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This meta-analysis aims to investigate the effects of residual feed intake (RFI) phenotype on performance, nutrient utilization and meat quality traits in Zebu (Bos indicus) cattle. Twenty-three peer-reviewed publications with 37 treatment means were included in the dataset. Weighted mean difference analysis compared animals categorized into low RFI (more efficient) versus medium or high RFI (less efficient) groups. Data heterogeneity via meta-regression and subgroup analysis, considering variables such as animal age, sex class, experimental duration, RFI group, dietary concentrate, and estimated metabolizable energy intake were also explored. The predominant genetic group of cattle in the dataset was Nellore (89.18%), followed by Brahman (10.81%). More efficient animals (low RFI phenotype) exhibited less dry matter intake (DMI; P < 0.010) than medium or high RFI animals (-0.95 kg vs. -0.42 kg/d). Cattle dietary crude protein and fiber digestibility were consistent across RFI groups (P > 0.05), while dietary ether extract digestibility tended to decrease (P = 0.050) in low RFI animals (-13.20 g/kg DM). Low RFI animals tended to increased (P = 0.065) ribeye area (REA) compared to the high/medium RFI groups, while carcass backfat thickness (BFT) decreased (P = 0.042) compared to high/medium RFI groups. Moreover, there was an increase (P < 0.001) of 0.22 kg in Warner-Bratzler shear force (WBSF) and a reduction (P < 0.001) in the myofibrillar fragmentation index (MFI) in low RFI animals. Meat color parameters (lightness [L*] and yellowness [b*]) and visual marbling scores were consistent (P > 0.05) across RFI groups. In conclusion, Zebu cattle classified as efficient (low RFI) exhibited reduced DMI, which improves their feed efficiency. However, BFT and meat quality parameters such as tenderness (WBSF and MFI) and redness [a*] were compromised by low RFI phenotype, highlighting the challenge of enhancing feed efficiency and meat quality traits in Zebu cattle.

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Two studies evaluated the productive characteristics of young Nellore heifers receiving different days on feed (DOF) to determine the biological slaughter endpoint. In Experiment 1 (Exp. 1), fifty-one Nellore heifers [324 ± 19.3 kg of body weight (BW); 16 ± 1 months] were split into three DOF lengths (45, 75, or 105 days), while in Experiment 2 (Exp. 2), thirty-six Nellore heifers (362 ± 25.5 kg of BW; 18 ± 1 months of age) were split into three DOF lengths (45, 90, or 135 days). In both studies, all animals were distributed in complete randomized blocks according to initial BW and stratified via carcass ultrasound. The diet was supplied ad libitum, allowing 3% of refusals. The point at which the animals achieved 25% of ether extract of shrunk body weight (EESBW) was defined as the biological endpoint. Thus, relationships were made between some characteristics obtained in both studies. Positive linear relationships were found between backfat thickness (BFT) vs. EESBW (p < 0.001, r = 0.84) and BFT vs. body weight (p < 0.001, r = 0.77). Our results suggest that the biological slaughter endpoint for young Nellore heifers is 6.97 mm of backfat thickness or 402 kg shrunk body weight, corresponding to around 75 DOF.

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Understanding the architecture of gene expression is fundamental to unravel the molecular mechanisms regulating complex traits in bovine, such as intramuscular fat content (IMF) and backfat thickness (BFT). These traits are economically important for the beef industry since they affect carcass and meat quality. Our main goal was to identify gene expression regulatory polymorphisms within genomic regions (QTL) associated with IMF and BFT in Nellore cattle. For that, we used RNA-Seq data from 193 Nellore steers to perform SNP calling analysis. Then, we combined the RNA-Seq SNP and a high-density SNP panel to obtain a new dataset for further genome-wide association analysis (GWAS), totaling 534,928 SNPs. GWAS was performed using the Bayes B model. Twenty-one relevant QTL were associated with our target traits. The expression quantitative trait loci (eQTL) analysis was performed using Matrix eQTL with the complete SNP dataset and 12,991 genes, revealing a total of 71,033 cis and 36,497 trans-eQTL (FDR < 0.05). Intersecting with QTL for IMF, we found 231 eQTL regulating the expression levels of 117 genes. Within those eQTL, three predicted deleterious SNPs were identified. We also identified 109 eQTL associated with BFT and affecting the expression of 54 genes. This study revealed genomic regions and regulatory SNPs associated with fat deposition in Nellore cattle. We highlight the transcription factors FOXP4, FOXO3, ZSCAN2, and EBF4, involved in lipid metabolism-related pathways. These results helped us to improve our knowledge about the genetic architecture behind important traits in cattle.

