Exploring Feeding Potential of Stovers from Novel Sorghum (Sorghum bicolor L.) Cultivars by In vitro Fermentation Pattern, Gas Production, Microbial Abundance and Ruminal Enzyme Production in Buffalo

Background: Crop residues play a central role in ruminant's diet in developing countries. Due to low in nutritional quality, there is limitation in ruminant production through feeding of these residues. Therefore, production of quality crop residues through plant breeding programme without conceding grain yield is of prime importance. The present experiment envisaged the feeding value of stovers from three different novel sorghum (Sorghum bicolor L.) cultivars by in vitro fermentation pattern, gas production, microbial abundance and ruminal enzyme production in buffalo. Methods: Stovers from three different genotypes of sorghum cultivars viz. normal sorghum (CSV-27), brown midrib (bmr) sorghum (SPV-2018) and sweet sorghum (CSH 22SS) were analyzed for proximate principles and fibre fractions. Each stover sample was incubated (200 +/- 5 mg) with 30 ml buffered rumen fluid in 100 ml calibrated glass syringes at 39 degrees C for 24 h following in vitro gas production system using rumen liquor from Murrah buffaloes. The gas production in each syringe was recorded during incubation at 4, 8, 12, 18 and 24 h intervals. Incubations were terminated at 24 h and methane concentration in the head space gas from syringes incubated with each stover sample was analyzed. Supernatant of each syringe contents was analyzed for volatile fatty acids (VFA) estimation. Truly degradable dry matter (TDDM) was determined and microbial biomass production (MBP) and portioning factor (PF) was calculated. Ruminal fibrolytic enzyme production and microbial abundance in each syringe content was estimated. Result: The stover of bmr sorghum showed highest organic matter, followed by normal sorghum and lowest in sweet sorghum. The neural detergent fibre (NDF) ranges between 69.22 to 74.65%, with highest in bmr sorghum and lowest in sweet sorghum. The stover sample of bmr sorghum contained lowest (P<0.05) acid detergent fibre (ADF) among the three cultivars examined, which resulted with highest (P<0.05) hemicellulose (37.72%) content. Lowest acid detergent lignin (ADL) was found in stovers of bmr cultivar (1.27%) and highest in sweet sorghum (8.36%). The fermentation pattern of bmr sorghum stovers exhibited higher (P<0.05) total gas production, dry matter degradability, VFA production, ruminal enzymes (CMCase, xylanase, acetyl esterase) and abundance of total ruminal bacterial population than normal and sweet sorghum stovers. Therefore, this study establishes the enhanced feeding value of stovers from bmr sorghum cultivar compared to normal and sweet sorghum cultivars for ruminant production.