پديد آورندگان :
طباطبایی محمد مهدی نويسنده عضو هیئت علمی Tabatabaei Mohammad Mahdi , زمانی پویا نويسنده عضو هیئت علمی Zamani Puya , افروزی سپیده نويسنده دانش اموخته كارشناسی ارشد Afrouzi Sepideh , زابلی خلیل نويسنده عضو هیئت علمی Zaboli Khalil
چكيده لاتين :
Introduction Feed supplements can improve nutritional value of ruminant’s diet. According to many studies, urea molasses-mineral block (UMMB) is a good source of easily available nitrogen and fermentable energy and its usage causes nitrogen and energy available for rumen microorganisms simultaneously and improves feed efficiency especially in low quality feeds. Increased dry matter intake is reported when UMMB was included in the diet of buffalo. It was observed that increasing digestibility of dry matter, crude protein, NDF and ADF in cows by using UMMB. Also better availability of fermentable energy for rumen microorganisms was seen. Monensin, as a feed additive through the manipulation of rumen fermentation, increases feed efficiency in ruminants. This substance selectively inhibits gram-positive bacteria, thereby impacting ruminant metabolism by increasing efficiency of energy metabolism, improving nitrogen metabolism, and reducing bloat and lactic acidosis risk. Monensin may provide an additional energetic benefit from enhanced forage digestibility. In order to evaluate the effect of UMMB enriched with monensin on performance, digestibility, and some blood and rumen parameters in male lambs, two experiments were conducted in a factorial arrangement as a completely randomized design.
Materials and Methods Ingredients used to manufacture UMMB were cotton seed meal (21%), wheat bran (19.7%), urea (2.5%), molasses (43.3%), calcite (3.4%), mineral supplement (4.2%) and common salt (5.9%). In the first experiment, 24 male lambs with 7-8 month age were randomly divided into 4 groups including 1) concentrate mixture and forage, 2) concentrate mixture and forage + 30 ppm monensin, 3) concentrate mixture and forage (85%) and UMMB without monensin (15%), and 4) concentrate mixture and forage (85%) and UMMB enriched with monensin (15%). During the experimental period (70 days), dry matter intake and body weight gain were measured daily and fourth nightly, respectively. Blood and rumen fluid samples were taken on days 68 and 69, respectively, 3 hours after the morning feeding. For the second experiment, 4 lambs from each treatment were randomly selected and transferred to metabolic cages to determine the effects of UMMB and monensin on nutrients digestibility and nitrogen retention. Data were analyzed as a 2×2 factorial experiment based on a completely randomized design using the GLM procedure of SAS (1999).
Results and Discussion The results showed that UMMB increased dry matter intake, daily weight gain and decreased feed conversion ratio (P <0.05). Monensin had no effect on dry matter intake but increased daily weight gain and feed conversion ratio (P <0.05). Higher dry matter intake seen in the groups receiving UMMB may be due to higher palatability of diet and higher microbial activity because of simultaneously available nitrogen and energy. UMMB had no effect on digestibility of nutrients except for protein. Monensin increased digestibility of dry matter and crude protein (P <0.05). Significant effect of treatment was observed on urine nitrogen and nitrogen retention (P <0.05). Effect of diet on urinary nitrogen and nitrogen retention was significant (P <0.05). UMMB caused significantly lower excretion of nitrogen through urine and higher retention of nitrogen (P <0.05). Monensin also, decreased excretion of nitrogen through the urine and feces consequently increased absorption and retention of nitrogen (P <0.05). Treatment 1 had lowest nitrogen absorption and retention and treatment 4 showed highest nitrogen retention (P <0.05). Increased nitrogen retention is seen in treatments received monensin may be due to improved digestibility of protein in lower tract. Improved nitrogen retention with UMMB and monensin showed that block and monensin had higher ability to synchronize usage of nitrogen and fermentable energy by rumen microorganisms. Significant effect of diet was seen on total concentration of volatile fatty acid (TVFA) and rumen pH (P <0.05). However TVFA was not affected by monensin. Treatments receiving UMMB had significantly higher concentration of TVFA, which implicates higher availability of fermentable energy coming from molasses (P <0.05). Effects of diet and monensin on plasma glucose concentration were significant, as treatment 4 had highest and treatment 1 had lowest plasma glucose concentrations (P <0.05). UMMB without monensin significantly increased plasma urea concentration but monensin decreased it (P <0.05). This shows that urea used in UMMB increased ammonia concentration in the rumen and consequently increased plasma urea concentration. But monensin may have increased efficiency of ammonia used by rumen microorganisms therefore decreased plasma urea concentration.
