Effect of cyanide-degrading bacteria inoculation on performance, rumen fermentation characteristics of sheep fed bitter cassava (Manihot esculenta Crantz) leaf meal

Abstract

This study aimed to evaluate the performance and fermentation characteristics in the rumen of Garut grade sheep fed bitter cassava (M. esculenta Crantz) leaf meal (BCL) supplemented with cyanide-degrading bacteria (CDB). Fifteen sheep (12 mo with average weight of 18.8 ± 1.02 kg) were placed in individual cages provided experimental diets and free access to water. A completely randomized design applying five treatments and three replicates was used. The treatments were T1 [40% Napier grass:60% concentrate (Con)], T2 [40% Napier grass:45% concentrate: 15% BCL (BCL15)], T3 (BCL15 + CDB), T4 [40% Napier grass:30% concentrate:30% BCL (BCL30)], and T5 (BCL30 + CDB). The data were subjected to analysis of variance and significant differences among treatments were further analyzed using Tukey test. The data of different levels of BCL and CDB inoculation were contrasted using orthogonal contrast test. Feeding BCL 15% and 30% to substitute concentrate ration did not affect feed intake and nutrient digestibility but decreased (P < 0.05) the total volatile fatty acid (VFA), concentration of NH_3, feed efficiency and body weight gain of sheep. Inoculation of CDB to the sheep fed 15% and 30% BCL did not affect total VFA and NH₃ concentration, but it increased (P < 0.05) body weight and feed efficiency. The methane estimation were similar among treatments. In conclusion, CDB inoculation could detoxify cyanide in BCL and enhanced rumen fermentation profile when BCL 15% and 30%.