The influence of the variety of barley and level of nitrogen fertilisation on the digestibility and metabolisable energy value of barley meal in the pig

Metabolism studies were carried out with 45 kg pigs to examine barley meal from the varieties Golden Promise, Maris Mink, Lami, Zephyr and Abacus, all with similar nitrogen (N) content, and barley meal from the variety Zephyr which had received four different levels of N fertilisation. There were no significant differences (P > 0.05) between varieties for the apparent digestibility coefficients of gross energy (GE) and proximate constituents, the least significant difference for GE and N being 0.025 and 0.089 of the respective means. The mean digestible energy (DE) and metabolisable energy (ME) values were 14.48 and 14.07 MJ/kg dry matter (DM). The mean apparent digestibility of N was 0.685. The apparent digestibility coefficients of GE and N of meal from the variety Zephyr increased with N content. The increase in DE value with N content could be attributed to the increase in N digestibility.     

Cell-wall constituents of some grass species and varieties

Structural carbohydrates and lignin were determined in two varieties each of perennial ryegrass, cocksfoot and timothy during first growth. Structural carbohydrates were extracted with N-sulphuric acid and with 72% sulphuric acid and partitioned by paper chromatography. The content of structural constituents increased and in vitro digestibility decreased as the grasses matured. When compared at the same growth stage, perennial ryegrass varieties were higher in digestibility and lower in lignin than the other grasses. When compared at the same level of dry matter digestibility cocksfoot varieties were lower in structural carbohydrates but higher in lignin than other grasses. Correlations between digestibility and the content of structural constituents including fibre were highly significant. The results are discussed with reference to the effect of varietal variation in structural constituents on digestibility and voluntary intake.     

Cassava varietal screening for cooking quality: Relationship between dry matter,starch content,mealiness and certain microscopic observations of the raw and cooked tuber

Thirteen cassava (Manihot esculenta L Crantz) varieties from three successive annual harvests were screened for the mealiness of the cooked tuber, and the elasticity and smoothness of the pounded paste. Six were selected for further studies based on their mealiness and the starch and dry matter contents were determined. The diameter of the starch granules of the selected varieties and those of an irradiated M₁ V₂ population were measured. Microscopic examinations of the raw and cooked cells of the irradiated M₁ V₂ population were made. Correlations among all the parameters were studied. Varietal and seasonal differences in cooking quality were observed. There was no consistent relationship between mealiness of the boiled tuber and the elasticity and smoothness of the pounded paste. Varieties that were mealy were high in dry matter and starch content. The starch granules of mealy varieties were larger than those of nonmealy ones. There were no differences between mealy and non-mealy varieties in the arrangement of the cells or ‘cell condition’, of the raw tubers. However, the cells of the cooked tubers were held less cohesively, ie there was more ‘cell disorganisation’, in mealy varieties than in non-mealy ones.     

The potential of sunflower as a crop for ensilage

The chemical composition and nutritive value of sunflower, cv. Armavirec, was examined at 12 stages of growth. Maximum yield of dry matter (18.2 t ha^?1) occurred at the dough seed stage. Ether extract showed a five-fold increase with the development of the seed. This increase was reflected in the gross energy value which was maximal at 19.1 MJ kg^?1 dry matter at the dough seed stage. In-vitro organic matter digestibility was highest at the onset of flowering when the estimated metabolisable energy value was 10.5 MJ kg^?1 dry matter. Throughout the sampling period the calcium to phosphorus ratios varied from 3.9-5.9:1, an imbalance which would have to be redressed on diets based largely on sunflowers. Fresh and wilted sunflowers were successfully ensiled at the flowering stage, without the use of additives. pH values of the resulting silages were 3.86 and 4.01. The silages were each fed to six cross-bred wethers and voluntary dry matter intakes were 23.9 and 26.5 g kgW^?1 for the fresh and wilted silages respectively. For the fresh silage, intakes of digestible organic matter and digestible nitrogen were 612 and 13.6 g day^?1 compared with 684 and 16.7 g day^?1 for the wilted silage. Nitrogen retention increased with increase in silage dry matter. The optimum time of cutting for yield of nutrients is at the milky ripe stage. The composition of the crop at this stage should facilitate a satisfactory preservation by ensiling. The crop provides a high yield of dry matter over about 10 weeks in late summer and could provide a valuable standby forage crop for grass in dry areas.     