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Backfat is an important trait in pork production, and it has been included in the breeding objectives of genetic companies for decades. Although adipose tissue is a good energy storage, excessive fat results in reduced efficiency and economical losses. A large QTL for backfat thickness on chromosome 5 is still segregating in different commercial pig breeds. We fine mapped this QTL region using a genome-wide association analysis (GWAS) with 133,358 genotyped animals from five commercial populations (Landrace, Pietrain, Large White, Synthetic, and Duroc) imputed to the porcine 660K SNP chip. The lead SNP was located at 5:66103958 (G/A) within the third intron of the CCND2 gene, with the G allele associated with more backfat, while the A allele is associated with less backfat. We further phased the QTL region to discover a core haplotype of five SNPs associated with low backfat across three breeds. Linkage disequilibrium analysis using whole-genome sequence data revealed three candidate causal variants within intronic regions and downstream of the CCND2 gene, including the lead SNP. We evaluated the association of the lead SNP with the expression of the genes in the QTL region (including CCND2) in a large cohort of 100 crossbred samples, sequenced in four different tissues (lung, spleen, liver, muscle). Results show that the A allele increases the expression of CCND2 in an additive way in three out of four tissues. Our findings indicate that the causal variant for this QTL region is a regulatory variant within the third intron of the CCND2 gene affecting the expression of CCND2.

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We aimed to estimate genetic parameters for growth, reproductive, and carcass traits in Tabapuã cattle. Phenotypic data were collected between 1990 and 2019 in 1,218 farms, and the pedigree file had 340,868 animals. The traits evaluated were body weight at 120 (W120), 210 (W210), 365 (W365), and 550 (W550) days of age; age at first calving (AFC), scrotal circumference at 365 days of age (SC365), ribeye area (REA), backfat thickness (BF), and rump fat thickness (RF). The (co)variance components were estimated using the restricted maximum likelihood method, considering single and two-traits animal models. For all traits, the models considered fixed, direct additive genetic, and residual random effects. In addition, for W120 and W210, the maternal additive genetic and maternal permanent environmental effects were also included. Heritabilities for W120, W210, W365, W550, SC365, REA, BF, and RF were of moderate magnitude (0.15, 0.16, 0.23, 0.19, 0.22, 0.36, 0.31, and 0.27, respectively). Low heritability was observed for AFC (0.07). The genetic correlations between growth traits were higher than 0.90, while AFC and SC365 presented negative moderate correlation (−0.66). The REA showed low genetic correlations with BF (0.07) and RF (0.07), whereas BF and RF were highly correlated (0.77). Considering the heritability estimates, selection for AFC would result in limited genetic gain, while for the other traits, it would be satisfactory. Based on the high genetic correlations between growth traits, selection of Tabapuã animals can be performed at younger ages. Additionally, animals can be indirectly selected for AFC through SC365, and only one fat thickness trait may be used in the selection process considering the high genetic correlation and similar heritability values for BF and RF.(AU)

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Performance and carcass traits of finishing pigs fed diets containing different levels of neutral detergent fiber (NDF) and acid detergent fiber (ADF) were evaluated through meta-analysis. The database was constructed using information from 24 papers, 113 treatments, and 2507 animals. Correlation and variance analyze were performed. The weight gain of the pigs showed a negative correlation (P 0.05) by the inclusion of ingredients with high NDF content. Likewise, the inclusion of ingredients with high ADF content did not alter (P > 0.05) feed intake and feed conversion ratio. However, the use of ingredients with a high ADF content reduced (P < 0.05) by 4% the weight gain of the pigs. The use of ingredients with high concentrations of NDF and ADF negatively affect the weight gain and feed conversion of finishing pigs; however, the ADF-related fraction has a positive relationship with the reduction of the backfat thickness.

O desempenho e as características de carcaça de suínos em terminação alimentados com dietas contendo diferentes níveis de fibra em detergente neutro (FDN) e fibra em detergente ácido (FDA) foram avaliados por meio de meta-análise. O banco de dados foi construído com informações de 24 artigos, 113 tratamentos e 2.507 animais. Análises de correlação e variância foram realizadas. O ganho de peso dos suínos apresentou correlação negativa (P 0,05) pela inclusão de ingredientes com alto teor de FDN. Da mesma forma, a inclusão de ingredientes com alto teor de FDA não alterou (P > 0,05) o consumo de ração e a conversão alimentar. Porém, o uso de ingredientes com alto teor de FDA reduziu (P < 0,05) em 4% o ganho de peso dos suínos. O uso de ingredientes com altas concentrações de FDN e FDA afetam negativamente o ganho de peso e conversão alimentar de suínos em terminação, porém fração relacionada a FDA tem relação positiva com a redução da espessura de toucinho.

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Performance and carcass traits of finishing pigs fed diets containing different levels of neutral detergent fiber (NDF) and acid detergent fiber (ADF) were evaluated through meta-analysis. The database was constructed using information from 24 papers, 113 treatments, and 2507 animals. Correlation and variance analyze were performed. The weight gain of the pigs showed a negative correlation (P < 0.01) with the dietary NDF content and with NDF consumption. The feed conversion ratio showed a positive correlation (P < 0.01) with the inclusion of ADF in the test ingredient and with the consumption of NDF and ADF. The backfat thickness showed a negative correlation (P < 0.05) with the NDF content in the diets. The analysis of variance showed that the performance of finishing pigs was not influenced (P > 0.05) by the inclusion of ingredients with high NDF content. Likewise, the inclusion of ingredients with high ADF content did not alter (P > 0.05) feed intake and feed conversion ratio. However, the use of ingredients with a high ADF content reduced (P < 0.05) by 4% the weight gain of the pigs. The use of ingredients with high concentrations of NDF and ADF negatively affect the weight gain and feed conversion of finishing pigs; however, the ADF-related fraction has a positive relationship with the reduction of the backfat thickness.(AU)

