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1.
J Econ Entomol ; 116(6): 2146-2153, 2023 12 11.
Artigo em Inglês | MEDLINE | ID: mdl-37816687

RESUMO

Lepidopteran pests have been successfully managed by the adoption of insect resistant transgenic plants expressing Cry and/or Vip insecticidal proteins derived from Bacillus thuringiensis (Bt plants). Among such pests, Spodoptera frugiperda (Smith, 1797) (Lepidoptera: Noctuidae) is highlighted for its destructive potential in maize crops and for cases of field-evolved resistance to Bt plants. Cry insecticidal proteins expressed in Bt plants are known for their interaction with insect midgut receptors and subsequent midgut cell disruption that leads to target pest death. In the midgut of lepidopteran larval pests such as S. frugiperda, serine proteases are important in dietary protein digestion and activation or degradation of insecticidal proteins. This work was conducted to evaluate if the use of a soybean trypsin inhibitor (SBTI) could disrupt the development of a Bt-susceptible and a Bt-resistant population of S. frugiperda ingesting Bt (expressing Cry1F, Cry1A.105, and Cry2Ab2 Cry proteins) and non-Bt maize plants. The SBTI was produced and purified using recombinant expression in E. coli followed by purification in Ni-Sepharose. Bioassays using non-Bt maize leaves indicated that the development of susceptible and resistant populations of S. frugiperda was not influenced by the ingestion of SBTI. However, when the resistant population consumed Bt maize plants amended with SBTI, high mortality along with a reduction in larval weight and reduced activity of digestive trypsins were observed. Although the mode of action was not elucidated, it is possible that the consumption of SBTI increased susceptibility to Bt maize in the resistant population of S. frugiperda.


Assuntos
Bacillus thuringiensis , Inseticidas , Animais , Spodoptera , Zea mays , Inibidores da Tripsina/farmacologia , Glycine max/genética , Endotoxinas/farmacologia , Escherichia coli/metabolismo , Toxinas de Bacillus thuringiensis , Resistência a Inseticidas , Proteínas de Bactérias/genética , Proteínas de Bactérias/farmacologia , Proteínas Hemolisinas/farmacologia , Proteínas Hemolisinas/genética , Inseticidas/farmacologia , Bacillus thuringiensis/genética , Larva/fisiologia , Plantas Geneticamente Modificadas/genética
2.
PLoS One ; 18(7): e0289003, 2023.
Artigo em Inglês | MEDLINE | ID: mdl-37490504

RESUMO

The genetically modified cotton DAS-21023-5 × DAS-24236-5 × SYN-IR102-7 expressing Cry1Ac, Cry1F and Vip3Aa19 from Bacillus thuringiensis Berliner (Bt) has been cultivated in Brazil since the 2020/2021 season. Here, we assessed the performance of DAS-21023-5 × DAS-24236-5 × SYN-IR102-7 cotton expressing Cry1Ac, Cry1F and Vip3Aa19 against Helicoverpa armigera (Hübner), Helicoverpa zea (Boddie), and their hybrid progeny. We also carried out evaluations with DAS-21023-5 × DAS-24236-5 cotton containing Cry1Ac and Cry1F. In leaf-disk bioassays, DAS-21023-5 × DAS-24236-5 × SYN-IR102-7 was effective in controlling neonates from laboratory colonies of H. armigera, H. zea and the hybrid progeny (71.9%-100% mortality). On floral bud bioassays using L2 larvae, H. zea presented complete mortality, whereas H. armigera and the hybrid progeny showed <55% mortality. On DAS-21023-5 × DAS-24236-5 cotton, the mortality of H. armigera on leaf-disk and floral buds ranged from 60% to 73%, whereas mortality of hybrids was <46%. This Bt cotton caused complete mortality of H. zea larvae from a laboratory colony in the early growth stages, but mortalities were <55% on advanced growth stages and on floral buds. In field studies conducted from 2014 to 2019, DAS-21023-5 × DAS-24236-5 × SYN-IR102-7 cotton was also effective at protecting plants against H. armigera. In contrast, a population of H. zea collected in western Bahia in 2021/2022 on Bt cotton expressing Cry1 and Vip3Aa proteins, showed 63% mortality after 30 d, with insects developing into fifth and sixth instars, on DAS-21023-5 × DAS-24236-5 × SYN-IR102-7 cotton. We conclude that H. armigera, H. zea, and their hybrid progeny can be managed with DAS-21023-5 × DAS-24236-5 × SYN-IR102-7 cotton; however we found the first evidence in Brazil of a significant reduction in the susceptibility to DAS-21023-5 × DAS-24236-5 × SYN-IR102-7 cotton of a population of H. zea collected from Bt cotton in Bahia in 2021/2022.


Assuntos
Inseticidas , Mariposas , Animais , Humanos , Recém-Nascido , Inseticidas/farmacologia , Brasil , Zea mays/genética , Endotoxinas/genética , Proteínas de Bactérias/genética , Proteínas de Bactérias/farmacologia , Toxinas de Bacillus thuringiensis , Proteínas Hemolisinas/genética , Proteínas Hemolisinas/farmacologia , Mariposas/genética , Larva/genética , Gossypium/genética , Plantas Geneticamente Modificadas/genética
3.
J Econ Entomol ; 114(4): 1817-1822, 2021 08 05.
Artigo em Inglês | MEDLINE | ID: mdl-34104964

RESUMO

Like conventional crops, transgenic plants expressing insecticidal toxins from Bacillus thuringiensis (Bt) are subjected to water deprivation. However, the effects of water deprivation over the insecticidal activity of Bt plants are not well understood. We submitted Bt maize and Bt soybean to water deprivation and evaluated biochemical stress markers and the insecticidal activity of plants against target insects. Bt maize (DAS-Ø15Ø7-1 × MON-89Ø34-3 × MON-ØØ6Ø3-6 × SYN-IR162-4) containing the PowerCore Ultra traits, Bt soybean (DAS-444Ø6-6 × DAS-81419-2) with the Conkesta E3 traits, and commercial non-Bt cultivars were cultivated and exposed to water deprivation in the greenhouse. Leaves were harvested for quantification of hydrogen peroxide, malondialdeyde (MDA), and total phenolics and insecticidal activity. Maize or soybean leaf disks were used to evaluate the insecticidal activity against, respectively, Spodoptera frugiperda (J.E Smith) and Chrysodeixis includens (Walker) neonates. Except for Bt soybean, water deprivation increased hydrogen peroxide and MDA contents in Bt and non-Bt plants. Both biochemical markers of water deficit were observed in lower concentrations in Bt plants than in non-Bt commercial cultivars. Water deprivation did not result in changes of phenolic contents in Bt and non-Bt maize. For Bt or non-Bt soybean, phenolic contents were similar despite plants being exposed or not to water deprivation. Water deprivation did not alter substantially insect survival in non-Bt maize or non-Bt soybean. Despite water deprivation-induced biochemical changes in plants, both Bt plants maintained their insecticidal activity (100% mortality) against the target species.


