The digestibility and chemical composition of plant parts in Italian and perennial ryegrass during primary growth

Italian ryegrass (cv. S22) and perennial ryegrass (cv. S24) were sampled duringprimary growth at head emergence, pollen shedding and seed shedding in each of 2 years. Each sample was separated into approximately 19 plant parts and for each part the true dry matter digestibility, digestibility of cell wall and percentages of cell content, nitrogen, water-soluble carbohydrate and lignin were determined. Trends reported in the literature, based on a smaller number of plant parts, were generally confirmed, but were shown to conceal appreciable variation. Thus, while, on average, stem declined in digestibility faster than leaf sheath, the upper sheaths declined in digestibility faster than the lower internodes and nodes; similarly, the proportion of cell content declined at a rather similar rate to digestibility in leaf blade and much less than digestibility in stem but the position was reversed between pollen shedding and seed shedding in the case of dead leaf blade and internodes. While the N content of the inflorescence as a whole did not decline greatly with advancing maturity, the N content of the rachis was nearly halved. The upper part of the crop was more digestible than the lower part at head emergence, but not at seed shedding. Italian ryegrass had a higher proportion of cell content than perennial ryegrass in all types of plant part. The digestibility of cell wall declined with advancing maturity in all the plant parts examined. The lower portions of internodes had a higher proportion of cell content than the upper portions. There were gradients from top to bottom of the plant, e.g. percentage N declined and percentage water-soluble carbohydrate increased from top to bottom.     

Changes during growth in anatomical and chemical composition and in-vitro degradability of lucerne

Lucerne (alfalfa) was harvested at different stages of maturity and the plants classified according to a phenological scale. The main class was separated into anatomical parts and analysed for content of extractives and crude protein and in-vitro degradability. Whole crop samples were also analysed for polysaccharide residues, Klason lignin and in-vitro degradability of crude protein and polysaccharide residues. The composition of the plant changed during maturation with an increase of the stem fraction from 18.5% to 50.7% of dry matter and a corresponding decrease in the leaf fraction from 72.9% to 18.4% of dry matter. The leaf fraction changed least in content of extractives and crude protein and in-vitro degradability while in the stems all these paramaters decreased radically. Chemical analysis of residues after incubation with rumen liquor in vitro of whole crop samples revealed that the degradability of crude protein declined from about 90% to about 80% and of non-starch polysaccharides from about 90% to about 60% during maturation. Xylose was the least degradable polysaccharide residue at all harvests. Xylose residues also showed the greatest decrease in degradability during growth. A comparison showed that stage of development and harvest date were of practically equal value as predictor of crude protein content in lucerne.     

Nutrient elements in the herbage of white clover,red clover,lucerne and sainfoin

White clover, red clover, lucerne and sainfoin were grown in the field, and the mineral composition and cation/anion balance of the herbage were determined on samples taken at advancing stages of growth on eight occasions from 29 April to 18 July. The elements which showed the greatest differences in content between species were calcium, sodium, and molybdenum. White clover was consistently higher than the other species in nitrogen, phosphorus, chlorine and molybdenum. Sainfoin was consistently and substantially lower in calcium and sodium than the other species. Evidence based on the total contents of cations and inorganic anions and on determinations of ash alkalinity indicated that white clover and red clover had the highest contents of organic acids, sainfoin having substantially lower, and lucerne intermediate, levels.     

Chemical composition and in-vitro degradability of major chemical constituents of red clover harvested at different stages of maturity

The contents of extractives, starch, crude protein, non-starch polysaccharides and Klason lignin were determined in red clover harvested at six different stages of maturity. Chemical analysis of residues after incubation with rumen liquor in vitro revealed that the degradability of starch was 100% and of crude protein about 80% at all harvest times. The degradability of non-starch polysaccharides decreased from 76 to 51% during maturation and no degradation of Klason lignin was noticed. At all harvest times xylose was the least degraded non-starch polysaccharide residue followed by glucose and rhamnose. During maturation the greatest decrease in in-vitro degradability was noticed for the xylose residues followed by the glucose and the mannose residues.     

