Chemical characterisation and ruminal nutrient degradability of hulled and hull-less oats

The objectives of this study were to determine the chemical and ruminal nutrient degradability characteristics of two hulled (Calibre and AC Mustang) and one hull-less (AC Belmont) oat varieties. Ruminal nutrient degradability characteristics of the oat varieties were determined relative to barley using one ruminally fistulated cow. Neutral (NDF) and acid (ADF) detergent fibre levels were higher (P < 0·05) in hulled than hull-less oats. Hulled AC Mustang had higher (P < 0·05) NDF and ADF content than hulled Calibre. Starch content was higher (P < 0·05) in AC Belmont (590 g kg⁻¹) than Calibre (457 g kg⁻¹) and was higher in Calibre than AC Mustang (415 g kg⁻¹). Crude protein was higher (P < 0·05) in hull-less than hulled oat. Both hulled varieties had similar CP content (average 124 g kg⁻¹). Estimated digestible energy value was highest (P < 0·05) for AC Belmont (16·94 MJ kg⁻¹), intermediate for Calibre (14·18 MJ kg⁻¹) and lowest for AC Mustang (13·34 MJ kg⁻¹). Ruminal dry matter and NDF degradability were higher (P < 0·05) in hull-less than barley and was higher in barley than hulled oats. Ruminal starch degradability exceeded 900 g kg⁻¹ for all tested feeds and had the order AC Belmont = barley > Calibre = AC Mustang. It was concluded that oat varieties used in this study varied considerably in their chemical composition and ruminal degradability. When compared with barley, hulled oats had lower while hull-less oats had higher ruminal degradability. © 1998 SCI.     

Nutritional value of feed grade chickpeas for ruminants and pigs

The feeding value of feed grade chickpeas (Kabuli and Desi type) for ruminants and pigs was determined in two studies. Two ruminally fistulated cows were used in the first study to determine the effects of moist heat treatment (127 °C for 10 min) on the ruminal protein degradability of feed grade chickpeas. Heat treatment reduced (P < 0.05) soluble crude protein and increased (P < 0.05) the amount of crude protein associated with neutral detergent fibre for both types of chickpeas. Ruminal degradability of crude protein for Kabuli and Desi chickpeas was reduced by 39 and 33% (P < 0.05) respectively as a result of heating. In the second study, 64 crossbred pigs were each assigned to one of four dietary treatments in a factorial (4 treatments × 2 sexes) design experiment. The experimental barley/wheat‐based diets were supplemented with either soybean meal (control), Kabuli chickpeas (300 g kg⁻¹), Desi chickpeas (300 g kg⁻¹) or field peas (300 g kg⁻¹). Dry matter and gross energy digestibility coefficients, determined using the indicator method, were lower (P < 0.05) for the Desi‐ than for the Kabuli‐supplemented diet. However, no differences were observed in dry matter or gross energy digestibility between the Kabuli chickpea‐supplemented diet and the control or the field pea‐supplemented diet. Diets supplemented with chickpeas or field peas had a lower (P < 0.05) crude protein digestibility than the control diet. Pigs fed either of the chickpea‐supplemented diets during the growing phase gained less (P < 0.05) than pigs fed the control diet. However, during the finishing phase and over the entire experiment, dietary treatment had no effect on pig performance. There were no significant differences in carcass traits between pigs fed any of the four diets. It was concluded that moist heat treatment is an effective method to increase the rumen escape protein value of chickpeas and that the inclusion of feed grade Kabuli or Desi chickpeas in finishing diets up 300 g kg⁻¹ had no detrimental effects on pig performance. © 2000 Society of Chemical Industry     

Effects of varying the degree of synchrony of energy and nitrogen release in the rumen on the synthesis of microbial protein in lactating dairy cows consuming a diet of grass silage and a cereal-based concentrate