O desempenho e as características de carcaça de suínos em terminação alimentados com dietas contendo diferentes níveis de fibra em detergente neutro (FDN) e fibra em detergente ácido (FDA) foram avaliados por meio de meta-análise. O banco de dados foi construído com informações de 24 artigos, 113 tratamentos e 2.507 animais. Análises de correlação e variância foram realizadas. O ganho de peso dos suínos apresentou correlação negativa (P < 0,01) com o teor de FDN da dieta e com o consumo de FDN. A taxa de conversão alimentar apresentou correlação positiva (P < 0,01) com a inclusão de FDA presente nos ingredientes testados e com o consumo de FDN e FDA. A espessura do toucinho apresentou correlação negativa (P < 0,05) com o teor de FDN das dietas. A análise de variância mostrou que o desempenho dos suínos em terminação não foi influenciado (P > 0,05) pela inclusão de ingredientes com alto teor de FDN. Da mesma forma, a inclusão de ingredientes com alto teor de FDA não alterou (P > 0,05) o consumo de ração e a conversão alimentar. Porém, o uso de ingredientes com alto teor de FDA reduziu (P < 0,05) em 4% o ganho de peso dos suínos. O uso de ingredientes com altas concentrações de FDN e FDA afetam negativamente o ganho de peso e conversão alimentar de suínos em terminação, porém fração relacionada a FDA tem relação positiva com a redução da espessura de toucinho.(AU)

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ABSTRACT: Performance and carcass traits of finishing pigs fed diets containing different levels of neutral detergent fiber (NDF) and acid detergent fiber (ADF) were evaluated through meta-analysis. The database was constructed using information from 24 papers, 113 treatments, and 2507 animals. Correlation and variance analyze were performed. The weight gain of the pigs showed a negative correlation (P < 0.01) with the dietary NDF content and with NDF consumption. The feed conversion ratio showed a positive correlation (P < 0.01) with the inclusion of ADF in the test ingredient and with the consumption of NDF and ADF. The backfat thickness showed a negative correlation (P < 0.05) with the NDF content in the diets. The analysis of variance showed that the performance of finishing pigs was not influenced (P > 0.05) by the inclusion of ingredients with high NDF content. Likewise, the inclusion of ingredients with high ADF content did not alter (P > 0.05) feed intake and feed conversion ratio. However, the use of ingredients with a high ADF content reduced (P < 0.05) by 4% the weight gain of the pigs. The use of ingredients with high concentrations of NDF and ADF negatively affect the weight gain and feed conversion of finishing pigs; however, the ADF-related fraction has a positive relationship with the reduction of the backfat thickness.

RESUMO: O desempenho e as características de carcaça de suínos em terminação alimentados com dietas contendo diferentes níveis de fibra em detergente neutro (FDN) e fibra em detergente ácido (FDA) foram avaliados por meio de meta-análise. O banco de dados foi construído com informações de 24 artigos, 113 tratamentos e 2.507 animais. Análises de correlação e variância foram realizadas. O ganho de peso dos suínos apresentou correlação negativa (P < 0,01) com o teor de FDN da dieta e com o consumo de FDN. A taxa de conversão alimentar apresentou correlação positiva (P < 0,01) com a inclusão de FDA presente nos ingredientes testados e com o consumo de FDN e FDA. A espessura do toucinho apresentou correlação negativa (P < 0,05) com o teor de FDN das dietas. A análise de variância mostrou que o desempenho dos suínos em terminação não foi influenciado (P > 0,05) pela inclusão de ingredientes com alto teor de FDN. Da mesma forma, a inclusão de ingredientes com alto teor de FDA não alterou (P > 0,05) o consumo de ração e a conversão alimentar. Porém, o uso de ingredientes com alto teor de FDA reduziu (P < 0,05) em 4% o ganho de peso dos suínos. O uso de ingredientes com altas concentrações de FDN e FDA afetam negativamente o ganho de peso e conversão alimentar de suínos em terminação, porém fração relacionada a FDA tem relação positiva com a redução da espessura de toucinho.

