Dependence between behavioural acts and sperm parameters of boars of modern and local breeds of Ukraine

This study aimed to investigate the relationship between behavioural activities and sperm parameters in modern and local breeds of Ukrainian boars. Visual observations were conducted on 30 boars, aged 12 and 24 months, with five boars from each of the following breeds: Large White, Landrace, Ukrainian Meat, Pietrain, intrabreed type of Duroc breed of Ukrainian selection "Steppovyi", and the terminal line "Maxter". Behaviours such as rest, movement, feed, and water intake during 24 hours were recorded. Semen samples were manually collected from each boar and evaluated for quantitative and qualitative indicators of sperm quality and fertilizing capacity according to the "Instructions for Artificial Insemination of Pigs", which included parameters such as ejaculate volume, sperm concentration in the ejaculate, percentage of correctly motile spermatozoa, survival of spermatozoa, and fertilizing ability of boars. The study found that certain behavioural activities significantly influenced the qualitative and quantitative indicators of sperm parameters in boars of different breeds. Specifically, time spent on rest and movement, as well as the index of movement activity (at 12 months of age), significantly (P < 0.05) influenced ejaculate volume, sperm concentration, and the percentage of correctly motile spermatozoa. Moreover, the effect of these behavioural acts on ejaculate volume had a curvilinear character. On the other hand, the survival of spermatozoa and fertilizing ability of boars were mainly determined by their time spent on feed and water intake (at 24 months of age), and the relationship detected in this case was asymptotic.

Importância do plasma seminal na qualidade e preservação do espermatozoide suíno / Importance of seminal plasma in the quality and preservation of boar sperm

Ao preservar o espermatozoide suíno no estado líquido ou criopreservado, os componentes do plasma seminal (PS) contidos nos ejaculados podem alterar a capacidade de fertilização desses gametas. O PS contém substâncias essenciais para a manutenção da viabilidade e fertilidade dos espermatozoides. No entanto, esses componentes podem ser deletérios dependendo da quantidade ou duração do tempo de contato entre a ejaculação e a remoção do PS durante o processamento do sêmen para a conservação na forma refrigerada ou congelada. Foram identificadas substâncias que prejudicam (principal proteína plasmática seminal PSPI) ou melhoram (espermadesina PSP-I) a capacidade de fertilização dos espermatozoides. Dependendo dos cachaços e dos procedimentos de colheita de sêmen, a remoção do PS pode ser benéfica antes da preservação no estado líquido ou criopreservado. Em alguns casos, o PS removido antes da congelação pode ser adicionado de volta ao diluente de descongelamento, com efeitos positivos no sêmen descongelado e na viabilidade do espermatozoide no trato reprodutivo da porca. Neste texto, há um foco nos diferentes efeitos de PS em amostras de sêmen refrigerado e criopreservado de suínos com ênfase em como PS modula a função e morfologia das células espermáticas antes, durante e após a preservação de forma refrigerada ou criopreservada.(AU)

When preserving sperm in the liquid or cryopreserved state, seminal plasma (SP) components within ejaculates can alter fertilizing capacity of these gametes. The SP contains substances essential for maintenance of sperm viability and fertility; however, these components can be deleterious depending on quantity, or duration of time before there is removal of SP from sperm in semen processing. Substances that impair (Major seminal plasma protein PSPI - boar) or improve (e.g., spermadhesin PSP-I - boar) sper- matozoa fertilizing capacity have been identified. Depending on individual males and semen collection procedures, SP removal may be beneficial before preservation in the liquid or cryopreserved state. In some cases, SP that is removed can be added back to thawing extender with there being positive effects in thawed sperm and for sperm viability in the female reproductive tract. In this review article, there is a focus on different effects of SP in samples of cooled and cryopreserved semen from boar with there being emphasis on how SP modulates the function and morphology of sperm cells before, during, and after preservation in the refrigerated or cryopreserved state.(AU)

Cooling of porcine semen in an extender supplemented with isoespintanol / Resfriamento de sêmen suíno em um diluente suplementado com isoespintanol

ABSTRACT: Spermatozoa experience oxidative, osmotic, chemical, and thermal stresses when cooled, which degrade the quality and fertilizing capacity of the cells. Adding antioxidants to the sperm extender mitigates these alterations. This study evaluated the effect of isoespintanol (ISO) on boar semen subjected to cooling. Fifteen ejaculates from five boars (Susscrofadomestica) were extended in Beltsville thawing solution (BTS) supplemented with 0 µM (control), 5 µM (ISO5), 10 µM (ISO10), 15 µM (ISO15), 20 µM (ISO20), 25 µM (ISO25), and 30 µM (ISO30) of ISO, which were then cooled for five days at 16 °C. Sperm kinetics, total motility (TM), and progressive motility (PM) were evaluated every 24 h using an IVOS computer-assisted sperm analysis (CASA) system. On day 1 and day 5 of cooling, a hypoosmotic test, spectrofluorometry, and flow cytometry were performed to evaluate the following: membrane functionality, measured as a function of hypoosmotic swelling (HOS); total antioxidant capacity (TAC); reactive oxygen species (ROS); and mitochondrial membrane potential (Δ¥M). Regression analysis and comparison of means using the Duncan test were performed. The ISO added had a slight impact on sperm motility, as evidenced by a reduction in TM at 24 h of cooling (but not prior) with the addition of 20 µM of ISO. Similarly, no effect of the ISO on the kinetics and functional integrity of the sperm membrane was observed at 96 h of cooling; however, the regression coefficients indicated that the ISO lowered the rate of decrease in sperm motility and the proportion of rapid spermatozoa relative to the concentration of ISO used. The ISO did not affect the TAC of the cooled semen; however, different concentrations of ISO lowered ROS production in the semen after 96 h of cooling. ISO also impacted the Δ¥M of the spermatozoa at 0 h of cooling, increasing the proportion of low Δ¥M cells and decreasing the proportion of high Δ¥M cells. In conclusion, ISO can reduce the loss of quality and oxidative stress occurring in boar semen during cooling and can modulate the mitochondrial activity of sperm.

