Digestibility Of Barley Research Articles

Effect of extrusion on available energy and amino acid digestibility of barley, wheat, sorghum, and broken rice in growing pigs.

The main objective of this study was to determine available energy and nutritional digestibility of extruded cereals and the effect of extrusion on the nutritional value of feed ingredients, aiming to provide scientific basis for efficient application of extrusion in the diets of growing pigs. In Exp. 1, 48 crossbred growing pigs (Duroc×Landrace×Yorkshire) with an initial body weight (BW) of 34.6±2.2 kg were selected and fed with eight diets (non-extrusion or extrusion) to determine the digestible energy (DE), metabolizable energy (ME), and nutrients digestibility. Eight diets included extruded grains (barley, wheat, sorghum, or broken rice), while four had unprocessed grains. In Exp. 2, 9 diets were formulated including 4 cereals with extrusion or non-extrusion and a N-free diet. In addition, 9 growing pigs (BW = 22.3±2.8 kg) were fitted with T-cannula in the distal ileum and arranged in a 9×6 Youden square design. Results show that apparent total tract digestibility of gross energy, dry matter, organic meal, ether extract, neutral and acid detergent fiber was not affected by the extrusion process and there was no interaction between cereal type and extrusion treatment on DE, ME. However, the apparent total tract digestibility for crude protein (CP) increased markedly (p<0.05). The standardized ileal digestibility (SID) of all amino acids (AA) except for leucine remarkably increased by extrusion (p<0.05). There was an interaction on the SID of arginine, leucine, isoleucine, methionine, phenylalanine, cystine, and tyrosine in growing pigs between type of grain and extrusion treatment (p<0.05). Extrusion increased the ileal digestibility of CP and most AA in cereals, however, the DE and ME of cereals were not affected in growing pigs.

52 Evaluation of barley digestibility with an in vitro total tract digestion simulation

Methods of investigating the digestibility of horse feeds have focused on the hindgut fermentation of feedstuffs, neglecting the foregut digestibility. The aim of this study was to evaluate the foregut digestibility and hindgut fermentation of barley in vitro. Three forms of barley (untreated (UB), micronised (MB)and torrefied (TB)) were evaluated. Substrates were ground to 2-mm and weighed into polyester bags (ANKOM R1020). Three replicates of 5 g (DM) per substrate were weighed into large bags (10 × 20 cm) while 4 replicates of 1g (DM) per substrate were weighed into smaller bags (4 × 10 cm). An in vitro simulated foregut digestion was set up as follows: one beaker containing artificial saliva (2.86 g/L NaCl, 1.5 g/L KHCO 3 , 2.77 g/L NaHCO 3 at pH 8.6), one with artificial gastric juice (2g/L pepsin, 1L 0.075M HCl, 10g/L Bioacidophilus powder at pH 3) and one with artificial pancreatic juice (2g/L pepsin, 1L 0.075M HCl, 85 mL/L pancreatic solution at pH 7 (45 PancrexV capsules/200 mL H 2 O)). All bags were incubated for 3h10min at 38°C: first suspended for 10min in artificial saliva, 2 h in artificial gastric juice and 1h in artificial pancreatic juice. At this point the large bags were rinsed in water and oven-dried for 24h at 60°C to determine foregut DM loss (F-DMd). Small bags were incubated for a further 72h within culture bottles with a digestion medium and equine fecal inoculum. After fermentation, suspension pH was measured, and bags oven-dried to calculate total DM loss (T-DMd). A one-way ANOVA analysis was conducted on Minitab Ⓡ 2019 to determine substrate effect on F-DMd, T-DMd and pH; significance level was set at P < 0.05 and Tukey post-hoc test used to define pairwise differences. The F-DMd was highest for TB, followed by MB, with UB being lowest ( P < 0.001), while T-DMd was highest for MB compared with UB ( P < 0.05); pH after fermentation was lower for UB in comparison with TB ( P < 0.01). These findings suggest that both micronisation and torrefaction improve the in vitro foregut digestibility of barley; however, the greatest effect was seen with torrefaction.

