Rate Of Dry Matter Degradation Research Articles

Rumen fermentation and forage degradability in dairy cows offered perennial ryegrass, perennial ryegrass and white clover, or a multispecies forage

An experiment was conducted to compare the rumen fermentation and degradability of three forage treatments. A perennial ryegrass (PRG; Lolium perenne), perennial ryegrass and white clover (Trifolium pratense) (PRGWC) and multispecies forage (MULTI), containing two grass species; perennial ryegrass and timothy (Phleum pratense); two clover species; white clover and red clover (Trifolium repens); and two herb species; chicory (Cichorium intybus) and plantain (Plantago lanceolata), were compared. Six rumen fistulated lactating dairy cows were used in a replicated 3 × 3 Latin square experiment consisting of 3 periods lasting 21-days. Cows were allowed ad libitum access to fresh forage and offered 2.71 kg DM concentrate each day. During days 1 – 14 of each period, cows were acclimatized to dietary treatments before entering a 7 – day sampling period. Indwelling rumen pH probes were inserted into the rumen of each cow on day 15 and 16. Rumen fluid samples were taken on day 18 every 2 h for rumen volatile fatty acid and ammonia nitrogen (NH3N) analysis. Forage dry matter (DM) and crude protein (CP) degradability was assessed via in sacco incubation beginning on day 19 of each period. Treatment had no effect on dry matter intake (DMI) or milk yield. There was no difference in mean rumen pH between treatments. The rumen pH of cows offered MULTI was below pH 6.0 for a higher percentage of time than the other treatments, however the concentration of acetic acid in the rumen of cows was similar between treatments. Effective degradability (ED) of DM was higher (P = 0.003) for MULTI (0.77) compared to PRG (0.68) and PRGWC (0.66). The soluble CP fraction of MULTI and PRGWC was significantly lower than that of PRG (P = 0.007), though PRGWC had the highest rumen ammonia concentration of all treatments (P = 0.002). MULTI had the highest ED and rate of DM degradation in the rumen, and lowest soluble CP of all treatments. Multispecies forages can support milk production in lactating dairy cows; however, care must be taken to ensure adequate dietary NDF due to the low fiber concentration and highly degradable nature of the forage.

Effects of cellulase and Lactiplantibacillus plantarum on the fermentation quality, microbial diversity, gene function prediction, and in vitro rumen fermentation parameters of Caragana korshinskii silage

In the present study, we investigated the effects of cellulase and Lactiplantibacillus plantarum (L. plantarum) on the fermentation quality, microbial diversity, gene function prediction, and in vitro rumen fermentation parameters of the Caragana korshinskii (C. korshinskii) silage. The experimental treatment groups included control (CK), cellulase (C), L. plantarum (L), and cellulase + L. plantarum (CL). Triplicate silos were sampled after 14 and 56 days of ensiling. The microbial diversity of C. korshinskii silage at 56 days was analyzed using Illumina MiSeq sequencing technology, and the effects of C. korshinskii silage on rumen fermentation were evaluated by the in vitro artificial rumen gas production method. The results showed that the addition of cellulose and L. plantarum treatments reduced ammonia-nitrogen (NH3-N), dry matter (DM), neutral detergent fiber (NDF), and acid detergent fiber content during ensiling. Compared with the CK group, higher lactic acid content was observed in the silage of the C and L groups, but the CL group had a higher acetic acid (AA) content. Compared with the CK group, the relative abundance of Lactiplantibacillus significantly increased, but that of Enterococcus, Weissella, Enterobacter, and Pediococcus significantly decreased in all other groups except the C group (p < 0.05). The results of gene function prediction were as follows: pyruvate kinase, 1-phosphofructokinase, and fructokinase were lactate production enzymes, which suggested the association of the high AA content in the CL group to the high abundance of 6-phosphate glucose dehydrogenase. The abundance of H + -transporting ATPase and ATP-binding cassette (ABC) transporters in the L and CL groups was higher than that in the CK groups. Metabolism of terpenoids and polyketides, mismatch repair, DNA replication, nucleotide excision repair, and homologous recombination increased in the CL group compared with those in the CK group. Compared with the CK group, NH3-N and microbial protein content and the degradation rates of DM and NDF increased in the L and CL groups. To conclude, the L and CL groups had increased Lactiplantibacillus abundance, improved fermentation quality, and high DM degradation rates compared with the CK group.

Comparative Study of the Nutritional Value and Degradation Characteristics of Amaranth Hay in the Rumen of Goats at Different Growth Stages.