RESUMO: Durante a refrigeração, os espermatozoides sofrem estresse oxidativo, osmótico, químico e térmico, que diminuem sua qualidade e afetam sua capacidade de fertilização. A adição de antioxidantes ao diluente espermático é uma alternativa para mitigar essas alterações. O objetivo desta pesquisa foi avaliar o efeito do isospintanol (ISO) na refrigeração do sêmen suíno. Quinze ejaculados de cinco varrascos (Sus scrofa domestica) foram diluídos em BTS suplementado com ISO a 0 (controle), 5 (ISO5), 10 (ISO10), 15 (ISO15), 20 (ISO20), 25 (ISO25) e 30 (ISO30) µM e foram refrigerados por cinco dias a 16 °C. A motilidade total (MT), motilidade progressiva (MP) e cinética dos espermatozóides foram avaliadas a cada 24 h com um sistema CASA IVOS. Nos dias um e cinco de refrigeração, foram avaliadas a funcionalidade da membrana, a capacidade antioxidante total (CAT), as espécies reativas de oxigênio (ROS) e o potencial de membrana mitocondrial (Δ¥M), através do teste hiposmótico (HOS), espectrofluorimetría e citometria de fluxo. Foram realizadas análises de regressão e comparação de médias, pelo teste de Duncan. A adição de ISO teve pouca influência na motilidade espermática, apresentando apenas redução na MT em 24 h de refrigeração, devido à adição de 20 µM. Da mesma forma, não foi observada influência de ISO na cinética e integridade funcional da membrana em 96 horas de refrigeração; porém, os coeficientes de regressão mostraram que ISO produziu menor taxa de diminuição da motilidade e proporção de espermatozoides rápidos dependendo da concentração utilizada. ISO não influenciou significativamente na CAT do sêmen refrigerado; entretanto, diferentes concentrações de ISO reduziram a produção de EROs a partir do sêmen após de 96 h de refrigeração. ISO também influenciou o Δ¥M dos espermatozóides em 0 h de refrigeração, com aumento das células de baixo Δ¥M e diminuição das células de alto Δ¥M. Em conclusão, o isospintanol pode reduzir a perda da qualidade e o estresse oxidativo do sêmen suíno durante a refrigeração e pode modular a atividade mitocondrial do esperma.

Relação entre a capacitação espermática e a fertilidade de sêmen criopreservado de bovinos / Relationship between sperm capacitation and fertility in bovine cryopreserved semen

A qualidade do sêmen criopreservado, utilizado na inseminação artificial em tempo fixo (IATF) em bovinos, é um dos principais fatores que impactam sobre a fertilidade, e está relacionada à capacidade de produção espermática dos touros, à criotolerância dos espermatozoides e aos critérios técnicos do processo de criopreservação adotados. Neste sentido, devemos destacar a importância do controle de qualidade das partidas de sêmen antes de serem liberadas para uso na IATF. Nos últimos anos várias técnicas vêm sendo desenvolvidas para avaliar com mais acurácia as partidas de sêmen e evitar o uso daquelas que possam resultar em prejuízos na fertilidade, mas mesmo assim, tem se notado alta variabilidade na taxa de prenhez entre touros e entre partidas de sêmen. Esta divergência se deve ao fato da habilidade fértil do espermatozoide ser multifatorial, ou seja, dependente de diversas características estruturais, morfofuncionais e moleculares. Ademais, os eventos que permitem os espermatozoides passarem por capacitação espermática, um pré-requisito para a fertilidade, têm intrigado os pesquisadores em vista da complexidade dos processos envolvidos e dos efeitos deletérios da criopreservação espermática. Esta revisão tem por objetivo compilar estudos que mostrem a relação entre a capacitação espermática e a fertilidade do sêmen bovino criopreservado, levando em consideração as técnicas de avaliação e os resultados até o momento.(AU)

The quality of cryopreserved semen, used in fixed-time artificial insemination (FTAI) in cattle, is one of the main factors that impact fertility and is related to the sperm production capacity of bulls, sperm cryotolerance, and the technical criteria for cryopreservation. In this sense, we must highlight the importance of quality control of semen batches before commercialization for the FTAI. In recent years, several techniques have progressed to more accurately evaluate semen batches and avoid using those that may result in impaired fertility. However, we still notice a high variability in the pregnancy rate between bulls and between semen batches. This divergence is due to the multifactorial sperm-fertilizing ability, i.e., it depends on several structural, morphofunctional, and molecular characteristics. In addition, the events that allow sperm to undergo sperm capacitation, a prerequisite for fertility, have intrigued researchers due to the complexity of the processes involved and the adverse effects of sperm cryopreservation. This review aims to compile studies that show the relationship between sperm capacitation and fertility in cryopreserved bovine semen, considering the evaluation techniques and results to date.(AU)

DNA methylation level of gene SIRT1 in ram spermatozoa and relationship with fertilizing ability according to breed and age

