Contributions of seminal plasma proteins to fertilizing ability of bull sperm: A meta-analytical review.

Seminal plasma is a dynamic, intricate combination of fluids from the testicles, epididymides, seminal vesicles, bulbourethral glands, and prostate, containing molecules that modulate sperm functions, post-fertilization events, and the female reproductive tract physiology. Significant variations in sperm parameters and fertility status of bulls relate to differences in the seminal plasma proteome. In this framework, a meta-analytical study was conducted examining 29 studies (published between 1990 and 2021) to ascertain the effects of seminal fluid proteins on parameters associated with bull fertility and the influence of distinct methodologies on such effects. Our results revealed that seminal proteins ameliorate sperm parameters, such as motility, integrity, capacitation, and fertilizing ability, and favours sperm protection. Seminal binder of sperm proteins and beta-defensin 126 highly favoured sperm protection when cells were collected from the epididymis by retrograde flux and analysed under room temperature conditions. Furthermore, seminal proteins improved the motility and quality of Bos taurus sperm collected by artificial vagina, mainly in the presence of heparin-binding proteins. The key limitations faced by this meta-analysis were the paucity of studies evaluating the effects of whole seminal fluid proteins and the limited number of studies conducted in vivo. In conclusion, the present meta-analytical study confirms that seminal proteins improve fertility-related parameters in the bovine species. However, methodological strategies used by authors are diverse, with distinct endpoints and methods. Thus, the translational aspects of seminal plasma research should be taken into consideration to precisely define how seminal proteins can be harnessed to advance reproductive biotechnology.

H2O2 priming induces proteomic responses to defense against salt stress in maize.

KEY MESSAGE: H2O2 priming reprograms essential proteins' expression to help plants survive, promoting responsive and unresponsive proteins adjustment to salt stress. ABSTACRT: Priming is a powerful strategy to enhance abiotic stress tolerance in plants. Despite this, there is scarce information about the mechanisms induced by H2O2 priming for salt stress tolerance, particularly on proteome modulation. Improving maize cultivation in areas subjected to salinity is imperative for the local economy and food security. Thereby, this study aimed to investigate physiological changes linked with post-translational protein events induced by foliar H2O2 priming of Zea mays plants under salt stress. As expected, salt treatment promoted a considerable accumulation of Na+ ions, a 12-fold increase. It drastically affected growth parameters and relative water content, as well as promoted adverse alteration in the proteome profile, when compared to the absence of salt conditions. Conversely, H2O2 priming was beneficial via specific proteome reprogramming, which promoted better response to salinity by 16% reduction in Na+ content and shoots growth improvement, increasing 61% in dry mass. The identified proteins were associated with photosynthesis and redox homeostasis, critical metabolic pathways for helping plants survive in saline stress by the protection of chloroplasts organization and carbon fixation, as well as state redox. This research provides new proteomic data to improve understanding and forward identifying biotechnological strategies to promote salt stress tolerance.

First proteomic analysis of diestrus and anestrus canine oocytes at the germinal vesicle reveals candidate proteins involved in oocyte meiotic competence.

In domestic dogs, oocyte maturation rates are low and the percentage of oocytes that remain in the stage of germinal vesicle (GV) regardless of culture conditions is high. The present study was conducted to characterize the proteome of canine oocyte at the germinal vesicle stage using label-free mass spectrometry. Ovaries were collected from 415 adult domestic dogs and oocytes were divided anestrus and diestrus group. Protein lysates were subjected to quantitative proteomic analysis to identify differentially expressed proteins in different status reproductive. All runs for each sample were performed on an Easy nLC1000 nano-LC chromatograph system directly connected to a quadrupole-type Orbitrap mass spectrometer. For identification of peptides and proteins, raw data of the spectra were loaded into MaxQuant software version 1.5.2.8. Proteomic data were analysed according to gene ontology and a protein-protein interaction network. 312 proteins were identified and grouped according to their biological processes, molecular functions and cellular component. Forty-six differentially expressed proteins among diestrus and control group were associated with at least one GO term in the biological process database. Several proteins involved in the cell cycle, fertilization, regulation of transcription and signalling pathways that are essential for the full development of oocytes and fertilization were expressed. This study identified proteins that were absent, and more or less expressed in different status reproductive. These differentially expressed proteins revealed a framework of molecular reorganization within a GV that renders its competency. This knowledge will enable the identification of target competence biomarkers and thus the establishment of more adequate means of cultivation to improve the M-I and II indexes in this species and also to better understand the physiology of the domestic dog, promoting the development of new reproduction biotechniques.