Assuntos
Bacillus thuringiensis , Inseticidas , Animais , Bacillus thuringiensis/genética , Toxinas de Bacillus thuringiensis , Proteínas de Bactérias/genética , Endotoxinas , Proteínas Hemolisinas/genética , Larva , Plantas Geneticamente Modificadas/genética , Glycine max/genética , Spodoptera/genética , Privação de Água , Zea mays/genética
4.
PLoS One ; 16(5): e0251134, 2021.
Artigo em Inglês | MEDLINE | ID: mdl-33945577

RESUMO

The efficacy and non-target arthropod effects of transgenic DAS-21023-5 × DAS-24236-5 × SYN-IR102-7 Bt cotton, expressing proteins Cry1Ac, Cry1F and Vip3Aa19, was examined through field trials in Brazil. Fifteen field efficacy experiments were conducted from 2014 through the 2020 growing season across six different states in Brazil to evaluate performance against key lepidopteran pests through artificial infestations of Chrysodeixis includens (Walker), Spodoptera frugiperda (J.E. Smith,1797), Spodoptera cosmioides (Walker, 1858) and Chloridea virescens (F., 1781), and natural infestations of Alabama argillacea (Hübner) and S. frugiperda. The impact of this Bt cotton technology on the non-target arthropod community in Brazilian cotton production systems was also assessed in a multi-site experiment. DAS-21023-5 × DAS-24236-5 × SYN-IR102-7 cotton significantly reduced the feeding damage caused by S. frugiperda, S. cosmioides, C. includens, C. virescens and A. argillacea, causing high levels of mortality (greater than 99%) to all target lepidopteran pests evaluated during vegetative and/or reproductive stages of crop development. Non-target arthropod community-level analyses confirmed no unintended effects on the arthropod groups monitored. These results demonstrate the value of transgenic Bt cotton containing event DAS-21023-5 × DAS-24236-5 × SYN-IR102-7 for consideration as part of an integrated approach for managing key lepidopteran pests in Brazilian cotton production systems.


Assuntos
Ácido 4-Acetamido-4'-isotiocianatostilbeno-2,2'-dissulfônico/análogos & derivados , Artrópodes/crescimento & desenvolvimento , Gossypium/metabolismo , Gossypium/parasitologia , Ácido 4-Acetamido-4'-isotiocianatostilbeno-2,2'-dissulfônico/metabolismo , Animais , Brasil , Controle de Insetos , Larva/crescimento & desenvolvimento , Mariposas/crescimento & desenvolvimento , Controle Biológico de Vetores/métodos , Folhas de Planta/parasitologia , Plantas Geneticamente Modificadas/parasitologia , Spodoptera/crescimento & desenvolvimento
5.
Postgrad Med ; 132(8): 697-701, 2020 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-33016178

RESUMO

BACKGROUND: Type 2 diabetes mellitus (T2DM) in postmenopausal women is associated with a high incidence of urogenital infections, which negatively impact the quality of life and increase morbidity, mortality, and health-care costs. Glucosuria is a known risk factor for these infections; therefore, it is of interest to determine if increased glucosuria secondary to sodium-glucose cotransporter-2 inhibitors (SGLT2in) impacts the incidence and severity of urogenital infections in postmenopausal women with T2DM. METHODS: The study was conducted at Gaffrée Guinle University Hospital on two groups of postmenopausal women with T2DM: with and without SGLT2in therapy (n = 80 in each group). Medical records and laboratory parameters (urinary dipstick test and culture; blood glucose, glycosylated hemoglobin, and creatinine; cervical cytologic study) of all subjects were carefully assessed at baseline and thrice during the 12-month study period. RESULTS: We observed a significant incidence of vulvovaginitis (relative risk [RR], 2.37; 95% confidence interval [CI], 1.10-5.10; P = 0.03) and asymptomatic bacteriuria (RR, 2.47; 95% CI, 1.09-5.60; P = 0.03), but not of urinary tract infections (RR, 2.08; 95% CI, 0.74-5.81; P = 0.16), secondary to SGLT2in therapy. Genital infection was severe enough to warrant treatment discontinuation in 57.89% of patients in group 1. All urinary tract infections were of mild intensity with a good response to antibiotic therapy. CONCLUSION: Glucosuria induced by SGLT2in therapy may lead to a high incidence of urogenital infections in postmenopausal women with T2DM and can be considered a risk factor for these infections.


Assuntos
Diabetes Mellitus Tipo 2/tratamento farmacológico , Glicosúria/induzido quimicamente , Glicosúria/complicações , Pós-Menopausa , Inibidores do Transportador 2 de Sódio-Glicose/efeitos adversos , Infecções Urinárias/etiologia , Idoso , Antibacterianos/uso terapêutico , Bacteriúria/etiologia , Glicemia , Estudos de Casos e Controles , Creatinina/sangue , Feminino , Hemoglobinas Glicadas , Humanos , Incidência , Estudos Longitudinais , Pessoa de Meia-Idade , Estudos Prospectivos , Fatores de Risco , Índice de Gravidade de Doença , Inibidores do Transportador 2 de Sódio-Glicose/uso terapêutico , Infecções Urinárias/tratamento farmacológico , Vulvovaginite/etiologia
6.
Sci Rep ; 10(1): 10080, 2020 06 22.
Artigo em Inglês | MEDLINE | ID: mdl-32572133