The object of the experiment was to test the hypothesis that altering the degree of synchrony in the ruminal release of available energy and nitrogen would affect microbial protein synthesis (MPS) when the diet contained a high proportion of readily fermentable carbohydrate. Four lactating dairy cows were given a basal diet of (kg DM day⁻¹) 8.0 grass silage, 4.2 barley and 1.8 groundnut meal containing 31.4 g N kg⁻¹ DM. The experiment was designed as a 4 × 4 Latin square with periods lasting 14 days. The treatments were (1) the basal diet given in two equal meals at 10:00 and 22:00 h (BASAL), supplemented with (2) 2.0 kg maltodextrin given as a continous intraruminal infusion (CONT), (3) 2.0 kg maltodextrin as two 6-h infusions starting at 10:00 and 22:00 h (SYNC) and (4) 2.0 kg maltodextrin given as two 6-h infusions starting at 16:00 and 04:00 h (ASYNC). All three infusion treatments reduced (P < 0.05) the concentration of ruminal ammonia relative to BASAL but only the CONT and SYNC treatments increased (P < 0.05) MPS over the level with BASAL; the value for ASYNC was the same as that for BASAL. Lactic acid was a minor product of the ruminal fermentation with all treatments. All three infusions reduced (P < 0.05) the plasma concentration of urea and the urinary output of nitrogen but there were no differences among the infusion treatments. It is concluded that with this diet, containing about 30% of DM as fermentable carbohydrate, altering the degree of synchrony in the rates of ruminal release of energy and nitrogen had a marked effect on MPS. © 1999 Society of Chemical Industry     

A comparative study on the determination of lactic acid in silage juice by colorimetric,high-performance liquid chromatography and enzymatic methods

The determination of lactic acid in the silage juice of artichokes with different additives (formid acid, molasses and NaCl) by the colorimetric method and its comparision with the high-performance liquid chromatography and enzymatic methods was investigated. The lactic acid content of the artichoke with molasses (62.1 g kg⁻¹) was higher than that of those with formic acid, or NaCl and without any additive (39.3, 33.0 and 43.2 g kg⁻¹, respectively). However, this effect was not significant (P > 0.05). There were significant differences on the method of measuring lactic acid of the artichoke silages (P < 0.001). The use of the enzymatic method resulted in a higher (75.6 g kg⁻¹) lactic acid content than when the colorimetric or HPLC methods were employed (with results of 42.0 and 28.9 g kg⁻¹, respectively). However, the levels of lactic acid in silage juices found using the colorimetric and HPLC methods were not different, and recovery percentages, by using the colorimetric method, were satisfactory (103.78%), when the detection limit at maximum level (30 µg ml⁻¹) was not exceeded. © 1999 Society of Chemical Industry     

Proteolytic activity in ruminal fluid from cattle fed two levels of barley grain: a comparison of three methods of determination

The effects of proportion of concentrate in the ruminant diet and the effects of freezing ruminal content prior to assay on proteolytic activity in ruminal inoculum were evaluated using three analytical techniques. A novel approach for determining proteolytic activity (PA) of ruminal fluid utilising ¹⁵N‐labelled casein was compared with two published procedures. In a crossover experiment, four heifers were fed two isonitrogenous diets containing (dry matter basis) 50% barley silage, 45% rolled barley grain and 4% soybean meal (medium‐grain diet, MG) or 8% barley silage, 89% rolled barley grain and 2% soybean meal (high‐grain diet, HG). Ruminal fluid was analysed either fresh or after having been frozen at ?40 °C for 45 days. Substrates utilised in measuring PA included ¹⁵N‐labelled casein (produced by infusing (¹⁵NH)₂SO₄ into the rumen of a lactating dairy cow), ¹⁴C‐labelled casein and azocasein. Incubations were conducted in 0.2 M phosphate buffer (pH 6.8) for 20 min at 39 °C. In the ¹⁵N‐casein incubations, PA was estimated as (i) N soluble in 5% trichloroacetic acid (TCASN), (ii) N soluble in 5% TCA corrected for microbial N uptake (TCAMICR) and (iii) N depleted from the soluble protein N pool (SPR). In the ¹⁴C‐casein incubations, PA was measured as TCA‐soluble radioactivity; in the azocasein method it was measured as dye released during incubation. Across treatments the highest (P < 0.001) proteolytic activity was measured by the SPR method, followed by TCAMICR, TCASN and ¹⁴C‐casein. The lowest activity was recorded using the azocasein method. Within the ¹⁵N‐ and ¹⁴C‐casein methods, PA in previously frozen ruminal fluid was higher (P < 0.05) with the HG diet than with the MG diet, and higher (P < 0.05) in previously frozen fluid than in inoculum processed fresh. This study demonstrates that increasing the proportion of grain in the diets of cattle and freezing the ruminal inoculum both increase proteolytic activity measured in ruminal fluid. The proposed ¹⁵N‐casein method yielded higher proteolytic activity values than the ¹⁴C‐casein method. Copyright © 2002 Society of Chemical Industry. Contributions of A N Hristov, T A McAllister and Z Xu. © Minister of Public Works and Government Services, Canada 2002.     

