LYSOZYME AS A POTENTIAL SILAGE ADDITIVE

Four experiments were performed to determine if lysozyme could inhibit clostridial fermentation during ensiling. In Experiments 1 and 2, unw ilted perennial ryegrass (lolium perenne) received either no additive, formic acid, or one of three lysozyme treatments (20, 50 and 100 mg/k g fresh matter (FM) in Experiment 1; 20, 100 and 500 mg/kg FM in Exper iment 2). The grass was ensiled in plastic-pipe silos (13.3 1), stored under ambient conditions and opened for analysis after 67 and 29 days in Experiments 1 and 2, respectively. In Experiments 3 and 4, unwilte d lucerne (Medicago sativa) received either no additive or Clostridium tyrobutyricum inoculant alone or with lysozyme at 20 or 100 mg/kg FM. The lucerne was ensiled in centrifuge tubes (100 ml), incubated at 39 -degrees-C, and duplicate silos were analysed at 1, 2, 4, 8, 16 and 32 (or 33) days. In Experiment 1, no butyric acid was detected in any of the silages. In Experiment 2, all silages underwent extensive clostri dial fermentation, but the higher lysozyme treatments affected the rel ative proportions of clostridial fermentation products. In both Experi ments 3 and 4, the lucerne silages treated with 20 mg lysozyme underwe nt considerable clostridial fermentation and there was no difference i n fermentation characteristics between these silages and those receivi ng clostridial inoculant alone. Treatment with lysozyme at 100 mg/kg d id not prevent clostridial activity during 32 days of fermentation but delayed its development. Lysozyme activity in silage extracts was vir tually absent even within 1 day of ensiling, suggesting that lysozyme was inactivated or hydrolysed by proteolytic activity.