scholarly journals Digestibility and rumen fermentation of a high forage diet pre-treated with a mixture of cellulase and xylanase enzymes

2021 ◽  
Vol 51 (3) ◽  
pp. 399-406
Author(s):  
K. Selzer ◽  
A. Hassen ◽  
A.M. Akanmu ◽  
A.Z.M. Salem
Keyword(s):  
Volatile Fatty Acids ◽  
Rumen Fluid ◽  
Latin Square ◽  
Poor Quality ◽  
Gas Production ◽  
Nutrient Digestibility ◽  
Ruminal Fermentation ◽  
Forage Digestibility

Forages play an important role in ruminant animal production worldwide. Unlocking the nutritional potential of poor-quality tropical forages with fibrolytic enzymes would improve forage digestibility and utilization. Using in vitro and in vivo methods this study investigated the effect of pre-treating Smutsfinger hay for 24 hours with a mixture of fibrolytic enzyme (100% cellulase; 75% cellulase: 25% xylanase; 50% cellulase: 50% xylanase; 25% cellulase: 75% xylanase; 100% xylanase and a control with no enzyme) on ruminal fermentation and digestibility of nutrients by sheep. For in vitro fermentation, dry matter, neutral detergent fibre (NDF) degradability and volatile fatty acids (VFA) were determined with standard procedures. The same treatments were used for an in vivo digestibility trial using Merino sheep in a 6 x 6 Latin square design. Feed intake and total tract digestibility were recorded. Rumen fluid samples were collected daily, preserved, and analysed for VFA. The addition of 100% cellulase enzyme to Smutsfinger hay in vitro increased (P <0.05) NDF degradability and gas production compared with the control and inclusion of 100% xylanase enzyme. Both 100% cellulase and xylanase enzymes significantly reduced in vitro end time fermentation pH. A 50:50 mixture of cellulase and xylanase plus enzyme in vivo, increased acetate, total VFA concentration, and higher NDF and ADF digestibility of the test feed compared with the control. Inclusion of a 50-75% mixture of cellulase and 50-25% xylanase enzymes treatment led to higher gas production and butyrate concentration, decreased ruminal pH and improved nutrient digestibility.

The use of degradation characteristics of browse plants to predict intake and digestibility by goats

1993 ◽  
Vol 57 (2) ◽  
pp. 247-251 ◽  
Author(s):  
A. Kibont ◽  
E. R. Ørskov
Keyword(s):  
Regression Analysis ◽  
Rumen Fluid ◽  
Latin Square ◽  
Correlation Coefficients ◽  
Exponential Model ◽  
Gas Production ◽  
Lag Phase ◽  
In Vitro Gas Production

AbstractTwenty-five male goats weighing 16 (s.e. 1-5) kg and aged 15 months were used to measure the dry matter (DM) intake of five browse species namely Acacia albida, Tamarindus indica, Etanda africana, Anogeissus leiocarpus and Sterculia setigera in a growth trial lasting 16 weeks. This was followed by a digestion trial with five goats in a 5 × 5 Latin square with 10 days adaptation and a 5-day measurement period. The degradation characteristics of the browse were measured by incubating samples in nylon bags for 6, 24, 48 and 96 h in the rumens of three sheep fitted with rumen cannulae and given hay plus grass nuts. The exponential model P = a +b(l — ect) was fitted to the data. Rumen fluid from the sheep was also used as an inoculum to incubate the samples in vitro for 3, 6,12, 24, 48, 72 and 96 h. Nylon bag degradability results were compared with in vivo results and in vitro gas production. The mean DM intakes, apparent digestible DM intakes and growth rates were 0·60, 0·62, 0·55, 0·53 and 0·65 kg/day, 0·43, 0·43, 0·35, 0·34 and 0·49 kg/day and 55, 60, 49, 42 and 62 glday for A. albida, T. indica, E. africana, A. leiocarpus and S. setigera respectively. Using the degradation characteristics A, B and c in a multiple regression analysis, the correlation coefficients with DM intake, apparent DM digestibility, apparent digestible DM intake and growth rate were 0·99, 0·88, 0·92 and 0·99 respectively. The inclusion of a lag phase (L) instead of A in the regression analysis improved the prediction of apparent DM digestibility and apparent digestible DM intake. The correlation coefficients between DM loss in nylon bags and in vitro gas production at 6, 24 and 48 h incubation were 0·84, 0·83 and 0·90 respectively. The results indicate that it may be possible to predict DM and apparent digestible DM intakes of browse by goats from the rumen degradation characteristics.