Amino acid composition and nutritional value of italian ryegrass,red clover and lucerne as influenced by application and content of nitrogen

In experiments with increasing applications of nitrogen to ryegrass, red clover and lucerne grown in pots, freeze-dried plant material with widely varying N-content was obtained. Increasing N-concentrations were associated with increasing nitrate contents which proportionally decreased the concentrations (g/16 g total-N) of all amino acids. Expressed as g amino acid/16 g total-N minus NO₃-N, concentrations of all amino acids were closely similar at different N-levels. Differences between the three species ' amino acid composition were negligible except for a lower concentration of lysine in the crude protein of ryegrass and of methionine + cystine in the crude protein of clover and lucerne. In feeding experiments with rats increasing total-N concentrations were generally associated with higher true digestibilities of the crude protein of ryegrass, red clover and lucerne, but slightly lower biological values, especially in red clover. Net crude protein utilisation was increased by increasing total-N concentration in ryegrass, decreased in red clover and unchanged in lucerne. When ranked according to the nutritional value of the crude protein, ryegrass comes first, lucerne second and red clover last. Addition of synthetic methionine to ryegrass and lucerne improved their biological values by 30 and 47% respectively.     

Changes during heating in chemical composition and in-vitro digestion of four commodities

The effects of duration of heating on the composition and digestibility of whole cotton seed, almond hulls, whole pressed safflower seed and alfalfa were studied. The four commodities were heated at 125°C from 0 to 120 h. Nitrogen and ash values were relatively stable across commodities and heating times. However, acid detergent fibre, neutral detergent fibre, in-vitro neutral detergent fibre remaining after 48 h fermentation and acid detergent insoluble nitrogen increased hyperbolically, approaching a relatively constant value at long heating times for all commodities. The sensitivity of each commodity to heat damage was different, and the rate that each analysis value approached a relatively constant value differed across commodities. In general, alfalfa was the most sensitive and whole cotton seed the least sensitive for a given nutrient change with heating time. Also the amount of neutral detergent fibre digested approached a relatively constant value at longer heating times for whole cotton seed, whole pressed safflower seed and alfalfa while approaching zero for almond hulls. Prior analysis of an unheated commodity is necessary to utilise compositional analyses to determine heat damage.     

The effect of a cellulase preparation derived from Trichoderma viride on the chemical changes during the ensilage of grass,lucerne and clover

Perennial ryegrass, lucerne and clover were each treated with formic acid (4.5 litre t^?1 crop) and a commercial cellulase preparation derived from Trichoderma viride (4 g kg^?1) and ensiled in triplicate in test-tube silos, capacity 80 g. The crops were minced, finely chopped or coarsely chopped before ensiling and the test-tubes were held at 0, 15, 35 or 50°C. All the silages were well preserved and the grass silages, with and without cellulase treatment, contained residual water-soluble carbohydrates. Treatment with the cellulase preparation resulted in more cellulose being hydrolysed in the grass silages than in the legume silages. The greatest losses of cellulose in each crop occurred in the minced silages held at 15 and 35°C.     

Chemical composition and in-vitro digestibility of thermochemically treated peanut hulls

Changes in chemical composition and digestibility of peanut hulls after a variety of thermochemical treatments were monitored. Mineral acids and base under elevated temperature (121°C) were generally ineffective for decreasing the fibrous, lignocellulosic component of the hulls. Only nitric acid-treatment effectively decreased the relative lignin content of the hulls. The lignin:nitrogen ratio and carbohydrate content of treated hulls were both highly correlated with in-vitro digestibility. Overall, thermochemical treatments did not increase the digestibility of peanut hulls.     

Chemical composition and in-vitro digestibility of biologically degraded peanut hulls

Changes in the chemical composition of peanut hulls inoculated with the white-rot fungus, Coriolus versicolor, the brown-rot fungus, Poria placenta, the imperfect mould, Trichoderma reesei, the bacterium Arthrobacter sp. KB-1, a mixture of the four organisms, and the natural microflora associated with freshly shelled hulls were monitored over a 90 day period. At the conclusion of the incubation period, the in-vitro digestibility of the hulls was determined. Although there was a substantial increase in protein content of all samples, there was drastic reduction in the in-vitro digestibility. Of the four components monitored, lignin content was found to be significantly negatively correlated with digestibility. These results suggest that pretreatment of peanut hulls with microorganisms alone will not increase the ruminant digestibility of the hulls.     