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Improving feed efficiency is a key breeding goal in the beef cattle industry. In this study, we estimated the genetic parameters for feed efficiency and carcass traits in Senepol cattle raised in tropical regions. Various indicators of feed efficiency [gain to feed ratio (G:F), feed conversion ratio (FCR), residual weight gain (RG), residual intake and body weight gain (RIG), and residual feed intake (RFI)] as well as growth [final BW, average daily gain (ADG), and DM intake (DMI)], and carcass [rib-eye area (REA), backfat thickness (BF), intramuscular fat score, and carcass conformation score] traits were included in the study. After data editing, records from 1 393 heifers obtained between 2009 and 2018 were used for the analyses. We fitted an animal model that included contemporary group (animals from the same farm that were evaluated in the same test season) as the fixed effect, and a linear effect of animal age at the beginning of the test as a covariate; in addition to random direct additive genetic and residual effects. The (co)variance components were estimated by Bayesian inference in uni- and bivariate analyses. Our results showed that feed efficiency indicators derived from residual variables such as RG, RIG, and RFI can be improved through genetic selection (h2 = 0.14 ± 0.06, 0.13 ± 0.06, and 0.20 ± 0.08, respectively). Variables calculated as ratios such as G:F and FCR were more influenced by environmental factors (h2 = 0.08 ± 0.05 and 0.09 ± 0.05), and were, therefore, less suitable for use in breeding programs. The traits with the greatest and impact on genetic progress in feed efficiency were ADG, REA, and BF. The traits with the greatest and least impact on growth and carcass traits were RG and RFI, respectively. Selection for feed efficiency will result in distinct overall effects on the growth and carcass traits of Senepol heifers. Direct selection for lower RFI may reduce DMI and increase carcass fatness at the finishing stage, but it might also result in reduced growth and muscle deposition. Residual BW gain is associated with the highest weight gain and zero impact on REA and BF, however, it is linked to higher feed consumption. Thus, the most suitable feed efficiency indicator was RIG, as it promoted the greatest decrease in feed intake concomitant with faster growth, with a similar impact on carcass traits when compared to the other feed efficiency indicators.

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RESUMEN Los consumidores de cerdo demandan productos bajos en grasa y sin aditivos que afecten la salud humana. El objetivo de este trabajo fue evaluar el efecto del cromo-levadura o ractopamina adicionadas a la dieta de cerdos, sobre el rendimiento, las características de la canal y la calidad de la carne. Se distribuyeron 20 cerdos de manera aleatoria en cuatro tratamientos: sin adición de cromo-levadura, ni ractopamina (T1); 10ppm de ractopamina (T2); 0,2ppm de cromo-levadura (T3) y 0,4ppm de cromo- levadura (T4). Se determinó el espesor de la grasa dorsal al inicio, al intermedio y al final del estudio. El rendimiento en canal caliente y fría se estimó en el frigorífico. Muestras de la cabeza del lomo fueron tomadas para evaluar pH, resistencia al corte, goteo, temperatura, retención de agua y contenido de ácidos grasos. Se realizó un análisis descriptivo de los datos y de Kruskal-Wallis, para determinar el efecto del tratamiento sobre las variables medidas. Ninguna suplementación afectó la ganancia de peso, peso final, conversión alimenticia, consumo alimento, rendimiento en canal caliente, rendimiento canal fría y grasa dorsal (P>0,05). La resistencia al corte aumentó con la ractopamina, pero disminuyó con el cromo-levadura. Las pérdidas por goteo fueron significativas con 0,2ppm de cromo-levadura, pero no lo fueron con 0,4ppm de cromo-levadura o ractopamina. No se encontró efecto de la ractopamina sobre los ácidos grasos, pero sí del cromo-levadura. Tanto el cromo-levadura como la ractopamina modifican características de la carne, como la dureza y el perfil de ácidos grasos.

ABSTRACT The consumers of pork demand products low in fat and free of additives that affect the human health. The objective of this study was to evaluate the effect of chromium-yeast or ractopamine added to the diet of pigs on the performance, characteristics of the carcass and meat quality. Twenty pigs were randomized to four treatments: without the addition of chromium-yeast or ractopamine (T1); 10ppm of ractopamine (T2); 0.2ppm of chromium-yeast (T3) and 0.4ppm of chromium-yeast (T4). The backfat thickness was evaluated at the beginning, at the intermediate and at the end of the experiment. Hot carcass yield and cold carcass yield was evaluated in the slaughter house. Loin samples were taken to evaluate pH, shear force, drip loss, temperature, water retention and fatty acid composition. A descriptive analysis of the data and Kruskal-Wallis was carried out to determine the effect of the treatment on the measured variables. Any supplementation affected significantly weight gain, final weight, feed conversion, feed intake, hot carcass yield, cold carcass yield and backfat thinkness (P>0,05). Shear force increased with ractopamine, but decreased with chrome-yeast. Drip losses were significant at 0.2ppm chromium-yeast, but were not significant at 0.4ppm chromium-yeast or ractopamine. There was no effect of ractopamine on fatty acids, but with chromium-yeast was significant. Both chrome-yeast and ractopamine modify meat characteristics such as hardness and fatty acid profile.

