DEGRADATION BY FICIN OF PROTEIN FROM ALFALFA HAY CONSERVED AS CONVENTIONAL AND LABORATORY-SCALE BALES

Ficin was utilized in a 2-h in vitro incubation procedure to character ize the partitioning of N into fractions based on resistance of alfalf a (Medicago sativa L.) proteins to enzymatic degradation. Objectives i ncluded evaluation of the following treatment effects on N partitionin g: (i) moisture content; (ii) laboratory bale density; (iii) laborator y baling without heating during storage; (iv) spontaneous heating in l aboratory bales; and (v) conventional baling. Alfalfa at three moistur e levels (268, 229, and 185 g kg(-1)) was conserved in the following b ale types: (i) conventional bales; (ii) laboratory bales made at 1.0, 1.3, 1.7, and 2.0 times the density of conventional bales and incubate d in two environments (straw stacks or insulated boxes); or (iii) a pr estorage control, Significant (P less than or equal to 0.05) moisture x bale type interactions were observed for most N fractions, indicatin g N partitioning among bale types was greatly changed in high-moisture hay, but remained relatively stable in dry hay, Except for the Pool-C N fraction, which includes Maillard reaction products, laboratory-bal e density generally had little effect on N partitioning. At the medium and low moisture levels, prestorage controls had more Pool-A N (great er buffer solubility) than did nonheated laboratory bales. Heating in laboratory bales facilitated additional significant change in N fracti ons, relative to nonheated laboratory bales. While Maillard reaction p roducts increased in response to laboratory bale density, large increa ses in the portion of potentially available N most resistant to enzyma tic degradation (B-2 subfraction), appeared dependent on large heat in crements incurred specifically in conventional bales.