Strategic administration of an appeasing substance to improve performance and physiological responses of Bos indicus feedlot cattle.

This study was designed to evaluate the timing of administration of the bovine appeasing substance (BAS) on performance and physiological responses of Bos indicus feedlot cattle. Nellore bulls (n = 100) were ranked by initial body weight (BW; 341 ± 18.5 kg) and assigned to receive BAS (n = 50) or placebo (CON; n = 50) on day -2 of the experiment. Treatments (5 mL) were applied topically to the nuchal skin area of each bull. Bulls were loaded into commercial livestock trailers immediately after treatment administration, transported for 880 km, and unloaded on day -1 at a commercial feedyard. On day 0, bulls within each treatment were again assigned to receive, in a 2 × 2 factorial arrangement, BAS or CON as described previously (25 bulls/treatment combination). Upon treatment administration on day 0, bulls were housed in 12 feedlot pens (3 pens/treatment) for a 108-d feeding period, which was divided into an adaptation (days 0-19), growing (days 20-60), and finishing (days 61-108) phases. Dry matter intake (DMI) was measured daily from days 0 to 108, whereas blood samples and hair from the tail switch were collected on days -2, 0, 19, 60, and 108. Administration of BAS prior to loading (day -2) improved ADG, FE, and DMI during adaptation and across the 108-d feeding period (P ≤ 0.08), resulting in greater (P = 0.03) hot carcass weight and dressing percentage upon slaughter on day 109. A treatment × day interaction was detected for serum glucose concentrations (P = 0.05), which was greater (P = 0.03) on day 60 of the feeding period in bulls receiving CON prior to loading. Administration of BAS at feedlot entry (day 0) improved DMI, ADG, and FE during adaptation (P ≤ 0.05), but it did not impact (P ≥ 0.18) performance and carcass traits during the 108-d feeding period. Bulls administered BAS prior to loading and at feedlot entry had less (P ≤ 0.05) mean serum cortisol concentrations across the 108-d feeding period (loading × feedlot entry interaction; P = 0.10) and greater (P ≤ 0.05) serum insulin concentration on day 60 (loading × feedlot entry × day interaction; P = 0.05). In summary, BAS administration prior to loading increased the overall feedlot performance of Nellore bulls. These outcomes were noted in bulls that received or not a second BAS administration at feedlot entry, suggesting that the benefits of BAS are exploited when this substance is administered before transport to the feedlot.

Beef quality of Nellore steers fed dried or rehydrated and ensiled corn or sorghum grains / Calidad de la carne de Ganado Nelore alimentado con grano de maíz o sorgo seco o rehidratado y ensilado / Qualidade de carne de bovinos Nelore alimentados com grãos de milho ou sorgo seco ou reidratado e ensilado

Abstract Background: Rehydration of grains, such as corn and sorghum, is used to increase nutrient absorption. However, the effect of this practice on meat quality is poorly understood. Objective: To evaluate the effects of type of grain and processing on the meat quality of Nellore steers in a feedlot. Methods: Twenty-four non-castrated Nellore steers (270 ± 53 kg initial body weight) were distributed in a completely randomized 2×2 factorial design, with six replicates. The first factor was cereal type (corn or sorghum), and the second was the grain processing (dry or rehydrated and ensiled). The diets were composed of 30% corn silage and 70% concentrate. Sixty days before the beginning of the experiment, corn and sorghum grains were rehydrated and ensiled. The animals were slaughtered after 140 days of confinement. Meat quality analyses were determined in samples of fresh and aged meat (7 days) from the Longissimus lumborum muscle. Results: no difference between treatments was observed for carcass pH and L* (lightness), a* (redness), and b* (yellowness) values, shear force, thawing and cooking losses, and chemical composition of meat (p>0.05). The b* (yellowness) value of subcutaneous fat was higher in steers fed corn, regardless of grain processing (p=0.03). Sarcomere length was higher in aged meat of steers fed sorghum, regardless of processing method (p=0.01). Conclusions: the grain processing method does not affect beef quality; however, grain type can affect subcutaneous fat color and sarcomere length of aged beef.

