Performance In Mammals Research Articles

Bioactive Compounds Protect Mammalian Reproductive Cells from Xenobiotics and Heat Stress-Induced Oxidative Distress via Nrf2 Signaling Activation: A Narrative Review.

Oxidative stress occurs when there is an imbalance between the production of reactive oxygen species (ROS) and the body's antioxidant defenses. It poses a significant threat to the physiological function of reproductive cells. Factors such as xenobiotics and heat can worsen this stress, leading to cellular damage and apoptosis, ultimately decreasing reproductive efficiency. The nuclear factor erythroid 2-related factor 2 (Nrf2) signaling pathway plays a crucial role in defending against oxidative stress and protecting reproductive cells via enhancing antioxidant responses. Dysregulation of Nrf2 signaling has been associated with infertility and suboptimal reproductive performance in mammals. Recent advancements in therapeutic interventions have underscored the critical role of Nrf2 in mitigating oxidative damage and restoring the functional integrity of reproductive cells. In this narrative review, we delineate the harmful effects of heat and xenobiotic-induced oxidative stress on reproductive cells and explain how Nrf2 signaling provides protection against these challenges. Recent studies have shown that activating the Nrf2 signaling pathway using various bioactive compounds can ameliorate heat stress and xenobiotic-induced oxidative distress and apoptosis in mammalian reproductive cells. By comprehensively analyzing the existing literature, we propose Nrf2 as a key therapeutic target for mitigating oxidative damage and apoptosis in reproductive cells caused by exposure to xenobiotic exposure and heat stress. Additionally, based on the synthesis of these findings, we discuss the potential of therapies focused on the Nrf2 signaling pathway to improve mammalian reproductive efficiency.

Does the number of functional olfactory receptor genes predict olfactory sensitivity and discrimination performance in mammals?

The number of functional genes coding for olfactory receptors differs markedly between species and has repeatedly been suggested to be predictive of a species' olfactory capabilities. To test this assumption, we compiled a database of all published olfactory detection threshold values in mammals and used three sets of data on olfactory discrimination performance that employed the same structurally related monomolecular odour pairs with different mammal species. We extracted the number of functional olfactory receptor genes of the 20 mammal species for which we found data on olfactory sensitivity and/or olfactory discrimination performance from the Chordata Olfactory Receptor Database. We found that the overall olfactory detection thresholds significantly correlate with the number of functional olfactory receptor genes. Similarly, the overall proportion of successfully discriminated monomolecular odour pairs significantly correlates with the number of functional olfactory receptor genes. These results provide the first statistically robust evidence for the relationship between olfactory capabilities and their genomics correlates. However, when analysed individually, of the 44 monomolecular odourants for which data on olfactory sensitivity from at least five mammal species are available, only five yielded a significant correlation between olfactory detection thresholds and the number of functional olfactory receptors genes. Also, for the olfactory discrimination performance, no significant correlation was found for any of the 74 relationships between the proportion of successfully discriminated monomolecular odour pairs and the number of functional olfactory receptor genes. While only a rather limited amount of data on olfactory detection thresholds and olfactory discrimination scores in a rather limited number of mammal species is available so far, we conclude that the number of functional olfactory receptor genes may be a predictor of olfactory sensitivity and discrimination performance in mammals.

Lipopolysaccharide accelerates tryptophan degradation in the ovary and the derivative kynurenine disturbs hormone biosynthesis and reproductive performance

Lipopolysaccharide (LPS), also known as endotoxin, is a component of the outer membrane of gram-negative bacteria. LPS is released into the surrounding environment during bacterial death and lysis. Due to its chemical and thermal stability, LPS can be detected anywhere and easily exposed to humans and animals. Previous studies have shown that LPS causes hormonal imbalances, ovarian failure, and infertility in mammals. However, the potential mechanisms remain unclear. In this study, we investigated the effects and mechanisms of LPS on tryptophan degradation, both in vivo and in vitro. The effects of kynurenine, a tryptophan derivative, on granulosa cell function and reproductive performance were explored. Results showed that p38, NF-κB, and JNK signaling pathways were involved in LPS-induced Ido1 expressions and kynurenine accumulation. Furthermore, the kynurenine decreased estradiol production, but increased granulosa cell proliferation. In vivo, experiments showed that kynurenine decreased estradiol and FSH production and inhibited ovulation and corpus luteum formation. Additionally, pregnancy and offspring survival rates decreased considerably after kynurenine treatment. Our findings suggest that kynurenine accumulation disrupts hormone secretion, ovulation, corpus luteal formation, and reproductive performance in mammals.

