Carbohydrate, protein fractions and energy contents of prominent Indian green fodders vis a vis their contribution in in vitro methane production on incubation in buffalo inoculums

Sultan Singh, BP Kushwaha*, P K Gupta**, S Bhattacharya***, S K Nag and A K Mishra

Indian Grassland and Fodder Research Institute, Jhansi India

Abstract

Green fodders viz. berseem (Trifolium alaxendrum), lucerne (Medicago sativa), groundnut leaves (GNL Arachis hypogea), oat (Avena sativa), sorghum (Sorghum bicolor), barley (Hordeum vulgare), napier grass (NG Pennesetum purpureus), guinea grass (GG Panicum maximum), sugarcane tops (ST Saccharum officinarum), Leucaena leucocephala (LL) and Grewia optiva (GO) leaves were evaluated for chemical attributes (proximate constituents, cell wall polysaccharide, protein and carbohydrate fractions), energy contents, IVDMD and in vitro CH4 production in buffalo inoculums. Protein was more in berseem, lucerne and LL (16-88-20.98) than grasses and cereal fodders, while cellulose contents were low in former than later fodders. NDIN and ADIN contents were lower in lucerne and berseem (16.28 &14.78) and (5.99 &7.39 %) and higher in ST, sorghum and grasses (61.74, 34.71 & 49.05) and (26.82, 18.53 & 10.92 %). Lignin bound protein (Pc) was higher in ST (26.82), sorghum (18.53) and GNL (16.57) compared to lower in lucerne (3.91) berseem (5.99) and barley (4.71 %). NSC were more in GNL (41.33), GO (36.78), LL (40.09) and lowest in NG (7.92) GG (7.65) and ST (11.75), while CC was more in LL (28.58) and Lucerne (24.52 %). CB1 was (P<0.05) more in LL (20.21), GO (22.24), GNL (15.36) and berseem (15.12 %).  Energy, DMI and IVDMD of fodders varied from 3.96-4.71 K cal/g, 1.61-3.98 % and 35.30-73.98 %, respectively.

CH4 % of total gas was higher from fermentation of berseem and  lucerne  (10.80 and 10.18 %) against lowest from NG and tree leaves (LL & GO) at 12 h of fermentation. At 24 h of fermentation CH4 (%) was higher from sorghum (14.89), barley (14.40) and berseem (13.81 %). Corresponding values of CH4 ml/g of roughage fermented was more from GO (17.48) and NL (15.47). CP, NDF and energy of green fodders were negatively associated with in vitro CH4 production, while OM was positively associated with CH4 production.  ADF, cellulose and digestibility were inversely related with CH4 production, while lignin was positively associated (r = 0.262). NDIN, ADIN and PB3 fractions of N were positively associated with in vitro CH4 production for green fodders (r = 0.464**, r = 0.457** and r = 0.342*). N fractions NPN and PA were negatively associated with CH4 production (r = -0.214 and r = 0.581**).  PB3 and PC fraction of N were positively correlated with CH4 production for green fodder (r = 0.342* and r = 0.666**).  CA, CB1 and CB2 fractions of carbohydrates were positively associated with in vitro CH4 production (r = 0.406**). Energy loss as CH4 tended to be more for oat (5.98 %) than barley (5.81%). NG and GG produced less CH4 (0.0252 and 0.0283) than sorghum (0.0306) and ST (0.0305 g/g DDM). GNL produced more CH4 (0.0352) than GO (0.0328) and LL (0.0276 g/g DDM). Energy loss as CH4 from NL, GO and LL leaves was 11.26, 10.37 and7.99 %, respectively.  CH4 production (g/Kg DMI) was lowest from ST (10.74) and higher from GNL 926.82), while CH4 production (g/Kg DDMI) was lower from oat (20.36), barley (21.26) and lucerne (20.43-21.32) and higher from GNL (35.21), GO (32.82) and ST (30.50). Proximate constituents and Carbohydrate fractions of green fodders were highly correlated with CH4 production (R2 = 0.835 and 0.805), while N fractions had moderate association (R2 =0.691).

*Network Project on Bhadawari, ** NPL, Delhi, *** Natcom Project Manaement Cell, Delhi