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This study evaluated the effect of maternal protein supplementation during mid or late gestation on energy metabolism of the skeletal muscle of beef calves. Sixteen pregnant cows were divided into 3 groups: CTRL (not supplemented); MID (supplemented from 30 to 180 days of gestation); and LATE (supplemented from 181 to 281 days of gestation). The supplement contained 30% crude protein. Thirty days after birth, blood and muscle samples of the calves were collected for analyses of gene expression, proteins, and metabolites. No differences (P ≥ 0.15) in birth weight, performance at weaning, or muscle expression of the genes evaluated (P ≥ 0.21) were observed. Calves born to CTRL cows had a lower ratio (P = 0.03) of p-AMPK/AMPK protein in the skeletal muscle. Calves born to MID cows had lower (P = 0.04) glucose concentration than those born to LATE cows. Changes in p-AMPK/AMPK protein, indicated a possible metabolic inflexibility in the skeletal muscle of calves born to CTRL cows. These results indicated that lack of protein supplementation in pregnant cows alter the energy metabolism of their calves and reflect in a metabolic inflexibility. RESUMO: O objetivo deste estudo foi avaliar o efeito da suplementação proteica materna sobre o metabolismo energético do músculo esquelético de bezerros de corte. Dezesseis matrizes gestantes foram divididas em três grupos: CONTROLE (não suplementado); MÉDIO (suplementados entre 30 e 180 dias de gestação); e FINAL (suplementado entre 181 e 281 dias de gestação). O suplemento continha 30% de proteína bruta e foi fornecido em quantidades totais iguais aos tratamentos. Trinta dias após o nascimento, amostras de sangue e músculo dos bezerros foram coletadas para análises de expressão gênica, abundância de proteínas e metabólitos. Não foram observadas diferenças (P ≥ 0,15) no peso ao nascimento ou parâmetros de desempenho ao desmame, bem como na expressão dos genes avaliados (P ≥ 0,21). Os bezerros nascidos de matrizes do tratamento CONTROLE apresentaram menor proporção (P = 0,03) de proteína p-AMPK/AMPK no músculo esquelético. Os bezerros nascidos de matrizes do tratamento MÉDIO apresentaram concentração de glicose menor (P = 0,04) do que aqueles nascidos de matrizes do tratamento FINAL. Os resultados observados indicam que a ausência de suplementação proteica em matrizes gestantes pode alterar o metabolismo energético da progênie e refletir em uma inflexibilidade metabólica, a qual pode ocasionar limitações quanto à eficiência energética do tecido muscular esquelético e consequentemente, limitar o desempenho da progênie ao longo da fase pós-natal.

The productive traits of beef cattle are orchestrated by their genetics, post-natal environmental conditions, and also by the intrauterine background. Both under- or overnutrition, as specific dietary components, are able to promote persistent effects on the offspring. This occurs because dietary factors act not only affecting the availability of substrates for fetal anabolism and oxidative metabolism, but also as signals that regulate several events toward fetal development. Therefore, this study aimed to summarize the gestational nutrition effects on the offspring performance and meat quality in a long term. Overall, studies have shown that many of these alterations are under the control of epigenetic mechanisms, as DNA methylation, histones modification, and non-coding RNA. The current knowledge has indicated that the fetal programming responses are dependent on the window of fetal development in which the dietary treatment is applied, the intensity of maternal nutritional stimuli, and the treatment application length. Collectively, studies demonstrated that muscle cell hyperplasia is impaired when maternal requirements were not achieved in the second third of gestation, which limits the formation of a greater number of muscle fibers and the offspring growth potential in a long term. Changes in muscle fibers metabolism and in collagen content were also reported as consequence of a dietary perturbation during pregnancy. In contrast, a maternal overnutrition during the late pregnancy has been associated with beneficial responses on meat quality. In summary, ensuring an adequate maternal environment during the fetal development is crucial to enhance the productive responses in beef cattle operations.