Whole genome-wide analysis of DEP family members in sheep (Ovis aries) reveals their potential roles in regulating lactation

BackgroundSheep milk is an attractive nutritional and functional food source. Some Dishevelled, Egl-10 and pleckstrin (DEP) domain-containing proteins can regulate lactation performance in mammals. However, systematic study of the role of sheep DEP family members in regulating lactation is currently lacking. This study aimed to reveal the roles of sheep DEP family members in lactation by exploring their genetic characteristics and functional features at the whole genome-wide level.ResultsTwenty DEP family members were identified in the sheep genome, and they can be divided into four major groups. Ka/Ks calculations suggest that the purifying selection is the main pressure acting on DEP genes. In the late pregnancy and lactation periods, the expression levels of eight DEP genes exhibited significant differences in the mammary gland. In addition, nutritional conditions have a great influence on the expression of DEP family members, and the DEP gene family underwent more expansion than the average gene family in the early stages of biological evolution. The Mirrortree assays indicated that the DEP family members coevolved in biological evolution.ConclusionsOur research provides a better understanding of the characters of the DEP domain-containing protein family and their potential roles in regulating lactation in sheep. Moreover, these results of our study may contribute to the genetic improvement of milk performance in dairy sheep breed.Graphical

Foraging on anthropogenic food predicts problem-solving skills in a seabird

Species and populations with greater cognitive performance are more successful at adapting to changing habitats. Accordingly, urban species and populations often outperform their rural counterparts on problem-solving tests. Paradoxically, urban foraging also might be detrimental to the development and integrity of animals' brains because anthropogenic foods often lack essential nutrients such as the long-chain omega-3 fatty acids eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA), which are important for cognitive performance in mammals and possibly birds. We tested whether urbanization or consumption of EPA and DHA are associated with problem-solving abilities in ring-billed gulls, a seabird that historically exploited marine environments rich in omega-3 fatty acids but now also thrives in urban centres. Using incubating adults nesting across a range of rural to urban colonies with equal access to the ocean, we tested whether urban gulls preferentially consumed anthropogenic food while rural nesters relied on marine organisms. As we expected individual variation in foraging habits within nesting location, we characterized each captured gulls' diet using stable isotope and fatty acid analyses of their red blood cells. To test their problem-solving abilities, we presented the sampled birds with a horizontal rendition of the string-pull test, a foraging puzzle often used in animal cognitive studies. The isotopic and fatty acid profiles of urban nesters indicated a diet comprising primarily anthropogenic food, whereas the profiles of rural nesters indicated a high reliance on marine organisms. Despite the gulls' degree of access to urban foraging habitat not predicting solving success, birds with biochemical profiles reflecting anthropogenic food (less DHA and a higher carbon-13 ratio in their red blood cells) had a greater probability of solving the string-pull test. These results suggest that experience foraging on anthropogenic food is the main explanatory factor leading to successful problem-solving, while regular consumption of omega-3s during incubation appears inconsequential.

Integration of terbium isotopes into modern nuclear medicine

The review examines the clinical role of terbium isotopes in the context of their integration into modern routine practice in nuclear medicine. Low toxicity, combined with an optimal half-life and elimination time from the body, makes them very promising not only in the therapeutic sense, but also in the issue of diagnostic imaging of tumors. When performing PET /CT and SPECT/CT imaging with 152Tb and 155Tb isotopes on cancer patients, high diagnostic information values were obtained. It should be noted that in the context of 152Tb, the phase of clinical trials on patients has already been completed, according to the results of which this radionuclide has demonstrated its potential. SPECT with 155Tb provides excellent imaging performance in mammals, even with low levels of injected radioactivity, which makes it promising for use in humans. Key words: terbium, nuclear medicine, single-photon emission tomography, positron emission tomography

Swimming exercise enhances brain plasticity in fish.