scholarly journals Combining Crude Glycerin with Chitosan Can Manipulate In Vitro Ruminal Efficiency and Inhibit Methane Synthesis

Animals ◽  
2019 ◽  
Vol 10 (1) ◽  
pp. 37
Author(s):  
Anuthida Seankamsorn ◽  
Anusorn Cherdthong ◽  
Metha Wanapat
Keyword(s):  
Volatile Fatty Acids ◽  
Gas Production ◽  
Nutrient Digestibility ◽  
Crude Glycerin ◽  
Control Group ◽  
In Vitro Digestibility ◽  
Ruminal Fermentation ◽  
Ch4 Production ◽  
In Vitro Gas Production

It was hypothesized that the combination of glycerin and chitosan improves ruminal fermentation efficiency via an enhanced propionate (C3) and reduces in vitro CH4 production. This was explored through in vitro gas production with substrates containing crude glycerin, which replaced cassava chips in the studied ration. The experimental design was organized following a 3 × 3 factorial in completely randomized design and the arrangement of treatments were different levels of crude glycerin supplementations 0, 10.5, and 21% of total mixed ration (TMR) and chitosan levels were added at 0, 1, and 2% dry matter (DM) of substrate. Then, 0.5 g of TMR substrates were added into 40 mL bottles, together with respective doses of chitosan and then incubated at 39 °C. The dietary treatments were performed in three replicates within the incubation, and incubations were repeated on three separate days (runs). No interactions were found between crude glycerin and chitosan doses in terms of theoretical maximum of asymptotic gas production (b), rate of gas production (c), the discrete lag time prior to gas production (L), or the cumulative gas production at 96 h of incubation (p > 0.05). Cumulative gas production at 96 h of incubation was similar among the doses of crude glycerin and levels of chitosan, which ranged from 64.27 to 69.66 mL/g DM basis of substrate (p > 0.05). The concentration of ruminal NH3-N after 2 and 4 h of incubation ranged from 14.61 to 17.10 mg/dL and did not change with the addition of crude glycerin with chitosan (p > 0.05). The concentration of CH4 after 2 h of incubation did not change among treatments (p > 0.05), whereas after 4 h of incubation, CH4 synthesis was significantly reduced by enhancing doses of crude glycerin and chitosan (p < 0.05). The combination of 21% of crude glycerin in TMR with 2% chitosan depressed CH4 production as much as 53.67% when compared to the non-supplemented group. No significant crude glycerin and chitosan interaction effect was detected for in vitro digestibility of nutrients after incubation for 12 and 24 h using the in vitro gas production technique (p > 0.05). In addition, no significant changes (p > 0.05) were observed in total volatile fatty acids, acetate (C2) or butyrate content among treatments and between the main effects of crude glycerin with chitosan. At 4 h of incubation, ruminal C3 content and the C2 to C3 ratio changed significantly when crude glycerin and chitosan was added (p < 0.05). The 21% crude glycerin incorporate into TMR, in combination with 2% additional chitosan, increased C3 content by 26.41%, whereas the ratio of C2 to C3 was reduced by 31% when compared to the control group. Propionate concentration increased by 11.75% when increasing levels of chitosan at 2% of substrate, whereas the C2 to C3 ratio decreased by 13.99% compared to the 0% chitosan group. The inclusion of crude glycerin at 21% in TMR diets with chitosan supplementation at 2% enhanced ruminal propionate concentration and reduced methane production without causing any detrimental effect on the gas kinetics or nutrient digestibility.

scholarly journals Rhodaneses Enzyme Addition Could Reduce Cyanide Concentration and Enhance Fiber Digestibility via In Vitro Fermentation Study