The objective of this study was to investigate the rumen degradation characteristics of grain amaranth hay (Amaranthus hypochondriacus) at four different growth stages. The aim of this study was to evaluate the nutritional value of grain amaranth hay at different growth stages by chemical composition, in vivo digestibility, and in situ degradability. Three Boer goats with permanent ruminal fistulas were selected in this study. Amaranthus hay at four different growth stages (squaring stage (SS), initial bloom stage (IS), full-bloom stage (FS) and mature stage (MS)) was crushed and placed into nylon bags. Each sample was set up with three replicates, and two parallel samples were set up in fistulas at each time point. The rumen degradation rates of dry matter (DM), crude protein (CP), neutral detergent fibre (NDF) and acid detergent fibre (ADF) were determined at 0, 6, 12, 24, 36, 48 and 72 h. The results were as follows: (1) The concentration of CP in SS was the highest and was significantly higher than that in other stages (p < 0.05), whereas the contents of NDF and ADF gradually increased with the extension of the growing period and reached a maximum in MS; (2)The degradation of CP in the rumen at 72 h of SS and IS was more than 80%. Compared with other stages, the effective degradability of CP was highest in SS (p < 0.05) and reached 87.05% at 72 h, and the degradation rate was the lowest in MS; and (3) The effective degradability of NDF in IS was the highest (p < 0.05) and reached 69.326% at 72 h. The effective degradability of ADF in MS was the highest (p < 0.05) and reached 65.728% at 72 h. The effective degradability of DM and CP in SS was the highest. In conclusion, among the four stages, IS was superior in chemical composition and rumen degradability characteristics.

Productive characteristics, chemical composition, in vitro digestibility, and degradation kinetics of two Brachiaria grasses at different regrowth ages.

The study aimed at the effect of different regrowth ages on chemical, productive, and morphological characteristics, in addition to the kinetics of gas production and in vitro digestibility of grasses of the genus Brachiaria. The treatments consisted of two regrowth ages (21 and 35days) and two grass species (Brachiaria brizantha and B. ruziziensis), in plat with a dimension of 10 × 10 with four replications, totaling 16 plats in a completely randomized design. The regrowth age did not change the leaf:stem ratio of the grasses. Ruziziensis-grass had higher crude protein (CP) content in leaves than Marandu-grass (14.0% versus 10.9% respectively). Marandu-grass leaf had higher NDF content than Ruziziensis-grass (65.0 and 58.3%, respectively) and ADF content (39.6 and 33.2%, respectively). The accumulation rate is high in Marandu-grass regardless of the age of regrowth; however, the in vitro digestibility of dry matter of Ruziziensis-grass is better both in the leaf and in the stem. The regrowth age did not influence the dry matter (DM) and neutral detergent fiber (NDF) in vitro digestibility (ivD) of the leaves. The ivDNDF of leaves of both types of grass were similar. There was an increase in the ivDDM of stem when the regrowth age was 21days. The DM degradation rate was higher in Marandu-grass at both regrowth ages, and the total gas production was higher at 21days. The parameters evaluated in the dual-pool logistic model showed interaction for age and cultivar, except for fractions λ (lag time) and total gas production. Marandu-grass presented a greater volume of gas for the rapidly degradable fraction and a lower degradation rate. There was a significant interaction for the parameters evaluated in the models between ages and grasses. The exponential model showed interaction in all fractions. Grasses had reduced CP content and increased fibrous fraction as a function of age, with no reduction in leaf DM and NDF digestibility. The Ruziziensis-grass has higher digestibility at the regrowth ages evaluated, while Marandu-grass has higher yields. We recommend adjusting the in vitro degradation kinetics by the dual-pool logistic model.

Mixed Fermentation of Lactiplantibacillus plantarum and Bacillus licheniformis Changed the Chemical Composition, Bacterial Community, and Rumen Degradation Rate of Tea Residue

Tea residue, as a byproduct in tea processing, is highly nutritious and can be used as a good raw material for ruminant feed. This study aimed to investigate the effects of Lactiplantibacillus plantarum (L. plantarum) and Bacillus licheniformis (B. licheniformis) mixed fermentation of tea residue mixture (tea residue:wheat bran, 7:3) on chemical composition, bacterial community, and rumen degradation rate. Changes in chemical composition and bacterial community were evaluated after 0 (F0), 1 (F1), 3 (F3), and 5 (F5) days of fermentation. The rumen degradation rate was studied by the in situ nylon bag method. Compared with group F0, acid soluble protein in other groups increased while pH and neutral detergent fiber decreased (p &lt; 0.05). The group F5 was the best. The diversity of bacterial communities in group F0 was significantly lower than those in the other groups (p &lt; 0.05). The relative abundance of phylum Firmicutes and the genus Lactobacillus increased with increasing fermentation time. The rumen degradation rates of dry matter, crude protein, neutral detergent fiber, and acid detergent fiber were increased after fermentation. In conclusion, mixed fermentation of tea residue by L. plantarum and B. licheniformis can ameliorate chemical composition, reduce bacterial community diversity, and improve the rumen degradation rate.