Since nutritional requirements are increased at the end of gestation to meet the demands of the pregnant uterus, pregnant beef cows are susceptible to mobilization of body reserves (mainly fat and amino acids (AAs)) and to alter the metabolism of nutrients in the liver and muscle to support such demands. The objective of this study was to evaluate the effect of CP supplementation on maternal nutrient metabolism in the late gestation of beef cows grazing a low-quality pasture. Forty-three pregnant Nellore cows gestating male fetuses (average age = 6 years; average weight = 544 kg) at 193 ± 30 (mean ± SD) days (d) of gestation were divided into eight groups (experimental units, with four to five cows each). Treatments were (1) control (CON, n = 4): pasture-based (PB) diet without CP supplementation and (2) supplemented (SUP, n = 4): PB diet daily supplemented with 2 g/kg of BW of a 43.5% CP supplement. Liver and skeletal muscle biopsies were performed at 265 days of gestation and samples were collected for mRNA expression. On day 280 of gestation, blood samples were collected to assess plasma levels of AA. The CON-fed cows tended to have greater (P = 0.057) total circulating AA than SUP-fed cows. The circulating glycogenic AA was greater (P = 0.035) in CON than in SUP cows. CON cows was greater for histidine (P = 0.015), methionine (P = 0.007) and alanine (P = 0.036) than SUP cows. The CON- and SUP-fed showed no differences for gluconeogenesis, fatty acid transport and signaling axis markers in the liver. The mRNA expression of markers for skeletal muscle synthesis, p7056k (P = 0.060) and GSK3B (P = 0.096), tended to be greater in cows from CON than SUP group. No differences were found for mRNA expression of markers for skeletal muscle degradation. We conclude that CP supplementation to CP-restricted late-pregnant beef cows reduces the maternal tissue mobilization and changes the profile of plasma circulating AA and the mRNA expression of markers for the synthesis of skeletal muscle tissue.

The aim of this study was to identify whether more and less adapted Angus and Simmental cattle differed in physiological responses and expression of the heat shock factor 1 (HSF1) and the heat shock 70 kDa protein 6 (HSPA6), when subjected to heat stress. Thirty bulls (n = 15 ANG; n = 15 SIM), extremes "more adapted" and "less adapted" within each breed were selected to the heat tolerance test. They were selected according to an index based on the average of the respiratory rate obtained on two hot summer days from one hundred bulls. Before the heat tolerance test day, animals were taken to a paddock with water, grass and shade until 7 a.m. of the following day for morning measurements. They were kept in the barn without access to water and shade until 1 p.m. for the afternoon measurements. Respiratory rate in the morning (MRR) and afternoon (ARR), hair coat surface temperature in the morning (MST) and afternoon (AST), rectal temperature in the morning (MRT) and afternoon (ART) were measured and blood samples were collected for expression analysis of the HSF1 and HSPA6 genes. The MIXED procedure of SAS was used for all statistical analysis. The more adapted Simmental group had lesser values of MRR (P = 0.023) and MRT (P = 0.095), but there was no difference within Angus breed. The ARR was greater (P = 0.004) in less adapted animals for both breeds. The ART was lower in the Simmental breed (P 0.001). Less adapted had greater levels of mRNA of HSF1 (P = 0.06) and HSPA6 (P = 0.09). In conclusion, respiratory rate, rectal temperature and expression of the HSF1 and HSPA6 genes can be indicators of thermotolerance in taurine cattle. Both breeds show physiologically similar responses under heat stress conditions.

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.

Made available in DSpace on 2022-04-28T19:29:44Z (GMT). No. of bitstreams: 0 Previous issue date: 2021-02-01 Context: It is hypothesised that protein supplementation in pregnant Nellore cows during the dry season would improve reproductive performance in the next breeding season, as well as growth, myogenesis and intramuscular lipogenesis of the progeny until weaning. Aims: To evaluate the effect of maternal nutrition on cow reproductive performance, as well as on the growth, myogenesis and lipogenesis of the progeny until weaning. Methods: A total of 92 pregnant cows were fed on pasture, and half of the cows were also fed a mineral-protein supplement (36% crude protein) from 124 ± 21 days of pregnancy to calving. Therefore, two treatments were tested: non-supplemented or supplemented cows. Progeny were weighed after birth, 130 days after birth and at weaning. Six newborn calves from each treatment were slaughtered to collect muscle and jejunum samples to analyse histology and gene expression. In addition, Longissimus thoracis muscle biopsies were collected at 11 days after birth and weaning for gene expression analyses. Key results: Supplemented cows had greater bodyweight (P = 0.03) and body condition score (P = 0.05) during gestation, and the pregnancy rate in the subsequent breeding season had a tendency (P = 0.10) to be greater. The progeny from supplemented cows had greater bodyweight at birth (P = 0.05). However, no differences (P > 0.05) were found in bodyweight at weaning or in the average daily gain during this period. Non-supplemented calves had greater SLC27A4 (P = 0.04) expression and a tendency for greater expression of SLC5A1 (P = 0.08) in the jejunum. Muscle gene expression data showed that progeny from supplemented cows had greater expression of myogenic (WNT10B), adipogenic (PPARG, ZFP423, CD36) and fibrogenic (TGFβ1) markers at birth and at weaning (P ≤ 0.10). Conclusions: In conclusion, protein supplementation of pregnant Nellore cows leads to positive effects for subsequent reproductive performance and for muscle development of their progeny. In addition, the progeny from feed-restricted cows increases prenatal intestinal development for better nutrients absorption under a potentially impaired environmental condition. Implications: The use of protein supplementation in pregnant Nellore cows has a positive impact on the production system, increasing productivity in a cow/calf operation. Department of Animal Science Universidade Federal de Lavras Department of Animal Science Purdue University Agência Paulista de Tecnologia Dos Agronegócios Apta Department of Animal Production Universidade Estadual Paulista Department of Animal Production Universidade Estadual Paulista