Effects of intraruminal infusions of propionate and butyrate with two different protein supplements on milk production and blood metabolites in dairy cows receiving grass silage-based diet

Four cows were used in a balanced 4×4 Latin square with 2 week experimental periods to investigate the effects of intraruminal infusions of volatile fatty acids and protein source on milk production and blood metabolites. The four treatments in a 2×2 factorial arrangement were isoenergetic intraruminal infusions of propionate (500 g day⁻¹) or butyrate (417 g day⁻¹) each given with isonitrogenous protein supplementation of fish meal (FM) or barley protein (BP). The cows were fed restrictively with 9 kg dry matter day⁻¹ of formic acid treated grass silage and 8 kg day⁻¹ of concentrate. Propionate infusion increased milk yield (24·9 vs 23·4 kg day⁻¹; P<0·05), milk protein yield (832 vs 778 g day⁻¹; P=0·05) and milk lactose content (44·7 vs 43·5 g kg⁻¹; P<0·05) and yield (1113 vs 1023 g day⁻¹; P<0·01), whereas butyrate infusion was associated with a higher milk fat content (44·7 vs 39·4 g kg⁻¹; P<0·01) and yield (1033 vs 974 g day⁻¹; P<0·01). FM tended (P<0·10) to increase milk yield, but had no significant effects on milk composition or milk component yields compared with BP. Butyrate infusion increased blood ketones, plasma non-esterified fatty acids and glycine relative to propionate infusion. The concentrations of ammonia N in rumen fluid and urea in plasma and milk were similar for both protein supplements. The profile of amino acids in plasma was similar for both protein supplements except for the higher concentrations of phenylalanine, proline and tyrosine with BP. The results show that protein utilisation can be improved by increasing the supply of propionate from rumen fermentation in cows given a grass silage-based diet. © 1998 SCI.     

Substitution of wheat starch with non-wheat starches and cross-linked waxy barley starch affects sensory properties and staling of Arabic bread

Substitution of starch from barley, corn, oat, potato, rice or sorghum for prime wheat starch in the formulation of Arabic bread resulted in breads with significantly (P < 0.05) different textural attributes from regular wheat bread except for barley starch. Substitution of waxy barley starch (957 g kg⁻¹ amylopectin) for wheat starch (279 g kg⁻¹ amylopectin) resulted in bread that was not significantly different from regular wheat bread when assessed in the fresh state. However, upon aging, the waxy barley starch-containing bread staled at a significantly (P < 0.05) faster rate than regular wheat bread. Breads made with waxy barley starch cross-linked with 50, 200 or 500 ppm phosphorus oxychloride showed higher enthalpy of melting (ΔH) upon aging and staled faster than the bread formulated with waxy barley starch. These findings suggest that amylopectin retrogradation is one of the determinants of Arabic bread staling and that cross-linking promotes recrystallisation of amylopectin, possibly by keeping the polymer chains in close proximity. The rate of staling in breads formulated with cross-linked waxy barley starch decreased with increasing levels of cross-linking, possibly owing to restrictions in the degree of starch swelling. © 1999 Society of Chemical Industry     

Effects of varying degrees of synchrony of energy and nitrogen release in the rumen on the synthesis of microbial protein in cattle consuming grass silage

