Fibre Bags Research Articles

The use of a novel in vitro technique for the assessment of the ruminal degradation of soya bean meal.

The metabolisabie protein system (AFRC, 1992) requires the measurement of the dynamics of the degradation of protein in the rumen. However the recommended method, using fistulated animals, is slow, expensive and may be considered unacceptable by many in terms of animal welfare. The objective of this work was to develop an in vitro technique for the routine assessment of feed protein degradability.A 101 vessel fitted with an automatic stirrer was filled with modified van Soest media and rumen liquor (pooled from two sheep) and maintained under anaerobic conditions at 39.5°C. Small artificial fibre bags (4.5x3cm, pore size 54 micro-m ±4) were filled with 0.4g of soya bean meal and incubated in the vessel for 3,6,10 and 24 hours using 3 replicates at each time. Bags were washed in running cold water for 30 mins immediately after removal. Four replicates of 3g samples in large Dacron bags (10x7cm, pore size 55 micro-m ±22) were also incubated in sacco in fistulated yearling wethers using a 4x4 Latin square design to assess the base line degradability. In sacco bags were rinsed and frozen after removal and washed in a domestic washing machine at the end of the experiment.

Use of a combined synthetic fibre bag method to estimate the true total tract digestion of organic matter and nitrogen of hay and grass silage in cows

A 4 x 4 Latin square experiment was designed to determine and compare the total tract digestion of organic matter (OM) and nitrogen of hay and grass silage by combining the ruminal and intestinal digestion estimates obtained by the rumen bag and mobile bag methods. The diets were composed of forage alone or 30% forage and 70% barley. The rumen degradation (RD) was calculated using the degradation constants a, b, and c obtained to the forages, according to the equation RD = a+bc/(c+k). Intestinal digestion of escape feeds was estimated using the feed residues that resisted rumen degradation during 16 hours. For comparative purposes, the total tract digestion was also calculated based on the actual rumen degradation of forages during 16 hours rumen incubation. The effect of dietary interaction on the digestion of forages was assessed. Rumen degradation values obtained by 16 hours incubation did not provide sufficient basis to estimate reliably the total tract digestion by the combined bag method. Using calculated RD total tract digestion of OM of hay and grass silage were rather close to conventional in vivo digestion coefficient of respective feeds similar in chemical composition, when barley was not included in the diet. With hay, but not with grass silage, barley always markedly reduced the rumen degradation and total digestion of OM. Barley supplementation always increased the proportion of feed digested in the intestine. Nitrogen digestion was always higher with grass silage than with hay, and the combined bag method produced N digestion values 17.6-22.0%-units higher than those in the feed table. Barley supplementation did not affect the N digestion of the forages.(ABSTRACT TRUNCATED AT 250 WORDS)

In vitro and in vivo studies of factors affecting digestion of feeds in synthetic fiber bags.

Dry matter disappearance (DMD) and cellulose disappearance (CD) from alfalfa hay were measured simultaneously in synthetic fiber bags incubated in vitro. In general, DMD, CD, and pH were reduced (P less than .05) inside the bags compared with values in the fermentation flasks. Bags became fully expanded with gas soon after the fermentation started, which seemed to inhibit fluid movement into and out of the bag. By creating a vacuum in the flask, fluid exchange was enhanced, and DMD, CD, and pH increased (P less than .01) inside the bags. Sample size, type of fabric, and fabric pore size affected pH, DMD, and CD. Inoculum source (forage or concentrate diet) did not affect DMD in either bags or flasks. In contrast, DMD in bags incubated in vivo was affected (P less than .01) by animal diet. When bags were incubated in vivo inside a rigid plastic container, both pH and DMD were reduced (P less than .01) compared with bags suspended freely in the rumen. Direct physical action of ruminal contents on the bags apparently enhanced exchange of fluid. Bacterial concentrations in bags suspended freely in the rumen were greater than those in bags incubated inside containers. Synthetic fiber bags may be useful in comparing digestibility between diets; however, caution is needed in evaluating such data in absolute terms.