Fermentation ◽  
2021 ◽  
Vol 7 (4) ◽  
pp. 207
Author(s):  
Chanadol Supapong ◽  
Anusorn Cherdthong
Keyword(s):  
Volatile Fatty Acids ◽  
Potassium Cyanide ◽  
Insoluble Fraction ◽  
Ammonia Nitrogen ◽  
Gas Production ◽  
Nutrient Digestibility ◽  
Control Group ◽  
In Vitro Digestibility ◽  
Ruminal Fermentation

The use of cyanide-containing feed (HCN) is restricted because it causes prussic acid poisoning in animals. The objective of this study was to see how adding rhodanese enzyme to an HCN-containing diet affected gas dynamics, in vitro ruminal fermentation, HCN concentration reduction, and nutrient digestibility. A 3×4 factorial arrangement in a completely randomized design was used for the experiment. Factor A was the three levels of potassium cyanide (KCN) at 300, 450, and 600 ppm. Factor B was the four doses of rhodanese enzyme at 0, 0.65, 1, and 1.35 mg/104 ppm KCN, respectively. At 96 h of incubation, gas production from an insoluble fraction (b), potential extent (omit gas) (a + b), and cumulative gas were similar between KCN additions of 300 to 450 ppm (p > 0.05), whereas increasing KCN to 600 ppm significantly decreased those kinetics of gas (p < 0.05). Supplementation of rhodanese enzymes at 1.0 to 1.35 mg/104 ppm KCN enhanced cumulative gas when compared to the control group (p < 0.05). Increasing the dose of rhodanese up to 1.0 mg/104 ppm KCN significantly increased the rate of ruminal HCN degradation efficiency (DE) by 70% (p < 0.05). However, no further between the two factors was detected on ruminal fermentation and in vitro digestibility (p > 0.05). The concentration of ammonia-nitrogen (NH3-N) increased with increasing doses of KCN (p < 0.05), but remained unchanged with varying levels of rhodanese enzymes (p > 0.05). The in vitro dry matter digestibility (IVDMD) was suppressed when increasing doses of KCH were administered at 600 ppm, whereas supplementation of rhodanese enzymes at 1.0–1.35 mg/104 ppm KCN enhanced IVDMD (p < 0.05). Increasing doses of KCN affected reduced total volatile fatty acids (TVFA) concentration, which was lowest when 600 ppm was added (p < 0.05). Nevertheless, the concentration of TVFAs increased when rhodanese enzymes were included by 1.0–1.35 mg/104 ppm KCN (p < 0.05). Based on this study, it could be concluded that supplementation of rhodaneses enzyme at 1.0–1.35 mg/104 ppm KCN could enhance cumulative gas, digestibility, and TVAF, as well as lowering ruminal HCN concentration.

scholarly journals Screening of Cyanide-Utilizing Bacteria from Rumen and In Vitro Evaluation of Fresh Cassava Root Utilization with Pellet Containing High Sulfur Diet

2020 ◽  
Author(s):  
Rittikeard Prachumchai ◽  
Anusorn Cherdthong ◽  
Metha Wanapat
Keyword(s):  
Dry Matter ◽  
Volatile Fatty Acids ◽  
Rumen Fluid ◽  
In Vitro Study ◽  
Gas Production ◽  
Ruminal Fermentation ◽  
Cassava Root ◽  
Randomized Design ◽  
Completely Randomized Design

