M. L. He

Effects of essential oils on proteolytic, deaminative and methanogenic activities of mixed ruminal bacteria

The objective of this study was to evaluate in vitro the effects of three essential oils (EO) [cinnamon leaf (250 mg L-1), garlic oil (100 and 250 mg L-1), and juniper berry oil (20 mg L-1)] and tw...

Cinnamaldehyde in feedlot cattle diets: Intake, growth performance, carcass characteristics, and blood metabolites

Cinnamaldehyde (CIN), a natural chemical compound found in the bark of cinnamon trees, can alter rumen fermentation by inhibiting selected ruminal microbes, and consequently, may improve growth performance and feed efficiency of animals. The objective of this study was to evaluate the effects of supplementing the diet of feedlot cattle with CIN on intake, growth performance, carcass characteristics, and blood metabolites. Seventy yearling steers (BW = 390 +/- 25.2 kg) were assigned to a randomized complete block design with 5 treatments: control (no additive), monensin (MO; 330 mg*steer(-1)*d(-1)), and 400, 800, or 1,600 mg of CIN*steer(-1)*d(-1). At the start of the experiment, steers were blocked according to BW and assigned to 14 blocks of 5 cattle, with cattle within block assigned to treatments. The diets consisted of 9% barley silage, 86% dry-rolled barley grain, and 5% supplement (DM basis). Dry matter intake responded quadratically (P = 0.03) to CIN supplementation with 13% more feed consumed for steers fed CIN (mean of 3 CIN levels) compared with those fed control during the first 28 d of the experiment, and with a tendency of 4% increase over the entire experiment. The ADG (kg/d) tended to respond quadratically (P = 0.08) to CIN supplementation during the first 28 d, but was not affected over the entire experiment (112 d). Feed efficiency (G:F) linearly declined (P = 0.03) during the first 28 d with CIN supplementation and was quadratically affected between d 29 to 56 and d 85 to 112 by CIN dose. Supplementation of MO did not affect (P > 0.15) DMI or growth performance at any time during the experiment. Serum NEFA concentrations were reduced (P = 0.05) by 35, 29, 30, and 22%, respectively, on d 56, 84, 112, and overall with CIN supplementation. Concentrations of serum amyloid A were reduced on d 28 by 56, 60, or 56% for 800 mg of CIN, 1,600 mg of CIN, and MO, respectively, compared with control. Plasma concentrations of lipopolysaccharide binding protein were linearly decreased (P = 0.05) with increasing CIN supplementation on d 28. Results indicate that supplementing a feedlot finishing diet with a small dose of CIN ameliorated feed intake during the initial month but had minimal effects on ADG, feed efficiency, and carcass traits over the entire experiment. Including CIN in the diet of feedlot cattle, particularly early in the feeding period, may help promote intake and reduce the effects of stress.

Effects of increasing concentrations of glycerol in concentrate diets on nutrient digestibility, methane emissions, growth, fatty acid profiles, and carcass traits of lambs.

