Effect of whole-plant corn silage treated with lignocellulose-degrading bacteria on growth performance,rumen fermentation,and rumen microflora in sheep

Lignification of cellulose limits the effective utilisation of fibre in plant cell wall. Lignocellulose-degrading bacteria secrete enzymes that decompose lignin and have the potential to improve fibre digestibility. Therefore, this study aimed to investigate the effect of whole-plant corn silage inoculated with lignocellulose-degrading bacteria on the growth performance, rumen fermentation, and rumen microbiome in sheep. Twelve 2-month-old male hybrid sheep (Dorper ♂ × small-tailed Han ♀) were randomly assigned into two dietary groups (n = 6): (1) untreated whole-plant corn silage (WPCS) and (2) WPCS inoculated with bacterial inoculant (WPCSB). Whole-plant corn silage inoculated with bacterial inoculant had higher in situ NDF digestibility than WPCS. Sheep in the WPCSB group had significantly higher average daily gain, DM intake, and feed conversion rate than those in the WPCS group (P < 0.05). Furthermore, higher volatile fatty acid concentrations were detected in WPCSB rumen samples, leading to lower ruminal pH (P < 0.05). The WPCSB group showed higher abundance of Bacteroidetes and lower abundance of Firmicutes in the rumen microbiome than the WPCS group (P < 0.05). Multiple differential genera were identified, with Prevotella being the most dominant genus and more abundant in WPCSB samples. Moreover, the enriched functional attributes, including those associated with glycolysis/gluconeogenesis and citrate cycle, were more actively expressed in the WPCSB samples than in the WPCS samples. Additionally, certain glucoside hydrolases that hydrolyse the side chains of hemicelluloses and pectins were also actively expressed in the WPCSB microbiome. These findings suggested that WPCSB increased NDF digestibility in three ways: (1) by increasing the relative abundance of the most abundant genera, (2) by recruiting more functional features involved in glycolysis/gluconeogenesis and citrate cycle pathways, and (3) by increasing the relative abundance and/or expression activity of the glucoside hydrolases involved in hemicellulose and pectin metabolism. Our findings provide novel insights into the microbial mechanisms underlying improvement in the growth performance of sheep/ruminants. However, the biological mechanisms cannot be fully elucidated using only metagenomics tools; therefore, a combined multi-omics approach will be used in subsequent studies.     

Modeling density dependence and climatic disturbances in caribou: a case study from the Bathurst Island complex, Canadian High Arctic

Peary caribou Rangifer tarandus pearyi is the northernmost subspecies of Rangifer in North America and endemic to the Canadian High Arctic. Because of severe population declines following years of unfavorable winter weather with ice coating on the ground or thicker snow cover, it is believed that density-independent disturbance events are the primary driver for Peary caribou population dynamics. However, it is unclear to what extent density dependence may affect population dynamics of this species. Here, we test for different levels of density dependence in a stochastic, single-stage population model, based on available empirical information for the Bathurst Island complex (BIC) population in the Canadian High Arctic. We compare predicted densities with observed densities during 1961–2001 under various assumptions of the strength of density dependence. On the basis of our model, we found that scenarios with no or very low density dependence led to population densities far above observed densities. For average observed disturbance regimes, a carrying capacity of 0.1 caribou km⁻² generated an average caribou density similar to that estimated for the BIC population over the past four decades. With our model we also tested the potential effects of climate change-related increases in the probability and severity of disturbance years, that is unusually poor winter conditions. On the basis of our simulation results, we found that, in particular, potential increases in disturbance severity (as opposed to disturbance frequency) may pose a considerable threat to the persistence of this species.     

Influence of added microbial enzymes on energy and protein availability of selected feed ingredients

Addition of enzymes to feed ingredients results in an improved energy availability that reduces the difference between gross and metabolisable energy of the raw material. The level of improvement seen is related to enzyme type and to dosage, and correlates well with the substrate specificity of the various enzymes present. Thus the values found in this study are specific for the enzymes and dosages used. Nitrogen retention is also improved by enzyme addition but this did not show a clear dosage response with all materials. An improved nitrogen retention cannot be directly correlated with protein digestibility but an improved retention of protein may offer the possibility to reduce protein levels in the diet.     