RESUMO

Spodoptera frugiperda is one of the main pests of maize and cotton in Brazil and has increased its occurrence on soybean. Field-evolved resistance of this species to Cry1 Bacillus thuringiensis (Bt) proteins expressed in maize has been characterized in Brazil, Argentina, Puerto Rico and southeastern U.S. Here, we conducted studies to evaluate the survival and development of S. frugiperda strains that are susceptible, selected for resistance to Bt-maize single (Cry1F) or pyramided (Cry1F/Cry1A.105/Cry2Ab2) events and F1 hybrids of the selected and susceptible strains (heterozygotes) on DAS-444Ø6-6 × DAS-81419-2 soybean with tolerance to 2,4-D, glyphosate and ammonium glufosinate herbicides (event DAS-444Ø6-6) and insect-resistant due to expression of Cry1Ac and Cry1F Bt proteins (event DAS-81419-2). Susceptible insects of S. frugiperda did not survive on Cry1Ac/Cry1F-soybean. However, homozygous-resistant and heterozygous insects were able to survive and emerge as fertile adults when fed on Cry1Ac/Cry1F-soybean, suggesting that the resistance is partially recessive. Life history studies revealed that homozygous-resistant insects had similar development, reproductive performance, net reproductive rate, intrinsic and finite rates of population increase on Cry1Ac/Cry1F-soybean and non-Bt soybean. In contrast, heterozygotes had their fertility life table parameters significantly reduced on Cry1Ac/Cry1F-soybean. Therefore, the selection of S. frugiperda for resistance to single and pyramided Bt maize can result in cross-crop resistance to DAS-444Ø6-6 × DAS-81419-2 soybean. The importance of these results to integrated pest management (IPM) and insect resistance management (IRM) programs is discussed.


Assuntos
Toxinas de Bacillus thuringiensis/genética , Endotoxinas/genética , Proteínas Hemolisinas/genética , Spodoptera/metabolismo , Zea mays/genética , Animais , Bacillus thuringiensis/genética , Toxinas de Bacillus thuringiensis/metabolismo , Proteínas de Bactérias/metabolismo , Fenômenos Bioquímicos , Brasil , Resistência à Doença/genética , Endotoxinas/metabolismo , Fabaceae/metabolismo , Hipersensibilidade Alimentar , Proteínas Hemolisinas/metabolismo , Resistência a Inseticidas/genética , Plantas Geneticamente Modificadas/genética , Plantas Geneticamente Modificadas/metabolismo , Glycine max/genética , Glycine max/metabolismo , Spodoptera/imunologia , Spodoptera/patogenicidade
7.
Pest Manag Sci ; 76(12): 4029-4035, 2020 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-32520447

RESUMO

BACKGROUND: Spodoptera eridania (Stoll), S. cosmioides (Walker) and S. albula (Walker) (Lepidoptera: Noctuidae) are considered secondary pests of soybean in South America. The genetically-modified soybean DAS-444Ø6-6 × DAS-81419-2 with tolerance to 2,4-dichlorophenoxyacetic acid (2,4-D), glyphosate and ammonium glufosinate herbicides (event DAS-444Ø6-6) and insect-resistance due to expression of Cry1Ac and Cry1F Bt proteins (event DAS-81419-2) may provide a potential tool for integrated pest management (IPM) of these species in soybean fields. Based on this, we conducted bioassays to evaluate the survival and development of S. eridania, S. cosmioides and S. albula fed on Cry1Ac/Cry1F-soybean leaf tissue. RESULTS: Spodoptera eridania and S. cosmioides fed on Cry1Ac/Cry1F-soybean showed longer developmental time, lower larval and egg to adult survival compared to those fed on non-Bt soybean, reducing the population growth of these species. Spodoptera albula also had lower larval survival and number of insects that reached adulthood on Cry1Ac/Cry1F-soybean. However, no significant effects of Cry1Ac/Cry1F-soybean on population growth parameters were detected in this species. CONCLUSIONS: Soybean with stacked events DAS-444Ø6-6 × DAS-81419-2 expressing Cry1Ac/Cry1F Bt proteins provide population suppression of S. eridania and S. cosmioides. However, this Bt soybean had minimal effects on S. albula, and is unlikely to have negative population-level effects on this species. It is expected that under field conditions, other control tactics must be integrated with Cry1Ac/Cry1F-soybean for the management of these Spodoptera species. © 2020 The Authors. Pest Management Science published by John Wiley & Sons Ltd on behalf of Society of Chemical Industry.


Assuntos
Glycine max , Proteínas Hemolisinas , Animais , Proteínas de Bactérias/genética , Endotoxinas/genética , Proteínas Hemolisinas/genética , Larva , Plantas Geneticamente Modificadas/genética , Glycine max/genética , Spodoptera/genética
8.
Trop Anim Health Prod ; 52(3): 1513-1517, 2020 May.
Artigo em Inglês | MEDLINE | ID: mdl-31838716

RESUMO

The purpose of this study was to estimate parameters related to the population structure and genetic diversity in the Simental breed based on the pedigree information of 77,553 animals. The individual coefficients of inbreeding and average relatedness, number of complete generations, coefficient of change of inbreeding, effective size, effective number of founders, number of ancestors and generation interval were calculated. Using the Simmental cattle information, the mean inbreeding and average relatedness coefficients were 1.49% and 0.99%, respectively. The effective number of founders and ancestors was 163 and 132, respectively, and the effective population size was 48.03. Despite the relatively small inbreeding coefficient, some of the estimated population parameters indicated the need to adopt measures to maintain the genetic variability of the population.


Assuntos
Bovinos/genética , Variação Genética , Linhagem , Animais , Feminino , Endogamia , Masculino
9.
J Econ Entomol ; 112(2): 803-811, 2019 03 21.
Artigo em Inglês | MEDLINE | ID: mdl-30561710

RESUMO

Field studies across four states in maize-producing areas of Brazil were conducted to characterize the efficacy of a new pyramided Bacillus thuringiensis (Bt) Berliner technology in maize, Zea mays L., and compare it to existing single and pyramided commercial Bt technologies, to control Helicoverpa zea Boddie (Lepidoptera: Noctuidae), Elasmopalpus lignosellus Zeller (Lepidoptera: Pyralidae), Agrotis ipsilon (Hufnagel) (Lepidoptera: Noctuidae), and Diatraea saccharalis F. (Lepidoptera: Crambidae). Bt maize expressing Vip3Aa20 protein and pyramided Bt maize expressing proteins Cry1F + Cry1A.105 + Cry2Ab2 + Vip3Aa20 provided excellent protection against kernel feeding by H. zea compared to Bt technologies expressing only Cry1F or Cry1A.105 + Cry2Ab2. Bt maize expressing Cry1F, Cry1A.105 + Cry2Ab2, Cry1F + Cry1A.105 + Cry2Ab2, and Cry1F + Cry1A.105 + Cry2Ab2 + Vip3Aa20 resulted in less than 5% of plants injured by E. lignosellus, significantly less than Bt maize expressing only Vip3Aa20 and a non-Bt maize iso-hybrid with and without a thiamethoxam seed treatment. The highest protection against plant cutting injury caused by A. ipsilon was observed in the pyramid Bt maize technology expressing Cry1F + Cry1A.105 + Cry2Ab2 + Vip3Aa20. However, it did not differ statistically from the Bt maize expressing Vip3Aa20, Cry1F, or Cry1F + Cry1A.105 + Cry2Ab2. All Bt maize hybrids evaluated in our study were highly effective in reducing tunneling injury caused by D. saccharalis. These results show that a new maize technology expressing pyramided Bt proteins Cry1F + Cry1A.105 + Cry2Ab2 + Vip3Aa20 offers a higher level of protection from feeding by the above lepidopteran pest complex compared to maize with a single Bt protein or double pyramided Bt proteins.