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 < 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.

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.

RESUMO As calopsitas são consideradas aves monogâmicas, atingem a maturidade sexual aos 12 meses, com postura variando entre três a sete ovos. São classificadas como granívoros, embora alguns estudos tenham demonstrado uma grande diversidade nos hábitos alimentares. Este trabalho foi realizado em caráter investigativo, com o objetivo de comparar o efeito de dietas na reprodução de calopsitas, assim como efetuar um levantamento dos parâmetros reprodutivos da espécie. O experimento foi feito na Universidade Federal de Lavras. As análises estatísticas foram realizadas utilizando-se o GLM do SAS (Statistical Analysis System, Cary, NC, USA). A variável ordem de postura apresentou significância (P

Foram utilizados 24 suínos machos castrados com o objetivo de determinar o efeito da temperatura ambiente sobre suas respostas termorreguladoras durante o estresse agudo por calor durante 48 horas. Os animais foram alojados em duas câmaras climatizadas com controle de temperatura, umidade e ventilação. Em uma das câmaras, os animais estavam em conforto térmico para a categoria (22ºC) e em outra, em estresse por calor (34ºC). Em cada câmara foram alojados 12 suínos, sendo a parcela experimental representada por dois animais na baia, totalizando seis repetições. As condições ambientais das câmaras climáticas e os parâmetros fisiológicos de frequência respiratória, temperatura retal e superficial foram monitoradas no início e a cada 12 horas durante o período experimental. No período observado, suínos em crescimento apresentaram respostas termorregulatórias efetivas a partir de 12 horas de exposição ao estresse agudo de calor (34°C).

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.

This study aimed to verify the effects of heat stress and dietary energy level on dry matter intake (DMI), water intake, total and partial ruminal and intestinal digestibilities, ruminal characteristics, physiological and digestive behavioral parameters in beef cattle. Six ruminally cannulated Nellore heifers (280 ± 12 kg) were used in a 6 × 6 Latin square experiment with six treatments and six periods of 21 days. The treatments consisted of a 2 × 2 + 2 factorial arrangement, with two temperatures during the day (thermoneutrality, TN: 24°C; and heat stress, HS: 34°C), two dietary energy levels (low- or high-energy concentration) and two additional treatments of animals maintained in TN conditions but pair-fed with the heifers in HS (PFTN). The HS decreased DM intake by about 16% and increase water intake by 25.5% respectively (P ≤ 0.01). Heifers maintained in TN and fed high-energy diet showed 17.3 and 14.3% greater ruminal dry matter (DM) and organic matter (OM) digestibilities compared to their HS counterparts. The DM intake rate (ki, h−1) and digestion rates (kd, h−1) were affected by environment and dietary energy level (P ≤ 0.01), which heifers in HS having lower ki and kd. Heifers in HS presented lower pH and greater ruminal temperature values (P ≤ 0.01). When PFTN treatments were compared vs. HS, there was a significant effect of temperature on acetic acid. Heifers that underwent HS showed 14 % less acetic acid. The ocular temperature, body temperature, heart rate, and respiratory rate were greater in HS heifers (P ≤ 0.01) than in TN. Heifers with low energy level diets showed 33% greater values of rumination time (P = 0.05) when compared to high energy levels independent of the temperatures. We concluded that adaptive response to heat seems important factors responsible for the alteration of DMI, water, and other nutritional fractions like OM, CP, and energy intake. On the other hand, increments in intestinal digestibility in zebu heifers suggest an adaptive response of the digestive tract to heat stress conditions.

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.

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 > 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.