Variation in lignin and cell wall digestibility in caffeic acid O-methyltransferase down-regulated maize half-sib progenies in field experiments

Lignin content and structure were examined in seven caffeic acid O-methyltransferase antisense (COMT-AS) maize progenies and their corresponding normal inbred lines in relation to cell wall digestibility. The seven parental inbreds were chosen for their highly divergent in vitro wall digestibility. Maize plants were grown under field conditions to determine (i) if the positive effect of COMT down-regulation on wall chemistry and digestibility was similar to that previously observed for COMT-AS maize grown in the greenhouse and (ii) to what extent the genetic background was a factor in determining the effect of the transgene. All␣COMT-AS progenies displayed a significant reduction in endogenous COMT activity (14–43% residual activity). In all but one genetic background (F4), the COMT-AS gene resulted in an expected increase in wall digestibility accompanied by changes in lignin composition. These effects varied greatly among parental lines, and independently of the inherent digestibility values in the corresponding non-transformed lines. Curiously, in the highly digestible F4 background, the typical decrease in syringyl (S) unit lignin and a higher frequency of 5-OH guaiacyl lignin resulting from the introduction of the COMT-AS transgene were not observed. Our results indicate that COMT down-regulation via an antisense strategy is an efficient tool for forage maize improvement in the field.     

A new algorithm to characterize biodegradability of biomass during anaerobic digestion: influence of lignin concentration on methane production potential

We examined the influence of fibrous fractions of biomass on biochemical methane potential (BMP) with the objective of developing an economical and easy-to-use statistical model to predict BMP, and hence the biodegradability of organic material (BD) for biogas production. The model was developed either for energy crops (grass, maize, and straw) or for animal manures, or as a combined model for these two biomass groups. It was found that lignin concentration in volatile solids (VS) was the strongest predictor of BMP for all the biomass samples. The square of the sample correlation coefficient (R(2)) from the BMP versus lignin was 0.908 (p<0.0001), 0.763 (p<0.001) and 0.883 (p<0.001) for animal manure, energy crops and the combined model, respectively. Validation of the combined model was carried out using 65 datasets from the literature.     

Effect of nitrogen fertilization and mild water stress on the distribution of nitrogen in tall fescue

Summary An investigation was designed to examine the nature and distribution of nitrogen in tall fescue (Festuca arundinacea Schreb.) as influenced by water regime and N fertility under controlled environment conditions. Three replicates of 10 ppm and 110 ppm N were prepared for both adequately watered and water stress treatments of vegetatively propagated tall fescue. Herbage samples were lyophilized and soluble protein extracted in aqueous buffer and separated from low molecular weight N compounds. Two insoluble fractions (R_I, cellular and structural fragments; R_II, organellar residue, primarily chloroplasts) and two soluble fractions (S_I, soluble protein; S_II, low molecular weight compounds) were characterized by Kjeldahl N and acid-hydrolyzable amino-acid analyses.Mild water stress increased the crude protein (CP) concentration of tall fescue, especially under limited N conditions. Nitrogen was redistributed among the fractions when tall fescue was water stressed, regardless of N level. Under adequate water conditions at both N levels, about 30% of the soluble plant N was found in S_I but under water stress, S_I accounted for 50% of the soluble N. This pattern indicates a conservation of intact, nitrogenous material possibly due to decreased proteolysis under mild water stress conditions. The greatest proportion of total N occurred in fraction R_I, regardless of water level, 10 N being greater than 110 N. Organellar residue (R_II) accounted for about 18.5% of the total N regardless of treatment. Non-protein, non amino acid N concentrations were greatest under 110 N water stress conditions. Nitrate N concentrations contributed to less than one percent of the non-protein non-amino acid nitrogen.Component analysis of N in tall fescue, empirically determined as CP, elucidated the redistribution of nitrogenous constituents in response to N fertilization and water regime which may alter nutritive quality and/or plant survival. Accumulation of low molecular weight N compounds under water stress conditions could relate to animal health and fungal endophyte problems associated with tall fescue.     

