• Asian-Australasian Journal of Animal Sciences
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• v.19 no.8
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• pp.1120-1126
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• 2006

Dry matter (DM) degradation of leaves from Quercus cercis, Quercus libari, Quercus branti, and Quercus coccifera was determined using two different techniques: (i) in vitro gas production and (ii) the nylon bag degradability technique. In vitro gas production in the presence or absence of PEG and in situ DM disappearance were measured at 3, 6, 12, 24, 48, 72 and 96 h. In situ and in vitro DM degradation kinetics were described using the equation y = a+b ($1-e^{-ct}$). At all incubation times leaves from Quercus branti incubated with or without PEG gave significantly higher gas production than the other oak leaves except for 3 and 6 h incubation when leaves from Quercus branti without PEG supplementation only gave higher gas production than Quercus cercis and Quercus coccifera. At all incubation times except at 3, 6 and 12 h the DM disappearance from Quercus branti was significantly higher than the other species. Generally, PEG supplementation considerably increased the gas production at all incubation times and estimated parameters such as gas production rate ($c_{gas}$), gas production (ml) from the quickly soluble fraction ($a_{gas}$), gas production (b) from the insoluble fraction, potential gas production (a+b). However, all oak leaves did not give the same response to the PEG supplementation. Although the increase in gas production at 96 h incubation time was 8.9 ml for Quercus libari the increase was 5.5 ml for Quercus coccifera. It was concluded that except at early incubation times the relationships between the two methodologies seem to be sufficiently strong to predict degradability parameters from gas production parameters obtained in the presence or absence of PEG.

• Animal Bioscience
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• v.34 no.1
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• pp.56-65
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• 2021

Objective: This study was conducted to investigate the effects of molasses and Lactobacillus plantarum on the ensiling quality and in vitro rumen fermentation of sudangrass silage prepared with or without wilting. Methods: The ensiling experiment, measured with 3 replicates, was carried out according to a 2×4 (wilted stages×additives) factorial treatment structure. Dry matter of the fresh (210 g/kg fresh matter) or wilted (305 g/kg fresh matter) sudangrass were ensiled (packed into 5.0-L plastic jars) without additive (control) or with molasses (M), Lactobacillus plantarum (LP), or molasses + Lactobacillus plantarum (M+LP). After 60 days of ensiling, the silages were analyzed for the chemical, fermentation, and in vitro characteristics. Results: After 60 days of ensiling, the fermentation parameters were affected by wilted, the additives and the interactions of wilted with the additives (p<0.05). The M+LP treatment at wilted had higher lactic acid levels and V-score (p<0.05) but lower pH values and butyric acid concentrations than the other treatments. In comparison with sudangrass before ensiling, after ensiling had lower dry matter and higher non-fibrous carbohydrate. The in vitro gas production, in vitro dry matter digestibility, in vitro crude protein digestibility, and in vitro acid fiber detergent digestibility changed under the effects of the additives. Significant interactions were observed between wilted and the additives in terms of in vitro gas production at 48 h, asymptotic gas production, gas production rate, half time, and the average gas production rate. The total volatile fatty acid levels in the additive treatments were higher than those in the control. Conclusion: Wilting and supplementation with molasses and Lactobacillus plantarum had the ability to improve the ensiling quality and in vitro nutrient digestibility of sudangrass silage. The M+LP treatment at wilted exhibited the strongest positive effects on silage quality and in vitro ruminal fermentation characteristics.

• Asian-Australasian Journal of Animal Sciences
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• v.13 no.8
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• pp.1084-1093
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• 2000

An in vitro gas production system was used to investigate the influence of various substrate mixtures on a natural mix of rumen microbes by measurement of fermentation end-products. The treatments were combinations of cassava (15.0, 30.0 and 45.0%) with different roughage sources (ruzi grass, rice straw or urea treated rice straw). Microbial biomass, net $^{15}N$ incorporation into cells, volatile fatty acid production, gas volume and rate of gas production increased linearly with increasing levels of cassava inclusion. There was also an effect of roughage source, with rice straw being associated with the lowest values for most parameters whilst similar values were obtained for ruzi grass and urea treated rice straw. The results suggest that microbial growth and fermentation rate increase as a function of readily available carbohydrate in the substrate mixture. A strong linear relationship between $^{15}N$ enrichment, total volatile fatty acid production and gas production kinetics support the suggestion of the use of the in vitro gas production system as a tool for screening feedstuffs as an initial stage of feed evaluation.

• Asian-Australasian Journal of Animal Sciences
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• v.29 no.1
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• pp.51-61
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• 2016

In order to provide recommendations on the most useful forage species to smallholder farmers, eleven grass and eleven legume forages grown in Abomey-Calavi in Republic of Benin were investigated for nutritive value (i.e. chemical composition and energy content) and fermentation characteristics (i.e. gas and volatile fatty acid production, organic matter degradability). The in vitro gas production technique was used, incubating the forages for 120 h under anaerobic condition with buffalo rumen fluid. Compared to legume, tropical grass forages showed lower energy (8.07 vs 10.57 MJ/kg dry matter [DM]) and crude protein level (16.10% vs 19.91% DM) and higher cell wall content (neutral detergent fiber: 63.8% vs 40.45% DM), respectively. In grass forages, the chemical composition showed a quite high crude protein content; the in vitro degradability was slightly lower than the range of tropical pasture. The woody legumes were richer in protein and energy and lower in structural carbohydrates than herbaceous plants, however, their in vitro results are influenced by the presence of complex compounds (i.e. tannins). Significant correlations were found between chemical composition and in vitro fermentation characteristics. The in vitro gas production method appears to be a suitable technique for the evaluation of the nutritive value of forages in developing countries.

