اثرات استفاده از پیت و باگاس فرآوری شده با آمونیاک بر ترکیب شیمیایی، قابلیت هضم، فراسنجه های تولید گاز و عملکرد گوساله‌های پرواری

Background and objectives: As the population increases, Food supply is considered as the biggest global crisis. Proper feeding with the cheapest price and the highest productivity is the most important factor in the economy of livestock breeding. The main limitation of agricultural residues and by-products in livestock feeding is the low protein content and digestibility due to the presence of complex lignocellulosic compounds in them, which limits the use of nutrients and their energy by livestock. Therefore, proper processing and utilization of these residues in ruminants feeding is essential to improve livestock production. Including sugarcane by-products is the pulp remaining from extraction and sugar extraction, which is known as peat and bagasse. This by-product has a low nutritional value and is difficult to store due to relatively high humidity. The conducted studies have shown that by using various processing methods, it can be enriched and in addition to raising the nutritional value, can also be preserved. So, this study was carried out in order to localize and develop the method of ammoniating the sugarcane factory by-products (bagasse and peat) with anhydrous ammonia (ammonia gas) in two stages.
Materials and methods: At first, sugarcane peat and bagasse were ammoniated by using 3% by weight of ammonia gas and moisture to at least 20%. Ammonia gas injection was done using pressurized capsule, connection hose and required connections inside the stack. The time required for ammoniated bagasse processing was considered about one month. Analysis of the chemical composition of the processed and original peat and bagasse samples was performed and the digestibility of dry matter and organic matter was determined by using the two-stage digestion method of Tilley and Terry, and the metabolizable energy of the samples was determined by the test gas method. Then 30 fattening calves with an average weight of 242.53 ± 1.62 were divided into two groups. In the control and experimental groups were used ordinary peat and bagasse and ammoniated bagasse, respectively. Dry matter intake, daily weight gain and feed conversion ratio were compared between two groups.
Results: Ammonization of peat and bagasse increased crude protein content from 2.40% to 6.84% in ammoniated bagasse. The values of neutral detergent fibers, acid detergent fibers and hemicellulose decreased in ammoniated peat and bagasse (from 83.6 to 80.6 percent, from 53 to 51.2 percent, and from 30.6 to 29.40 percent, respectively). Ammonization of peat and bagasse improved the digestibility of dry matter (from 31.87 to 51.5%) and organic matter (from 31.34 to 51.48%). Replacing of ammoniated peat and bagasse in the fattening calves diets increased the daily dry matter intake and improved daily weight gain and average weight at the end of the period, and decreased food conversion ratio. Ammonization increased gas production and digestible organic matter content of bagasse (about 6%) compared to ordinary bagasse and subsequently, the amount of metabolizable energy increased from 4.26 to 5.11 MJ/kg DM in ammoniated bagasse. The daily weight gain and the average final weight of calves in the ammoniated sugarcane bagasse group were significantly higher than the unprocessed sugarcane bagasse group (1.437 versus 1.390 kg and 586.21 versus 558.06 kg, respectively).
Conclusion: Ammonization sugarcane by-products with ammonia gas is a simple and effective way to process and increase the nutritional value of these wastes, So, with this processing method, the amount of crude protein and digestibility of these wastes can be improved to a desirable extent. Using ammoniated peat and bagasse in the diet of fattening calves caused an increase in daily dry matter intake in the entire period, improvement in daily weight gain, average final weight of animals and reduction