Amylase addition increases starch ruminal digestion in dairy cows (original) (raw)
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Journal of Dairy Science, 2014
The objective of this study was to evaluate the effect of an exogenous amylase preparation on digestion of low-and high-starch diets in dairy cattle. Rumen and total-tract nutrient digestibility were measured in a 4 × 4 Latin square design with 28-d periods using 4 firstlactation cows cannulated at the rumen and duodenum. Corn silage-based diets had 20 or 30% starch, attained by changing the composition of concentrate, with or without addition of an exogenous amylase preparation. Effects of the enzyme additive were observed on ruminal digestibility but not at the total-tract level. Ruminal digestibility of starch increased from 75% in control to 81% with amylase supplementation. This difference in ruminal starch digestion was compensated postruminally, so that the total-tract digestibility of starch was almost complete and did not differ between treatments. The amylase supplement also increased the true ruminal digestibility of organic matter but did not affect microbial N flow to the duodenum. Amylase supplement reduced the proportion of acetate and butyrate and increased that of propionate, particularly in the high-starch diet, where it tended to increase the concentration of total volatile fatty acids in the rumen. Other effects were a higher amylase activity in the solid-associated microbial community and a tendency for lower numbers of protozoa. In contrast, we observed no changes in intake, production, dry matter and fiber (neutral detergent fiber and acid detergent fiber) digestibility, or ruminal digestion, and no or small changes on selected fibrolytic and amylolytic bacteria and on the microbial community in general. We conclude that the exogenous amylase improved starch digestion in the rumen in first-lactation cows with moderate intake and production levels.
Journal of Dairy Science, 2003
Effects of conservation method of corn grain and dietary starch concentration on ruminal digestion kinetics were evaluated. Eight ruminally and duodenally cannulated Holstein cows (55 ± 15.9 days in milk; mean ± SD) were used in a duplicated 4 × 4 Latin square design with a 2 × 2 factorial arrangement of treatments. Experimental diets contained either ground high moisture corn (HM) or dry ground corn (DG) at two dietary starch concentrations (32 vs. 21%). Mean particle size and dry-matter concentration of corn grain were 1863 μm and 63.2%, and 885 μm and 89.7%, for HM and DG, respectively. Starch digestibility in the rumen was greater for HM treatments compared with DG treatments, but starch digestibility in the total tract was not affected by conservation method of corn grain because of compensatory digestion in the intestines. The difference in ruminal starch digestibility between HM and DG treatment was greater for high-starch diets (71.1 vs. 46.9%) compared with low-starch diets (58.5 vs. 45.9%). This interaction is attributed to a greater difference in first-order digestion rate of starch between HM and DG treatment in high-starch diets (28.2 vs. 14.6%/h) compared with low-starch diets (16.8 vs. 12.2%/h). This suggests that ruminal starch digestion is a second-order reaction limited by enzyme activities as well as substrate availability; ruminal contents of cows fed lowstarch diets may have insufficient amylolytic activity for maximal starch digestion when readily fermentable starch is available. Rate of neutral detergent fiber digestion in the rumen was slower for high-starch diets and HM treatments compared with low-starch diets and DG treatments, respectively. Effects of corn grain conservation method on ruminal digestion kinetics are greatly altered by starch concentration of diets.
1999
The objective of this paper is to review the literature concerning starch digestion in the rumen of the lactating dairy cow and to propose the framework for a mechanistic model representing this process that may be used as part of a larger model of whole rumen function. The review defines starch as it occurs in the diet of the dairy cow, followed by a detailed description of the digestion of starch in the rumen. Emphasis is placed on the role of the microbial population in the degradation of starch and the significance of both amylolytic bacteria and protozoa. During the investigation, use is made of data gathered from both in vivo, in vitro and in situ studies concerning mainly lactating dairy cows. Regression relationships are presented to describe the significance of dietary starch intake, starch source and processing method on digestion characteristics. The quantity of rumen escape starch is increased at high starch intakes. Maize and sorghum starches tend to be more slowly degraded within the rumen than other cereals and they also benefit to a greater extent from physical and chemical processing techniques designed to increase ruminal and total tract starch digestion. Other factors influencing the nature of starch digestion are also presented in order to allow the interpretation of experimental data and hence the development of a conceptual model of starch digestion. The review subsequently examines starch digestion in the rumen as it is represented in extant models of ruminant digestion. The essential elements of a rumen model that would accurately account for the fate of dietary starch within the rumen are identified. Finally, a scheme representing starch digestion in the dairy cow that may be incorporated into a model of whole rumen function is presented.