Supplementation of Aspergillus oryzae Culture Improved the Feed Dry Matter Digestibility and the Energy Supply of Total Volatile Fatty Acid Concentrations in the Rumen of Hu Sheep

The objective of the present study was to investigate the effects of feeding different amounts of Aspergillus oryzae culture (AOC) on the degradation rate of various feeds for 24 h, rumen fermentation parameters, microbial community, and blood cell composition of Hu sheep. Sixteen castrated and fattening adult Hu sheep with permanent rumen fistula were randomly divided into four groups (four sheep per group) based on body weight (64.62 ± 5.83 kg). The experiment was repeated for two periods to ensure eight replicates for each treatment, and each period consisted of 28 days, including a 7-d of transition, a 14-d of pre-feeding, and a 7-d of sample collection. The control group (CON) received a basal diet without AOC, and the other groups were fed basal diet supplemented with 10 g/d, 20 g/d, and 40 g/d AOC, respectively, every day before the morning feeding. Supplementation with 20 g/d and 40 g/d AOC significantly increased (P < 0.05) the total volatile fatty acids (TVFAs) content, the molar ratio of butyric acid, and the 24 h dry matter (DM) degradation rate of alfalfa hay and corn straw. When fed 40 g/d AOC, the DM degradation rate of corn germ meal and the relative abundance of Kiritimatiellaeota were significantly increased (P < 0.05), but the ratio of acetic acid to propionic acid (A/P) was significantly reduced (P = 0.04). In conclusion, supplementation with AOC for Hu sheep could improve feed DM digestibility and increase the energy supply of TVFAs concentration in the rumen. Based on the feed conditions of the present study, supplementation 40 g/d of AOC could increase the production efficiency of sheep while higher level have to further investigate.

Nutritional quality of wet distillers’ grains co–ensiled with whole–plant maize and its feeding value for lambs

The high moisture content of wet distillers’ grains with solubles (WDGS) has limited its feeding value despite the relatively high nutritive value. The co–ensiling with whole–plant maize, as a complementary feed, was evaluated for growing lambs by formulating diets whose contents were: whole plant maize silage (WPMS) + sunflower oilcake meal (SOM) (control, WPMS + SOM), whole plant maize silage + dried distillers’ grains (WPMS + DDGS), and whole–plant maize (WPM) co–ensiled with WDGS (WPM – WDGS). Rumen fermentation parameters and in situ degradability of the diets were evaluated using three cannulated Merino wethers in a cross over 3 × 3 Latin square design experiment that lasted 39 days. Concurrently, feed intake and growth performance of South Africa Mutton Merino lambs (29.7 ± 3.6 kg) were evaluated over 45 days. The WPMS + DDGS diet had a lower rate of dry matter degradation (p < 0.05) compared to the WPMS + SOM and WPM–WDGS diets. However, the rapidly fermentable fraction, as well as the progressively fermentable fraction of the diet dry matter, was not different (p > 0.05). No differences in rumen volatile fatty acid, ammonia nitrogen concentration nor rumen pH of the wethers as a result of diet differences were observed. Lambs consuming the WDGS–based diet had a lower average daily intake and average daily gain (p < 0.05) compared to lambs consuming the DDGS and WPMS–based diets. However, the feed conversion ratio was not affected by diet differences (p > 0.05). In conclusion, co–ensiling WDGS with whole–plant maize provides the opportunity for the long–term storage and utilization of WDGS in lamb feeding.

Analysis of Nutrient Composition, Rumen Degradation Characteristics, and Feeding Value of Chinese Rye Grass, Barley Grass, and Naked Oat Straw.

