Maternal protein supplementation during mid-gestation improves offspring performance and metabolism in beef cows

This study examined the impact of maternal protein supplementation during mid-gestation on offspring, considering potential sex-related effects. Forty-three pregnant purebred Tabapuã beef cows (20 female and 23 male fetuses) were collectively managed in a pasture until 100 d of gestation. From 100 to 200 d of gestation, they were randomly assigned to the restricted group [(RES) - basal diet (75% corn silage + 25% sugar cane bagasse + mineral mixture); n = 24] or control group [(CON) - same basal diet + based-plant supplement [40% of crude protein, 3.5 g/kg of body weight (BW); n = 19]. From 200 d of gestation until parturition, all cows were equally fed corn silage and mineral mixture. During the cow-calf phase, cows and their calves were maintained in a pasture area. After weaning, calves were individually housed and evaluated during the backgrounding (255 to 320 d), growing 1 (321 to 381 d), and growing 2 (382 to 445 d) phases. Offspring's blood samples were collected at 210 and 445 d of age. Samples of skeletal muscle tissue were collected through biopsies at 7, 30, and 445 d of age. Muscle tissue samples were subjected to reverse-transcription quantitative polymerase chain reaction analysis. Prenatal treatment and offspring's sex (when pertinent) were considered fixed effects. The significance level was set at 5%. At mid-gestation, cows supplemented with protein reached 98% and 92% of their protein and energy requirements, while nonsupplemented cows attained only 30% and 50% of these requirements, respectively. The RES offspring were lighter at birth (27 vs. 31 kg), weaning (197 vs. 214 kg), and 445 d of age (398 vs. 429 kg) (P ≤ 0.05). The CON calves had greater (P < 0.05) morphometric measurements overall. The CON offspring had ~26% greater muscle fiber area (P ≤ 0.01). There was a trend (P = 0.06) for a greater Mechanistic target of rapamycin kinase mRNA expression in the Longissimus thoracis in the CON group at 7 d of age. The Myogenic differentiation 1 expression was greater (P = 0.02) in RES-females. Upregulation of Carnitine palmitoyltransferase 2 was observed in RES offspring at 445 d (P = 0.04). Expression of Fatty acid binding protein 4 (P < 0.001), Peroxisome proliferator-activated receptor gamma (P < 0.001), and Stearoyl-Coenzyme A desaturase (P < 0.001) was upregulated in CON-females. Therefore, protein supplementation during gestation enhances offspring growth and promotes favorable responses to lipogenesis, particularly in females.

Can the post-ruminal urea release impact liver metabolism, and nutritional status of beef cows at late gestation?

We aimed to evaluate the effects of post-ruminal supply of urea (PRU) on nutritional status, and liver metabolism of pregnant beef cows during late gestation. Twenty-four Brahman dams, pregnant from a single sire, and weighing 545 kg ± 23 kg were confined into individual pens at 174 ± 23 d of gestation, and randomly assigned into one of two dietary treatments up to 270 d of gestation: Control (CON, n = 12), consisting of a basal diet supplemented with conventional urea, where the cows were fed with diets containing 13.5 g conventional urea per kg dry matter; and PRU (PRU, n = 12), consisting of a basal diet supplemented with a urea coated to extensively prevent ruminal degradation while being intestinally digestible, where the cows were fed with diets containing 14,8 g urea protected from ruminal degradation per kg dry matter. Post-ruminal supply of urea reduced the urine levels of 3-methylhistidine (P = 0.02). There were no differences between treatments for dry matter intake (DMI; P = 0.76), total digestible nutrient (TDN) intake (P = 0.30), and in the body composition variables, such as, subcutaneous fat thickness (SFT; P = 0.72), and rib eye area (REA; P = 0.85). In addition, there were no differences between treatments for serum levels of glucose (P = 0.87), and serum levels of glucogenic (P = 0.28), ketogenic (P = 0.72), glucogenic, and ketogenic (P = 0.45) amino acids, neither for urea in urine (P = 0.51) as well as urea serum (P = 0.30). One the other hand, enriched pathways were differentiated related to carbohydrate digestion, and absorption, glycolysis, pyruvate metabolism, oxidative phosphorylation, pentose phosphate pathway, and biosynthesis of amino acids of the exclusively expressed proteins in PRU cows. Shifting urea supply from the rumen to post-ruminal compartments decreases muscle catabolism in cows during late gestation. Our findings indicate that post-ruminal urea supplementation for beef cows at late gestation may improve the energy metabolism to support maternal demands. In addition, the post-ruminal urea release seems to be able to trigger pathways to counterbalance the oxidative stress associated to the increase liver metabolic rate.