Evaluation of Different Chromium-Mordanted Wheat Straws for Passage Rate Studies

Samples of untreated and ammonia-treated wheat straw were mordanted with sodium dichromate after being chopped, ground, or ground and washed in neutral detergent solution. The NDF content of the mordanted samples increased to 97 to 100% DM in those ground or ground and neutral detergent-washed, whereas the increase was lower (92% DM) in those chopped. Chromium content after mordanting was 4.0% DM in the samples washed in neutral detergent solution and 2.4 to 2.6% DM in those simply chopped or ground. There were no major differences due to ammonia treatment. Particle size distribution of ground samples showed significant differences in proportions of particles larger than 1mm with control samples less than ground and mordanted samples less than ground, neutral detergent-washed, and mordanted samples. There also were variable and significant effects of these treatments on functional specific gravity. Rumen DM disappearance after 48-h incubation in fiber bags was reduced greatly by mordanting but was negligible only with the previous neutral detergent treatment.The estimated rumen passage rates of mordanted samples of untreated straw differed significantly among treatments with chopped samples less than ground samples, which were less than ground and neutral detergent-washed samples, reflecting their differences in particle size and functional specific gravity. It was concluded that the mordanting procedure can affect greatly the physicochemical properties of feedstuffs, thus altering their passage rates.

Electrowinning study of galena concentrate with a carbon fibre bag electrode

By using a carbon fibre bag containing lead concentrate as an anode in a synthetic acetate-perchlorate electrolyte, the extent of anodic dissolution of lead has been found to be better than 80%, and the lead deposition on the cathode has been found to be almost equivalent to the lead dissolved from the anode. Complexing agents such as EDTA help in obtaining flaky deposits. This process seems to solve many of the problems which arise when cast or compressed anodes are used.

Prediction of voluntary intake of conserved forages by cattle and sheep from degradability characteristics determined using synthetic fibre bags in sheep

Hovell et al. (1986) proposed that degradation characteristics of forages, as measured in nylon bags, may have useful application in predicting voluntary intakes. They reported intakes of four hays by sheep were more closely related to the potential degradability of forage dry matter (DM) than to in vivo The present work was undertaken to examine these relationships with forages and with both young growing cattle and sheep.Seven forages were prepared with the objective of providing material wide range of voluntary intake. The forages were:(i)WS, wheat straw(ii)AWS, round-baled WS wrapped in 4 layers of overlapping plastic sheet (Silawrap; Volac Ltd), injected with 32% aqueous ammonia at the rate of 40kg/1000kg DM(iii)H1, first cut ryegrass hay(iv)H2, second cut ryegrass hay from the same field as (iii)(v)S2, 50% DM silage, baled and wrapped with Silawrap, prepared from the same crop as H2(vi)ES2, the same crop as S2 sprayed with a mixed enzyme preparation (Deezyme, Finnish Sugar Company Ltd.) at 0.81/tonne immediately before baling and wrapping with Silawrap(vii)AS2, S2 treated with aqueous ammonia in the wrapped bale as for AWS. All forages were fed in the long form except WS which was coarsely chopped through a straw chopper without any retaining screen into approximately 7cm lengths.

The digestion by cattle of silage and barley diets containing increasing quantities of fishmeal

SummaryA 4 × 4 latin-square design experiment was carried out to determine the effects of increasing nitrogen (N) intake by feeding diets containing increasing amounts of fishmeal upon the digestion of organic matter (OM) and N by cattle equipped with rumen and duodenal cannulae. A basal diet (B) containing 600 g silage and 400 g ground barley/kg diet and three diets (BF1, BF2 and BF3) in which increasing amounts of the silage and barley basal diet were proportionately replaced by fishmeal were fed. The mean daily intakes of OM and N when each diet was fed were 4·29, 4·28, 4·22 and 4·20 kg OM and 90, 108, 125 and 143 g N for diets B, BF1, BF2 and BF3 respectively.Neither the amounts of OM entering the small intestine nor those voided in the faeces were altered by the diets fed. Thus mean apparent OM digestibility for all the diets fed was 0·74 ± 0·007 and the proportion of digestible OM intake apparently digested in the rumen was 0·83±0·011.Mean daily concentrations of ammonia N in the rumen were significantly(P <0·01) increased from 85 mg N/l (diet B) to 129 mg N/1 (diet BF3) as fishmeal intake increased.The quantities of non-ammonia N (P<0·05) and of amino acid N (P<0·001) entering the small intestine were significantly increased as more fishmeal was added to the diets fed. As fishmeal intake increased apparent N digestibility was significantly (P<0·001) increased.Neither the quantities of microbial N entering the small intestine daily nor the apparent efficiency of microbial N synthesis within the rumen were increased by the diets fed. The quantities of feed N entering the small intestine daily were significantly (P<0·01) increased as fishmeal intake increased; thus apparent feed N degradability in the rumen was significantly (P<0·05) decreased from 0·84 (diet B) to 0·73 (diet BF3) as fishmeal intake increased. Similarly, the rates of disappearance of N from each of the four barley or barley and fishmeal concentrates when incubated in the rumens of the cattle in porous synthetic fibre bags were decreased as the proportion of fishmeal in the concentrates increased. Thus, the rumen N degradability of the diets fed, when calculated from the rates of disappearance of N from porous synthetic fibre bags placed in the rumen, decreased as fishmeal intake increased.As fishmeal intake increased the amino acid composition of duodenal digesta (expressed as g/kg determined amino acids) changed such that the content of arginine increased (P<0·01) and the content of isoleucine decreased (P<0·01). The concentrations of arginine (P<0·01), leucine and lysine (P<0·05) in blood plasma increased as fishmeal intake increased.