Proteome of the periovulatory oviduct and uterus of goats as related to nutritional balance.

This study was conducted to evaluate the effects of different feeding levels on the proteome of oviduct and uterus tissues of hormonally stimulated goats during the periovulatory period. Forty goats were separated into four different diet groups: Diet 1.0 M (n = 11), Diet 1.3 M (n = 10), Diet 1.6 M (n = 9), Diet 1.9 M (n = 10), fed with 1.0, 1.3, 1.6 and 1.9 times live weight maintenance, respectively. After four weeks of treatment, six hormonally stimulated females per treatment group were randomly selected for collection of uterine and the oviduct tissue samples. Samples were collected after animals were slaughtered in a commercial unit. Feeding goats with 1.3 to 1.9 times more nutrients than a control group directly influenced the proteome of the oviduct and uterus, altering the expression of proteins that participate in biological processes such as apoptosis, antioxidant, and immunological activities. These events are crucial for fertilization and early embryonic survival. Expression of oviduct proteins such as Tubulin Beta 2B, Transferrin and Disulphide-isomerase A3 increased in the 1.9 M group in relation to the other feeding levels. Disulphide-isomerase A4 showed higher expression in the 1.0 M group compared to diets with higher energetic levels. As energy intake increased in the diets, there was higher expression of Alpha-1-antitrypsin and downregulation of Profilin-1 in the uterus of the goats. In conclusion, this study showed that specific proteins of the goat oviduct and uterus expressed during the periovulatory period are modified as the result of nutritional balance.

Label-free proteome of water buffalo (Bubalus bubalis) seminal plasma.

The study aimed to describe the Bubalus bubalis seminal plasma proteome using a label-free shotgun UDMSE approach. A total of 859 nonredundant proteins were identified across five biological replicates with stringent identification. Proteins specifically related to sperm maturation and protection, capacitation, fertilization and metabolic activity were detected in the buffalo seminal fluid. In conclusion, we provide a comprehensive proteomic profile of buffalo seminal plasma, which establishes a foundation for further studies designed to understand regulation of sperm function and discovery of novel biomarkers for fertility. MS data are available in the ProteomeXchange with identifier PXD003728.

Activin-A promotes the development of goat isolated secondary follicles in vitro.

The role of activin-A in follicular development and on the mRNA expression levels of different genes in goat secondary follicles was evaluated. Goat secondary follicles (≥ 150 µm) were cultured for 18 days under control conditions or with the addition of either 50 or 100 ng/ml activin-A (Experiment 1). The mRNA levels for the genes that code for activin-A, ActR-IA, ActR-IB, ActR-IIA, ActR-IIB, follicle stimulating hormone receptor (FSH-R) and P450 aromatase were measured in each condition (Experiment 2). We observed that after 6 days of culture, the antrum formation rate was higher in cultures with added activin-A than in the cultured control (P < 0.05). The addition of 50 ng/ml activin-A increased the follicular growth rate in the final third of the culture (days 12-18), resulting in a higher percentage of meiosis resumption (P < 0.05). On day 6, the addition of activin-A (50 ng/ml) increased the levels of ActR-IA mRNA compared with the cultured control (P < 0.05). After 18 days, the addition of 50 ng/ml activin-A significantly increased the levels of its own mRNA compared with the non-cultured control. Moreover, this treatment reduced the mRNA levels of P450 aromatase in comparison with the cultured control (P < 0.05). Higher levels of P450 aromatase mRNA were found for both activin-A treatments compared with the non-cultured control (P < 0.05). No difference in estradiol levels was detected among any of the tested treatments. In conclusion, the addition of activin-A to culture medium stimulated early antrum formation as well as an increase in the daily follicular growth rate and the percentage of meiosis resumption.

