Effect of feeding castor seed cake based diets on growth, nutrient utilization, immune response and carcass traits in lambs

Abstract

An experiment was conducted to study the effect of utilizing Castor (Ricinus communis) Seed Cake (CSC) (30-45% Crude Protein; CP) as sole protein supplement, replacing groundnut cake (GNC) on growth performance, nutrient utilization, immune response and carcass traits in lambs. Two isonitrogenous and isocaloric complete diets (10.5% CP and 58% TDN) were formulated with 13% GNC and 10% CSC and fed ad libitum to 14 Nellore male lambs (27.54+1.154 kg), divided at random into two groups of seven animals for a period of 150 days. The lambs in both groups grew linearly with average daily gain of 75.33 and 74.28 g, respectively with no significant difference. Inclusion of CSC did not affect the Dry Matter (DM) and CP intake and was comparable to that of control lambs but the intake of metabolizable energy was lower (p<0.01) in CSC fed lambs. The lambs fed either GNC or CSC utilized DM and nutrients with similar efficiency. Inclusion of CSC in complete diets of lambs did not affect the nutrients digestibility, balances of nitrogen, calcium and phosphorus, hematological (haemoglobin, total erythrocyte and leucocyte counts) and biochemical constituents (total protein, albumin, globulin and creatinine) except for higher (p<0.01) digestibility of crude fibre in CSC fed lambs compared to GNC feeding. While, the antibody titers against heat killed Brucella abortus and chicken RBC antigens assessed at 75 day of feeding and the skin indurations against PHA-P mitogen, assayed at 150 day of feeding was lower (p<0.01) with CSC feeding. The carcass characteristics (dressing percentage, proportion of meat, bone and fat, proportion of edible and non-edibles, whole sale cuts, organ weights and chemical composition of Longissimus dorsi muscle) were not influenced by inclusion of CSC as sole protein supplement. Histopathological lesions observed were mild to moderate areas of necrosis, congested blood vessels with increased kuffer cell activity in liver, swollen kidney tubules with increase in mononuclear cell infiltration, decreased goblet cell activity and infiltration of neutrophils in intestines. The study suggested no adverse effect on the nutritional performance and carcass traits of lambs with inclusion of 10% CSC in complete diets but the immune response was depressed and lesions of pathological significance was observed in vital organs compared to GNC fed lambs.