Journal of dairy science, 2005
The main objective of this experiment was to examine the effects of the percentage and source of crude protein (CP) and the amount of starch in the diet of dairy cows on ruminal fermentation, nutrient passage to the small intestine, and nutrient digestibility. For this purpose, 6 multiparous Holstein cows fistulated in the rumen and duodenum that averaged 73 d in milk were used in a 6 x 6 Latin square design with a 2 x 3 factorial arrangement of treatments. Two sources of CP [solvent-extracted soybean meal (SBM) and a mixture of SBM and a blend of animal-marine protein supplements plus ruminally protected Met (AMB)] and 3 levels of dietary protein (about 14, 16, and 18%) were combined into 6 treatments. On a dry matter (DM) basis, diets contained 25% corn silage, 20% alfalfa silage, 10% cottonseed, 26.7 to 37% corn grain, and 4 to 13.5% protein supplement. Intakes and digestibilities in the rumen and total tract of DM, organic matter, acid and neutral detergent fiber were unaffected...
Animal Feed Science and Technology, 2005
Two industrial exogenous enzymes, alpha-amylase from Bacillus licheniformis and glucoamylase from Aspergillus niger, were evaluated in vivo and in lambs fed 700 g/kg (dry matter (DM)) sorghum grain diets. Six Suffolk lambs (30 ± 2.5 kg body weight (BW)) fitted with ruminal and duodenal cannulas were randomly allotted to two 3 × 3 Latin square experiments, to evaluate effects of alpha-amylase and glucoamylase on intake, digestibility and ruminal fermentation. The same level of protein from the two enzyme sources (0.0, 1.45 or 2.90 g enzyme/kg DM sorghum) was applied to sorghum. The enzymes were sprinkled on the sorghum 24 h before mixing the diet. The highest level of each enzyme was also fed (45 days) to 15 individually housed lambs (Suffolk crossbred, 22.5 ± 1.4 kg BW) in a completely randomized design (i.e., control, alpha-amylase or glucoamylase) to evaluate lamb performance. The highest activity units/mg protein (P < 0.01) was for the alpha-amylase (4.190) followed by glucoamylase (1.952) and ruminal fluid (0.062). Dry matter, organic matter (OM) and starch intake decreased as level of dietary alpha-amylase increased (linear: P < 0.05), but ruminal starch digestion and total tract digestibility of DM, OM and starch
2018
EFFECT OF EXOGENOUS AMYLASE AND PROTEASE ON RUMINAL METABOLISM, NUTRIENT DIGESTIBILITY, AND LACTATION PERFORMANCE OF DAIRY COWS FED FRESHLY ENSILED CORN SILAGE BASED DIETS LAUREN KAYE SHEARER 2018 The objective of this study was to examine the effects of feeding exogenous amylolytic and proteolytic enzymes on lactation performance of dairy cows fed freshly ensiled corn silage-based diets. We hypothesized that the addition of these enzymes would improve nutrient utilization and consequently lactation performance. Thirty-six Holstein cows [15 multiparous and 15 primiparous; DIM = 132 ± 48 and 6 cannulated (3 multiparous and 3 primiparous; DIM = 164 ± 50] were blocked by milk yield, DIM, parity, and body weights and used in a 9 wk randomized complete block design study.. Treatments were a 40% (DM basis) corn silage TMR with 1) no enzymes (CON), 2) amylolytic enzymes (AMY; 10g/hd/d), and 3) amylolytic and proteolytic enzymes (AMYP; 10g/hd/d +15 g/hd/d). Corn silage was ensiled for 48 d ...
Asian Australasian Journal of Animal Sciences
Eight crossbred (75% Holstein Friesian) cows in mid-lactation were randomly assigned to a switchback design with a 2x2 factorial arrangement to evaluate two nonstructural carbohydrate (NSC) sources (corn meal and cassava chips) with different rumen degradability and used at two levels of NSC (55 vs. 75%) with protein source (supplied by urea in the concentrate mix). The treatments were 1) Low degradable low level of corn (55%) 2) Low degradable high level of corn (75%) 3) High degradable low level of cassava (55%) and 4) High degradable high level of cassava (75%). The cows were offered the treatment concentrate at a ratio to milk yield at 1:2. Urea-treated rice straw was offered ad libitum as the roughage and supplement with 1 kg/hd/d cassava hay. The results revealed that total DM intake, BW and digestion coefficients of DM were not affected by either level or source of energy. Rumen fermentation parameters; NH3-N, blood urea nitrogen and milk urea nitrogen were unaffected by sour...
Journal of Animal Science
Cereal grains are the predominant starch source (SS) for dairy cows; however, starch digestibility varies greatly depending on source, grain processing, and potentially interactions between these factors. The objective was to study the effects of the interactions between SS, and particle sizes (PS) on ruminal fermentation, nutrient flow, starch digestibility, and lactation performance of dairy cows. Four ruminally cannulated multiparous Holstein cows were used in a 4 × 4 Latin square design with a 2 × 2 factorial arrangement of treatments. Two SS (corn or sorghum) used in this study were either finely or coarsely ground (using a 1- or 4-mm screen sieve). Digesta flow was quantified using the reticular sampling technique, applying the triple-marker method. Data were analyzed using the GLIMMIX procedure of SAS version 9.3 (SAS Institute Inc., Cary, NC, USA). For ruminal pH, data were analysed with time as repeated measure. There were no interactions between SS and PS on production or ...