Conclusion Overall results showed that UMMB improves efficiency of fermentable energy and nitrogen, dry matter and crude protein digestibility and nitrogen retention in lambs. So it can be concluded that UMMB may be used to improve performance of growing male lambs.
Materials and Methods: Ingredients used to manufacture urea mineral molasses block were cotton seed meal (21%), wheat bran (19.7%), urea (2.5%), molasses (43.3%), calcite (3.4%), mineral supplement (4.2%) and common salt (5.9%). In the first experiment, 24 male lambs with 7-8 month age were randomly divided into 4 groups including 1) concentrate mixture and forage, 2) concentrate mixture and forage + 30 ppm monensin, 3) concentrate mixture and forage (85%) and urea mineral molasses block without monensin (15%), and 4) concentrate mixture and forage (85%) and urea mineral molasses block enriched with monensin (15%). During the experimental period (70 days), dry matter intake and body weight gain were measured daily and fourth nightly, respectively. Blood and rumen fluid samples were taken on days 68 and 69, respectively, 3 hours after the morning feeding. For the second experiment, 4 lambs from each treatment were randomly selected and transferred to metabolic cages to determine the effects of urea mineral molasses block and monensin on nutrients digestibility and nitrogen retention.
Results and Discussion: The results showed that urea mineral molasses block increased dry matter intake, daily weight gain and decreased feed conversion ratio (p <0.05). Monensin had no effect on dry matter intake but increased daily weight gain and feed conversion ratio (p <0.05). Higher dry matter intake seen in the groups receiving urea mineral molasses block may be due to higher palatability of diet and higher microbial activity because of simultaneously available nitrogen and energy. Urea mineral molasses block had no effect on digestibility of nutrients except for protein. Monensin increased digestibility of dry matter and crude protein (p <0.05). Significant effect of treatment was observed on urine nitrogen and nitrogen retention (p <0.05). Effect of diet on urinary nitrogen and nitrogen retention was significant (p <0.05). Urea mineral molasses block caused significantly lower excretion of nitrogen through urine and higher retention of nitrogen (p <0.05). Monensin also, decreased excretion of nitrogen through urine and feces consequently increased absorption and retention of nitrogen (p <0.05). Treatment 1 had lowest nitrogen absorption and retention and treatment 4 showed highest nitrogen retention (p <0.05). Increased nitrogen retention is seen in treatments received monensin may be due to improved digestibility of protein in lower tract. Improved nitrogen retention with urea mineral molasses block and monensin showed that block and monensin had higher ability to synchronize usage of nitrogen and fermentable energy by rumen microorganisms. Significant effect of diet was seen on total concentration of volatile fatty acid (TVFA) and rumen pH (p <0.05). However TVFA was not affected by monensin. Treatments receiving urea mineral molasses block had significantly higher concentration of TVFA, which implicates higher availability of fermentable energy coming from molasses (p <0.05). Effects of diet and monensin on plasma glucose concentration were significant, as treatment 4 had highest and treatment 1 had lowest plasma glucose concentrations (p <0.05). Urea mineral molasses block without monensin significantly increased plasma urea concentration but monensin decreased it (p <0.05). This shows that urea used in urea mineral molasses block increased ammonia concentration in the rumen and consequently increased plasma urea concentration. But monensin may have increased efficiency of ammonia used by rumen microorganisms therefore decreased plasma urea concentration.
Conclusion: Overall results showed that urea mineral molasses block improves efficiency of fermentable energy and nitrogen, dry matter and crude protein digestibility and nitrogen retention in lambs. So it can be concluded that urea mineral molasses block may be used to improve performance of growing male lambs.