Nutrient supplementation of beef female calves at pre-weaning enhances the commitment of fibro-adipogenic progenitor cells to preadipocytes

We aimed to evaluate the impact of nutrient supplementation of beef female calves at pre-weaning on adipogenic determination. Thirty-four female calves were assigned to two experimental treatments: Control (CON, n = 17), where animals were supplemented only with mineral mixture; Supplemented (SUP, n = 17), where animals received energy-protein supplement containing minerals (5 g/kg of BW per day) of their body weight. Animals were supplemented from 100 to 250 days of age, and muscle samples were biopsied at the end of the supplementation period. Regarding the performance variables, there were no differences between treatments for initial body weight (P = 0.75). The final body weight (P = 0.07), average daily gain (P = 0.07), rib eye area (P = 0.03), and rib fat thickness (P = 0.08) were greater in SUP female calves compared with CON treatment. The number of fibro-adipogenic progenitor cells (P = 0.69) did not differ between treatments, while a greater number of intramuscular pre-adipocytes were observed in SUP than CON female calves (P = 0.01). The expression of miRNA-4429 (P = 0.20) did not differ between treatments, while the expression of miRNA-129-5p (P = 0.09) and miRNA-129-2-3p (P = 0.05) was greater in CON than SUP female calves. Our results suggest that nutrient supplementation at early postnatal stages of development enhances the commitment of fibro-adipogenic progenitor cells into the adipogenic lineages allowing to an increase in intramuscular fat deposition potential of the animals later in life.

Heat stress promotes adaptive physiological responses and alters mrna expression of ruminal epithelium markers in Bos taurus indicus cattle fed low- or high-energy diets

This research aimed to evaluate the impact of temperature and energy status on the thermal indices, physiological parameters, and ruminal papilla mRNA expression levels of Zebu beef heifers (Bos taurus indicus). In this trial, we used six ruminal-cannulated Nellore females. The experimental design was a 6 × 6 Latin square, with six treatments and six periods. The research used a 2 × 2 + 2 factorial scheme. The arrangement comprised: two thermal conditions [thermoneutrality (TN; 21.6 °C) or heat stress (HS, 34 °C)]; two dietary energy levels (low or high-energy); and two additional treatments, with heifers exposed to the TN, but pair-fed with females exposed to HS (PFTN). For our purposes, body temperature, heart and respiratory rates were measured and the relative mRNA expression was quantified using the PCR-RT technique. Compared to TN or PFTN, the HS increased the body temperature measurements in the morning and evening (p ≤ 0.04). Heart rate was 22% greater for heifers under HS than for TN (p < 0.01) and 13% higher for those under HS than PFTN (p = 0.03) in the morning. Respiratory rates increased with HS exposure compared to TN or PFTN (p < 0.01). Heifers submitted to HS and fed low-energy diets had and tended to have lower caspase 3 (CASP3, p <i=></i> 0.001) and sodium-glucose cotransporter type 1 (SGLT1; p = 0.17) mRNA expressions, respectively. Heat-stressed heifers fed low-energy diets also increased the putative anion transporter (PAT1; p ≤ 0.01) mRNA expressions by 60%. Heifers under HS-fed high-energy diets had greater kallikrein-related peptidase (KLK) 9 expressions (p = 0.02), while KLK10 (p = 0.11) tended to be up-regulated in heifers in TN-fed a low-energy diets. In conclusion, heat stress down-regulated the mRNA expression of rumen markers related to short-chain fatty acids transport and pH modulation.

PSIII-A-13 Intramuscular fat and Expression of Genes Involved in Lipid Metabolism and Gluconeogenesis in Nellore Bulls fed Snaplage