Effect of Cyclotrichium niveum Essential Oil on Rumen Microbial Fermentation and in vitro Digestibility of Barley

The digestibility of feed in ruminants and the volatile fatty acids (VFA) resulting from digestion directly affect animal performance. It has long been studied on the use of essential oils as an alternative to antibiotics to ensure optimum conditions for the rumen environment. Cyclotrichium niveum (mountain mint) essential oil is rich in antimicrobial agents. In this study different doses (0, 50, 100 and 150 mg/L of culture fluid) of Cyclotrichium niveum essential oil was incubated 24 hours with barley in diluted ruminal fluid takes from fistulated cows fed with a 40:60 concentrate:forage diet in order to assess the effects on rumen microbial fermentation and in vitro true digestibility of barley. True digestibility of barley was determined in ANKOM Daisy Incubator. All doses of Cyclotrichium niveum significantly (P&amp;lt;0.001) decreased the in vitro dry matter (DM), organic matter (OM), neutral detergent fiber (NDF) digestibility of barley. Cyclotrichium niveum essential oil negatively affected end-products of rumen fermentation; the value of the measured rumen volatile fatty acids (VFA: acetate, propionate, butyrate, isobutyric acid, valerate and isovalerate) significantly decreased compared to the control group (P&amp;lt;0.001). Carbon dioxide and methane gases created as a result of incubation in rumen fluid were calculated using volatile fatty acid values formed in rumen fluid. The addition of Cyclotrichium niveum essential oil significantly reduces the CO2 in rumen fluid (P&amp;lt;0.001). Methane (CH4) gas from rumen fluid was significantly decreased in treatment groups compared the control group (P &amp;lt;0.001) While end-products of rumen fermentation parameters significantly decreased with all doses of Cyclotrichium niveum essential oil, rumen pH has increased (P&amp;lt;0.05). The results show that when the Cyclotrichium niveum essential oil incubated with barley significantly inhibited the rumen microbial activity and overall fermentation process of rumen.

Effects of barley type and processing method on rumen fermentation, dry matter disappearance and fermentation characteristics in batch cultures

The objective of this study was to investigate the effects of barley type (two-row versus six-row) and processing method (grinding, dry-rolling and temper-rolling) on processing quality, dry matter (DM) disappearance (DMD), and fermentation characteristics in batch culture. The study was a completely randomized design with 2 barley types × 3 processing methods in a factorial arrangement. Thirty barley cultivars/lines were selected from a set of 85 cultivars/lines that were previously screened for in vitro DMD. The mean DMD values (g/kg) were 328 (low), 520 (medium), and 688 (high) after 48 of incubation. Ten representative samples of each DMD group (low, medium and high) of two- and six-row barley were selected. Barley samples were ground (1-mm screen), and dry- or temper-rolled to a processing index (PI) of 0.80. Particle size distribution (PSD) of rolled barley across 4.00-, 3.35-, 2.36-, 1.18-, 0.85-mm sieves, gas production (GP) kinetics, DMD and fermentation traits at 6, 24 and 48 h of incubation were measured. Two-row had higher kernel weight, test weight, plumpness, starch and ether extract content, and lower fibre content than six-row barley (P < 0.01).The PSD of rolled barley was affected by barley type, processing and their interaction (P < 0.01). More (P < 0.01) coarse particles were retained on the 3.35-mm sieve for two-row versus six-row barley (dry-rolled, 0.44 versus 0.34; and temper-rolled, 0.91 versus 0.85). Compared to six-row, two-row barley had greater (P < 0.01) DMD after 6 and 48 h and greater (P = 0.02) crude protein disappearance (CPD) after 48 h. Ground barley had higher DMD, CPD, microbial N production and molar proportion of propionate and total VFA production than rolled barley (P < 0.01); whereas these variables did not differ between dry- and temper-rolled barley. A barley type × processing interaction for DMD, CPD and GP kinetics was identified (P < 0.01). Coarse particles were negatively, while fine particle were positively correlated with DMD (P < 0.01). These results indicate that although PSD of dry- and temper-rolled barley differed, impacts on GP and DMD were small, particularly for two-row barley. The differences in DMD at 6 or 48 h between two- and six-row barley suggest that barley type can impact both the rate and extent of barley digestion in the rumen. These differences suggest that there is considerable opportunity to select barley varieties based on responses to processing and ultimately their feed value for ruminants.

Visualization of spatial gene expression in plants by modified RNAscope fluorescent in situ hybridization