Two experiments were conducted to evaluate the effects of increasing concentrations of glycerol in concentrate diets on total tract digestibility, methane (CH4) emissions, growth, fatty acid profiles, and carcass traits of lambs. In both experiments, the control diet contained 57% barley grain, 14.5% wheat dried distillers grain with solubles (WDDGS), 13% sunflower hulls, 6.5% beet pulp, 6.3% alfalfa, and 3% mineral-vitamin mix. Increasing concentrations (7, 14, and 21% dietary DM) of glycerol in the dietary DM were replaced for barley grain. As glycerol was added, alfalfa meal and WDDGS were increased to maintain similar concentrations of CP and NDF among diets. In Exp.1, nutrient digestibility and CH4 emissions from 12 ram lambs were measured in a replicated 4 × 4 Latin square experiment. In Exp. 2, lamb performance was evaluated in 60 weaned lambs that were blocked by BW and randomly assigned to 1 of the 4 dietary treatments and fed to slaughter weight. In Exp. 1, nutrient digestibility and CH4 emissions were not altered (P = 0.15) by inclusion of glycerol in the diets. In Exp.2, increasing glycerol in the diet linearly decreased DMI (P < 0.01) and tended (P = 0.06) to reduce ADG, resulting in a linearly decreased final BW. Feed efficiency was not affected by glycerol inclusion in the diets. Carcass traits and total SFA or total MUFA proportions of subcutaneous fat were not affected (P = 0.77) by inclusion of glycerol, but PUFA were linearly decreased (P < 0.01). Proportions of 16:0, 10t-18:1, linoleic acid (18:2 n-6) and the n-6/n-3 ratio were linearly reduced (P < 0.01) and those of 18:0 (stearic acid), 9c-18:1 (oleic acid), linearly increased (P < 0.01) by glycerol. When included up to 21% of diet DM, glycerol did not affect nutrient digestibility or CH4 emissions of lambs fed barley based finishing diets. Glycerol may improve backfat fatty acid profiles by increasing 18:0 and 9c-18:1 and reducing 10t-18:1 and the n-6/n-3 ratio.

Substitution of wheat dried distillers grains with solubles for barley grain or barley silage in feedlot cattle diets: Intake, digestibility, and ruminal fermentation1

The objective of this study was to evaluate the effects of substituting wheat dried distillers grains with solubles (DDGS) for barley grain and barley silage on intake, digestibility, and ruminal fermentation in feedlot beef cattle. Eight ruminally cannulated Angus heifers (initial BW 455 ± 10.8 kg) were assigned to a replicated 4 × 4 Latin square design with 4 treatments: control, low (25%), medium (30%), and high (35%) wheat DDGS (DM basis). The diets consisted of barley silage, barley concentrate, and wheat DDGS in ratios of 15:85:0 (CON), 10:65:25 (25DDGS), 5:65:30 (30DDGS), and 0:65:35 (35DDGS; DM basis), respectively. The diets were formulated such that wheat DDGS was substituted for both barley grain and barley silage to evaluate whether wheat DDGS can be fed as a source of both energy (grain) and fiber in feedlot finishing diets. Intakes (kg/d) of DM and OM were not different, whereas those of CP, NDF, ADF, and ether extract (EE) were greater (P < 0.01) and intake of starch was less (P < 0.01) for the 25DDGS compared with the CON diet. The digestibilities of CP, NDF, ADF, and EE in the total digestive tract were greater (P < 0.05) for 25DDGS vs. CON. Ruminal pH and total VFA concentrations were not different (P > 0.15) between 25DDGS and CON diets. Replacing barley silage with increasing amounts of wheat DDGS (i.e., from 25DDGS to 35DDGS) linearly reduced (P < 0.05) intakes of DM and other nutrients without altering (P=0.40) CP intake. In contrast, digestibilities of DM and other nutrients in the total digestive tract linearly increased (P < 0.05) with increasing wheat DDGS except for that of EE. Additionally, with increasing amounts of wheat DDGS, mean ruminal pH tended (P=0.10) to linearly decrease, and ruminal pH status decreased with longer (P=0.04) duration of pH <5.5 and <5.2, and greater (P=0.01) curve area under pH <5.8 and <5.5 without altering (P > 0.19) ruminal VFA and NH(3)-N concentrations. Results indicated that wheat DDGS can be effectively used to replace both barley grain and silage at a moderate amount to meet energy and fiber requirements of finishing cattle. However, when silage content of the diet is low (<10%), wheat DDGS is not an effective fiber source, so replacing forage fiber with wheat DDGS in finishing diets decreases overall ruminal pH status even though the rapidly fermentable starch content of the diet is considerably reduced.