Effect of aqueous ammonia and other alkalis on the in-vitro digestibility of barley straw

The in-vitro digestibility of the organic matter of unground barley straw was increased by approximately 14 units by treatment with aqueous ammonia for 1 week at 20°C. Longer treatment times of 4 and 13 weeks had little or no additional effect on digestibility. Treatment with sodium hydroxide or tetramethylammonium hydroxide increased digestibility by up to 22 units. The content of cell walls of the straw after treatment with any of the alkalis was lower than that of untreated straw and the degradability of the walls from alkali-treated straw was more than 85% greater than that of the walls from untreated straw. Alkali treatment of straw caused loss of p-coumaric, ferulic and diferulic acids from the cell walls, the loss being greater with the stronger alkalis. The loss of ferulic was greater than that of p-coumaric acid.     

Chemical composition,organic matter digestibility and fatty acid content of linseed (Linum usitatissimum L.) harvested at five stages of growth

BAKGROUND: The quality of forages changes according to the morphological stage and it is important to define the nutritive characteristics and fatty acid (FA) content of the crop during growth. That allows a choice of cutting time in order to optimise the uilisation of the forages and to identify new sources of polyunsatured fatty acids (PUFAs) for ruminants. Our aim was to study changes in the chemical composition, in vitro organic matter digestibility, gross energy, and FA content, of linseed (Linum usitatissimum L.) samples collected from the stem extension to the mature seed stage. RESULTS: The development of linseed quality during growth is characterised by a progressive increase in the fibrous fractions and a decrease in crude protein, ether extract, ash, and in vitro organic matter digestibility (IVOMD). The FA profiles in the plant were characterised by four dominant FAs: palmitic acid (PA, 16:0), stearic acid (SA, 18:0), linoleic acid (LA, 18:2n‐6) and α‐linolenic acid (ALA, 18:3n‐3). PA, SA and LA increased from the visible bud stage to mature seed stage, while ALA decreased, consequently the n‐6/n‐3 polyunsaturated FA ratio of the plant increased during growth. CONCLUSION: The chemical composition and FA profile of linseed is closely connected to the development of the plant. Forage with a good nutritive value and with a content of unsaturated FA that is suitable for herbivorous feeding is still obtained by harvesting green linseed at the brown capsule stage. Copyright © 2008 Society of Chemical Industry     

Variation in in vitro digestibility of barley protein.

In vitro digestibility of protein was measured with pepsin/pancreatin in 321 spring barley lines grown in the field. The variation in digestibility was far less than the variation in the protein content. A small environmental influence on the digestibility was found. Two entries had slightly impaired digestibilities; these findings were partially verified in a repeated field trial, but were not confirmed in vivo. In vitro digestibilities of barleys grown in pots at various N-levels were positively correlated with protein or hordein content. In vitro digestibility was negatively correlated with the fibre content in decortification fractions of Bomi and the high-lysine mutant Risø 1508. The digestibility was positively correlated with the hordein concentration for the Bomi fractions, but not for the 1508 fractions.     

Degradation rate and chemical composition of different types of alkali-treated straws during rumen digestion

The degradation in the rumen and change in chemical composition of untreated and four samples of alkali-treated barley straw were studied in farm-scale treatments with ammonia, ‘dry’ sodium hydroxide and two different aqueous sodium hydroxide systems. The alkali treatments increased the fraction soluble in organic solvents and decreased the lignin content (determined as Klason lignin). The amounts of cellulose and arabinoxylans were not significantly changed. The degree of rumen degradability increased with the order of alkaline treatment given above. The degradation rates of dry matter and the NDF fraction were parallel to each other but varied considerably with the treatments. The two most efficient aqueous alkaline treatments showed a degradation rate four times that of untreated straw. For these two samples the arabinoxylans were solubilised faster than cellulose during the first part of the incubation. In the other samples the degradation of arabinoxylans and cellulose ran almost parallel. During the rumen incubation the lignin content of the straw residues increased for all samples. There was an inverse relationship between the content of p-coumaric and ferulic acids on the degree of digestibility. A relationship between acetyl groups and digestibility was not found.     

Modified wood waste and straw as potential components of animal feeds

Beech, oak and poplar sawdusts and barley straw were modified by physical, chemical and fungal treatments and then evaluated for their possible usefulness as components of animal feeds by measuring their digestibility using a rumen liquor-acid pepsin in vitro method. The most successful modification of sawdust was achieved by fungal treatment with Fomes lividus followed by NaOH treatment. The apparent organic matter digestibility (o.m.d.) of beech was increased from 5 to 59, and of oak sapwood from 14 to 56. By the same treatments, the o.m.d. of straw was increased from 46 to 70.     