We hypothesized that diets with snaplage would increase the expression of lipogenic genes, resulting in higher marbling fat content, compared to a diet of whole-plant silage and reconstituted corn silage. Therefore, the objective of this study was to analyze the chemical composition, as well as the expression of genes involved in lipid metabolism and liver gluconeogenesis of Nellore bulls fed snaplage. Seventy-two Nellore bulls (24 months, initial body weight 400 ±27.4 kg) were used in a completely randomized design. Animals were stratified by body weight, housed in 24 pens (3 animals per pen), and designed to one of the three treatments (8 pens per treatment). Experimental diets (around 14% of crude protein) were: control (corn silage, ground and reconstituted corn grain, protein sources), snaplage + ground corn, replacing completely corn silage (SNAP65, with 65% snaplage), and snaplage 85, replacing completely corn silage and corn grain (SNAP85, with 85% snaplage). Data were analyzed using MIXED procedure of SAS 9.4 with fixed effects of dietary treatment, and random effects of pen nested within treatment. Overall, diets did not affect (P&gt;0.11) the intramuscular fat. However, animals fed SNAP85 showed higher PPARG expression (P=0.03). The muscle of animals fed snaplage (SNAP65 and SNAP85) also had higher expression of ACACA and SCD1 genes (P≤0.03) than the control animals. The FABP4 expression tended to be higher (P=0.10) in the muscle of animals fed SNAP85 compared with SNAP65. In addition, animals fed control diet tended to have higher (P=0.07) expression of PC in the liver compared with animals fed SNAP65 and SNAP85. Also, PEPCK2 expression was lower (P=0.05) in in the liver of animals fed SNAP65 diet than control SNAP85. We conclude that diets with snaplage increased the expression of genes involved in the muscle lipogenesis, without increase intramuscular fat.

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162 Fetal Programming and Meat Quality

For many years, variation in carcass and meat quality traits was thought to result from actions taken throughout the animals’ life after birth. However, the quantity and quality of meat obtained at slaughter are not always as good as expected. The past decade has increased the number of evidence of the effects of intrauterine development of skeletal muscle on animal performance that affects the carcass and meat quality traits. The so-called “Fetal Programming” concept sheds light on the biology of skeletal muscle development in meat animals, revealing that this development stage appears to be a pivotal moment to invest efforts aiming to improve animal productivity and the quality of meat. Because most, if not all, of the muscle fibers are formed prenatally in livestock species, the impairment of muscle fiber formation at this stage will limit the overall muscle mass deposition throughout postnatal life. Intramuscular adipocytes also start their formation at the fetal stage. As such, since the intramuscular fat depot has a lower deposition rate than other fat depots, enhancement of intramuscular adipogenesis during the fetal stage may increase marbling deposition postnatally. Muscle fibers, adipocytes, and fibroblasts, which contribute to connective tissue formation, are derived from the same pool of mesenchymal stem (MS) cells. Depending on the insult suffered during intrauterine development, their commitment may shift from myogenic towards adipogenic/fibrogenic lineage. So far, most of the evidence in livestock animals has shown that maternal nutrition during gestation is the main factor that influences the mechanisms underlying the commitment of the MS cells. Although the majority of these studies have shown the consequences of maternal nutrition on myogenesis, adipogenesis, and fibrogenesis, the epigenetic markers that cause the programming of MS cells to undergo to one lineage or another needs to be further investigated.

The efficacy of 8-hydroxyquinoline derivatives in controlling the fungus Ilyonectria liriodendri, the causative agent of black foot disease in grapevines

AIM

The purpose of this study was to evaluate the in vitro and in vivo efficiency of derivatives of 8-Hydroxyquinoline (8HQ) in controlling the fungus Ilyonectria liriodendri.

METHODS AND RESULTS

The in vitro tests consisted of assessing its susceptibility to the minimal inhibitory concentration (MIC) and the inhibition of mycelial growth. While the in vivo tests consisted of applying and assessing the most effective products for the protection of wounds, in both preventive + curative and curative forms. The MIC values for PH 151 (6·25 µg ml^-1 ) showed better results when compared to the fungicides tebuconazole (>50 µg ml^-1 ) and mancozeb (12·5 µg ml^-1 for strain 176 and 25 µg ml^-1 for strain 1117). PH 151 significantly inhibited mycelial growth, while mancozeb did not differ from the control. In in vivo tests, PH 151 again demonstrated excellent results in vitro, especially when applied preventively.

CONCLUSIONS

The derivative of 8HQ PH 151 was effective in controlling the fungus I. liriodendri in vitro and proved to be a promising option for protecting wounds.

SIGNIFICANCE AND IMPACT OF THE STUDY

This study points to the prospect of an effective and safe preventive antifungal product, which would enable the use of pesticides in vine culture to be reduced.

