Vol. 12, Special Issue 9 (2023)

Author(s):
Adire Chandrakanth, Ch. Harikrishna, DBV Ramana, A Sarat Chandra and M Venkateswarlu

Abstract:
A study was conducted to assess the impact of elevated carbon dioxide and temperature levels on the quality of groundnut haulms used as livestock feed. Groundnut crop was grown with recommended package of practices in carbon dioxide and temperature gradient chambers (CTGC) at four different environmental conditions, viz: chamber with ambient temperature and carbon dioxide with 27 ± 0.5 °C temp and 380 ± 25 ppm CO₂ (T₁; control), chamber with elevated temperature of 5 ± 0.5 °C higher than control (T₂; eTemp), chamber with elevated CO₂ concentration of 550 ± 50 ppm (T₃; eCO₂) and chamber with elevated CO₂ concentration of 550 ± 50 ppm with elevated temperature of 5 ± 0.5 °C, over control (T₄; eCO₂+eTemp). At harvest stage, representative groundnut plants from each chamber were collected, haulms were separated and screened for further laboratory analysis. In vitro dry matter digestibility (IVDMD) of haulms of groundnut crop grown under different CTGC chambers differed significantly (p<0.01). Highest IVDMD in groundnut haulms was found in the groundnut crop grown in ambient (T₁; control), whereas lowest under elevated temperature (T₂; eTemp) environmental conditions. Digestible energy (DE; MJ/kg) content in the haulms of groundnut crop grown under different CTGC chambers differed significantly (p<0.01). Highest DE was found in the haulms of groundnut crop grown in ambient (T₁; control) whereas lowest was found in elevated temperature (T₂; eTemp) conditions. Metabolizable energy (ME; MJ/kg) content varied significantly (p<0.01) and highest was found in the haulms of groundnut crop grown in ambient (T₁; control) whereas lowest under elevated temperature (T₂; eTemp) conditions. The cumulative in vitro gas production (IVGP; ml/g^-1DM) from groundnut haulms grown in different CTGC chambers also varied significantly (p<0.01). The highest cumulative IVGP was found in haulms of groundnut crop grown in elevated carbon dioxide (T₃; eCO₂), while the lowest was found in elevated temperature (T₂; eTemp) conditions. The study concludes that the in vitro dry matter digestibility of groundnut crop haulms grown in CTGC chambers indicated that elevated temperature could impact the dry matter digestibility compared to elevated carbon dioxide. Under elevated temperature conditions, the digestibility and energy content of groundnut haulms decreased due to increased lignification. The highest cumulative gas production was found in haulms of groundnut crop grown in elevated carbon dioxide, while elevated temperature had no significant effect on cumulative gas production, though higher temperatures were maintained in both the eTemp and eCO₂+eTemp chambers.