Ensilage of whole-crop barley. II.—Composition of barley and barley silage at different stages of growth

Samples of whole barley cv. Zephyr were cut at 7 stages of growth and after being chopped were ensiled in small laboratory silos. Changes in individual carbohydrates and organic acids during ensilage were studied. The water-soluble carbohydrates, which rose to a maximum (32.6% of the dry matter) at the milky kernels stage of growth, consisted mainly of fructosans with smaller amounts of fructose, glucose and sucrose. The main organic acid of the plant, malic acid, disappeared during ensilage. The practical significance of the changes is discussed.     

Effects of Dietary Crude Protein on Protein and Fat Deposition in Milk-Fed Veal Calves

Research on veal calf production has focused on maximizing lean tissue growth. Nevertheless, limited attention has been paid to the evolution of digestive and metabolic utilization of N and energy as calves get older, whereas age at slaughter increases. The objective of this study was to determine the effects of 4 concentrations of dietary crude protein (CP) content on protein and fat deposition and energy utilization in milk-fed calves at 3 stages of fattening using the balance technique combined with heat production measurements in a respiration chamber. At each stage, 16 Prim’Holstein male calves (mean body weight at each stage: 72, 136, and 212 kg) received 4 isocaloric diets with CP contents of 76, 88, 100, and 112% of a reference CP content fixed at 20% during the first stage and 19% during the 2 later stages. After 2 wk of adaptation to their respective diets and housing conditions, the calves were placed for 1 wk in an open-circuit respiration chamber for N and energy balance measurements (first 6 d) and measurement of the fasting heat production (last day). Measurements for a stage were performed over 2 periods of 4 successive weeks. There was no effect of dietary CP on digestibility during the 2 later stages, but the low-protein diet resulted in lower digestibility coefficients for dry matter, organic matter, gross energy, CP, and crude fat during the first stage. Endogenous fecal N was estimated as 2.5 g/kg of dry matter intake irrespective of stage, and metabolic urinary N was estimated at 0.07 g/kg of body weight^0.85 per day. Maximum N retention was 32.8, 40.5, and 44.0 g/d at stages 1, 2, and 3, respectively. The effect of protein intake on protein deposition was dependent on age of the calves, because the marginal efficiency of digestible protein utilization decreased from 64 to 18% as animals got older. Fat deposition decreased with increasing dietary CP content irrespective of stage. Total energy retention was not modified by dietary CP content. The composition of body weight gain was affected differently for each stage, because the protein content of body weight gain increased with increasing dietary CP content during the first stage, whereas it remained constant during the other 2 stages. Fat and energy content in body weight gain decreased with increasing dietary CP irrespective of stage. These results provide a basis for estimating protein requirement of veal calves according to a factorial approach.     

Application of tristimulus colorimetry to evaluate colour changes during the ripening of Colombian guava (Psidium guajava L.) varieties with different carotenoid pattern

The pigment composition of three Colombian guava varieties, Regional roja, Regional blanca, and Palmira ICA‐1, in unripe, turning and full ripe maturity stages was studied. Lycopene was identified as the major carotenoid of Regional roja and Palmira ICA‐1 (18.25 and 28.07 mg kg^?1 fruit, respectively in full ripe fruits) although a small amount of lutein was also found in the two varieties. β‐Carotene was only found in Palmira ICA‐1, whilst no detectable levels of carotenoids were found in the white‐fleshed guava (Regional blanca). A good correlation between the total carotenoid content and the colour parameters of guava peel was found, such that the Regional roja and Regional blanca varieties could be discerned by colour coordinates. The most remarkable differences were found when comparing the pulp colour.     