Einfluss der stärkeherkünfte gerste,mais und kartoffeln und ihrer rationsanteile auf die nährstoffverdaulichkeit und die energieverwertung bei wiederkäuern

In 9 Versuchsperioden an 4 adulten Ochsen (LM 550 kg) mit Brückenfisteln am Duodenum wurden isoenergetische Futtereinnahmen je Tier und Tag auf dem Ernährungsniveau 1,7 mit Gerstenschrot, Maisschrot bzw. frischen Kartoffeln als Stärkequelle und Anteilen von 10, 25 und 50% der Nettoenergie‐Fett aus diesen Stärketrägern realisiert. 50 ... 80 % der TS‐Einnahmen der Rationen bestanden aus Grastrockengrün (TGF), ca. 10 % aus Trockenschnitzeln. Das TGF lieferte im Mittel 87, 79 und 62 % des Futterrohproteins. Die Futteraufnahme betrug 7,74 ±0,42 (y±s) kg/d. Die energetische Effizienz der mikrobiellen N‐Synthese im Pansen (g N/kg im Pansen wahr fermentierte organische Substanz, WFOS) betrug im Mittel 16,4, wobei die Werte von 10,6 bis 21,4 variierten. Bei einem NFE/RFa‐Verhältnis von 1,7 und 2,1 (Gerste), 1,8 (Kartoffeln) bzw. 2,1 und 3,3 (Mais) erreichte die mikrobielle Effizienz ihr Maximum. Zur Passage an nichtmikrobieller organischer Substanz aus dem Pansen (g/d) und zur duodenalen Flußrate (kg Digesta/kg TS‐ Aufnahme) bestand eine positive Beziehung, zur Fermentationsrate der Kohlenhydrate im Pansen (in %) und zur Menge an WFOS (g/d) ein negativer Zusammenhang. Der duodenale Fluß an Mikroben‐N und Nicht‐NH₃‐N (g/d) war mit der im Pansen scheinbar fermentierten organischen Substanz (SFOS, g/d) negativ, mit der Nicht‐SFOS positiv korreliert. Das Aminosäure (AS) muster des duodenalen Proteins wurde durch die Stärkequelle signifikant beeinflußt. Es wird gefolgert, daß die N‐Umsetzungen in den Vormägen des Rindes von der Stärkeherkunft und dem Konzentrat‐Grobfutterverhältnis beeinflußt werden, wobei zwischen beiden Faktoren Wechselwirkungen vorhanden sind. Die Nettosythese von Mikroben‐N ist nicht nur das Ergebnis des Substratumsatzes im Pansen. Die Passage der unfermentierbaren Substanz beeinflußt signifikant den energetischen Wirkungsgrad der mikrobiellen N‐Synthese und die duodenale AS‐Versorgung.     

Adjustments to nitrogen metabolism during wing moult in Greylag Geese, Anser anser

1. This study examined the nitrogen balance of free-living flightless moulting Greylag Geese, Anser anser , in relation to food quality, nitrogen absorption, food retention time and nitrogen excretion rates.
2. Food intake rates during moult were the same as those before and after the flightless period, but total daily time spent foraging fell by 58% from 9·45 h to 3·96 h. Dropping production during moult was 43%, and mean dropping mass 42% of that before and after moult, suggesting a considerable increase in food passage time through the gut during moult. Nitrogen absorption increased from 25% prior to moult to 47% during moult.
3. At the same time, excreted dry mass uric acid in faecal material fell by 68%, such that the proportion of nitrogen absorbed and retained in the body as a proportion of the nitrogen ingested in food rose from 16% prior to moult to 42% during moult.
4. Based on these significant increases in nitrogen absorption and decreases in nitrogen excretion, geese were able to compensate for reduced food intake and derive sufficient nitrogen from their diet to re-grow flight feathers.     