Assuntos
Bacillus thuringiensis , Mariposas , Animais , Proteínas de Bactérias , Brasil , Endotoxinas , Proteínas Hemolisinas , Larva , Plantas Geneticamente Modificadas , Zea mays
10.
PLoS One ; 13(2): e0191567, 2018.
Artigo em Inglês | MEDLINE | ID: mdl-29394266

RESUMO

Field-scale studies that examine the potential for adverse effects of Bt crop technology on non-target arthropods may supplement data from laboratory studies to support an environmental risk assessment. A three year field study was conducted in Brazil to evaluate potential for adverse effects of cultivating soybean event DAS-81419-2 that produces the Cry1Ac and Cry1F proteins. To do so, we examined the diversity and abundance of non-target arthropods (NTAs) in Bt soybean in comparison with its non-Bt near isoline, with and without conventional insecticide applications, in three Brazilian soybean producing regions. Non-target arthropod abundance was surveyed using Moericke traps (yellow pan) and pitfall trapping. Total abundance (N), richness (S), Shannon-Wiener (H'), Simpson's (D) and Pielou's evenness (J) values for arthropod samples were calculated for each treatment and sampling period (soybean growth stages). A faunistic analysis was used to select the most representative NTAs which were used to describe the NTA community structure associated with soybean, and to test for effects due to the treatments effects via application of the Principal Response Curve (PRC) method. Across all years and sites, a total of 254,054 individuals from 190 taxa were collected by Moericke traps, while 29,813 individuals from 100 taxa were collected using pitfall traps. Across sites and sampling dates, the abundance and diversity measurements of representative NTAs were not significantly affected by Bt soybean as compared with non-sprayed non-Bt soybean. Similarly, community analyses and repeated measures ANOVA, when applicable, indicated that neither Bt soybean nor insecticide sprays altered the structure of the NTA communities under study. These results support the conclusion that transgenic soybean event DAS-81419-2 producing Cry1Ac and Cry1F toxins does not adversely affect the NTA community associated with soybean.


Assuntos
Artrópodes/efeitos dos fármacos , Proteínas de Bactérias/genética , Endotoxinas/genética , Glycine max/genética , Proteínas Hemolisinas/genética , Plantas Geneticamente Modificadas/genética , Animais , Toxinas de Bacillus thuringiensis , Proteínas de Bactérias/farmacologia , Brasil , Endotoxinas/farmacologia , Proteínas Hemolisinas/farmacologia
11.
Hemodial Int ; 22(3): 405-412, 2018 07.
Artigo em Inglês | MEDLINE | ID: mdl-29227585

RESUMO

INTRODUCTION: Patient who was undergoing hemodialysis (HD) thrice weekly usually gain 1 to 4 kg of weight in interdialytic period, mainly due to fluid accumulation by ingestion of water. Ultrafiltration (UF) during HD will be need to remove fluid excess to avoid severe medical complications secondary to fluid overload. However, in pregnant woman UF can increase the episodes of intradialytic hypotension which may lead to placental ischemic injury and predispose to fetal distress. There is little information about safe fluid amount withdrawn by UF during pregnancy. METHODS: We prospectively study by obstetric Doppler ultrasonography the fluxometric parameters: pulsatility index (PI) and resistance index (RI) of fetal middle cerebral, uterine, and umbilical artery obtained at the beginning and the end of HD session, the acute and chronic effect of UF on placenta and fetus blood flow, as well as the fetal outcome in 1 pregnant woman on chronic HD. FINDINGS: We did not observe any acute harmful effect on fetal middle cerebral, placental and umbilical artery blood flow when UF rate of 2.1 ± 0.04 L (6 < 8 mL/h/kg) during HD session, no significant statistical difference was observed when compared PI and RI before and after UF and also when we compared these data with reference value on normal pregnancy to the same gestational age. DISCUSSION: UF rate of 6 < 8 mL/h/kg during HD did not bring any acute harmful effect on fetal middle cerebral, placental, and umbilical blood flow and the UF rate of 1.4 6 0.4 L (< 6 mL/h/kg) / HD session that was done in all others HD during pregnancy was safe, without any chronic fetal deleterious effect. Obstetric Doppler ultrasonography is a simple and noninvasive method to fetal follow-up and can aid to determine safe UF rate in pregnant women during gestation.


Assuntos
Velocidade do Fluxo Sanguíneo/fisiologia , Sangue Fetal/metabolismo , Diálise Renal/métodos , Ultrafiltração/métodos , Adulto , Doença Crônica , Feminino , Hemodinâmica , Humanos , Gravidez , Estudos Prospectivos
12.
R. Ci. agrovet. ; 17(3): 377-382, 2018. tab
Artigo em Inglês | VETINDEX | ID: vti-738583

RESUMO

Considering the scarcity of information regarding blood parameters of Pêga donkeys (Equus asinus), and the influence of factors such as breed and physiological status on these parameters, this study aimed to evaluate the influence of pregnancy on hematological, blood biochemical and serum protein profiles of the Pêga donkey, using samples from 59 female adult donkeys, 22 pregnant and 37 non-pregnant, kept under field conditions. The parameters measured were counts of red blood cells (RBC), white blood cells (WBC), basophils, eosinophils, bands, segmented neutrophils, lymphocytes, monocytes and platelets; and the levels of packed cell volume, hemoglobin concentration, alanine aminotransferase, aspartate aminotransferase, alkaline phosphatase, creatine kinase, gamma-glutamyl transferase, urea, glucose, cholesterol, triglycerides, total calcium, phosphorus, magnesium, chlorides, sodium, potassium, ionized calcium, creatinine, total protein, albumin, total, direct and indirect serum bilirubin. Serum protein fractionation was performed by sodium dodecyl sulphate-polyacrylamide gel electrophoresis (SDS-PAGE), which found 10 proteins: immunoglobulins A and G, ceruloplasmin, transferrin, albumin, haptoglobin, 1-acid glycoprotein, 138 kDa (MWP138), 33 kDa (MWP33) and 23 kDa (MWP23) molecular weight proteins. RBC and triglycerides were higher in pregnant females. Urea, Immunoglobulin A, MWP138 and MWP23 concentrations were higher in non-pregnant mares. This study presented differences from previous studies, and some differences in blood variables between pregnant and non-pregnant Pêga donkeys, confirming that pregnancy causes significant metabolic changes, which must be considered in the clinical evaluation of these animals.(AU)


