituents (% dry weight): crude protein, 12.9-16.9; fat, 1.5-2.7; fiber, 13.5-17.1; N-free extract, 55.3-56.7; ash, 10.2-11.7; calcium, 1.42-3.74; phosphorus, 0.17-0.33; magnesium, 0.46-0.83; potassium, 0.47-1.57; sodium, 0.02-0.05; chlorine, 0.14-0.38; Sulphur, 0.13-0.33%. The goal of the experiment was to investigate the effects of different levels of jujube leaves on yield, digestibility and fermentation characteristics of Baluchi male lambs. Materials and Methods Jujube leaves were analyzed for dry matter (DM), organic matter (OM), crude protein (CP) and ether extract (EE) contents using standard procedures (AOAC, 2005). Neutral detergent fiber (NDF) was analyzed according to Van Soest et al. (1991), total phenols (TP) and total tannins (TT). Twenty-four Baluchi male lambs with the age of 140±10 days were assigned to a completely randomized design with 3 treatments and 8 replicates for 75 days 3 dietary treatments and 8 replications in a completely randomized design. Lambs were grouped based on their age and weight. Weight and experimental trail lasted for 75 days. Diets were formulated based on SRNS (1.9.6069) guidelines. Concentrate diet and dried alfalfa hay were used in the experiment. All lambs were fed ad libitum twice daily at 08:00 and 20:00 h with a Total Mixed Ration (TMR) of 30% forage (Alfalfa) and 70% concentrate. The dietary treatments were 1) control (without jujube leaves), 2) 6% jujube leaves, and 3) 12% jujube leaves. An adaptation period of 15 days and an experimental period of 75 days were considered for this experiment. During the experimental period, feed distributed to each animal and corresponding ort were recorded daily. Representative samples of feed and ort were bulked for subsequent analyses. Animal BW was recorded at every 10 days of the experiment after 16 h fasting, to calculate weight gain. In order to directly measure the apparent digestibility of nutrients during 10 days at the end of the experiment, samples were collected from the feeds and their residues and the fecal was collected in the last 7 days. Sampling of rumen fluid was done on days 25th, 50th and 75th of the experimental period, 2 hours after ingestion in the morning using an esophagus tube and its pH was determined immediately. For determination of nutrients digestibility, the amount of feed intake, ort and fecal excretion were recorded. On the 25th, 50th and 75th days of the experimental period, approximately 10 mL of blood was collected from the jugular vein of each. Blood was collected in a tube and directly centrifuged at 3000 rpm for 10 min at room temperature. The supernatant (serum) was collected and frozen at −20 °C pending further analysis. Blood serum metabolites, glucose, HDL, LDL, cholesterol and blood urea nitrogen were measured. Results and Discussion The results of the experiment showed the amount of dry matter, organic matter, crude protein, ash, ether extract, NDF and ADF of jujube leaves were 93.93,88.70, 7.61, 11.30, 1.8, 41.50 and 13.50%, respectively. Also, total phenol, total tannin and condensed tannin were reported to be 4.7, 3.1 and 0.48% respectively. The results of the experiment showed that the use of different levels of jujube leaves had no significant effect on mean daily weight gain and feed conversion ratio, but in jujube leaves treatments, the average daily feed intake was significantly decreased.The digestibility of crude protein in jujube leaves treatments significantly decreased compared to control. The digestibility of dry matter, organic matter, NDF and ADF did not have a significant effect on the treatments (P> 0.05), but the digestibility of crude protein in jujube leaves treatments significantly decreased compared to control (p < 0.05). The pH of the ruminal fluid decreased linearly with increasing levels of jujube leaves, but did not have a significant effect on ruminal ammonia nitrogen concentration. Blood glucose concentration, HDL, LDL, cholesterol and blood urea nitrogen were significantly affected by the treatments. Conclusion According to results of this experiment, the use of jujube leaves in the diet due to the presence of tannin reduced feed intake, digestibility of crude protein, blood glucose concentration and blood urea nitrogen and did not have a negative effect on the pH of the rumen fluid.