Predicting the chemical composition of the body and the carcass of hair sheep using body parts and carcass measurements

Determination of the chemical composition in the body and carcass of ruminants is important for both nutritional requirement studies and the meat industry. This study aimed to develop equations to predict the body and carcass chemical composition of hair sheep using the chemical composition of body parts, carcass measurements and shrunk BW as predictors. A database containing 107 individual records for castrated male hair sheep ranging from 24 to 43 kg BW was gathered from two body composition studies. The empty body, carcass and body parts were analyzed for water, ash, fat and protein contents (%). The body parts used to estimate body and carcass composition were fore leg, hind leg and 9-11th rib section. The carcass measurements used were leg length, thoracic circumference, hind circumference, hind width, thoracic width, thoracic depth and chest width. Each model performance was evaluated using a leave-one-out cross-validation. Multiple regression analysis considering the study as a random effect revealed that body parts in association with carcass measurements were significant for predicting the chemical composition in the body of castrate male sheep. However, the use of the chemical composition of hind leg produced the best models for predicting the ash and fat contents in the empty body, whereas the water and protein contents in the empty body were better predicted when using the chemical compositions of 9-11th rib section and fore leg, respectively. Multiple regression analysis also revealed that most body parts were suitable for predicting the carcass composition, except for 9-11th rib section whose chemical composition did not produce significant prediction equations for ash and protein carcass contents. The use of the chemical composition of hind leg in association with carcass measurements produced the best models for predicting the water and fat contents in the carcass, while the ash and protein contents in the carcass were better predicted when using the chemical composition of fore leg. In conclusion, precision, accuracy and goodness-of-fit of the equations drove the selection of the chemical composition of hind leg and carcass measurements in a multivariate approach, as the most suitable predictors of the chemical composition of the body and carcass of hair sheep. However, the chemical composition of fore leg may be used as well. The developed equations could improve the accuracy of the empty body and carcass composition estimations in sheep, optimizing the estimation of nutrient requirements, as well as the carcass quality evaluation for this species.

PSVII-10 Skeletal muscle transcriptome reveals gene expression differences in newborn goats' as a result of maternal feed restriction at different stages of gestation

The current study aimed to identify differentially expressed genes and their biological process in the skeletal muscle of newborn goats as a function of maternal feed restriction during different stages of gestation. A total of 14 pregnant dams were randomly divided into one of the follow dietary treatments: Animals fed at 50% of maintenance requirement from 8-84 d of gestation and then fed at 100% of maintenance requirement from day 85 of gestation to parturition (RM, n = 6), and animals fed at 100% of maintenance requirement from 8-84 d of gestation and then fed at 50% of maintenance requirement from day 85 of gestation to parturition (MR, n = 8). At birth, all male offspring were euthanized and a sample of Logissimus muscle was collected for total RNA extraction and sequencing. Cuffdiff tool (Cufflinks 2.2.1) was used to count reads, normalize transcript expression (FPKM), and identify differentially expressed genes (DEG) between treatments. Network analysis was performed with String 11.0 using the available genome from the closest specie (Ovis aries). A total of 66 DEG (q-value &lt; 0.05) were identified, with 6 up-regulated genes in skeletal muscle of RM compared to MR newborn goats. These genes are related to tissue development, such as CYTL1, UGT8, and NPNT. The 60 down-regulated genes in skeletal muscle of RM compared with MR newborn goats are related to transcription factors (TF) complex. Among the TF, FOS and JUNB families forms heterodimers in response to several stimuli (cytokines,growth factors, stress), and play key roles controlling a number of cellular processes, including signal transduction, cell proliferation, differentiation and apoptosis. In conclusion, maternal feed restriction at different stages of gestation affects tissue development and changes the transcription pattern in the skeletal muscle of newborn goats, which may lead to negative consequences in animal growth and performance.

PSVII-9 Post transcriptional modifications may lead to changes in newborn goats’ skeletal muscle proteome as a consequence of maternal feed restriction at different stages of gestation