Resumen Antecedentes: La rehidratación de granos, tales como maíz y sorgo, se usa para aprovechar mejor sus nutrientes. Sin embargo, es poco conocido el efecto de esta práctica sobre la calidad de la carne. Objetivo: Evaluar los efectos del tipo de cereal y su procesamiento sobre la calidad de carne de toretes Nelore en confinamiento. Métodos: Veinticuatro novillos Nelore enteros con un peso promedio inicial de 270 ± 53 kg, se distribuyeron en un diseño factorial 2×2 completamente aleatorizado (n=6). El primer factor fue el tipo de cereal (maíz o sorgo) y el segundo fue su procesamiento (seco o rehidratado y ensilado). Las dietas estuvieron compuestas por 28,44% de ensilaje de maíz y 71,56% de concentrado. Sesenta días antes de iniciar el experimento, los granos de maíz y sorgo se rehidrataron y ensilaron. Los animales se sacrificaron después de 140 días de confinamiento. La calidad de la carne se determinó en muestras de carne fresca y madurada (7 días) obtenidas del músculo Longissimus lumborum. Resultados: No hubo diferencias entre tratamientos para el pH de las canales, ni para los valores de color (L* "luminosidad", a* "intensidad de rojo" y b* "intensidad de amarillo"), fuerza de corte, composición química, o pérdidas de agua por descongelamiento o cocción (p>0,05). El valor de b* de la grasa subcutánea fue mayor en los novillos alimentados con maíz, independientemente del tipo de procesamiento (p=0,03). La longitud de sarcómero fue más alto en la carne madurada de novillos alimentados con sorgo, sin importar el método de procesamiento (p=0,01). Conclusiones: El método de procesamiento del grano no afecta la calidad de la carne; sin embargo, el tipo de cereal afecta el color de la grasa subcutánea y la longitud del sarcómero de la carne madurada.

Resumo Antecedentes: A reidratação de grãos, como milho e sorgo, tem sido usada para aumentar a utilização de seus nutrientes. Contudo, o efeito dessa prática na qualidade da carne é pouco compreendido. Objetivo: Avaliar os efeitos do tipo de grão de cereais e seu processamento sobre a qualidade da carne de bovinos confinados. Métodos: Vinte e quatro bovinos Nelore não castrados, com peso corporal médio inicial de 270 ± 53 kg foram distribuídos em delineamento inteiramente casualizado, fatorial 2×2, com seis repetições. O primeiro fator foi o tipo de grão de cereal no concentrado (milho ou sorgo), e o segundo foi o processamento destes grãos (seco ou reidratado e ensilado). As dietas foram compostas por 28,44% de silagem de milho e 71,56% de concentrado. Sessenta dias antes do início do experimento, os grãos de milho e sorgo foram reidratados e ensilados. Os animais foram abatidos após 140 dias de confinamento. As análises de qualidade da carne foram determinadas em amostras não maturadas e maturadas (7 dias) obtidas do músculo Longissimus lumborum. Resultados: Não houve diferenças significativas (p>0,05) entre os tratamentos para pH da carcaça e L* (luminosidade), a* (intensidade de vermelho), b* (intensidade de amarelo), força de cisalhamento, perdas por descongelamento, perdas por cocção, perdas totais e composição química da carne. O valor de b* da gordura subcutânea foi maior (p=0,03) em bovinos alimentados com dietas contendo grãos de milho, independentemente do tipo de processamento. O comprimento de sarcômero foi maior na carne maturada de novilhos alimentados com sorgo, independente do método de processamento (p=0,01). Conclusões: O método de processamento dos grãos não afetou a qualidade da carne bovina, no entanto, a cor da gordura subcutânea e o comprimento de sarcômero da carne maturada foram afetados pelo tipo de grão.

Proteomic analysis reveals changes in energy metabolism of skeletal muscle in beef cattle supplemented with vitamin A.

BACKGROUND: Vitamin A has been reported as a factor influencing marbling deposition in meat from animals. Although the mechanisms by which vitamin A regulates lipid metabolism in mature adipocytes are already well-established, information regarding molecular mechanisms underlying the effects of vitamin A on the regulation of intramuscular fat deposition in beef cattle still remains limited. The present study aimed to assess the molecular mechanisms involved in the intramuscular fat deposition in beef cattle supplemented with vitamin A during the fattening phase using a proteomic approach. RESULTS: Vitamin A supplementation during the fattening phase decreased intramuscular fat deposition in beef cattle. Proteome and phospho-proteome analysis together with biological and networking analysis of the protein differentially abundant between treatments indicated that Vitamin A supplementation affects the overall energy metabolism of skeletal muscle, impairing lipid biosynthesis in skeletal muscle. CONCLUSION: Vitamin A supplementation at fattening phase impairs intramuscular fat deposition in beef cattle likely by changing the energy metabolism of skeletal muscle. The interaction of retinoic acid and heat shock 70-kDa protein may play a pivotal role in intramuscular fat deposition as a consequence of vitamin A supplementation by impairing de novo fatty acid synthesis as a result of a possible decrease in insulin sensitivity in the skeletal muscle. © 2020 Society of Chemical Industry.

