CALABRO', SERENA

INFASCELLI, FEDERICO

PICCOLO, VINCENZO

ZICARELLI, FABIO

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Full Terms & Conditions of access and use can be found athttp://www.tandfonline.com/action/journalInformation?journalCode=tjas20Download by: [University Napoli Federico II] Date: 22 November 2016, At: 05:13Italian Journal of Animal ScienceISSN: (Print) 1828-051X (Online) Journal homepage: http://www.tandfonline.com/loi/tjas20Kinetics fermentation and gas production of theneutral detergent–soluble fraction of fresh forage,silage and hay of Avena sativaS. CalabrÒ, F. Zicarelli, F. Infascelli & V. PiccoloTo cite this article: S. CalabrÒ, F. Zicarelli, F. Infascelli & V. Piccolo (2003) Kinetics fermentationand gas production of the neutral detergent–soluble fraction of fresh forage, silage and hay ofAvena sativa, Italian Journal of Animal Science, 2:sup1, 201-203To link to this article:  http://dx.doi.org/10.4081/ijas.2003.11675960© 2003 Taylor & Francis Group LLCPublished online: 07 Mar 2016.Submit your article to this journal Article views: 4View related articles Kinetics fermentation and gas production of the neutral detergent-soluble fraction offresh forage, silage and hay of Avena sativaS. Calabrò, F. Zicarelli, F. Infascelli, V. PiccoloDISCIZIA, sez. B. Ferrara – Università “Federico II”, Napoli, Italy.RIASSUNTO – Cinetica di fermentazione e produzione di gas della frazione solubile nel detergenteneutro del foraggio fresco, insilato e affienato di Avena sativa – La fermentazione della frazione solubilenel detergente neutro (NDS) di tre foraggi di avena (fresco, insilato ed affienato) è stata stimata con ilmetodo di sottrazione delle curve usando la tecnica in vitro della produzione di gas. La velocità massimadi fermentazione (RM) fu sempre maggiore per l’NDS, seguita dal foraggio intero e dall’NDF. Inoltre, l’RMdell’NDS risultò più elevata per il foraggio fresco (0.106 h-1), seguito dal fieno (0.078 h-1) e dall’insilato(0.048 h-1). È confermata la validità del metodo di sottrazione delle curve, utile anche per valutare letrasformazioni che avvengono durante la conservazione dei foraggi.KEYWORDS: oats, cumulative gas production, neutral detergent soluble fraction.INTRODUCTION – Neutral detergent treatment to evaluate the structural polysaccharides (NDF)removes soluble sugars, pectin substances, starch and the non-carbohydrate fraction (Van Soest, 1991).Despite the widely recognized importance of neutral detergent-soluble carbohydrates (NDS) in the earlystages of forage digestion, little is known about their digestion kinetics because most in vitro methodshave studied the disappearance of insoluble cell wall components. However, knowledge of the degrada-tion characteristics of both fractions is very important to formulate balanced diets for high-yielding ani-mals. Using the in vitro gas production system, Schofield and Pell (1995) measured the kinetics fermen-tation of the NDS fraction using the curve subtraction method. The aim of this experiment was to studythe fermentation kinetics of the NDS fraction of oats (Avena sativa L.) forages (fresh, silage and hay).MATERIAL AND METHODS – Three forages of oats, fresh (FO), ensiled (EO) and hay (OH) wereused in this study. The three forages were analysed according to the standard procedures (ASPA, 1980).The isolated NDF fraction for fermentation studies was prepared as described by Doane et al. (1997). Foreach substrate, whole forage (WF) and its isolated NDF were incubated at 39°C with a bicarbonate-phos-phate-buffer, reducing solution and rumen fluid according to Theodorou et al., (1994). The rumen fluidwas collected before morning feeding from two mature buffaloes fed a standard diet (NDF 43.5 and CP12 %, DM). The fermentation kinetics was measured with the gas production technique using the auto-mated pressure evaluation system (APES) described by Davies et al. (2000). The gas volumes producedby the NDS fraction at each time were calculated from the difference between the average gas yields ofthe WF and its respective NDF, adjusted to represent the amount of NDF present in the initial WF sam-ple (Schofield and Pell, 1995). The cumulative gas data were fitted to the model described by Groot et al.(1996): G(t)=A/[1+(B/t)C] where G represents the amount of gas (ml) produced per g of OM incubated attime t; A denotes its asymptotic value (at t = ∞); B (h) is the time at which A/2 has been formed, and Cis a constant determining the curve sharpness. Moreover, the fractional rate (R) at each time and themaximum rate (RM) were calculated (Groot et al., 1996).ITAL.J.ANIM.SCI. VOL. 2 (SUPPL. 