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Simple Summary: Marbling or intramuscular fat deposition in beef is a major determinant of carcass quality and value. Providing high-grain diets during the finishing phase stimulates intramuscular fat deposition, and the carcass quality grade is higher when steers are corn-fed versus grass-fed. This study examined the efficacy of feeding high-concentrate diets for differing times during the post-weaning phase to enhance intramuscular fat deposition and improve carcass quality before forage finishing. Feeding concentrates for 120 day post-weaning enhanced intramuscular fat deposition by altering lipogenic/lipolytic gene expression during the post-weaning phase that was maintained during forage finishing. At slaughter, steers that were fed concentrates for 120 day had higher-quality grades at similar body weights and yield grades than the steers that were fed shorter time periods during the post-weaning phase. The polyunsaturated fatty acid content of the longissimus muscle at slaughter was altered with concentrate feeding post-weaning, but the overall ratio of n-6 to n-3 fatty acids was below the threshold regarded as beneficial for human health. The objectives of this study were to examine the effects of feeding high-concentrate diets post-weaning (PW) prior to forage finishing on (1) changes in ultrasound intramuscular fat deposition and lipogenic/lipolytic gene expression during the post-weaning phase and (2) carcass characteristics and fatty acid composition after forage finishing to 487 kg. Steers were randomly assigned to one of four treatments (PW0, PW40, PW80, and PW120) at weaning to examine the time of high-concentrate feeding prior to forage finishing. The ultrasound intramuscular fat content was greater (p < 0.05) for PW120 compared to those for PW0, PW40, or PW80 at the end of the post-weaning phase. Feeding high concentrates (PW120) up-regulated (p < 0.01) the mRNA expression of fatty acid transporters and lipogenic genes and down-regulated lipolytic genes in the LM compared to PW0. Carcasses from PW120 were graded 83% Choice (p = 0.025), whereas carcasses from other post-weaning treatments (PW0, 40, or 80) were graded 25, 36, and 54% Choice, respectively, at the final harvest. The total fatty acid content of the muscle at slaughter was greater (p = 0.0004) for PW120 than PW0, PW40, and PW80. Feeding high-concentrate diets to steers post-weaning for 120 day enhanced early intramuscular fat deposition without causing major changes to the fatty acid composition of the longissimus muscle after forage finishing. [ABSTRACT FROM AUTHOR]

Consumption of ergot alkaloids during the second half of gestation has been shown to decrease umbilical artery vasoactivity resulting in decreased birth weights. Negative vascular effects of ergot alkaloids are mediated predominantly through serotonergic and adrenergic receptors in other tissues. Vasoactivity of serotonin (5-HT) receptors 5-HT2A and 5-HT1B/1D in umbilical artery and vein from ewes receiving endophyte-infected seed (E + 1.77 mg ergovaline/hd/d) or a control total mixed ration (CON; 0 mg ergovaline/hd/d) tall fescue seed at d-110 and d-133 of gestation was evaluated. Gravid reproduction tracts were collected from ewes. Two-mm sections of umbilical artery and vein were exposed to increasing concentrations of a 5-HT1B/1D agonist and 5-HT2A agonist. The 5-HT1B/1D agonist did not stimulate a contractile response in artery or vein or either gestation time point. 5-HT2A agonist caused large responses in artery with greatest occurring at d-110 and decreasing in magnitude as days of gestation increased (p < 0.05). On d-110 and 133 of gestation, arteries from CON ewes had greater contractile response than arteries collected from E+ ewes (p < 0.05). Veins responded to increasing concentrations of the 5-HT2A agonist. Maximal d-110 vein response was greater than d-133 when exposed to 5-HT2A agonist (p < 0.05). Unlike the artery, veins from E+ ewes had greater d-133 contractile response than CON (p < 0.05). Vascular contractions of umbilical artery and vein are induced by 5-HT2A receptor activity and not 5-HT1B/1D. Umbilical artery 5-HT2A receptor activity was more sensitive to seed treatment and could be responsible for ergot alkaloid-induced intra-uterine growth restriction. [ABSTRACT FROM AUTHOR]

Simple Summary: This research examined the use Texel or Southdown sires on Southdown or Suffolk dams to improve carcass quality and muscle composition in lambs produced on pasture-based systems. Texel-sired lambs had heavier carcasses, larger ribeye areas and individual muscle weights from the loin and leg. Dual energy X-ray absorptiometry was used to rapidly rank carcasses for leanness by dam and sire breeds. Texel-sired lambs had lower, more desirable, rank for carcass leanness and less total carcass fat. Individual muscles of the loin and leg from the various breed combinations were evaluated for fatty acid composition and tenderness. Dam and sire breed influenced fatty acid composition of the muscles. The semitendinosus muscle had the highest total fatty acid content and lowest ratio of n-6 to n-3 fatty acids. Overall, muscles from these lambs finished on pasture with limited grain supplementation were very lean, with high concentrations of polyunsaturated fatty acids and a ratio of n-6 to n-3 fatty acid of below 4:1, which is considered beneficial for human health and reduction of coronary heart disease. The use of Texel sires in pasture-based systems improved carcass leanness and muscle PUFA concentrations without altering tenderness. This study explored the impacts of sire and dam breed on carcass quality and composition in a pasture-based system and the use of DXA to rapidly rank carcasses for leanness. Southdown (SD) and Suffolk (SF) ewes were mated to Texel (TX) or SD rams to produce seventy-nine lambs. Lambs were raised on pasture-based systems with limited grain supplementation. Lamb birth weight was greater (p < 0.01) for TX, regardless of dam breed. Lambing rate was lower (p < 0.01) for SD than SF ewes. Circulating myostatin concentrations were greater (p < 0.05) on d 42 than d 75 or d 110 but did not differ by sire breed. Texel-sired lambs had greater (p < 0.01) carcass weight, ribeye area and quality grade compared to SD-sired. Total and primal fat mass as predicted from DXA was higher (p < 0.05) in carcasses from SD than TX sires. Muscles from TX lambs had greater (p < 0.05) polyunsaturated fatty acid (PUFA) composition than SD-sired. Shear force values were influenced (p < 0.01) by dam breed, muscle cut and postmortem age but not by sire breed. The use of TX sires in pasture-based systems improved carcass leanness and muscle PUFA concentrations without altering tenderness. [ABSTRACT FROM AUTHOR]

Simple Summary: Understanding the relationship between supplementation and animal production requires a systems approach to understand all variables affecting this relationship. Many publications regarding the utilization of consumed supplements have been published, as have studies focused on cattle production response. Supplementation costs strongly influence farm profitability, yet many supplementation strategies aim to supply nutrients to the average of the group, though inter-animal variation within groups can differ vastly meaning both over- and under-supplementation is occurring, potentially decreasing production. Measuring real-time cattle intake is historically labor intensive and typically focuses on total intake instead of individual supplement intake. New precision feeding technologies such as the C-Lock SuperSmart Feeder (SSF, C-Lock Inc., Rapid City, SD, USA) allow for real-time supplement intake data collection in field settings but require adaptation periods to facilitate the usage of these technologies by cattle. New technologies, such as the SSF, offer insight into behavioral information relating to cattle adaptation rates, feeding patterns, and the relationship between supplementation and animal production. The objective of this research was to assess the training and adoption rates of three different groups of cattle (suckling calves, weaned steers, replacement heifers) to the SSF. Supplementation of beef cattle can be used to meet both nutrient requirements and production goals; however, supplementation costs influence farm profitability. Common supplementation delivery strategies are generally designed to provide nutrients to the mean of the group instead of an individual. Precision individual supplementation technologies, such as the Super SmartFeed (SSF, C-Lock Inc., Rapid City, SD, USA), are available but are generally cost prohibitive to producers. These systems require adaptation or training periods for cattle to utilize this technology. The objective of this research was to assess the training and adoption rates of three different groups of cattle (suckling calves, weaned steers, replacement heifers) to the SSF. Successful adaptation was determined if an individual's supplement intake was above the group average of total allotted feed consumed throughout the training period. Suckling calves (n = 31) underwent a 12 d training period on pasture; 45% of suckling calves adapted to the SSF and average daily intake differed (p < 0.0001) by day of training. Weaned steers (n = 79) were trained in drylot for 13 d. Of the weaned steers, 62% were trained to the SSF, and average daily intake differed (p < 0.0001) by day of training. Replacement heifers (n = 63) grazed tall fescue pastures and had access to SSF for 22 d of training. The success rate of replacement heifers was 73%. For replacement heifers, the daily intake did not differ (p < 0.0001) by day of training. Results indicate production stage may influence cattle adaptation to precision technologies. [ABSTRACT FROM AUTHOR]