Explaining meat quality of bulls and steers by differential proteome and phosphoproteome analysis of skeletal muscle.

The objective of this study was to evaluate the differential proteome and phosphoproteome between bulls and steers during conversion of muscle to meat, as well as after 14 days of aging. Twelve male Nellore (Bos taurus indicus) calves were used, and six calves were randomly selected for surgical castration. Calves were fed the same diet and were harvested after 230 days on feed. Longissimus muscle was sampled just after stunning (0d postmortem), at deboning (1d postmortem) and after aging (14d postmortem) for differential proteome analysis. Castration upregulated (P < 0.05) the abundance of glycolytic enzymes, while the oxidative phosphorylation protein ATP5B was downregulated (P < 0.05). In addition, abundance of troponin T fast isoform (TNNT3) was upregulated by castration (P < 0.05), while the slow isoform (TNNT1) tended to be decreased (P < 0.10). The creatine kinase M-type was markedly fragmented postmortem. Abundance of phosphorylated PGM1 increased during the first 24 h postmortem and was highly correlated with carcass pH. Further, abundance of the phosphorylated myofibrillar proteins ACTA1 and MYLPF were positively correlated with sarcomere shortening. Overall, our finds demonstrated that abundance and phosphorylation of glycolytic enzymes are associated with changes in beef tenderness and intramuscular fat. SIGNIFICANCE: The design of the present study allowed to clarify the key proteins related to changes during conversion of muscle to meat such as pH decline and sarcomere shortening. In addition, the correlation between some biomarker and meat quality traits were confirmed.

Total nutrient digestibility and small intestine starch digestion in Nellore and Angus young bulls fed a whole shelled corn diet.

Eighteen Nellore and 18 Angus young bulls with BW of 381 ± 12 kg were randomly assigned into two feeding groups (whole shelled corn [WSC] or ground corn with silage [GC]) to evaluate the interaction of breed and diet on total nutrient digestibility, pancreatic α-amylase, and maltase activity and SLC5A1expression in the small intestine. Experimental diets (DM basis) included (a) a diet containing 30% corn silage and 70% GC and soya bean meal-based concentrate and (b) a diet containing 85% WSC and 15% of a soya bean meal- and mineral-based pelleted supplement. The treatments were Nellore fed GC diet; Nellore fed WSC diet; Angus fed GC diet; and Angus fed WSC diet. Total faecal collection for the digestibility trial occurred from day 48 until day 50 of the experimental period. Feeding the WSC diet reduced DM and NDF intake (p < 0.01). Angus had greater DM and nutrient intake in kg/day (p < 0.01). However, there was no breed effect on DM and nutrient intakes based on percentage of BW (p > 0.19). Angus had greater starch digestibility (p = 0.03) than Nellore. Cattle fed the WSC diet had greater DM, NDF and starch digestibility (p < 0.01) compared with those fed the GC diet. The activity of pancreatic α-amylase (U/g of protein) was greater in Nellore (p < 0.01) and was not affected by diet (p = 0.52). In duodenum, maltase activity (U/g of protein) was greater in bulls fed GC diet (p = 0.02). Expression of the gene SLC5A1was not affected by breed or diet (p > 0.05). In conclusion, Nellore had less capacity to digest starch. However, they did not have less pancreatic α-amylase and duodenal maltase activity compared to Angus. The use of the WSC diet increases DM and total nutrient digestibility.

Subspecies and diet affect the expression of genes involved in lipid metabolism and chemical composition of muscle in beef cattle.