Made available in DSpace on 2022-04-28T19:28:06Z (GMT). No. of bitstreams: 0 Previous issue date: 2020-03-01 Different fat ingredients and their fatty acids may influence the expression of genes responsible to encode enzymes and proteins linked to adipose tissue deposition, influencing beef quality. Therefore, the objective was to analyze the expression of PPARA, SREBF1 and genes involved in lipid metabolism in longissimus thoracis (LT) muscle of cattle fed diets containing soybean or cottonseed with or without vitamin E. Twenty-eight bulls were used in a completely randomized design using a 2 × 2 factorial arrangement. The inclusion of soybean and cottonseed in the diets provided 64.8 g kg−1 and 65.6 g kg−1 of ether extract, respectively, and vitamin E supplementation was 2500 IU per day. The PPARA expression was greater and SREBF1 expression was lower in the muscle of animals fed soybean (P

Objective: Twenty-four pregnant Nellore primiparous grazing cows were used to evaluate the effects of energy-protein supplementation and supplementation frequency during pre (105 d before calving) and postpartum (105 d after calving) on performance and metabolic characteristics.Methods: Experimental treatments consisted of a control (no supplementation), daily supplementation (1.5 kg/d of concentrate/animal) and infrequent supplementation (4.5 kg of concentrate/animal every three days). During the pre and postpartum periods, concentrations of blood metabolites and animal performance were evaluated. Ureagenesis and energy metabolism markers were evaluated at prepartum period.Results: Supplementation frequency did not alter (p>0.10) body weight (BW), average daily gain (ADG), and carcass traits during pre and postpartum. The BW (p = 0.079), adjusted BW at day of parturition (p = 0.078), and ADG (p = 0.074) were greater for supplemented cows during the prepartum. The body condition score (BCS; p = 0.251), and carcass traits (p>0.10) were not affected by supplementation during prepartum. On postpartum, supplementation did not affect animal performance and carcass traits (p>0.10). The dry mater intake was not affected (p>0.10) by supplementation and supplementation frequency throughout the experimental period. Daily supplemented animals had greater (p0.10) the levels of blood metabolites, neither the abundance of ureagenesis nor energy metabolism markers.Conclusion: In summary, our data show that the reduction of supplementation frequency does not cause negative impacts on performance and metabolic characteristics of primiparous grazing cows during the prepartum.

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

The present study aimed to investigate metabolic and physiological changes induced by pregnancy, as well as the expression of key genes linked to the absorptive and proliferative activity of the ruminal epithelium towards the end of the gestational period in zebu beef heifers. Twelve ruminally cannulated Zebu beef heifers were randomly assigned into two experimental treatments: a pregnant group (n = 7) and a control group (non-pregnant; n = 5). All heifers received the same diet throughout the experiment. Respiratory and heart rates and plasma glucose levels were assessed just before and four hours after morning feeding at 110, 171, 206, 242, 266, and 286 days of pregnancy (DOP). Blood samples were collected for serum non-esterified fatty acids (NEFA), beta-hydroxybutyrate (BHB), and urea analysis prior to the morning feedings at 110, 206, 266, and 286 DOP. At 215 and 272 DOP the ruminal epithelium was biopsied to evaluate the mRNA expression of key genes involved in remodeling, inflammation, and transport. The respiratory rate was similar (P ≥ 0.79) between groups over days. However, the heart rate increased (P = 0.01) in late-pregnant heifers compared to controls. Blood concentrations of NEFA (P = 0.11) and BHB (P = 0.67) did not vary over the gestation period in pregnant heifers. Glucose concentrations, before morning feeding, were similar during all collection periods with an exception at 286 days (DOP × physiological status interaction; P = 0.05) when glucose was lower in pregnant (83 mg/dL) compared to non-pregnant (107 mg/dL) heifers. The mRNA expression of genes related to cellular remodeling (PCNA and CASP3), inflammation (KLK9 and KLK10), and transport of volatile fatty acids (SLC16A1 and SLC16A3), H+ (SLC9A1), HCO3− (SLC26A3 and SLC26A6), and glucose (SLC5A1) in the ruminal epithelium were downregulated at late gestation. These results suggest that the ruminal epithelium saves energy at late pregnancy to benefit fetal development. In addition, the increase in heart rate coupled with tissue mobilization can be considered homeorhetic mechanisms that help meet fetal nutrient requirements.