The predominant ergot alkaloid found in wild type endophyte-infected tall fescue grass is ergovaline. Ergovaline is a potent vasoconstrictor in livestock that consume it. Previous research has shown that ergovaline can bind serotonin (5-HT) receptors and blood vessels exposed to ergovaline become unresponsive to subsequent 5-HT exposure. Serotonin can stimulate vascular contraction or relaxation depending on the receptor subtype targeted. The objective of this experiment was to evaluate 5HT as vasorelaxant in the ovine saphenous artery and vein that were precontracted with ergovaline. Blood vessels were collected from mixed breed market rams (n = 7) at slaughter, cleaned of surrounding adipose and connective tissue, sliced into 2-mm cross-sections, and mounted in a multimyograph. Artery and vein cross-sections were equilibrated to 1 g tension in continuously gassed (95% O2/5% CO2) Krebs-Henseleit buffer (pH 7.4; 37.5 °C) for 90 min, precontracted with 1.0 μM ergovaline (in a tall fescue seed extract) for 30 min, exposed to increasing concentrations of 5-HT that ranged from 1 x 10-9 to 1 x 10-4 M for a 5-min interval. Response data were normalized to the 1.0 μM ergovaline response and were analyzed as a completely randomized design in SAS. The saphenous vein was larger in diameter blood vessel than the saphenous artery. Both vessel types contracted in response to exposure to 1 μM ergovaline. The saphenous artery had a much lower maximal response to ergovaline than did the vein (P < 0.05) that could be attributed to the size difference. The lateral saphenous vein relaxed to increasing concentrations of 5-HT (P < 0.05) with 87 % relaxation occurring by 1 x 10-6 M 5-HT. Conversely, the lateral saphenous artery contracted in response to increasing concentrations of 5-HT (P < 0.05) resulting in a 43% increase from the ergovaline response by the 1 x 10-4 M addition. This response did not become significant in the artery until 1 x 10-5 M 5-HT compared with 1 x 10-8 M for the vein. This resulted in a 50% effective concentration for 5-HT in the artery of 4.5 compared with 8.1 M for the vein (P < 0.05). The differing responses across vessels are likely a result of different receptor populations and this should be verified in future research. This is the first reported observation of stimulated relaxation of a blood vessel constricted ergovaline. Additional research is needed to understand the mechanism of how 5HT can be used to stimulate vasorelaxation in livestock suffering from ergot alkaloid-induced vasoconstriction. [ABSTRACT FROM AUTHOR]

Toxic tall fescue contains ergot alkaloids, which induce vasoconstriction in livestock, leading to fescue toxicosis. This condition can impact muscle development due to altered blood flow. Supplementation with 5-HTP may counteract the vasoconstrictive effects of fescue alkaloids. We aimed to investigate the influence of 5-HTP supplementation on satellite cells, myoblast, and preadipocyte numbers in maternal and fetal muscle during late gestation in Suffolk ewes. We hypothesized that 5-HTP supplementation would mitigate the effects of fescue toxicosis on muscle cell populations, potentially promoting muscle development and regeneration in maternal and fetal tissues. Suffolk ewes (n = 75), naïve to toxic tall fescue, were blocked by body condition score and body weight into 10 groups for synchronization. Ewes were confirmed pregnant using transabdominal ultrasound, and lamb number was estimated at gestational day (gd) 60. Pregnant ewes carrying twins (n = 30) were randomly assigned to one of three treatments: 1) negative control (CON, n = 10), 2) toxic tall fescue seed containing 1.77 mg ewe-1ּ d-1 ergovaline/ergovalinine plus 5-HTP (2.5 mg/kg BW) supplement (5HTP, n = 10), or 3) positive control, fed toxic tall fescue seed containing 1.77 mg ewe-1ּ d-1 ergovaline/ergovalinine (E+, n = 10). Ewes were individually fed a total mixed ration from gd 78 to gd 85 of pregnancy and then TMR plus treatment (CON, E+ or 5HTP) from gd 86 to d 111. On gd 112, terminal necropsies were performed, and semimembranosus muscle (SM) from the ewe and fetus was removed. Weights were obtained, and then samples were digested using pronase (1.5mg/mL) to isolate preadipocyte (PP1), myoblasts (PP2) and satellite cell (PP3) fractions using a pre-plating technique. Cells were quantified using a Neubauer-hemocytometer and trypan blue to also assess cell viability and changes in cell number. Fetal SM had a greater (P < 0.05) number of pre-adipocytes, myoblasts, and satellite cells per gram of tissue digested in comparison with the ewes. Pre-adipocyte and myoblast number per gram of tissue digested did not differ (P > 0.05) by treatment. The 5HTP group had the greater (P < 0.05) number of satellite cells per gram of tissue digested in comparison with the CON group. Satellite cell numbers tended (P < 0.10) to be greater in the 5HTP group in comparison to the E+ group. Satellite cell numbers from CON and E+ treatment groups did not differ (P > 0.05). In conclusion, 5-HTP supplementation during late gestation in Suffolk ewes exposed to toxic tall fescue significantly increased satellite cell numbers in maternal and fetal muscle tissues. This suggests a potential mitigation of the impact of fescue toxicosis on muscle cell populations. [ABSTRACT FROM AUTHOR]

The deposition of fat in ruminants is a dynamic process that significantly impacts meat quality and production efficiency. The objective of this study was to investigate the dynamics of fat deposition over time across various depots in bottle-fed ram lambs, focusing on pre-adipocyte cell number and gene expression as a key determinants of fat accumulation. Suffolk ram lambs (n = 13) were serially harvested on d 15 (n = 4), d 45 (n = 4), and d 105 of age (n = 5). Lambs were supplemented with milk replacer 20% of body weight (BW)] from d 5 to d 30 of age, milk replacer (10% BW) with creep feed (2.5% of BW) supplementation from d 30 to 45, and creep feed (5% of BW) from d 45 to d 105 of age. At each harvest timepoint, fat depots, including subcutaneous, intramuscular (longissimus muscle), and visceral fat, were snap-frozen for RNA extraction, downstream gene expression analysis, and fatty acid extraction. Pre-adipocyte cells were also preserved, enzymatically digested and subsequently isolated from each depot. Pre-adipocyte cell number was assessed using the CellDrop (Denovix). Preliminary results revealed that pre-adipocyte cell numbers were significantly greater (P < 0.05) in subcutaneous and visceral depots 17-d old lambs in comparison to all other depots in other timepoints. The number of pre-adipocytes in intramuscular adipose depots did not differ over time (P > 0.05). Visceral and subcutaneous adipose depots had a significantly greater (P < 0.05) amount of preadipocytes present in comparison with the intramuscular depot. Total fatty acid content differed (P < 0.05) among depots and timepoints. Omental fat from d 105 lambs exhibited the greatest (P < 0.05) total fatty acid content in comparison with all other depots. Total fatty acid amount did not statistically differ (P > 0.05) between d 17 and d 45 omental fat depots. Total fatty acid content did not differ (P > 0.05) over time in intramuscular fat samples (LM). The gene expression of several proposed pre-adipogenic markers were evaluated across timepoints and tissues. Moreover, the relationship between pre-adipocyte cell number and fat deposition in both subcutaneous and visceral depots indicates their crucial role in overall fat accumulation in ram lambs. These findings offer novel insights into the dynamics of fat deposition in ruminants, emphasizing the importance of intramuscular fat depots as key sites for fat accumulation. Understanding the relationship between pre-adipocyte cell number and fat deposition across depots can inform management strategies aimed at enhancing meat quality and production efficiency in sheep farming systems. Further research is needed to elucidate the molecular mechanisms underlying fat deposition in different depots and its impact on meat quality traits. [ABSTRACT FROM AUTHOR]

Gestating ewes consuming ergot alkaloids, from endophyte-infected (E+) tall fescue seed, suffer from intrauterine growth restriction and produce smaller lambs. Arginine (Arg) supplementation has been shown to increase birth weight and oral citrulline (Cit) administration is reported to increase arginine concentrations. Two experiments were conducted to: 1) evaluate if oral supplementation with Cit or water, to ewes consuming E+ fescue seed, increases lamb birth weight and 2) determine the effectiveness of Cit and citrulline:malate as an oral drench and elevating circulating levels of Cit to determine levels and dose frequency. In experiment 1, gestating Suffolk ewes (n = 10) were assigned to one of two treatments [oral drench of citrulline–malate 2:1 (CITM; 81 mg/kg/d of citrulline) or water (TOX)] to start on d 86 of gestation and continued until parturition. Ewes on CITM treatment had decreased (P < 0.05) plasma Arg and Cit concentrations during gestation. At birth, lambs from CITM ewes had reduced (P < 0.05) crude fat and total fat but did not differ (P > 0.05) in birth weight from lambs born to TOX ewes. In experiment 2, nonpregnant Suffolk ewes (n = 3) were assigned to either oral citrulline (CIT; 81 mg/kg/d), citrulline–malate 2:1 (CITM; 81 mg/kg/d of citrulline), or water (CON) drench in a Latin Square design for a treatment period of 4 d with a washout period of 3 d. On d 4, blood samples were collected at 0, 0.5, 1, 2, 3, 4, 6, 8, 10, 12, and 18 h post drench. Oral drenching of CIT and CITM increased (P < 0.0001) Cit concentrations within 2 h and levels remained elevated for 6 h. Apparent half-life of elimination for CIT and CITM were 8.484 and 10.392 h, respectively. Our results show that lamb birth weight was not altered with a single oral drench of citrulline–malate; however, lamb body composition was altered. The level and frequency of citrulline dosing may need to be greater in order to observe consistent elevation of Cit/Arg concentrations to determine its effectiveness in mitigating fescue toxicosis. [ABSTRACT FROM AUTHOR]

