An in vivo and in vitro evaluation of feed potentials of leaves of condensed tannin rich tree (Albizia gummifera, (J.F. Gmel.) C.A.SM.)

Abstract

The objectives were to evaluate the effect of dietary inclusion of leaves of the condensed tannin-rich plant, Albizia gummifera (AG), in grass-based hay with or without polyethylene glycol (PEG) on nutrient utilization, growth performance in ram lambs and assess the correlation between CP and some selected in vivo and in vitro nutritive value parameters. A 7-days digestibility and 90-day feed intake and weight gain trials were conducted using lambs with an initial body weight (BW) of 24.50±0.02kg (mean±SE). The experiment was arranged with three treatments and eight animals per treatment in a completely randomized design. The dietary treatments consisted of grass based-hay (T1, control), daily supplementation of lambs with the AG at 30% of control diet + control diet (T2), and T2 + PEG (T3; 40g PEG: 1kg AG on DM basis per head). The lambs were individually fed at 3% of their live body weight and had free access to clean drinking water and mineralized salt licks. Apparent digestibility coefficients were determined for dry matter (DM), crude protein (CP), crude fat (EE), neutral detergent fiber (NDF), and acid detergent fiber (ADF). A gas production test was performed after 2, 4, 6, 8, 12, 24, 32, 48, 58, 72 and 96 h of incubation. Nutrient intake was higher in lambs supplemented with PEG followed by T2 as compared to the T1 (p<0.001). A loss in body weight was observed in the control group. The average daily body weight gain and apparent digestibility of all the chemical nutrients were significantly higher for T3 and T2 as compared to T1 (p<0.001). The highest and lowest weights of carcass parameters were recorded for PEG supplemented and control groups, respectively (p<0.05). The PEG supplementation had also a significant effect on the cumulative gas production(GP), organic matter digestibility (OMD), short chain fatty acid(SCFA) and ME content of diets (p<0.001). The highest (12.00 MJ/kg) and lowest ME contents (8.20 MJ/kg) of feedstuffs were recorded for T3 and T1, respectively (p<0.001). CP content was positively correlated with IVGP (r=0.71), IVOMD(r=0.72) and ME(r=0.87) contents of feedstuffs (p<0.05). The improvement in GP, OMD, SCFA and ME with PEG supplementation emphasizes the negative effect of CTs on digestibility. Feeding local grass hay would be inadequate as the sole source of nutrients for sheep. Therefore, 30% AG or 30% AG + PEG supplementation could maintain the optimum utilization of the grass based hays and resulted in better feed intake, digestibility and carcass parameters.