The current work aimed to screen the ruminal cyanide-utilizing bacteria and evaluate the influence of fresh cassava root (FCR) and pellets containing high sulfur (PELFUR) on cyanide content, kinetics of gas, in vitro degradability, and ruminal fermentation. The experiment was conducted in a Completely randomized design (CRD) for a screening of cyanide-utilizing bacteria and the dietary treatments were the level of cyanide at 0, 150, 300, and 450 ppm. A 5 &times; 3 factorial arrangement in a Completely randomized design was used for in vitro study. Factor A was the level of FCR at 0, 260, 350, 440, and 530 g/kg of 0.5 g dry matter (DM) substrate, and factor B was the level of PELFUR at 0, 15, and 30 g/kg DM substrate. Adding different doses of cyanide significantly affected cyanide-utilizing rumen bacterial growth (p &lt; 0.05). Increasing the concentration of cyanide from 0 to 150 and 150 to 300 ppm, resulted in an increase in cyanide-utilizing rumen bacteria of 38.2% and 15.0%, respectively. Increasing the FCR level to more than 260 g/kg of 0.5 g substrate could increase cumulative gas production (p &lt; 0.05), whereas increasing doses of PELFUR from 15 to 30 g/kg increased the cumulative gas production when compared with that of 0 g/kg PELFUR (p &lt; 0.05). Cyanide concentration in rumen fluid decreased with PELFUR (p &lt; 0.05) supplementation. Degradability of in vitro dry matter and organic matter following incubation increased at 12 and 24 h due to PELFUR supplementation with FCR and increased additionally with 15 g/kg PELFUR (p &lt; 0.05) in 440 g/kg FCR. Proportions of the total volatile fatty acids, acetic acid (C2), propionic acid (C3), and butyric acid, as well as the ratio of C2 to C3 among supplementations with FCR (p &lt; 0.05) were significantly different. As the proportion of FCR increased to 530 g/kg of the substrate, the volume of C3 increased by 14.6%. This is the first finding of bacteria in the rumen capable of utilizing cyanide, and cyanide might function as a nitrogen source for bacterial cell synthesis. Inclusion of FCR of 530 g/kg with 30 g/kg PELFUR could increase the cumulative gas production, the bacterial population, the in vitro degradability, the proportion of C3, and the rate of the disappearance of cyanide.

In vitro fermentability and methane production of some alternative forages in Australia

2016 ◽  
Vol 56 (3) ◽  
pp. 641 ◽  
Author(s):  
Z. Durmic ◽  
P. J. Moate ◽  
J. L. Jacobs ◽  
J. Vadhanabhuti ◽  
P. E. Vercoe
Keyword(s):  
Brassica Napus ◽  
Methane Production ◽  
Volatile Fatty Acids ◽  
Plantago Lanceolata ◽  
Ammonia Concentration ◽  
Gas Production ◽  
Ruminal Fermentation ◽  
Brassica Napus L

A study was conducted to examine in vitro ruminal fermentation profiles and methane production of some alternative forage species (n = 10) in Australia. Extent of fermentation was assessed using an in vitro batch fermentation system, where total gas production, methane production, and concentrations in ruminal fluid of volatile fatty acids (VFA) and ammonia were measured. Forages varied in their fermentability, with highest total gas, methane, VFA and ammonia production recorded from selected samples of Brassica napus L. cv. Winfred. Lowest methane production (i.e. 30% less than that formed by the highest-producing one) was observed in Plantago lanceolata L. cv. Tonic and Cichorium intybus L. cv. Choice. Selected plants, including P. lanceolata L. cv. Tonic, Brassica rapa L. cv. Marco, Brassica napus L. cv. Hunter had reduced acetate : propionate ratio and/or ammonia concentration, along with relatively low methane production compared with other species tested, while overall fermentation was not affected. It was concluded that selected novel forages have some advantageous fermentability profiles in the rumen and, in particular, inhibit methane production. However, before these can be recommended as valuable supplementary feedstuffs for ruminants in Australia, further studies are needed to confirm these effects over a range of samples, conditions and in vivo.

scholarly journals In Vitro Fermentation Characteristics and Methane Mitigation Responded to Flavonoid Extract Levels from Alternanthera sissoo and Dietary Ratios

Fermentation ◽  
2021 ◽  
Vol 7 (3) ◽  
pp. 109
Author(s):  
Sukruthai Sommai ◽  
Anusorn Cherdthong ◽  
Chanon Suntara ◽  
Sarong So ◽  
Metha Wanapat ◽  
...  
Keyword(s):  
Methane Production ◽  
Crude Protein ◽  
Volatile Fatty Acids ◽  
Gas Production ◽  
Neutral Detergent Fiber ◽  
Ruminal Fermentation ◽  
Acid Detergent Fiber ◽  
In Vitro Fermentation

