Abstract

The objective of the work described here was to investigate the effect of two levels of Nigella sativa (0 and 7.5 g NS / kg DM) supplementation to rations of Karadi lambs fed three levels of rumen degradable nitrogen (1, 1.3 and 1.6 g RDN / MJ of ME) on carcass characteristics, using 2 x 3 factorial experiment. Twenty four individual Karadi male lambs were used (four lambs for each treatment). They were weighing approximately 30 kg live weight and 7 months old. The diets were formulated to be given at 40% NaOH-treated barley straw DM to 60% concentrates DM. At the end of feeding trial, all the lambs were slaughtered after over night with feeding straw. Live weight gain was improved (P < 0.05) in lambs fed diets supplemented with NS as compared with those lambs fed diet without NS. However, live weight gain was not affected by levels of RDN. Changes in slaughter weight, Killing out proportion, leg cuts tissue, the wholesale cuts weight and fat-tail weight were not significantly affected by both NS supplementation and levels of RDN. However, the heavier slaughter weights, cold carcass and fat tail weights were associated with lambs fed highest level of RDN supplemented with NS (P < 0.05). Moreover, there is a linear increase in fat-tail weight associated with lambs fed increasing levels of RDN supplemented with NS.

Key word: Karadi, Lambs, Carcass characteristics, Rumen degradable nitrogen,Nigella Sativa.

Abbreviation

RDN, Rumen degradable nitrogen; NS, Nigella sativa; SBM,soybean meal; FTSBM, formaldehyde- treated soybean meal; UDN, undegradable nitrogen; CRD, completely randomized design; FCR, feed conversion ratio; LWG,live weight gain; CCW, cold carcass weight; TN, total nitrogen; MJ, metabolizable energy.