Background: Effect of the epigenetic factors on the male fertility is well proofed. Sperm acts as a carrier of genetic material, and its DNA methylome can affect maternal pregnancy rate and offspring phenotype. However, the research on the DNA methylation in the spermatozoids of livestock males, in particular rams, is still limited. To best of our knowledge the data about as a global as well as gene specific DNA methylation in ram spermatozoa from different breeds and ages are missed in the scientific literature. The present study was designed to analyze the relationship between methylation levels of the important for spermatogenesis gene SIRT1 in spermatozoa and fertilizing ability of sperm in rams from different breeds and ages. Materials, Methods & Results: The ejaculates of 16 rams from Lacaune, East Friesian and Assaf breeds at age between 18 to 96 months were evaluated. The kinematic parameters of 2 semen samples from each animal were estimated by CASA. The separated spermatozoa were used for DNA extraction followed by bisulfite conversion. The DNA methylation of SIRT1 was detected through quantitative methylation-specific PCR using 2 sets of primers designed specifically for bisulfite-converted DNA sequences to attach methylated and unmethylated sites. The breed and age effect on the gene SIRT1 methylation by ANOVA was estimated. Experimental females included 393 clinically healthy milk ewes (Lacaune, n = 131; East Friesian sheep, n = 100 and Assaf, n = 162) in breeding season. Reproductive performances (conception rate at lambing, lambing percentage and fecundity) of ewes, inseminated by sperm of the investigated rams, were statistically processed. ANOVA showed that the animal breed influences significantly on the level of DNA methylation of gene SIRT1 in ram spermatozoa (P = 0.002) An average value of DNA methylation of SIRT1 in ram sperm from Lacaune breed was significantly higher than in Assaf and East Friesian (81.21 ± 15.1% vs 36.7 ± 14.2% and 38.3 ± 18.6 respectively, P < 0.01). The highest percent of SIRT1 methylation was observed in old animals compared to the young and middle-age. Moderate and strong correlations (r from 0.44 to 0.71, P < 0.05) between the methylation level of the SIRT1 gene in rams' sperm and reproductive parameters of inseminated ewes in all breeds were established. Discussion: Our data are the first message about the effect of breed on the specificity of DNA methylation of gene SIRT1 in ram spermatozoa. These results demonstrated an existence of the sheep breeds with high and low level of DNA methylation of gene SIRT1 in ram sperm. Although the effect of age on the methylation level in sperm is still discussable, our results showed a moderate correlation between age and methylation level of SIRT1 in spermatozoa of rams. Taking into account that DNA methylation in sperm is stabilized with puberty onset and is a heritable epigenetic modification, it can be a promising marker of sperm quality in animal breeding. In all investigated breeds the rams with relatively high level of DNA methylation of gene SIRT1 in spermatozoa (50-68%) demonstrated a high conception rate at lambing (> 70%). In conclusion, the DNA methylation level of the SIRT1 gene in ram spermatozoa is determined by both the breed and the age of the animals and correlates with fertilizing ability of sperm.

Growth performance, reproductive parameters and fertility measures in young Nellore bulls with divergent feed efficiency

The growth, sexual maturity and fertility-related parameters related of young Nellore bulls with divergent residual feed intake (RFI) raised on pasture were evaluated. After classification of 48 young males as low and high RFI (more and less efficient, respectively), the animals were evaluated for growth and reproductive parameters at 28-day intervals from 14.3 to 24.6 months of age. The semen was cryopreserved in the last sampling and fresh and post-thaw semen samples were evaluated. Low RFI bulls exhibited higher initial and final body weight (P < 0.05), but feed intake, body condition score and growth measures evaluated by carcass ultrasound were unaffected by RFI (P > 0.05). The scrotal circumference, sperm concentration, defects, and quality of fresh semen, and ultrasonographic testicular characteristics were unaffected by RFI (P > 0.05). However, velocity parameters such as average path and curvilinear velocities determined by computer-assisted sperm analysis of thawed semen submitted to the rapid thermoresistance test were improved (P < 0.05) in low RFI bulls, but this improvement in quality did not enhance in vitro sperm fertilizing ability. Our results demonstrated significant differences in metabolism and growth performance between bulls of divergent RFI. In addition, there was slight improvement in the semen quality of bulls with low RFI bulls, but this did not enhance in vitro fertilizing ability. Selection of beef bulls for RFI can be performed, which will result in economic benefits by improving the growth performance of the animals without affecting reproductive parameters.(AU)

Effect of ovarian status on reproductive performance in dairy heifers inseminated with sexed semen