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The dietary inclusion of feed additives to improve the carcass characteristics of the final product is of great importance for the pork production chain. The aim of our study was to evaluate the effects of the association of ractopamine (RAC) and conjugated linoleic acid (CLA) on the performance traits of finishing pigs during the last 26 days prior to slaughter. In total, 810 commercial hybrid barrows were used. Animals were distributed among treatments according to a randomised block design in a 3 × 3 factorial arrangement, with three RAC levels (0, 5 or 10 ppm) and three CLA levels (0, 0.3 or 0.6%). Pigs fed the diet with 5 ppm RAC had higher average daily feed intake (ADFI) (2.83 kg; P < 0.05) when compared with those fed 10 ppm RAC and the control diet (2.75 and 2.74 kg, respectively). Lower ADFI values (P < 0.01) were observed with the diets containing CLA compared with the control diet with no CLA (2.73 and 2.75 v. 2.85 kg/day, respectively). The average daily weight gain of pigs fed 5 and 10 ppm RAC was +148 and +173 g/dayhigher (P < 0.001), respectively, than those fed the control diet. Dietary RAC levels influenced (P < 0.001) feed conversion ratio (FCR), which was reduced as RAC levels increased, with the pigs fed 10, 5 and 0 ppm RAC presenting FCR values of 2.57, 2.71 and 3.05, respectively. FCR also improved (P < 0.05) with the inclusion of 0.6% CLA relative to the control diet (2.70 v. 2.84, respectively). There was a significant interaction between CLA × RAC levels (P < 0.01) for final BW, loin eye area (LEA) (P < 0.05) and backfat thickness (BT) (P < 0.05). The treatments containing 10 ppm RAC + 0.6% or 0.3% CLA increased LEA and reduced BT. In conclusion, the level of 10 ppm inclusion of RAC increased the overall performance parameters of pigs and therefore improved production efficiency. The combined use of RAC and CLA promoted a lower feed conversion ratio as well as better quantitative carcass traits, as demonstrated by the higher LEA and lower BT. The dietary inclusion of CLA at 0.3% improved feed efficiency, however, without affecting LEA or BT yields.

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We evaluated whether the procedure for correcting backfat thickness (BT) equation coefficients and lipid mass (LM) initial values in animal profiles, as well as actual model parameter (MP) data and their interrelationships, could reduce errors in predicting body weight (BW) and BT in pigs reared in Southern Brazil. Because different combinations of actual and estimated MP values in advanced system calibration mode (ACM) give rise to distinct calibration procedures, their BT and BW prediction errors were compared with those obtained by INRAPORC® default mode calibration based on different parameter combinations. Correlations among MP were also verified. The BT prediction correction (BTcor) procedure reduced the BT standard deviation of the estimate (σ) from 3.25 to 2.42 mm, but the correction had no effect on BW. Actual BT and feed intake data at 50 kg BW (FI50), reported in ACM, reduced prediction errors of BW and BT, in which their σ values were reduced from 5.29 to <4.08 kg and 2.42 to <2.12 mm, respectively. Mean protein deposition (MeanPD), FI50, and feed intake at 100 kg BW (FI100) were strongly and positively correlated (r>0.98). In addition, initial BW (BWi) was strongly negatively correlated with these parameters (r<­0.87) but positively correlated with the maintenance adjustment factor (MAINT) (r = 0.75). The inclusion of actual or default MP values in the ACM strongly influenced the estimation of other values, as well the predicted outcomes for BW and BT. The BTcor procedure and the input of actual or default MP values into the ACM of INRAPORC® is justified to reduce prediction errors, as it yields considerably greater accuracy in a pig nutritional adjustment system.(AU)

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Crossbreeding represents an important technique to improve growth, beef quality and adaptability in beef production systems in tropical countries. The aim of this study was to evaluate sire and dam breed effects on performance and carcass traits of crossbred cattle produced in a tropical environment. Heifers and steers were evaluated during the pre-weaning, the post-weaning (n = 173) and the finishing phase (n = 123). Animals were produced by mating Nellore (N_N), Angus × Nellore (A_N) and Caracu × Nellore (C_N) dams with Braford, Charbray and Caracu sires. After weaning, animals were raised grazing on Marandu grass for 12 months; thereafter they were housed in individual pens and finished in a feedlot, receiving a total mixed ration. Ultrasound carcass evaluations were performed to determine ribeye area (R_A), backfat thickness (B_T) and rump fat thickness (R_T). A_N progeny were heavier at birth than N_N (P < 0.05), and Braford progeny had greater birth BW than Caracu (P < 0.05). Greater weaning BW was observed in the A_N and C_N offspring compared to N_N (P < 0.01). Greater average daily gain during the post-weaning period was verified in the N_N progeny compared to C_N (P < 0.05). No dam or sire breed effects were observed for BW at the end of the post-weaning period (P > 0.05). Progeny of N_N cows had greater B_T (P < 0.05) and R_T (P < 0.01) at the end of the post-weaning period in relation to C_N. Greater R_A was observed in the Caracu progeny than in the Braford (P < 0.05), which showed greater R_T than the Charbray progeny at the end of the post-weaning period (P < 0.05). No dam or sire breed effects were verified for final BW at the feedlot or for feed efficiency traits (P > 0.05). A_N progeny were superior in final B_T compared to C_N (P < 0.01), and Braford progeny had greater R_T at the end of finishing than Charbray (P = 0.05). The use of crossbred dams allows an increase in productivity until weaning, but this is not maintained in the post-weaning and finishing periods. The use of Braford sires produces similar growth performance in the different stages of the production system to those seen with Charbray and Caracu sires but generates animals with higher fat thickness at the end of finishing, which may improve carcass quality and commercial value.

