Efek suplementasi asam amino bercabang terhadap fermentabilitas dan kecernaan In vitro ransum berpakan serat sabut sawit

Abstract

Branched chain amino acids (BCAA) has been claimed to stimulate microbial growth in the rumen, hence and fiber digestion. Most of the works however, used Valine (Val), Leucine (Leu), or Isoleucine (Ile) as single supplement. It is known that the acids are antagonistic in the transfer into cells. What is the proper proportion of the acids has never been elucidated. This study tried to make use the ample supply of palm press fiber (PPF) as the source of roughage and to elucidate the best ratio of the BCAA for fermentability and digestibility improvement. The study was a randomized complete block in vitro experiment of 3 replicates with 33 factorial treatments. The factors were the BCAA, supplemented into the basal diet, each at O,0.1, or 0.2%. Dry matter (DM) of the basal diet composed of 50% PPF, 25% wheat bran, 23.5% coconut oil meal, 0.5% limestone, 0.5% vitaminerals, 0.25% urea, and 0.25% common salt. The diet contained 5.18 MJ (Mega Joule) digestible energy (DE) and 16% crude protein. The BCAA supplementation improved (P < 0.01) digestibility of DM (52.4 vs 60.9O/0) and organic matter (OM) (57.5 vs 64.7O/0). Supplementation of 0.1% Val + 0.2O/0 Leu + 0.1% Ile resulted in the best DM (65.2 + 3.99%) and OM digestibility (69.3 + 4.14%), as well as volatile fatty acids (VFA) production (115 + 15 mM). The BCAA addition however, decreased (P < 0.01) ammonia (3.47 vs 2.36 mM). Apparently it was used for de novo synthesis of microbial amino acids. Based on the response curve of digestibility variables to Ile levels of the 0.1% Val supplemented diets it is concluded that the best levels of BCAA for digestibility and fermentation improvement is 0.1% Val + 0.2% Leu + 0.12O/0 Ile. Even it is not the best, the use of Ile as a single supplement at 0.2O/0 is worth consideration.