Background: The intensive reproductive management in the dairy farms requires inclusion of a large group of replacement heifers in the breeding program for a shorter period. In this aspect, a creation of effective estrus synchronization protocols with timed artificial insemination (TAI) by sexed semen and optimization of the current ones have a crucial role for obtaining high pregnancy rate. These protocols are beneficial, because they led to reduced interval to first AI, lack of need for estrus detection, and allow obtaining a large group of female calves for on time. Because of limited fertilizing potential of sexed spermatozoa this type of semen is applied mainly for heifers, as fertility is higher compared to lactating cows. The main objective of the present study was to investigate the effect of ovarian status on the reproductive performance in dairy heifers subjected to estrus synchronization and timed artificial insemination with sexed semen. Materials, Methods & Results: Forty-eight Holstein healthy heifers separated in 2 groups were subjected to PGF2α-GnRH pre-treatment and Ovsynch or PRID-5-day estrus synchronization protocol and timed artificial insemination (TAI) with sex-sorted semen, staring 6 days after end of the hormonal pre-treatment. The ovarian status (presence of follicles with or not a corpus luteum) of the heifers at the begin of the treatment, on day of TAI and pregnancy rate in different groups were determined and compared. Additionally, the ovarian status at the begin of the treatment, ovarian status and size of preovulatory follicle (PF) on day of TAI and total values for both groups according to reproductive performance (pregnant or non-pregnant) were also analyzed. On day of TAI the animals with PF and a lack of corpus luteum (CL) in both groups were more that those with PF and CL (39.3% and 30% vs. 60.7 % and 70%), with significant (P < 0.05) difference in PRID-5-day group. The pregnancy rate tended to be higher in PRID-5 day than Ovsynch treatment (65% vs. 35.7%). A higher percentage (100% and 67.9%) of the pregnant animals in both treatments had not CL on day of TAI, and the size of the PF (1.58 ± 0.12 cm and 1.64 ± 0.13 cm) was increased (P < 0.05). Similar effects of the ovarian status on reproductive performance were obtained after a comparison of the total values between pregnant and non-pregnant animals. The percentage of heifers with observed PF without CL on day of TAI was significantly greater (P < 0.05) in pregnant compared to non-pregnant group (91.3% vs. 40%). The opposite dependence was determined for the parameter presence of follicles and corpus luteum (8.7% vs. 60%; P < 0.05). Furthermore, the size of the PF measured immediately before TAI was increased in animals became pregnant (1.60 ± 0.12 cm vs. 1.34 ± 0.17 cm; P < 0.05). Discussion: The analysis of the obtained results showed that the ovarian status on day of TAI affects the reproductive performance in dairy heifers subjected to estrus synchronization and timed artificial insemination with sexed semen. Hormonal pre-treatment with onset of PRID-5-day protocol 6 days later and TAI with sex-sorted semen ensure acceptable pregnancy rate. The greater preovulatory follicle and a lack of corpus luteum before insemination provide significantly (P < 0.05) more pregnant animals, compared to the cases when CL is presented. Ultrasound determination of the ovarian function before insemination can be used in selection of heifers for TAI with sex-sorted semen.

Fertility disorders in male dogs

Male dog fertility disorders are usually troublesome and challenging for a practicing veterinarian. It may be generally assumed, that reproductive potential in this species is lower than in farm animals and it is still decreasing. This situation starts to be similar to human medicine, where we observe dramatic drop of reproductive capacity, which resulted in the need of implementation of Assisted Reproductive Technologies (ART). Situation in dogs is more complicated owing the fact, that the use of ART meets many obstacles. Low fertility potential in dogs appears to be the result of variable factors such as: specific criteria of selection for reproduction in which fertility performance in not a priority, lack of periodical obligatory fertility check, species specific predisposition for many reproductive diseases and no age limit for reproductive use of males. Dogs are kept in human environment and exposition for civilizational byproducts influences negatively not only on our health, but also on health our 'minor brothers'. It should be bear in mind, that reproductive organs are very sensitive for environmental factors disrupting homeostatic balance. The decline in male dog fertility over the past decades was proved, with potential link to environmental contaminants (4). They were found in pet foods and were also detected in the sperm and testes of adult dogs causing a detrimental effects on sperm function. Over the 26 years of the study of Lea et al. (4), authors found a decrease in the percentage of normal motile sperm. Between 1988 and 1998, sperm motility declined by 2.5 per cent per year. Then from 2002 to 2014 sperm motility continued to decline at a rate of 1.2% per year. In addition, the male pups had an increased incidence of cryptorchidism. Basics of physiology of reproduction of male dogs. Normally the puberty in males is associated with presence of normal sperm cells in genital organs. It is reached in male dogs at age around 5-6 months. Such a young dog obviously cannot be used for reproduction. Reproductive maturity is associated later, with development of normal sexual behavior and production of sufficient number of normal, fertilizing competent spermatozoa. It corresponds with 12-18 months of animal age. Testicular descent is completed usually before weaning period, but sometimes testicles may reach scrotum later, but never after the end of 6 month of age. That time inguinal canals start to be so narrow, that caudal passing of gonads is unlikely. Male dogs have only one accessory sexual gland - prostate, which produces vast portion of seminal plasma.(AU)

Spirulina platensis extract addition to semen extender enhances cryotolerance and fertilizing potentials of buffalo bull spermatozoa

Abstract The objective of this study was to investigate the effect of Spirulina platensis extract (SPE) addition to the freezing extender on freezability, lipid peroxidation, ultrastructure alterations and fertilizing potentials of frozen-thawed buffalo bull spermatozoa. Semen samples were collected with artificial vagina from five adult fertile bulls and diluted with Tris-base extender containing SPE (1, 5, 10 and 20 μg/mL) or without SPE (control). Diluted semen was cooled to 4 °C throughout one hour and frozen in 0.25 mL straws: prior to being stored in liquid nitrogen. Cryopresreved spermatozoa were assessed for post-thawing sperm motility, viability, acrosomal integrity, ultrastructure changes, antioxidant activities, lipid peroxidation and fertility rate. The current results clearly indicated that adding 10μg/mL SPE to the freezing extender significantly improved (P< 0.05) post-thawing motility and decrease the percentage of acrosomal damage (51.67±6.02% and 16.33±1.46%, respectively) compared with the control (28.33±4.41% and 26.33±1.77%, respectively). Moreover, addition of 10 μg/mL SPE to the semen extender significantly diminished (P< 0.05) MDA concentration (10.66±2.40 nmol/109) compared with the control (22.66±4.26 nmol/109). Therefore, the present results revealed that addition of 10μgl/mL SPE to the freezing extender might improve semen quality and reduce cryodamage of the buffalo bull spermatozoa.