Considerando a escassez de informações sobre as variáveis hematológicas dos jumentos Pêga e a influência de fatores como raça e estado fisiológico sobre estes parâmetros, este estudo teve como objetivo avaliar a influência da prenhez sobre os perfis hematológico, bioquímico sanguíneo e de proteínas séricas de jumentos Pêga, utilizando amostras de 59 jumentas adultas, 22 prenhes e 37 não prenhes, mantidas sob condições de campo. Foram mensuradas as contagens de hemácias, leucócitos, basófilos, eosinófilos, neutrófilos bastonetes, neutrófilos segmentados, linfócitos, monócitos e plaquetas; volume globular, concentração de hemoglobina e os níveis de alanina aminotransferase, aspartato aminotransferase, fosfatase alcalina, creatina quinase, gama glutamil transferase, ureia, glicose, colesterol, triglicérides, cálcio total, fósforo, magnésio, cloretos, sódio, potássio, cálcio ionizado, creatinina, proteína total, albumina, bilirrubina total, direta e indireta. O fracionamento de proteínas séricas foi realizado pela eletroforese em gel de acrilamida contendo dodecil sulfato de sódio (SDS-PAGE), o qual revelou 10 proteínas: imunoglobulinas A e G, ceruloplasmina, transferrina, albumina, haptoglobina, 1-glicoproteína ácida, proteína de peso molecular 138 kDa (PPM138), 33 kDa (PPM33) e 23 kDa (PPM23). A contagem de eritrócitos e os triglicérides séricos foram mais altos para as fêmeas prenhes. As concentrações de ureia, IgA, PPM138e PPM23 foram mais altas para jumentas não prenhes. Houve diferenças em relação a estudos anteriores, e diferenças entre as variáveis sanguíneas de jumentas Pêga prenhes e vazias confirmam que a prenhez causa mudanças metabólicas significantes, as quais devem ser consideradas na avaliação clínica destes animais.(AU)


Assuntos
Animais , Feminino , Gravidez , Proteínas Sanguíneas/análise , Equidae/sangue , Padrões de Referência , Testes Hematológicos/veterinária , Eletroforese/veterinária , Contagem de Eritrócitos/veterinária
13.
Rev. Ciênc. Agrovet. (Online) ; 17(3): 377-382, 2018. tab
Artigo em Inglês | VETINDEX | ID: biblio-1488263

RESUMO

Considering the scarcity of information regarding blood parameters of Pêga donkeys (Equus asinus), and the influence of factors such as breed and physiological status on these parameters, this study aimed to evaluate the influence of pregnancy on hematological, blood biochemical and serum protein profiles of the Pêga donkey, using samples from 59 female adult donkeys, 22 pregnant and 37 non-pregnant, kept under field conditions. The parameters measured were counts of red blood cells (RBC), white blood cells (WBC), basophils, eosinophils, bands, segmented neutrophils, lymphocytes, monocytes and platelets; and the levels of packed cell volume, hemoglobin concentration, alanine aminotransferase, aspartate aminotransferase, alkaline phosphatase, creatine kinase, gamma-glutamyl transferase, urea, glucose, cholesterol, triglycerides, total calcium, phosphorus, magnesium, chlorides, sodium, potassium, ionized calcium, creatinine, total protein, albumin, total, direct and indirect serum bilirubin. Serum protein fractionation was performed by sodium dodecyl sulphate-polyacrylamide gel electrophoresis (SDS-PAGE), which found 10 proteins: immunoglobulins A and G, ceruloplasmin, transferrin, albumin, haptoglobin, 1-acid glycoprotein, 138 kDa (MWP138), 33 kDa (MWP33) and 23 kDa (MWP23) molecular weight proteins. RBC and triglycerides were higher in pregnant females. Urea, Immunoglobulin A, MWP138 and MWP23 concentrations were higher in non-pregnant mares. This study presented differences from previous studies, and some differences in blood variables between pregnant and non-pregnant Pêga donkeys, confirming that pregnancy causes significant metabolic changes, which must be considered in the clinical evaluation of these animals.


Considerando a escassez de informações sobre as variáveis hematológicas dos jumentos Pêga e a influência de fatores como raça e estado fisiológico sobre estes parâmetros, este estudo teve como objetivo avaliar a influência da prenhez sobre os perfis hematológico, bioquímico sanguíneo e de proteínas séricas de jumentos Pêga, utilizando amostras de 59 jumentas adultas, 22 prenhes e 37 não prenhes, mantidas sob condições de campo. Foram mensuradas as contagens de hemácias, leucócitos, basófilos, eosinófilos, neutrófilos bastonetes, neutrófilos segmentados, linfócitos, monócitos e plaquetas; volume globular, concentração de hemoglobina e os níveis de alanina aminotransferase, aspartato aminotransferase, fosfatase alcalina, creatina quinase, gama glutamil transferase, ureia, glicose, colesterol, triglicérides, cálcio total, fósforo, magnésio, cloretos, sódio, potássio, cálcio ionizado, creatinina, proteína total, albumina, bilirrubina total, direta e indireta. O fracionamento de proteínas séricas foi realizado pela eletroforese em gel de acrilamida contendo dodecil sulfato de sódio (SDS-PAGE), o qual revelou 10 proteínas: imunoglobulinas A e G, ceruloplasmina, transferrina, albumina, haptoglobina, 1-glicoproteína ácida, proteína de peso molecular 138 kDa (PPM138), 33 kDa (PPM33) e 23 kDa (PPM23). A contagem de eritrócitos e os triglicérides séricos foram mais altos para as fêmeas prenhes. As concentrações de ureia, IgA, PPM138e PPM23 foram mais altas para jumentas não prenhes. Houve diferenças em relação a estudos anteriores, e diferenças entre as variáveis sanguíneas de jumentas Pêga prenhes e vazias confirmam que a prenhez causa mudanças metabólicas significantes, as quais devem ser consideradas na avaliação clínica destes animais.