HPV infection and 5mC/5hmC epigenetic markers in penile squamous cell carcinoma: new insights into prognostics.

BACKGROUND: Penile cancer is one of the most aggressive male tumors. Although it is preventable, the main etiologic causes are lifestyle behaviors and viral infection, such as human papillomavirus (HPV). Long-term epigenetic changes due to environmental factors change cell fate and promote carcinogenesis, being an important marker of prognosis. We evaluated epidemiological aspects of penile squamous cell carcinoma (SCC) and the prevalence of HPV infection using high-risk HPV (hrHPV) and p16INK4A expression of 224 participants. Global DNA methylation was evaluated through 5-methylcytosine (5mC) and 5-hydroxymethylcytosine (5hmC). RESULTS: The incidence of HPV was 53.2% for hrHPV and 22.32% for p16INK4a. hrHPV was not related to systemic or lymph node metastasis and locoregional recurrence, nor influenced the survival rate. P16INK4a seems to be a protective factor for death, which does not affect metastasis or tumor recurrence. Lymph node and systemic metastases and locoregional recurrence increase the risk of death. An increased 5mC mark was observed in penile SCC regardless of HPV infection. However, there is a reduction of the 5hmC mark for p16INK4a + (P = 0.024). Increased 5mC/5hmC ratio (> 1) was observed in 94.2% of penile SCC, irrespective of HPV infection. Despite the increase in 5mC, it seems not to affect the survival rate (HR = 1.06; 95% CI 0.33-3.38). CONCLUSIONS: P16INK4a seems to be a good prognosis marker for penile SCC and the increase in 5mC, an epigenetic mark of genomic stability, may support tumor progression leading to poor prognosis.

Ultrastructural description of fresh and frozen/thawed sperm derived from collared peccaries (Pecari tajacu Linnaeus, 1,758).

The aim was to describe, through scanning electron microscopy (SEM) and transmission electron microscopy (TEM), the ultrastructure of peccaries' fresh and frozen-thawed sperm. For that, semen derived from three mature males was obtained by electroejaculation and evaluated for motility, membrane integrity, membrane functionality, chromatin integrity, and morphology through light microscopy. Samples were frozen using a Tris extender plus egg yolk (20%) and glycerol (6%). Then, fresh and frozen-thawed semen samples were mixed in different sperm pools that were processed for SEM and TEM. Sperm motility, membrane integrity, and functionality were impaired (p < .05) by freezing-thawing procedures, but sperm morphology, and chromatin integrity evaluated by light microscopy were not significantly affected. The SEM revealed that peccaries' sperm presents a flattened head in a paddle format, measuring 6.07 µm in length and 3.84 µm in width, with a vastus acrosome (4.46 µm). Normal tails measure 38.11 µm, being formed by an extensive midpiece with 15.52 µm in length. In frozen-thawed samples, both SEM and TEM provide us information about damage undetected through light microscopy as the presence of vesicles in the acrosome, loose plasma membrane, vacuolized mitochondria, dense fibers disorganized, and decondensed chromatin. In conclusion, we provide the first description of the sperm ultrasctruture in collared peccaries. Moreover, SEM and TEM help us to identify some nanometric damage provoked by freezing-thawing procedures, thus providing valuable information for the improvement of such important protocols used for biobanking formation.

