Effect of harvesting interval on biomass yield and chemical composition of taro (Colocasia esculenta (L.) Schott) for feeding pigs in Laos

Abstract

Cheap feedstuffs with acceptable protein content are needed for the improvement of pig performance in developing countries, and the utilization of traditional crops is one possible solution. Taro (Colocasia esculenta (L.) Schott) was grown for two seasons in Vientiane, Lao PDR, and was subjected to three harvesting frequency treatments. The treatments applied were harvesting leaves and petioles at intervals of 4 (H4), 6 (H6) and 24 (H24) weeks, respectively. The tubers were harvested at the last harvest occasion. Leaf, petiole and tuber dry matter (DM) yield, leaf proportion (DM basis) and chemical composition of the leaves and petioles were determined. Treatments H4 and H6 yielded significantly more leaf and petiole DM than treatment H24 in both years. Total leaf DM yield was 2146, 1654 and 364kgha−1 in 2007 and 1483, 1341 and 691kgha−1 in 2008 for treatments H4, H6 and H24, respectively. Tuber DM yield was not affected by the treatments and was on average 3667 and 2732kgha−1 in 2007 and 2008, respectively. Leaf proportion did not generally differ between treatments and was on average 52 and 62% in 2007 and 2008, respectively. The leaves contained between 160 and 260gkg DM−1 crude protein (CP) which was much higher than in the petioles. Although significant, the difference between treatments was small, which was due to the high rate of leaf turn-over (5 weeks). Ash content of the leaves was 112–145gkg DM−1, and crude fiber (CF) was a 173–206gkg DM−1. The total essential amino acid content of taro leaf ranged from 40 to 45g, 16gN−1. It is concluded that taro leaves are a potential protein feed resource for growing pigs, and that leaves can be harvested frequently with no detrimental effect on tuber yield.