Replacement of soybean meal with processed karanj (Pongamia glabra) cake on the balances of karanjin and nutrients, as well as microbial protein synthesis in growing lamb

An experiment was conducted to study effects of feeding processed karanj (Pongamia glabra) cake on digestibility, nutrient balances, karanjin balance and its effects on microbial crude protein (CP) synthesis. Twenty-four male lambs with a body weight of 12.9 ± 0.15 kg and aged 3.5 ± 0.79 months were equally divided into four groups and allotted to a soybean meal (SBM) based control (CON), or one of three concentrate mixtures containing processed solvent extracted karanj cake (SKC), water washed (WW), 25 g/kg lime (LM) and 4 g/kg binder (BN) treated SKC replacing 0.50 of the SBM in the CON. Respective concentrate mixtures were fed with ad libitum oat (Avena sativa) straw. A metabolism trial was conducted after 90 days and balances of nutrients and karanjin were determined. Intake of all the nutrients was lower (P<0.01) in karanj cake based diets. Intake of dry matter and CP was lower (P<0.01) in all karanj diets versus the control, but digestibility of nutrients was unaffected. Retention of N was lowest (P<0.01) in BN. Lambs fed the WW diet retained more (P<0.01) Ca (g/d) than the control, and retention of P was lower (P<0.01) in karanj cake based diets. Among the SKC fed groups, intake of karanjin was higher (P<0.05) in WW and LM, but lowest in BN. The group fed BN retained less (P<0.01) karanjin than WW and LM. Excretion of purine derivatives (PD) (mmol/d) did not differ among treatments. Excretion of creatinine was higher (P<0.01) in LM and BN diets than in the control. Synthesis of microbial CP was also similar among diets. Feeding of processed SKC containing concentrate mixtures to lambs lowered retention of N and Ca in LM and BN, while higher karanjin was retained in the WW and LM diets. Feeding of processed karanj influenced the balance of N, Ca, P and karanjin, while it had no effect on the microbial protein synthesis.