The digestion by cattle of silage-containing diets fed at two dry matter intakes. 1. Digestion of organic matter and nitrogen.

In a 4 X 4 Latin square experiment four cattle were given in two meals per d diets consisting of (g/kg dry matter (DM)) 500 barley, 400 grass silage and 100 soya-bean meal. The diets were given at either 1.15 (L) or 2.3 times (H) maintenance energy requirements and the soya-bean meal was either untreated (U) or formaldehyde-treated (T). A 24 h collection of duodenal digesta and a 7 d collection of faeces were made using chromium sesquioxide for flow estimation and 35S as a marker of microbial nitrogen entering the small intestine. Samples of rumen fluid were also taken for estimation of rumen pH, ammonia and volatile fatty acid concentrations. Spot samples of duodenal digesta were obtained after administration of Cr2O3-mordanted silage-fibre and soya-bean meal, to determine the rates of outflow of these markers from the rumen. Similar samples were also obtained after cessation of a continuous intraruminal infusion of ruthenium phenanthroline, 35S and CoEDTA. Incubations of each feedingstuff in porous synthetic fibre (psf) bags were carried out in the rumen and the rates of N disappearance from the bags determined. Increasing DM intake significantly (P less than 0.001) increased the quantities of organic matter (OM), total N and amino acid-N entering the small intestine and amounts subsequently voided in the faeces. Apparent digestibilities of OM and N were unaffected by DM intake; the proportions of total digestible OM digested in the rumen were significantly lower (P less than 0.01) at the higher level of DM intake. Formaldehyde treatment of the soya-bean meal increased the quantities of N entering the small intestine; these increases were not significant. Increased DM intake increased the quantities of both microbial N (P less than 0.001) and undegraded feed N (P less than 0.01) entering the small intestine; HCHO-treatment also significantly (P less than 0.05) increased the quantities of undegraded feed N entering the small intestine. The efficiency of microbial N synthesis within the rumen was not significantly affected by dietary treatments whereas apparent feed N degradability was reduced significantly (P less than 0.05) both by increasing DM intake and by HCHO-treatment of the soya-bean meal. Rates of disappearance of N from psf bags in the rumen were different for different feedingstuffs. However, for a given feedingstuff, the rate of N disappearance was not affected by the diets fed.(ABSTRACT TRUNCATED AT 400 WORDS)

Fungi associated with the spoilage of stored yam chips and flour in Nigeria

AbstractA study was carried out to investigate the organisms associated with the spoilage of yam chips and flour in many locations in 5 states of Nigeria. Monilinia fructicola, Aspergillus flavus, A. fumigatus, A. niger, Penicillium expansum, P. wortmanni, P. duponti, P. funiculosum, Rhizopus sexualis, Piricularia sp., Cladosporium cucumerinum, Helminthosporium sp. and Mucor sp. were isolated and found to cause spoilage of the yam products. Araecerus fasciculatus, Tribolium castaneum and Ahasverus advena were found on the yam chips as infesting insects. The yam chips or flour were either contained in exposed baskets or sealed in fibre bags in the market stalls. A. fumigatus had the highest occurrence. Most of the fungi were found not to sporulate heavily at a temperature of 10–15 °C while only spores of A. fumigatus, A. flavus and C. cucumerinum germinated at 32.5% relative humidity.