We investigated how feed restriction at 50% of maintenance requirements during different stages of gestation affects the transcriptome of newborn goats' skeletal muscle. Fourteen pregnant dams were randomly assigned into one of the following 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, samples of offspring's Longissimus muscle were collected for total RNA extraction and sequencing. Our data showed 66 differentially expressed (DE) genes (FDR < 0.05). A total of 6 genes were upregulated and 60 downregulated (FDR < 0.05) in the skeletal muscle of the newborns resulting from treatment RM compared with MR. Our results suggest that the DE genes upregulated in newborn goats' skeletal muscle from the RM group compared to MR, included genes related to satellite cells, and genes that indicates impaired insulin sensitivity and changes in the composition of intramuscular fat. The DE genes upregulated in newborn goats' skeletal muscle from the MR group compared to RM, are also related to impaired insulin sensitivity, as well as a predominantly oxidative metabolism and cellular oxidative stress. However, protective mechanisms against insulin sensitivity and oxidative stress may have been augmented in the skeletal muscle of offspring from MR treatment compared to RM, in order to maintain cellular homeostasis.

SUMMARY The objective of this study was to evaluate the effect of probiotic consortium on feed intake, feeding behavior, feed efficiency, fecal score, weight gain and carcass traits in finishing Nellore heifers fed high energy diets in feedlot. Twenty-four Nellore heifers were distributed in 12 pens with two animals each, being six pens per treatment. In the control treatment (CON) the animals were fed exclusively with the base diet, which contained 35% corn silage and 65% concentrate. In the treatment with probiotic consortium technology (TCP), the animals received the base diet and a single dose of 75 mL/animal/day of Bio Ciclo Completo (Global Saúde Brasil) top-dressed in the morning feeding. There was no period of adaptation to the diet. The experiment lasted 93 days. The use of TCP did not affect (P = 0.980) the dry matter intake. The average daily gain was 12.5% greater (P = 0.025) in the animals treated with TCP (0.941 kg/day for TCP versus 0.834 kg/day for CON). The animals that received TCP improved (P = 0.021) the feed efficiency by 12.6%. The animals that received TCP tended to have a better (P = 0.094) fecal score within the first 27 days of feedlot. There were no significant effects of TCP on the feeding behavior and carcass traits. Based on the results, there is a great potential of using TCP to improve productivity in beef cattle.

The present review will present the recent published results and discuss the main effects of nutrients, mainly fatty acids, on the expression of genes involved in lipid metabolism. In this sense, the review focuses in two phases: prenatal life and finishing phase, showing how nutrients can modulate gene expression affecting marbling and fatty acid profile in meat from ruminants. Adiposity in ruminants starts to be affected by nutrients during prenatal life when maternal nutrition affects the differentiation and proliferation of adipose cells enhancing the marbling potential. Therefore, several fetal programming studies were carried out in the last two decades in order to better understand how nutrients affect long-term expression of genes involved in adipogenesis and lipogenesis. In addition, during the finishing phase, marbling becomes largely dependent on starch digestion and glucose metabolism, being important to create alternatives to increase these metabolic processes, and modulates gene expression. Different lipid sources and their fatty acids may also influence the expression of genes responsible to encode enzymes involved in fat tissue deposition, influencing meat quality. In conclusion, the knowledge shows that gene expression is a metabolic factor affecting marbling and fatty acid profile in ruminant meat and diets and their nutrients have direct effect on how these genes are expressed.

Current study evaluated the inclusion of protected fat and different levels of crude protein (CP) in the diet of crossbreed cows in early lactation. Twelve cows were distributed in a 4 x 4 factorial design, with four treatments (12 or 16% CP, with or without MEGALAC-E(r)). Statistical analyzes with ANOVA and Pearson's linear correlation procedures were performed. Protected fat did not affect intake of dry matter (DM) and organic matter (OM) (p > 0.05). Increased CP raised consumption of CP and EE and decreased the non-fiber carbohydrates (NFC; p 0.05) on milk yield and composition due to protected fat or CP rates. Since the inclusion of protected fat and higher content of CP (16%) in the diet did not benefit the production and composition of milk in crossbreed cows, diets with 12% CP without the inclusion of protected fat are recommended. RESUMO. O objetivo desse estudo foi avaliar a inclusão de gordura protegida e de diferentes níveis de PB, na dieta para vacas mestiças, no início da lactação. Foram utilizadas 12 vacas, distribuídas em quadrados latinos 4 x 4 e quatro tratamentos (12 ou 16% de PB, com ou sem MEGALAC-E(r)). Análises estatísticas foram realizadas utilizando Anova e correlações lineares de Pearson. A gordura protegida não influenciou o consumo de MS e MO (p > 0,05). O aumento de PB elevou o consumo de PB e EE e diminuiu o de carboidratos não fibrosos (CNF; P 0,05) na produção e composição do leite em função da gordura protegida ou do teor de PB. A inclusão de gordura protegida e o maior teor de PB (16%) na dieta não resultaram em benefícios na produção e composição do leite de vacas mestiças, portanto recomenda-se utilizar dietas contendo 12% de PB, sem a inclusão de gordura protegida.

