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This study aimed to identify chemical composition of Thymus kotschyanus essential oil (TKEO) and to evaluate the effects of different doses of TKEO on in vitro gas production, fermentation parameters, acidosis and protozoal population using a completely randomized design with four replicates. Two diets (D1: 100% forage and D2: 30% forage+70% concentrate) were incubated with buffered rumen fluid as fermentation substrates. The plant materials were dried and hydro-distilled in order to obtain their essential oil (EO). The essential oil was analyzed by capillary GC/MS. Gas production (GP144 h) was recorded up to 144 h of incubation. After 24 h, the parameters of apparent in vitro dry matter digestibility (AIVDMD), true in vitro dry matter digestibility (TIVDMD), organic matter digestibility (OMD), partitioning factor (PF) and microbial biomass (MB) were estimated. The main components of TKEO were 25.77% geraniol and 14.85% thymol. Asymptotic GP144 h decreased by TKEO. Addition of TKEO also decreased GP24 h, AIVDMD, TIVDMD and OMD. However, PF and MB increased. Acidosis test was not affected by EO. Inclusion of TKEO decreased the total number of protozoal population. These results indicated that TKEO could potentially be used to modulate rumen fermentation therefore further in vivo research is needed to determine the optimal doses. [ABSTRACT FROM AUTHOR]

The aim of the present study was the estimation of (co) variance components and genetic parameters for body weight of Moghani sheep, using random regression models based on B-Splines functions. The data set included 9165 body weight records from 60 to 360 days of age from 2811 Moghani sheep, collected between 1994 to 2013 from Jafar-Abad Animal Research and Breeding Institute, Ardabil province, Iran. Random regression models were employed to analyze the data. Contemporary groups (year-season of birth - sex-birth type-dam age at the birth) and fixed regression of body weight on age were considered as fixed parts of the models. Random regressions of direct additive genetic, permanent environment, maternal additive genetic and maternal environment were random parts of the models. Linear and quadratic B-Spline functions with two or three coefficients were fitted for fixed and random regressions of the models. A heterogeneous structure of residual variance was considered in five age classes. Variance components were estimated by average information algorithm of restricted maximum likelihood (AI-REML). Different models were compared based on Akaike information criterion (AIC) and Schwarz Bayesian information criterion (BIC). According to both criteria, the best model was a model with quadratic B-Spline functions with 3, 3, 3, 2 and 2 coefficients for fixed regression and random regressions of direct additive genetic, permanent environmental, maternal additive genetic and maternal environmental effects, respectively. According to this model, low to moderate estimates of direct heritability (0.135 to 0.330) and moderate to high estimates of coefficient of permanent environmental effects (0.229 to 0.613) were obtained, while estimates of maternal heritability (0.05 to 0.14) and coefficient of maternal environment (less than 0.01) were low or negligible in all ages. [ABSTRACT FROM AUTHOR]

The effect of grape pomace (Vitis vinifera) and in oak leaf (Quercus libani) tannins by three runs of in vitro gas production on the organic matter digestibility (OMD) and in situ dry matter (DM) and crude protein (CP) disappearance were studied in four sheeps. Polyethylene glycol (PEG) was used to deactivate the tannins. In vitro gas production was recorded at 2, 4, 6, 8, 12, 48, 72, 96 and 120 h of incubation. The chemical composition (g/kg DM) of grape pomace and oak leaf were 940, 940 organic matter (OM); 94, 116 crude protein (CP); 568, 515 neutral detergent fiber (NDFom); 467, 316 acid detergent fiber (ADFom); 242, 93; (lignin (sa)); 70.5, 82 total phenols (TP); 49.7, 73 total tannins (TT); 79, 5.4 condensed tannin (CT) and 40, 70 hydrolysable tannin (HT). Using grape pomace and oak leaf decreased OMD, short chain fatty acids (SCFA), insoluble but fermentable fraction (b) and fermentation rate (c) comparing to control (P<0.05). The addition of PEG increased in vitro gas production (IVGP) at all times of incubation. Kinetics of gas production, OMD and SCFA were also increased by PEG incorporation (P<0.05). The increase in gas production (%) (IGP) in grape pomace (GP) diet was higher than those in oak leaf (OL) diet. The amounts of total protozoa, Isotricha, Dasytricha, subfamily of Entodiniinae, Diplodiniinae and Ophrioscolecinae were decreased by addition of grape pomace and oak leaf. The addition of PEG increased total protozoa, subfamily of Entodiniinae, Diplodiniinae and Ophrioscolecinae populations in grape pomace diet (P<0.05), but increased Isotricha, Dasytricha and subfamily of Diplodiniinae in oak leaf diet (P<0.05). The effective degradability (ED) (g/kg DM) of DM and CP for alfalfa, grape pomace and oak leaf were (646.6, 357.7 and 362.3) and (821, 227.3 and 202), respectively based on in situ fermentation. In conclusion, using grape pomace and oak leaf have positively modified NH3-N concentration and protozoa population. Diet containing grape pomace and oak leaf had lower fermentability than the diet containing alfalfa. Supplementation of PEG in GP and OL diets improved the fermentability of these diets. [ABSTRACT FROM AUTHOR]

