Determination of Nutritional Value of Acroptilon Repens At Different Phonological Stages Compared To Alfalfa Hay and Wheat Straw in Laboratory Conditions

This research was conducted in order to determine chemical composition, gas production parameters, in vitro digestibility and ruminal degradability of Acroptilon repens at different phonological stages (vegetative, flowering and seeding) and its comparison with alfalfa hay and wheat straw in Completely Randomized Design. For this purpose, Acroptilon repens was prepared in three stages of growth from Quchan pastures. The chemical composition of the samples was determined using the standard methods. The gas production test was used to estimate the gas production parameters of samples. In vitro digestibility of samples was determined by the batch culture method. Ruminal degradability trial was carried out by the nylon bag technique. The amount of Ash, crude protein (CP), Ether extract (EE), non- fiber carbohydrates (NFC) and neutral detergent soluble (NDS) at vegetative stage of Acroptilon repens were higher than wheat straw. At this phonological stage, neutral detergent fiber (NDF) and acid detergent fiber (ADF) were lower than wheat straw and alfalfa hay (p<0.05). The highest and lowest values of gas production potential were related to Acroptilon repens at flowering stage and wheat straw respectively (p<0.05). Estimated parameters including metabolizable energy (ME) and organic matter digestibility (OMD) at vegetative and seeding stages of Acroptilon repens were higher than wheat straw (p<0.05), but had no significant difference with alfalfa hay. The amount of dry matter digestibility of Acroptilon repens at vegetative and seeding stages did not differ with alfalfa hay and wheat straw, but was lower at flowering stage (p<0.05). OMD, microbial biomass (MB) and its efficiency (EMB) at vegetative stage of Acroptilon repens was higher than other treatments (p<0.05). Washout fraction (a) and potentially degradable fraction (b) of Acroptilon repens in all phonological stages was higher than alfalfa hay and wheat straw, meanwhile degradability of this plant at vegetative stage was higher than other treatments (p<0.05). Based on the results of this study and considering the chemical composition and fermentation parameters, Acroptilon repens at vegetative stage had higher nutritional value.