Effect of Nutrient Synchrony on Ruminal Fermentation, Microbial Protein Synthesis and Nitrogen Balance in Sheep

[1] The nutrient synchrony is synchronization of ruminal fermentation rate of energy and nitrogen which is a method to increasing microbial protein synthesis, improving nitrogen efficiency, decreasing urinary nitrogen excretion and improving animal performance. Microbial protein production is important for ruminants. Current concepts of ruminant nutrition focus on optimizing ruminal microbial protein synthesis. Microbial yield in rumen depends largely on the supply of carbohydrates and nitrogen in the rumen. Balancing the rate of supply of nitrogen and energy yielding substrates to rumen microbes has been proposed in order to maximize the capture of rumen degradable protein and to optimize microbial growth rate and its efficiency. A more efficient capture of rumen degradable protein would reduce the requirement for expensive undegradable protein sources and also reduce the excretion of urinary nitrogen which case to environmental pollution and economical losses. Synchronization index expressed as the ratio between the hourly degradability of nitrogen with organic matter or carbohydrates in the rumen where the highest value for the synchrony index is 1.0. This research was done to evaluate the effect of synchronizing the rate of carbohydrate and crude protein ruminal fermentation on ruminal fermentation products, microbial protein synthesis, and nitrogen balance and blood parameters in sheep which were fed with similar components or structure high concentrate diets.

Chemical compositions and degradability parameters of crude protein and carbohydrate for alfalfa hay, wheat straw, barley grain, corn grain, sugar beet pulp, wheat bran and soybean meal were determined. Three diets were formulated for feedlot male lambs with same energy and metabolizable protein but containing different synchrony index 0.64, 0.78 and 0.92 which calculated by using degradation parameters of carbohydrate and crude protein of feeds from the diet. The effects of synchrony index of diets by 6 rumen-fistulated sheep with an average weight of 30.17±1.17 kg in metabolic cages were assigned in a duplicate 3×3 Latin square design (2×3 animals; 3 periods). Samplings were done in 3 periods (each period containing 14 days for adaptation and 5 days for sampling). Rumen fluid was collected for 5 consecutive days in the end of each period and ruminal fermentation parameters containing pH, NH3-N and volatile fatty acids were determined. Urine of sheep was collected end of each period for 5 days and microbial protein synthesis was estimated by measuring purine bases also nitrogen balance was calculated from the values of nitrogen consumption and excretion. Bleeding (19th trial day) were done from sheep and blood parameters such as glucose, albumin and blood urea nitrogen were determined.

There was no significant difference in ruminal pH among diets during fasting conditions or before feeding. Also there was no significant difference in ruminal pH between treatments at 3 or 6 hours after feed intake. With increasing synchrony index, ruminal NH3-N concentrate reduced especially at 1.5 and 3 hours after feed intake. Total volatile fatty acids highest at 3 hours after feed intake for diet had highest synchrony index. With increasing synchrony index, total volatile fatty acids concentration increased almost by 20 percent. Also the propionate concentrates increased not only before feeding but also at 3 hours after feeding. Total volatile fatty acids and propionate concentration showed a linear trend between diets at 3 hours after feeding. Purine bases such as allantoin, uric acid, xanthine and hypoxanthine, total purine derivatives excreted or absorbed also microbial protein synthesis not affected by experimental diets. With increasing synchrony index, total excreted nitrogen reduced but nitrogen retained and its efficiency increased. Blood parameters such as glucose, albumin and blood urea nitrogen not affected by treatments.

with increasing synchrony index of the diets, microbial protein synthesis did not increase but total volatile fatty acids concentration and retained nitrogen increased whereas ruminal NH3-N concentration and total excreted nitrogen decreased. However, increasing nutrient synchrony index in high concentrated diets did not show the expected desirable results such as increasing microbial protein synthesis however did not also show undesirable results such as animal health. Due to the beneficial effects as increasing in fermentation and decreasing nitrogen excretion or environmental pollution using the high synchrony index diets can be useful for feed formulation or providing the perfect mix of feed items to meet nutritional requirements of sheep.