• Asian-Australasian Journal of Animal Sciences
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• v.21 no.1
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• pp.59-65
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• 2008

Six total mixed rations (TMR) containing 0, 4, 6, 8, 10, 12% tannin (TMR I-VI), using Accacia nilotica pods as a source of tannin, were used to study the effect of Acacia tannin on in vitro nutrient digestibility and gas production in goats. This study also investigated the degraded products of Acacia nilotica tannin in goat rumen liquor. Degraded products of tannins were identified using high performance liquid chromatography (HPLC) at different hours of incubation. In vitro digestibility of dry matter (IVDMD) and organic matter (IVOMD) were similar in TMR II, and I, but declined (p<0.05) thereafter to a stable pattern until the concentration of tannin was raised to 10%. In vitro crude protein digestibility (IVCPD) decreased (p<0.05) with increased levels of tannins in the total mixed rations. Crude protein digestibility was much more affected than digestibility of dry matter and organic matter. In vitro gas production (IVGP) was also reduced (p<0.05) with increased levels of tannins in the TMR during the first 24 h of incubation and tended to increase (p>0.05) during 24-48 h of incubation. Gallic acid, phloroglucinol, resorcinol and catechin were identified at different hours of incubation. Phloroglucinol and catechin were the major end products of tannin degradation while gallate and resorcinol were produced in traces. It is inferred that in vitro nutrient digestibility was reduced by metabolites of Acacia nilotica tannins and ruminal microbes of goat were capable of withstanding up to 4% tannin of Acacia nilotica pods in the TMR without affecting in vitro nutrient digestibility.

• Asian-Australasian Journal of Animal Sciences
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• v.20 no.7
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• pp.1049-1056
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• 2007

This study was conducted to compare the methane ($CH_4$) production estimated by in vivo (sulfur hexafluoride tracer technique ($SF_6$)) with that of two in vitro rumen simulation (RUSITEC) and gas production (IVGPT)) techniques. Four adult dry Holstein cows, aged $7.4{\pm}3.0$ years and weighing $697{\pm}70$ kg, were used for measuring methane production from five diets by the $SF_6$ technique. The experimental diets were alfalfa hay ($D_1$), corn silage + soybean meal (SBM) (910: 90, $D_2$), Italian rye grass hay +SBM (920: 80, $D_3$), rice straw +SBM (910: 90, $D_4$) and Sudan grass hay +SBM (920: 80, $D_5$). Each diet was individually fed to all 4 cows and 5 feeding studies of 17 d each were conducted to measure the methane production. In the RUSITEC, methane production was measured from triplicate vessels for each diet .In vitro gas production was measured for each of the diets in triplicate syringes. The gas produced after 24 and 48 h was recorded and gas samples were collected in vacuum vials and the methane production was calculated after correction for standard temperature and pressure (STP). Compared to the $SF_6$ technique, estimates of methane production using the RUSITEC were lower for all diets. Methane production estimated from 24 h in vitro gas production was higher (p<0.001) on $D_1$ as compared to that measured by $SF_6$, whereas on $D_2$ to $D_5$ it was lower. Compared to $SF_6$, methane production estimated from 48 h in vitro gas production was higher on all diets. However, methane estimated from the mean of the two measurement intervals (24+48 h/2) in IVGPT was very close to that of $SF_6$ (correlation 0.98), except on $D_1$. The results of our study confirmed that IVGPT is reflective of in vivo conditions, so that it could be used to generate a database on methane production potential of various ruminant diets and to examine strategies to modify methane emissions by ruminants.

• Asian-Australasian Journal of Animal Sciences
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• v.20 no.4
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• pp.517-522
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• 2007

The aim of this study was to compare in vitro gas production kinetics, metabolizable energy (ME), organic matter digestibility (OMD) and microbial protein (MP) production of widely used legume hays in ruminant nutrition in Turkey. Gas production were determined at 0, 3, 6, 12, 24, 48, 72 and 96 h and their kinetics were described using the equation p = a+b ($1-e^{-ct}$). There were significant differences among legume hays in terms of chemical composition. The crude protein content of legume hays ranged from 11.7 to 18.6% of dry matter (DM); crude fat from 2.1 to 3.5% DM; neutral detergent fiber from 35.6 to 52.0% DM; acid detergent fiber from 32.0 to 35.5% DM and acid detergent lignin 1.7 to 11.0% DM. Total gas production after 96 h incubation ranged between 61.67 and 76.00 ml/0.200 g of substrate. At 24, 72 and 96 h incubation the total gas production for common vetch were significantly (p<0.01) higher than those of the other legume hays. The ME, OMD and MP of legume hays ranged from 9.09 to 11.12 MJ/kg DM, 61.30 to 75.54% and 90.35 to 138.05 g/kg DM, respectively. The ME, OMD and MP of common vetch was significantly (p<0.01) higher than those of the other hays due to low cell-wall contents and high crude protein. At the end of the experiment, differences in chemical composition of legume hays resulted in the differences in the in vitro gas production, gas production kinetics and the estimated parameters such as ME, OMD and MP. Common vetch can be recommended to hay producers and ruminant breeders, due to high ME, OMD and MP production.