BackgroundIn situ analysis of biomarkers such as DNA, RNA and proteins are important for research and diagnostic purposes. At the RNA level, plant gene expression studies rely on qPCR, RNAseq and probe-based in situ hybridization (ISH). However, for ISH experiments poor stability of RNA and RNA based probes commonly results in poor detection or poor reproducibility. Recently, the development and availability of the RNAscope RNA-ISH method addressed these problems by novel signal amplification and background suppression. This method is capable of simultaneous detection of multiple target RNAs down to the single molecule level in individual cells, allowing researchers to study spatio-temporal patterning of gene expression. However, this method has not been optimized thus poorly utilized for plant specific gene expression studies which would allow for fluorescent multiplex detection. Here we provide a step-by-step method for sample collection and pretreatment optimization to perform the RNAscope assay in the leaf tissues of model monocot plant barley. We have shown the spatial distribution pattern of HvGAPDH and the low expressed disease resistance gene Rpg1 in leaf tissue sections of barley and discuss precautions that should be followed during image analysis.ResultsWe have shown the ubiquitous HvGAPH and predominantly stomatal guard cell associated subsidiary cell expressed Rpg1 expression pattern in barley leaf sections and described the improve RNAscope methodology suitable for plant tissues using confocal laser microscope. By addressing the problems in the sample collection and incorporating additional sample backing steps we have significantly reduced the section detachment and experiment failure problems. Further, by reducing the time of protease treatment, we minimized the sample disintegration due to over digestion of barley tissues.ConclusionsRNAscope multiplex fluorescent RNA-ISH detection is well described and adapted for animal tissue samples, however due to morphological and structural differences in the plant tissues the standard protocol is deficient and required optimization. Utilizing barley specific HvGAPDH and Rpg1 RNA probes we report an optimized method which can be used for RNAscope detection to determine the spatial expression and semi-quantification of target RNAs. This optimized method will be immensely useful in other plant species such as the widely utilized Arabidopsis.

Effects of high moisture airtight storage of barley with exogenous enzymes on phosphorus digestibility of barley fed to pigs alone or in combination with soybean meal

The aim was to study the effect of storage (high moisture airtight (HMA) storage vs. dry storage) and a combination of phytase, xylanase, β-glucanase, and protease on nutrient solubility and digestibility of barley. Experiment 1 studied the effect of HMA stored barley at 29%, 35%, and 40% moisture and enzyme combination to define the optimum moisture level for the maximum nutrient solubility of barley. The ‘35% moisture’ was chosen for HMA storage of barley because this treatment (without or with enzymes) enhanced phytate degradation (31–73%) and the solubility of P (125–177%), nitrogen (N) (95–125%) and protein (56–68%) compared to dry storage (P < 0.05) and at the same time seemed to prevent a loss of energy and N (ammonia) by microbial fermentation. In Exp. 2, 6 female growing pigs (43 ± 2 kg) were used per diet (8 diets, 48 pigs) in a 12-d nutrient digestibility study to assess the effect of HMA stored barley at 35% moisture and enzyme combination on coefficient of total tract apparent digestibility (CTTAD) of P in barley fed alone or together with soybean meal (SBM). Also, HMA storage of barley at ‘35% moisture’ without and with enzyme combination enhanced phytate degradation (43–58%) and P solubility (2.5–3.3 fold) (P < 0.05). Thus, HMA stored barley (solely endogenous enzymes) enhanced CTTAD of P to almost the same extent as dry stored barley with enzyme combination (endogenous enzymes plus added enzymes) in the barley diet (45–49%) and the barley-SBM diet (15–25%) (P < 0.05). Adding the enzyme combination to HMA stored barley achieved the greatest increase of CTTAD of P in the barley diet (70%) and the barley-SBM diet (36%) (P < 0.05). The inclusion of the enzyme combination to HMA stored barley tended to enhance the calculated CTTAD of P of SBM (29%) compared with no enzyme combination (P = 0.06) due to the lower endogenous enzymes activity in HMA stored barley. It is necessary to add the enzyme combination to enhance P digestibility of SBM when fed together with HMA stored barley. Overall, HMA storage with enzyme combination is a potential method to enhance P digestibility of barley in pigs to reduce the dietary need for inorganic P addition and P excretion to the environment.

In situ ruminal digestibility of red osier dogwood in finishing beef heifers

An in situ study was conducted to determine the effect of feeding red osier dogwood (ROD) on ruminal digestion of barley, ROD, and barley silage in beef heifers. Heifers were fed diets that varied by substituting ROD for barley silage at 0%, 3%, 7%, or 10%. Slowly degradable fraction and effective degradability (ED) of ROD crude protein (CP) linearly (P &lt; 0.02) increased with increasing ROD. The ED of CP of barley and barley silage was reduced (P &lt; 0.01) by feeding ROD. These results indicate that feeding ROD potentially reduces ruminal protein degradability, thereby improving protein efficiency.

Lactobacilli Are Prominent Members of the Microbiota Involved in the Ruminal Digestion of Barley and Corn.