Spirulina platensis extract addition to semen extender enhances cryotolerance and fertilizing potentials of buffalo bull spermatozoa

The objective of this study was to investigate the effect of Spirulina platensis extract (SPE) addition to the freezing extender on freezability, lipid peroxidation, ultrastructure alterations and fertilizing potentials of frozen-thawed buffalo bull spermatozoa. Semen samples were collected with artificial vagina from five adult fertile bulls and diluted with Tris-base extender containing SPE (1, 5, 10 and 20 μg/mL) or without SPE (control). Diluted semen was cooled to 4 °C throughout one hour and frozen in 0.25 mL straws: prior to being stored in liquid nitrogen. Cryopresreved spermatozoa were assessed for post-thawing sperm motility, viability, acrosomal integrity, ultrastructure changes, antioxidant activities, lipid peroxidation and fertility rate. The current results clearly indicated that adding 10μg/mL SPE to the freezing extender significantly improved (P< 0.05) post-thawing motility and decrease the percentage of acrosomal damage (51.67±6.02% and 16.33±1.46%, respectively) compared with the control (28.33±4.41% and 26.33±1.77%, respectively). Moreover, addition of 10 μg/mL SPE to the semen extender significantly diminished (P< 0.05) MDA concentration (10.66±2.40 nmol/109) compared with the control (22.66±4.26 nmol/109). Therefore, the present results revealed that addition of 10μgl/mL SPE to the freezing extender might improve semen quality and reduce cryodamage of the buffalo bull spermatozoa.(AU)

Post-larval Colossoma macropomum (Characiformes, Serrasalmidae) show better performance in excavated than concrete tanks under different feeding strategies

As the global human population increases, the demand for food grows and, consequently, practices such as aquaculture have become more common. Colossoma macropomum (Cuvier, 1818) is a native Amazonian species, considered to be the second most cultivated fish in the country. We compared the development of post-larval C. macropomum of different ages, submitted to combinations of food management on a commercial production scale. Two experiments tested the delivery of i) 55% crude protein feeding, ii) natural feeding by fertilizing the water and iii) a combination of both during hatchery in concrete tanks (10 m 2) or excavated soil-bottom tanks (4502) subjected to distinct fertilization protocols and storage densities. The weight and length of the post-larvae grown in ponds were greater (p < 2.0x10-16) for the mixed treatment, except during the first week of larvae, in which values were similar (p & 8804; 1.76x10-14) to the fertilization treatment. Concrete tanks with fertilization management without feeding were similar to the mixed treatment (p & 8804; 1.38x10-7); however, during the first week of external larvae production, the growth performance under fertilization treatment was superior to the others. Food management in excavated tanks, when compared to the same management performed in concrete tanks, registered higher averages for the productive variables of C. macropomum cultivated at the density of 200 post-larvae m-2 in all evaluated food strategies. It was verified that post-larvae of C. macropomum did not develop well in the first weeks of life when receiving only formulated diets. The increase in natural food availability through fertilization positively influenced the performance of the species, which can remain without feeding until the second week of life.

Post-larval Colossoma macropomum (Characiformes, Serrasalmidae) show better performance in excavated than concrete tanks under different feeding strategies

As the global human population increases, the demand for food grows and, consequently, practices such as aquaculture have become more common. Colossoma macropomum (Cuvier, 1818) is a native Amazonian species, considered to be the second most cultivated fish in the country. We compared the development of post-larval C. macropomum of different ages, submitted to combinations of food management on a commercial production scale. Two experiments tested the delivery of i) 55% crude protein feeding, ii) natural feeding by fertilizing the water and iii) a combination of both during hatchery in concrete tanks (10 m 2) or excavated soil-bottom tanks (4502) subjected to distinct fertilization protocols and storage densities. The weight and length of the post-larvae grown in ponds were greater (p < 2.0x10-16) for the mixed treatment, except during the first week of larvae, in which values were similar (p & 8804; 1.76x10-14) to the fertilization treatment. Concrete tanks with fertilization management without feeding were similar to the mixed treatment (p & 8804; 1.38x10-7); however, during the first week of external larvae production, the growth performance under fertilization treatment was superior to the others. Food management in excavated tanks, when compared to the same management performed in concrete tanks, registered higher averages for the productive variables of C. macropomum cultivated at the density of 200 post-larvae m-2 in all evaluated food strategies. It was verified that post-larvae of C. macropomum did not develop well in the first weeks of life when receiving only formulated diets. The increase in natural food availability through fertilization positively influenced the performance of the species, which can remain without feeding until the second week of life.(AU)

Development, photosynthesis and yield of blueberry cultivar Climax growth with different substrates and nitrogen fertilization under protected cultivation / Fotossíntese, desenvolvimento e produtividade de mirtileiros cultivar ‘Climax cultivados com diferentes substratos e fertilizantes nitrogenados sob cultivo protegido