Herbivores that consume ergot alkaloids frequently suffer from vasoconstriction that can result in a myriad of symptoms that can range from necrosis of peripheral tissues to fetal intra-uterine growth restriction. As part of a larger study screening compounds that may mitigate the vasoconstrictive effects of ergot alkaloids, the objective of this experiment was to evaluate serotonin (5-HT) as vasorelaxant in the ovine saphenous artery and vein. Blood vessels were collected from a total mixed breed market rams (n = 16; approximate BW = 58 kg) at slaughter, cleaned of surrounding adipose and connective tissue, sliced into 2-mm crosssections, and mounted in a multimyograph. Artery and vein cross-sections were equilibrated to 1 g tension in continuously gassed (95% O2/5% CO2) Krebs-Henseleit buffer (pH 7.4; 37.5 °C) for 90 min, precontracted with 0.0001 M phenylephrine for 15 min, exposed to concentrations of 5-HT that ranged from 1 x 10-9 to 1 x 10-4 M for a 5-min interval. Response data were normalized to the 0.0001 M phenylephrine response and were analyzed as a completely randomized design in SAS. The lateral saphenous vein (n = 5 lambs) relaxed to increasing concentrations of 5-HT (P < 0.05) with 65 to 75 % relaxation occurring at 1 x 10-7 M through 1 x 10-4 5-HT. Conversely, the lateral saphenous artery (n = 6 lambs) contracted in response to increasing concentrations of 5-HT (P < 0.05) resulting in a 255% increase from the phenylephrine response by the 1 x 10-4 M addition. In a subsequent experiment, saphenous veins from the remaining lambs (n = 5) were treated the same, but in place of increasing concentrations of 5-HT, saphenous veins were exposed to increasing concentrations of selective 5-HT receptor agonists to determine the receptor subtypes involved in the previously observed vasorelaxation. Agonists for receptors 5-HT2B (BW 723C86; a-methyl-5-(2-thienylmethoxy)-1H-indole-3-ethanamine hydrochloride), 5-HT4 (BIMU-8; 2,3-Dihydro-N-[(3-endo)-8-methyl-8-azabicyclo[3.2.1]oct-3-yl]-3-(1-methylethyl)-2-oxo-1Hbenzimidazole-1-carboxamide hydrochloride), and 5-HT7 (LP44; 4-[2-(methylthio)phenyl]-N-(1,2,3,4-tetrahydro-1-naphthalenyl)-1-piperazinehexanamide, monohydrochloride) were used. These 5-HT receptor subtypes were selected based on their association with vascular smooth muscle relaxation. While all three 5-HT receptor subtypes resulted in vasorelaxation (P < 0.05), the 5-HT2B agonist only stimulated a maximal relaxation of 32% compared with the agonists for 5-HT4 and 5-HT7 that resulted in maximal relaxation of 68% and 50%, respectively. The agonist for 5-HT4 produced the greatest relaxation in the ovine lateral saphenous vein and should be targeted in subsequent research. It is likely that the combined effect of binding multiple receptor subtypes contributes to the overall effect of 5-HT. The focus on development of ergot alkaloid mitigation strategies should consider the divergent responses of arteries and veins to serotonin in peripheral tissues. [ABSTRACT FROM AUTHOR]

In the cattle industry, fat deposited on a carcass can have advantages and disadvantages depending on location and amount. Excess subcutaneous fat deposition reduces carcass red meat yield, while intramuscular fat (IMF) deposition, or marbling, increases carcass value and enhances tenderness and flavor. Two distinct adipocyte growth cycles can be attributed to total fat deposition: hypertrophy and hyperplasia. Hyperplasia refers to the adipogenic side of growth where there is an increase in preadipocyte cell number before cell differentiation. This study aimed to investigate the effects of altering fatty acid composition of cell culture media in vitro on preadipocyte hyperplasia. Subcutaneous fat was harvested from Angus-cross yearling steers (n = 4). Subcutaneous preadipocytes were isolated and propagated for a series of six passages. Preadipocytes were subsequently seeded, and eight different treatment mixtures with combinations of different fatty acids (C16:0, C18:0, C18:1cis-9, and C18:2cis-9,12) at varying ratios were added to the basal media (DMEM F12, 10% bovine fetal serum, 1% HEPES, 1% AB/AM) for a period of four days. Cell culture treatment media was changed daily. Each individual media mix was applied at the same total molar concentration (200 ug). At the end of the fourday treatment period, cells were harvested for RNA extraction and fatty acid analysis. The expression of critical adipogenic and lipogenic genes was evaluated. Treatments displayed differences (P < 0.05) in total fatty acid content (ug), which would suggest that the addition of fatty acids to media could push primary bovine preadipocytes into differentiation. Mix 8 (75% 18:1cis-9 - 25% 18:2cis-9,12) exhibited the greatest (P < 0.05) fatty acid content (ug), while mix 5 (50% C16:0-50% C18:0) had the least (P < 0.05) fatty acid amount (ug). The expression of fatty acid binding protein-4 (FABP4) and stearoyl Co-A desaturase-1 (SCD-1) differed (P < 0.05) across treatments. The expression of peroxisome proliferating-activated receptor gamma (PPARy), sterol-regulatory element-binding protein (SREB-1c), and SREBP cleavage-activating protein (SCAP) were all downregulated (P < 0.05) in the fully saturated fatty acid mix, mix 5 (50% C16:0-50% C18:0), compared with all other treatments. Based on the data, it appears that the addition of fatty acids at different ratios to media can affect molecular mechanisms, hyperplastic growth, and potentially the differentiation of primary bovine adipocytes. Additional examination of fatty acid supplementation in vitro could provide valuable insight into their effects on adipocyte growth and how it could be applied to alter fat deposition in vivo. [ABSTRACT FROM AUTHOR]

microRNAs (miRNA) are present in skeletal muscle and play important roles in regulating gene expression. Previous research identified miR-22-3p and miR-127 as differentially regulated during muscle hypertrophy and in vitro experiments found that antagomir-22-3p and mimic-127 enhanced satellite cell proliferation. The objective of this study was to test in vivo intramuscular injection of agomiR-127 or antagomir-22-3p in the longissimus muscle (LM) on miRNA and target mRNA expression in intrauterine growth restricted lambs. Pregnant ewes (n = 18) with twins were nutrient restricted (60%) from gestational d 85 to parturition. On d 2 of age, lambs were randomly selected and assigned to one of two miRNA treatments, 1) agomiR-127 (AGO127, 100 nM, n = 9) to assess gain of function or 2) antagomiR-22-3p (ANT22, 500 nM, n = 9) to assess loss of function. AgomiR and antagomiR technologies are chemically modified miRNA mimics or inhibitors that do not require transfection for in vivo use. AgomiR-127 or antagomir-22-3p were reconstituted in phosphate buffered saline (PBS) and injected into the center of the LM on the left side every 3-d starting at the 10th rib and moving posterior by 1.27 cm at each injection for a total of 7 injections. A sham control treatment (SHAM127 or SHAM22) of PBS was administered following the same protocol in the right LM to serve as the in-animal control. Lambs were harvested 4 d after the last injection and samples were collected from the injection region of each LM for miRNA and mRNA expression, histology, and proteomic analyses. Data were analyzed using paired t-tests to compare each miRNA treatment to its SHAM within animal. AGO127 up-regulated (P = 0.0071) miR-127 expression compared with SHAM127. mRNA expression of PAX7 and MSTN were up-regulated (P < 0.05) and IGFBP2 expression was down-regulated (P < 0.05) for AGO127 compared with SHAM127. Both protein and DNA content of AGO127 were increased (P < 0.05) but the ratio of protein to DNA did not change (P > 0.05). Proteomic analyses found 11 proteins that were differentially expressed for AGO127 compared with SHAM127. ANT22 down-regulated (P = 0.0024) miR-22-3p expression from SHAM22. Expression of predicted mRNA targets of miR-22-3p (ACVR2a, ACVR2b, SIRT1), myosin heavy chain isoforms (MyHCI, MyHCIIa, MyHCIIx), and other myogenic genes (MAPK6, IGF1, MyoG) were also altered (P < 0.05) in the LM compared with SHAM22. DNA content and the protein to DNA ratio was greater (P < 0.05) in ANT22 than SHAM22. Proteomic analyses identified nine proteins that were differentially expressed (P < 0.05) for ANT22. The direct injection of agomiR and antagomir technologies in the LM up- and downregulated expression, respectively, for the miRNA of interest, which altered mRNA expression of predicted targets, protein abundance and muscle fiber type. [ABSTRACT FROM AUTHOR]