Two experiments were conducted under this study: Experiment 1 was to study production yield, chemical composition, and in vitro degradability of Brazilian spinach (Alternanthera sissoo; BS) leaf and leaf + leaf-stalk at various maturity ages of 15, 30, 45, and 60 days after plantation and regrowth and Experiment 2 was to evaluate the effect of flavonoid extract from BS leaf and leaf + leaf-stalk and dietary ratios on ruminal gas production, fermentation characteristics, and in vitro degradability. Experiment 1 showed that maturity ages after planting and regrowth increased, the yield significantly increased. Increasing maturity ages significantly (p < 0.05) increased neutral detergent fiber and acid detergent fiber content and decreased crude protein content, total flavonoid (TF) content, and degradability for both leaf and leaf + leaf-stalk. Maturity ages from 15 to 30 days after plantation and regrowth resulted (p < 0.05) the highest TF content and degradability for both leaf and leaf + leaf-stalk. Thus, BS leaf and leaf + leaf-stalk samples from 15 to 30 days of age were used for flavonoid extraction and used in the Experiment 2. Experiment 2 was conducted according to a 3 × 5 factorial experiment. Three roughage to concentrate (R:C) ratios at 50:50, 40:60, and 30:70 were used, and five levels of flavonoid extract (FE) at 0, 10, 20, 30, and 40 mg of substrate dry matter (DM) were supplemented. Experiment 2 showed that R:C ratio and FE had an interaction effect only on acetate to propionate ratio. Varying R:C ratios significantly increased (p < 0.05) in vitro DM degradability, total volatile fatty acids (VFA), and propionate (C3) concentration. FE supplementation linearly (p < 0.05) increased total VFA and C3 concentration and decreased methane production and protozoal population. This study could conclude that FE from BS could effectively modulate ruminal fermentation and decrease methane production. However, in vivo study needs to elucidate in order to validate the present results.

scholarly journals In Vitro Incubations Do Not Reflect In Vivo Differences Based on Ranking of Low and High Methane Emitters in Dairy Cows

Animals ◽  
2021 ◽  
Vol 11 (11) ◽  
pp. 3112
Author(s):  
Edward H. Cabezas-Garcia ◽  
Rebecca Danielsson ◽  
Mohammad Ramin ◽  
Pekka Huhtanen
Keyword(s):  
Dairy Cows ◽  
Relative Abundance ◽  
Volatile Fatty Acids ◽  
Anaerobic Fermentation ◽  
Rumen Fluid ◽  
Gas Production ◽  
Rrna Gene ◽  
Ch4 Production

This study evaluated if ranking dairy cows as low and high CH4 emitters using the GreenFeed system (GF) can be replicated in in vitro conditions using an automated gas system and its possible implications in terms of fermentation balance. Seven pairs of low and high emitters fed the same diet were selected on the basis of residual CH4 production, and rumen fluid taken from each pair incubated separately in the in vitro gas production system. In total, seven in vitro incubations were performed with inoculums taken from low and high CH4 emitting cows incubated in two substrates differing in forage-to-concentrate proportion, each without or with the addition of cashew nutshell liquid (CNSL) as an inhibitor of CH4 production. Except for the aimed differences in CH4 production, no statistical differences were detected among groups of low and high emitters either in in vivo animal performance or rumen fermentation profile prior to the in vitro incubations. The effect of in vivo ranking was poorly replicated in in vitro conditions after 48 h of anaerobic fermentation. Instead, the effects of diet and CNSL were more consistent. The inclusion of 50% barley in the diet (SB) increased both asymptotic gas production by 17.3% and predicted in vivo CH4 by 26.2%, when compared to 100% grass silage (S) substrate, respectively. The SB diet produced on average more propionate (+28 mmol/mol) and consequently less acetate compared to the S diet. Irrespective of CH4 emitter group, CNSL decreased predicted in vivo CH4 (26.7 vs. 11.1 mL/ g of dry matter; DM) and stoichiometric CH4 (CH4VFA; 304 vs. 235 moles/mol VFA), with these being also reflected in decreased total gas production per unit of volatile fatty acids (VFA). Microbial structure was assessed on rumen fluid sampled prior to in vitro incubation, by sequencing of the V4 region of 16S rRNA gene. Principal coordinate analysis (PCoA) on operational taxonomic unit (OTU) did not show any differences between groups. Some differences appeared of relative abundance between groups in some specific OTUs mainly related to Prevotella. Genus Methanobrevibacter represented 93.7 ± 3.33% of the archaeal sequences. There were no clear differences between groups in relative abundance of Methanobrevibacter.