Modification of in-vitro digestibility and cell-wall composition of cocksfoot,ryegrass and timothy by imazethapyr

Recent studies have shown that the compound imazethapyr (5-ethyl-2-(4-isopropyl-4-methyl-5-oxo-2-imidazolin-2-yl)nicotinic acid) possesses growth regulatory activity and can be used to enhance nutritive value of grasses. However, little is known about possible effects of this material on fibre composition or potential fibre utilisation by ruminants. The objective of this research was to examine imazethapyr-treated cocksfoot (Dactylis glomerata L), ryegrass (Lolium perenne L × L multiflorum Lam), and timothy (Phleum pratense L) for possible treatment-induced changes in in-vitro digestibility and in concentrations of selected fibre constituents. Replicated field plots treated with imazethapyr at 0 (control) or 100 g ai ha^?1 during the vegetative (pre-elongation) stage of growth were harvested when controls were in the early stage of inflorescence emergence. Samples taken from treated plots 4 weeks post-treatment had higher in-vitro dry matter disappearance (IVDMD), lower neutral detergent fibre (NDF), lower acid detergent fibre (ADF), lower cellulose, lignin, and higher hemicellulose concentrations compared with controls. Imazethapyr treatment also reduced the concentration of p-coumaric acid in NDF, but had no effect on ferulic acid. The treatment effect on in-vitro NDF disappearance, however, was inconsistent among the grass species and was statistically non-significant (P = 0·10), implying that, under the conditions of this study, imazethapyr-related enhancements in IVDMD can be attributed primarily to a reduction in the amount of NDF and its associated constituents, as opposed to qualitative differences in NDF composition.     

Changes in chemical composition,grain malting,starch and tannin contents and protein digestibility during germination of sorghum cultivars

Malting loss and changes in chemical composition, starch and tannin contents and in vitro protein digestibility (IVPD) were determined during germination of low (0.32%) and high (1.44%) tannin sorghum cultivars. For both cultivars, crude protein, fibre, fat and ash contents were slightly decreased after soaking and germination of the seeds. Malting loss was slightly increased for both cultivars and for all germination periods. Starch degradation was high for both cultivars. Depending on the soaking time about 56–66% and 98–99% tannin were lost during 72 h germination in low and high tannin cultivars, respectively. IVPD was markedly decreased in the low tannin cultivar and markedly increased in the high tannin one with the germination time. Soaking, on the other hand, was found to have a minor effect on IVPD. It is suggested that tannins are responsible for retarding the protein digestibility and starch degradation, especially in the high tannin cultivar.     

Changes in the chemical composition of rabbit meat during growth

Relative growth rates of water, fat and protein by means of the allometric equation and changes in chemical composition of total meat, meat from hind leg and M. longissimus lumbaris from 1 to 20 weeks of age were studied in 320 rabbits of two strains (New Zealand White and California) and both sexes. All the chemical components showed changes in their allometric coefficients which determined variations in their relative percentages (P < 0·001) during the experimental period. Protein was characterized by a positive allometry although its rate of deposition decreased from 3-4 weeks of age. Water exhibited an important decrease in rate of deposition, passing from positive to negative allometry while, almost simultaneously, the rate of deposition of fat increased, passing from negative to positive allometry; nevertheless, the moment of change of these two components differed among the parts chemically analysed. All these changes were concentrated in a short interval of ages (3-7 weeks of age) that coincided with the one found for anatomic components of the carcass in a previous work (Deltoro & López, 1985). Significant differences (P < 0·001) for mean values were obtained among parts chemically analysed and, to a lesser degree, between lines and sexes. Meat from hind leg and M. longissimus lumbaris had a higher content of protein and a lower content of fat than the rest of the carcass meat. Relating the results to fat-free matter decreased differences but remained significant in most cases and indications of having attained chemical maturity at the end of the experimental period were obtained.     

Chemical composition and in vitro degradability of major chemical constituents in botanical fractions of red clover harvested at different stages of maturity

Red clover was harvested at five different stages of maturity during primary growth and separated into leaves, petioles, stems and flowers. The contents of extractives, crude protein, starch, non-starch polysaccharides, and non-starch polysaccharide constituents, and the in vitro degradability, were determined in the botanical fractions. Chemical analysis of the in vitro residues revealed that the degradability of crude protein was around 80% in all fractions at all harvest times whereas in most cases the degradability of non-starch polysaccharides and non-starch polysaccharide residues was highest in the leaf fractions, intermediate in the petiole fractions and lowest in the stem fractions, with only small changes occurring due to development and maturation during the investigated period. Glucose and xylose were the least degraded non-starch polysaccharide residues in all fractions.     