Wagyu cattle are known to deposit greater amounts of intramuscular fat, which can directly increase quality grade and carcass value. Supplementation can positively influence animal production and overall nutrient acquisition when used strategically. The objectives of this study were to evaluate 1) the effect of breed and early supplementation on intramuscular and subcutaneous fat deposition in Wagyu and Hereford cross calves, and 2) changes in adipogenic and lipogenic gene expression in longissimus muscle (LM) biopsies from Wagyu and Hereford cross calves during an early supplementation period. Angus cows (n = 34) were artificially inseminated with semen from a Wagyu bull. A Hereford bull was utilized as a clean-up bull. From this breeding, Wagyu cross steers (n = 8) and Hereford cross steers (n = 9) were produced and were placed on study on day 100 of age. At this time, calves were allowed access to four SuperSmart Feeder stalls and were individually supplemented with steam-rolled corn at 0.5% body weight (BWT). Calves were ultrasounded on day 0, day 43, and day 86 of the study to evaluate intramuscular fat deposition and backfat thickness. An longissimus muscle (LM) biopsy was taken on day 0 and day 86 of the study to evaluate gene expression. Supplemented steers tended (P < 0.10) to have more backfat than non-supplemented steers. Intramuscular fat amount differed (P < 0.05) by breed, while ribeye area tended (P < 0.10) to differ by breed. Wagyu exhibited a greater (P < 0.05) amount of intramuscular fat at the beginning and at the end of the study. Breed did not (P > 0.05) influence backfat thickness. Neither breed nor supplementation affected (P > 0.05) average daily gain or final body weights. Platelet-derived growth factor alpha (PDGRFA) and SREBP cleavage-activating protein (SCAP) differed (P < 0.05) between biopsy phases. Fatty acid binding protein-4 (FABP4) and stearoyl-coA desaturase-1 (SCD1) did not differ (P > 0.05) between breed or biopsy phase. In conclusion, changes in gene expression could indicate enhanced preadipocyte proliferation during this stage of calf development. Overall, supplementation altered backfat deposition but did not alter intramuscular fat levels. Opposingly, sire breed influenced intramuscular fat levels at an early age. A deeper understanding of the physical and molecular effects of supplementation and sire breed could provide additional avenues for manipulating adipose tissue. [ABSTRACT FROM AUTHOR]

The objective of this study was to assess how exposure to ergot alkaloids during 2 stages of gestation alters fetal growth, muscle fiber formation, and miRNA expression. Pregnant ewes (n = 36; BW = 83.26 ± 8.14 kg; 4/group; 9 groups) were used in a 2 × 2 factorial arrangement with 2 tall fescue seed treatments [endophyte-infected (E+) vs. endophyte-free (E−)] fed during 2 stages of gestation (MID, days 35 to 85 vs. LATE, days 86 to 133), which created 4 possible treatments (E−/E−, E+/E−, E−/E+, or E+/E+). Ewes were individually fed a total mixed ration containing E+ or E− fescue seed according to treatment assignment. Terminal surgeries were conducted on day 133 of gestation for the collection of fetal measurements and muscle samples. Data were analyzed as a 2 × 2 factorial with fescue treatment, stage of gestation, and 2-way interaction as fixed effects. Fetuses exposed to E+ seed during LATE gestation had reduced (P = 0.0020) fetal BW by 10% compared with E− fetuses; however, fetal body weight did not differ (P = 0.41) with E+ exposure during MID gestation. Fetuses from ewes fed E+ seed during MID and LATE gestation tended to have smaller (P = 0.058) kidney weights compared with E− fetuses. Liver weight was larger (P = 0.0069) in fetuses fed E− during LATE gestation compared with E+. Fetal brain weight did not differ by fescue treatment fed during MID (P = 0.36) or LATE (P = 0.40) gestation. The percentage of brain to empty body weight (EBW) was greater (P = 0.0048) in fetuses from ewes fed E+ fescue seed during LATE gestation, which is indicative of intrauterine growth restriction (IUGR). Primary muscle fiber number was lower (P = 0.0005) in semitendinosus (STN) of fetuses exposed to E+ during MID and/or LATE gestation compared with E−/E−. miRNA sequencing showed differential expression (P < 0.010) of 6 novel miRNAs including bta-miR-652_R+1, mdo-miR-22-3p, bta-miR-1277_R-1, ppy-miR-133a_L+1_1ss5TG, hsa-miR-129-1-3p, and ssc-miR-615 in fetal STN muscle. These miRNA are associated with glucose transport, insulin signaling, intracellular ATP, hypertension, or adipogenesis. This work supports the hypothesis that E+ tall fescue seed fed during late gestation reduces fetal weight and causes asymmetrical growth, which is indicative of IUGR. Changes in primary fiber number and miRNA of STN indicate that exposure to E+ fescue fed during MID and LATE gestation alters fetal muscle development that may affect postnatal muscle growth and meat quality. [ABSTRACT FROM AUTHOR]

The objective of this study was to examine the effects of flaxseed (FLAX) oil or 16‐carbon n‐7 fatty acid ‐enhanced fish oil (Provinal; POA) supplementation on serum, liver and skeletal muscle fatty acid concentrations, serum ceramide and plasma insulin concentrations, and gene expression. Lambs [n = 18; 42 ± 5.6 kg body weight (BW); 7 months] were individually fed one of the three treatments: (1) control (CON), no oil supplement, (2) FLAX; at 0.1% of BW, or (3) POA at 0.1% of BW for 60 days. Daily feed intake and weight gain were decreased by 21% and 34%, respectively, for POA than FLAX. Liver and skeletal muscle concentrations of palmitoleic acid were greater by 396% and 87%, respectively, for POA than FLAX; whereas, liver and skeletal muscle α‐linolenic acid concentrations were greater by 199% and 118%, respectively, for FLAX. Supplementation with POA also had greater serum and tissue concentrations of eicosapentaenoic and docosahexaenoic acids. Serum glucose and plasma insulin concentrations were elevated with FLAX supplementation at the end of the study. Supplementation with POA altered serum ceramide concentrations compared to CON or FLAX. Oil supplementation, both FLAX and POA, downregulated expression of unesterified fatty acid receptors (FFAR) 1 and FFAR4 in the liver; however, oil supplementation upregulated expression of FFAR1 in muscle. Interleukin‐6 (IL6) and tumor necrosis factor‐α (TNFA) expression were downregulated with oil supplementation in the liver; however, FLAX upregulated TNFA in muscle. These results show that oil supplementation can enhance uptake and deposition of unique fatty acids that alter ceramide concentrations and gene expression in tissues. [ABSTRACT FROM AUTHOR]

Previous research has shown that livestock exposed to ergot alkaloids results in decreased vasoactivity of gastrointestinal and peripheral vasculature. Little is known regarding the effect ergot alkaloid exposure during gestation may have on vasculature supporting the fetus. The objective of this study was to evaluate contractile responses of uterine and umbilical arteries collected from ewes consuming ergot alkaloids during gestation. On day 35 of gestation, 36 Suffolk ewes (78.24 ± 9.5 kg) were assigned to endophyte-infected (E+) or endophyte-free (E−) tall fescue seed treatments that were fed either throughout or switched on day 86 of gestation, creating four seed treatments E+E+, E+E−, E−E+, and E−E−. Ewes were fed E+ tall fescue seed to provide 1.77 mg of total ergovaline ⋅ hd−1 ⋅ d−1 with E− ewes receiving the same quantity of E− seed. Gestation was terminated on day 133, and sections of uterine artery and umbilical cord were surgically collected. Only collections from 28 ewes (n = 7/treatment) were of sufficient viability to proceed with the contractility experiments. Arteries were cleaned, sliced into 2-mm cross sections, and suspended in multi-myograph chambers containing 5 mL of continuously oxygenated Krebs–Henseleit buffer. Vessels were exposed to increasing concentrations (5 × 10−8 to 1 × 10−4 M) of norepinephrine, serotonin, ergotamine, and ergovaline (5 × 10−9 to 1 × 10−5 M ; extract of tall fescue seed) in 15-min intervals. Increasing concentrations of norepinephrine generated a contractile response by the uterine artery (P < 0.05), but no response in the umbilical artery. Increasing concentrations of serotonin resulted in negligible responses in uterine preparations, whereas umbilical artery preparations were responsive (P < 0.05) to serotonin. Ewes receiving E+E+ and E−E+ treatments had decreased vasoactivity in umbilical arteries to serotonin with a dextral shift in concentrations where the response curve initiated (P < 0.05). Interestingly, uterine arteries were not responsive to exposure to ergotamine or ergovaline, whereas umbilical arteries were responsive (P < 0.05). Umbilical arteries collected from ewes receiving E−E− and E+E− were more vasoactive to ergot alkaloids (P < 0.05) than other treatments. These findings indicate that maternal blood supply to the placenta appears protected from negative effects of ergot alkaloids; however, umbilical vasculature is not, and this could adversely influence fetal growth. [ABSTRACT FROM AUTHOR]