Feeding effects of cottonseed and its co-products on the meat proteome from ram lambs

Gossypol easily pairs with lysine side chains and enzymes involved in the cellular growth process. The effect of gossypol (a compound present in cotton co-products) in ruminant metabolism and meat quality is not yet clear. This study was undertaken in order to evaluate the effects of cotton co-products in lamb muscle proteome. Twenty-four Santa Inês ram lambs, 5-months old (20.6 ± 1.9 kg), were randomly assigned to four treatments: control (without cottonseed), whole cottonseed, cottonseed meal and high oil cottonseed meal. At 95 days into the experiment, lambs were slaughtered and samples from Longissimus dorsi were collected. Proteins were extracted and analyzed by 2-D electrophoresis. Spots showing a significant effect from the treatment (the “treatment effect”) and present in more than 90 % of the samples were identified using mass spectrometry. Cotton co-products decreased the abundance of aldehyde and malate dehydrogenases, creatine kinase M-type and Adenosine triphosphate (ATP) synthase. They also increased four proteins related to muscle contraction. Thus, feeding cotton co-products to lambs changed the abundance of important muscle proteins. A cotton co-product diet induced a negative impact on the energy supply of muscle cells and, consequently, the abundance of ATP dependent proteins (contractile apparatus) increased, probably in order to offset and maintain muscle function. These proteomic changes can promote our understanding of alterations in the sensorial properties of meat due to cotton co-product diets in further investigations.

Feeding effects of cottonseed and its co-products on the meat proteome from ram lambs

Gossypol easily pairs with lysine side chains and enzymes involved in the cellular growth process. The effect of gossypol (a compound present in cotton co-products) in ruminant metabolism and meat quality is not yet clear. This study was undertaken in order to evaluate the effects of cotton co-products in lamb muscle proteome. Twenty-four Santa Inês ram lambs, 5-months old (20.6 ± 1.9 kg), were randomly assigned to four treatments: control (without cottonseed), whole cottonseed, cottonseed meal and high oil cottonseed meal. At 95 days into the experiment, lambs were slaughtered and samples from Longissimus dorsi were collected. Proteins were extracted and analyzed by 2-D electrophoresis. Spots showing a significant effect from the treatment (the “treatment effect”) and present in more than 90 % of the samples were identified using mass spectrometry. Cotton co-products decreased the abundance of aldehyde and malate dehydrogenases, creatine kinase M-type and Adenosine triphosphate (ATP) synthase. They also increased four proteins related to muscle contraction. Thus, feeding cotton co-products to lambs changed the abundance of important muscle proteins. A cotton co-product diet induced a negative impact on the energy supply of muscle cells and, consequently, the abundance of ATP dependent proteins (contractile apparatus) increased, probably in order to offset and maintain muscle function. These proteomic changes can promote our understanding of alterations in the sensorial properties of meat due to cotton co-product diets in further investigations.(AU)

Proteins of the canine seminal plasma / Proteínas do plasma seminal canino

ABSTRACT: Studies have been performed to identify the proteins present in canine seminal plasma (SP) and relate them to sperm quality as well as to discover molecular markers of reproductive tract diseases. There is evidence that heparin-binding proteins, zinc-binding proteins, and lactoferrin as well as the matrix metalloproteinase, superoxide dismutase, catalase, and glutathione peroxidase enzymes are associated with canine sperm quality. Other studies indicate that prolactin and enzymes like arginine esterase, acid phosphatase, and alkaline phosphatase could be successfully used as biomarkers of reproductive disorders. Thus, the present literature review aims to address aspects related to proteins of the canine SP, their influence on fertility, and their importance as biomarkers of reproductive disorders.