Simple SummaryLimited studies have been reported so far on the rumen degradability characteristic of low-quality forage. In the current study, three low-quality forages (Chinese rye grass, barley grass, and naked oat straw) were selected. Various nutritional parameters such as rumen degradation characteristics, chemical composition and feeding value of three roughages were studied in detail. Among the three roughages, the Chinese rye grass (Leymus chinensis) was superior in terms of rumen degradability characteristics, chemical composition and feeding value.The current study was designed to investigate the chemical composition, rumen degradation characteristics, and feeding value of three roughages commonly used in Asia as ruminant feed, including Chinese rye grass (CRG), barley grass (BG), and naked oat straw (NO). Four Holstein Friesian cows equipped with permanent rumen fistulas were chosen for experimental trials in the current study. The nylon bag method was carried out to measure the crude protein (CP), acid detergent fiber (ADF), ruminal degradability of dry matter (DM), and neutral detergent fiber (NDF). Our analysis revealed that the contents of CP in the CRG (9.0%) and BG (8.9%) were higher than in the NO (5.94%). The contents of NDF in the CRG (64.97%) and NO (63.83%) were lower than in the BG (67.33%), and the content of ADF in the CRG (37.03%) was lower than in the BG (37.93%) and NO (38.28%). The ED values of DM in the NO and CRG were significantly higher (p < 0.001) than in the BG. The effective degradability (ED) values of NDF were the highest in the CRG and lowest in the NO (p < 0.001). In addition, the ED values of ADF were the highest in the CRG and lowest in the BG (p < 0.001). The ED value of CP in the CRG was significantly higher than that in the BG and NO (p < 0.001). The estimated total digestible nutrients (TDN) (54.56%) and DM degradation rate (DDM) (60.06%) of the CRG were higher than those of BG and NO. In addition, the expected DM intake (DMI), estimated relative feed value (RFV), and estimated relative feed quality (RFQ) of the BG were lower than those of the CRG and NO. Altogether, based on our findings, we concluded that the nutritional quality, feeding value and effective rumen degradation rate of CRG were better than of BG and NO.

Effects of homo- and hetero-fermentative lactic acid bacteria on the quality and aerobic stability of corn silage

This study aimed to investigate the effects of homo/heterofermentative lactic acid bacteria (LAB) on the quality of corn silage and its rumen digestibility. Maize (Zea mays strain Xingsiyu No. 10), at the early dough stage, was harvested, chopped, ensiled in vacuum bags, and divided into four groups: (1) control (without added bacteria); (2) with the homofermentative LAB Lactobacillus plantarum and Pediococcus pentosaceus (1:1 mixture, 1 × 105 cfu·g−1); (3) with the heterofermentative LAB Lactobacillus buchneri (1 × 105 cfu·g−1); and (4) with the homo/heterofermentative LAB L. plantarum, P. pentosaceus, and L. buchneri (1:1:1 mixture). At 2, 8, 15, 45, and 60 d of ensiling, nutritional quality, fermentation characteristics, and microbial content were assessed. After 60 d, aerobic stability and rumen digestibility tests were performed. The addition of homo- and (or) hetero-fermentative LAB significantly improved the nutritional quality, fermentation characteristics, and microbial content. Addition of the heterofermenter L. buchneri, with or without the homofermenters L. plantarum and P. pentosaceus, improved aerobic stability. The different LAB inoculants increased the degradation rates of dry matter, acid detergent fiber, and neutral detergent fiber of the corn silage by sheep ruminants. Analysis indicated that L. buchneri yielded the best corn silage.

Effects of dietary supplement sources on the rate and extent of in vitro ruminal degradation of alfalfa-based diets for cattle

Two ruminally cannulated steers [928 ± 25.5 kg body weight (BW)] were fed alfalfa hay at 2.0% of BW and served as donors of rumen fluid. Treatments were early-bud alfalfa (CON) or a combination [dry matter (DM) basis] of 80% early-bud alfalfa with 20% of corn silage (CS), brome grass hay (BGH), soybean hulls (SBH), beet pulp (BP), corn grain (CORN), dried corn distillers’ grains with solubles (DDGS), or wheat middlings (MIDD). Tubes were incubated at multiple time points over a 72 h period and assessed for rate and extent of digestion. Samples were run in duplicate and replicated over 3 d. The potential extent of DM and organic matter (OM) degradation increased (P &lt; 0.001) with CS, SBH, BP, CORN, and DDGS supplementation compared with CON. All supplements except MIDD decreased (P &lt; 0.001) the fractional rates of DM and OM degradation compared with CON, with BGH, SBH, and DDGS having the lowest rates. Supplementation of SBH had the lowest (P &lt; 0.001) initial rate of DM and OM degradation. These data indicate that SBH increases the extent of digestion while reducing the initial rate of degradation, suggesting that SBH has potential to reduce the incidence of frothy legume bloat.