Comparison of wheat or corn dried distillers grains with solubles on rumen fermentation and nutrient digestibility by feedlot heifers

A 5 × 5 Latin square design trial was conducted to evaluate rumen fermentation and apparent nutrient digestibility in 5 rumen-cannulated heifers (420 ± 6 kg) fed a barley-based finishing diet supplemented with 20 or 40% wheat or corn dried distillers grains with solubles (DDGS). The composition of the control diet was 88.7% rolled barley grain, 5.5% supplement, and 5.8% barley silage (DM basis). Increasing the quantity of corn DDGS in the ration resulted in a quadratic decrease in DMI (P = 0.04) and OM intake (P = 0.05). Rumen pH, pH duration, and area under rumen pH thresholds of 5.8 or 5.5 were not affected (P > 0.05) by treatment. Inclusion of wheat DDGS resulted in a quadratic increase (P = 0.05) in pH area below the cutoff value of 5.2, with the most pronounced effect at 20% inclusion. Wheat DDGS linearly increased (P = 0.01) rumen NH(3)-N concentrations. Increasing the inclusion rate of wheat and corn DDGS resulted in quadratic (P = 0.05) and linear (P = 0.04) decreases in rumen propionate, whereas butyrate increased quadratically (P < 0.01) and linearly (P < 0.01), respectively. Feeding wheat DDGS linearly decreased (P < 0.01) DM and OM digestibility values. Inclusion of corn DDGS increased the digestibility values of ether extract (P = 0.05; quadratic response) and CP (P < 0.01; linear response). Neutral detergent fiber digestibility increased in a linear fashion (P = 0.01) as both wheat and corn DDGS inclusion increased, whereas ADF digestibility increased linearly (P = 0.03) for wheat and quadratically (P = 0.02) for corn DDGS. Increased inclusion of wheat DDGS resulted in a linear decrease in GE digestibility (P = 0.01), whereas increasing corn DDGS inclusion linearly increased (P < 0.01) the DE content of the diet. Feeding both wheat and corn DDGS linearly increased (P = 0.01) the excretion of N and P. In summary, replacement of barley grain with up to 40% wheat or corn DDGS did not mitigate rumen pH conditions associated with mild to moderate acidosis in heifers fed a barley-based finishing diet. Supplementing corn DDGS increased nutrient digestibility of all nutrients and, as a result, led to greater DE content. Supplementation of wheat DDGS reduced DM and OM digestibility values, with no effect on DE content. Increased N and P excretion by heifers fed DDGS at 20 or 40% of dietary DM presents a challenge for cattle feeders with respect to nutrient management.

MicroRNAs in bovine adipogenesis: genomic context, expression and function

BackgroundMicroRNAs (miRNAs) are small non-coding RNAs found to regulate several biological processes including adipogenesis. Understanding adipose tissue regulation is critical for beef cattle as fat is an important determinant of beef quality and nutrient value. This study analyzed the association between genomic context characteristics of miRNAs with their expression and function in bovine adipose tissue. Twenty-four subcutaneous adipose tissue biopsies were obtained from eight British-continental crossbred steers at 3 different time points. Total RNA was extracted and miRNAs were profiled using a miRNA microarray with expression further validated by qRT-PCR.ResultsA total of 224 miRNAs were detected of which 155 were expressed in all steers (n = 8), and defined as the core miRNAs of bovine subcutaneous adipose tissue. Core adipose miRNAs varied in terms of genomic location (59.5% intergenic, 38.7% intronic, 1.2% exonic, and 0.6% mirtron), organization (55.5% non-clustered and 44.5% clustered), and conservation (49% highly conserved, 14% conserved and 37% poorly conserved). Clustered miRNAs and highly conserved miRNAs were more highly expressed (p < 0.05) and had more predicted targets than non-clustered or less conserved miRNAs (p < 0.001). A total of 34 miRNAs were coordinately expressed, being part of six identified relevant networks. Two intronic miRNAs (miR-33a and miR-1281) were confirmed to have coordinated expression with their host genes, transcriptional factor SREBF2 and EP300 (a transcriptional co-activator of transcriptional factor C/EBPα), respectively which are involved in lipid metabolism, suggesting these miRNAs may also play a role in regulation of bovine lipid metabolism/adipogenesis. Furthermore, a total of 17 bovine specific miRNAs were predicted to be involved in the regulation of energy balance in adipose tissue.ConclusionsThese findings improve our understanding on the behavior of miRNAs in the regulation of bovine adipogenesis and fat metabolism as it reveals that miRNA expression patterns and functions are associated with miRNA genomic location, organization and conservation.