The aim of this study was to assess the effect of several doses of spearmint essential oil (SEO; 0, 250, 500, 750 or 1,000 μg ml-1 buffered rumen fluid) on the fermentation kinetic and digestibility using in vitro gas production technique. A total mixed ration (30% roughage: 70% concentrate) was incubated with buffered rumen fluid. In vitro gas production, asymptotic gas production (A), rate of gas production (μ), partitioning factor (PF), microbial biomass (MB), ammonia concentration and digestibility were determined. Increasing the dose of SEO decreased the parameters A and μ. Adding SEO, however, increased PF, ammonia concentration, apparent in vitro dry matter digestibility and true in vitro organic matter digestibility at the lower levels of SEO (250 and 500 μg ml-1). But, at the level of 1,000 μg ml-1, a decrease was observed for these parameters. The increment in PF and digestibility illustrate that SEO has a potential to modulate the rumen fermentation, which may be beneficial (at low doses) for improving nutrient utilization. [ABSTRACT FROM AUTHOR]

Some factors affecting crude protein balance (CPB), as a measure of efficiency, were studied using 2824 records of 501 lactating Holstein cows. The CPB (kg d-1) was calculated as crude protein (CP) intake (kg) minus CP yield (kg). Two different statistical methods including principal components (PCs) and general linear model analyses were used to study the effects of different factors. Crude protein balance had a moderate correlation with PCs 1 (-0.206), 2 (0.318) and 3 (-0.281), which accounted for 65.6% of total variations. Age, parity, lactation stage, pregnancy stage, dry matter intake (DMI), milk yield (MY), fat corrected milk yield (FCM), milk fat percentage (F%), milk lactose percentage (L%), milk fat yield (FY), milk protein yield (PY), milk lactose yield (LY), dietary levels of net energy for lactation (NEL), CP, ruminally undegradable protein (RUP), neutral detergent fiber (NDF) and ether extract (EE) and income over feed cost (IOFC) were correlated to CPB, at least, in one of PCs 1, 2 or 3. In general, linear model analysis CPB was significantly affected by parity and lactation stage and had significant partial linear regression coefficients on DMI (kg d-1), F%, FY (kg d-1), PY (kg d-1), NEL (Mcal kg-1) and dietary levels of CP (%), RUP (%), NDF (%) and EE (%). The quadratic partial regression coefficients of CPB on NEL, CP, RUP and NDF were also significant. The estimates for optimum dietary levels of NEL, CP and RUP for minimizing CPB in the studied population were 1.49 Mcal/kg, 11.29% and 7.58%, respectively. In comparison to NRC's estimates, it seems that, more NEL, RUP and NDF and less CP are needed to minimize protein balance in lactating dairy cows. [ABSTRACT FROM AUTHOR]

Six rumen fistulated adult sheep were used to assess the effect of tannins (hydrolysable tannin; HTs) in oak leaves (Quercus Libani Oliv.) on ruminal fermentation parameters in a change-over design experiment for 28 days in 3 periods. Polyethylene glycol (PEG) was used to deactivate the tannins. The three dietary treatments were control (alfalfa hay, barley grain, wheat bran, wheat straw); OL (oak leave, barley grain, wheat bran and urea) and OL+ 80 g PEG. Animals were held in individual pens and metabolism cages. They were adapted to experimental conditions for 21 days before the commencement of the measurement periods. In each period, the digestibilities of dry matter (DMD), organic matter (OMD), NDF (NDFD), crude protein (CPD) and ruminal parameters (pH, ammonia, bacteria and protozoa population), and microbial protein synthesis were measured using urinary purine derivatives in sheep. The DMD, OMD, NDFD and CPD were decreased by oak leaves and the addition of PEG improved CPD (P<0.05). The ruminal pH values for all diets were within the normal range. Ruminal ammonia was similar among the treatments (p>0.05). Hydrolysable tannins in OL diets decreased (P<0.05) urinary allantoin in comparison to the control diet. Addition of PEG increased (P<0.05) allantoin. The uric acid, xanthine and hypoxanthine excretion in urine were not affected by the diet. Feeding OL diet decreased the microbial N in sheep, whereas addition of PEG improved it. The total protozoa count in sheep offered OL diet declined in comparison to those fed the control diet; however, addition of PEG had no effect on it. Sheep fed OL diet had significantly less cellulolytic and proteolytic bacteria than those fed the control diet (P<0.05), but improved (P< 0.05) with feeding of PEG along with OL. It was concluded that diets containing Q. Libani leaves had lower ruminal fermentability than diet containing alfalfa and that supplementation of PEG in OL diet improved the fermentability. [ABSTRACT FROM AUTHOR]