It is well-established that sustained exercise training can enhance brain plasticity and boost cognitive performance in mammals, but this phenomenon has not received much attention in fish. The aim of this study was to determine whether sustained swimming exercise can enhance brain plasticity in juvenile Atlantic salmon. Brain plasticity was assessed by both mapping the whole telencephalon transcriptome and conducting telencephalic region-specific microdissections on target genes. We found that 1772 transcripts were differentially expressed between the exercise and control groups. Gene ontology (GO) analysis identified 195 and 272 GO categories with a significant overrepresentation of up- or downregulated transcripts, respectively. A multitude of these GO categories was associated with neuronal excitability, neuronal signalling, cell proliferation and neurite outgrowth (i.e. cognition-related neuronal markers). Additionally, we found an increase in proliferating cell nuclear antigen (pcna) after both three and eight weeks of exercise in the equivalent to the hippocampus in fish. Furthermore, the expression of the neural plasticity markers synaptotagmin (syt) and brain-derived neurotrophic factor (bdnf) were also increased due to exercise in the equivalent to the lateral septum in fish. In conclusion, this is the first time that swimming exercise has been directly linked to increased telencephalic neurogenesis and neural plasticity in a teleost, and our results pave the way for future studies on exercise-induced neuroplasticity in fish.

Effectiveness of citrulline and N-carbamoyl glutamate as arginine precursors on reproductive performance in mammals: A systematic review.

The use of functional nutrients has been proposed to reduce the occurrence of intrauterine growth retardation in animals at birth in several mammalian species. The objective of this study was to verify the effectiveness of citrulline and N-carbamylglutamate (NCG) dietary supplementation as arginine precursors for mammalian species, and the effects on fetal development through a systematic review. The search for studies was performed during August 2018 in the PubMed, ISI Web of Science, Science Direct, and Scopus databases. The literature search was conducted using “arginine precursor”, “citrulline”, or “N-carbamylglutamate” as keywords, combined with “gestation”, “pregnancy”, “fetus”, “newborn”, or “reproduction”. Studies in which arginine precursors were evaluated in gestating mammals and their effects on parameters related to the intrauterine development of the conceptus were selected. Of 1,379 articles, 18 were selected, primarily based on the title and the abstract. Supplementation with NCG (0.5 g to 2 g/kg of feed) increased maternal plasma arginine concentrations in all studies that evaluated this variable. Fetal number increased in 55.56% of the studies that evaluated it, and fetal weight increased in the majority (62.5%) of the studies evaluating this variable. By supplementing citrulline, only fetal weight was improved, with an increase in maternal plasma arginine in 40% of the studies. In conclusion, N-carbamoyl glutamate seems to be an arginine precursor more effective than L-citrulline during gestation; however, both precursors, beside L-Arginine, should be evaluated in similar conditions to confirm the existence of specific particularities such as periods and levels of supplementation, which need to be considered for different species of animals. The supplementation of NCG increases arginine concentrations in maternal plasma, thus improving mammalian reproductive efficiency and fetal development, mainly by promoting higher birth weight.

Dietary Daidzein Supplementation During Pregnancy Facilitates Fetal Growth in Rats.

Daidzein, a natural isoflavone with estrogen-like activity, has been implicated in the regulation of reproductive performance in mammals. However, little is known about the molecular mechanisms involved. Here, the effects and potential mechanisms of daidzein supplementation on fetal growth in rats have been explored. Thirty-six pregnant Sprague-Dawley rats are assigned to receive either an AIN-93M diet or an AIN-93M diet supplemented with 50mgkg-1 daidzein. Blood, placental, and fetus samples were collected on day 15 of gestation. It is shown that daidzein significantly improves the rat reproductive performance, which is associated with a higher fetus number, and the weight of the fetus and placenta (p<0.05). Daidzein also increases the maternal serum estrogen and leptin concentrations, and the activity of superoxide dismutase (SOD) (p<0.05). Notably, the isobaric tags for relative and absolute quantification (iTRAQ)-based proteomics analysis identifies 43 differentially expressed (DE) proteins in the placenta upon daidzein supplementation (p<0.05). Interestingly, critical proteins involved in amino acid transport and metabolism, embryonic development, ubiquitination processes, and immune responses are upregulated in the daidzein group (p<0.05). These results not only indicate a beneficial effect of daidzein supplementation on reproductive performance but also offer potential mechanisms behind daidzein-facilitated fetal growth in rats.