Organic farming techniques gained popularity recently. Despite this increasing demand, there are still many problems, when comparing nutrient sources in organic and conventional farming systems. The study had as objective to evaluate the development of blueberry plants cultivar Climax under protected cultivation in a substrate with different proportions of organic material and doses of applied mineral N. The blueberry nursery plants Climax were transplanted into plastic pots and kept under protected cultivation. The soil and sand proportions were 40 and 20%, respectively, of the volume capacity of each pot. The remaining 40% were filled with organic material (bovine manure) and sawdust in the proportions of 5 and 35% (S1), 20 and 20% (S2) or 35 and 5% (S3), respectively. The experimental design was in complete randomized blocks, and the treatments were distributed in a 3x3 factorial arrangement, with six replications. The first factor was the different formulations of substrates. The second factor was N fertilization at 0, 10, and 15 g N plant-1. Evaluations of canopy volume, total leaf area, chlorophyll content and gas exchanges were performed six and eighteen months after transplanting. Fruits were harvested according to their ripening. Higher proportions of organic material in the substrate showed a substantial increase on estimated leaf area, canopy volume, chlorophyll content and clear efficiency of carboxylation (A/Ci), especially in plants that was not fertilized with mineral N. The highest yield was reported for the substrate S2, with intermediary amount of organic material, without the application of mineral N fertilizer. Considering agronomic and physiological traits, blueberry plants on the substrate S2 (20% OM) showed the best results, without mineral N fertilizing, becoming viable the organic management system for potted Climax blueberry plants under protected cultivation.(AU)

As técnicas de manejo orgânico ganharam popularidade recentemente. Apesar deste aumento da demanda, ainda há muitos problemas, quando se comparam fontes de nutrientes para manejo orgânico e convencional. O estudo objetivou avaliar o desenvolvimento de mirtileiro cultivar Climax sob cultivo protegido em substrato com diferentes proporções de matéria orgânica e doses de N mineral. As mudas de mirtileiro Climax foram transplantadas para vasos plásticos e mantidas sob cultivo protegido. As proporções de solo e areia foram de 40 e 20%, respectivamente, da capacidade de volume de cada vaso. Os 40% restantes foram preenchidos com matéria orgânica (esterco bovino) e serragem de madeira nas proporções de 5 e 35% (S1), 20 e 20% (S2) e 35 e 5% (S3), respectivamente. O desenho experimental foi em blocos completamente casualizados em esquema fatorial 3x3, com seis repetições. O primeiro fator foram as diferentes formulações de substrato. O segundo fator foi a adubação nitrogenada a 0, 10, e 15 g N planta-1. Avaliações de volume de copa, área foliar total, conteúdo de clorofila e trocas gasosas foram realizadas aos seis e dezoito meses após o transplante. Os frutos foram colhidos de acordo com a maturação. Maiores proporções de matéria orgânica no substrato mostraram um aumento substancial na área foliar estimada, volume de copa, teor de clorofila e na eficiência aparente de carboxilação (A/Ci), especialmente, em plantas que não foram adubadas com N mineral. A maior produtividade foi verificada para o substrato S2, com quantidade intermediária de matéria orgânica, sem a aplicação de fertilizante mineral N. Considerando as características agronômicas e fisiológicas, plantas de mirtileiro no substrato S2 (20% MO) apresentou melhores resultados, sem adubação com N mineral, tornando viável o sistema de manejo orgânico para plantas envasadas de mirtileiro Climax sob cultivo protegido.(AU)

Estresse calórico e reprodução em ovinos: fundamentos e perspectivas tecnológicas / Heat stress on sheep reproduction: fundamentals and technological perspectives

A ovinocultura é uma importante atividade que produz proteínas de alto valor biológico, mas seus ganhos podem ser reduzidos em função do estresse ambiental. Isso reforça a importância de se estudar a relação entre o ambiente térmico e o animal, identificando animais mais adaptados e férteis, e melhores práticas de manejo. O ovino (Ovis aries) é um animal homeotérmico, que mantem sua temperatura corporal em equilíbrio dinâmico. Quando em estresse calórico, os ovinos usam mecanismos sensíveis e latentes para dissipar o calor acumulado, com destaque para o redirecionamento do fluxo sanguíneo, a ofegação e a sudorese. O escroto desempenha importante crucial na termorregulação dos testículos, os quais precisam funcionar sob em até 6,0oC abaixo da temperatura interna corpórea. A hipertermia testicular compromete a espermatogênese, reduz a concentração seminal, a motilidade progressiva e a viabilidade espermática. Ainda, leva a aumento dos defeitos morfológicos espermáticos, na produção de espécies reativas de oxigênio e na fragmentação do DNA espermático, diminuindo a capacidade fecundante. Tecnologias disruptivas para monitoramento do ambiente de produção, da termorregulação e do bem-estar dos animais já são realidade e se encontram em expansão, favorecendo a tomada de decisões em tempo real e o desempenho reprodutivo dos ovinos.

Sheep farming is a relevant activity that provides proteins of high biological value, but its gains can be reduced due to environmental stress. This reinforces the importance of studying the relationship between the thermal environment and the animal, identifying more adapted and fertile animals, and better management practices. Sheep (Ovis aries) are homeothermic animals and thus maintain their body temperature in a state of dynamic balance. Under heat stress, sheep dissipate accumulated heat through sensitive and latent mechanisms, primarily using redirection of blood flow, panting and sweating. The scrotum plays a crucial role in the thermoregulation of the testicles, which need to be maintained up to 6.0oC below the body core temperature. Testicular hyperthermia impairs spermatogenesis, reduces seminal concentration, progressive motility and sperm viability. Furthermore, it leads to an increase in sperm morphological defects, in the production of reactive oxygen species, and in sperm DNA fragmentation, reducing the fertilizing capacity. Disruptive technologies for monitoring the production systems, animal thermoregulation and welfare are already a reality and are expanding, favoring realtime decision making and the reproductive performance of sheep.