To determine the effects of maternal nutrition on modifications of foetal development of the skeletal muscle and possible increase in the potential of skeletal muscle growth in cattle, gestating cows were either fed 190% NRC recommendations (overnourished; ON) or 100% NRC recommendation (control; CO). Interaction between maternal nutrition (MN) and the foetal sex (FS) was also investigated. Foetuses were necropsied at four different time points throughout gestation (139, 199, 241 and 268 days of gestation) to assess the mRNA expression of myogenic, adipogenic and fibrogenic markers in skeletal muscle. Phenotypic indicators of the development of skeletal muscle fibres, intramuscular lipogenesis and collagen development were also evaluated. Modifications in mRNA expression of skeletal muscle of foetuses were observed in function of MN and FS despite the lack of effect of MN and FS on foetal weight at necropsy. Maternal ON increased the mRNA expression of the myogenic marker Cadherin-associated protein, beta 1 (CTNNB1) and adipogenic markers Peroxissome proliferator-activated receptor gamma (PPARG) and Zinc finger protein 423 (ZNF423) at midgestation. However, no differences on foetal skeletal muscle development were observed between treatments at late gestation indicating that a compensatory development may have occurred on CO foetuses making the effect of MN on skeletal muscle development not significant at late gestation. Moreover, our data have shown an evidence of sexual dimorphism during foetal stage with a greater skeletal muscle development in male than in female foetuses. In conclusion, providing a higher nutritional level to pregnant cows changes the trajectory of the development of skeletal muscle during midgestation, but apparently does not change the potential of post-natal growth of muscle mass of the offspring, as no differences in skeletal muscle development were observed in late gestation.

The appropriate supply of nutrients in pregnant cows has been associated with the optimal development of foetal tissues, performance of their progeny and their meat quality. The aim of this study was to evaluate supplementation effects of grazing cows in different stages of gestation on skeletal muscle development and performance of the progeny. Thereby, 27 Nellore cows were divided into three groups (n=9 for each group) and their progeny as follows: UNS, unsupplemented during gestation; MID, supplemented from 30 to 180 days of gestation; LATE, supplemented from 181 to 281 days of gestation. The percentage composition of the supplement provided for the matrices was the following: ground corn (26.25%), wheat bran (26.25%) and soya bean meal (47.5%). The supplement was formulated to contain 30% CP. Supplemented matrices received 150 kg of supplement (1 and 1.5 kg/day for cows in the MID and LATE groups, respectively). After birth, a biopsy was performed to obtain samples of skeletal muscle tissue from calves to determine number and size of muscle fibres and for messenger RNA (mRNA) expression analysis. The percentage composition of the supplement provided for the progeny was the following: ground corn grain (30%), wheat bran (30%), soya bean meal (35%) and molasses (5%). The supplement was formulated to contain 25% CP and offered in an amount of 6 g/kg BW. Performance of the progeny was monitored throughout the suckling period. Means were submitted to ANOVA and regression, and UNS, MID and LATE periods of supplementation were compared. Differences were considered at P0.10). Similarly, no differences were observed between calves for nutrient intake (P>0.10). However, greater subcutaneous fat thickness (P=0.006) was observed in the calves of LATE group. The ribeye area (P=0.077) was greater in calves born from supplemented compared with UNS cows. The supplementation of pregnant cows did not affect the muscle fibre size of their progeny (P=0.208). On the other hand, calves born from dams supplemented at mid-gestation had greater muscle fibre number (P=0.093) compared with calves from UNS group. Greater mRNA expression of peroxysome proliferator-activated receptor α (P=0.073) and fibroblast growth factor 2 (P=0.003) was observed in the calves born from MID cows. Although strategic supplementation did not affect the BW of offspring, it did cause changes in carcass traits, number of myofibres, and mRNA expression of a muscle hypertrophy and lipid oxidation markers in skeletal muscle of the offspring.