Tall fescue [ Lolium arundinaceum (Scheyreb.) Darbysh] is the primary cool season forage grass in the Southeastern United States. Most tall fescue contains an endophytic fungus (Epichloë coenophiala) that produces ergot alkaloids and upon ingestion induces fescue toxicosis. The objective of this study was to assess how exposure to endophyte-infected (E+ ; 1.77 mg hd−1 d−1 ergovaline and ergovalinine) or endophyte-free (E- ; 0 mg hd−1 d−1 ergovaline and ergovalinine) tall fescue seed fed during 2 stages of gestation (MID, days 35–85/ LATE, days 86–133) alters placental development. Thirty-six, fescue naïve Suffolk ewes were randomly assigned to 1 of 4 fescue treatments: E−/E−, E−/E+, E+/E−, or E+/E+. Ewes were individually fed the same amount of E+ or E− seed mixed into total mixed ration during MID and LATE gestation. Terminal surgeries were conducted on day 133 of gestation. Ewes fed E+ fescue seed had elevated (P < 0.001) ergot alkaloid excretion and reduced (P < 0.001) prolactin levels during the periods when fed E+ seed. Ewes switched on day 86 from E− to E+ seed had a 4% reduction (P = 0.005) in DMI during LATE gestation, which translated to a 2% reduction (P = 0.07) in DMI overall. Average daily gain was also reduced (P = 0.049) by 64% for E−/E+ ewes during LATE gestation and tended to be reduced (P = 0.06) by 33% overall. Ewes fed E+ seed during LATE gestation exhibited a 14% and 23% reduction in uterine (P = 0.03) and placentome (P = 0.004) weights, respectively. Caruncle weights were also reduced by 28% (P = 0.003) for E−/E+ ewes compared with E−/E− and E+/E−. Ewes fed E+ seed during both MID and LATE gestation exhibited a 32% reduction in cotyledon (P = 0.01) weights, whereas ewes fed E+ seed only during MID gestation (E+/E−) had improved (P = 0.01) cotyledon weights. The percentage of type A placentomes tended to be greater (P = 0.08) for E+/E+ ewes compared with other treatments. Other placentome types (B, C, or D) did not differ (P > 0.05). Total fetal weight per ewe was reduced (P = 0.01) for ewes fed E+ seed during LATE gestation compared with E−; however, feeding E+ seed during MID gestation did not alter (P = 0.70) total fetal weight per ewe. These results suggest that exposure to ergot alkaloids during LATE (days 86–133) gestation has the greatest impact on placental development by reducing uterine and placentome weights. This, in turn, reduced total fetal weight per ewe by 15% in ewes fed E+ seed during LATE gestation (E−/E+ and E+/E+). [ABSTRACT FROM AUTHOR]

Mentored undergraduate research experiences have been identified as beneficial to students for persistence in STEM disciplines and increased grade point averages. Participation in research is impactful for both STEM and non-STEM students. Additionally, undergraduate research experiences have a positive effect on subsequent student performance in graduate and professional school as evidenced by students with previous research experience having superior communication skills at the start of their first year and after. Undergraduate research courses tend to be heavily hands-on experiences and structured classroom teaching may not be large portions of the course content. Online material has become increasingly common in the post COVID-19 learning environment. Courses that can have difficulty with online instruction or the inclusion of online content tend to be courses with a heavy focus of hands-on learning or hands-on skill development. The use of a flipped classroom can facilitate student learning in a digital way in addition to in person class meeting. The incorporation of online lecture content to broaden undergraduate student understanding of the application of the scientific method was used to enhance the research experience. Student experiences were evaluated with the Undergraduate Research Student Self-Assessment survey. Significant positive correlation was found between student feelings of "project responsibility" and "Workshops on science writing and presentation" during the semester that online lectures were incorporated. Additionally, graduate student training is a variable and highly individualized experience for each trainee. Most programs focus strongly on cognitive skill training, advanced knowledge of the discipline, conducting research, and preparing manuscripts for publication. Professional development is a component of graduate training that can be easily overlooked or undervalued. The development of soft skills such as time management, personnel management, and leadership and mentoring qualities are vital for trainee success post-graduation. Some current thinking is that devoting time to professional development will result in a slower progression by the trainee, however this is shown to be untrue and students who participate in career growth maintained the same level of productivity measured by time to degree completion and manuscript output. Graduate student experiences with mentoring undergraduates were shown to develop soft skills while also being noted as "an influential experience" when making future career decisions. Development of an undergraduate research program that incorporates more than simply hands on skill development that also significantly incorporates graduate students benefits both student groups and leads to improved outcomes for both student groups post-graduation. [ABSTRACT FROM AUTHOR]

The Texel breed is a double muscled breed of sheep that is commonly used as a terminal sire in meatproduction. The increase in muscle mass is related to a single nucleotide polymorphism in the myostatin gene, a myokine that inhibits muscle growth. There is limited information on how postnatal skeletal muscle fiber hypertrophy is altered in Texel lambs. Satellite cells or muscle stem cells have a major role in postnatal hypertrophy of muscle fibers. Satellite cells are generally found in a state of quiescence and must activate, proliferate, and differentiate to increase DNA content in myofibers during periods of postnatal muscle growth. The objective of this study was to evaluate muscle fiber hypertrophy and satellite cell proliferation and differentiation in lambs of two sire breeds, Texel or Suffolk. Male lambs of each sire breed (n = 4/sire breed/time) were harvested at d 2, 14, and 203 of age. Muscle samples were collected from the longissimus and snap frozen for examination of myofiber cross-sectional area by fluorescent immunohistochemistry. Another portion of the longissimus was used to isolate satellite cells for in vitro experiments to examine population number, proliferation, and differentiation capacity. Isolated satellite cells were counted, seeded for activation, and grown until colonies reached 80% confluence. Activated cells were seeded for a proliferation assay measuring DNA content daily for 6 days. Following proliferation, cells were differentiated for 4 days, and the number of differentiated nuclei were counted with fluorescent immunohistochemistry. Sire breed did not impact (P < 0.05) the weight of the longissimus; however, muscle ribeye area tended (P < 0.10) to be increased for Texel lambs compared with Suffolk lambs. In the early postnatal period, from d 2 to 14, longissimus mass increased (P < 0.05) by 160%, and ribeye area increased by 100%. Between d 4 and 203 longissimus mass increased (P < 0.05) by 350%, while longissimus area only increased by 100%. Muscle fiber cross sectional area expanded (P < 0.05) from d 14 to 203 of age, and cross-sectional area was greater (P < 0.05) for Texel than Suffolk lambs at d 203. Satellite cell populations per gram of tissue increased (P < 0.05) between d 2 and 14 and decreased from d 14 to 203. The number of satellite cells that activated from quiescence was reduced (P < 0.05) as animal age increased but was not impacted (P > 0.05) by sire breed. Following activation, satellite cell proliferation capacity was greater (P < 0.05) for Texel compared with Suffolk satellite cells. Differentiation capacity was not altered (P > 0.05) by sire breed. Texel-sired lambs had larger longissimus cross-sectional muscle fiber area at d 203 of age than Suffolk. These changes appear to be related to greater proliferation of satellite cells, the stem cells of muscle, to enhance muscle fiber hypertrophy during postnatal growth. [ABSTRACT FROM AUTHOR]