Assuntos
Feminino , Animais , Gravidez , Equidae/sangue , Padrões de Referência , Proteínas Sanguíneas/análise , Contagem de Eritrócitos/veterinária , Eletroforese/veterinária , Testes Hematológicos/veterinária
14.
Ci. Rural ; 47(4): 01-07, Mar. 2017. graf, tab
Artigo em Inglês | VETINDEX | ID: vti-686868

RESUMO

Cyhalofop-butyl stands out among the herbicides in the control of midazolinone-resistant Echinochloa species; but, rice farmers are not always satisfied with the control achieved with this herbicide. The objectives were to evaluate in regional scale the susceptibility of Echinochloa populations to cyhalofop-butyl, and quantify the effect of the weed phenology on its efficacy of control. For this, three trials were carried out under greenhouse conditions with a fully random design, using Echinochloa populations collected in rice fields in the southern region of Brazil. In two trials, the susceptibility level of 156 (2012/13 growth season) and 103 (2013/14 growth season) populations were evaluated with the application of cyhalofop-butyl at 360g ha-1. In other trial, in which treatments were arranged in a bi-factorial design (A = 6 x B = 5), it was evaluated six cyhalofop-butyl rates and five phenological stages of E. crus-galli populations. Echinochloa populations had showed differential susceptibility to cyhalofop-butyl, especially in the 2013/14 growth season, where 20 out of the 103 populations had control lower than 90%. The efficacy of this herbicide was inversely proportional to the phenological stage, and the application timing delay contributed directly to the decrease of susceptibility to the herbicide. Cyhalofop-butyl is an effective alternative to control imidazolinone-resistant Echinochloa populations, as long as the application timing occurs in the early phenological stages (2 to 4 leaves).(AU)


Cyhalofop-butyl destaca-se dentre os herbicidas usados no manejo de populações de capim-arroz resistente às imidazolinonas, mas nem sempre o orizicultor fica satisfeito com o resultado obtido com este herbicida. Objetivou-se avaliar a suscetibilidade de populações de capim-arroz (Echinochloa spp.) ao cyhalofop-butyl e, quantificar o efeito da fenologia da infestante sobre a eficácia do seu controle. Para isto, três experimentos foram realizados em casa de vegetação com delineamento inteiramente casualizado, utilizando-se populações de capim-arroz coletadas na região Sul do Brasil. Em dois experimentos, a suscetibilidade de 156  (safra 2012/13) e 103 (safra 2013/14) populações foram avaliadas frente à aplicação do herbicida cyhalofop-butyl na dose de 360g ha-1. Em outro experimento, em que se arranjaram os tratamentos em esquema bi-fatorial, foram avaliados seis doses do herbicida e cinco estádios fenológicos de populações de E. crus-galli. Foi verificada variação na resposta das populações de capim-arroz ao cyhalofop-butyl, em especial na safra 2013/14, em que 20, das 103 populações testadas, tiveram controle menor que 90%. A eficácia do controle foi inversamente proporcional ao estádio fenológico e, o atraso no controle da infestante contribui diretamente para a diminuição da sua suscetibilidade ao herbicida. Cyhalofop-butyl é uma alternativa eficaz para controlar capim-arroz resistente às imidazolinonas, desde que a aplicação ocorra nos estádios iniciais de desenvolvimento (2 a 4 folhas).(AU)


Assuntos
Echinochloa , Resistência a Herbicidas/fisiologia , Herbicidas/análise , 24444
15.
Ciênc. rural (Online) ; 47(4): 01-07, Mar. 2017. graf, tab
Artigo em Inglês | VETINDEX | ID: biblio-1479914

RESUMO

Cyhalofop-butyl stands out among the herbicides in the control of midazolinone-resistant Echinochloa species; but, rice farmers are not always satisfied with the control achieved with this herbicide. The objectives were to evaluate in regional scale the susceptibility of Echinochloa populations to cyhalofop-butyl, and quantify the effect of the weed phenology on its efficacy of control. For this, three trials were carried out under greenhouse conditions with a fully random design, using Echinochloa populations collected in rice fields in the southern region of Brazil. In two trials, the susceptibility level of 156 (2012/13 growth season) and 103 (2013/14 growth season) populations were evaluated with the application of cyhalofop-butyl at 360g ha-1. In other trial, in which treatments were arranged in a bi-factorial design (A = 6 x B = 5), it was evaluated six cyhalofop-butyl rates and five phenological stages of E. crus-galli populations. Echinochloa populations had showed differential susceptibility to cyhalofop-butyl, especially in the 2013/14 growth season, where 20 out of the 103 populations had control lower than 90%. The efficacy of this herbicide was inversely proportional to the phenological stage, and the application timing delay contributed directly to the decrease of susceptibility to the herbicide. Cyhalofop-butyl is an effective alternative to control imidazolinone-resistant Echinochloa populations, as long as the application timing occurs in the early phenological stages (2 to 4 leaves).


Cyhalofop-butyl destaca-se dentre os herbicidas usados no manejo de populações de capim-arroz resistente às imidazolinonas, mas nem sempre o orizicultor fica satisfeito com o resultado obtido com este herbicida. Objetivou-se avaliar a suscetibilidade de populações de capim-arroz (Echinochloa spp.) ao cyhalofop-butyl e, quantificar o efeito da fenologia da infestante sobre a eficácia do seu controle. Para isto, três experimentos foram realizados em casa de vegetação com delineamento inteiramente casualizado, utilizando-se populações de capim-arroz coletadas na região Sul do Brasil. Em dois experimentos, a suscetibilidade de 156  (safra 2012/13) e 103 (safra 2013/14) populações foram avaliadas frente à aplicação do herbicida cyhalofop-butyl na dose de 360g ha-1. Em outro experimento, em que se arranjaram os tratamentos em esquema bi-fatorial, foram avaliados seis doses do herbicida e cinco estádios fenológicos de populações de E. crus-galli. Foi verificada variação na resposta das populações de capim-arroz ao cyhalofop-butyl, em especial na safra 2013/14, em que 20, das 103 populações testadas, tiveram controle menor que 90%. A eficácia do controle foi inversamente proporcional ao estádio fenológico e, o atraso no controle da infestante contribui diretamente para a diminuição da sua suscetibilidade ao herbicida. Cyhalofop-butyl é uma alternativa eficaz para controlar capim-arroz resistente às imidazolinonas, desde que a aplicação ocorra nos estádios iniciais de desenvolvimento (2 a 4 folhas).