Effects of replacement of soybean meal by wet or dry castor bean meal (CM) in diets of feedlot lambs on animal performance, carcass traits, intake, digestibility and hepatic function were assessed. Thirty-five mixed-breed woolless lambs averaging 20±0.26 kg body weight were randomly assigned into five treatments in a 2×2+1 factorial design with 7 animals per treatment. Control animals were fed a diet containing soybean meal while lambs from the remaining groups received diets with 50 or 100% level by dry (DCM) or wet (WCM) calcium hydroxide treated CM as a replacement of soybean meal. Lambs were fed for 70 days and slaughtered at the end of the trial for further carcass traits evaluation. Dry matter intake and digestibility, final body weight, average daily gain and carcass weights were not affected ( P >0.05) by the substitution of soybean meal by either CM source. Serum levels of aspartate aminotransferase and alanine aminotransferase enzymes did not differ among treatments ( P >0.05) indicating no effect of treated CM on hepatic function. These results suggest that castor bean meal treated with calcium hydroxide solution (60 g/kg) can totally replace the soybean meal (up to 18% of dry matter of diet) in the diet of finishing lambs without negative effects on weight gain, intake, digestibility and hepatic function. Castor bean meal treated with calcium hydroxide solution can be fed to animals after 18 h in room temperature, in wet form, without sun or oven-drying.

The objective of this work was to use a meta-analytical approach to evaluate the regulation of voluntary intake in cattle fed tropical forage-based diets using dietary digestibility and bulkiness. Treatment mean values were collected from 53 studies with lactating dairy cows and 126 studies with feedlot growing and finishing cattle that were published in Brazil from 1990 to 2012. In all studies animals were fed ad libitum with diets based on tropical forages. The dataset was analyzed according to meta-analysis techniques, using linear and nonlinear mixed models. The main independent variables were the D-value and the B-value of the diets. The D-value corresponds to the dietary content of digested OM and is associated with energy content of the diet. The B-value is defined as the undigested fraction of NDF and indicates bulkiness of the diet. The DMI presented significant associations with both D-value and B-value. In the first case, DMI intake responded quadratically to the D-value (P = 0.042). On the other hand, DMI decreased linearly as the B-value of the diet increased (P = 0.004). Two new variables called Di and Bi were created to express the intake in terms of D-value and B-value units. A conceptual explicative model was developed from Di and Bi. This model showed that DMI is simultaneously regulated by both physical constraints and metabolic feedbacks. There were differences in the intake pattern of lactating cows and growing cattle.

Twenty-four pregnant Nellore cows were randomly assigned into 2 feeding level groups (control [CTL]; fed 1.0 times the maintenance requirement; n = 12; and overnourished [ON]; fed at 1.5 times the maintenance requirement; n = 12) to evaluate effects of maternal overnutrition on fetal skeletal muscle development. Cows were slaughtered at 135, 190, and 240 d of gestation and samples of fetal LM were collected for analysis of mRNA expression analysis and for histological evaluation of collagen content and number of muscle cells. There was no interaction between gestational period and maternal nutrition for the variables evaluated (P > 0.05). The mRNA expression of Cadherin-associated protein, β 1 (β-catenin) tended to be greater in fetuses from ON cows (P = 0.08), while myogenic differentiation 1 (MyoD; P = 0.56), myogenin (MyoG; P = 0.70), and the number of muscle cells (P = 0.90) were not affected by maternal overnutrition. Gestational period did not affect the mRNA expression of β-catenin (P = 0.60) and MyoG (P = 0.21). The mRNA expression of MyoD tended to increase with days of gestation (P = 0.06). The mRNA expression of zinc finger protein 423 (Zfp423; P < 0.0001), C/EBPα (P = 0.01), and PPARγ (P < 0.0001) were enhanced in ON fetuses. No effects of days of gestation were observed for mRNA expression of Zfp423 (P = 0.75) and C/EBPα (P = 0.48). The mRNA expression of PPARγ in fetuses at 190 d of gestation tended to be greater than those at 135 and 240 d of gestation (P = 0.06). The mRNA expression of transforming growth factor β (TGF-β; P < 0.0001), collagen type III, α I (COL3A1; P < 0.0001), and collagen content (P = 0.01) were increased in ON fetuses. Gestational period did not affect the mRNA expression of collagen type I, α I (COL1A1; P = 0.65). The mRNA expression of COL3A1 (P = 0.09) in fetuses at 190 d of gestation tended to be greater than fetuses at 135 and 240 d of gestation. The mRNA expression of TGF-β in fetuses at 190 d of gestation was greater than in fetuses at 135 d of gestation (P = 0.03), and the values observed in fetuses at 240 d of gestation did not differ from the other gestational time points. The least value of collagen content (P = 0.01) was observed in fetuses at 135 d of gestation, and no differences were observed among the other gestational time points. These data shows that maternal overnutrition enhances fibrogenesis and likely adipogenesis without compromising myogenesis in fetal skeletal muscle of cattle.