The effect of the degree of synchrony in the ruminal release of energy and nitrogen on microbial protein synthesis (MPS) was examined in cattle consuming grass silage (7.9 kg DM day⁻¹) and a supplement of 1 kg day⁻¹ of sucrose given as an intraruminal infusion. The sucrose was infused in three different patterns to induce varying degrees of synchrony of energy and nitrogen release. Four non‐lactating cows received four experimental treatments in a 4 × 4 Latin square design with periods lasting 14 days. The treatments were (1) the basal diet of silage alone given in two equal meals each day at 10.00 and 22.00 h (BASAL), supplemented with (2) 1.0 kg sucrose given as a continuous infusion (CONT), (3) 1.0 kg sucrose given as two 6‐h infusions starting at 10.00 and 22.00 h (SYNC) and (4) 1.0 kg sucrose given as two 6‐h infusions starting at 16.00 and 04.00 h (ASYNC). The different patterns of infusing the sucrose altered (P < 0.05) the pattern of variation in ruminal concentrations of ammonia and the molar proportions of acetic and butyric acids at times during the interval between meals but none of the sucrose treatments resulted in any increase in the ruminal concentration of lactic acid. All sucrose treatments increased (P < 0.05) MPS relative to BASAL by, on average, about 23 g day⁻¹. The increase in MPS for the SYNC and ASYNC treatments were identical at 20 g kg⁻¹ sucrose. It is concluded that synchronising the rates of ruminal release of energy and nitrogen had no effect on MPS. © 1999 Society of Chemical Industry     

Effects of proanthocyanidins,dehulling and removal of pericarp on digestion of barley grain by ruminal micro‐organisms

The effects of proanthocyanidins (PA), dehulling, and removal of the pericarp on the rate and extent of barley digestion by ruminal micro‐organisms were studied using a control barley (cv Harrington) and three PA‐free barley lines (Caminant, Ca504316 and Ca802711). Each barley was studied in five preparations: whole grain (W); dehulled kernels (DH); kernels with pericarp removed (DP); dry‐rolled grain (DR), and the pericarp‐testa fraction (PT) produced during preparation of DP. Vanillin‐HCl staining and chemical analysis confirmed that PA were present only in the Harrington barley, and localised in the pericarp‐testa layer. Whole kernels, DH and DP were incubated with diluted ruminal fluid in vitro, and all five preparations were incubated in situ (nylon bag technique). Harrington DR and all four PT fractions were also incubated in vitro in the presence (0.074% w/v) and absence of polyethylene glycol (PEG), which specifically binds PA. The four barleys did not differ in in vitro dry matter disappearance (DMD) or gas production from W, DH or DP preparations, nor in in situ DMD rates from W, DH or DP (P > 0.05). In vitro DMD and gas production among PT fractions from the four barleys were also similar (P > 0.05), as were in vitro DMD from PEG‐present and PEG‐absent DR Harrington. With Harrington PT, in vitro ammonia concentrations were higher (P < 0.05) with PEG than without. For each barley line, in vitro DMD rates were highest (P < 0.01) with DP, followed by DH, and then by W (P < 0.01). In in situ incubations also, DMD rates and effective degradabilities of DR samples exceeded (P < 0.05) those of DH samples. It was concluded that the presence of proanthocyanidins did not affect ruminal digestion of barley grain, and that abrasive milling to breach the hull and pericarp may be a promising method by which to regulate the rate of barley digestion in the rumen. © Minister of Public Works and Government Services Canada 1999     

Chemical composition and ruminal degradability of lucerne (Medicago sativa) products

A study was conducted to determine the chemical composition and in situ nutrient ruminal degradability of three lucerne products. These were dehydrated pellets, sun‐cured pellets and cubes. Results of the chemical analysis showed that sun‐cured pellets had the highest (P < 0.05) neutral and acid detergent fibre as well as total carbohydrate levels, followed by cubes and dehydrated pellets respectively. Crude protein (CP) content was highest (P < 0.05) for dehydrated pellets (204.3 g kg^?1), intermediate for sun‐cured pellets (160.0 g kg^?1) and lowest for cubes (153.2 g kg^?1). Intermediately degradable CP (buffer‐insoluble CP minus neutral detergent‐insoluble CP) was the main protein fraction in the three products and was higher (P < 0.05) in cubes than in dehydrated and sun‐cured pellets. Estimated net energy of lactation was highest (P < 0.05) for dehydrated pellets (5.9 MJ kg^?1), intermediate for cubes (5.23 MJ kg^?1) and lowest (P < 0.05) for sun‐cured pellets (5.15 MJ kg^?1). Results of the in situ experiment indicated that dehydrated pellets had higher (P < 0.05) ruminal protein degradability than sun‐cured pellets and cubes. The estimated ruminal escape protein values for dehydrated pellets, sun‐cured pellets and cubes were 361, 420 and 498 g kg^?1 CP respectively. It was concluded that differences in chemical composition and ruminal degradability among the three lucerne products were mainly due to differences in stage of maturity. It was also concluded that the dehydration process failed to increase the ruminal escape protein value of dehydrated pellets relative to sun‐cured pellets and cubes. © 2001 Society of Chemical Industry     

