Fermentation kinetics of stems of sorghum and millet genotypes

Zerbini, E. and Sharma, A. and Rattunde, H.F.W. and Groot, J.C.J. (1999) Fermentation kinetics of stems of sorghum and millet genotypes. Animal Feed Science and Technology, 81 (1-2). pp. 17-34.

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Abstract

Gas production profiles were obtained from in vitro fermentation of stems of 6 genotypes of sorghum and [pearl] millet grown at ICRISAT, India. The ranking of sorghum and millet genotypes by cumulative gas production was consistent throughout the 96 h fermentation period. However, differences were proportionally greater during the initial 3 and 6 h of fermentation. The multiphase model described by Groot et al. [Animal Feed Science Technology (1996) 64, 77-89] was used to fit the in vitro fermentation gas observations of the substrates, and fermentation kinetics parameters were calculated using the fitted model. The final estimates of the model parameters (A, B, C) were stable, showing no dependence on the starting values of the model parameters. However, in millet stems, the C parameter showed a tendency to converge near unity. In both sorghum and millet, the asymptotic gas of the first phase (A1) was negatively correlated with NDF (r = -0.82, P<0.05; r = -0.80, P<0.05, respectively) and lignin (r = -0.86, P<0.05; r = -0.95, P<0.01, respectively). The estimated maximum fractional rate of substrate digestion in the second phase (Rm2) showed a strong inverse relationship with lignin (r = -0.93, P<0.01) in millet but not in sorghum. On the other hand, the time at which the rate of fermentation reached its maximum in phase 1 (tmax1) was negatively correlated with ADF and lignin (r = -0.88, P<0.05 and r = -0.87, P<0.05, respectively) in sorghum, whereas in millet only tmax2 (phase 2) was negatively correlated with lignin (r = -0.88, P<0.05). Estimated differences in the contribution from the different phases to similar cumulative gas at 48 h in stems of different sorghum genotypes indicated the need to complement measurements of total gas production with selected kinetics parameters

Item Type: Article
Author Affiliation: International Livestock Research Institute Asia Region, c/o ICRISAT, Patancheru 502 324, Andhra Pradesh, India
Subjects: Crop Improvement
Crop Improvement > Genetics
Divisions: Sorghum
Millet
Depositing User: Mr B Krishnamurthy
Date Deposited: 11 Jan 2011 18:28
Last Modified: 11 Jan 2011 18:28
Official URL: http://dx.doi.org/10.1016/S0377-8401(99)00081-4
URI: http://eprints.icrisat.ac.in/id/eprint/1335

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