This study was developed aiming to evaluate the effects of maternal feed-restriction ond evelopment of gastrointestinal tract (GIT) of bovine fetus at different gestational stages. Feed-restricted cows were fed 1.2 times the maintenance level while the control group was fed ad libitum. Pregnant cows were slaughtered at 136, 189, 239, and 269 days of gestation and gastrointestinal tracts of the fetuses were evaluated. No effects of maternal nutrition on body weight (P 1⁄4 0.17) and body length (P 1⁄40.13) of the fetuses were observed. No major effects of feed restriction on GIT mass of the fetuses were observed (P 1⁄4 0.51). However, the weight of small intestine per unit of body weight was 11.24% greater (P 1⁄40.04) in fetuses from restricted dams. Additionally, the length of small intestine and its villi were 12.93% and 16.44% respectively greater (P o .001) in fetuses from restricted dams compared to those from non-restricted dams. These data indicates that maternal feed-restriction does not affect the development of most of fetal gastrointestinal parts besides small intestine which in turn increases its surface area as a response of maternal feed restriction.

The objective of this study was to evaluate low and high Brix diets, treated or not with 5 g of calcium oxide per kg of natural matter, and corn silage on intake, digestibility and performance of beef cattle. Forty cattle with initial body weight (BW) of 350 kg were used: five composed the control group, 30 were distributed into random blocks (control) and the other five were distributed in a 5 × 5 incomplete Latin square, with the objective of determining digestibility. The 30 animals evaluated for performance were slaughtered and empty body weight (EPW), carcass dressing and meat cuts were determined. The diet with corn silage (CS) presented the best intake of the other ingredients and the best weight gain, except for neutral detergent fiber intake in g/kg of BW. Only carcass dressing, in relation to BW and EBW, was not affected by the treatments, and the others were greater for animals fed diets with sugar cane silage. Animals fed diets with high brix sugar cane silage and treated high brix sugar cane silage presented lower intake of indigestible neutral detergent fiber and neutral detergent fiber corrected for ash and protein (g/kg of BW) in relation to diets with low and high brix sugar cane silage, respectively. Animals fed diets with corn silage presented higher digestibility, except for crude protein and non-fibrous carbohydrates. Animals subjected to diets with corn silage presented low excretion of nitrogen compounds and higher microbial crude protein synthesis. Animals fed sugar cane silage present greater intake, performance and digestibility. The use of lime during 15 or 20o Brix sugar cane ensilage does not alter intake, digestibility or performance of beef cattle.

The second half of beef cows gestation in tropical areas usually occurs during the drought season, where pastures are low in CP. The objective was to evaluate the effects of CP supplementation during the last third of gestation on beef cows weight variation and indicators of nutrient uptake and skeletal muscle mobilization. Forty-three pregnant (gestating males) Nellore cows (543 ± 66 kg) were divided into 8 paddocks (5–6 cows per paddock) of Urochloa decumbens pasture. Four paddocks were supplemented daily with 2 g/kg of a 43.5% CP supplement (SUP, n = 4) and four received only a mineral supplement (CON, n = 4). Treatments started 90 days before the predicted calving date. Liver and Longissimus muscle biopsies for relative mRNA expression and circulating plasma levels of AA were taken at 270 days of gestation. Data were analyzed using MIXED procedure of SAS considering dietary treatment as fixed effect. Differences were declared at P < 0.10. Supplemented cows had greater weight at calving (P = 0.065) and lost less maternal tissues (without considering gestation-related compounds) (P = 0.052) but the calf birth weight was not affected (P = 0.649). Control cows had greater circulating levels of total AA, non-essential AA, glucogenic AA, His, Met, Ala Asn and Ser (P < 0.10) than supplemented cows, probably due to mobilization of skeletal muscle to support liver gluconeogenesis. The expression of mRNA markers for gluconeogenesis in liver was not affected by the supplementation (P > 0.10). Supplemented cows had greater expression of mRNA markers for protein synthesis in muscle (P < 0.10) but not for protein degradation (P > 0.10). In conclusion, CP supplementation for beef cows in late gestation reduces the maternal weight loss probably by giving more substrates for gluconeogenesis and thus reducing the mobilization of AA from maternal skeletal muscle.