Nutritive value and ruminal degradation of seven Chinese herbs as forage for Tan sheep

ABSTRACT Tan sheep is an indigenous ovine breed of China known for its high meat quality and pleasing taste. Seven herbs of traditional Chinese medicine, namely, Ephedra sinica, Glycyrrhiza uralensis, Caragana korshinskii, Allium mongolicum, Thymus vulgaris, Astragalus membranaceus, and Lespedeza bicolor are commonly grazed by Tan sheep. It has been widely believed that these herbs are of high nutritive value, which may significantly contribute to the high meat quality and distinct flavor of Tan sheep. However, the nutritive values of these herbs have not been evaluated to date. In this study, samples of the seven herbs were collected from the steppe of Yanchi County of Ningxia Autonomous Region of China. The dry matter (DM), crude protein (CP), ether extract (EE), ash (Ash), calcium (Ca), phosphorus (P), neutral detergent fiber (NDF), and acid detergent fiber (ADF) of these herbs were measured using locally cultivated alfalfa as the standard forage. Digestion of the dry matter, neutral detergent fiber, acid detergent fiber, and crude protein in the rumen of Tan sheep was examined using the nylon bag method, in order to evaluate their feeding nutritional value. Our results show that all the seven herbs meet the nutritional needs of ruminants based on the standard forage alfalfa. However, Ephedra, Glycyrrhiza, Caragana, Allium, Astragalus, and Lespedeza have higher nutritive value than Thymus (P < 0.05). According to the ruminal degradation rates of dry matter, neutral detergent fiber, acid detergent fiber, and crude protein, the nutritive value of Caragana, Allium, and Lespedeza is higher than that of Ephedra, Glycyrrhiza, Astragalus, and Thymus (P < 0.05). The overall nutritive value of Allium is the highest among the seven herbs and therefore Allium is recommended to better meet the nutritional needs of Tan sheep.

Nutritional value of dehydrated maize straw ammoniated with urea

SUMMARY This study aimed to evaluate the chemical composition and in situ degradation dry matter of maize straw ammoniated with urea. This was a completely randomized design with five levels of ammoniation (0; 2; 4; 6 and 8% dry matter), with five repetitions. There was effect (P&lt;0.05) of the ammoniation process on the retention of nitrogen in maize straw. For each 1% utilization of urea, we observed a reduction of 1.57% nitrogen retention. The dry matter content was not influenced (P&gt;0.05) by the ammoniation; straw presented a mean value of 75%. In turn, the crude protein content increased (P&lt;0.05) with ammoniation, increasing from 2.74% in the straw without treatment to 10 and 11% with the levels of 6 and 8% urea, respectively. For each 1% urea used, we found a reduction (P&lt;0.05) of 0.65% in the neutral detergent fiber content of maize straw. The acid detergent fiber presented effect (P&lt;0.05) in response to ammoniation. The technique provided a reduction of 0.69% acid detergent fiber for each 1% urea used. For dry matter degradation, we observed an increase in the soluble fraction up to the level of 6% urea. The ammoniation process favored the increase in the dry matter degradation rate of maize straw. It is recommended to conduct the ammoniation process in maize straw with 6% urea.

Effects of sesame meal on intake, digestibility, rumen characteristics, chewing activity and growth of lambs

Two experiments were carried out to determine ruminal degradability of sesame meal (SSM) and its effects on intake, digestibility, rumen parameters, chewing activity, and lamb performance when it replaced soybean meal (SBM). Degradability of dry matter (DM) and crude protein (CP) were determined with the nylon bag technique using three fistulated Zel ewes. The quickly and potentially degradable DM of SSM was lower, but their degradation rates of DM were similar. The quickly degradable protein in the SSM was greater, but the slowly degradable protein of SSM was lower. Potential degradable protein of SBM was greater. The degradation rate of protein was greater in the SSM. Thirty Zel lambs were assigned to five treatments, namely 1) control diet that contained SBM, and 2), 3), 4) and 5) diets that contained 25, 50, 75, and 100% DM of SSM partially or entirely replacing SBM and part of barley grain. There was no difference in the intakes of DM, CP, ether extract (EE), and non-fibre carbohydrate (NFC) among treatments, but neutral detergent fibre (NDF) intake increased when the SSM inclusion rate was increased. Digestibility of DM and EE, passage rate, and total mean retention time differed, but the digestibility of NDF, CP, and NFC, rumen liquid pH and NH 3 -N, passage rate, rumen retention time, eating time, rumination, total chewing activity, DM intake, daily gain, feed conversation ratio, carcass yield and characteristics were not different between treatments. Replacing the SBM with SSM in lamb, improved intake, digestibility, and rumen condition, without reduction in performance and carcass composition. Keywords: Carcass characteristic, feedlotting, lamb, mean retention time, ruminal degradability, soybean meal