植物烹饪原料的化学成分与抗癌作用

本文介绍植物烹饪原料中的化学成分不仅具有营养价值，还有药用价值，许多原料的防癌，抗癌作用受到人们的重视，但是有些有效成分在烹调过程中会发生化学变化，降低丧失治疗作用，因此，要注意合理膳食，使之充分发挥作用。     

Chemical composition and in vitro digestibility of some Spanish browse plant species

Samples of leaves, flowers and fruits of four browse species were collected from uplands in the province of León (northwestern Spain) at different sampling times (from spring till autumn). The browse species were Erica australis (Spanish heath), Cistus laurifolius (laurel‐leaved rock rose), Quercus pyrenaica (hoary oak) and Rosa canina (wild dog rose). A large variability in chemical composition and in vitro digestibility and gas production kinetics was observed among species and among sampling times within each species. The ranking order of the browse plants according to their in vitro digestibility and gas production kinetics was R canina > Q pyrenaica > C laurifolius > E australis. In the leaves of R canina and Q pyrenaica, crude protein content, digestibility and parameters of gas production tended to decrease throughout the growing season (P < 0.05 in most cases), whereas cell wall contents followed the opposite trend. Seasonal variations were less pronounced in the other browse species. There were significant (P < 0.05) correlations between in vitro digestibility and chemical composition of the browse plants, positive with the crude protein content and negative with the fibre fractions. Copyright © 2004 Society of Chemical Industry     

Effect of ozone and ammonium hydroxide treatments on the composition and in-vitro digestibility of cotton straw

Cotton straw (CS) was treated with ozone, ammonium hydroxide and a combination of the two, and the effect of the treatments on the composition of cell wall (CW) fractions and on in vitro organic matter digestibility (OMD) was studied. The ammonium hydroxide treatment did not affect the lignin content, but a reduction of 50% in lignin and hemicellulose, and a corresponding increase in cell contents, were found in the ozone-treated materials. The pH of CS was reduced from 6.11 to 2.28 by ozone, probably due to the formation of organic acids derived from the oxidised lignin. Plateau-like ultraviolet (u.v.) spectra of the water extracts were obtained with all the treatments indicating that a variety of u.v. absorbing substances, including phenolic components, have been released. The extinction at 280 nm, suggested to indicate the concentration of phenolic components, was increased compared to the untreated CS by 37 and 98% with the ozone and the combined treatment, respectively; the ammonium hydroxide treatment had little effect. In vitro OMD was significantly increased by more than 100% by the ozone treatments, as a result of the partial conversion of cell walls into cell contents and the increased degradation of the CW. Ozone treatments increased the initial rate of in vitro OMD.     

Effect of plant oils and camelina expeller on milk fatty acid composition in lactating cows fed diets based on red clover silage

Five multiparous Finnish Ayrshire cows fed red clover silage-based diets were used in a 5 × 5 Latin square with 21-d experimental periods to evaluate the effects of various plant oils or camelina expeller on animal performance and milk fatty acid composition. Treatments consisted of 5 concentrate supplements containing no additional lipid (control), or 29 g/kg of lipid from rapeseed oil (RO), sunflower-seed oil (SFO), camelina-seed oil (CO), or camelina expeller (CE). Cows were offered red clover silage ad libitum and 12 kg/d of experimental concentrates. Treatments had no effect on silage or total dry matter intake, whole-tract digestibility coefficients, milk yield, or milk composition. Plant oils in the diet decreased short- and medium-chain saturated fatty acid (6:0-16:0) concentrations, including odd- and branched-chain fatty acids and enhanced milk fat 18:0 and 18-carbon unsaturated fatty acid content. Increases in the relative proportions of cis 18:1, trans 18:1, nonconjugated 18:2, conjugated linoleic acid (CLA), and polyunsaturated fatty acids in milk fat were dependent on the fatty acid composition of oils in the diet. Rapeseed oil in the diet was associated with the enrichment of trans 18:1 (Δ4, 6, 7, 8, and 9), cis-9 18:1, and trans-7,cis-9 CLA, SFO resulted in the highest concentrations of trans-5, trans-10, and trans-11 18:1, Δ9,11 CLA, Δ10,12 CLA, and 18:2n-6, whereas CO enhanced trans-13-16 18:1, Δ11,15 18:2, Δ12,15 18:2, cis-9,trans-13 18:2, Δ11,13 CLA, Δ12,14 CLA, Δ13,15 CLA, Δ9,11,15 18:3, and 18:3n-3. Relative to CO, CE resulted in lower 18:0 and cis-9 18:1 concentrations and higher proportions of trans-10 18:1, trans-11 18:1, cis-9,trans-11 CLA, cis-9,trans-13 18:2, and trans-11,cis-15 18:2. Comparison of milk fat composition responses to CO and CE suggest that the biohydrogenation of unsaturated 18-carbon fatty acids to 18:0 in the rumen was less complete for camelina lipid supplied as an expeller than as free oil. In conclusion, moderate amounts of plant oils in diets based on red clover silage had no adverse effects on silage dry matter intake, nutrient digestion, or milk production, but altered milk fat composition, with changes characterized as a decrease in saturated fatty acids, an increase in trans fatty acids, and enrichment of specific unsaturated fatty acids depending on the fatty acid composition of lipid supplements.     