Assessment of fermentation characteristics of ruminant foods using an automated pressure evaluation system

1998 ◽  
Vol 22 ◽  
pp. 190-192 ◽  
Author(s):  
Z. S. Davies ◽  
A. E. Brooks ◽  
G. W. Griffith ◽  
M. K. Theodorou
Keyword(s):  
Evaluation System ◽  
Pressure Transducer ◽  
Volatile Fatty Acids ◽  
Rumen Fluid ◽  
Gas Production ◽  
Bicarbonate Buffer ◽  
Electronic Pressure ◽  
Forage Digestibility ◽  
Manual Pressure

Gas production from the in vitro digestion of forage with buffered rumen fluid can be measured and used to determine forage digestibility and fermentation kinetics. Rumen micro-organisms ferment carbohydrate to gases (CO2 and CH4) and volatile fatty acids (VFA). The VFA produced also cause CO2 to be released from the C02-bicarbonate buffer. Theodorou et al. (1994) introduced the principle of measuring gas production by pressure increase using an electronic pressure transducer and sealed gas-tight culture bottles. Gases accumulate in the head space of the culture bottles as fermentation proceeds. The gas is measured and then released at regular intervals throughout the fermentation. This procedure was automated (Davies et al., 1995). The automated pressure evaluation system (APES) has advantages over the manual pressure transducer technique (Theodorou et al., 1994) in that it is less labour intensive and has been shown to be more sensitive to food characteristics (Davies et al., 1995). The APES, used in this work, has been improved to include new switches and a filtering system. It has been used here to determine the fermentation characteristics of various ruminant foods: ryegrass, wheat grain and ryegrass silage.

Inoculation with adapted microbes versus addition of polyethylene glycol as methods to alleviate toxicity of Acacia angustissima leaves in sheep

1999 ◽  
Vol 133 (4) ◽  
pp. 445-454 ◽  
Author(s):  
E. M. SAARISALO ◽  
A. A. ODENYO ◽  
P. O. OSUJI
Keyword(s):  
Polyethylene Glycol ◽  
Nutritive Value ◽  
Rumen Fluid ◽  
Latin Square ◽  
Gas Production ◽  
Rumen Content ◽  
Research Station ◽  
Acacia Angustissima

Methods to alleviate the toxicity of Acacia angustissima (acc. no 15132) were evaluated in vitro and in vivo at ILRI Debre Zeit Research station in Ethiopia in 1997–1998. In an in vitro evaluation, A. angustissima leaves were incubated for 120 h with rumen fluid from Borana steers consuming native hay and cotton seed cake or from free ranging goat and sheep. Addition of polyethylene glycol (PEG, molecular weight (MW) 4000) increased gas production (4·9 v. 13·9 ml/100 mg dry matter (DM)), ammonia concentration (5·2 v. 9·7 mmol/l) and neutral detergent fibre (NDF) digestibility (380 v. 540 g/kg DM). In an in vivo experiment, Ethiopian highland sheep fed native hay and A. angustissima as a supplement (200 g/d) were inoculated with mixed rumen content from sheep gradually adapted on A. angustissima or were given PEG (MW 4000, 100 g/kg supplement) as methods to alleviate toxicity induced by A. angustissima. Sesbania sesban (acc. no 10865) with and without PEG were fed as a control. Effects on intake, apparent digestibility and nitrogen balance were studied in a 5×5 Latin square experiment. DM intake was increased by all the supplements (P<0·001) even though hay intake was slightly reduced compared to hay only (P<0·05). PEG increased intake of A. angustissima compared to inoculation. There were no significant differences in apparent DM or OM digestibility. Apparent nitrogen digestibility tended to be higher with S. sesban than with A. angustissima (P<0·10) and addition of PEG increased it with A. angustissima (P<0·05). Supplements increased ammonia and VFA concentrations and molar proportion of propionate (P<0·05). Supplements tended to increase microbial nitrogen supply (P<0·10) but there were no significant differences in efficiency of microbial synthesis. Supplements increased nitrogen retention (P<0·01) but due to short periods there were no significant differences in the live weights of sheep. All the animals remained healthy during the experiment suggesting that both methods used alleviated the toxicity of A. angustissima. Addition of PEG was more effective than inoculation in increasing intake and nutritive value of A. angustissima.