We aimed to investigate the impact of maternal feed restriction at different stages of gestation on proteomic profile in the skeletal muscle of newborn goats. A total of 14 pregnant dams were randomly divided into one of the follow dietary treatments: Animals fed at 50% of maintenance requirement from 8-84 d of gestation and then fed at 100% maintenance requirement from day 85 of gestation to parturition (RM, n = 6), and animals fed at 100% of maintenance requirement from 8-84 d of gestation and then fed at 50% maintenance requirement from day 85 of gestation to parturition (MR, n = 8). Longissimus muscle was sampled from male newborn goats and submitted to sarcoplasmic protein extraction and liquid chromatography coupled to mass spectrometry (LC-MS) analysis. The raw data were processed with MaxQuant (1.6.3.3) software with parameters set to default values. Label-free quantification (LFQ) was added and only protein ratios calculated from at least two unique peptides were considered. Our data showed 3 differentially expressed proteins down-regulated in RM (q-value &lt; 0.05). Additionally, we observed proteins present exclusively in each treatment (RM= 137 proteins; MR= 41 proteins). The overall enriched pathways in RM newborn goats are associated with glycolysis (PKM), NADPH synthesis (PGD), lipid oxidation (ECHS1, ACAT1) and citrate cycle (ACO1, OGDH). While the overall enriched pathways in MR newborn goats are associated with glycolysis/gluconeogenesis (GAPDH, ENO) and citrate cycle (PDHA, IDH3A). In addition, correlation analysis between shotgun proteomics and RNAseq data from the same samples showed that there were no relationships between proteins and transcripts observed. These results indicate that maternal feed restriction during different stages of gestation alters enzymes and protein domains abundance associated with nucleotide metabolism in the skeletal muscle of newborn goats. Moreover, the lack of correlation between protein-transcript suggests the importance of post-transcriptional regulation of skeletal muscle metabolism as a consequence of maternal feed restriction at different stages of gestation.

PSVII-5 Effect of maternal feed restriction at different stages of gestation on development of gastrointestinal tract of newborn goats

We assessed the effect of maternal feed restriction at different stages of gestation on growth and development of organs and small intestine of newborn goats. A total of 14 pregnant dams were randomly divided into one of the follow dietary treatments: Animals fed at 50% of maintenance requirement from 8-84 d of gestation and then fed at 100% maintenance requirement from day 85 of gestation to parturition (R-M, n = 6), and animals fed at 100% of maintenance requirement from 8-84 d of gestation and then fed at 50% maintenance requirement from day 85 of gestation to parturition (M-R, n = 8). At birth, newborns were slaughtered for collection of corporal components. No differences were observed among treatments for birth weight (P = 0.46). The weight of the complex reticulum-rumen-omasum tended to be heavier (P = 0.057) in the M-R group, when expressed per kg of body weight. The small intestine (P = 0.038) and total intestine (P = 0.038) were heavier in the offspring of the M-R group when expressed in kg of body weight. The M-R newborns had greater length of the small intestine (P = 0.043) and total intestine (P = 0.026). Maternal feed restriction did not influence the intestinal villi height (P = 0.406). However, newborn from R-M group had lower villus height:crypt depth ratio (P = 0.016), due to the tendency of the greater of crypt depth in these animals (P = 0.081). No differences among treatments were observed in mRNA expression of the MGAM and GLP-2R in the jejunum of the offspring (P &gt; 0.12). Newborns of the M-R group tended to present greater mRNA abundance of the SLC5A1 (P = 0.091), SLC2A2 (P = 0.091), and OCLN (P = 0.061). In summary, restriction in the first half of gestation may be more detrimental to the performance and health of offspring throughout life due to increased impairment of intestinal development.

PSVII-2 Differentially expressed genes and their biological function in skeletal muscle of calves born from cows with or without protein supplementation during mid-gestation

Gestating cows have an increased nutrient demand to meet the needs of developing the fetus and the mid-gestation is a critical period for the fetal skeletal muscle development. The aim of this study was to evaluate the skeletal muscle transcriptome in the progeny as a function of the maternal protein nutrition during mid-gestation. Eleven Tabapuã cows and their male calves were used in this study. In the first third of gestation (0 to 100 days of gestation; dg), all cows were kept on pasture. From 100 to 200 dg, the control group (CTRL; 7 animals) received a basal diet achieving 5.5% crude protein (CP), whereas the supplemented group (SUPPL; 4 animals) received a basal diet plus protein supplementation (40% CP). After 200 dg, all animals received the same diet. Weaning was performed at 205 ± 7.5 days of age and animals were kept on pasture until reaching 240 days of age, when they were transferred to a feedlot. Muscle samples were collected at 260 days of age and RNA was extracted for RNA-seq analysis. Gene expression data was analyzed with a negative binomial model to identify (q-value ≤ 0.05) differentially expressed genes (DEG) between treatments. A total of 716 DEG were identified (289 DEG up-regulated and 427 down-regulated in SUPPL group; q-value ≤ 0.05). From the 10 most significant down-regulated DEG in the SUPPL group, two genes associated with apoptotic process were identified: MAPK8IP1 and GRINA, with log2 Fold-Changes (log2FC) of 1.04 and 0.49, respectively. From the 10 most significant up-regulated DEG in the SUPPL group, mTOR was identified, with log2FC=0.31. This is a well-known gene involved in muscle protein synthesis. In conclusion, maternal protein supplementation during mid-gestation affects the expression of genes related to energy metabolism and muscle development, which can lead to long-term impacts on production efficiency.

