Nutritional evaluation of three local barley varieties and the impact of dietary enzyme on their apparent metabolizable energy

Two experiments were conducted to determine the true metabolizable energy corrected to zero nitrogen balance (TMEsub(n)) and true amino acid availability (TAAA) of three, local barley varieties, two-row Litani (Lsub(2)), two-row Pamir-35 (Psub(2)), and six-row Rihan-03 (Rsub(6)) and to study the effect of enzyme supplementation on their apparent metabolizable energy corrected to zero nitrogen balance (AMEsub(n)). Forty grams of glucose, corn, or barley variety grains was precision intubated to eight individually caged Babcock B 380 roosters. The TMEsub(n) of Lsub(2), Psub(2), and Rsub(6) (3224, 3419, and 3253 kcal/kg, on dry matter basis (DM), respectively) was lower than that of corn (P0.05). A11 the TAAA values in Psub(2) and that of methionine, cystine, lysine, threonine, proline, and valine in Lsub(2) and Rsub(6) were comparable with that of corn. Again, compared to corn, all other TAAA values in Lsub(2) and Rsub(6) were significantly lower, except for serine, glutamic acid, and isoleucine in Rsub(6). In the AMEsub(n) experiment, a reference diet containing 55% glucose and diets containing 50% corn or Lsub(2), Psub(2), and Rsub(6) at the expense of glucose, supplemented with either 0 or 0.1% enzyme, were each fed in 4 replicates (cages) to 4 birds/cage for 4 d, during which total excreta were collected at 48 and 96 h. Enzyme supplementation resulted in an AMEsub(n) improvement of 4.33, 11.5, and 17.2% for Lsub(2), Psub(2), and Rsub(6), respectively with an average AMEsub(n) of 3243 kcal/kg DM. In conclusion, TAAA in Psub(2) was similar to corn whereas that of some amino acids such as arginine and leucine were lower in Lsub(2) and Rsub(6). Enzyme supplementation to barley diets resulted in an average AMEsub(n) improvement of 11%. The current findings can assist and encourage poultry producers in formulating least cost rations containing local barley varieties.