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BACKGROUND: Positively correlated with carcass weight and animal growth, the ribeye area (REA) and the backfat thickness (BFT) are economic important carcass traits, which impact directly on producer's payment. The selection of these traits has not been satisfactory since they are expressed later in the animal's life and multigene regulated. So, next-generation technologies have been applied in this area to improve animal's selection and better understand the molecular mechanisms involved in the development of these traits. Correlation network analysis, performed by tools like WGCNA (Weighted Correlation Network Analysis), has been used to explore gene-gene interactions and gene-phenotype correlations. Thus, this study aimed to identify putative candidate genes and metabolic pathways that regulate REA and BFT by constructing a gene co-expression network using WGCNA and RNA sequencing data, to better understand genetic and molecular variations behind these complex traits in Nelore cattle. RESULTS: The gene co-expression network analysis, using WGCNA, were built using RNA-sequencing data normalized by transcript per million (TPM) from 43 Nelore steers. Forty-six gene clusters were constructed, between them, three were positively correlated (p-value< 0.1) to the BFT (Green Yellow, Ivory, and Light Yellow modules) and, one cluster was negatively correlated (p-value< 0.1) with REA (Salmon module). The enrichment analysis performed by DAVID and WebGestalt (FDR 5%) identified eight Gene Ontology (GO) terms and three KEGG pathways in the Green Yellow module, mostly associated with immune response and inflammatory mechanisms. The enrichment of the Salmon module demonstrated 19 GO terms and 21 KEGG pathways, related to muscle energy metabolism, lipid metabolism, muscle degradation, and oxidative stress diseases. The Ivory and Light yellow modules have not shown significant results in the enrichment analysis. CONCLUSION: With this study, we verified that inflammation and immune response pathways modulate the BFT trait. Energy and lipid metabolism pathways, highlighting fatty acid metabolism, were the central pathways associated with REA. Some genes, as RSAD2, EIF2AK2, ACAT1, and ACSL1 were considered as putative candidate related to these traits. Altogether these results allow us to a better comprehension of the molecular mechanisms that lead to muscle and fat deposition in bovine.

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The present study investigated the impacts of additional feeding (AF; containing 16% excess feed than control diet in the last two weeks of gestation) during late gestation period and different backfat thickness (BFT) including low (<20 mm) and high (≥20 mm) backfat on reproductive performance, litter size, blood metabolites, hormonal profiles, colostrum, and milk composition of sows from day 90 of gestation to farrowing, and from farrowing to weaning during summer (average 28.3 °C). Fifty-four crossbred sows (Yorkshire × Landrace) were allotted to one of four treatments according to a 2×2 factorial arrangement. There was no AF×BFT interaction for any of the measured variables. The body weight change of sows was decreased for <20 mm in BFT and AF treatments during late gestation and farrowing to weaning periods. The BFT change of sows was higher in AF during late gestation and higher in ≥20 mm BFT during late gestation and farrowing to weaning periods. There were no effects of AF and BFT on the average daily feed intake and weaning-to-oestrus interval; however, sows in AF groups had a greater litter uniformity at birth and initial litter weight. Hormone profiles, colostrum, and milk composition of sows were not different among the treatments. Additional feeding during the last two weeks of gestation increases initial litter size in summer; however, final litter weight is not affected.(AU)

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To compose the experiment, 160 male Topgen pigs - 80 surgically castrated (treatment 1) and 80 immunocastrated (treatment 2) - were randomly selected from a commercial swine farm at the moment of slaughter. Surgical castration was performed when the animals were seven days of age and immunocastration was performed by administering two doses (2 mL each) of immunocastration vaccine (analogue of GnRF linked to a carrier protein, development of anti-GnRF antibodies, 200 mg of a GnRF-protein conjugate/mL) when they were 104 and 132 days of age. Animals from both treatments were maintained in masonry stalls, where they received water and ad libitum diet (the same feed for both groups). The animals were slaughtered at 160 days of age, and the length and width of the testicles of immunocastrated animals were evaluated, along with the degree and number of carcass lesions, carcass traits and meat quality of both treatments. The means of these measurements were calculated and compared by Student´s t-test. For the immunocastrated treatment, Pearson´s correlation coefficients were also calculated for testicle length and width with backfat thickness. Approximately 80% of the immunocastrated animals had testicle widths of 11 cm or less. Immunocastrated animals showed higher degrees of lesions, pH (initial and 8 hours), hue, muscle depth and loin eye area and lower brightness, redness, chroma and backfat thickness than the surgically castrated animals. The correlation between testicle length and width with backfat thickness was inverse. Immunocastration can be an alternative to improve the proportion of lean meat (longissimus thoracis) instead of fat (backfat thickness) leading to better carcass and meat quality, since fat has become undesirable from a nutritional point of view in swine.(AU)