Effects of grazing management in brachiaria grass-forage peanut pastures on canopy structure and forage intake1

Maintenance of mixed grass-legume pastures for stand longevity and improved animal utilization is a challenge in warm-season climates. The goal of this study was to assess grazing management on stand persistence, forage intake, and N balance of beef heifers grazing mixed pastures of Brachiaria brizantha and Arachis pintoi. A 2-yr experiment was carried out in Brazil, where four grazing management were assessed: rest period interrupted at 90%, 95%, and 100% of light interception (LI) and a fixed rest period of 42 d (90LI, 95LI, 100LI, and 42D, respectively). The LI were taken at 50 points at ground level and at 5 points above the canopy for each paddock using a canopy analyzer. For all treatments, the postgrazing stubble height was 15 cm. Botanical composition and canopy structure characteristics such as canopy height, forage mass, and vertical distribution of the morphological composition were evaluated pre- and post-grazing. Forage chemical composition, intake, and microbial synthesis were also determined. A randomized complete block design was used, considering the season of the year as a repeated measure over time. Grazing management and season were considered fixed, while block and year were considered random effects. In the summer, legume mass accounted for 19% of the canopy at 100LI, which was less than other treatments (a mean of 30%). The 100LI treatment had a greater grass stem mass compared with other treatments. In terms of vertical distribution for 100LI, 38.6% of the stem mass was above the stubble height, greater than the 5.7% for other treatments. The canopy structure limited NDF intake (P = 0.007) at 100LI (1.02% of BW/d), whereas 42D, 90LI, and 95LI treatments had NDF intake close to 1.2% of BW/d. The intake of digestible OM (P = 0.007) and the ratio of CP/digestible OM (P < 0.001) were less at 100LI in relation to the other treatments. The production of microbial N (P < 0.001) and efficiency of microbial synthesis (P = 0.023) were greater at 95LI and 90LI, followed by 42D and less at 100LI. Overall, the range from 90% to 95% of LI is the recommendation to interrupt the rest period, since this strategy enhanced community stability, forage intake, and nutritional value of the diet. Under on-farm conditions, brachiaria grass and forage peanut pastures should be managed at a range height of 24 to 30 cm.

Differentially expressed mRNAs, proteins and miRNAs associated to energy metabolism in skeletal muscle of beef cattle identified for low and high residual feed intake

Background

Feed efficiency is one of the most important parameters that affect beef production costs. The energy metabolism of skeletal muscle greatly contributes to variations in feed efficiency. However, information regarding differences in proteins involved in the energy metabolism of the skeletal muscle in beef cattle divergently identified for feed efficiency is scarce. In this study, we aimed to investigate energy metabolism of skeletal muscle of Nellore beef cattle, identified for low and high residual feed intake using a proteomics approach. We further assessed the expression of candidate microRNAs as a one of the possible mechanisms controlling the biosynthesis of the proteins involved in energy metabolism that were differentially abundant between high and low residual feed intake animals.

Results

A greater abundance of 14–3-3 protein epsilon (P = 0.01) was observed in skeletal muscle of residual feed intake (RFI) high animals (RFI-High). Conversely, a greater abundance of Heat Shock Protein Beta 1 (P < 0.01) was observed in the skeletal muscle of RFI-Low cattle. A greater mRNA expression of YWHAE, which encodes the 14–3-3 protein epsilon, was also observed in the skeletal muscle of RFI-High animals (P = 0.01). A lower mRNA expression of HSPB1, which encodes the Heat Shock Protein Beta 1, was observed in the skeletal muscle of RFI-High animals (P = 0.01). The miR-665 was identified as a potential regulator of the 14–3-3 protein epsilon, and its expression was greater in RFI-Low animals (P < .001). A greater expression of miR-34a (P = 0.01) and miR-2899 (P < .001) was observed in the skeletal muscle of RFI-High animals, as both miRNAs were identified as potential regulators of HSPB1 expression.

Conclusion

Our results show that Nellore cattle divergently identified for feed efficiency by RFI present changes in the abundance of proteins involved in energy expenditure in skeletal muscle. Moreover, our data point towards that miR-665, miR34a and miR-2899 are likely involved in controlling both 14-3-3 epsilon and HSPB1 proteins identified as differentially abundant in the skeletal muscle of RFI-High and RFI-Low Nellore cattle.

