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.