Altered microRNA expression in bovine subcutaneous and visceral adipose tissues from cattle under different diet

Background MicroRNAs (miRNAs) are a class of molecular regulators found to participate in numerous biological processes, including adipogenesis in mammals. This study aimed to evaluate the differences of miRNA expression between bovine subcutaneous (backfat) and visceral fat depots (perirenal fat) and the dietary effect on miRNA expression in these fat tissues. Methodology/Principal Findings Fat tissues were collected from 16 Hereford×Aberdeen Angus cross bred steers (15.5 month old) fed a high-fat diet (5.85% fat, n = 8) or control diet (1.95% fat, n = 8). Total RNA from each animal was subjected to miRNA microarray analysis using a customized Agilent miRNA microarray containing 672 bovine miRNA probes. Expression of miRNAs was not equal between fat depots as well as diets: 207 miRNAs were detected in both fat depots, while 37 of these were found to be tissue specific; and 169 miRNAs were commonly expressed under two diets while 75 were diet specific. The number of miRNAs detected per animal fed the high fat diet was higher than those fed control diet (p = 0.037 in subcutaneous fat and p = 0.002 visceral fat). Further qRT-PCR analysis confirmed that the expression of some miRNAs was highly influenced by diet (miR-19a, -92a, -92b, -101, -103, -106, -142–5p, and 296) or fat depot (miR-196a and -2454). Conclusions/Significance Our results revealed that the miRNA may differ among adipose depots and level of fat in the diet, suggesting that miRNAs may play a role in the regulation of bovine adipogenesis.

Quantitative Fluorescence In Situ Hybridization of Microbial Communities in the Rumens of Cattle Fed Different Diets

ABSTRACT At present there is little quantitative information on the identity and composition of bacterial populations in the rumen microbial community. Quantitative fluorescence in situ hybridization using newly designed oligonucleotide probes was applied to identify the microbial populations in liquid and solid fractions of rumen digesta from cows fed barley silage or grass hay diets with or without flaxseed. Bacteroidetes, Firmicutes, and Proteobacteria were abundant in both fractions, constituting 31.8 to 87.3% of the total cell numbers. They belong mainly to the order Bacteroidales (0.1 to 19.2%), hybridizing with probe BAC1080; the families Lachnospiraceae (9.3 to 25.5%) and Ruminococcaceae (5.5 to 23.8%), hybridizing with LAC435 and RUM831, respectively; and the classes Deltaproteobacteria (5.8 to 28.3%) and Gammaproteobacteria (1.2 to 8.2%). All were more abundant in the rumen communities of cows fed diets containing silage (75.2 to 87.3%) than in those of cows fed diets containing hay (31.8 to 49.5%). The addition of flaxseed reduced their abundance in the rumens of cows fed silage-based diets (to 45.2 to 58.7%) but did not change markedly their abundance in the rumens of cows fed hay-based diets (31.8 to 49.5%). Fibrolytic species, including Fibrobacter succinogenes and Ruminococcus spp., and archaeal methanogens accounted for only a small proportion (0.4 to 2.1% and 0.2 to 0.6%, respectively) of total cell numbers. Depending on diet, between 37.0 and 91.6% of microbial cells specifically hybridized with the probes used in this study, allowing them to be identified in situ. The identities of other microbial populations (8.4 to 63.0%) remain unknown.