The nutritive value for ruminants of thin stillage and distillers' grains derived from wheat,rye, triticale and barley

A study was conducted to determine nutrient degradabilities of thin stillages and distillers' grains derived from wheat‐, rye‐, triticale‐ and barley‐based ethanol production. In vitro protein degradabilities of wheat, rye, triticale and barley thin stillages were determined using a protease enzyme assay. One ruminally fistulated cow was used to determine ruminal nutrient degradabilities for wheat, rye, triticale and barley distillers' grains. Results of the in vitro study showed that the soluble protein fraction was highest for rye thin stillage and lowest for barley thin stillage. The degradation rate of the slowly degradable protein fraction was higher for wheat and triticale thin stillage than rye thin stillage and was higher for rye than barley thin stillage. Effective degradability of crude protein followed the order rye (659 g kg⁻¹) > triticale (632 g kg⁻¹) > wheat (608 g kg⁻¹) > barley (482 g kg⁻¹) thin stillage. Ruminal degradability of dry matter was highest for rye and lowest for barley distillers' grains. Ruminal degradability of dry matter was also higher for wheat than triticale distillers' grains. Crude protein from barley distillers' grains had a lower ruminal degradability relative to crude protein from wheat and rye distillers' grains. Ruminal degradability of neutral detergent fibre was highest for rye distillers' grains (470 g kg⁻¹), intermediate for wheat and triticale distillers' grains (average 445 g kg⁻¹) and lowest for barley distillers' grains (342 g kg⁻¹). It was concluded that thin stillage and distillers' grains derived from barley had a lower nutritive value for ruminants compared with those derived from wheat, rye and triticale. © 2000 Society of Chemical Industry     

In vitro biohydrogenation and total tract digestibility of oleamide by sheep

Disappearance of cis-18:1(n-9) from ruminal in vitro cultures supplemented with either oleic acid or oleamide was measured over 48 h to determine if the amide resisted biohydrogenation. Oleamide added to the substrate maintained higher concentrations of cis-18: 1(n-9) in the microbial cultures at 24 and 48 h of incubation compared to substrates with added oleic acid. Disappearance rates of cis-18: 1(n-9) from the cultures, which were calculated as a measure of biohydrogenation, were 0·064 and 0·025 h⁻¹ for the oleic acid and oleamide supplements, respectively. Four sheep were fed four diets (control, 42 g kg⁻¹ oleic acid, 23 g kg⁻¹ oleamide, and 45 g kg⁻¹ oleamide) in a 4×4 Latin square to determine how the amide affected fatty acid digestibility. Total tract digestibilities of protein and fibre were not affected (P>0·05) by either oleic acid or oleamide compared to the control diet. Fatty acid and energy digestibilities were not changed (P>0·05) by oleic acid, but were increased (P<0·05) when oleamide was added to the sheep diets at 45 g kg⁻¹. These results show that oleamide resists ruminal biohydrogenation without impairing fatty acid digestibility. © 1998 SCI.     

Nutrient contents,rumen protein degradability and antinutritional factors in some colour- and white-flowering cultivars of Vicia faba beans