Thirty-six Angus-cross steers (667 ± 34.4 kg initial BW, 24.5 mo) were used to assess the impact of short-term glycerin or high-fructose corn syrup administration via drinking water on meat quality and marbling deposition. Steers blocked by BW (3 blocks) were assigned randomly to 1 of 3 drinking water treatments: 1) control (CON), 2) 4.3% crude glycerin (GLYC), or 3) 4.3% high-fructose corn syrup (HFCS) for the final 25 d before slaughter. Average daily gain was lower (P = 0.01) and final live weight was lower (P < 0.01) with HFCS administration compared with CON. Dry matter intake and water intake did not differ among treatments. Fat thickness, muscle depth, and intramuscular fat measured by ultrasound did not differ among treatments. Crude glycerin or HFCS via water supplementation did not alter HCW, dressing percentage, rib eye area, fat thickness, KPH, skeletal maturity, or marbling score. Longissimus muscle and subcutaneous fat color (L*, a*, and b*) were not affected by drinking water treatment. Total lipid content, total fatty acid content, and fatty acid composition of the LM did not differ among drinking water treatments. Supplementation of drinking water with GLYC or HFCS did not alter Warner-Bratzler shear force values or water-holding capacity (drip loss, cook shrink). Intramuscular mean adipocyte diameter was greater (P = 0.02) for steers offered HFCS compared with steers offered GLYC, with CON steers being intermediate. These differences in mean adipocyte size were related to changes in the adipocyte size distribution. There were greater proportions of small (20 to 30 µm) adipocytes in GLYC compared with HFCS and CON. In contrast, HFCS and CON had greater proportions of medium (40 to 50 µm) adipocytes than GLYC. The relative mRNA expression of lipogenic genes (acetyl Co-A carboxylase [ACC], fatty acid binding protein 4 [FABP4], fatty acid synthase [FASN], glycerol-3-phosphate acyltransferase [GPAT], retinol-binding protein 4 [RBP4], and stearoyl-CoA desaturase [SCD]), adipocyte differentiation genes (delta-like 1 homolog [DLK1]), and transcription factors (CCAAT/enhancer-binding protein α [C/EBPα], and PPARγ) was similar for GLYC and HFCS compared with CON. Longissimus glycogen and lactate concentrations and glycolytic potential were not affected by drinking water treatments. Overall, HFCS or GLYC supplementation via drinking water did not alter carcass or meat quality variables but did alter the size and distribution of intramuscular adipocytes. These results indicate that a longer supplementation time or a higher substrate level may be needed to obtain differences in meat quality. [ABSTRACT FROM AUTHOR]

The objective of this study was to examine how the use of specific miRNA mimics or inhibitors alters ovine satellite cell proliferation in vitro. Satellite cells were isolated from a Texel x Suffolk cross lamb at d 2 of age and cell purity was assessed with PAX7 protein staining and the population was 95% pure. miRNA candidates were selected from miRNA sequencing of the longissimus muscle at several time points from gestational d85 to market weight. Satellite cells were plated and allowed to reach 60% confluence, then treated with a miRNA mimic (miR-127 or 299a) at 50 or 100nM or a miRNA AntagomiR (miR-22-3p, 29a, 133, or 27) at 500nM using lipofectamine transfection reagent. Cells were allowed to proliferate for 4d following transfection and samples were collected daily for proliferation analysis using DNA quantification. Experiments were replicated and data analyzed using a priori contrasts with miRNA treatment in the model. DNA quantification showed that miR-127 mimic-100nM and miR-22-3p AntagomiR increased (P< 0.05) DNA content after 4d of proliferation following transfection. miR-127 mimic-100nM treatment increased (P< 0.05) miR-127 expression relative to controls at d1 and d4 post transfection. miR-22-3p AntagomiR transfection tended (P< 0.10) to reduce miR-22-3p expression on d4 post-transfection. miR-22-3p AntagomiR did not alter (P>0.05) PAX7, MYOD, or MYOG expression compared with the control. miR-127 mimic-100nM treatment did not alter (P>0.05) PAX7 expression, while it did increase (P< 0.05) MYOD expression on d4 and reduced (P< 0.05) MYOG expression compared to the control. mRNA sequencing was performed on d4 samples to determine possible miR-127 and 22-3p targets. IGF1, fibroin and other extra cellular matrix proteins were identified from miR-127 treated samples and CNDP2, involved in carnosine hydrolysis, was identified from miR-22-3p treated samples. miR-127 and 22-3p enhanced satellite cell proliferation and therefore could be used to promote muscle fiber hypertrophy. [ABSTRACT FROM AUTHOR]

Tall fescue [Schedonorus phoenix (Scop.) Holub] accounts for nearly 16 million hectares of pasture in the Southeastern and Mid-Atlantic U.S. due to its heat, drought, and pest resistance, conferred to the plant by its symbiotic relationship with the endophyte Neotyphodium coenophialum. The endophyte produces ergot alkaloids that have negative effects on the growth and reproduction of animals, resulting in the syndrome known as fescue toxicosis. The objectives of our study were to identify microRNA (miRNA) present in bovine sperm and to evaluate the effects of fescue toxicosis on sperm miRNA expression. Angus bulls were assigned to treatments of either toxic or non-toxic fescue seed diets. Semen was collected and subjected to RNA isolation. Three samples from each treatment group were chosen and pooled for deep sequencing. To compare miRNA expression between treatment groups, a microarray was designed and conducted. For each of the top ten expressed miRNA, target prediction analysis was conducted using TargetScan. Gene ontology enrichment was assessed using the Database for Annotation, Visualization and Integrated Discovery. Sequencing results elucidated the presence of 1,582 unique small RNA present in sperm. Of those sequences, 382 were known Bos taurus miRNA, 22 were known but novel to Bos taurus, and 816 were predicted candidate miRNA that did not map to any currently reported miRNA. Of the sequences chosen for microarray, twenty-two showed significant differential expression between treatment groups. Gene pathways of interest included: regulation of transcription, embryonic development (including blastocyst formation), Wnt and Hedgehog signaling, oocyte meiosis, and kinase and phosphatase activity. MicroRNA present in mature sperm appears to not only be left over from spermatogenic processes, but may actually serve important regulatory roles in fertilization and early developmental processes. Further, our results indicate the possibility that environmental changes may impact the expression of specific miRNA. [ABSTRACT FROM AUTHOR]

Obese sheep were used to assess the effects of palmitoleic (C16:1 cis-9) acid infusion on lipogenesis and circulating insulin levels. Infusion of 10 mg/kg body weight (BW)/day C16:1 intravenously in obese sheep reduced (P<0.01) weight gain by 77%. Serum palmitoleic levels increased (P<0.05) in a linear manner with increasing levels of C16:1 infusion. Cis-11 vaccenic (C18:1 cis-11) acid, a known elongation product of palmitoleic acid, was also elevated (P<0.05) in serum after 14 days and 21 days of infusion. Plasma insulin levels were lower (P<0.05) (10 mg/ kg BW/day C16:1) than controls (0 mg/kg BW/day C16:1) at 14 days and 28 days of infusion. Infusion of C16:1 resulted in linear increases in tissue concentrations of palmitoleic, cis-11 vaccenic, eicosapentaenoic, and docosapentaenoic acids in a dose-dependent manner. Total lipid content of the semitendinosus (ST) muscle and mesenteric adipose tissue was reduced (P<0.01) in both 5 mg/kg and 10 mg/kg BW C16:1 dose levels. Total lipid content and mean adipocyte size in the longissimus muscle was reduced (P<0.05) in the 10 mg/kg BW C16:1 dose level only, whereas total lipid content and adipocyte size of the subcutaneous adipose tissue was not altered. Total lipid content of the liver was also unchanged with C16:1 infusion. Palmitoleic acid infusion upregulated (P<0.05) acetyl-CoA carboxylase (ACC), fatty acid elongase-6 (ELOVL6), and Protein kinase, AMP-activated, alpha 1 catalytic subunit, transcript variant 1 (AMPK) mRNA expressions in liver, subcutaneous adipose, and ST muscle compared to the controls. However, mRNA expression of glucose transporter type 4 (GLUT4) and carnitine palmitoyltransferase 1b (CPT1B) differed between tissues. In the subcutaneous adipose and liver, C16:1 infusion upregulated (P<0.05) GLUT4 and CPT1B, whereas these genes were downregulated (P<0.05) in ST muscle with C16:1 infusion. These results show that C16:1 infusion for 28 days reduced weight gain, intramuscular adipocyte size and total lipid content, and circulating insulin levels. These changes appear to be mediated through alterations in expression of genes regulating glucose uptake and fatty acid oxidation specifically in the muscles. [ABSTRACT FROM AUTHOR]

The objective was to determine the effect of nutritional milieu of isolated stromal vascular (SV) cells on proliferative capacity of preadipocytes, and adipogenic and lipogenic capacity in adipocytes in vitro. Proliferation of the preadipocytes increased over time with 48 and 72 h being greater than 24 h; however, preadipocytes from steers supplemented with corn (LC) had lower proliferation rates compared with those without corn grain supplementation (L) at 72 h. Adipocyte cultures isolated from LC group had higher mean diameter on d 4 and 6, and higher mean volume on d 0, 4, 6, and 12 of culture. Adipocytes from steers supplemented with corn grain (LC) had lower expression of key adipogenic genes during extended days in culture. The results show that prior nutritional treatment of the donor animal used to isolate SV cultures alters their proliferative, adipogenic, and lipogenic capacity in culture. These differences may be related to lower induction/expression of AP2 gene in the adipose cultures from corn supplemented group. Corn grain supplementation to steers grazing legumes could have stimulated more active adipogenic progenitor cells to differentiate, which would leave fewer behind in the SV pool for subsequent isolation. [ABSTRACT FROM AUTHOR]