Para compor o experimento, 160 suínos machos (Topgen) - 80 castrados cirurgicamente (tratamento 1) e 80 imunocastrados (tratamento 2) - foram selecionados aleatoriamente de uma granja comercial de suínos no momento do abate. A castração cirúrgica foi realizada quando os animais tinham sete dias de idade e a imunocastração realizada através da administração de duas doses (2 mL cada) da vacina de imunocastração (análogo do GnRH ligado a uma proteína carreadora, desenvolvimento de anticorpos anti-GnRH, 200 mg de um conjugado de proteína GnRH/mL) quando os animais tinham 104 e 132 dias de idade. Os animais de ambos os tratamentos foram mantidos em baias de alvenaria, onde receberam água e ração ad libitum (a mesma dieta para ambos os grupos). Os animais foram abatidos com 160 dias de idade e foram avaliados o comprimento e largura dos testículos dos animais imunocastrados, e o grau e número de lesões na carcaça, características de carcaça e qualidade da carne de ambos os tratamentos. As médias para essas avaliações foram calculadas e comparadas com o teste t. Para o tratamento imunocastrado foi também calculado o coeficiente de correlação de Pearson´s do comprimento e largura dos testículos com a espessura de gordura. Aproximadamente 80% dos animais tiveram largura dos testículos igual ou menor que 11 cm. Os animais imunocastrados mostraram maior grau de lesão, pH (inicial e 8 horas), tonalidade, profundidade de músculo e área de olho de lombo e menor luminosidade, intensidade de vermelho, croma e espessura de gordura do que os animais castrados cirurgicamente. A correlação entre comprimento e largura dos testículos com a espessura de gordura foi negativa. A imunocastração pode ser uma alternativa para aumentar a proporção de carne magra (longissimus thoracis) em detrimento de gordura (espessura de gordura), levando a uma carcaça de melhor qualidade desde que a gordura suína se tornou indesejável do ponto de vista nutricional.(AU)

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The objective of this study was to estimate genetic parameters for carcass and meat quality traits, as well as their genetic correlations using pedigree and genomic information. A total of 3,716; 3,702; 3,439; 3,705; and 3,714 records of 12th-13th rib LM area (LMA), backfat thickness (BF), HCW, marbling score (MARB), and Warner-Bratzler peak shear force (WBSF), respectively, were used. Animals were genotyped with BovineHD BeadChip and GeneSeek Genomic Profiler Indicus HD - GGP75Ki panel. The (co)variance components were estimated by Bayesian inference using a multitrait ssGBLUP analysis. The animal model included fixed effects of contemporary group (defined by the combination of farm and year of birth, and management group at yearling) and age of animal at slaughtering as a covariate (linear). Direct additive genetic and residual effects were fitted as random. The posterior means and SD of heritabilities for LMA, BF, HCW, MARB, and WBSF were 0.28 (0.03), 0.21 (0.04), 0.21 (0.04), 0.12 (0.04), and 0.11 (0.03), respectively. The posterior means for genetic correlations between LMA and meat quality were positive and moderate with MARB (0.38 ± 0.12) and negative with WBSF (-0.47 ± 0.12). Low genetic correlations were estimated between BF and WBSF (-0.03 ± 0.16) and between HCW and MARB (-0.04 ± 0.14), indicating that these traits are not controlled by the same set or linked genes. Carcass traits (LMA, BF, and HCW) presented moderate heritability providing quick response to the selection purpose. The estimates of heritability for meat quality traits (MARB and WBSF) were low and indicate that the rate of genetic improvement for these traits would be slow. Genetic correlations indicated that selection for carcass traits would not be strongly antagonistic for improving meat quality.

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ABSTRACT Twenty-four Iberian castrated male pigs were used to characterize and evaluate the effect of the duration of "Montanera" in the adipocytes size and its relation with the backfat thickness and intramuscular fat. The animals were fed under extensive conditions during 30, 60 and 90 days in the "Dehesa" before slaughtered. Carcass weight, percentage of intramuscular fat, thickness of backfat and its three layers and adipocytes size of the intramuscular fat were obtained. The group which expended 90 days on fattening obtained the highest adipocytes, with an area higher by a 50% than those that only expended 30 days. The differences in diameter and perimeter adipocyte were not as marked as area. A significant positive correlation between the diameter, area and perimeter of adipocyte with the backfat thickness were found. The fat cells in Iberian pig hypertrophy during the "montanera stage", being this increase significant from month to month in this period of fattening. Also, this adipocyte increase is correlated with the animal weight. The correlation between adipocyte size and inner layer of backfat shows that the inner layer obtained in live pig by ultrasound techniques could be a good marker of fat infiltration in pigs fattening in "montanera" system.

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This study was carried out to evaluate the effects of different levels of standardized ileal digestible (SID) methionine + cystine (Met + Cys) and vitamin B6 supplementation on the carcass characteristics and longissimus lumborum (LL) quality in gilts from 75 to 100 kg. Fifty-six gilts were used (Talent x Topigs 20), with an initial average body weight of 75.06 ± 1.68 kg, allotted in a completely randomized block design arranged in a 2×4 factorial scheme, composed of two vitamin B6 supplementation levels (1.58 and 3.58 mg/kg) and four levels of SID Met + Cys (0.370, 0.470, 0.570, and 0.670%), with seven replicates and one animal per experimental unit. No interactions (P > 0.05) between vitamin B6 supplementation and SID Met + Cys levels were observed. The levels of SID Met + Cys and vitamin B6 supplementation did not affect the carcass characteristics. Thawing loss increased linearly, and a quadratic effect was observed for cooking loss and shear force of the LL when dietary SID Met + Cys levels increased. The highest cooking loss (27.29%) and shear force (21.58 N) were estimated at 0.528 and 0.539% SID Met + Cys levels, respectively. The dietary SID Met + Cys requirement for gilts (75100 kg) did not exceed 10.60 g/day (0.37%), based on carcass characteristics and meat quality parameters, and was not affected by vitamin B6 supplementation.