• Asian-Australasian Journal of Animal Sciences
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• v.14 no.11
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• pp.1580-1584
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• 2001

A study was conducted to estimate the nutritive value of some selected acacia forages using palatability index, in sacco degradability and in vitro gas production characteristics. Ten wethers (mean wt. $18{\pm}3.5kg$) were offered Acacia tortilis, Acacia nilotica, Acacia mellifera, Acacia brevispica, Acacia Senegal and Leucaena leucocephala (control) using a cafeteria system to determine the species preference by the animals. The acacia species were rich in nitrogen and showed variable palatability pattern. Significant (p<0.05) differences in relative palatability index (RPI) were detected among the species with the following ranking: brevispica > leucaena > mellifera > tortilis > Senegal > nilotica. Acacia nilotica appeared to be of low relative palatability with RPI of 24% and this was attributed to relatively high phenolic concentrations. The DM potential degradability (B) and rate of degradation (c) of the species were significantly (p<0.05) different, ranging from 40.1 to 59.1% and 0.0285 to 0.0794/h respectively. Acacia species had moderate levels of rumen undegradable protein, much higher than that in leucaena. In vitro gas production results indicated the effect of polyphenolic compounds on the fermentation rate, with lower gas production recorded from A. nilotica and tortilis. Based on RPI, A. brevispica and mellifera were superior to the rest and comparable to L. leucocephala. Long-term feeding trials are required with the superior species when used as protein supplements to poor quality diets.

• Asian-Australasian Journal of Animal Sciences
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• v.12 no.5
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• pp.747-751
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• 1999

The Hohenheim in vitro gas test was used to assess the nutritional value of some crop residues of known in vivo digestibility. The crop residues are groundnut shells (GNS) corn cobs (CC); cassava peels (CaP); unripe and ripe plantain peels (UPP, RPP) and citrus pulp/peels (CPP). Compared to other crop residues, crude protein (CP) content of CC was low. Except for CaP and CPP that had low neutral detergent fibre (NDF) and acid detergent fibre (ADF), other residues contained a high amount of cell wall constituents. Net gas production was significantly different among the crop residues (p<0.05). Gas production was highest in CPP followed by CaP. CC, UPP and RPP have the same volume of net gas production, while the least net gas production was in GNS. True dry matter (TDM) digestibility was significantly different (p<0.05) among the residues. GNS was the least in TDM digestibility. CaP, UPP and RPP had similar TDM digestibility values, while the highest TDM digestibility was obtained in CPP. OM digestibility was different among the residues (p<0.05). CaP and CPP had the same ME value while CC, UPP and RPP had close ME values and GNS the least in ME (p<0.05). The potential extent (b) and rate (c) of gas production were statistical different among the residues (p<0.05). The Hohenheim gas test gave high in vitro organic matter (OM) digestibility for CC, CaP, UPP and RPP and CPP. Fermentable carbohydrates and probably available nitrogen in the crop residues influenced net gas production. The results showed that crop residues besides, providing bulk are also a source of energy and fermentable products which could be used in ruminant livestock production in the tropics.

• Asian-Australasian Journal of Animal Sciences
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• v.18 no.7
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• pp.990-996
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• 2005

The effect of diets varying in level and source of nitrogen (N) and fermentable organic matter on dynamic characteristics of microbial populations in rumen liquor and their impact on substrate fermentation in vitro was studied. The diets tested were straw alone, straw+concentrate mixture and straw+urea molasses mineral block (UMMB) lick. The same diets were taken as substrates and tested on each inoculum collected from the diets. Diet had no effect on the amino acid (AA) composition of either bacteria or protozoa. Differences among the diets in intake, source of N and OM affected bacterial and protozoal characteristics in the rumen. Upper asymptote of gas production (Y$\alpha$) had a higher correlation with bacterial pool size and production rate than with protozoal pool size and production rate. Among the parameters of the gas production model, Y$\alpha$ and lag time in total gas has showed significant (p<0.01) correlation with bacterial characteristics. Though the rate constant of gas production significantly differed (p<0.01) between diet and type of straw, it was least influenced by the microbial characteristics. The regression coefficient of diet and type of straw for Y$\alpha$ indicated that the effect of diet on Y$\alpha$ was threefold higher than that of the straw. As microbial characteristics showed higher correlation with Y$\alpha$, and diet had more influence on the microbial characteristics, gas production on a straw diet could be used effectively to understand the microbial characteristics.