The quality of silage of corn grain and spent P. ostreatus mushroom substrate

Abstract

The chemical composition, fermentation quality, mycological and mycotoxicological analyses of silage mixture, made of ground corn grain and spent P. ostreatus mushroom substrate, were investigated in this paper. Dry matter content in high moisture ground corn, at the time of ensiling was 70%, and in the spent substrate (on the Salt Cedar wood shaving basis) was 52.7%. Corn grain to spent substrate ratio in trials was: 100:0% (I), 90:10% (II), 80:20% (III) and 70:30% (IV) respectively. Content of the lignocellulose fractions in silage was slightly increased, and protein content was slightly decreased with the increase of spent substrate content. Contents of the VFA (volatile fatty acids) in silage, pH value, and NH3-N content were for the silage of very good quality. In the spent substrate 9 mold species were found, from which the most frequent were genus Penicillium, Paecilomyces variotii, and Trichoderma harzianum. In ground corn grain silage (I) presence of the yeasts was dominant (90.000/g). In combined trials (II-IV) only Penicillium (P. brevicompactum and P. echinulatum) mold species were found. Presence of molds and yeasts in investigated trials was within tolerated values for ensiled feedstuffs. Mycotoxin presence in silage was not determined.U radu su ispitivani hemijski sastav, kvalitet fermentacije, mikoloska i mikotoksikoloska slika silaza na bazi prekrupe vlaznog zrna kukuruza i supstrata za gajenje gljive Pleurotus ostreatus (bukovaca). Sadrzaj suve materije u vlaznom zrnu kukuruza u vreme siliranja iznosio je 70%, a u supstratu (na bazi piljevine bora) 52,7%. Siliranje je obavljeno u laboratorijskim uslovima, u plasticnim kofama zapremine 3 kg. Tezinski udeo prekrupe vlaznog zrna kukuruza i supstrata u silazi je iznosio: 100:0% (I) 90:10% (II), 80:20% (III) i 70:30% (IV). Uzroci silaze uzimani su 6 nedelja nakon siliranja. Hemijski sastav silaza (I-IV) se menjao u zavisnosti od udela prekrupe vlaznog zrna kukuruza i supstrata. Sa povecanjem udela supstrata (sa 10 na 30%) kolicina lignoceluloznih frakcija u silazi imala je trend blagog porasta, a proteina trend opadanja. Sadrzaj isparljivih masnih kiselina u silazi, vrednost pH silaze i sadrzaj NH3-N bili su u okviru vrednosti koje su karakteristicne za silazu veoma dobrog kvaliteta. U supstratu je identifikovano 9 vrsta plesni od kojih su najvecu ucestalost imali predstavnici roda Penicillium, Paecilomyces variotii i Trichoderma harzianum. U silazi od prekrupe vlaznog zrna kukuruza (I) bilo je dominantno prisustvo kvasca (90.000/g). U uzorcima kombinovanih silaza (II-IV) uocene su iskljucivo Penicillium vrste gljiva (P. brevicompactum i P. echinulatum). Prisustvo plesni i kvasca u ispitanim uzorcima je bilo u tolerantnim granicama za silirana hraniva koja se koriste za stocnu ishranu. Toksikoloskim pretragama nije utvrdjeno prisustvo aflatoksina B1, ohratoksina A, zearalenona i trihotecena tipa A (DAS i T-2 toksin).