O objetivo foi avaliar os efeitos de níveis de metionina+cistina (Met+Cis) digestíveis e da suplementação de vitamina B6 sobre as características de carcaça e qualidade de carne de fêmeas suínas, dos 75 aos 100 kg. Foram utilizados 56 fêmeas suínas (Talent x Topigs 20), com peso médio inicial de 75,06 ± 1,68 kg; distribuídas em um delineamento experimental de blocos casualizados, num esquema fatorial 2×4, constituído de dois níveis suplementares de vitamina B6 (1,58 e 3,58 mg/kg) e quatro níveis de Met+Cis digestíveis (0,370; 0, 470; 0, 570 e 0, 670%), com sete repetições e um animal por unidade experimental. Não foram observadas interações (P > 0,05) entre suplementação de vitamina B6 e os níveis de Met+Cis digestíveis estudados. Os níveis de Met+Cis digestíveis e a suplementação de vitamina B6 não afetaram as características de carcaça. Foi observado um aumento linear na perda de líquido por descongelamento e uma resposta quadrática para a perda de líquido por cocção e força de cisalhamento em função dos níveis de Met+Cis digestíveis. A maior perda por cocção (27,29%) e força de cisalhamento (21,58 N) foram estimados para os níveis de 0,528 e 0,539%, respectivamente. Conclui-se que a exigência de Met+Cis digestível para fêmeas suínas, dos 75 aos 100 kg, é de no máximo 10,60 g/dia (0,370%), com base nas características de carcaça e nos parâmetros de qualidade de carne, não...

Asunto(s)

RESUMEN

This study was carried out to evaluate the effects of different levels of standardized ileal digestible (SID) methionine + cystine (Met + Cys) and vitamin B6 supplementation on the carcass characteristics and longissimus lumborum (LL) quality in gilts from 75 to 100 kg. Fifty-six gilts were used (Talent x Topigs 20), with an initial average body weight of 75.06 ± 1.68 kg, allotted in a completely randomized block design arranged in a 2×4 factorial scheme, composed of two vitamin B6 supplementation levels (1.58 and 3.58 mg/kg) and four levels of SID Met + Cys (0.370, 0.470, 0.570, and 0.670%), with seven replicates and one animal per experimental unit. No interactions (P > 0.05) between vitamin B6 supplementation and SID Met + Cys levels were observed. The levels of SID Met + Cys and vitamin B6 supplementation did not affect the carcass characteristics. Thawing loss increased linearly, and a quadratic effect was observed for cooking loss and shear force of the LL when dietary SID Met + Cys levels increased. The highest cooking loss (27.29%) and shear force (21.58 N) were estimated at 0.528 and 0.539% SID Met + Cys levels, respectively. The dietary SID Met + Cys requirement for gilts (75100 kg) did not exceed 10.60 g/day (0.37%), based on carcass characteristics and meat quality parameters, and was not affected by vitamin B6 supplementation.(AU)

O objetivo foi avaliar os efeitos de níveis de metionina+cistina (Met+Cis) digestíveis e da suplementação de vitamina B6 sobre as características de carcaça e qualidade de carne de fêmeas suínas, dos 75 aos 100 kg. Foram utilizados 56 fêmeas suínas (Talent x Topigs 20), com peso médio inicial de 75,06 ± 1,68 kg; distribuídas em um delineamento experimental de blocos casualizados, num esquema fatorial 2×4, constituído de dois níveis suplementares de vitamina B6 (1,58 e 3,58 mg/kg) e quatro níveis de Met+Cis digestíveis (0,370; 0, 470; 0, 570 e 0, 670%), com sete repetições e um animal por unidade experimental. Não foram observadas interações (P > 0,05) entre suplementação de vitamina B6 e os níveis de Met+Cis digestíveis estudados. Os níveis de Met+Cis digestíveis e a suplementação de vitamina B6 não afetaram as características de carcaça. Foi observado um aumento linear na perda de líquido por descongelamento e uma resposta quadrática para a perda de líquido por cocção e força de cisalhamento em função dos níveis de Met+Cis digestíveis. A maior perda por cocção (27,29%) e força de cisalhamento (21,58 N) foram estimados para os níveis de 0,528 e 0,539%, respectivamente. Conclui-se que a exigência de Met+Cis digestível para fêmeas suínas, dos 75 aos 100 kg, é de no máximo 10,60 g/dia (0,370%), com base nas características de carcaça e nos parâmetros de qualidade de carne, não...(AU)

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