RESUMO: Pesquisas têm sido realizadas para identificar as proteínas presentes no plasma seminal canino, com o intuito de relacioná-las com a qualidade espermática, bem como buscar por marcadores moleculares de patologias do trato reprodutivo. Há evidências de que as proteínas ligadoras de heparina, ligadoras de zinco, a lactoferrina, bem como as enzimas matrix metalloproteinase, superoxide dismutase, catalase e a glutationa peroxidase estão relacionadas com a qualidade seminal canina. Outras pesquisas indicam que a prolactina, e as enzimas arginina esterase, fosfatase ácida e fosfatase alcalina poderiam ser utilizadas com sucesso como biomarcadores de doenças reprodutivas. Assim, esta revisão de literatura objetiva abordar aspectos relacionados às proteínas do plasma seminal canino, suas influências sobre a fertilidade, e sua importância como biomarcadores de doenças reprodutivas.

Proteins of the canine seminal plasma / Proteínas do plasma seminal canino

Studies have been performed to identify the proteins present in canine seminal plasma (SP) and relate them to sperm quality as well as to discover molecular markers of reproductive tract diseases. There is evidence that heparin-binding proteins, zinc-binding proteins, and lactoferrin as well as the matrix metalloproteinase, superoxide dismutase, catalase, and glutathione peroxidase enzymes are associated with canine sperm quality. Other studies indicate that prolactin and enzymes like arginine esterase, acid phosphatase, and alkaline phosphatase could be successfully used as biomarkers of reproductive disorders. Thus, the present literature review aims to address aspects related to proteins of the canine SP, their influence on fertility, and their importance as biomarkers of reproductive disorders.(AU)

Pesquisas têm sido realizadas para identificar as proteínas presentes no plasma seminal canino, com o intuito de relacioná-las com a qualidade espermática, bem como buscar por marcadores moleculares de patologias do trato reprodutivo. Há evidências de que as proteínas ligadoras de heparina, ligadoras de zinco, a lactoferrina, bem como as enzimas matrix metalloproteinase, superoxide dismutase, catalase e a glutationa peroxidase estão relacionadas com a qualidade seminal canina. Outras pesquisas indicam que a prolactina, e as enzimas arginina esterase, fosfatase ácida e fosfatase alcalina poderiam ser utilizadas com sucesso como biomarcadores de doenças reprodutivas. Assim, esta revisão de literatura objetiva abordar aspectos relacionados às proteínas do plasma seminal canino, suas influências sobre a fertilidade, e sua importância como biomarcadores de doenças reprodutivas.(AU)

Avaliação da maturação nuclear de oócitos bovinos submetidos a três diferentes sistemas de incubação / Evaluation of nuclear maturation of bovine oocytes submitted to three different incubation systems

This study aimed to evaluate three different incubation systems in nuclear maturation of bovine oocytes.Follicles of 2 to 8 mm in diameter were aspirated for obtaining cumulus-oocyte complexes (COCs). Thereafter,COCs were subjected to in vitro maturation (IVM) in TCM-199 medium supplemented at 38.5 °C for 23 h indifferent incubation systems: bench incubator with high oxygen (20% O2 in air), bench incubator with lowoxygen (5% O2) and portable incubator with low oxygen. After IVM, cumulus cells were removed and oocyteswere stained with Hoechst 33342. The slides were analyzed by a fluorescence microscope and the oocytes wereclassified into: degenerated (DG), metaphase I (MI) and metaphase II (MII). No difference (P > 0.05) wasobserved among the rates of DG, MI and MII for the different incubation systems. Therefore, the use of portableincubation system is a viable alternative for in vitro maturation of bovine oocytes.(AU)

Avaliação da maturação nuclear de oócitos bovinos submetidos a três diferentes sistemas de incubação / Evaluation of nuclear maturation of bovine oocytes submitted to three different incubation systems

This study aimed to evaluate three different incubation systems in nuclear maturation of bovine oocytes.Follicles of 2 to 8 mm in diameter were aspirated for obtaining cumulus-oocyte complexes (COCs). Thereafter,COCs were subjected to in vitro maturation (IVM) in TCM-199 medium supplemented at 38.5 °C for 23 h indifferent incubation systems: bench incubator with high oxygen (20% O2 in air), bench incubator with lowoxygen (5% O2) and portable incubator with low oxygen. After IVM, cumulus cells were removed and oocyteswere stained with Hoechst 33342. The slides were analyzed by a fluorescence microscope and the oocytes wereclassified into: degenerated (DG), metaphase I (MI) and metaphase II (MII). No difference (P > 0.05) wasobserved among the rates of DG, MI and MII for the different incubation systems. Therefore, the use of portableincubation system is a viable alternative for in vitro maturation of bovine oocytes.