Six colour-flowering (Scirocco, Alfred, Carola, Condor, Tina and Herz Freya) and six white-flowering (Caspar, Albatros, Gloria, Tyrol, Vasco and Cresta) cultivars of Vicia faba were studied. The crude protein contents of colour- and white-flowering cultivars were 267±13·6 and 283±18·8 g kg⁻¹, respectively, which did not differ significantly at P<0·05. The levels of lipids, crude fibre, starch and ash varied from 14 to 22 g kg⁻¹, 88 to 143 g kg⁻¹, 407 to 485 g kg⁻¹ and 32 to 42 g kg⁻¹, respectively. The calculated organic matter digestibility (OMD) and metabolisable energy (ME) of the white-flowering cultivars were significantly higher (P<0·001) than those of the colour-flowering cultivars (OMD: 889·1±26·6 g kg⁻¹ vs 797·5±17·1 g kg⁻¹; ME: 13·97±0·49 vs 12·30±0·34 MJ kg⁻¹). In all cultivars, sulphur amino acids were lower than adequate concentration when compared with recommended amino acid pattern of FAO/WHO/UNO reference protein for a 2–5-year-old child. The in vitro rumen nitrogen degradability of colour-flowering cultivars was significantly lower (P<0·01) compared to that of white-flowering cultivars (71·4±9·3% vs 88·0±11·1%). Amongst colour-flowering varieties, the contents of total phenols (TP), tannins (T) and condensed tannins (CT) were highest in Alfred (28·3, 21·0 and 35·4 g kg⁻¹, respectively). The contents of TP and T were similar (about 15 and 10 g kg⁻¹, respectively) in Carola, Tina and Herz Freya, and the CT were in the order: Condor>Herz Freya>Carola. The CT were not detected in white-flowering varieties, T were virtually absent and TP were extremely low (4·0–4·9 g kg⁻¹). The activities of other antinutritional factors (white- and colour-flowering cultivars, respectively: trypsin inhibitor activity 3·05±0·34 and 1·85±0·09 mg trypsin inhibited g⁻¹; lectin 27·2±9·4 and 27·1±5·1 mg ml⁻¹ assay medium producing haemagglutination; phytate 15·0±2·7 and 16·6±2·3 g kg⁻¹) were very low. A strong negative correlation (r=-0·92, P<0·001) between tannins and in vitro rumen protein degradability was observed which suggested that tannins have adverse effect on protein degradability. Similarly negative correlations between tannin levels and metabolisable energy (r=-0·89; P<0·001) and organic matter digestibility (r=-0·89; P<0·001) were observed. The correlation coefficient between trypsin inhibitor activity and tannins was negative and highly significant (r=-0·88, P<0·001), whereas between tannins and saponins it was significantly positive (r=0·96, P<0·001). ©1997 SCI     

Phytosterol content in seven oat cultivars grown at three locations in Sweden

The total and individual sterol content in 21 oat samples (seven cultivars grown at three different locations in Sweden) were analysed by gas chromatography after acid hydrolysis. The total sterol content in these oat cultivars varied between 350–491 µg g⁻¹ of dry weight of kernel. The most abundant phytosterol was β‐sitosterol (237–321 µg g⁻¹) followed by campesterol (32–46 µg g⁻¹), Δ⁵‐avenasterol (15–47 µg g⁻¹) and stigmasterol (11–21 µg g⁻¹). There was a statistically significant difference in total sterol content between cultivars (p < 0.05) but no effect was found for cultivation location. Furthermore when contents of Δ⁵‐avenasterol in hexane‐extracted oat oil and acid‐hydrolysed oat samples were compared, it was noticed that the content of Δ⁵‐avenasterol was lowered due to acid hydrolysis. © 1999 Society of Chemical Industry     

Effects of variety on chemical composition,in situ nutrient disappearance and in vitro gas production of spineless cacti

This study determined the chemical composition, in situ ruminal nutrient disappearance and in vitro gas production kinetics of three cactus varieties grown in northeastern Brazil. The varieties were Gigante, IPA‐20 and Miúda. Results of the chemical analysis showed no significant differences in ash, ether extract, crude protein (CP) and neutral detergent fibre (NDF) between the cactus varieties. However, acid detergent fibre was highest (P < 0.05) for IPA‐20, intermediate (P < 0.05) for Gigante, and lowest (P < 0.05) for Miúda. Fractionation of carbohydrate and true protein based on rates of ruminal degradation indicated that the main carbohydrate component was the rapidly degradable fraction, whereas the main true protein component was the intermediately degradable fraction. No differences in carbohydrate or protein fractions were observed between the cactus varieties. Results of the in situ experiment showed no differences in ruminal dry matter (DM, average 803 g kg^?1 of DM), CP (900 g kg^?1 of CP) and NDF (611 g kg^?1 of NDF) disappearance between the three cactus varieties after 48 h of ruminal incubation. Potential gas production at the end of 48 h of incubation was higher (P < 0.05) for Gigante than for the Miúda or IPA‐20 variety. However, rate of gas production and lag time in gas production were similar for the three cactus varieties at 6.8% h^?1 and 0.6 h respectively. Our results showed little or no differences in chemical composition or ruminal nutrient degradabilities between the three cactus varieties. Copyright © 2003 Society of Chemical Industry     

