Effects of Increasing Level of Metabolizable Energy and Protein on Feed Intake, Nutrient Digestibility, Performance and Blood Metabolites of Zell Pregnant Ewes at Late Gestation

IIn order to study the effects of increasing level of metabolizable energy and protein on feed intake, improve nutrient digestibility, performance and blood metabolites of Zell pregnant ewes at late gestation, 32 pregnant ewe (mean body weight 42.1 kg, 2.5 years-old, multiparous, 100 days of pregnancy) were used in completely randomized design with 4 treatments and 8 replicates. Treatments were included: 1) diet adapted to the requirement of pregnant ewes in accordance with the metabolizable energy and protein recommended in (NRC, 2007) on the 100th day of pregnancy (control). 2) diet with a high level of metabolizable energy (+10NRC) with corn. 3) diet with the high level of metabolizable energy (+10NRC) with micro-capsulated flax seed. diet with the high level of metabolizable protein (+10NRC) with Lys and Met. The results showed that nutrient consumption and digestibility of nutrients significantly increased in treatments with an increased level of metabolizable energy and protein (P <0.0231). The treatments with synthetic amino acids had the highest dry matter and digestibility. The effects of experimental treatments on rumen fluid pH and volatile fatty acids were not significant. Ammonia nitrogen content of ruminal fluid was significantly higher in control group (P<0.05). Increasing levels of metabolizable energy and protein could significantly reduce the weight loss and body condition score (P<0.001). The treatments with the high level of metabolizable energy were able significantly to avoid to reduce energy carriers (glucose, cholesterol, triglycerides) and also reduce the level of ketone bodies and NEFA in blood metabolites (P<0.0071). Generally according to the results of this study increasing levels of metabolizable energy and protein in rationy could be prevented to negative energy balance and metabolic disorders in pregnant ewes at late gestation.