Biometria testicular, concentrações periféricas de testosterona, parâmetros seminais e número de células de Sertoli e germinativas em touros Nelore / Testis size, peripheral concentrations of testosterone, semen criteria and Sertoli and germ cell numbers in Nelore bulls

A study was conducted to evaluate the associations among testis size, testosterone concentrations,semen parameters and aspects of spermatogenesis in Nelore bulls (n = 28). Testis size was measuredfrom 10 to 29 months of age. Bulls were treated with GnRH (12 to 21 months) and semen samples alsocollected from 25 to 29 months. At 30 months, animals were slaughtered. Correlations were significantwhen p < 0.05. Basal testosterone was highest at 18 months, suggesting that bulls reached puberty at thisage. At 30 months, seminiferous tubules represented 77.9 ± 3.8 % of the testicular parenchyma and therewere 33.6 ± 8.4 round spermatids/A1 spermatogonium/tubule section, indicating a 47.5% degeneration rate during spermatogenesis. At 30 months, heavier testis correlated with Sertoli cell numbers/testis (r= 0.77), and round spermatids/tubule section, Sertoli cell and A1 spermatogonium (r = 0.50 0.60).Scrotal circumference (SC) taken between 10 and 29 months correlated with the percentage of tubuleswith spermatids (r = 0.42 0.59) and number of A1 spermatogonium and round spermatids/Sertoli cell(r = 0.49 0.68). Epididymal weight was related to Sertoli cell numbers/testis, and round spermatids/Sertoli cell and A1 spermatogonium (r = 0.51 0.61). GnRH-stimulated testosterone from 17 to 21months correlated with SC between 14 and 29 months (r = 0.48 0.60), testis and epididymal weights(r = 0.41 0.64) and with parameters of spermatogenesis (r = 0.44 0.58). Additionally, sperm motilityand vigor from 25 to 29 months correlated with the number of tubules with spermatids (r = 0.42 0.59)and GnRH-stimulated testosterone at 12, 13 and 18 months (r = 0.46 0.57). In conclusion, testissize during and after the period of pronounced increases in testosterone is an indicator of quantitativeparameters of spermatogenesis of post-pubertal bulls.(AU)

Conduziu-se o presente estudo com o objetivo de avaliar as associações entre biometria testicular, testosterona, parâmetros seminais e aspectos da espermatogênese em touros Nelore (n = 28). Avaliou-se os testículos dos 10 aos 29 meses de idade. Os touros foram tratados com GnRH (12 a 21 meses) e amostras de sêmen coletadas (25 a 29 meses). Aos 30 meses, os animais foram abatidos. Correlações foram consideradas significativas quando p < 0.05. Concentrações elevadas de testosterona basal ocorreram aos 18 meses, indicativo da puberdade dos touros. Aos 30 meses, os túbulos seminíferosrepresentaram 77,9 ± 3,8% do parênquima testicular e quantificou-se 33,6 ± 8,4 espermátides arredondadas/espermatogônia A1/secção tubular, referente a 47,5% de degeneração celular durante a espermatogênese. Aos 30 meses, peso testicular correlacionou-se com o número de células de Sertoli/ testículo (r = 0,77) e espermátides arredondadas/seção tubular, célula de Sertoli e espermatogônia A1 (r = 0,50 0,60). A circunferência escrotal (CE) entre 10 e 29 meses correlacionou-se com a percentagem de túbulos com espermátides (r = 0,42 0,59) e número de espermatogônias e espermátides arredondadas/ célula de Sertoli (r = 0,49 0,68). Detectou-se correlações entre peso epididimário e número de células de Sertoli/testículo e espermátides arredondadas/célula de Sertoli e espermatogônia A1 (r = 0,51 0,61). Testosterona pós-GnRH (17 aos 21 meses) apresentou relação com a CE entre 14 e 29 meses (r = 0,48 0,60), peso testicular e epididimário (r = 0,41 0,64) e parâmetros da espermatogênese (r = 0,44 0,58). Motilidade e vigor espermático (25 aos 29 meses) correlacionaram-se com o número de túbulos com espermátides (r = 0,42 0,59) e testosterona pós-GnRH aos 12, 13 e 18 meses (r = 0,46 0,57). Portanto, a biometria testicular durante e após a ocorrência dos níveis concentrações elevadas de testosterona é um indicador dos parâmetros quantitativos da espermatogênese em touros pós púberes.(AU)