1), 201-203, 2003 201* ASPA - Atti corretti  27-12-2005  16:31  Pagina 201PROC. 15th CONGR. A.S.P.A., PARMA, ITALYRESULTS AND CONCLUSIONS – As expected, the three forages (Table 1) showed a decrease inprotein and an increase in the fibrous fraction due to the preservation methods. The NDF curve for FO(Figure 1, panel A) showed a pronounced lag time in gas production. The latter derived from the NDSfraction was at each time higher than NDF and plays an important role in the early stages of fermenta-tion. The NDS fraction gas production of EO and OH was higher than NDF only until 36 h for the lowersoluble carbohydrate content of the two forages (data not illustrated). As expected, for each forage, thetrend of RM was: NDS>WF>NDF (Figure 1 – panel B, C, D), according to our previous results (Calabrò etal., 2001). Regarding the three forages the RM of NDS showed the following tendency: FO>OH>OE(0.106, 0.078, 0.048 h-1, respectively) (Table 2). Also Doane et al. (1997) found a lower RM for NDS in thesilage compared to the fresh forage and they explained the result with the presence in the silage of sub-stantial amount of organic acids, especially lactate, which contribute to the whole fermentative processless efficiently than the glucose. Besides, the fermentative process of FO NDS, reached the maximumvalue, decreases more rapidly compared to OH and EO, probably due to its higher content in soluble sug-ars compared to the preserved forages. R2 and RDS values indicate in all case the good fitting of the NDSdata, estimated with the subtraction curves method, to the model used. The results of this trial confirmthe validity of the curve subtraction method to study the fermentation kinetics of the neutral detergentsoluble fraction of forages and to evaluate modification during forage preservation. This is a major resultas many methods used to evaluate silage quality do not permit measurement of the fermentation kinet-ics of the soluble carbohydrate fractions and thus correct estimation of the energy available from the feedand the rate at which this energy is available. The curve subtraction method could contribute to resolvethese problems.Table 1. Chemical composition of the tested forages.Fresh oats Ensiled oats Oats hayCrude protein % DM 5.97 5.24 5.50Crude fibre “ 29.8 33.7 39.6NDF “ 60.3 65.7 68.1NDS “ 39.7 34.3 31.9ADL “ 4.50 5.70 6.15NDS (fraction soluble in neutral detergent) = 100 – NDF.Table 2. Model parameters for WF, isolated NDF and NDS of each forage.Fresh oats Ensiled oats Oats hayWF NDF NDS WF NDF NDS WF NDF NDSA, ml/g 222 101 115 272 213 122 275 200 103B, h 15.9 28.5 8.74 24.7 48.4 16.9 21.7 36.7 11.9RM, h-1 0.052 0.032 0.106 0.032 0.016 0.048 0.038 0.022 0.078R2 0.999 0.993 0.999 0.996 0.993 0.998 0.999 0.996 0.996RSD 1.04 2.61 1.07 4.70 2.61 1.57 2.28 3.05 2.12R2: gas production variability explained by the model. All R2 values are significant (P<0.001; n: 30). RSD: residualstandard deviation.202 ITAL.J.ANIM.SCI. VOL. 2 (SUPPL. 1), 201-203, 2003* ASPA - Atti corretti  27-12-2005  16:31  Pagina 202REFERENCES – ASPA, 1980. Zoot. Nutr. Anim., 6:19-34, Calabrò, S., Infascelli, F., Bovera, F.,Moniello, G., Piccolo, V., 2001. J Sci. Food Agric. 82:222-229. Davies, Z., Theodorou, M.K., 2000. Anim.Feed Sci. Technol., Doane, P.H., Schofield, P., Pell, A.N., 1997. J. Anim. Sci. 75:3342-3352. Groot, J.C.J.,Cone, J.W., Williams, B.A., Debersaques, F.M.A., 1996. Anim. Feed Sci. Technol. 64:77-89. Schofield, P.,Pell, A.N., 1995. J. Anim. Sci. 73:3455-3463. Theodorou, M.K., Williams, B.A., Dhanoa, M.S., McAllan,A.B. France, J., 1994. Anim. Feed Sci. Technol. 48:185-197.Figure 1. Cumulative gas production and fermentation rate over time.Panel A: Cumulative gas production (ml per amount of each fraction present in 1 g of OM for FO); Panel B, C and D:fermentation rate (h-1) of FO, EO and OH, respectively. Circles: WF; Squares: NDF; Triangles: NDS.gas, mlrate, h-1rate, h-1rate, h-1PROC. 15th CONGR. A.S.P.A., PARMA, ITALYITAL.J.ANIM.SCI. VOL. 2 (SUPPL. 1), 201-203, 2003 203* ASPA - Atti corretti  27-12-2005  16:31  Pagina 203

Kinetics fermentation and gas production of the neutral detergent–soluble fraction of fresh forage, silage and hay of Avena sativa

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