The chemical composition of barley grain can vary among barley varieties (Fibar, Xena, McGwire, and Hilose) and result in different digestion efficiencies in the rumen. It is not known if compositional differences in barley can affect the microbiota involved in the ruminal digestion of barley. The objective of this study was to characterize the in situ rumen degradability and microbiota of four barley grain varieties and to compare these to corn. Three ruminally cannulated heifers were fed a low (60% barley silage, 37% barley grain, and 3% supplement) or high grain (37% barley silage, 60% barley grain, and 3% supplement) diet. One set of bags was used to estimate dry matter (DM), starch and crude protein (CP) degradability. A second set was used to extract DNA from the adherent microbiota and visualize grain after incubation using scanning electron microscopy (SEM). DNA was subjected to amplicon 16S rRNA gene sequencing followed by analysis using QIIME. In the low grain diet, McGwire had the highest effective degradability (ED) of DM (P < 0.01). The ED of starch was highest (P < 0.01) for Fibar, McGwire, and Xena, but the ED of CP was not affected by variety. For the high grain diet, Xena and McGwire had the highest ED of DM (P < 0.01). The ED of starch was highest (P < 0.01) for Xena and Fibar. The ED of protein was highest (P < 0.01) for Xena and McGwire. Although the microbiota did not differ among barley varieties, they did differ from corn and with incubation time. Lactobacilli were dominant members of the mature biofilms associated with corn and barley and were accompanied by a notable increase in the lactic acid utilizing genera, Megasphaera. As none of the cattle exhibited subclinical or clinical acidosis during the study, our results suggest that lactobacilli play a more prominent role in routine starch digestion than presently surmised.

Comparative energy content and amino acid digestibility of barley obtained from diverse sources fed to growing pigs.

ObjectiveTwo experiments were conducted to determine the content of digestible energy (DE) and metabolizable energy (ME) as well as the apparent ileal digestibility (AID) and standardized ileal digestibility (SID) of crude protein (CP) and amino acids (AA) in barley grains obtained from Australia, France or Canada.MethodsIn Exp. 1, 18 growing barrows (Duroc×Landrace×Yorkshire; 31.5±3.2 kg) were individually placed in stainless-steel metabolism crates (1.4×0.7×0.6 m) and randomly allotted to 1 of 3 test diets. In Exp. 2, eight crossbred pigs (30.9±1.8 kg) were allotted to a replicate 3×4 Youden Square designed experiment with three periods and four diets. Two pigs received each diet during each test period. The diets included one nitrogen-free diet and three test diets.ResultsThe relative amounts of gross energy (GE), CP, and all AA in the Canadian barley were higher than those in Australian and French barley while higher concentrations of neutral detergent fiber, acid detergent fiber, total dietary fiber, insoluble dietary fiber and β-glucan as well as lower concentrations of GE and ether extract were observed in the French barley compared with the other two barley sources. The DE and ME as well as the SID of histidine, isoleucine, leucine and phenylalanine in Canadian barley were higher (p<0.05) than those in French barley but did not differ from Australian barley.ConclusionDifferences in the chemical composition, energy content and the SID and AID of AA were observed among barley sources obtained from three countries. The feeding value of barley from Canada and Australia was superior to barley obtained from France which is important information in developing feeding systems for growing pigs where imported grains are used.

In situ identification and quantification of protein-hydrolyzing ruminal bacteria associated with the digestion of barley and corn grain.

In this study, BODIPY FL DQ™ casein staining combined with fluorescence in situ hybridization (FISH) was used to detect and identify protein-hydrolyzing bacteria within biofilms that produced active cell-surface-associated serine- and metallo-proteases during the ruminal digestion of barley and corn grain in cows fed barley-based diets at 2 different levels. A doublet coccoid bacterial morphotype associated with barley and corn grain particles fluoresced after BODIPY FL DQ™ casein staining. Bacteria with this morphotype accounted for 3%-10% of the total bacteria attached to surface of cereal grain particles, possibly indicative of an important role in the hydrolysis of the protein matrix within the endosperm. However, the identity of these predominant proteolytic bacteria could not be determined using FISH. Quantitative FISH revealed that known proteolytic species, Prevotella ruminicola, Ruminobacter amylophilus, and Butyrivibrio fibrisolvens, were attached to particles of various cultivars of barley grain and corn, confirming their role in the proteolysis of cereal grains. Differences in chemical composition among different barley cultivars did not affect the composition of proteolytic bacterial populations. However, the concentrate level in the basal diet did have an impact on the relative abundance of proteolytic bacteria and thus possibly their overall contribution to the proteolysis of cereal grains.

Partial dehulling increases the energy content and nutrient digestibility of barley in growing pigs.