Composition and digestibility during ageing of consecutive leaves on the main stem of Italian ryegrass plants,growing undisturbed or regrowing after cutting

For modelling of grass digestibility throughout the growing season, the impact of cutting on individual leaves needs to be quantified. Therefore, a glasshouse experiment was carried out with Italian ryegrass (Lolium multiflorum Lam) grown from seed. Half of the plants were grown undisturbed until leaf stage 8, while the other half were cut at leaf stage 4, after which they were allowed to grow until leaf stage 9. The composition and digestibility characteristics of leaves 6, 7 and 8 on the main shoot of plants from both treatments were quantified. In the uncut plants, leaf blade length and mass and specific cell wall (CW) and organic matter (OM) mass (mg cm⁻²) was higher for consecutive leaves. During leaf ageing specific CW mass remained unchanged, while specific OM mass and CW digestibility declined, resulting in a decline of OM digestibility. CW digestibility of leaves decreased to c 78%, a value also found in an earlier experiment. The newly formed leaves after cutting had a reduced leaf size and specific leaf mass (SLM, mg DM cm⁻²). Leaf 6, that was damaged by cutting, showed a lower initial CW content and a rapid decline of specific CW and OM mass and of digestibility during ageing. Its low specific mass and digestibility of CW could have been related to cessation of CW synthesis during its growth after cutting, as was evidenced by the lower CW thickness of sclerenchyma cells. The later-formed leaves, 7 and 8, had digestibility characteristics similar to those of the uncut plants. Since leaf 6 hardly contributed to the total plant dry matter mass, the cut and the uncut plants differed only slightly in digestibility of the total leaf fraction. It can be concluded that cutting sets back leaf size and growth rate but has little effect on digestibility characteristics during ageing. © 1999 Society of Chemical Industry     

A cellulase digestion technique for predicting the dry matter digestibility of grasses

A digestion technique using a commercially-available crude cellulase preparation from Trichoderma viride is described. The enzyme showed cellulase, hemicellulase and proteolytic activity when tested on herbage or herbage polysaccharides. A high correlation (r = 0.92, P < 0.001, residual standard deviation 2.5) was found between a simple one stage enzyme digestion and in vivo dry matter digestibility for a range of grass species and varieties. In vitro dry matter digestibility and detergent fibre were also determined on the same samples and the results correlated with in vivo dry matter digestibility. The cellulase method is rapid and reproducible and particularly well suited for the evaluation of plant material in breeding programmes.     

Effect of including barley or molassed sugar beet feed in grass silage diets on their digestion by cattle and sheep

The objective of the experiment was to compare the digestion of barley, a starch-based feedingstuff, with molassed sugar beet feed (SBF), a high-fibre, sugar-containing feedingstuff, when fed to cattle and sheep receiving silage. There were between-species differences in rumen measurements. Sheep had higher mean daily rumen ammonia-N concentrations; the molar proportions (mmol mol^?1 total rumen volatile fatty acids) of propionic acid were higher and those of n-butyric acid lower in sheep than in cattle. The feeding of barley was associated with increased rumen populations of protozoa and increased rumen ammonia-N concentrations compared with the feeding of SBF. There were no significant differences between the diets fed in whole tract or rumen digestion of organic matter or nitrogen. However, feeding SBF tended to increase the quantities of non-ammonia-N and microbial N entering the small intestine daily: feeding barley did not improve N flow to the small intestine.     

Effect of barley and its amylopectin content on ruminal fermentation and nitrogen utilization in lactating dairy cows

The effect of type of grain (corn vs. barley) and amylopectin content of barley grain (normal vs. waxy) on ruminal fermentation, digestibility, and utilization of ruminal ammonia nitrogen for milk protein synthesis was studied in a replicated 3 × 3 Latin square design trial with 6 lactating dairy cows. The experimental treatments were (proportion of dietary dry matter): CORN, 40% corn grain, NBAR, 30% normal Baronesse barley:10% corn grain, and WBAR, 30% high-amylopectin (waxy) Baronesse barley:10% corn grain. All grains were steam-rolled and fed as part of a total mixed ration. The NBAR and WBAR diets resulted in increased ruminal ammonia concentrations compared with CORN (8.2, 7.4, and 5.6 mM, respectively), but other ruminal fermentation parameters were not affected. Ruminal digestibility of dietary nutrients and microbial protein synthesis in the rumen were also not affected by diet. Corn grain had greater in situ effective ruminal dry matter degradability (62.8%) than the barley grains (58.2 and 50.7%, respectively), and degradability of the normal barley starch was greater than that of the waxy barley (69.3 and 58.9%, respectively). A greater percentage of relative starch crystallinity was observed for the waxy compared with the normal barley grain. Total tract apparent digestibility of dry matter and organic matter were decreased by WBAR compared with CORN and NBAR. Total tract starch digestibility was greater and milk urea nitrogen content was lower for CORN compared with the 2 barley diets. In this study, the extent of processing of the grain component of the diet was most likely the factor that determined the diet responses. Minimal processing of barley grain (processing indexes of 79.2 to 87.9%) reduced its total tract digestibility of starch compared with steam-rolled corn (processing index of 58.8%). As a result of the increased ammonia concentration and reduced degradability of barley dry matter in the rumen, the utilization of ruminal ammonia nitrogen for microbial protein synthesis was decreased with the barley diets compared with the corn-based diet. In this study, waxy Baronesse barley was less degradable in the rumen and the total digestive tract than its normal counterpart. The most likely reasons for these effects were the differences in starch characteristics and chemical composition, and perhaps the different response to processing between the 2 barleys.     