Comparison of decoding performance between spike and local field potential signals during goal-directed decision-making task of pigeons

Both spike and local field potential (LFP) signals are two of the most important candidate signals for neural decoding. At present there are numerous studies on their decoding performance in mammals, but the decoding performance in birds is still not clear. We analyzed the decoding performance of both signals recorded from nidopallium caudolaterale area in six pigeons during the goal-directed decision-making task using the decoding algorithm combining leave-one-out and k-nearest neighbor (LOO- kNN). And the influence of the parameters, include the number of channels, the position and size of decoding window, and the nearest neighbor k value, on the decoding performance was also studied. The results in this study have shown that the two signals can effectively decode the movement intention of pigeons during the this task, but in contrast, the decoding performance of LFP signal is higher than that of spike signal and it is less affected by the number of channels. The best decoding window is in the second half of the goal-directed decision-making process, and the optimal decoding window size of LFP signal (0.3 s) is shorter than that of spike signal (1 s). For the LOO- kNN algorithm, the accuracy is inversely proportional to the k value. The smaller the k value is, the larger the accuracy of decoding is. The results in this study will help to parse the neural information processing mechanism of brain and also have reference value for brain-computer interface.

Differentially expressed miRNA-210 during follicular-luteal transition regulates pre-ovulatory granulosa cell function targeting HRas and EFNA3.

Ovarian folliculogenesis, ovulation, and luteinization are an important prerequisite for fertility performance in mammals. Spatial and temporal key factors and proteins for their regulation are well known. Recent advancement in the field of molecular biology led to the discovery of another class of gene regulators, microRNA (miRNA). Previous studies on profiling of miRNA in buffalo ovaries revealed that miRNA-210 (miR-210) is differently expressed in follicular-luteal transition. Therefore, the present study was planned to ascertain the role of miR-210 in buffalo granulosa cells. Cultured granulosa cells were transfected with miR-210 mimic. Effect of overexpression of miR-210 was analyzed on granulosa cell marker genes (CYP19A1 and PCNA) which were significantly downregulated (P < 0.05). Further, target genes of miR-210 were screened using Target Scan software v7.1 and a list of 37 genes with cumulative weight context score (CWCS) > 0.5 was sorted followed by their functional annotation and network analyses using PANTHER and STRING software. Bioinformatics analyses identified HRas gene as a potential hub gene of miR-210 targeted genes. HRas has been shown to be involved in diverse biological pathways regulating ovarian functions. An expression analysis of HRas was further validated both in vitro and in vivo. EFNA3 (EFHRIN-A3), another identified target of miR-210 known to be involved in angiogenesis, was also downregulated in miR-210 transfected granulosa cells. In conclusion, the present study demonstrated that miR-210 can regulate granulosa cell function at preovulatory stage through HRas and EFNA3. Further studies are needed to find the mechanism how miR-210 regulates the granulosa cells function through these targets.

Jaw-Dropping: Functional Variation in the Digastric Muscle in Bats.

Diet and feeding behavior in mammals is strongly linked to the morphology of their feeding apparatus. Cranio-muscular morphology determines how wide, forcefully, and quickly the jaw can be opened or closed, which limits the size and material properties of the foods that a mammal can eat. Most studies of feeding performance in mammals have focused on skull form and jaw muscles involved in generating bite force, but few explore how jaw abduction is related to feeding performance. In this study, we explored how the morphology of the digastric muscle, the primary jaw abducting muscle in mammals, and its jaw lever mechanics are related to diet in morphologically diverse noctilionoid bats. Results showed that insectivorous bats have strong digastric muscles associated with proportionally long jaws, which suggests these species can open their jaws quickly and powerfully during prey capture and chewing. Short snouted frugivorous bats exhibit traits that would enable them to open their jaws proportionally wider to accommodate the large fruits that they commonly feed on. Our results support the hypothesis that digastric muscle and jaw morphology are correlated with diet in bats, and that our results may also apply to other groups of mammals. Anat Rec, 301:279-290, 2018. © 2018 Wiley Periodicals, Inc.