The effect of some pre-ensiling treatments on silage composition and nitrogen disappearance in the rumen

Ryegrass, harvested before ear emergence, was ensiled in triplicate in laboratory silos with and without pre-ensiling treatments. These were: 4.7 M sulphuric acid (39 and 79 g kg −1 DM); formalin (28 and 58 g kg −1 DM); ‘Add-F’ (22.5 M formic acid; 36 and 71 g kg −1 DM); formalin (28 and 58 g kg −1 DM); ‘Farmline’, a commercial additive containing acids and formalin (31 g kg −1 DM); heat (30 and 60°C for 1 h); and Lactobacillus plantarum inoculum + glucose (4.6 g kg −1 DM). The ensilage period was 120 days. Samples of each silage were incubated, in artificial fibre bags, in the rumens of four Hereford-cross steers fitted with permanent rumen cannulae. Total nitrogen (TN) disappearance was measured after incubation periods of 1, 2, 4, 7, 12 and 24 h. Hydrochloric acid and the heating pre-treatments had no significant effect ( P > 0.05) on the pH, water-soluble carbohydrates and fermentation acid values compared with those of the control. Fermentation acid production was suppressed to an increasing extent by formalin (28 g kg −1 DM), sulphuric acid (79 g kg −1 DM), formic acid (36 g kg −1 DM), formalin (58 g kg −1 DM) and formic acid (71 g kg −1 DM). The application of L. plantarum + glucose increased fermentation acids from 90.3 g kg −1 DM in the control to 227 g kg −1 DM, owing to a 10-fold increase in lactic acid content from 21.7 to 202 g kg −1 DM. All treatments, with the exception of 30°C heating, produced silages with significantly ( P < 0.001) more total nitrogen as protein than the control. This ranged from 334 g kg −1 TN (60°C heating) to 748 g kg −1 TN (formalin; 58 g kg −1 DM). All treatments significantly ( P < 0.05) reduced TN loss, compared with the control silage values, after a 7-h incubation period in the rumen. After 24 h, however, TN disappearance from the treated silages was not significantly different from that of the control with the exception of the two silages treated with formalin alone. With these silages, the proportion of TN disappearing was 55.0 and 40.0% for the low and high application rates, respectively, compared with a value of 74.0% for the control.

Direct estimation of the extent of contamination of food residues by microbial matter after incubation within synthetic fibre bags in the rumen

The artificial fibre bag technique has been widely used in studies of forage dry-matter digestibility (Van Keuren &amp; Heinemann, 1962) and of the release of a range of plant constituents during fermentation in the rumen (Playne, McLeod &amp; Dekker, 1972). More recently, the technique has been promoted as a simple means of estimating the rate and extent of food protein degradability in the rumen (θrskov &amp; Mehrez, 1977; Mathers, Horton &amp; Miller, 1977).

Protein degradation and optimum urea concentration in cereal-based diets for sheep.

1. Early-weaned lambs were used to estimate the concentration of urea required to give the maximum intake and utilization of maize or barley with either a high (HPB) or low (LPB) protein content. 2. Approximately the same concentration of urea (7--11 g urea/kg feed) was required for maximum intake and feed utilization of both HPB and LPB. With maize there was no increase in intake, live weight gain, digestion and feed conversion as a result of adding more than 7 g urea/kg. 3. The proportion of protein degraded in the rumen was estimated by the synthetic fibre bag technique to be 0.69, 0.82 and 0.54 for HPB, LPB and maize respectively. The similarity in concentration of urea required for optimum utilization of LPB AND HPB might be explained by differences in the extent of degradation of protein in the rumen, but the lower concentration of urea required for maize cannot be similarly explained. 4. From estimates of yield of microbial protein in the rumen, the extent of rumen fermentation and the measured extent of protein degradation, theoretical requirements for urea were calculated and compared with other predictions and with the experimentally determined values. For barley, predicted values agreed reasonably well with experimental ones, but for maize all values, including those derived by a new system adopted by the Agricultural Research Council (ARC) Working Party, were too high.

A study of artificial fibre bag technique for determining the dig estibility of feeds in the rumen

SUMMARYThe artificial fibre bag technique was evaluated for assessing the proportions of dietary D. M. and N which disappear in the rumen. The most important factor determining the variability in disappearance from bags incubated together was the sample size in relation to bag size. For incubation of 5 g air dry feed, a bag size of 17 ✗ 9 cm was found to be adequate. There were also variations in substrate disappearance between animals and between days of incubation. It was estimated that three sheep and the measurement of substrate disappearance twice were necessary in order to obtain acceptable repeatability.The technique was found to be satisfactory as a simple and rapid guide for measuring nutrients disappearance in the rumen such as protein degradation and carbohydrate fermentation. It has been used in subsequent work to measure the effect of features of the rumen environment, such as pH and NH3 concentration, on rate of fermentation.