مطالعه تاثیر عمل آوری با بخار آب تحت فشار و آب اکسیژنه قلیایی بر ارزش تغذیه‌ای سرشاخه نیشکر برای بره‌های پرواری

Introduction: A significant portion of livestock feed resources are roughage and fibrous in Iran, which is low in protein, minerals, and digestible energy; however, if treated by some methods, has the potential to be used as an energy source in livestock diets (Adesogan et al. 2019). There are 10 sugarcane development companies in Khuzestan province, which have 127,000 hectares under sugarcane cultivation and the area under sugarcane cultivation is 100,000 hectares per year (FAOSTAT 2013). Sugarcane is harvested in two ways: black (burning) and green (harvesting with a harvester). About 15 to 25 percent of the weight of sugarcane includes leaves and branches named sugarcane top, so the green harvesting produces about 20000 kg of wet biomass per hectare (Moradi et al. 2019). Due to the area under sugarcane cultivation in the Khuzestan province, and its 50% humidity, about two million tons of sugarcane top is produced each year. During harvesting, the sugarcane residues remain on the ground and cause special problems for the maintenance operation of the sugarcane on the field, so the residue is burned in two stages before and after harvesting, and it pollutes the environment, especially the air (Kingston et al. 2005). If the sugarcane top residues treated, due to breakdown of lignocellulose structure and degradation of lignin, cased to the increased access of ruminal microorganisms to lignosullose materials, so instead of burning, they can be used as fodder sources in animal feeding (Karp et al. 2013). Therefore, the aim of present experiment was conducted to evaluate the effects of steam and alkaline hydrogen peroxide treatment to improve the nutritional value of sugarcane top for fattening lambs.
Material and method: The present experiment was performed in Agricultural Sciences and Natural Resources University of Khuzestan. The sugarcane top used in the present experiment was from variety of CP73 and CP57 harvested from Imam Khomeini agro-industry company of Shushtar. After the sugarcane was harvested, it was dried and chopped into 2 to 3 cm long with a chopper and transferred to the Shoaibiyeh Livestock Feed Company for steam treatment. Steam was conducted at 184ᵒC for 4 minutes; the equal pressure was 16 to 18 atm. (average 17 atm.). The sugarcane top was treated using a solution of 1% hydrogen peroxide, which pH was adjusted to 11.5 using a solution of sodium hydroxide (alkaline hydrogen peroxide). Twenty-four Arabi male lambs with average live weight of 30.4 ± 5 kg were used in a completely randomized design with 3 treatments and 8 replicates for a period of 70 days. Experimental treatments were: 1- control (untreated Sugarcane top), 2- diet containing steam treated Sugarcane top, and 3- diet containing steam and alkaline hydrogen peroxide treated sugarcane top.
Results and discussion: Treatment with steam and alkaline hydrogen peroxide significantly reduced the percentage of NDF, ADF, crude fiber, lignin, and increased the significance of the gross energy of sugarcane (P <0.05), but had no effect on crude protein. In consistent with the results of the present experiment, other researchers also reported a decrease in dry matter, NDF, and ADF by applying water vapor under pressure. The decrease of these nutrients has been attributed to the fragmentation or hydrolysis of all or part of the hemicellulose. In compared to control, average feed intake, digestibility of nutrients, final weight, average daily gain, feed efficiency of lambs, rumen propionate and total volatile fatty acids, and blood glucose were increased with feeding of treated sugarcane top, and treatment 3 shown the best results (P<0.05). The components of the experimental diets are the same, and the only difference was in the type of treatments. Therefore, perhaps the reason for the increase in feed consumption in treatments containing sugarcane top treated with steam or steam and alkaline hydrogen peroxide is to improve its digestibility. Increasing digestibility will cause the material to pass through the rumen faster and thus animals consume more feed. The concentration of alanine transaminase was decreased, because of treatment of sugarcane top (P<0.05). The concentration of rumen ammonia nitrogen and pH, blood aspartate transaminase, and carcass traits were not affected by the treatments. Therefore, treatment by steam and alkaline hydrogen peroxide caused to improve the nutritional value of sugarcane top, and their combined use (third treatment) showed better results.

Results and discussion: Treatment with steam and alkaline hydrogen peroxide significantly reduced the percentage of NDF, ADF, crude fiber, lignin, and increased the significance of the gross energy of sugarcane (P <0.05), but had no effect on crude protein. In consistent with the results of the present experiment, other researchers also reported a decrease in dry matter, NDF, and ADF by applying water vapor under pressure. The decrease of these nutrients has been attributed to the fragmentation or hydrolysis of all or part of the hemicellulose. In compared to control, average feed intake, digestibility of nutrients, final weight, average daily gain, feed efficiency of lambs, rumen propionate and total volatile fatty acids, and blood glucose were increased with feeding of treated sugarcane top, and treatment 3 shown the best results (P<0.05). The components of the experimental diets are the same, and the only difference was in the type of treatments. Therefore, perhaps the reason for the increase in feed consumption in treatments containing sugarcane top treated with steam or steam and alkaline hydrogen peroxide is to improve its digestibility. Increasing digestibility will cause the material to pass through the rumen faster and thus animals consume more feed. The concentration of alanine transaminase was decreased, because of treatment of sugarcane top (P<0.05). The concentration of rumen ammonia nitrogen and pH, blood aspartate transaminase, and carcass traits were not affected by the treatments. Therefore, treatment by steam and alkaline hydrogen peroxide caused to improve the nutritional value of sugarcane top, and their combined use (third treatment) showed better results.