The aim of this study was to assess the effect of several doses of spearmint essential oil (SEO; 0, 250, 500, 750 or 1,000 μg ml-1 buffered rumen fluid) on the fermentation kinetic and digestibility using in vitro gas production technique. A total mixed ration (30% roughage: 70% concentrate) was incubated with buffered rumen fluid. In vitro gas production, asymptotic gas production (A), rate of gas production (μ), partitioning factor (PF), microbial biomass (MB), ammonia concentration and digestibility were determined. Increasing the dose of SEO decreased the parameters A and μ. Adding SEO, however, increased PF, ammonia concentration, apparent in vitro dry matter digestibility and true in vitro organic matter digestibility at the lower levels of SEO (250 and 500 μg ml-1). But, at the level of 1,000 μg ml-1, a decrease was observed for these parameters. The increment in PF and digestibility illustrate that SEO has a potential to modulate the rumen fermentation, which may be beneficial (at low doses) for improving nutrient utilization. [ABSTRACT FROM AUTHOR]

The objectives of this study were to investigate the effect of a maximum recommended oil supplementation on growth performance, eating behavior, ruminal fermentation, and ruminal morphological characteristics in growing lambs during transition from a low- to a high-grain diet. A total of 21 Afshari male lambs with an initial body weight (BW) of 41.4 ± 9.1 kg (mean ± SD) and at 5−6 months of age were randomly assigned to one of three dietary treatments (n = 7 per group), including (1) a grain-based diet with no fat supplement (CON), (2) CON plus 80 g/d of prilled palm oil (PALM), and (3) CON plus 80 g/d soybean oil (SOY); oils were equivalent to 50 g/kg of dry matter based on initial dry matter intake (DMI). All lambs were adapted to the high-grain diet for 21 d. In the adaptation period, lambs were gradually transferred to a dietary forage-to-concentrate ratio of 20:80 by replacing 100 g/kg of the preceding diet every 3 d. Thereafter, lambs were fed experimental diets for another 22 days. Fat-supplemented lambs had greater DMI, body weight (BW), and average daily gain (ADG), with a lower feed to gain ratio (p < 0.05), compared to CON lambs. The highest differences of DMI between fat-supplemented and CON-lambs were observed in week 3 of the adaptation period (p = 0.010). PALM- or SOY-supplementation lowered DM and NDF digestibility compared with CON (p < 0.05), and SOY caused the lowest organic matter (OM) digestibility compared with CON and PALM lambs (62.0 vs. 67.6 and 66.9; p < 0.05). Ruminal pH was higher for PALM and SOY compared with CON (p = 0.018). Lambs in SOY tended to have the highest ammonia-N concentrations (p = 0.075), together with a trend for higher concentrations of propionic acid, at the expense of acetic acid in ruminal fluid, on the last day of the adaptation period (diet × time, p = 0.079). Fat-supplemented lambs had lower isovaleric and valeric acid concentrations compared with CON on d 40 (diet × time, p < 0.05). PALM and SOY-fed lambs had a longer eating time (min/d and min/kg of DMI), chewing activity (min/d), meal frequency (n), and duration of eating the first and second meals after morning feeding (p < 0.05), and the largest meal size (p < 0.001). Fat supplemented lambs had greater ruminal papillary length (p < 0.05) and width (p < 0.01), and thicker submucosal, epithelial, and muscle layers, compared with the CON (p < 0.01). Blood metabolites were not influenced by dietary treatments (p > 0.05). The results from this study suggest that fat supplementation to high-grain diets may improve the development of ruminal epithelia and modify ruminal fermentation via optimized eating behavior or the direct effect of oils on the ruminal environment, resulting in better growth performance in growing lambs.