Fourteen Nellore and 14 Angus young bulls with BW of 381±11.8kg were randomly assigned into 2 feeding groups (whole shelled corn without forage (WSC) or corn silage and ground corn (GC)) to evaluate chemical composition and expression of genes involved in lipid metabolism in the longissimus thoracis (LT). We hypothesized that bulls fed the WSC diet have greater amounts of intramuscular fat and Angus have higher expression levels of PPAR and SREBF. Meat from Angus bulls had greater ether extract compared to Nellore (P<0.05). Muscle from bulls fed the WSC diet had greater expression of PPARA (P<0.05) and lower levels of SREBF1 expression (P<0.01). The LT of Nellore fed GC had greater expression of FABP4, ACACA and SCD genes (P<0.01). In conclusion, the greater concentration of starch in the WSC diet did not increase marbling in the beef of bulls fed this diet due to the reduced expression of SREBF1.

Effect of post-weaning growth rate on carcass traits and meat quality of Nellore cattle.

This study evaluated the effects of growth rate during post-weaning growing phase on carcass traits and beef quality. Thirty-four Nellore young bulls were randomly assigned to one of three treatments: LOW, MEDIUM or HIGH growth rate during post-weaning growing phase followed by high growth rate in the finishing phase. The growth rate affected (P<0.05) all carcass traits evaluated at the end of post-weaning growing phase, except ultimate pH. Carcass dressing was greatest (P<0.05) for the HIGH growth rate group in both phases. Beef from the HIGH group exhibited the greatest (P<0.05) sarcomere length and a* and b* colour values at the end of post-weaning growing phase. However, post-weaning growth rate did not affected (P>0.05) collagen content and solubility, myofibrillar fragmentation index and Warner-Bratzler shear force. Our data suggest that a low post-weaning growth rate produces lighter and leaner carcasses, but it does not affect meat quality traits in Nellore young bulls.

Molecular Factors Underlying the Deposition of Intramuscular Fat and Collagen in Skeletal Muscle of Nellore and Angus Cattle.

Studies have shown that intramuscular adipogenesis and fibrogenesis may concomitantly occur in skeletal muscle of beef cattle. Thus, we hypothesized that the discrepancy of intramuscular fat content in beef from Nellore and Angus was associated with differences in intramuscular adipogenesis and fibrogenesis during the finishing phase. To test our hypothesis, longissimus muscle samples of Nellore (n = 6; BW = 372.5 ± 37.3 kg) and Angus (n = 6; BW = 382.8 ± 23.9 kg) cattle were collected for analysis of gene and protein expression, and quantification of intramuscular fat and collagen. Least-squares means were estimated for the effect of Breed and differences were considered at P ≤ 0.05. A greater intramuscular fat content was observed in skeletal muscle of Angus compared to Nellore cattle (P≤0.05). No differences were observed for mRNA expression of lipogenic and lipolytic markers ACC, FAS, FABP4, SERBP-1, CPT-2, LPL, and ACOX (P > 0.05) in skeletal muscle of Nellore and Angus cattle. Similarly, no differences were observed in mRNA expression of adipogenic markers Zfp423, PPARγ, and C/EBPα (P>0.05) However, a greater PPARγ protein content was observed in skeletal muscle of Angus compared to Nellore cattle (P≤0.05). A greater abundance of adipo/fibrogenic cells, evaluated by the PDGFRα content, was observed in skeletal muscle of Angus than Nellore cattle (P≤0.05). No differences in fibrogenesis were observed in skeletal muscle of Angus and Nellore cattle, which is in accordance with the lack of differences in intramuscular collagen content in beef from both breeds (P>0.05). These findings demonstrate that difference in intramuscular fat content is associated with a slightly enhanced adipogenesis in skeletal muscle of Angus compared to Nellore cattle, while no difference in fibrogenesis.

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.

Lipids in the diet and the fatty acid profile in beef: a review and recent patents on the topic.

The objective of this review is to report how the use of lipid sources in diets for ruminants can affect the fatty acid profile of beef. In addition, recent patents that can be utilized to alter the fatty acid profile in the meat, or which concern the synthesis of conjugated fatty acids will be reviewed. The industrial production of conjugated linoleic acid (CLA) has already started and the commercial products present isomers cis-9, trans-11; trans-9, cis-11; and trans-10, cis-12. Patents on the biological synthesis of isomer C18:2 cis-9, trans-11 from the linoleic acid have also been published. However, the economic production of CLA in industrial scale is a difficult process. Most of the patents published for CLA production utilize bacteria of the genera Bifidobacterium sp. and Propionibacterium sp. Lipid supplementation, with the objective to improve the fatty acid profile of beef, can be done through the use of patented products, such as genetically modified oilseeds and calcium soaps of fatty acids.