Electronic supplementary material

The online version of this article (10.1186/s12864-019-5890-z) contains supplementary material, which is available to authorized users.

Effect of maternal feed restriction in dairy goats at different stages of gestation on skeletal muscle development and energy metabolism of kids at the time of births

The aim was to determine effects of maternal feed restriction in dairy goats at gestational different stages on skeletal muscle development and energy metabolism in kids at birth. Six pregnant goats were fed 50% of total digestible nutrients (TDN) and crude protein (CP) (NRC, 2007) recommendations in the first half of gestation and then fed to 100% of the recommendations in the second half of gestation (treatment R-M). In the other group, eight pregnant goats were fed 100% of TDN and CP in the first half of gestation and 50% of a restricted diet the second half of gestation (treatment M-R). Birth weight, blood glucose concentration, muscle fiber number, and size of kids at birth were not affected by maternal feed restriction. The mRNA and protein abundance of myogenic, adipogenic and fibrogenic markers were not affected (P > 0.05) by maternal diet. With regard to values for variables in kid energy metabolism, mRNA abundance of the glycolic enzyme HKII was less (P = 0.03) in the M-R group. In conclusion, maternal feed restriction in the first or second half of gestation had no affect mRNA abundance on myogenic, adipogenic, and fibrogenic markers nor were there changes in skeletal muscle mesenchymal stem cell population of kids at the time of birth. There, however, may be detrimental effects on energy metabolism by reducing HKII gene expression in skeletal muscle of dairy goat kids at the time of birth.

TRIENNIAL GROWTH AND DEVELOPMENT SYMPOSIUM: Dedifferentiated fat cells: Potential and perspectives for their use in clinical and animal science purpose

An increasing body of evidences has demonstrated the ability of the mature adipocyte to dedifferentiate into a population of proliferative-competent cells known as dedifferentiated fat (DFAT) cells. As early as the 1970s, in vitro studies showed that DFAT cells may be obtained by ceiling culture, which takes advantage of the buoyancy property of lipid-filled cells. It was documented that DFAT cells may acquire a phenotype similar to mesenchymal stem cells and yet may differentiate into multiple cell lineages, such as skeletal and smooth muscle cells, cardiomyocytes, osteoblasts, and adipocytes. Additionally, recent studies showed the ability of isolated mature adipocytes to dedifferentiate in vivo and the capacity of the progeny cells to redifferentiate into mature adipocytes, contributing to the increase of body fatness. These findings shed light on the potential for use of DFAT cells, not only for clinical purposes but also within the animal science field, because increasing intramuscular fat without excessive increase in other fat depots is a challenge in livestock production. Knowledge of the mechanisms underlying the dedifferentiation and redifferentiation of DFAT cells will allow the development of strategies for their use for clinical and animal science purposes. In this review, we highlight several aspects of DFAT cells, their potential for clinical purposes, and their contribution to adipose tissue mass in livestock.

Nutrigenomics and Beef Quality: A Review about Lipogenesis

The objective of the present review is to discuss the results of published studies that show how nutrition affects the expression of genes involved in lipid metabolism and how diet manipulation might change marbling and composition of fat in beef. Several key points in the synthesis of fat in cattle take place at the molecular level, and the association of nutritional factors with the modulation of this metabolism is one of the recent targets of nutrigenomic research. Within this context, special attention has been paid to the study of nuclear receptors associated with fatty acid metabolism. Among the transcription factors involved in lipid metabolism, the peroxisome proliferator-activated receptors (PPARs) and sterol regulatory element-binding proteins (SREBPs) stand out. The mRNA synthesis of these transcription factors is regulated by nutrients, and their metabolic action might be potentiated by diet components and change lipogenesis in muscle. Among the options for dietary manipulation with the objective to modulate lipogenesis, the use of different sources of polyunsaturated fatty acids, starch concentrations, forage ratios and vitamins stand out. Therefore, special care must be exercised in feedlot feed management, mainly when the goal is to produce high marbling beef.

Achieving body weight adjustments for feeding status and pregnant or non-pregnant condition in beef cows

BACKGROUND

Beef cows herd accounts for 70% of the total energy used in the beef production system. However, there are still limited studies regarding improvement of production efficiency in this category, mainly in developing countries and in tropical areas. One of the limiting factors is the difficulty to obtain reliable estimates of weight variation in mature cows. This occurs due to the interaction of weight of maternal tissues with specific physiological stages such as pregnancy. Moreover, variation in gastrointestinal contents due to feeding status in ruminant animals is a major source of error in body weight measurements.