In vitro effects of phlorotannins from Ascophyllum nodosum (brown seaweed) on rumen bacterial populations and fermentation

BACKGROUND: Use of brown algae (seaweed) in ruminant diets is increasing, but the effects of its phlorotannins (PT) on rumen microbial ecology have not been determined. Mixed forage (50:25:25 ground barley silage–alfalfa hay–grass hay) was used as substrate in a batch culture ruminal incubation that included PT extracted from Ascophyllum nodosum, with and without polyethylene glycol. Principal ruminal bacteria were quantified using real‐time polymerase chain reaction. RESULTS: At 500 µg mL^?1, PT reduced growth of Fibrobacter succinogenes by 78%, 83% and 65% at 6, 12 and 24 h (P < 0.001), Ruminococcus albus at 24 h only (P < 0.01) and did not affect R. flavefaciens. Non‐cellulolytic bacteria Selenomonas ruminantium, Ruminobacter amylophilus and Prevotella bryantii were increased (P < 0.001) by PT at 12 and 24 h. Effects of PT on fermentation products (gas production, volatile fatty acid profiles and ammonia accumulation) were consistent with alterations in rumen microbial populations. CONCLUSION: The effects of PT on ruminal bacteria were species‐dependent, which suggests that diet may mediate PT effects on animal performance. The variation in sensitivity of ruminal bacteria to PT reflects previously reported effects of condensed tannins from terrestrial plants on microbial populations. Copyright © 2009 Crown in the right of Canada. Published by John Wiley & Sons, Ltd     

Effect of the duration of feeding of a protein‐free diet on endogenous ileal nitrogen and amino acid loss in the growing pig

The aim of the study was to determine whether endogenous nitrogen and amino acid excretions at the terminal ileum change over time in the growing pig fed a protein‐free diet for 8 days. Seven entire male pigs with an overall mean live weight of 81.6 kg (SEM 3.3 kg) and surgically implanted post‐valve T caecum cannulas were fed a semi‐synthetic casein‐based diet for 8 days. Food was withheld from the pigs for 24 h, after which they were fed a protein‐free diet for a further 8 days at a rate of 10% of metabolic body weight per day. Chromic oxide was included in the protein‐free diet as an indigestible marker. Ileal digesta were collected continuously from 13:00 to 18:00 h on each day of the experimental period. Endogenous ileal nitrogen flows were determined for each pig each day the protein‐free diet was given, and endogenous ileal amino acid flows for the first and eighth days. There were no significant (P > 0.05) effects of the duration of feeding of the protein‐free diet on endogenous ileal total nitrogen or amino acid flows, except for the amino acids glycine and cysteine, the flows of which significantly decreased over the 8 day period (P < 0.01 and P < 0.05 for glycine and cysteine respectively), from (mean ± SEM) 1639 ± 217 to 892 ± 212 µg g⁻¹ dry matter intake (DMI) for glycine and from 173 ± 13 to 127 ± 19 µg g⁻¹ DMI for cysteine. The relative contributions (moles of each amino acid as a proportion of total moles of amino acids) of threonine, glycine and cysteine decreased significantly (P < 0.05) and that of proline increased significantly (P < 0.05) during the 8 days that the protein‐free diet was fed to the pigs. © 2000 Society of Chemical Industry     

Enhancing bioavailability and hepatoprotective activity of andrographolide from Andrographis paniculata,a well‐known medicinal food,through its herbosome