Effects of synthetic conjugated linoleic acid (CLA) or bio-formed CLA as high CLA beef on rat growth and adipose tissue development

Two rat feeding experiments were conducted, concurrently, for 48 d, to determine the effects of feeding synthetic food-grade conjugated linoleic acid (CLA) containing 53% cis 9, trans 11 CLA and 44% trans 10, cis 12 CLA or bio-formed CLA as high CLA beef on adipose tissue development. In exp. 1, 30 (10/diet) weaned male Wistar rats (51 ± 0.65 g) were fed, ad libitum, a control diet, control with sufficient added synthetic CLA to achieve CLA concentrations of 1.1% of diet DM or the control, where the soybean oil in the diet was replaced with sunflower oil. In exp. 2, 20 (10/diet) weaned male Wistar rats (52.5 ± 2.5 g) were fed, ad libitum, diets in which freeze dried beef replaced the casein as the protein source. The meat in the two diets was derived either from steers raised without dietary oil or from beef from steers fed oil to increase CLA content by 144% from 3.36 to 8.20 mg g-1 lipid (high CLA beef). At the end of the experiment the rats were humanely sacrificed and the organs, muscles and the retro...

Dose-response of supplementing marine algae (Schizochytrium spp.) on production performance, fatty acid profiles, and wool parameters of growing lambs.

Microalgae are the original source of docosahexaenoic acid (DHA; 22:6n-3) in the marine food chain, and its inclusion in animal feeds has been considered as a means of increasing the DHA level in foods of animal origin. As such, this study aimed to investigate the effects of supplementing an algal meal, high in DHA derived from Schizochytrium spp. (DHA-G), in the diet of Canadian Arcott lambs, on growth, carcass characteristics, wool production, and fatty acid (FA) profiles of subcutaneous adipose tissues (SAT), perirenal adipose tissues (PAT), and skirt muscle (SM). Forty-four lambs were randomly assigned to dietary treatments. Diets consisted of a pelleted, barley-based finishing diet with DHA-G supplemented at 0, 1, 2, or 3% DM as a replacement for flax oil and barley grain. Feed deliveries and orts were recorded daily. Lambs were weighed weekly and slaughtered once they reached ≥ 45 kg live weight. Carcass characteristics, ruminal pH, and liver weights were determined at slaughter. Wool yield was determined on mid-side patches of 100 cm(2) shorn at d 0 and on the day before slaughter (d 105 or 140). Dye bands were used to determine wool growth, fiber diameter, and staple length. Adipose tissues and SM samples were taken at slaughter and analyzed for FA profiles. Data were analyzed using mixed procedure in SAS with orthogonal contrasts testing for linear, quadratic, or cubic responses to increasing levels of DHA-G. Daily DMI, ADG, and G:F were similar as were wool quality and yield (P > 0.05). Carcass characteristics were generally unaffected (P > 0.05), except for body wall thickness (mm), which showed a quadratic response (P = 0.01) with increasing DHA-G. The concentration of eicosapentaenoic acid (EPA; 20:5n-6; mg/100 g fresh tissue) linearly increased (P < 0.001) with DHA-G in both adipose tissues and responded quadratically in SM (P = 0.05). Similarly, DHA (mg/100 g fresh tissue) increased linearly (P < 0.01) with DHA-G in all tissue types (P < 0.001). Supplementing DHA-G decreased (P < 0.001) the n-6:n-3 ratio in all tissues. No effects (P ≥ 0.05) on PUFA or SFA were observed across the 3 tissues, with no response (P ≥ 0.10) in the SFA:PUFA ratio in either SM or SAT; however, the SFA:PUFA ratio linearly decreased in PAT (P = 0.01) as DHA-G increased. These results indicate that DHA-G can be successfully included in the diets of growing lambs, up to 3% DM, with the potential to improve carcass characteristics and the FA profile of adipose tissue and muscle.