ObjectiveThe hull attached to the barley kernel can be mechanically removed thus reducing the fiber content of the barley. This experiment was carried out to evaluate the effects of partial dehulling on the nutrient digestibility as well as the digestible energy (DE) and metabolizable energy (ME) content of barley in pigs.MethodsTwo hulled barley samples (high fiber barley [HF] and low fiber barley [LF]) with either high or low fiber contents were obtained from the Hubei and Jiangsu Provinces of China. A portion of the two barleys was mechanically dehulled (dehulled high fiber barley [DHF] and dehulled low fiber barley [DLF]). Thirty barrows (initial BW = 31.5±3.2 kg) were assigned to one of five diets in a randomized complete block design. The five diets consisted of 96.9% corn, HF, LF, DHF, or DLF supplemented with 3.1% minerals and vitamins. Each diet was fed to six barrows housed in individual metabolism crates for a 10-d acclimation period followed by a 5-day total but separate collection of feces and urine.ResultsThe daily loss of gross energy (GE) in feces was lower (p<0.01) for pigs fed DHF than for those fed HF. The daily N intake and fecal N loss were lowest (p<0.01) for pigs fed the corn diet. The DE and ME as well as the apparent total tract digestibility (ATTD) of dry matter, GE, organic matter, neutral detergent fiber (NDF) and acid detergent fiber (ADF) of DHF or DLF were higher (p<0.01) than the values in HF and LF, respectively while the values except the ATTD of NDF and ADF in DLF were higher (p<0.01) than the values in DHF and were comparable to corn.ConclusionThe DE and ME contents as well as the ATTD of nutrients in both DHF and DLF barley were improved compared with the HF and LF barley. Moreover, the nutritive value of DLF barley was comparable to the yellow-dent corn used in the study.

Expression of an Aspergillus niger xylanase in yeast: Application in breadmaking and in vitro digestion

The cDNA of the β-1,4-endoxylanase of Aspergillus niger US368 was cloned and expressed in Pichia pastoris under the constitutive GAP promoter. The maximum activity obtained was 41UmL−1, which was about 3-fold higher than that obtained with the native species. The purified enzyme showed a specific activity of 910Umg−1 and a molecular mass of 24kDa. It had an optimal activity at pH 4 and 50°C, stable in a wide range of pH and in the presence of some detergents and organic solvents. r-XAn11-His6 (recombinant xylanase) was used as an additive in breadmaking. A decrease in water absorption, an increase in dough rising and improvements in volume and specific volume of the bread were recorded. The r-XAn11-His6 was also used in in vitro digestion of barley and wheat bran leading to a decrease of the viscosities and an increase of the reducing sugars and total sugars contents.

Effect of replacing barley with wheat grain in finishing feedlot diets on nutrient digestibility, rumen fermentation, bacterial communities and plasma metabolites in beef steers

This study investigated the effect of substituting barley grain with wheat on rumen fermentation, bacterial communities, nutrient digestibility and plasma metabolites in finishing feedlots steers. The experiment was designed as a replicated 4×4 Latin square with 8 rumen cannulated steers (742±44kg) fed diets in which wheat was substituted for 0, 30%, 60% or 89% of barley grain dry matter (DM). All grains were dry-rolled to a processing index (PI) of 80% expressed as a percentage of volume weight of processed grain divided by the volume weight of unprocessed grain. The remaining dietary ingredients consisted of 6% barley silage and 5% supplement. Duration of pH below 5.8 linearly increased (P=0.04) with increasing levels of wheat, whereas average, minimum and maximum pH as well as the time and area under pH 5.5 (P=0.08) and 5.2 (P=0.18) did not differ among diets. Likewise, volatile fatty acids (VFA) profiles, concentrations of VFA, ammonia, numbers of protozoa and total tract digestibility of nutrients were unaffected (P>0.05) by this substitution. Increasing levels of wheat linearly increased copy numbers of 16S rRNA for total bacteria (P=0.01) and Ruminococcus amylophilus (P=0.04) per g of rumen contents. Inclusion of wheat in the diet linearly reduced plasma albumin (P=0.03) and urea nitrogen (P=0.01) concentrations, but did not affect (P>0.05) other major plasma metabolites. In conclusion, replacing barley grain with wheat in the diets of feedlot steers had little negative impact on nutrient digestibility or rumen fermentation, however, it increased the daily duration that rumen pH remained below 5.8. These data suggest that there is little difference in the ruminal fermentation or digestibility of barley vs wheat if both grains are processed to a similar degree.

Effects of volume weight, processing method and processing index of barley grain on in situ digestibility of dry matter and starch in beef heifers