OBJECTIVES

Develop approaches to estimate the individual proportion of weight from maternal tissues and from gestation in pregnant cows, adjusting for feeding status and stage of gestation.

METHODS AND FINDINGS

Dataset of 49 multiparous non-lactating Nellore cows (32 pregnant and 17 non-pregnant) were used. To establish the relationships between the body weight, depending on the feeding status of pregnant and non-pregnant cows as a function of days of pregnancy, a set of general equations was tested, based on theoretical suppositions. We proposed the concept of pregnant compound (PREG), which represents the weight that is genuinely related to pregnancy. The PREG includes the gravid uterus minus the non-pregnant uterus plus the accretion in udder related to pregnancy. There was no accretion in udder weight up to 238 days of pregnancy. By subtracting the PREG from live weight of a pregnant cow, we obtained estimates of the weight of only maternal tissues in pregnant cows. Non-linear functions were adjusted to estimate the relationship between fasted, non-fasted and empty body weight, for pregnant and non-pregnant cows.

CONCLUSIONS

Our results allow for estimating the actual live weight of pregnant cows and their body constituents, and subsequent comparison as a function of days of gestation and feeding status.

Predicting efficiency of use of metabolizable energy to net energy for gain and maintenance of Nellore cattle

Twenty-six comparative slaughter studies were used (n = 752 animals) and coded within each experiment by gender (431 bulls, 204 steers, and 117 heifers) and breed (447 Nellore and 305 Bos indicus and Bos taurus crossbreds) to develop equations to predict the efficiency of use of ME to NE for growth (kg) and ME to NE for maintenance (km). The retained energy (RE) was regressed on ME intake (MEI) available for gain using orthogonal regression to obtain the kg within each experiment. The estimated kg was regressed on RE as protein (REp) according to the following equation: kg = a/(b + REp). Gender and breed effects were not tested because of limited number of experiments. The km was estimated as the intercept of the following equation: HP = β0 × e((β1 × MEI)), in which HP is heat production, β0 and β1 are coefficients, and e is the natural logarithm. The ME for maintenance (MEm) was computed assuming MEI equals to HP at maintenance. The km was obtained using the stepwise procedure of a multiple regression including ADG, empty body gain (EBG), empty BW (EBW), EBW(0.75), kg, and energy content in the EBW. A random coefficient model, assuming a random variation for study effects, was used to test breed and gender effects to identify the best model to estimate km. The overall equation to predict kg was 0.327 (±0.142)/[0.539 (±0.317) + REp], with an R(2) of 0.963. The equation to predict km was 0.513 (±0.024) + 0.173 (±0.061) × kg + a × EBG, R(2) = 0.92, in which a = 0.100 (±0.021) for B. indicus or a = 0.073 (±0.021) for crossbreds. Our results indicated that B. indicus were more efficient to use ME for maintenance. We concluded that km can be predicted from kg and EBG and that B. indicus × B. taurus crossbreds can affect km. Furthermore, kg can be predicted from REp and neither gender nor crossbreeding (B. indicus × B. taurus) affected kg. Because our database consisted of Nellore and B. indicus and B. taurus crossbreds, it is necessary to further evaluate differences between B. taurus and B. indicus regarding the kg.

Effects of pregnancy and feeding level on carcass and meat quality traits of Nellore cows

Carcass and meat quality traits of 16 pregnant and 5 non-pregnant cows fed at 1.2 times maintenance and 16 pregnant and 6 non-pregnant fed ad libitum were evaluated. Pregnancy did not affect final body weight (FBW; P=0.0923), cold carcass yield (CCY; P=0.0513), longissimus muscle area (LMA; P=0.8260), rib fat thickness (RFT; P=0.1873) and shear force (WBSF; P=0.9707). A lower FBW (P=0.0028), LMA (P=0.0048) and RFT (P=0.0001) were observed in feed restricted cows. However, no differences were found for CCY (P=0.7243) and WBSF (P=0.0759) among feeding level groups. These data suggests that carcass and meat quality traits are not affected by pregnancy status in Nellore cows. Moreover, although cows experiencing feed restriction did have reduced deposition of subcutaneous fat and lean tissue, there were no major impacts on meat quality traits.