Comparative study of phytic acid content,in-vitro protein digestibility and amino acid composition of different types of flat breads

Phytic acid content of eight different types of leavened and unleavened flat breads was determined. It was highest in unleavened and non-fermented whole wheat chapati and lowest in the leavened and fermented white wheat flat bread roghni nan. The effect of baking conditions, bread composition and phytic acid content on in-vitro digestibility of protein was measured using a pepsin multienzyme pH stat technique. The amino acids released were separated by ultrafiltration. The rate of protein digestibility of flat bread and amino acid released depended upon the type of flour used, baking conditions, phytic acid content and other antiproteolytic constituents of breads. Leavening and fermentation of breads resulted in an increase of protein digestibility and availability of amino acids. Addition of soya flour increases the protein digestibility of breads whereas millet flour decreases it.     

The effect of plant development and environment on formononetin concentration in red clover (Trifolium pratense L.)

Formononetin concentration in red clover herbage, determined by high performance liquid chromatography, was assessed in field, greenhouse and growth cabinet experiments. Formononetin content decreased in Hungaropoly swards from 5.6 mg g^?1 DM when harvested in early May to 3.5 mg g^?1 DM when harvested in mid-June. In the regrowth the sward with the shortest regrowth period had the highest concentration content (6.8 mg g^?1). In a pot experiment from vegetative through to the ‘dying inflorescence’ stage, formononetin concentration declined by 57% due to both a reduction in the concentration in stems more than in leaves and an increase in the proportion of stems in the dry matter. A temperature regime of 23/15°C (day/night) advanced flower appearance and adversely affected growth rate compared with 17/13°C. The lower temperature regime resulted in a higher formononetin content in expanded leaves (28% increase, mean of two harvests) and expanding leaves (17% increase). Incubation with β-glucosidase increased the amount of formononetin extracted in the stems. Phosphate fertiliser reduced the concentration of formononetin, 96 kg P ha^?1 reducing formononetin content by 32%, relative to red clover grown in soil with a low P content. The results are discussed in the context of the grazing management of red clover swards.     

The effect of cultivar and harvest date on the chemical composition and digestibility of fodder kale

The chemical composition and digestibility of seven marrow-stem, three thousand-head, and two curly kales were determined during the period from September to March. Differences between cultivars and between harvest dates were found for all of the characteristics assessed, but cultivar by harvest date interactions were not a serious problem. The largest differences in dry matter (DM) content were between the two curly kales (17.7%) and the other ten cultivars (14.0%), and between the mid-September harvest (11.3%) and the three later harvests (15.8%). Then, expressed as a percentage of the DM, the main results were as follows. The organic matter (OM) content was low in the mid-September (85.9 compared to 90.1) and contributed to a low digestible OM content (68.5 compared to 72.2). Amongst the marrow-stem kales were the extremes for digestible OM, namely 68.6 in an un-named marrow-stem stock and 73.5 in Maris Kestrel. The crude protein content fell from 22.1 in mid-September to 15.7 in mid-November, and then rose to 17.4 in January and March. The S-methyl cysteine sulphoxide (the haemolytic factor) content increased from 0.692 in mid-September to 1.21 in January and March, when the curly kales had 41% higher contents than the marrow-stem kales. The extreme thiocyanate ion (a goitrogen) contents occurred in mid-November (0.0152) and mid-January (0.0336), and ranged from 0.0157 in the marrow-stem cultivar Merlin to 0.0334 in the dwarf thousand-head cultivar Canson. Although not a yield trial, it was found that on average the DM yield of the curly kales was only 55% that of the marrow-stem and thousand-head kales.