The objectives of this study were to evaluate the effects of volume weight (VW; g/L), processing method (PM; control vs. precision processing [PP]), and processing index (PI; VW after rolling/VW before rolling) of barley grain on in situ ruminal kinetics and in vitro intestinal digestion. The study was designed as a 2×2×2 factorial arrangement of treatments: VW (low vs. high), PM (control vs. PP) and PI (0.75 vs. 0.85). Ten barley samples, 5 low (580g/L) and 5 high (680g/L) VW, were either dry-rolled with a single roller setting (control) or screened into two fractions of small or large kernels using a 4-mm sieve, and then dry-rolled (i.e., PP). Each sample was dry-rolled moderately or coarsely with PI of 0.75 or 0.85. Three beef heifers (650±25.5kg body weight) fitted with rumen cannulas and fed a diet consisting of 700g/kg barley silage and 300g/kg concentrate mix (dry matter [DM] basis) were used for the in situ study. In situ degradation kinetics of DM and starch were estimated after 0, 3, 6, 12, 24 and 48h of ruminal incubation. Data from DM and starch degradation at different times of incubation were fitted to a model y=a+b(1−e−c(t−L)). in vitro intestinal disappearances of DM and starch of ruminal residue after 12h of incubation were determined using a modified three-step procedure. Interactions between VW and PM on effective degradability (ED; P<0.01) and between PM and PI on the degradation kinetics (P<0.05) were observed. The VW of barley grain did not affect the degradation kinetics of DM and starch whereas ED of DM was greater (P<0.01) in high versus low VW in the control samples. For in situ DM disappearance, a (P<0.01) and b (P<0.07) fractions were lower, but c and ED were higher (P<0.01) in PP versus control samples. Increased processing of barley consistently resulted in greater (P<0.01) values of degradation kinetics and ED compared with less processed barley. Intestinal DM disappearance of rumen residues was affected by all three factors (VW, PM and PI). Regression results showed that the rate of DM disappearance was correlated to the particle size distribution and the fine particles were the primary predictor. The results demonstrated that the PP approach and manipulating PI are effective ways to optimize rumen digestion of barley grain. This suggests that a concise and reliable method to predict rumen digestion of barley may be developed based on measuring the fines content of processed barley.

In vivo digestibility of two different forage species inoculated with arbuscular mycorrhiza in Mediterranean red goats

The aim of this study was to evaluate the effect of field inoculation with arbuscular mycorrhiza spp. (AM) on the forage quality and in vivo digestibility of barley (Hordeum vulgare L.) and berseem clover (Trifolium alexandrinum L.) obtained using no external inputs. In November 2011 two plots were used for each species: one sown with seeds inoculated with AM and the other one with seeds not inoculated. For both forage species the following constituents were determined: crude protein (CP), crude fiber (CF), ether extract, neutral detergent fiber (NDF), acid detergent fiber (ADF), acid detergent lignin (ADL), ash, Ca and P. In vivo digestibility of barley and berseem clover was evaluated in Mediterranean red dairy goats. Twenty-eight mature goats were randomly assigned to four groups, homogeneous for age (2.5 years) and body weight (43.3kg), and received the fresh forages as follows: Mycorrhized barley group (MBG), Control barley group (CBG), Mycorrhized clover group (MCG) and Control clover group (CCG). Barley and berseem clover were given fresh ad libitum. The experimental period started after 15 days of adaptation and lasted 7 days. Coefficients of organic matter (OM), CP, CF, NDF and ADF in vivo digestibility were measured by using acid insoluble ash as internal indigestibility marker. Mycorrhized barley showed an increase in CP and a reduction in ADF and ADL concentrations. In addition, a significant effect of AM field inoculation on barley digestibility was observed. The MBG showed a significant increase of the following digestibility coefficients in comparison with CBG: CF (P<0.01), CP, NDF and ADF (P<0.001). Conversely, only OM and ADF digestibility coefficients of berseem clover were increased by mycorrhization (P<0.05). Our results showed that the inoculation with AM was able to improve the quality and enhance the in vivo digestibility of barley grass offered to mature goats, whereas only minor effects were observed on berseem clover quality and digestibility.

Effect of barley and oats on feed intake, live weight gain and some carcass characteristics of fattening lambs

The influence of whole, crushed and ground barley and oats on intake, performance and carcass characteristics of lambs was examined. A comparison of diets was conducted with individually-fed male and female lambs in six groups. The study was repeated in three successive years (1995–1997) using the same experimental design. A total of 192 lambs of a mean initial age of 74 days (SD 13.0) and live weight 20.6kg (SD 4.54) were daily fed their respective concentrates, 72g dry matter (DM)/kg metabolic live weight (kgW0.75), for 98 days from weaning to slaughter. Hay was provided ad libitum.The lambs adapted more quickly to diets containing barley than to those containing oats. Compared to oats, the total daily DM intake was higher on barley (1162 vs. 990g DM/lamb, 89 vs. 78g DM/kgW0.75, P<0.001). Hay consumption was significantly lower on oats than on barley (182 vs. 344g DM/day, P<0.001). On oats the lambs experienced energy and protein deficiencies with their energy and protein intakes being 20% below feeding recommendations. On the barley diets the energy and protein requirements of the lambs were satisfied. When processed cereals were offered, there was no increase in the total DM, energy or protein intakes. Processing did not improve the organic matter digestibility of barley or oats.The growth rate (P<0.01), carcass weight (P<0.001) and slaughter percentage (P<0.001) were higher on a barley diet than on oats. A barley diet resulted in more kidney fat (P<0.01) and fattier carcasses. Processing had no positive influence on the live weight gain. On the contrary, lambs receiving crushed or ground barley or oats had a lower final live weight than those receiving whole grains (P<0.001). The utilisation of whole grain was more efficient than that of processed grain. There were no advantages in processing barley and oats for the feeding of lambs.