Including chicory or plantain in a perennial ryegrass/white clover-based diet of dairy cattle in late lactation: Feed intake, milk production and rumen digestion

In temperate grass-based dairy cattle grazing systems, summer dry conditions can reduce feed availability and quality, and limit milk production. This study reports the effects of including high nutritive value, drought tolerant forbs, chicory (Cichorium intybus L.) and plantain (Plantago lanceolata L.), in a grass-based diet of dairy cattle on intake, milk production and digestion. Forty-two mixed aged cattle in late lactation were randomly allocated to one of five dietary treatments in late summer: perennial ryegrass/white clover (PRG) or ryegrass/white clover (ryegrass) with either chicory (CHI) or plantain (PLA) comprising either 20 or 40% of the daily dry matter intake (DMI). Each treatment group included three cattle with a permanent rumen fistula. The experiment was conducted in an indoor feeding facility to allow individual intakes to be determined and comprised of two independent measurement weeks (Week I and Week II). Over the two measurement weeks, milk production and DMI were similar across diets and there were only minor differences in milk composition. Different effects of including chicory or plantain in the diet were observed, however, between measurement weeks. In Week I, DMI of cattle offered chicory or plantain (forbs) was 10% less than cattle offered PRG (14.7 vs. 16.4kg dry matter (DM)/cow/d, p=0.039) but milk yield (12.3±0.53kg/cow/d) and milk component (fat+protein) yield (1.01±0.05kg/cow/d) were similar across diets. In Week II, DMI was similar (14.2kg DM/cow/d), but cattle offered forbs produced 19% more milk and 17% more milk component yield than those offered PRG. The decrease in DMI and milk production from Week I to II on the PRG treatment was accompanied by a decline in the estimated nutritive value of the ryegrass in the diets. In sacco incubations of fresh forages showed slower rates of DM degradation of ryegrass, relative to chicory or plantain (0.11 vs. 0.22 and 0.19%/h respectively; p<0.001). Total rumen volatile fatty acid concentration and molar proportions measured in 6-hourly spot samplings was similar across diets. Rumen ammonia (NH3) and urine nitrogen (N) concentrations, however, were reduced by up to 37 and 38% in cattle where forb was included in the diet, with greater reductions observed with increasing percentage of forb in the diet (p<0.01). This study suggests that chicory and plantain are suitable species to include in the diet of cattle grazing temperate grass-based swards to maintain or improve milk production in summer. Furthermore, the reductions in rumen NH3 and urine N observed, indicate potential environmental benefits could be gained from feeding forbs.

Effects of sequence of nylon bags rumen incubation on kinetics of degradation in some commonly used feedstuffs in dairy rations

Nowadays, most available information on the degradative behaviour of feeds in ruminants is based on in situ incubation in the rumen, and it is adopted by many feed evaluation systems currently in use for ruminants. However, the outcome of this technique might be affected by many factors such as sequence of nylon bags incubation in the rumen. The objective of current study was to investigate effects of sequence of nylon bag incubation on degradative behavior of dry matter (DM), crude protein (CP), neutral detergent fiber (NDF) and acid detergent fiber (ADF) in some feed ingredients commonly used in dairy rations, including alfalfa haylage, corn silage, corn grain and soybean meal. Four multiparous Holstein lactating cows fitted with permanent ruminal cannulas were used. The nylon bags containing feed samples either were placed in the rumen at once and removed at designated time intervals (all in-gradually out method; AG) or were placed in the rumen at designated time points and retrieved at once (gradually in-all out method; GA). Fractional rate of degradation of potentially degradable fraction, lag time and effective rumen degradability (ED) of DM and CP were significantly higher in the AG compared to the GA method (P<0.05). Fractional rates of DM and CP degradation was higher in alfalfa haylage samples incubated in the rumen using the AG method compared to that using the GA method (0.138 h−1 vs. 0.073 h−1 and 0.002 h−1vs. 0.1125 h−1, for DM and CP, respectively; P<0.05). Due to a higher fractional rate of degradation (Kd) of DM and CP, the ED of DM and CP at different fractional passage rates were higher in the AG than those in the GA method (P<0.05). Potentially degradable fraction and lag time of NDF were higher in the AG method compared to the GA method (P<0.05). Placing all bags in the rumen at once and removing them at designated time intervals compared with introduction of bags in reverse sequence and removing them all at once led to a lower undegradable fraction (U) of NDF in alfalfa (1.8% vs. 4.0%, respectively; P<0.05) and corn silage (3.3% vs. 6.7%, respectively; P<0.05) samples. Potentially degradable fraction of ADF was significantly higher in the AG method compared with the GA method (P<0.05). Bag incubation sequence had profound effects on kinetics of degradation of DM, CP and NDF in situ in the feed samples studied. The effects were more evident in the forages (especially alfalfa haylage) than in the concentrate ingredients namely corn grain and soybean meal. This experiment is the first time to investigate effects of two methods under the same experiment conditions, providing basic data for the determination of ED.

