Effect of exogenous protease enzymes on the fermentation and nutritive value of corn silage

Abstract

The objective of this study was to evaluate the effects of adding experimental formulations of exogenous protease enzymes on the fermentation and nutritive value of whole-plant corn ensiled in laboratory silos. Chopped and processed whole-plant corn (36.8% DM) was ensiled without enzymes or treated with 1 of 2 experimental proteases (E85 or E86; AB Vista, Wiltshire, UK) at 20 or 2,000 mg/kg (wet-weight basis). Forages were packed in vacuumed and heat-sealed bags and ensiled for 45 and 150 d at 23±1°C. When compared with untreated silage, addition of proteases and length of ensiling time had no effect on silage pH or concentration of crude protein. The results were similar for the concentrations of acid detergent fiber, neutral detergent fiber, and starch, although protease × time interactions were observed for these components, which were biologically minor. When compared with untreated silages, only treatment with the 2,000-mg/kg application amount of E 0425 resulted in lower neutral detergent fiber after 45 d of ensiling. Proteases did not affect NDF digestibility after 150 d of ensiling when compared with untreated silage. Similarly, treatment with enzymes did not affect the concentrations of lactic and acetic acids or ethanol when compared with untreated silage. Concentrations of NH(3)-N and soluble protein (% of crude protein) increased with storage time compared with concentrations at harvest and were greater for the 2,000-mg/kg doses of proteases when compared with untreated silage at both 45 and 150 d. In vitro ruminal digestibility of starch after 7 h of incubation was 66.3% for freshly chopped corn plants. After 45 d of ensiling, starch digestion was greater for E 0430 applied at the 2,000-mg/kg dose (80.6%) than in all other treatments, with the exception that it was similar to the 2,000-mg/kg dose of E85. After 150 d of ensiling, the 20-mg/kg dose of E 0425 (81.9%), the 2,000-mg/kg dose of E 0425 (82.9%), and the 2,000-mg/kg dose of E 0430 (88.6%) had greater starch digestibility than untreated silage (74.0%). To the best of our knowledge, this is the first study to show that addition of exogenous proteases added to corn forage at the time of harvest can increase in vitro ruminal starch digestibility during silage fermentation. Data suggests that adding exogenous sources of protease enzymes at ensiling may be a method to obtain a high degree of ruminal starch digestibility in corn silage that would normally require longer periods of time to obtain from prolonged storage.

<b>Nutritional composition and aerobic stability of winter cereal silage at different storage times

“…In agreement with these authors, even under low pH conditions during storage, some proteolytic enzymes of the microorganisms of the ensiled mass are still active, degrading the material, especially the prolamins coating the grains, and increasing the amount of ammonia nitrogen (N-NH 3 ). Young, Lim, Der Bedrosian, and Kung Jr. (2012) also registered this same tendency in corn silages stored for long periods.…”

“…Nevertheless, the focus of research on this topic has been mainly on corn , Young, Lim, Der Bedrosian, & Kung Jr., 2012, and for winter forages, there is a lack of researches reported in literature, especially in the evaluation of winter crops for this purpose under the Brazilian conditions. It is worth noting that these cereals are of great importance for their nutritional value, digestibility and ease of cultivation in the southern region of the country, which allow to be an alternative for periods of forage shortage (Fontaneli et al, 2009, Lehmen, Fontaneli, Fontaneli, & Santos, 2014.…”

Effects of length of ensiling and maturity group on chemical composition and in vitro ruminal degradability of whole‐crop maize

“…No influence of storage on maize silage in vitro starch degradability was found by Cone et al. () up to 180 days of ensiling and Young, Lim, Der Bedrosian, and Kung () when comparing untreated maize silage after 45 days and 150 days of ensiling. Also the NDS degradability after 7 hr increased from d0 to d60 and remained unchanged afterwards.…”

“…For the NDS parameters of GP kinetics, there are differences between fresh and ensiled samples. The rate of GP increased as a result of the ensiling process which has also been described by .319 DM = dry matter; NDS = neutral detergent soluble; NDF = neutral detergent fibre; parameters of gas production (GP) were estimated according to Ørskov and McDonald (1979) | 605 Peyrat et al (2014) and Philippeau and Michalet-Doreau (1998) No influence of storage on maize silage in vitro starch degradability was found by Cone et al (2008) up to 180 days of ensiling and Young, Lim, Der Bedrosian, and Kung (2012) when comparing untreated maize silage after 45 days and 150 days of ensiling. Also the NDS degradability after 7 hr increased from d0 to d60 and remained unchanged afterwards.…”

Tempo de armazenamento e manejo do painel no valor nutritivo de silagens de milho

“…O resultado dessa ação é o fornecimento de aminoácidos para a planta ainda na forma de embrião. Em trabalho de revisão realizado por Young et al (2012), uma quantidade considerável de proteases são produzidas por espécies de Aspergillus e Tricoderma (conhecidos por produzir amilase e protease) dentre as quais, a enzima aspártico protease, apresenta atividade em pH baixo e seria essencial no uso de alimentos fermentados. insignificantes (Morrison, 1979), a hemicelulose é parcialmente solubilizada (DER BEDROSIAN; MORRISON, 1979;NESTOR;YAHAYA et al, 2001;).…”