Nutrient digestibility and prediction of metabolizable energy in total mixed rations for ruminants

The aim of the present study was to determine equations that predict ME in total mixed rations (TMR) based on routine methods. The ME content of 30 TMR for dairy cows was determined based on digestible crude nutrients obtained with wether sheep. Concentrations in the TMR (in g/kg DM) varied between 118 and 234 for crude protein, 26 and 48 for crude lipid, 131 and 250 for crude fibre, 281 and 488 for NDF, and 173 and 304 for ADF. Gas production ranged from 40.7 to 54.1 ml/200 mg DM, and enzymatically degraded organic matter from 652 to 800 g/kg DM. Digestibility [%] ranged from 68.6 to 84.0 for organic matter, from 55.6 to 84.3 for crude lipid, from 55.0 to 77.8 for crude fibre, from 57.6 to 77.0 for NDF and from 53.1 to 79.6 for ADF. ME ranged from 9.6 to 11.9 MJ/kg DM, and NEL from 5.7 to 7.4 MJ/kg DM. ME content was highly correlated with the concentration of both crude fibre and enzymatically degradable organic matter as well as with organic matter digestibility. A multiple regression equation based on crude fibre and crude lipid predicted ME with a reasonable goodness of fit (r² = 0.81; s_y.x = 2.4%). The inclusion of other nutrients, of neutral and acid detergent fibre, neither of gas production did improve the goodness of fit. The best prediction was achieved with inclusion of enzymatically degraded organic matter (r² = 0.90; s_y.x = 1.7%).     

Effects of nitrogen source on crude oil biodegradation

Summary The effects of NH₄Cl and KNO₃ on biodegradation of light Arabian crude oil by an oil-degrading enrichment culture were studied in respirometers. In poorly buffered sea salts medium, the pH decreased dramatically in cultures that contained NH₄Cl, but not in those supplied with KNO₃. The ammonia-associated pH decline was severe enough to completely stop oil biodegradation as measured by oxygen uptake. Regular adjustment of the culture pH allowed oil biodegradation to proceed normally. A small amount of nitrate accumulated in all cultures that contained ammonia, but nitrification accounted for less than 5% of the acid that was observed. The nitrification inhibitor, nitrapyrin, had no effect on the production of nitrate or acid in ammonia-containing cultures. When the culture pH was controlled, either by regular adjustment of the culture pH or by supplying adequate buffering capacity in the growth medium, the rate and extent of oil biodegradation were similar in NH₄Cl- and KNO₃-containing cultures. the lag time was shorter in pH-controlled cultures supplied with ammonia than in nitrate-containing cultures.     

赤腹松鼠能量代谢和营养需要的初步研究

在饲养条件下,赤腹松鼠(Callosciurus erythraeus)每天摄入干物质为7.06—9.91克/只,摄入能最为525.4—562.2千焦耳/千克~0.75每天每只摄入蛋白质:1.26—2.00克,脂肪0.69—2.79克。松鼠对能量、干物质、蛋白质和脂肪的消化率分别为85.7％—89.3％;84.7％—87.0％;75.9％—82.7％和79.1％—94.0％。赤腹松鼠喜食含脂量高的食物,对脂肪的消化能力高于蛋白质。营造种子含脂量高的多种树种混交林,提供松鼠足够的食物,是防止松鼠危害的有效途径。     

The pattern of nutrient and energy utilization,retention and the chemical composition of the body in broilers from hatching to maturity

The change of the body composition, of the energy content, and of the energy and protein balances was studied in male and female broiler chicks from hatching to maturity (about 140 days).

The animals received corn, soybean meal and fish meal based diets which ensured maximal growth.

Correlation were established between the ingested feed and the body evolution both from the point of view of quantity and quality, determining the content of protein, fat, ash, water and energy.

By experiments of digestibility and by comparative slaughterings the energy and protein requirements both for maintenance and for protein and fat synthesis were determined.     

An in vitro nutritive evaluation of olive tree (Olea europaea) pruning residues as affected by cutting regimen

Nutritive values of the branches from Olea europaea trees cut at 25, 50, 75 or 100 cm distance from the tip were evaluated by determination of the in vitro digestible organic matter (IVDOM), metabolizable energy (ME), net energy lactation (NEL), and presence nutritional and anti-nutritional components. The values of nutritive components, nitrogen forms, IVDOM, ME and NEL declined and concentrations of crude fiber and cell wall constituents increased with the increase in cutting length. Total phenols, hydrolysable tannins and condensed tannins amounted to 70, 17 and 0.6 g/kg DM, respectively. The addition of polyethylene glycol (PEG, 6000) to the plant samples incubated with rumen fluid at a ratio of (2:1 PEG:substrate) increased the values of IVDOM, ME and NEL by 40 g/kg DM, 0.59 MJ/kg DM and 0.42 MJ/kg DM, respectively. IVDOM, ME and NEL were negatively correlated with crude fiber and cell wall constituents but positively correlated with nitrogen forms and non-fiber carbohydrates. Olive pruning branches in diameter <3 mm could be used as sources of feeds for small ruminants.     