English

Owing to the magnitude and importance of the production of citrus fruits pulp, soybeans and corn in Brazil, considerable research has focused on the main feedstuffs, co-products, and/or byproducts of these crops. The present study is aimed at comparing the ruminal degradability parameters of corn and non-starchy energy sources with high pectin content, including soybean hulls and citrus pulp, through meta-analysis. The experiments were designed to include parameters related to potential and effective degradability of the concentrates of these energy feeds. The database (DB) was composed of 62 treatments obtained from 20 papers. No difference (P>0.05) was observed in any of the ruminal degradability parameters of the dry matter (DM) or crude protein (CP), demonstrating that the total replacement of corn grain by non-starch feed is possible. The degradation rates of DM were 6.78 and 6.14%.h-1 and those of CP were 5.97 and 5.93%.h-1, for corn and non-starch feeds, respectively. Therefore, depending on the cost, corn grain could be substituted by soybean hulls or citrus pulps, which reduce the possibility of the occurrence of metabolic disorders, such as subclinical and/or clinical acidosis, without affecting ruminal fermentation. Key words: Starch, citrus pulps, soybean hulls, energy, pectin, degradability, non-starch feed, acidosis.

Effect of exogenous xylanase on rumen in vitro gas production and degradability of wheat straw.

The objective of this study was to determine effects of xylanase on in vitro gas production (GP) and in sacco degradability of wheat straw. Rumen fluid was obtained from three Mongolian native goats fitted with permanent rumen cannulas. The trial consisted of five doses (0, 0.5, 1.0, 1.5, 2.0 μL/g of substrate) of a commercial xylanase (Dyadic® xylanase PLUS, Dyadic International, Inc., Jupiter, FL, USA). For the in sacco degradability, different levels of xylanase enzyme were added directly onto 2 g of wheat straw in nylon bags and incubated in the rumen for 3, 6, 12, 24 and 48 h to estimate degradability of wheat straw. Total GP increased (P < 0.001) at all times of incubation at intermediate levels of xylanase. Methane production had a similar pattern at 3 and 12 h of incubation; increased linearly at 24 h of incubation, and was unaffected at 6 and 48 h of incubation. Rumen NH3 -N concentration increased linearly at 3 h and the highest values were observed with intermediate enzyme levels. All ruminal volatile fatty acids increased linearly with intermediate levels of the fibrolytic enzyme. The in sacco rate of dry matter degradation decreased linearly (P = 0.020) with increasing enzymes. Intermediate levels of xylanase improved rumen kinetic fermentation and degradability. The outcome of this research indicated that the application of xylanase enzyme could improve in vitro GP fermentation of wheat straw.

Temporal dynamics of fibrolytic and methanogenic rumen microorganisms during in situ incubation of switchgrass determined by 16S rRNA gene profiling.

The rumen microbial ecosystem is known for its biomass-degrading and methane-producing phenotype. Fermentation of recalcitrant plant material, comprised of a multitude of interwoven fibers, necessitates the synergistic activity of diverse microbial taxonomic groups that inhabit the anaerobic rumen ecosystem. Although interspecies hydrogen (H2) transfer, a process during which bacterially generated H2 is transferred to methanogenic Archaea, has obtained significant attention over the last decades, the temporal variation of the different taxa involved in in situ biomass-degradation, H2 transfer and the methanogenesis process remains to be established. Here we investigated the temporal succession of microbial taxa and its effect on fiber composition during rumen incubation using 16S rRNA amplicon sequencing. Switchgrass filled nylon bags were placed in the rumen of a cannulated cow and collected at nine time points for DNA extraction and 16S pyrotag profiling. The microbial community colonizing the air-dried and non-incubated (0 h) switchgrass was dominated by members of the Bacilli (recruiting 63% of the pyrotag reads). During in situ incubation of the switchgrass, two major shifts in the community composition were observed: Bacilli were replaced within 30 min by members belonging to the Bacteroidia and Clostridia, which recruited 34 and 25% of the 16S rRNA reads generated, respectively. A second significant shift was observed after 16 h of rumen incubation, when members of the Spirochaetes and Fibrobacteria classes became more abundant in the fiber-adherent community. During the first 30 min of rumen incubation ~13% of the switchgrass dry matter was degraded, whereas little biomass degradation appeared to have occurred between 30 min and 4 h after the switchgrass was placed in the rumen. Interestingly, methanogenic members of the Euryarchaeota (i.e., Methanobacteria) increased up to 3-fold during this period of reduced biomass-degradation, with peak abundance just before rates of dry matter degradation increased again. We hypothesize that during this period microbial-mediated fibrolysis was temporarily inhibited until H2 was metabolized into CH4 by methanogens. Collectively, our results demonstrate the importance of inter-species interactions for the biomass-degrading and methane-producing phenotype of the rumen microbiome—both microbially facilitated processes with global significance.