This study evaluated the effect of combinations of feed-grade urea and slow-release urea (SRU) on fermentation and microbial protein synthesis within two artificial rumens (Rusitec) fed a finishing concentrate diet. The experiment was a completely randomized, dose-response design with SRU substituted at levels of 0% (control), 0.5%, 1%, or 1.75% of dry matter (DM) in place of feed-grade urea, with four replicate fermenters per dosage. The diet consisted of 90% concentrate and 10% forage (DM basis). The experiment was conducted over 15 d, with 8 d of adaptation and 7 d of sampling. Dry matter and organic matter disappearances were determined after 48 h of incubation from day 9 to 12, and daily ammonia (NH 3 ) and volatile fatty acid (VFA) production were measured from day 9 to 12. Microbial protein synthesis was determined on days 13-15. Increasing the level of SRU quadratically affected total VFA (Q, P = 0.031) and ammonia (Q, P = 0.034), with a linear increment in acetate (L, P = 0.01) and isovalerate (L, P = 0.05) and reduction in butyrate (L, P = 0.05). Disappearance of neutral detergent fiber (NDF) and acid detergent fiber (ADF) was quadratically affected by levels of SRU, plateauing at 1% SRU. Inclusion of 1% SRU resulted in the highest amount of microbial nitrogen associated with feed particles (Q, P = 0.037). Responses in the efficiency of microbial protein synthesis fluctuated (L, P = 0.002; Q, P = 0.001) and were the highest for 1% SRU. In general, the result of this study showed that 1% SRU in combination with 0.6% urea increased NDF and ADF digestibility and total volatile fatty acid (TVFA) production., (© Crown copyright 2020.)

Background: Aflatoxins are fungal secondary metabolites negatively affecting ruminant performance; however, little information is available on their impact on rumen fermentation., Aims: This study aimed at determining the effects of different concentrations of aflatoxin B1 (AFB1) from Aspergillus flavus on in vitro gas production and ruminal fermentation parameters using two experiments (Exp.)., Methods: In Exp. 1, two concentration ranges (0, 0.5, 1, and 1.5 µg/ml of rumen inoculum as low and 0, 5, and 10 µg/ml as high concentration ranges) were used to evaluate AFB1 effect on gas production kinetics using 96-h incubations. In Exp. 2, only the high concentration range was used to investigate AFB1 effects on ruminal fermentation parameters using 24-h incubations., Results: In the low concentration range, the half-time of asymptotic gas production (T 1/2 ) increased and the fractional rate of gas production (µ) decreased linearly with AFB1 dosage (P<0.05). However, in the high concentration range, the asymptotic gas production (A) and T 1/2 decreased; and the lag time (L) and "µ" increased linearly (P<0.001) by increasing the concentrations of AFB1. In Exp. 2, dry matter (DM) and organic matter (OM) disappearance, microbial biomass (MB) and total volatile fatty acids (TVFA) concentrations were depressed, but pH and ammonia-N concentration increased (P<0.01) by increasing the concentrations of AFB1. The pattern of rumen volatile fatty acids (VFAs) was also modified by AFB1, as the propionate proportion increased at the expense of acetate., Conclusion: Aflatoxin B1 had an adverse effect on in vitro ruminal fermentation parameters in high concentration ranges (5 and 10 µg/ml).

This study investigated the effect of treatment of wheat straw using ammonia fiber expansion (AFEX) and exogenous fibrolytic enzymes (Viscozyme) on fiber digestibility, rumen fermentation, microbial protein synthesis, and microbial populations in an artificial rumen system [Rumen Simulation Technique (RUSITEC)]. Four treatments were assigned to 16 vessels (4 per treatment) in 2 RUSITEC apparatuses in a randomized block design. Treatments were arranged as a 2 × 2 factorial using untreated or AFEX-treated wheat straw with or without exogenous fibrolytic enzymes [0 or 500 μg of protein/g straw dry matter (DM)]. Fibrolytic enzymes were applied to straw, prior to sealing in nylon bags. The concentrate mixture was provided in a separate bag within each fermentation vessel. The RUSITECs were adapted for 8 d and disappearance of DM, neutral detergent fiber (NDF), acid detergent fiber (ADF), and crude protein (CP) was measured after 48 h of incubation. Ammonia fiber expansion increased (P < 0.01) the disappearance of wheat straw DM (69.6 vs. 38.3%), NDF (65.6 vs. 36.8%), ADF (61.4 vs. 36.0%), and CP (68.3 vs. 24.0%). Total dietary DM, organic matter (OM), and NDF disappearance was also increased (P ≤ 0.05) by enzymes. Total microbial protein production was greater (P < 0.01) for AFEX-treated (72.9 mg/d) than untreated straw (63.1 mg/d). Total gas and methane (CH4) production (P < 0.01) were also greater for AFEX-treated wheat straw than untreated straw, with a tendency for total gas to increase (P = 0.06) with enzymes. Ammonia fiber expansion increased (P < 0.01) total volatile fatty acid (VFA) production and the molar proportion of propionate, while it decreased (P < 0.01) acetate and the acetate-to-propionate ratio. The AFEX-treated straw had lower relative quantities of fungi, methanogens, and Fibrobacter succinogenes (P < 0.01) and fewer protozoa (P < 0.01) compared to untreated straw. The pH of fermenters fed AFEX-treated straw was lower (P < 0.01) than those fed untreated straw. Both AFEX (P < 0.01) and enzymes (P = 0.02) decreased xylanase activity. There was an enzyme × straw interaction (P = 0.02) for endoglucanase activity. Enzymes increased endoglucanase activity of AFEX-treated wheat straw, but had no effect on untreated straw. The addition of enzymes lowered the relative abundance of Ruminococcus flavefaciens, but increased F. succinogenes. These results indicate that AFEX increased the ruminal disappearance of wheat straw and improved fermentation and microbial protein synthesis in the RUSITEC., (© Crown copyright 2019.)

