ABSTRACT
This study was conducted to determine in vitro crude protein degradation [IVDP] parameters and effective crude protein degradability [EPD] of various feeds using the modified in vitro gas production [GP] technique. Feed samples were alfalfa hay, soybean meal, soybean, rapeseed meal, sunflower meal and fish meal. Rumen fluid was collected before the morning feeding from four rumen fistulated lambs [49.4 +/- 3.5 kg, body weight]. Approximately 90 ml of buffered rumen fluid [BRF], 400 mg of feed samples and carbohydrates [maltose, xylose and starch] at four concentrations [100, 200, 300, and 400 mg] were added to screw-cap bottles. Gas production [ml] and ammonia nitrogen concentration [mg] in each bottle were measured at 4, 8, 12, 16, 24, and 30 h post incubation and IVDP was calculated via estimated intercept of linear regression between GP [as main variable, X] and ammonia nitrogen [as dependent variable, Y] using the linear regression procedure. Feed, time and feed x time interaction had significant effect on IVDP [P<0.001]. Estimated EPD values at the outflow rate of 0.06/h for alfalfa hay, soybean meal, soybean, rapeseed meal, sunflower meal and fish meal were 0.56, 0.77, 0.59, 0.45, 0.50 and 0.38, respectively
Subject(s)
Proteolysis , Nitrogen , Gases , Proteins , In Vitro TechniquesABSTRACT
An in vitro experiment was conducted to study the effect of non-fiber carbohydrates [NFC] on ruminal disappearance kinetics of dry matter [DM] and neutral detergent fiber [NDF] of alfalfa hay, wheat bran and unmolassed sugar beet pulp. Non-supplemented or NFC supplemented samples [70 mg/g DM of each feed sample as sucrose [SU] or starch [ST] or SU + ST as 1:1] were incubated in bottles containing 40% rumen fluid medium for 4, 8, 16, 24, 48, and 96 h at 39 [degree sign] C. After each incubation time, unfiltered content was analysed for DM and NDF. Filtered fluid was analysed for ammonia-N concentration. Kinetic disappearance rate was determined using a first order non-linear model. The source of NFC used in the medium containing alfalfa hay caused a significant decrease in DM disappearance [P<0.01]. Feed source, NFC type and incubation time had a significant effect [P<0.01] on NDF disappearance and ammonia-N concentration. In vitro NDF disappearance of unmolassed sugar beet pulp and wheat bran was significantly [P<0.01] decreased by supplementing with ST and SU + ST. The indigestible dry matter fraction of alfalfa hay was significantly increased when it was supplemented by NFC [P<0.05]. The rate of DM disappearance of unmolassed sugar beet pulp was also significantly influenced by supplemental NFC [P<0.05]. The fractional rate of NDF disappearance of alfalfa hay and wheat bran exhibited an increase [P<0.05] in response to adding NFC when compared with the non-supplemented samples. Generally, the results of the present study suggested that in addition to the amount of supplemental carbohydrate fed, the source of supplemental carbohydrate and the basal feed sources might be effective on the effect of supplemental NFC on fiber utilization
ABSTRACT
An in vitro experiment was conducted to determine the effect of supplemental non-fiber carbohydrate [NFC] on the disappearance kinetics of cellulose [Ce] by mixed ruminal microorganisms. Non-supplemented or NFC supplemented cellulose [467 mg NFC/g cellulose as sucrose [CeSu] or starch [CeSt] or a 1:1 mixture of sucrose + starch [CeSuSt]] were incubated for 24, 48, and 96 h at 39°C. After each incubation time, pH, ammonia-N concentration and cellulose disappearance were measured. The disappearance kinetics rate of all samples was determined using first order exponential model of D[t]=D[i].exp [-k. time] + I; where D[t] is potentially digestible fraction; D[i] is potentially digestible residues; k is digestion rate of cellulose [h[-1]] and I is indigestible fraction. In this experiment, inclusion of NFC to the rumen fluid medium resulted in a significant depression [P<0.01] in the extent of cellulose disappearance. The disappearance rate constant of cellulose was significantly higher [P<0.05] in non-supplemented samples as compared with those treatments containing NFC. The indigestible fraction of cellulose was significantly higher [P<0.05] for treatments containing sucrose or sucrose + starch as the source of supplemental NFC as compared with nonsupplemented cellulose. However, when starch was added, the indigestible fraction of cellulose was similar to those of non-supplemented samples. The inclusion of NFC resulted in a significant reduction [P<0.01] in pH of the medium, but had no significant effect [P>0.05] on ammonia-N concentration
Subject(s)
Animals , Carbohydrates , AmmoniaABSTRACT
Ruminal, post-ruminal and total tract crude protein disappearance of alfalfa hay and barley grain were measured using in vivo, in situ mobile bag and three-step in situ/in vitro enzyme procedures [3-step]. For in vivo, four Baluchi lambs [49.4 +/- 3.5 kg, body weight] were used in a 2 _ 2 Latin square design within 2 periods [24 days of each period]. Experimental diets were made of two alfalfa hay: barley grain ratios [DM basis] as 1.0:0.0 and 0.5:0.5. Diets were fed to animals for 24 days, with 7 days of feces collection. In situ mobile bag technique was followed by 12 h rumen incubation and then intestinal movement of the bags in rumen and post-rumen cannulated Holstein steers. The three-step procedure was followed by rumen incubation of samples for 12 h [using polyester bags] and enzymatic incubation of ruminal undegradable samples. In vivo total tract crude protein disappearance of alfalfa hay and barley grain [0.74 and 0.69, respectively] was significantly [P<0.01] lower than in situ mobile nylon bag [0.89 and 0.96, respectively] and the 3-step procedure [0.81 and 0.89, respectively]. Total tract crude protein disappearance from in situ mobile bag was significantly [P<0.01] higher than the 3-step technique. Post-ruminal disappearance of ruminal undegradable crude protein from alfalfa hay and barley grain using in situ mobile bag method [0.69 and 0.86, respectively] was significantly [P<0.01] higher than the 3-step enzymatic method [0.49 and 0.56, respectively]. Results of the present study showed that there was a significant difference between in vivo, in situ mobile bag and 3-step methods when total tract crude protein disappearance of barley grain and alfalfa hay was evaluated