Effect of Saccharomyces cerevisiae on alfalfa nutrient degradation characteristics and rumen microbial populations of steers fed diets with different concentrate-to-forage ratios.

Live yeast (Saccharomyces cerevisiae) constitutes an effective additive for animal production; its probiotic effect may be related to the concentrate-to-forage ratio (CTFR). The objective of this study was to assess the effects of S. cerevisiae (SC) on fiber degradation and rumen microbial populations in steers fed diets with different levels of dietary concentrate. Ten Simmental × Local crossbred steers (450 ± 50 kg BW) were assigned to a control group or an SC group. Both groups were fed the same basal diet but the SC group received SC supplementation (8 × 109 cfu/h/d through the ruminal fistula) following a two-period crossover design. Each period consisted of four phases, each of which lasted 17 d: 10 d for dietary adaptation, 6 d for degradation study, and 1 d for rumen sample collection. From the 1st to the 4th phase, steers were fed in a stepwise fashion with increasing CTFRs, i.e., 30:70, 50:50, 70:30, and 90:10. The kinetics of dry matter and fiber degradation of alfalfa pellets were evaluated; the rumen microbial populations were detected using real-time PCR. The results revealed no significant (P > 0.05) interactions between dietary CTFR and SC for most parameters. Dietary CTFR had a significant effect (P < 0.01) on degradation characteristics of alfalfa pellets and the copies of rumen microorganism; the increasing concentrate level resulted in linear, quadratic or cubic variation trend for these parameters. SC supplementation significantly (P < 0.05) affected dry matter (DM) and neutral detergent fiber (NDF) degradation rates (cDM, cNDF) and NDF effective degradability (EDNDF). Compared with the control group, there was an increasing trend of rumen fungi and protozoa in SC group (P < 0.1); copies of total bacteria in SC group were significantly higher (P < 0.05). Additionally, percentage of Ruminobacter amylophilus was significantly lower (P < 0.05) but percentage of Selenomonas ruminantium was significantly higher (P < 0.05) in the SC group. In a word, dietary CTFR had a significant effect on degradation characteristics of forage and rumen microbial population. S. cerevisiae had positive effects on DM and NDF degradation rate or effective degradability of forage; S. cerevisiae increased rumen total bacteria, fungi, protozoa, and lactate-utilizing bacteria but reduced starch-degrading and lactate-producing bacteria.

Extrapolating Bypass Protein Potential of Treated Soybean Meal by In Situ Degradation in Rumen-Fistulated Brahman Cattle

Loss of dietary proteins through microbial fermentation in the rumen may deprive the ruminant animals of valuable supply of amino acids at the intestinal level. This study was conducted to determine the effectiveness of three treatment methods (heat, formaldehyde, and tannic acid) in protecting dietary protein in soybean meal (SBM) from excessive microbial degradation in the rumen to extrapolate its bypass protein potential. The treated SBM samples were incubated for 24, 48, and 72 hr in rumen–fistulated cattle. Results showed that the different treatment methods significantly reduced the rumen degradation of dry matter (DM) in SBM for 24-hr (p&lt;0.01), 48-hr (p&lt;0.01) and 72-hr (p&lt;0.05) incubation, with tannic acid treatment showing the least. In terms of crude protein (CP) degradation,all the treatment methods showed significant reduction in 24-hr (p&lt;0.01) while heat and formaldehyde in 48-hr (p&lt;0.05) incubation, while tannic acid treatment did not differ significantly with that of the untreated, indicating their greater potential than tannic acid in protecting dietary protein from microbial degradation in the rumen. A similar pattern of differences were observed as that of actual values in terms of rates of DM and CP degradation. Overall, heat and formaldehyde treatments can effectively increase the potential of dietary protein to supply the needed amino acids in the intestines.