Abstract: The aim of this research was to evaluate: 1) fatty acid (FA) profile of eight retail cuts (eye of round, ribeye, top round, striploin, tenderloin, top-sirloin, underblade, ground beef) from grass-fed steers, 2) the association between striploin (longissimus muscle) FA profile and that from the other retail cuts, and 3) the changes in FA profile associated with retail cut total FA content. All of the retail cuts, except underblade and ground beef, would be considered lean (<10g) based on total FA content. Total saturated fatty acids were positively correlated to total FA content; whereas, negative correlations were observed with total FA content and total monounsaturated and polyunsaturated fatty acids. No correlation was observed between total FA and CLA cis-9, trans-11. Striploin trans-11 C18:1 and CLA cis-9, trans-11 proportions, and n-6:n-3 ratio were positive and highly correlated with those in the other retail cuts. [Copyright &y& Elsevier]

Conjugated linoleic acids (CLA) are of important nutritional and health benefit to human. Food products of animal origin are their major dietary source and their concentration increases with high concentrate diets fed to animals. To examine the effects of diet supplementation on the expression of genes related to lipid metabolism, 28 Angus steers were fed either pasture only, pasture with soybean hulls and corn oil, pasture with corn grain, or high concentrate diet. At slaughter, samples of subcutaneous adipose tissue were collected, from which RNA was extracted. Relative abundance of gene expression was measured using Affymetrix GeneChip Bovine Genome array. An ANOVA model nested within gene was used to analyze the background adjusted, normalized average difference of probe-level intensities. To control experiment wise error, a false discovery rate of 0.01 was imposed on all contrasts. Expression of several genes involved in the synthesis of enzymes related to fatty acid metabolism and lipogenesis such as stearoyl-CoA desaturase (SCD), fatty acid synthetase (FASN), lipoprotein lipase (LPL), fatty-acyl elongase (LCE) along with several trancription factors and co- activators involved in lipogenesis were found to be differentially expressed. Confirmatory RT-qPCR was done to validate the microarray results, which showed satisfactory correspondence between the two platforms. Results show that changes in diet by increasing dietary energy intake by supplementing high concentrate diet have effects on the transcription of genes encoding enzymes involved in fat metabolism which in turn has effects on fatty acid content in the carcass tissue as well as carcass quality. Corn supplementation either as oil or grain appeared to significantly alter the expression of genes directly associated with fatty acid synthesis. [ABSTRACT FROM AUTHOR]

In contrast to rodents, adipose tissue serves as the major site of lipogenesis and storage reservoir for excess dietary energy in cattle. Research in rodents shows that adding corn oil (57% C18:2 n-6) to the diet alters lipogenesis enhancing deposition of omega-6 fatty acids. This study examines changes in lipogenic gene expression of subcutaneous adipose tissue from eighteen steers fed increasing levels of dietary corn oil [0 (NONE), 0.31 kg/d (MED) and 0.62 kg/d (HI)] using two platforms, qPCR and microarray. The results show that MED level of oil supplementation up-regulates gene expression of key lipogenic enzymes but that as oil supplementation reaches HI level mRNA encoding lipogenic enzymes responsible for de novo synthesis and desaturation are down-regulated. Changes in specific lipogenic mRNA levels are correlated with changes in tissue fatty acid composition where de novo and desatured fatty acids were reduced with the highest level of oil supplementation. [ABSTRACT FROM AUTHOR]

There is increased competition in the protein market with the entrance of cell-based and plant-based products. Consumers issues with consumption of red meat typically center around saturated (SFA) fatty acid content and environmental impacts associated with production. Nutritional system used for finishing beef and lamb alters fatty acid composition of the meat product. Forages and grasses that are utilized in a grass-fed finishing system increases the animal's intake of a-linolenic acid (C18:3 n-3), the main fatty acid present in plants (57%) that can be converted to eicosapentaenoic (C20:5 n-3), docosapentaenoic (C22:5 n-3) and docosahexaenoic (C22:6 n-3) acids in animal tissues. Grain-fed finishing systems increases the animal's intake of linoleic acid (C18:2 n-6), the main fatty acid present in corn grain (57%), that can be converted to arachidonic acid (C20:4 n-6) and docosatetraenoic acid (C22:4 n-6) in animal tissues. Biohydrogenation of polyunsaturated fatty acids (PUFA) is extensive in the rumen (> 80% of dietary PUFA) and rumen protected supplements are needed to enhance PUFA content of ruminant meat products. Saturated (SFA) and monounsaturated (MUFA) fatty acids are the majority (>75% of total fatty acids) of fatty acids present in ruminant meat products. Therefore, finding approaches to attain greater desaturation of palmitic and stearic acids to their MUFA products, palmitoleic and oleic acids, would be most beneficial. The content of oleic acid and MUFA in beef is highly heritable and some breeds have high levels of MUFA. Stearoyl-CoA desaturase (SCD1) is the rate limiting enzyme in the production of MUFA. More research is needed to find ways of altering SCD1 expression in meat animal tissues to enhance MUFA and lower SFA content. [ABSTRACT FROM AUTHOR]

Lamb production in tropical areas is conducted under heat stress in extensive grazing conditions of naturalized pastures (NP). The average daily gain (ADG) and yields of hot (HCY) and cold (CCY) carcass, wholesale cuts (WSC); neck (N), shoulder (SL), ribs 5-12 (RIB), loin (LN) and leg (LG), and detail cuts (DTC); shoulder chops (SCH), french chops (FCH), ribs (RS), back leg (BL) and shanks (SH) of 12 lambs (X = 19.4 kg) rotationally grazed (3 d occupation and 24 d resting period) for 154 or 238 d were determined. The Lambs grazed >8 h NP, grass hay and water were offered ad libitum, 150 g/d of a supplement (12% CP), and mineral blocks. Weekly weights were used to determine ADG. Lambs were slaughtered at 22 (SW1) or 35 kg (SM2) to determine HCY and CCY, and WSC and DTC yield as % of cold carcass weight. Performance data was analyzed as a randomized experimental (CRD) design over time. Carcass and cut yields data were analyzed as a CRD with 6 replicates per treatment. Lambs fed during 238-d had similar ADG than those fed 154-d (68.14 vs.47.74 g/d). SW1 and SW2 had similar percentages of HCY (35.21 vs. 38.14) and CCY (34.48 vs. 37.40). The WSC as % of cold carcass weight, N (6.43 vs. 7.06), SL (29.95 vs. 30.20), RIB (16.10 vs. 16.95), LN (10.84 vs. 11.33) and LG (36.51 vs. 34.44) were similar for SW1 and SW2. Yield of SCH and SH was lower (P < 0.05) for SW1 (15.80 and 8.11) than SW2 (23.00 and 9.11), but FCH (8.49 vs. 8.57), RS (6.89 vs. 7.00) and BL (36.52 vs 34.45) were similar. In summary, lambs slaughtered at 35 kg improved the retail cut yield, but did not influence ADG, HCY, CCY, and WCY compared to lighter lambs. [ABSTRACT FROM AUTHOR]

The objective of this study was to characterize the miRNA transcriptome of the longissimus muscle during skeletal muscle hypertrophy. Longissimus samples were collected from Suffolk x Texel cross sheep at six developmental time points: Prenatal [gd 85 (PN1), 110 (PN2), and 133 (PN3)] and postnatal [preweaning (d 40; PW1), weaning (d 65; PW2), and maturity (57 kg; MKT)]. Total RNA was extracted for miRNA sequencing. Data were analyzed using a priori comparisons PN1 vs. PN2, PN2 vs. PN3, PN3 vs. PW1, PW1 vs. PW2, PW2 vs. MKT to examine stages of muscle hypertrophy. One hundred forty-two miRNAs were differentially expressed between the 5 comparisons made. The stage from PN3 to PW1 had the most differentially expressed miRNA (115). Examination of the differentially expressed miRNA also showed that 4 miRNA, miR-154a-3p, miR-3956-5p, miR-410-3p, and miR-431, had a log fold change greater than 3 and miR-22-3p had a log fold change greater than 4. Target genes of differentially expressed miRNA were identified and the functional associations of genes were assessed with GOseq. Between all 5 comparisons made, 195 terms were significantly enriched, 86 were from biological process, 42 were from cellular component, and 67 were from molecular function. The miRNA transcriptome of skeletal muscle changes with advancing development and the period from gd133 to d40 appears to have increased transcriptome alteration. [ABSTRACT FROM AUTHOR]

