Document Type : Research Articles
Authors
Department of Animal Science, Faculty of Agriculture, Ilam University, Ilam, Iran
Abstract
Introduction: Ruminants, among domesticated herbivorous animals, play a major role in providing food resources and producing essential nutrients required by humans, thereby contributing to human health. Nutrition is a key factor influencing livestock performance and production efficiency, accounting for almost two-thirds of the total costs of raising domestic animals in various livestock farming units. Currently, due to the increase in livestock population and the decrease in precipitation, we are facing a decrease in the production of common food resources, and the need to provide cheap fodder resources highlights the importance of fodder resources used in livestock nutrition. Sugarcane is a perennial plant that grows in tropical and subtropical regions, including Khuzestan Province. Its by‑products, such as bagasse, can be used in animal feed. Due to the presence of lignin, cellulose, and hemicellulose, as well as the strong bonds found in woody materials like bagasse, its digestion in the digestive tract is less affected. A study is needed to investigate the processing of bagasse with urea and molasses and their interaction between the nutritional value of bagasse. One of the factors that may affect the chemical processing of bagasse is the duration of processing, which has not yet been investigated in this field. Therefore, this study was conducted to evaluate the effects of diets containing sugarcane bagasse (SB) treated with urea and molasses for 30 or 45 days on ruminal fermentation parameters and the in vitro degradability of dry matter (DM) and organic matter (OM).
Materials and Methods: Sugarcane bagasse (SB) samples were obtained from a sugarcane factory located in Khuzestan Province. SB samples were oven-dried, ground in a mill, and passed through a 1 mm sieve. The SB samples were mixed with 5% urea and 10% molasses solution and stored under anaerobic conditions for 30 or 45 d. Experimental diets included 1) diet containing untreated SB and stored for 30 d; 2) diet containing SB treated with 10% molasses solution and stored for 30 d; 3) diet containing SB treated with 5% urea solution and stored for 30 d; 4) diet containing SB treated with 10% molasses and 5% urea solution and stored for 30 d; 5) diet containing untreated SB and stored for 45 d; 6) diet containing SB treated with 10% molasses and stored for 45 d; 7) diet containing SB treated with 5% urea solution and stored for 45 d and 8) diet containing SB treated with 10% molasses and 5% urea solution and stored for 45 d. After 30 or 45 d, the samples were removed from the nylon bags, air-dried for 5 d, and stored until further analysis. The experimental diets were formulated using NRC (2007) software according to the nutrient requirements of ewes. Then, the chemical compositions, gas production at 24 and 96 h, DM and OM degradability, and methane gas production of the experimental diets were measured. The experiment was conducted under a 4×2 factorial randomized complete block design using the General Linear Model (GLM) procedure of SAS.
Results and Discussion: The lowest DM and NDF contents and the highest crude protein content were observed in the diet containing bagasse treated with 10% molasses and 5% urea and ensiled for 30 or 45 d (P<0.05). Among the processing methods, treatment with 10% molasses and 5% urea solution followed by 30 or 45 d of ensiling had the greatest effect on increasing cumulative gas production at 24 and 96 h, gas production potential (A), and DM and OM degradability (P<0.05). The lowest cumulative gas production at 96 h was observed in the untreated bagasse ensiled for 30 d (P<0.05). The shortest lag time was found in diet containing bagasse treated with 5% urea solution and ensiled for 30 or 45 d, as well as those treated with 10% molasses and 5% urea solution and ensiled for 30 or 45 d, whereas the longest lag time belonged to the control diets (P<0.05). Methane production, partitioning factor, and efficiency of microbial mass production were not affected by experimental diets (P>0.05). Urea and molasses solutions, by breaking down the structure of feed fibers, reduce the lignin content of the feed and enhance the access of rumen microorganisms to the lower layers of lignin, cellulose, and hemicellulose in the feed. As a result, they increase fermentation and gas production, as well as improve the degradability of DM or OM.
Conclusion: Overall, chemical treatments, compared to the control treatments, effectively altered the chemical composition of bagasse, increased the gas production rate, and enhanced DM and OM degradability. Among the different processing methods, treating bagasse with 10% molasses and 5% urea solution followed by 45 d of ensiling resulted in the highest gas production rate (A), and DM and OM degradability. Therefore, the combination of 10% molasses and 5% urea solution is considered a more suitable processing method for bagasse.
Keywords
Subjects