Amino Acids and Protein Digestibility and Metabolizable Energy Availability of Barley Ration in Response to Grind® Enzyme in Broiler Chickens

Increasing accuracy of broiler diet formulation based on amino acid digestibility in comparison to application of total amino acids could lead to more feed efficiency and productivity. This experiment was conducted for determination of sampling site (excreta and ileum) and recognition of the effects of a commercial enzyme (Grind ® ; Danisco, Finland) on metabolizable energy, protein and amino acid digestibility of barley. This study was modulated by a marker in 21-day old Arbor Acres chickens. Corn-soybean meal was used as a control diet and, in the other two treatments, barley (at a level of 40%) with and without enzyme as the test ingredient were supplemented to the basal diet. Chromic oxide was included in all diets (0.5%) as an indigestible marker. Apparent metabolizable energy (AME), corrected by nitrogen (AMEn) and apparent digestibility of aspartic acid, glutamic acid, serine, glycine, alanine, tyrosine, valine and methionine were significantly (p<0.05) higher in feces than ileum. Protein digestibility of diet and barley was significantly (p<0.05) higher in the ileum than in feces. Apparent digestibility of tryptophan, proline, methionine, phenylalanine and lysine was increased significantly (p<0.05) by enzyme supplementation. In contrast, no response was observed in AME, AMEn, and protein digestibility of the diet and barley by enzyme supplementation. The results of this study have shown that AME and amino acid digestibility were increased in feces, in contrast an adverse effect was observed for protein digestibility of the diet and barley.

An investigation of carbohydrate and protein degradation ratios, nitrogen to energy synchronization and hourly effective rumen digestion of barley: effect of variety and growth year

The objective of this study was to investigate rumen available soluble, insoluble and total protein (CP), estimated structural (SC) and non-structural carbohydrate (starch: ST), degradation characteristic ratios and hourly effective degradation of six barley varieties during three consecutive growth years (2003, 2004, 2005). The magnitude of the differences was determined between the varieties and growth years. Measured degradation kinetics included soluble fraction (S), undegradable fraction (U), lag time (T(0)) and rate of degradation (K(d)) of the insoluble but degradable fraction (D). Rumen available soluble, insoluble, and total N, SC and ST and the rumen degradation characteristic ratios were determined using the Tamminga rumen degradation ratio system. Characteristics of the hourly effective degradation between N and carbohydrate (CHO) among the six barley varieties for 3 years were also studied. The degradation ratios included were total rumen available N and carbohydrate ratio (FN/FCHO), rumen available soluble N and carbohydrate ratio (SN/SCHO), and rumen available insoluble N and carbohydrate ratio (EN/ECHO). Results show that both the barley variety and growth year had a significant effect on degradation kinetics (S, D, U, T(0) and/or K(d)). Differences in the ratio of FN/FCHO among varieties ranged from 16.6 to 19.0 g/kg (p < 0.01). There was no difference in SN/SCHO (p > 0.05) with an average of 4.9 g/kg. The difference in the EN/ECHO ratio tended to be significant among the varieties (p = 0.069) ranging from 18.4 to 21.3 g/kg. Differences in the hourly effective degradation between N and CHO were relatively small at shorter incubation times (2-4 h) However, as the length of rumen incubation increased (12-24 h), much larger differences in the rate of effective hourly degradation were observed. In conclusion, both barley variety and growth year had significant effects on rumen degradation kinetics. The mean FN/FCHO ratio of 17.2 (16.6-19.0) was observed for the six barley varieties in this experiment. All barley varieties exhibited a less optimal rumen fermentation ratio (17.2 < optimum: FN/FCHO = 25 to 33 g N per kg CHO). The large differences in the degradation kinetics, characteristics ratios and hourly effective degradation among barley varieties and growth years may help to explain some of the large variations that are seen in cattle performance.