Concentrações séricas de glicose e ureia em bezerras mestiças alimentadas com sucedâneo lácteo e probiótico / Serum concentrations of glucose and urea in crossbred heifers fed a milk replacer and probiotic

Objetivou-se através deste estudo avaliar a influência de dieta líquida a base de sucedâneo lácteo com ou sem adição de probiótico sobre o desempenho de bezerras através das concentrações de glicose e ureia na corrente sanguínea. Foram utilizadas 24 bezerras em delineamento inteiramente casualizado com quatro tratamentos e seis repetições: abrigos locados ao sol e aleitamento com sucedâneo; abrigos locados ao sol e aleitamento com sucedâneo adicionado de probiótico; abrigos com sombra suplementar e aleitamento com sucedâneo; e abrigos com sombra suplementar e aleitamento com sucedâneo adicionado de probiótico. Os efeitos dos diferentes tratamentos sobre cada variável foram comparados por meio do teste de Tukey, ao nível de 5% de probabilidade. As concentrações de glicose e ureia plasmáticas não diferiram entre os tratamentos, nem entre os períodos pré e pós-desmame. A semelhança provavelmente está associada ao fato de que o consumo de matéria seca total apresentou reduzida variação entre os mesmos. O fornecimento do probiótico a dieta líquida de bezerras mestiças e sombra suplementar não afetaram os metabólicos sanguíneos, logo sendo dispensável sua utilização para as condições em que o experimento foi realizado.

This study aimed to evaluate the influence of the liquid diet with milk replacer, with or without the addition of probiotics, on the performance of calves by measurement of concentrations of glucose and urea in the bloodstream. Twenty-four calves, distributed in a completely randomized design with four treatments and six replications were used: Shelters allocated to the sun and fed with milk replacer; Shelters allocated to the sun and fed with milk replacer plus probiotics; Shelters with additional shade and fed with milk replacer; and Shelters with additional shade and fed with milk replacer plus probiotics. The variables were tested by Tukey test, at 5% probability. The concentrations of plasma glucose and urea did not significantly differ between treatments, nor between the period pre and post-weaning. The similarity is probably associated with the fact that consumption of total dry matter showed little variation between them. The probiotic supply at liquid diet for crossbred heifers and additional shade did not affect the metabolic blood evaluated, then this use is not necessary for the conditions under which the experiment was conducted.

