Title Utjecaj dodatka inokulanta na promjene sadržaja kiselina tijekom aeracije silaže visokovlažnog zrna kukuruza
Title (english) The effect of inoculant application on changes in acid content during aeration of high-moisture corn
Author Vedrana Perišić
Mentor Marija Duvnjak (mentor)
Committee member Marija Duvnjak (predsjednik povjerenstva)
Committee member Kristina Kljak (član povjerenstva)
Committee member Goran Kiš (član povjerenstva)
Granter University of Zagreb Faculty of Agriculture (Animal Nutrition) Zagreb
Defense date and country 2022-09-28, Croatia
Scientific / art field, discipline and subdiscipline BIOTECHNICAL SCIENCES Agronomy
Abstract Aeracija aktivira nepoželjne mikroorganizme koji uzrokuju kvarenje silaže, a ono je vidljivo kroz porast temperature silaža. Također, aeracijom dolazi i do pada u koncentracijama mliječne kiseline i hlapivih masnih kiselina (HMK). Mliječna kiselina je glavna konzervirajuća kiselina dok octena kiselina osigurava dulju aerobnu stabilnost silaža. U pripremi silaža koriste se liofilzirane bakterije mliječne kiseline kao inokulanti. Na taj način omogućava se usmjerena fermentacija u silažama i proizvodnja kiselina te viša aerobna stabilnost silaža. Cilj ovog rada bio je istražiti utjecaj dodatka inokulanta Lactiplantibacillus plantarum tijekom pripreme silaža na aerobnu stabilnost visokovlažnog zrna kukuruza u periodu sedmodnevne aeracije. U silažama sa i bez dodatka inokulanta u periodu od 7 dana aeracije promatrane su promjene koncentracija mliječne kiseline, HMK, etanola i metanola koje su kvantificirane HPLC metodom te dodatno ST i temperatura silaža. U cijelom periodu aeracije silaže su ostale stabilne jer temperatura u silažama nije bila viša za 2 °C od temperature okoliša. Suha tvar silaža ostala je stabilna u cijelom periodu (P=0,257), dok su svi ostali parametri pokazali signifikantne promjene tijekom aeracije (za sve parametre P<0,001 osim za propionsku kiselinu P=0,024 i metanol P=0,012). Silaže s dodanim inokulantom imale su višu koncentraciju mliječne kiseline u cijelom periodu aeracije u odnosu na kontrolne silaže (P<0,001) dok su HMK i alkoholi bili viši u kontrolnim silažama (octena i propionska kiselina P=0,002; alkoholi P<0,001) što je pokazatelj da je siliranje u silažama s dodanim inokulantom bilo homofermentativno. Koncentracija mliječne kiseline u kontrolnim silažama na kraju aeracije u odnosu na početak bila je duplo niža (11,05 vs 6,84 g/kg ST), dok je u inokuliranim uzorcima ostala stabilna (18,24 vs 17,96 g/kg ST). Tijekom aeracije koncentracija octene kisline je pala u silažama s inokulantom (s 1,30 na 0,91 g/kg ST) dok je u kontrolnim silažama došlo do porasta octene kiseline (s 1,90 na 2,61 g/kg ST). Propionska kiselina, metanol i etanol imali su slične promjene u silažama s inokulantom i kontrolnim silažama ali uz različite intenzitete. Rezultati istraživanja pokazuju da iako su silaže ostale stabilne u cijelom periodu aeracije dodatak inokulanta utječe na promjene temperature u silažama ali i na promjene u kiselinama i alkoholima. Može se zaključiti kako dodatak inokulanta tijekom siliranja utječe na promjene kiselina i alkohola te aerobnu stabilnost silaža tijekom aeracije.
Abstract (english) Aeration activates undesirable microorganisms that cause silage spoilage, which can be seen by the increase in silage temperature. In addition, aeration decreases the concentration of lactic acid and volatile fatty acids (VFA). Lactic acid is the main preservative acid, while acetic acid provides longer aerobic stability of silage. Lyophilized lactic acid bacteria are used as inoculants in the production of silage. In this way, proper fermentation and acid production, as well as higher aerobic stability of silages, are enabled. The aim of this study was to investigate the influence of the addition of the inoculant Lactiplantibacillus plantarum during silage preparation on the aerobic stability of high-moisture corn during the seven-day aeration period. Changes in the concentrations of lactic acid, VFA, ethanol, and methanol in silages with and without the addition of the inoculant were observed over a 7-day period, quantified by the HPLC method, as well as ST and the temperature of the silage. Throughout the aeration period, the silages remained stable, as the temperature in the silages was not 2 °C higher than the ambient temperature. Silage dry matter remained stable throughout the period (P=0.257), whereas all other parameters showed significant changes during aeration (for all parameters P<0.001 except for propionic acid P=0.024 and methanol P=0.012). Silages with inoculant addition had higher lactic acid concentration than control silages throughout the aeration period (P<0.001), while VFAs and alcohols were higher in control silages (acetic and propionic acid P=0.002; alcohols P<0.001), indicating that ensiling was homofermentative in silages with inoculant addition. At the end of aeration, lactic acid concentrations were twice as low in control silages compared to the beginning (11.05 vs. 6.84 g/kg DM), while they remained stable in inoculated samples (18.24 vs. 17.96 g/kg DM). During aeration, acetic acid concentration decreased in the silages with inoculant (from 1.30 to 0.91 g/kg DM), while in the control silages there was an increase in acetic acid (from 1.90 to 2.61 g/kg DM). Propionic acid, methanol and ethanol showed similar changes in silages with inoculant and control silages, but with different intensity. The research results show that although the silages remained stable throughout the aeration period, the addition of inoculants affected the temperature changes in the silages as well as the changes in acids and alcohols. It can be concluded that the addition of inoculants during ensiling affects the change of acids and alcohol and the aerobic stability of silage during aeration.
Keywords
visokovlažno zrno kukuruza
aerobna stabilnost
inokulant
kiseline
Keywords (english)
high-moisture corn
aerobic stability
inoculant
acids
Language croatian
URN:NBN urn:nbn:hr:204:775938
Study programme Title: Animal Nutrition and Feed Science Study programme type: university Study level: graduate Academic / professional title: magistar/ magistra inženjer/inženjerka hranidbe životinja i hrane (magistar/ magistra inženjer/inženjerka hranidbe životinja i hrane)
Type of resource Text
File origin Born digital
Access conditions Access restricted to students and staff of home institution
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Created on 2022-11-28 08:50:18