Anti-nutritional effects of a moderate dose of soybean agglutinin in the rat

This study was conducted to investigate the effects of a moderate dose of purified soybean agglutinin on performance and nitrogen digestibility in rats as well as to determine its effects on the protein, DNA and RNA content of the small intestine and pancreas. Twenty-four Sprague - Dawley rats were randomly allotted into one of four groups for a 10-day nitrogen balance experiment. The four groups of rats were fed 7 g of a casein-cornstarch based diet or a similar diet supplemented with 0.1, 0.2 or 0.4 mg/g purified soybean agglutinin. All experimental diets were adjusted to an identical nutrient level. Dose of soybean agglutinin had no significant effect on rat performance. Incorporation of soybean agglutinin in the diet reduced apparent protein digestibility and the utilization of dietary protein by increasing nitrogen loss from the faeces and urine. Fresh pancreatic weight increased in rats fed soybean agglutinin at a level of 0.4 mg/g in the diet compared to the control, but the dry pancreatic weight and the protein content of the pancreas did not differ among the four groups. However the DNA and RNA content of the pancreas had a tendency to increase with a higher level of soybean agglutinin. The weight of the jejunum and its protein, DNA and RNA content were not significantly affected by soybean agglutinin, but the dry weight and the RNA of the jejunum tended to increase with higher levels of soybean agglutinin in the diet. In conclusion, purified soybean agglutinin, at moderate levels in the rats diet, had negative effects on digestive function, such as nitrogen digestibility, nitrogen retention and nitrogen balance. As the level of soybean agglutinin increased, the effects became more pronounced. Meanwhile, hypertrophy of the pancreas was observed with higher doses of soybean agglutinin incorporation in the diets.     

Genetic modification of lignin concentration affects fitness of perennial herbaceous plants

Populations of four perennial herbaceous species that were genetically modified for altered lignin content (or associated forage digestibility) by conventional plant breeding were evaluated for two agricultural fitness traits, plant survival and plant biomass, in three Northcentral USA environments for more than 4 years. Reduced lignin concentration or increased digestibility resulted in increased winter mortality in two of four species and reduced biomass in one species. Results from other experiment indicate that these apparent genetic correlations may be ephemeral, suggesting that selection for fitness can be successful within high-digestibility or low-lignin germplasm. Results indicate that perennial plants genetically engineered with altered lignin concentration or composition for use in livestock, pulp and paper, or bioenergy production should be evaluated for fitness in field environments prior to use in agriculture. Received: 12 December 2000 / Accepted: 27 February 2001     

Untersuchungen über die Qualität des Futtereiweißes bei Legehennen

Aim of the studies was to attain new scientific findings for the influence of the physiological state of sows (non‐pregnant and pregnant respectively) on energy and nitrogen metabolism. The experiments were carried out according to a 3 x 3 factorial experimental plan with 3 variants of litter number (1, 2 and 4) and 3 variants of energy supply (120, 100 and 80%). Within the variants the non‐pregnant and pregnant sows were fed equally related to the metabolic live weight. The metabolism measurements run from the 1^st to the 115^th experimental and gestation day respectively. The methods of indirect calorimetry and slaughtering technique were applied. The chemical composition of the whole bodies of the non‐pregnant sows was like that of the maternal bodies of the pregnant sows (dry matter 410 g/kg, protein 160 g/kg and fat 210 g/kg). The physiological state for the sows did not influence the nutrients digestibility (OM 77.0 and 76.7%) and the energy metabolizability. About conformable intakes of metabolizable energy (601 and 586 kJ/kg LW ^0,75·d) and of digestible nitrogen (0.77 and 0.75 g/kg LW ^0,75·d) in non‐pregnant and pregnant sows resulted in higher deposition of energy (64 and 79 kJ/kg LW ^0,75·d) and of nitrogen (0.15 and 0.19 g/kg LW ^0,75·d) in the pregnant sows due to energy and nitrogen deposition in the conception products and in the reproductive organs. The energy maintenance requirement and the partial efficiency of the energy utilization for the deposition as well as the nitrogen maintenance requirement and the partial efficiency of the nitrogen utilization for the deposition in the non‐pregnant and the pregnant sows were determined.     