Effects of harvest stage and re‐growth on yield,composition, ensilage and in vitro digestibility of new forage sorghum varieties

The effect of growth stage and re‐growth on the nutritional and ensilage characteristics of two new sorghum hybrids, BMR‐101 and Silobuster, and one commercial variety, FS‐5, was examined in this study. Varieties were sampled during the summer at the early heading (EH) stage and were harvested at the soft dough (SD) stage. Additional irrigation enabled autumn re‐growth and a second harvest. Plants of FS‐5 and BMR‐101 were resistant to lodging at EH. However, BMR‐101 and Silobuster suffered from high lodging at the SD stage of the summer harvest. Dry matter (DM) content of FS‐5 and BMR‐101 at EH was below 250 g kg^?1. DM yields of the varieties were similar at the summer harvest and higher than their respective re‐growth cuts. Ensilage DM losses were moderate and similar across varieties. Hemicellulose of SD plants was partly solubilised and most of the water‐soluble carbohydrate fermented, yielding lactic acid, ethanol and volatile fatty acids (VFA), and a pH < 4. In vitro DM digestibility of varieties was similar in summer silages, but lower in the respective re‐growth silages of FS‐5 and BMR‐101, reflecting the higher content of neutral detergent fibre and lignin in the re‐growth silages. The summer plus re‐growth cumulative yields of digestible DM of the respective FS‐5, Silobuster and BMR‐101 silages were 14.7, 16.6 and 14.5 t ha^?1. The commercial variety, FS‐5, may have some advantage over BMR‐101 and Silobuster owing to its relative resistance to lodging in addition to its high yield and good ensilage properties. Copyright © 2005 Society of Chemical Industry     

Metabolomic Profiling of Carotenoid Constituents in Physalis peruviana During Different Growth Stages by LC‐MS/MS Technology

With the current ongoing changes in global food demands, natural carotenoids are preferred by consumers and are gaining attention among food scientists and producers alike. Metabolomic profiling of carotenoid constituents in Physalis peruviana during distinct on‐tree growth stages was performed with liquid chromatography‐tandem mass spectrometry (LC‐MS/MS) technology. The results show that the β rings of β‐carotene are hydroxylated with great efficiency, and there is a continual synthesis of zeaxanthin at half‐ripe and full‐ripe stages, which is confirmed by relating the zeaxanthin content to that of its precursor (β‐carotene). Lutein was, in terms of mass intensity, the most abundant carotenoid constituent (64.61 µg/g at the half‐ripe stage) observed in this study. In addition, γ‐carotene, which is rare in dietary fruits and vegetables, was detected in the mature and breaker stages, albeit at a relatively low level. The results suggest that when we consider the variation in carotenoid content during different growth stages, Physalis peruviana can be considered a good source of natural carotenoids.     

Respiration rate,ethylene production and biochemical changes during fruit development and maturation of jujube (Ziziphus mauritiana Lamk)

Jujube fruits (Ziziphus mauritiana Lamk) of cv Zaytoni were harvested from fruit set until maturity to study some physiological and biochemical changes. Jujube fruit cv Zaytoni displayed a double‐sigmoid growth curve with a very short second stage (2 weeks). Changes in respiration rate and ethylene production during fruit development were typical of climacteric fruits, the peak of ethylene production coinciding with the climacteric rise in respiration. As for chemical constituents, reducing sugars were dominant and sucrose was absent in ripe fruit. Total soluble solid content was low during the early stages of growth, then increased to a peak in ripe fruit. Titratable acidity was low initially, but increased to a peak in physiologically mature fruit and declined rapidly in ripe fruit. The pattern of changes in protein content was typical of that characterising climacteric fruits. © 2002 Society of Chemical Industry