Zygoparity in Characidae - the first case of internal fertilization in the teleost cohort Otomorpha

Most teleosts are externally fertilizing, with internal fertilization occurring as a relatively rare event. Until now, Euteleosteomorpha is the only teleost cohort known to undergo internal fertilization. In the teleost cohort Otomorpha, it has been recorded the presence of sperm in the ovaries of some species of Characiformes and Siluriformes, but no fertilized eggs have been found so far in the female reproductive tract. It has been presumed that oocytes can be released into the water with associated spermatozoa and only there becomes fertilized, and the term insemination has been used to characterize the strategy adopted by these fish. Here, we present the discovery of the first case of internal fertilization in the teleost cohort Otomorpha, in Compsura heterura (Characiformes: Characidae). In the course of spawning, the eggs form the perivitelline space and the animal and vegetative poles within the ovaries, evidencing oocyte fertilization. The newly spawned eggs then continue to form the animal and vegetative poles and increase the perivitelline space. These eggs are in the zygotic stage. These data indicate that fertilized eggs are only retained for a short period, providing evidence that C. heterura is a zygoparous fish.(AU)

A maioria dos teleósteos são espécies com fecundação externa, sendo a fecundação interna um evento relativamente raro. Até o momento, Euteleosteomorpha é a única coorte de teleósteos conhecida com espécies de fecundação interna. Na coorte de teleósteos Otomorpha, tem sido registrada a presença de esperma nos ovários de algumas espécies de Characiformes e Siluriformes, porém nenhum ovo fecundado foi encontrado até agora no trato reprodutor feminino. Presume-se que os oócitos possam ser liberados na água associados aos espermatozoides e que somente lá são fecundados, e o termo inseminação tem sido empregado para caracterizar a estratégia adotada por esses peixes. Apresentamos aqui a descoberta do primeiro caso de fecundação interna na coorte de teleósteos Otomorpha, em Compsura heterura (Characiformes: Characidae). Durante a desova, os ovos formam o espaço perivitelino e os polos animal e vegetal dentro dos ovários, evidenciando a fecundação interna. Os ovos recém-desovados continuam a formação dos polos animal e vegetal e aumentam o espaço perivitelino. Esses ovos estão na fase zigótica. Estes dados indicam que os ovos fertilizados são retidos por um curto período, fornecendo evidências de que C. heterura é um peixe zigóparo.(AU)

Zygoparity in Characidae - the first case of internal fertilization in the teleost cohort Otomorpha

Most teleosts are externally fertilizing, with internal fertilization occurring as a relatively rare event. Until now, Euteleosteomorpha is the only teleost cohort known to undergo internal fertilization. In the teleost cohort Otomorpha, it has been recorded the presence of sperm in the ovaries of some species of Characiformes and Siluriformes, but no fertilized eggs have been found so far in the female reproductive tract. It has been presumed that oocytes can be released into the water with associated spermatozoa and only there becomes fertilized, and the term insemination has been used to characterize the strategy adopted by these fish. Here, we present the discovery of the first case of internal fertilization in the teleost cohort Otomorpha, in Compsura heterura (Characiformes: Characidae). In the course of spawning, the eggs form the perivitelline space and the animal and vegetative poles within the ovaries, evidencing oocyte fertilization. The newly spawned eggs then continue to form the animal and vegetative poles and increase the perivitelline space. These eggs are in the zygotic stage. These data indicate that fertilized eggs are only retained for a short period, providing evidence that C. heterura is a zygoparous fish.(AU)

A maioria dos teleósteos são espécies com fecundação externa, sendo a fecundação interna um evento relativamente raro. Até o momento, Euteleosteomorpha é a única coorte de teleósteos conhecida com espécies de fecundação interna. Na coorte de teleósteos Otomorpha, tem sido registrada a presença de esperma nos ovários de algumas espécies de Characiformes e Siluriformes, porém nenhum ovo fecundado foi encontrado até agora no trato reprodutor feminino. Presume-se que os oócitos possam ser liberados na água associados aos espermatozoides e que somente lá são fecundados, e o termo inseminação tem sido empregado para caracterizar a estratégia adotada por esses peixes. Apresentamos aqui a descoberta do primeiro caso de fecundação interna na coorte de teleósteos Otomorpha, em Compsura heterura (Characiformes: Characidae). Durante a desova, os ovos formam o espaço perivitelino e os polos animal e vegetal dentro dos ovários, evidenciando a fecundação interna. Os ovos recém-desovados continuam a formação dos polos animal e vegetal e aumentam o espaço perivitelino. Esses ovos estão na fase zigótica. Estes dados indicam que os ovos fertilizados são retidos por um curto período, fornecendo evidências de que C. heterura é um peixe zigóparo.(AU)

Decision-making on the optimum timing for nitrogen fertilization on sugarcane ratoon

Low efficiency of nitrogen from fertilizers is a major concern worldwide, threatening the sustainability of sugarcane production. The N use efficiency (NUE) by sugarcane can be improved by adopting better fertilizing management practices, reducing environmental impacts. This work evaluated the effects of varying N rates and time of application on stalks and sugar yield in ratoon harvested early in the crop season. The experimental design was a randomized block in a 2 × 4 factorial design and a control (no N) with five replications, including two application times (45 or 90 DAH – days after harvest) and four N rates (50, 100, 150, or 200 kg N ha−1). The time of N fertilizer application promoted differences in stalk yield, as the cumulative yield of two harvests was increased by 8 % (15 Mg ha−1) at 45 DAH when compared to the application at 90 DAH. The application performed at 45 DAH augmented sugar yield by 10 % (2.8 Mg ha−1 of sugar) in relation to 90 DAH. The N rates that promoted the highest sugarcane yield were, respectively, 122 and 144 kg N ha−1 in the first and second crop cycles. The average economical rates obtained for the first and second agricultural cycles were, respectively, 104 and 127 kg N ha−1, demonstrating that the gains by applying high amounts of fertilizers (rates above 150 kg N ha−1) may not cover the investment.

