Effect of drying temperature on in vitro gas production and energy content of wheat dried distillers grains using mixed rumen micro-biota obtained from Holstein steers

نویسنده:
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سال
: 2012
چکیده: The aim of the present study was to evaluate the

effect of drying temperature on in vitro digestibility of organic

maner (DOM), metabolizable energy (ME) and net energy for

lactation (NEL) values, and drying efficiency of wheat dried

distillers grains (WDDG), applied a tower heat-dryer system,

using mixed rumen micro-biota obtained from Holstein steers.

The technology was developed to dry WDDG when it was

flewconstantlythrough a tower (10 m length) against a current

of pressure of heated air at 185 .C (LAT) or 246 .C (HAT)

with a pressure suction cooling. Dried samples were obtained

from the lowest and the highest applied temperature, then

ground to pass through a I-mm screen and subjected to a gas

production technique. Rumen content was collected from four

ruminally /istulated steers (420*13 kg, body weight) and

straioed through 4 layers of cheesecloth. The laboratory

handling of rumen fluid was carried out under a continuous

flow of C02. In vitro incubation of the samples was done

using a manual pressure transducer technique. Approximately

200 mg of each sample was weighed into a 120 ml serum

bottle (n= 8). The bonles were pre-warmed at 38.6 .C before

the injectionono ml rumen fluid-buffer mixture (10 ml rumen

fluidand 20 ml buffer solution) into each bottle followed by

incubation in a water bath at 38.6 .C. Gas pressure was

recordedafter 2, 4,8, 12 and 24 h of incubation and converted

to gas volume using experimentally deteomined calibrated

curve. Metabolizable energy, NEL and DOM values of the

samples were calculated using following equations: ME

(MJlkg DM)= 1.56 +0.1390 GP +0.0074 XP +0.0178 XL;

NEL(MJlkg DM)= 0.1010 GP +0.0051 XP +0.011 XL; DOM

(glkg DM)= 14.88 +0.8893 GP +0.0448 XP +O.065IXA.

WhereGPis netgasproducedafter 24 h of incubation(mVO.2

g OM), and XP, XL and XA are crude protein, crud fat and

ash contentof the feed (glkg DM), respectively.

Data were analysed using the GLM procedure of SAS.

Results indicated that air temperature of the new drying

technique had a significant (P< 0.05) effect on ME (MJlkg

DM), NEL (MJlkg DM) and DOM (LAT= 9.7, 5.7 and 610,

HAT= 10.0, 5.8 and 640, respectively) of the WDDG samples

evaluated. Results indicated that the drying process of the

samples dried at the air temperature of 185 .C was less

efficient than the highest applied temperature, as observed in

9.8% of more consumed drying time with similar moisture

output compared with the HAT samples. Therefore, the

highest air temperature used in present study was more the

efficient and safe for drying and enhancing the nutritive values

of the WDDG samples evaluated.
کلیدواژه(گان): digestibiliy,metabolizable energy,net energy,wheat

wheat dried distillers grains
کالکشن :
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