Assuntos
Echinochloa , Herbicidas/análise , Resistência a Herbicidas/fisiologia , 24444
16.
Int J Vet Sci Med ; 5(1): 35-40, 2017 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-30255046

RESUMO

The electrophoretic fractionation represents one of the most reliable methods for the identification of blood proteins in ruminants. The aim of this study was to evaluate the serum proteinogram of sheep with acute ruminal lactic acidosis (ARA) using the SDS-PAGE electrophoresis technique. Ten Santa Inês ewes were used and blood was collected to establish the basal values for induction of ARA. Sucrose was administered orally in a single dose of 15 g/kg body mass. After the administration, blood samples were obtained at the following moments: 4, 8, 12, 16, 20, 24, 28, 32, 36, 48, 72, 96, 120 and 144 h. Subsequently, samples were obtained every seven days for three further weeks, until complete one month. The total of 13 proteins were identified: immunoglobulins A and G, ceruloplasmin, transferrin, albumin, α1-antitrypsin, haptoglobin, α1-acid glycoprotein, proteins of molecular weight 95, 46, 36 and 31 kDa. The increase of haptoglobin from 08 h coincides with the ruminal pH decrease, possibly due to the death of Gram negative bacteria and also the inflammatory process on the rumen. Fibrinogen was presented on highest mean at 48 h and returned to normal with 144 h. We can conclude that changes in serum levels of acute phase proteins can assist the clinical evaluation and diagnosis of ARA in sheep.

17.
Ci. Rural ; 47(4)2017.
Artigo em Inglês | VETINDEX | ID: vti-710044

RESUMO

ABSTRACT: Cyhalofop-butyl stands out among the herbicides in the control of imidazolinone-resistant Echinochloa species; but, rice farmers are not always satisfied with the control achieved with this herbicide. The objectives were to evaluate in regional scale the susceptibility of Echinochloa populations to cyhalofop-butyl, and quantify the effect of the weed phenology on its efficacy of control. For this, three trials were carried out under greenhouse conditions with a fully random design, using Echinochloa populations collected in rice fields in the southern region of Brazil. In two trials, the susceptibility level of 156 (2012/13 growth season) and 103 (2013/14 growth season) populations were evaluated with the application of cyhalofop-butyl at 360g ha-1. In other trial, in which treatments were arranged in a bi-factorial design (A = 6 x B = 5), it was evaluated six cyhalofop-butyl rates and five phenological stages of E. crus-galli populations. Echinochloa populations had showed differential susceptibility to cyhalofop-butyl, especially in the 2013/14 growth season, where 20 out of the 103 populations had control lower than 90%. The efficacy of this herbicide was inversely proportional to the phenological stage, and the application timing delay contributed directly to the decrease of susceptibility to the herbicide. Cyhalofop-butyl is an effective alternative to control imidazolinone-resistant Echinochloa populations, as long as the application timing occurs in the early phenological stages (2 to 4 leaves).


RESUMO: Cyhalofop-butyl destaca-se dentre os herbicidas usados no manejo de populações de capim-arroz resistente às imidazolinonas, mas nem sempre o orizicultor fica satisfeito com o resultado obtido com este herbicida. Objetivou-se avaliar a suscetibilidade de populações de capim-arroz (Echinochloa spp.) ao cyhalofop-butyl e, quantificar o efeito da fenologia da infestante sobre a eficácia do seu controle. Para isto, três experimentos foram realizados em casa de vegetação com delineamento inteiramente casualizado, utilizando-se populações de capim-arroz coletadas na região Sul do Brasil. Em dois experimentos, a suscetibilidade de 156 (safra 2012/13) e 103 (safra 2013/14) populações foram avaliadas frente à aplicação do herbicida cyhalofop-butyl na dose de 360g ha-1. Em outro experimento, em que se arranjaram os tratamentos em esquema bi-fatorial, foram avaliados seis doses do herbicida e cinco estádios fenológicos de populações de E. crus-galli. Foi verificada variação na resposta das populações de capim-arroz ao cyhalofop-butyl, em especial na safra 2013/14, em que 20, das 103 populações testadas, tiveram controle menor que 90%. A eficácia do controle foi inversamente proporcional ao estádio fenológico e, o atraso no controle da infestante contribui diretamente para a diminuição da sua suscetibilidade ao herbicida. Cyhalofop-butyl é uma alternativa eficaz para controlar capim-arroz resistente às imidazolinonas, desde que a aplicação ocorra nos estádios iniciais de desenvolvimento (2 a 4 folhas).

18.
Ciênc. rural ; Ciênc. rural (Online);47(4): e20160839, 2017. tab, graf
Artigo em Inglês | LILACS | ID: biblio-839776

RESUMO

ABSTRACT: Cyhalofop-butyl stands out among the herbicides in the control of imidazolinone-resistant Echinochloa species; but, rice farmers are not always satisfied with the control achieved with this herbicide. The objectives were to evaluate in regional scale the susceptibility of Echinochloa populations to cyhalofop-butyl, and quantify the effect of the weed phenology on its efficacy of control. For this, three trials were carried out under greenhouse conditions with a fully random design, using Echinochloa populations collected in rice fields in the southern region of Brazil. In two trials, the susceptibility level of 156 (2012/13 growth season) and 103 (2013/14 growth season) populations were evaluated with the application of cyhalofop-butyl at 360g ha-1. In other trial, in which treatments were arranged in a bi-factorial design (A = 6 x B = 5), it was evaluated six cyhalofop-butyl rates and five phenological stages of E. crus-galli populations. Echinochloa populations had showed differential susceptibility to cyhalofop-butyl, especially in the 2013/14 growth season, where 20 out of the 103 populations had control lower than 90%. The efficacy of this herbicide was inversely proportional to the phenological stage, and the application timing delay contributed directly to the decrease of susceptibility to the herbicide. Cyhalofop-butyl is an effective alternative to control imidazolinone-resistant Echinochloa populations, as long as the application timing occurs in the early phenological stages (2 to 4 leaves).