scholarly journals Effects of dietary exogenous fibrolytic enzymes on ruminal fermentation characteristics of beef steers fed high- and low-quality growing diets1

2019 ◽  
Vol 97 (7) ◽  
pp. 3089-3102 ◽  
Author(s):  
Lucas B Kondratovich ◽  
Jhones O Sarturi ◽  
Carly A Hoffmann ◽  
Michael A Ballou ◽  
Sara J Trojan ◽  
...  
Keyword(s):  
Diet Quality ◽  
Latin Square ◽  
Gas Production ◽  
Nutrient Digestibility ◽  
Beef Steers ◽  
Ruminal Fermentation ◽  
Fibrolytic Enzymes ◽  
Sorghum Grain ◽  
Dietary Treatments

Abstract The effects of dietary pretreatment with fibrolytic enzyme-based cocktail were evaluated in 2 studies: (1) in vitro true digestibility; and (2) intake, digestibility, feeding behavior, and ruminal fermentation of beef steers fed growing diets. For the in vitro assessment, the ruminal inoculum was collected from 2 steers (BW = 543 ± 45 kg; 4-h after feeding; growing diets) and enzymes included or not (Trichoderma reesei fermentation extract; 0.75 µL/g of substrate DM). Within in vitro batches (n = 4), 12 substrates were incubated and in vitro true nutrient digestibility was evaluated. For study 2, 5 ruminally cannulated beef steers (BW = 520 ± 30 kg) were used in a 5 × 4 unbalanced Latin square using a 2 × 2 factorial arrangement of treatments: (a) diet quality (high = HQ; and low = LQ) and (b) enzyme inclusion (0 or 0.75 mL/kg of diet DM). Steers were fed ad libitum during four 21-d periods consisting of 14-d of adaptation and 7-d of collections. An enzyme × substrate was observed (P < 0.01), in which DM, OM, and NDF disappearance of sorghum grain increased with enzymes addition. Addition of enzymes increased (P < 0.01) ADF digestibility for all substrates. No diet quality × enzyme (P ≥ 0.18) was observed for intake variables in study 2. Enzyme-fed steers increased (P ≤ 0.05) intake of DM, digestible DM, NDF, and ADF compared with steers not fed fibrolytic enzymes. Addition of enzyme did not affect (P ≥ 0.28) apparent total tract digestibility of beef steers. Steers fed HQ diets consumed more (P ≤ 0.04) DM, digestible DM and OM, and less (P ≤ 0.03) total and digestible fiber than steers fed LQ diets. Ruminal pH average decreased (P = 0.01) for steers fed HQ or enzyme-fed diets compared with other treatments. A tendency (P = 0.06) toward improved total VFA was observed on enzyme-fed steers with HQ diets, but not for LQ diets. The molar proportion of ruminal propionate increased (P = 0.01) when steers were fed enzyme. Steers fed HQ diets had greater (P < 0.01) propionate and valerate molar proportions, lower (P < 0.01) acetate and acetate:propionate ratio than steers fed LQ diets. In vitro methane and total gas production were not affected (P ≥ 0.50) by dietary treatments. Fibrolytic enzymes positively affected digestion of multiple roughage sources commonly fed to cattle and might have additional benefit when used on unprocessed sorghum grain. Fibrolytic enzymes in beef cattle growing diets stimulated intake and generated positive impacts on ruminal fermentation.

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