Prediction of in vivo apparent total tract energy digestibility of barley in grower pigs using an in vitro digestibility technique1

The DE content within cereal grains can vary 25% mainly due to changes in apparent total tract digestibility (ATTD) of energy. In vitro digestibility techniques have been developed to predict the DE value among feedstuffs. However, these techniques have not been tested properly for their suitability to predict the variation in energy digestibility and DE content within a cereal grain. The objective of the present study was to establish and evaluate an in vitro digestibility technique to predict in vivo ATTD of energy of barley in grower pigs. Barley grain samples (hulled, n = 21) with a large range in quality were collected; the ADF and CP content ranged from 4.5 to 11.4% and 10.0 to 16.4% (DM basis), respectively. The ATTD of energy was determined using barrows (n = 63, 33 +/- 2.1 kg of initial BW) in 2 periods with 6 observations per sample and ranged from 51.9 to 78.5%, with relative errors between 0.4 and 5.0%. A preliminary study, comparing a 2- and a 3-step in vitro digestibility technique using 3 barley samples, indicated that R(2) between in vivo and in vitro energy digestibility was greater using the 3- than the 2-step technique (0.92 vs. 0.76). Therefore, the 3-step in vitro digestibility technique was used solely in subsequent analyses. Briefly, ground barley was subsequently incubated with pepsin for 6 h, pancreatin for 18 h, and cellulase for 24 h. The DM and GE content of samples and residues were measured to calculate digestibility. The in vitro energy digestibility of the 21 barley samples with duplicate measurements ranged from 63.7 to 82.2%, with relative errors between 0.1 and 2.6%. In vitro energy digestibility was strongly related (y = 1.25 x - 25.22; R(2) = 0.81) to in vivo energy digestibility. Finally, a subset of 7 barley samples was analyzed in quadruplicate using the 3-step in vitro technique. The relationship between in vitro and in vivo energy digestibility was very strong (y = 1.23 x - 25.33; R(2) = 0.97) with relative errors between 0.5 and 2.7%. In vitro DE and energy digestibility were perfectly related (R(2) = 1.00). In summary, the 3-step in vitro energy digestibility technique can accurately predict the ATTD of energy in barley in grower pigs. The 3-step in vitro digestibility technique, thus, might be useful as the reference laboratory procedure to calibrate analytical equipment to rapidly predict the ATTD of energy in barley.

Intake, digestibility and rumen characteristics in cattle offered whole-crop wheat or barley silages of contrasting grain to straw ratios

The effects of varying the grain (G) to straw (S) ratio (G:S) of whole-crop wheat and barley silages on intake and digestibility and whole-crop barley silage on rumen fermentation characteristics were examined in two parallel studies. For the intake and digestibility study, eight Aberdeen Angus cross-bred steers (mean bodyweight 407 kg (S.D. 24.2)) were used in two (barley and wheat) 4 × 4 Latin Square designed experiments. The dietary treatments were four G:S ratios: 0:100, 30:70, 60:40 and 90:10. Intake of grain linearly increased ( P<0.001) while that of straw decreased ( P<0.001) as the ratio of G:S increased for both cereals. No effect ( P>0.05) was observed in total dry matter (DM) intake (DMI) or in DMI per kg liveweight. There was a positive linear ( P<0.001) effect on the digestibility of the DM and organic matter (OM) and a negative linear effect on neutral detergent fibre (aNDFom) digestibility ( P<0.01) as the G:S ratio increased for both cereals. Both a positive linear ( P<0.05) and quadratic ( P<0.01) effect were observed for the G:S ratio on nitrogen (N) digestibility of barley and a corresponding positive linear increase ( P<0.01) for wheat. A negative linear effect was found for digestibility of starch ( P<0.01) and a positive linear effect for faecal grain content ( P<0.01) with increasing G:S ratio. Four Holstein–Friesian steers (mean bodyweight 659 kg (S.D. 56.9)) fitted with rumen cannulae were used in the rumen study. A negative linear effect of G:S ratio was found on rumen pH ( P<0.001) while a positive linear effect was found on rumen ammonia ( P<0.001) and total volatile fatty acid (VFA) concentration ( P<0.01) with increasing G:S ratio. A negative linear effect ( P<0.01) was found on the molar proportion of acetic acid. However, this decrease was offset by linear increases in the molar proportions of iso- and n-butyric acid, iso- ( P<0.01) and n- ( P<0.05) valeric acid, and to a lesser extent in propionic acid ( P<0.01). No effect of treatment was found on rumen pool sizes of DM or its constituents. A positive linear effect ( P<0.01) was found on the effective degradability (ED) of the DM, OM, N and starch while it was found to be negative in aNDFom ( P<0.05). No effect ( P>0.05) was found on the fractional clearance rates of DM, OM, aNDFom or starch or on liquid passage rate. It is concluded that increasing the G:S ratio in whole-crop wheat or barley silage linearly increased the intake of digestible nutrients for both wheat and barley and increasing the G:S ratio for whole-crop barley increased the concentration of fermentation products (total VFA, ammonia and the molar proportions of the VFAs, except acetic acid) in the rumen.