RESUMO: Cyhalofop-butyl destaca-se dentre os herbicidas usados no manejo de populações de capim-arroz resistente às imidazolinonas, mas nem sempre o orizicultor fica satisfeito com o resultado obtido com este herbicida. Objetivou-se avaliar a suscetibilidade de populações de capim-arroz (Echinochloa spp.) ao cyhalofop-butyl e, quantificar o efeito da fenologia da infestante sobre a eficácia do seu controle. Para isto, três experimentos foram realizados em casa de vegetação com delineamento inteiramente casualizado, utilizando-se populações de capim-arroz coletadas na região Sul do Brasil. Em dois experimentos, a suscetibilidade de 156 (safra 2012/13) e 103 (safra 2013/14) populações foram avaliadas frente à aplicação do herbicida cyhalofop-butyl na dose de 360g ha-1. Em outro experimento, em que se arranjaram os tratamentos em esquema bi-fatorial, foram avaliados seis doses do herbicida e cinco estádios fenológicos de populações de E. crus-galli. Foi verificada variação na resposta das populações de capim-arroz ao cyhalofop-butyl, em especial na safra 2013/14, em que 20, das 103 populações testadas, tiveram controle menor que 90%. A eficácia do controle foi inversamente proporcional ao estádio fenológico e, o atraso no controle da infestante contribui diretamente para a diminuição da sua suscetibilidade ao herbicida. Cyhalofop-butyl é uma alternativa eficaz para controlar capim-arroz resistente às imidazolinonas, desde que a aplicação ocorra nos estádios iniciais de desenvolvimento (2 a 4 folhas).

19.
Ci. Rural ; 46(9): 1656-1661, Sept. 2016. tab, graf
Artigo em Inglês | VETINDEX | ID: vti-29709

RESUMO

The aim of this research was to evaluate the dimensional reduction of additive direct genetic covariance matrices in genetic evaluations of growth traits (range 100-730 days) in Simmental cattle using principal components, as well as to estimate (co)variance components and genetic parameters. Principal component analyses were conducted for five different models-one full and four reduced-rank models. Models were compared using Akaike information (AIC) and Bayesian information (BIC) criteria. Variance components and genetic parameters were estimated by restricted maximum likelihood (REML). The AIC and BIC values were similar among models. This indicated that parsimonious models could be used in genetic evaluations in Simmental cattle. The first principal component explained more than 96% of total variance in both models. Heritability estimates were higher for advanced ages and varied from 0.05 (100 days) to 0.30 (730 days). Genetic correlation estimates were similar in both models regardless of magnitude and number of principal components. The first principal component was sufficient to explain almost all genetic variance. Furthermore, genetic parameter similarities and lower computational requirements allowed for parsimonious models in genetic evaluations of growth traits in Simmental cattle.(AU)


Objetivou-se estudar a efetividade da redução da dimensão da matriz de covariância do efeito genético direto na avaliação genética do crescimento (pesos dos 100 aos 730 dias de idade) de bovinos Simental, por meio da análise de componentes principais, e estimar componentes de (co)variância e parâmetros genéticos. A análise de componentes principais foi realizada ajsutando-se cinco diferentes modelos: um modelo multicaracterístico padrão, de posto completo, e quatro modelos de posto reduzido. Os modelos foram comparados via informação de Akaike (AIC) e informação Bayesiana de Schwarz (BIC). Os componentes de variância e parâmetros genéticos foram obtidos via REML. Os valores de AIC e BIC para os modelos testados foram similares, indicando a possibilidade da escolha de um modelo mais parcimonioso na avaliação genética da raça Simental. O primeiro componente principal explicou mais de 96% de toda variação genética aditiva direta em ambos os modelos. Os valores de herdabilidades foram maiores em idades mais avançadas e variaram de 0,05 (peso aos 100 dias) a 0,30 (peso aos 730 dias). As estimativas de correlações genéticas foram similares em todos os modelos e apresentaram mesma magnitude e comportamento independentemente do número de componentes principais adotado. Diante dos resultados, pode-se afirmar que apenas o primeiro componente principal foi suficiente para explicar quase que na totalidade a variação genética aditiva direta existente. Além disso, a similaridade dos parâmetros genéticos estimados e a menor demanda computacional são indicativos da possibilidade da utilização de modelos mais parcimoniosos na avaliação genética de bovinos Simental.(AU)


Assuntos
Animais , Bovinos , Bovinos/crescimento & desenvolvimento , Bovinos/genética , Aumento de Peso/genética
20.
Ciênc. rural ; Ciênc. rural (Online);46(9): 1656-1661, tab, graf
Artigo em Inglês | LILACS | ID: lil-787398

RESUMO

ABSTRACT: The aim of this research was to evaluate the dimensional reduction of additive direct genetic covariance matrices in genetic evaluations of growth traits (range 100-730 days) in Simmental cattle using principal components, as well as to estimate (co)variance components and genetic parameters. Principal component analyses were conducted for five different models-one full and four reduced-rank models. Models were compared using Akaike information (AIC) and Bayesian information (BIC) criteria. Variance components and genetic parameters were estimated by restricted maximum likelihood (REML). The AIC and BIC values were similar among models. This indicated that parsimonious models could be used in genetic evaluations in Simmental cattle. The first principal component explained more than 96% of total variance in both models. Heritability estimates were higher for advanced ages and varied from 0.05 (100 days) to 0.30 (730 days). Genetic correlation estimates were similar in both models regardless of magnitude and number of principal components. The first principal component was sufficient to explain almost all genetic variance. Furthermore, genetic parameter similarities and lower computational requirements allowed for parsimonious models in genetic evaluations of growth traits in Simmental cattle.


RESUMO: Objetivou-se estudar a efetividade da redução da dimensão da matriz de covariância do efeito genético direto na avaliação genética do crescimento (pesos dos 100 aos 730 dias de idade) de bovinos Simental, por meio da análise de componentes principais, e estimar componentes de (co)variância e parâmetros genéticos. A análise de componentes principais foi realizada ajsutando-se cinco diferentes modelos: um modelo multicaracterístico padrão, de posto completo, e quatro modelos de posto reduzido. Os modelos foram comparados via informação de Akaike (AIC) e informação Bayesiana de Schwarz (BIC). Os componentes de variância e parâmetros genéticos foram obtidos via REML. Os valores de AIC e BIC para os modelos testados foram similares, indicando a possibilidade da escolha de um modelo mais parcimonioso na avaliação genética da raça Simental. O primeiro componente principal explicou mais de 96% de toda variação genética aditiva direta em ambos os modelos. Os valores de herdabilidades foram maiores em idades mais avançadas e variaram de 0,05 (peso aos 100 dias) a 0,30 (peso aos 730 dias). As estimativas de correlações genéticas foram similares em todos os modelos e apresentaram mesma magnitude e comportamento independentemente do número de componentes principais adotado. Diante dos resultados, pode-se afirmar que apenas o primeiro componente principal foi suficiente para explicar quase que na totalidade a variação genética aditiva direta existente. Além disso, a similaridade dos parâmetros genéticos estimados e a menor demanda computacional são indicativos da possibilidade da utilização de modelos mais parcimoniosos na avaliação genética de bovinos Simental.

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