Biometria testicular, concentrações periféricas de testosterona, parâmetros seminais e número de células de Sertoli e germinativas em touros Nelore / Testis size, peripheral concentrations of testosterone, semen criteria and Sertoli and germ cell numbers in Nelore bulls

A study was conducted to evaluate the associations among testis size, testosterone concentrations,semen parameters and aspects of spermatogenesis in Nelore bulls (n = 28). Testis size was measuredfrom 10 to 29 months of age. Bulls were treated with GnRH (12 to 21 months) and semen samples alsocollected from 25 to 29 months. At 30 months, animals were slaughtered. Correlations were significantwhen p < 0.05. Basal testosterone was highest at 18 months, suggesting that bulls reached puberty at thisage. At 30 months, seminiferous tubules represented 77.9 ± 3.8 % of the testicular parenchyma and therewere 33.6 ± 8.4 round spermatids/A1 spermatogonium/tubule section, indicating a 47.5% degeneration rate during spermatogenesis. At 30 months, heavier testis correlated with Sertoli cell numbers/testis (r= 0.77), and round spermatids/tubule section, Sertoli cell and A1 spermatogonium (r = 0.50 – 0.60).Scrotal circumference (SC) taken between 10 and 29 months correlated with the percentage of tubuleswith spermatids (r = 0.42 – 0.59) and number of A1 spermatogonium and round spermatids/Sertoli cell(r = 0.49 – 0.68). Epididymal weight was related to Sertoli cell numbers/testis, and round spermatids/Sertoli cell and A1 spermatogonium (r = 0.51 – 0.61). GnRH-stimulated testosterone from 17 to 21months correlated with SC between 14 and 29 months (r = 0.48 – 0.60), testis and epididymal weights(r = 0.41 – 0.64) and with parameters of spermatogenesis (r = 0.44 – 0.58). Additionally, sperm motilityand vigor from 25 to 29 months correlated with the number of tubules with spermatids (r = 0.42 – 0.59)and GnRH-stimulated testosterone at 12, 13 and 18 months (r = 0.46 – 0.57). In conclusion, testissize during and after the period of pronounced increases in testosterone is an indicator of quantitativeparameters of spermatogenesis of post-pubertal bulls.

Conduziu-se o presente estudo com o objetivo de avaliar as associações entre biometria testicular, testosterona, parâmetros seminais e aspectos da espermatogênese em touros Nelore (n = 28). Avaliou-se os testículos dos 10 aos 29 meses de idade. Os touros foram tratados com GnRH (12 a 21 meses) e amostras de sêmen coletadas (25 a 29 meses). Aos 30 meses, os animais foram abatidos. Correlações foram consideradas significativas quando p < 0.05. Concentrações elevadas de testosterona basal ocorreram aos 18 meses, indicativo da puberdade dos touros. Aos 30 meses, os túbulos seminíferosrepresentaram 77,9 ± 3,8% do parênquima testicular e quantificou-se 33,6 ± 8,4 espermátides arredondadas/espermatogônia A1/secção tubular, referente a 47,5% de degeneração celular durante a espermatogênese. Aos 30 meses, peso testicular correlacionou-se com o número de células de Sertoli/ testículo (r = 0,77) e espermátides arredondadas/seção tubular, célula de Sertoli e espermatogônia A1 (r = 0,50 – 0,60). A circunferência escrotal (CE) entre 10 e 29 meses correlacionou-se com a percentagem de túbulos com espermátides (r = 0,42 – 0,59) e número de espermatogônias e espermátides arredondadas/ célula de Sertoli (r = 0,49 – 0,68). Detectou-se correlações entre peso epididimário e número de células de Sertoli/testículo e espermátides arredondadas/célula de Sertoli e espermatogônia A1 (r = 0,51 – 0,61). Testosterona pós-GnRH (17 aos 21 meses) apresentou relação com a CE entre 14 e 29 meses (r = 0,48 – 0,60), peso testicular e epididimário (r = 0,41 – 0,64) e parâmetros da espermatogênese (r = 0,44 – 0,58). Motilidade e vigor espermático (25 aos 29 meses) correlacionaram-se com o número de túbulos com espermátides (r = 0,42 – 0,59) e testosterona pós-GnRH aos 12, 13 e 18 meses (r = 0,46 – 0,57). Portanto, a biometria testicular durante e após a ocorrência dos níveis concentrações elevadas de testosterona é um indicador dos parâmetros quantitativos da espermatogênese em touros pós púberes.