BACKGROUND: Andrographis paniculata is a health food used extensively in Southeast Asia, India and China and contains the pharmacologically important phytochemical andrographolide. Although andrographolide has antihepatotoxic activity, its bioavailability from A. paniculata is restricted by its rapid clearance and high plasma protein binding. The aim of this study was to formulate a herbosome of andrographolide with a naturally occurring phospholipid in order to enhance the bioavailability and hepatoprotective activity of andrographolide in rats. RESULTS: Andrographolide herbosome equivalent to 25 and 50 mg kg⁻¹ andrographolide significantly protected the liver of rats, restoring hepatic enzyme activities with respect to carbon tetrachloride‐treated animals (P < 0.05 and P < 0.01 respectively). The rat plasma concentration of andrographolide obtained from the complex equivalent to 25 mg kg⁻¹ andrographolide (C_max = 9.64 µg mL⁻¹) was higher than that obtained from 25 mg kg⁻¹ andrographolide (C_max = 6.79 µg mL⁻¹), and the complex maintained its effective plasma concentration for a longer period of time. CONCLUSION: The results proved that the andrographolide complex produced by this method has better bioavailability and hence improved hepatoprotective activity compared with andrographolide at the same dose. Andrographolide complexation is therefore helpful in solving the problem of rapid clearance and low elimination half‐life associated with andrographolide from A. paniculata. Copyright © 2009 Society of Chemical Industry     

Antioxidant and antimicrobial activities of Polygonum cognatum Meissn extracts

The antioxidant activities, reducing powers, 2,2‐diphenyl‐l‐picrylhydrazyl (DPPH) radical‐scavenging activities, total phenolic compound contents and antimicrobial activities of ether, ethanol and hot water extracts of Polygonum cognatum Meissn were studied in vitro. The highest antioxidant activity was found in the water extract. However, there were no statistically significant differences among 15 µg ml^?1 extract‐containing samples in linoleic acid emulsion (0.02 M , pH 7.0) during 120 h of incubation (P > 0.05). The reducing power of the water extract was the highest, but its reducing power was markedly lower than that of ascorbic acid. The highest DPPH radical‐scavenging activity was found in the water extract, with 50% DPPH radical scavenging at a concentration of 100 µg ml^?1 dried water extract, while at the same concentration of dried ethanol extract the value was 12%. Surprisingly, no DPPH radical‐scavenging activity was observed in the ether extract. The concentrations of phenolic compounds found were 0.48, 0.50 and 0.01 µg ml^?1 gallic acid equivalent in 10 µg ml^?1 water, ethanol and ether extracts respectively. The ether and ethanol extracts showed antimicrobial activity against Staphylococcus aureus and Bacillus subtilis. The water extract did not show antimicrobial activity against the studied micro‐organisms. © 2002 Society of Chemical Industry     

Characterisation of peptides in silages made from perennial ryegrass with different silage additives

The effects of applying either formic acid (5.4 g kg⁻¹), a mixture of formic acid (2.7 g kg⁻¹) and formaldehyde (1.5 g kg⁻¹, 81 g kg⁻¹ herbage crude protein) or two concentrations of a cysteine peptidase inhibitor, cystamine (5 or 50 g kg⁻¹), to perennial ryegrass (Lolium perenne) on the nitrogen (N) distribution of the resulting silages were investigated, with emphasis on changes in concentration, composition and molecular weight of silage peptides. Herbage (156 g dry matter kg⁻¹ and 141 g water‐soluble carbohydrate kg⁻¹ dry matter) was ensiled in triplicate in laboratory silos for 100 days. Formic acid and the formic acid/formaldehyde mixture reduced soluble non‐protein N and ammonia N concentrations (P < 0.01); in addition, formic acid increased peptide N concentrations (P < 0.05). Cystamine at 50 g kg⁻¹ reduced ammonia N concentrations (P < 0.01) and increased peptide N concentrations (P < 0.05), but when applied at 5 g kg⁻¹ had little effect. Gel filtration of silage extracts on Sephadex G‐25 suggested that a small proportion (0.06–0.11 g kg⁻¹ peptide N) of silage peptides had a chain length of 7–9 amino acids, but remaining peptides were smaller with chain lengths of 2–6 amino acid residues. Amino acid analysis of silage peptides indicated that additive treatment had little effect on peptide amino acid composition but that peptides with a chain length of 7–9 amino acids contained lower proportions of isoleucine and arginine. © 2000 Society of Chemical Industry