Sheep adapted to consume tannins rich feeds such as oak leaf (OL) appear to develop defensive mechanisms by their ruminal bacteria against these polyphenols. The capabilities of ruminal isolated tannins resistant bacteria from these animals to ferment a tanniniferous feed (i.e., pistachio hulls, (PH) which were incubated with rumen fluid from Holstein dairy cows was assessed. Six g positive cocci were isolated from the rumen of sheep and the 16s rRNA gene sequences showed them to be closely related to Streptococcus gallolyticus. In three runs of in vitro gas production (GP), the effect of two of the isolates incubated with buffered-ruminal fluid of Holstein cow and PH was evaluated. The GP was recorded from 1 to 96 h of incubation. Incubating either of the isolates with PH caused a significantly higher in vitro gas production, estimated parameters, in vitro organic matter disappearance, metabolisable energy and volatile fatty acids than those without any isolate. The improvement in the ruminal parameters when either of the isolates was used suggested the possible presence of isolated tannins-resistant bacteria (Streptococcus gallolyticus sp.), however, in vivo studies must be conducted to confirm the in vitro results.

Thymol, an important and advantageous component of many essential oils, has been applied as an antimicrobial agent in animals. To increase the duration of action of this compound in ruminants, it was decided here to prepare a controlled release carrier for thymol. Hydroxy propyl methyl cellulose (HPMC) and ethyl cellulose (EC) were used as the matrix polymer here. Mixtures of thymol with eight different ratios of these polymers were then prepared using emulsion solvent evaporation method (F1 to F8). The prepared microparticles were evaluated for production yield, entrapment efficiency, drug content, particle size, drug release behavior, release kinetics (zero order, first order and Fickian matrix diffusion for spheres) and characterized by Fourier transform infrared spectroscopy (FTIR), differential scanning calorimetry (DSC) and scanning electron microscopy (SEM). Mean particle size of microparticles was 1.03 ± 0.02 mm. SEM study revealed that the microparticles were slightly irregular, rough and porous. The formulation with HPMC: EC ratio of 5:1 (F6) showed the highest drug loading (38.8%) and entrapment efficiency (61.2%). This formulation also showed optimum in-vitro drug release. The best fit of release kinetics was achieved with Fickian matrix diffusion for spheres (linear amount released vs t(0.43)). The FTIR spectroscopic and DSC studies show possible interaction between drug and polymers. In this study, thymol was successfully loaded in microparticles prepared from HPMC and EC. These microparticles can be used in further trials to evaluate the effect of slow release thymol on rumen fermentation parameters in ruminants.

Background and Objectives: Essential oils may improve the utilization of nutrients by ruminal microorganisms. The aim of this study was to assess the effect of different doses of ajowan essential oils (AEO) on growth and fibrolytic activity of anaerobic fungi, and generic distribution of ciliated protozoa (in vitro)., Material and Methods: Different doses of AEO (0, 150, 300, 450 and 600 ppm) were added to experimental tubes. The effect of AEO was evaluated on growth and fibrolytic enzyme activity of an anaerobic fungus (Neocalimastix spp.). Generic distribution of ciliated protozoa were evaluated in response to different doses of AEO., Results and Conclusion: The growth of fungus (Neocalimastix spp.) were inhibited and activity of fibrolytic enzymes of fungus were reduced by adding AEO. Also, an inhibitory effect was seen in concentration of ciliated protozoa and some genus were completely disappeared at the doses of 300 ppm and higher. The doses used in this study reduced the fibrolytic activity of the studied rumen microorganisms which is undesirable in practical animal nutrition. Further research is needed to assess the effects of AEO at lower doses on these parameters and also proteolysis and methanogenesis.