Indian J Dairy Sci 73(3): 246-249 246 RESEARCH ARTICLE Effect of different levels of sodium sesquicarbonate on in vitro rumen fermentation parameters Hunny Sharma 1 , Veena Mani 1 , Sachin Kumar 1 , Srobana Sarkar 2 and Hujaz Tariq 3 1 Animal Nutrition Division, National Dairy Research Institute, Karnal, 132 001, Haryana, India 2 Animal Nutrition Division, Central Sheep and Wool Research Institute, Avikanagar, 304 501, Rajasthan, India 3 De Heus India, Rajpura, 140 401, Punjab, India Hunny Sharma () Animal Nutrition Division National Dairy Research Institute, Karnal, 132 001, Haryana, India Email: vet657@gmail.com; Tel: +91-9149964783 Received: 05 February 2020 / Accepted: 31 March 2020 / Published online: 12 July 2020 Indian Dairy Association (India) 2020 © Abstract: This experiment was conducted to study the effects of sodium sesquicarbonate on in vitro rumen fermentation parameters. Sodium sesquicarbonate (NaSc) was added at different levels (0.5, 1, 1.5, 2, 2.5 and 3%) to the substrates having concentrate: roughage ratio (concentrate: sugargraze fodder) of 50:50 and 60:40. There was no significant effect of addition of sodium sesquicarbonate (upto 3%) on in vitro DM digestibility and organic matter digestibility in different treatments. Average value of NH 3 -N, IVFA, MBP, PF, molar proportion of acetate, propionate and butyrate also remained unaffected due to NaSc supplementation. Keywords: Buffer, In vitro, Rumen fermentation, Sodium sesquicarbonate Introduction There is decline in milk yield in many dairy herds which appear to be temporarily increased by overfeeding of grains (Kmicikewyez and Heinrichs, 2014; Abdela, 2016) and such diets may potentially exacerbate subacute acidosis which represents one of the most important metabolic disorders that affects rumen fermentation resulting in decrease in DMI, milk yield, and milk fat content, animal welfare and farm profitability (Morgante et al. 2007; Mao et al. 2017). Such rations also tend to support less rumination which reduces the production of salivary bicarbonate. Subacute ruminal acidosis is characterized by low ruminal pH (5.8-5.0) and an alteration in ruminal biohydrogenation of dietary polyunsaturated fatty acids (Bauman and Griinari, 2003; Plaizier et al. 2008). Different approaches have been made for improving the ruminant production by searching the alternatives for stabilizing the rumen pH to minimize the occurrence of rumen acidosis and related disorders (Owens and Basalan, 2016). Rumen buffer could be one such alternative considering facts that addition of dietary buffers to control rumen pH can be justified if bunk management and nutritional factors cause low pH (Kang and Wanapat, 2013). Buffers can neutralize the excessive acidity due to increased production of volatile fatty acids but the effects depend upon type of buffer, dose and type of animal in which it is supplemented (Sen et al. 2006). Bicarbonates are commonly used as exogenous buffer as their dissociation constant (pka =6.25) is close to normal rumen pH thus possessing high acid consuming capacity (Marden et al. 2008) and thus prevent further depression in pH (Humer et al. 2018). Sodium bicarbonate increases rumen pH, produces a more desirable rumen fermentation and increases rumen fluid outflow. Dietary supplementation of sodium sesquicarbonate could be one of the alternative as it is a mixture of sodium bicarbonate and sodium carbonate and is naturally occuring an alkalizing agent. The pH of a one percent sodium sesquicarbonate solution is 9.9 as compared to sodium bicarbonate which is 8.4 thus expected to have better potential for buffering action besides being cost effective. Therefore, the present experiment was conducted to study the effects of sodium sesquicarbonate on in vitro rumen fermentation parameters. Materials and Methods Substrate composition, treatments and parameters estimated Sugargraze (moderately draught tolerant sweet sorghum hybrid) fodder and concentrate mixture were dried in hot air oven at 60°C for 48 h and ground using a hammer mill to pass thtrough 1 mm sieve. The substrate was prepared by mixing concentrate mixture and sugargraze fodder in the ratio of 50:50 and 60:40. Sodium sesquicarbonate was added in treatment groups at different levels viz. 0.5, 1.0, 1.5, 2.0, 2.5 and 3.0% of substrate whereas the control group comprised of only substrate. Proximate principles and fibre https://doi.org/10.33785/IJDS.2020.v73i03.009