Decision-making on the optimum timing for nitrogen fertilization on sugarcane ratoon

Low efficiency of nitrogen from fertilizers is a major concern worldwide, threatening the sustainability of sugarcane production. The N use efficiency (NUE) by sugarcane can be improved by adopting better fertilizing management practices, reducing environmental impacts. This work evaluated the effects of varying N rates and time of application on stalks and sugar yield in ratoon harvested early in the crop season. The experimental design was a randomized block in a 2 × 4 factorial design and a control (no N) with five replications, including two application times (45 or 90 DAH days after harvest) and four N rates (50, 100, 150, or 200 kg N ha−1). The time of N fertilizer application promoted differences in stalk yield, as the cumulative yield of two harvests was increased by 8 % (15 Mg ha−1) at 45 DAH when compared to the application at 90 DAH. The application performed at 45 DAH augmented sugar yield by 10 % (2.8 Mg ha−1 of sugar) in relation to 90 DAH. The N rates that promoted the highest sugarcane yield were, respectively, 122 and 144 kg N ha−1 in the first and second crop cycles. The average economical rates obtained for the first and second agricultural cycles were, respectively, 104 and 127 kg N ha−1, demonstrating that the gains by applying high amounts of fertilizers (rates above 150 kg N ha−1) may not cover the investment.(AU)

Capacidade fecundante do sêmen congelado de Prochilodus brevis / Fertilizing capacity of the cryopreserved sperm of Prochilodus brevis

Background: Seminal cryopreservation is a technique that optimizes aquacultural production, as it requires less breedingand enables reproduction outside of the breeding season. This technique also helps to preserve species, thus reducing thepressure on the natural stocks. Several studies have sought to develop freezing protocols that result in semen of a goodquality. However, some studies do not evaluate the ability of frozen semen to produce viable larvae. Therefore, the aimof this study was to verify the fertilizing capacity of the frozen semen of Prochilodus brevis.Materials, Methods & Results: Semen from twenty adult males of the Brazilian bocachico was collected and evaluatedto establish the total motility, curvilinear velocity, straight linear velocity, average path velocity, membrane integrity, pH,and concentration. Six pools were formed, each of which was diluted in a freezing medium containing 5% glucose with10% dimethyl sulfoxide (DMSO) or 5% glucose with 10% methyl glycol (MG). The samples were loaded into 0.25 mLFrench straws, frozen in a dry shipper, and stored in a liquid nitrogen canister. The semen was then thawed and evaluatedto establish the total motility, curvilinear velocity, straight linear velocity, average path velocity, and membrane integrity.For the fertilization test, four females were used. The oocytes from each female were divided into three batches and fertilized with either fresh or cryopreserved semen. The rates of fertilization, hatching, and larval survival were then measured.Data were expressed as the mean ± standard deviation and analyzed using SAS (2002). The frozen semen with glucose +DMSO was significantly higher (P < 0.001) than the frozen semen with glucose + MG, in all seminal quality parametersevaluated (63.95 ± 15.88% and 25.36 ± 3.53% for the motility, 36.38 ± 7.02 μm.s-1 and 20.45 ± 2.84 μm.s-1 for the curvilinear velocity, 19.26 ± 2.74 μm.s-1 and...

Capacidade fecundante do sêmen congelado de Prochilodus brevis / Fertilizing capacity of the cryopreserved sperm of Prochilodus brevis

Background: Seminal cryopreservation is a technique that optimizes aquacultural production, as it requires less breedingand enables reproduction outside of the breeding season. This technique also helps to preserve species, thus reducing thepressure on the natural stocks. Several studies have sought to develop freezing protocols that result in semen of a goodquality. However, some studies do not evaluate the ability of frozen semen to produce viable larvae. Therefore, the aimof this study was to verify the fertilizing capacity of the frozen semen of Prochilodus brevis.Materials, Methods & Results: Semen from twenty adult males of the Brazilian bocachico was collected and evaluatedto establish the total motility, curvilinear velocity, straight linear velocity, average path velocity, membrane integrity, pH,and concentration. Six pools were formed, each of which was diluted in a freezing medium containing 5% glucose with10% dimethyl sulfoxide (DMSO) or 5% glucose with 10% methyl glycol (MG). The samples were loaded into 0.25 mLFrench straws, frozen in a dry shipper, and stored in a liquid nitrogen canister. The semen was then thawed and evaluatedto establish the total motility, curvilinear velocity, straight linear velocity, average path velocity, and membrane integrity.For the fertilization test, four females were used. The oocytes from each female were divided into three batches and fertilized with either fresh or cryopreserved semen. The rates of fertilization, hatching, and larval survival were then measured.Data were expressed as the mean ± standard deviation and analyzed using SAS (2002). The frozen semen with glucose +DMSO was significantly higher (P < 0.001) than the frozen semen with glucose + MG, in all seminal quality parametersevaluated (63.95 ± 15.88% and 25.36 ± 3.53% for the motility, 36.38 ± 7.02 μm.s-1 and 20.45 ± 2.84 μm.s-1 for the curvilinear velocity, 19.26 ± 2.74 μm.s-1 and...(AU)