In order to maintain consumer acceptance of lamb meat, producers are aiming to produce leaner lambs through breeding for certain carcass characteristics. The Texel breed is known for its superior muscling phenotype due to a myostatin mutation. Because of this mutation, Texel and Texel cross lambs have been shown to have improved carcass lean with less fat in various locations throughout the carcass. The objective of this study was to observe the impacts of different sire and dam breeds on carcass composition. Lambs (n = 41) were produced by mating two dam breeds (Southdown or Suffolk) and two sire breeds (Southdown or Texel). Lambs were harvested and a hot carcass weight was obtained. At 24 h postmortem, a chilled carcass weight was taken, and each carcass was split in half. The left side of the carcass was cut into the four primal cuts and scanned using a DXA. The right half was used for standard carcass variables. After DXA scans, each primal was weighed and the major muscles were dissected from the primal cuts and weighed. Subsamples of muscles were used for total lipid analysis and Warner-Bratzler Shear Force testing. DXA scans showed a difference in the primal cut mass (P = 0.0207) with the Suffolk-Texel cross having the highest average primal cut mass at 12.52 kg. Southdown-Southdown lambs had the highest fat percentage (dam P = 0.0398; sire P = 0.0116). Dam breed had a more significant effect on muscle toughness (P < 0.0035). Southdown sired lambs had a higher SFA (P = 0.0046) and MUFA (P < .0001) but Texel sired lambs had a higher overall fatty acid ratio (P < .0001). On average, the Suffolk-Texel cross was shown to have heavier average weight for the primal cuts in the rack and leg, which are where some of the more profitable cuts of meat are located. [ABSTRACT FROM AUTHOR]

Grazing endophyte-infected, toxic tall fescue reduces cow/calf production; therefore, this study examines alternate strategies such as use of novel endophyte fescue varieties during late gestation and early lactation or genetic selection of resistant cows. Pregnant cows (n = 75) were randomly assigned to fescue endophyte type: 1) endophyte-infected ergot alkaloid producing tall fescue (E+) or 2) novel endophyte-infected, non-toxic tall fescue (NOV) within maternal (A|A, n = 38 and G|G, n = 37) DRD2 genotype to examine changes in cow/calf performance and milk production during late gestation and early lactation. Grazing E+ fescue pastures during late gestation reduced cow body weight gain but did not alter calf birth weight compared to NOV. Milk production and calf ADG during the first 30 day of lactation were lower for E+ than NOV. The calving rate was reduced, but not calving interval for E+ cows. The adjusted 205-day weight of calves was lower in those grazing E+ with their dams compared to NOV. There were no interactions between DRD2 genotype and fescue endophyte type indicating that genotype was not associated with response to E+ fescue in this study. Overall, grazing NOV tall fescue pastures rather than E+ during critical stages of production improved cow gain during late gestation, calving rate, early milk production and calf growth. [ABSTRACT FROM AUTHOR]

Simple Summary: This study was conducted to examine how ergovaline/ergovalinine ingestion during pregnancy in ewes with different DRD2 genotypes altered ewe and lamb performance. Feeding ergovaline/ergovalinine in last trimester reduced lamb birth weight; however, milk production was lower for all ewes fed ergovaline/ergovalinine. Lambs born to dams fed ergovaline/ergovalinine had slower growth rates and lower weaning weights. These results demonstrate that ingestion of ergot alkaloids during pregnancy can negatively influence lactation, growth of offspring and birth and weaning weights. Recommendations would include strategies to mitigate mycotoxin exposure in pregnant ewes to improve production. Endophyte-infected tall fescue (E+) produces ergovaline and ergovalinine, which are mycotoxins that act as dopamine agonists to suppress prolactin and induce vasoconstriction. The experiment was designed as a 3 × 2 × 2 factorial with DRD2 genotype (AA, AG, GG), fescue seed (endophyte-free, E− or endophyte-infected, E+), stage of gestation (MID, d (day) 35–85; LATE, d 86–parturition) and all interactions in the model. Pregnant Suffolk ewes (n = 60) were stratified by genotype and fed E+ or E− seed in a total mixed ration according to treatment assignment. Serum prolactin concentrations were lower (p < 0.05) in ewes fed E+ seed but did not differ by maternal DRD2 genotype or two-way interaction. Lamb birth weight was lower (p < 0.05) in ewes fed E+ seed in last trimester. Pre-weaning growth rate, milk production and total weaning weight was reduced (p < 0.05) in ewes fed E+ fescue seed during MID and LATE gestation. Ingestion of ergovaline/ergovalinine in last trimester reduces lamb birth weight; however, lamb growth rate, milk production and total weaning weight are reduced in all ewes fed E+ during mid and last trimester. [ABSTRACT FROM AUTHOR]

Simple Summary: Little is known about the exposure to ergot alkaloids, a class of mycotoxins, during fetal development on subsequent post-weaning growth, puberty, and carcass quality of the offspring. This study evaluated post-weaning growth, puberty attainment, and carcass quality in lambs that were exposed to endophyte-infected or endophyte-free tall fescue seed during different stages of gestation. Puberty was delayed in ewe lambs that were exposed to ergot alkaloids during late gestation. Ergot alkaloid exposure had minor effects on growth and carcass traits in wether lambs fed high concentrates but alterations in fat deposition and tenderness were observed. These results indicate that exposure to ergot alkaloids during gestation does alter subsequent post-weaning puberty attainment and body composition of the offspring. Weaned lambs (n = 82), born to ewes fed endophyte-free (E−) or endophyte-infected (E+; 1.77 mg hd−1 d−1 ergovaline + ergovalinine) tall fescue seed from d 35 to 85 of gestation (MID) and/or d 86 of gestation to parturition (LATE), were used to examine how ergot alkaloid exposure during fetal development altered subsequent puberty attainment or carcass quality. Lambs were weaned at 75 d of age and separated by sex to assess puberty in ewe lambs (n = 39) and to evaluate growth, carcass and meat quality in wethers (n = 43). Data were analyzed with maternal fescue treatment, stage of gestation, and two-way interaction in the model. Age at puberty tended (P = 0.06) to be longer for ewe lambs born to dams fed E+ fescue during LATE gestation versus those fed E−. Post-weaning average daily gain tended to be higher (P = 0.07) for wether lambs born to dams fed E+ fescue seed during MID gestation compared to E−. Exposure to ergot alkaloids during fetal growth altered (P < 0.10) longissimus muscle weight and color, lipid deposition, fatty acid composition, and shear force values of semimembranosus muscle in wether lambs. These results indicate that exposure to ergot alkaloids in utero does alter subsequent post-weaning puberty attainment and body composition in offspring. [ABSTRACT FROM AUTHOR]

Previous research has shown that livestock exposed to ergot alkaloids results in decreased vasoactivity of gastrointestinal and peripheral vasculature. Little is known regarding the effect ergot alkaloid exposure during gestation may have on vasculature supporting the fetus. The objective of this study was to evaluate contractile responses of uterine and umbilical arteries collected from ewes consuming ergot alkaloids during gestation. On day 35 of gestation, 36 Suffolk ewes (78.24 ± 9.5 kg) were assigned to endophyte-infected (E+) or endophyte-free (E−) tall fescue seed treatments that were fed either throughout or switched on day 86 of gestation, creating four seed treatments E+E+, E+E−, E−E+, and E−E−. Ewes were fed E+ tall fescue seed to provide 1.77 mg of total ergovaline ⋅ hd−1 ⋅ d−1 with E− ewes receiving the same quantity of E− seed. Gestation was terminated on day 133, and sections of uterine artery and umbilical cord were surgically collected. Only collections from 28 ewes (n = 7/treatment) were of sufficient viability to proceed with the contractility experiments. Arteries were cleaned, sliced into 2-mm cross sections, and suspended in multi-myograph chambers containing 5 mL of continuously oxygenated Krebs–Henseleit buffer. Vessels were exposed to increasing concentrations (5 × 10−8 to 1 × 10−4 M) of norepinephrine, serotonin, ergotamine, and ergovaline (5 × 10−9 to 1 × 10−5 M ; extract of tall fescue seed) in 15-min intervals. Increasing concentrations of norepinephrine generated a contractile response by the uterine artery (P < 0.05), but no response in the umbilical artery. Increasing concentrations of serotonin resulted in negligible responses in uterine preparations, whereas umbilical artery preparations were responsive (P < 0.05) to serotonin. Ewes receiving E+E+ and E−E+ treatments had decreased vasoactivity in umbilical arteries to serotonin with a dextral shift in concentrations where the response curve initiated (P < 0.05). Interestingly, uterine arteries were not responsive to exposure to ergotamine or ergovaline, whereas umbilical arteries were responsive (P < 0.05). Umbilical arteries collected from ewes receiving E−E− and E+E− were more vasoactive to ergot alkaloids (P < 0.05) than other treatments. These findings indicate that maternal blood supply to the placenta appears protected from negative effects of ergot alkaloids; however, umbilical vasculature is not, and this could adversely influence fetal growth. [ABSTRACT FROM AUTHOR]