Nutritional Evaluation of Genetically Modified Maize Corn Performed on Rats

The aim of this study was to determine the composition and nutritional value of conventional and transgenic, so-called Roundup Ready (RR) maize with an introduced gene of glyphosate resistance. Crude protein, crude fibre, ash, fat, starch, sugar, amino acids, fatty acid and macroelement levels were determined by chemical analysis. In both maize lines a low level of Ca (0.15g.kg m 1 DM) and of the essential amino acids lysine and tryptophan (2.6 and 1.7g.kg^{m 1} DM, respectively) were observed. In the biological experiment carried out on rats the tested maize lines were the only dietary sources of nitrogen, thus, the experimental diets contained 9% CP in dietary dry matter. In the feeding experiment no significant differences in the protein efficiency ratio (PER) were observed between groups receiving conventional or transgenic maize (1.51 and 1.41, respectively). Also almost equal results were obtained in the balance experiments. Both maize lines revealed a high nitrogen digestibility (84.9 and 84.5%, respectively) and the net protein utilization amounted to 63.5 and 63.2%, respectively. From these results can be concluded that regarding nutrient composition and utilisation, genetically modified (RR) maize is equivalent to isogenic maize.     

Effects of Tasco (a seaweed extract) and heat stress on N metabolism and meat fatty acids in wether lambs fed hays containing endophyte-infected fescue

Wether lambs (n = 27, average BW = 40 kg) were used to test response to forage treated with Tasco-Forage (an extract of the brown kelp Ascophyllum nodosum) prior to conserving, or to direct feeding of the extract (Tasco-EX). Hays made from endophyte (Neoyphodium coenophialum)-infested tall fescue (Festuca arundinacea)-based pasture received 0 or 3 kg of Tasco/ha prior to harvest. Lambs, blocked by weight, were randomly allotted to three diets: (1) control hay, (2) treated hay, and (3) #1 + Tasco-EX fed at 1% of the diet. Hays were low in CP (<7%) so all lambs were fed soybean meal (12% of the diet) in addition to trace mineralized salt. Diets were fed at 1.5% BW to prevent refusals. Total collections (7 d) were made during periods without or with applied heat stress. After each period, rumen contents were obtained to determine pH, NH₃ and VFA. Lambs were sacrificed post-trial. A subset was used to evaluate sensory traits and muscle fatty acids. Lambs were in negative N balance during the study and Tasco treatments did not affect N metabolism. Fecal N tended (P < 0.10) to increase with short duration heat stress causing a concomitant decrease (P < 0.05) in apparent N digestibility (58.6 versus 56.1%; S.E. = 0.7). Urinary N loss decreased (P < 0.001) with heat stress (8.0 versus 5.9 g/d; S.E. = 0.2), resulting in increased (P < 0.001) N retention (−2.1 versus −0.3 g/d; S.E. = 0.2). Apparent OM digestibility was not affected by heat stress but was greater (P < 0.05) for lambs fed Tasco-EX treatment than those fed treated hay. Treatment diets decreased (P < 0.05) ruminal butyrate. Heat stress increased (P < 0.05) acetate and total VFA and decreased (P < 0.01) ruminal pH. A tendency (P < 0.11) of increased 14:1ω5, decreased (P < 0.05) 18:0 and total saturated fatty acids in muscle was observed with Tasco diets. Meat sensory characteristics were not affected by treatment. Tasco may alter some aspects of rumen or lipid metabolism but has no effect on N metabolism or meat sensory characteristics of sheep fed restricted, low-quality diets.