Local Klotho Enhances Neuronal Progenitor Proliferation in the Adult Hippocampus.

Klotho is an aging-related protein associated with hippocampal cognitive performance in mammals. Klotho regulates progenitor cell proliferation in non-neuronal tissues, but its role in adult hippocampal neurogenesis (AHN) has not been explored. Klotho expression in the adult mouse hippocampus was examined by immunofluorescence and polymerase chain reaction. AHN was evaluated in the hippocampus of klotho knock-out mice (KO), klotho KO/vitamin D-receptor mutant mice, and in a model of local klotho hippocampal knockdown. The recombinant Klotho effect on proliferation was measured in mouse-derived hippocampal neural progenitor cells. Hippocampal-dependent memory was assessed by a dry-land version of the Morris water maze. Klotho was expressed in the granular cell layer of the adult Dentate Gyrus. AHN was increased in klotho KO mice, but not in klotho KO/vitamin D-receptor mutant mice. Inversely, local downregulation of hippocampal Klotho diminished AHN. Recombinant Klotho increased the proliferation rate of neural progenitors. Downregulation of hippocampal Klotho correlated with a decreased performance in hippocampal-dependent memory. These results suggest that Klotho directly participates in regulating AHN. Our observations indicate that Klotho promotes proliferation, AHN and hippocampal-dependent cognition. Increased neurogenesis in klotho KO mice may be secondary to the activation of other pathways altered in the model, such as vitamin D.

66 DEVELOPMENTAL HEALTH ASSESSMENT OF OFFSPRING PRODUCED FROM MAGNETIC NANOPARTICLES USING NEAR INFRARED ANALYSIS OF PLASMA

In vitro fertilization is optimized when there is a homogenous population of viable spermatozoa, not subjected toxic waste products of apoptotic cells. In a previous study, we developed a “nanopurification” technique to magnetically target and remove non-viable spermatozoa from a boar insemination dose. Nanopurified semen has successfully been studied with IVF in swine and bovine but lacks health data regarding offspring produced from exposed semen. Developmental health performance in mammals is typically assessed through measurements of immune related biomolecules in plasma (e.g. immunoglobulins), quantifying each variable with a specific analytical assay. Recent developments in aqueous based near infrared spectroscopy (NIR), aquaphotomics, have been shown to distinguish reproductive stages (e.g. oestrus, diestrus) in blood serum. Thus, application of aquaphotomics may be ideal for analysis of offspring resulting from fertilization with nanopurified semen, using serum or plasma. Our study objective was to identify holistic differences in blood plasma by characterising NIR spectral profiles in offspring produced from nanopurified semen. Extended boar semen doses were mixed with or without specific nanoparticles to target non-viable spermatozoa. Semen doses were exposed to an electromagnetic field, noninvasively separating non-viable spermatozoa from the insemination dose. Six gilts were bred with (n = 3) or without (n = 3) nanopurified semen. Following birth and weaning, 20 offspring of equal sexes were randomly selected from control and nanopurified litters (10/group) for growth and developmental measurements up until market weight. Blood plasma was collected from offspring at market weight for NIR analysis. Spectral data were collected with a quartz cuvette and ASD FieldSpec® 3 spectrophotometer (ASD Inc., Boulder, CO, USA). Chemometric analysis (Unscrambler® X version 10.4; CAMO Software, Oslo, Norway) included a Savistsky-Golay 1st and 2nd derivative for detection of distinct spectral features. Principal component analysis and partial least-squares block-discrimination were used to examine treatment effects, in a blind experiment. Plasma spectral profiles from control and nanopurified offspring contained 6 shared peaks at 1360, 1373, 1402, 1404, 1422, and 1428 nm. Principle components 1 and 2 accounted for 96.26% of the total variance, with no separation of principal component analysis scores for plasma spectra between groups. Partial least-squares discriminant analysis metrics (slope = 0.026, SECV = 0.52) and Students t-test showed no significant difference (P = 0.57) between groups. Results indicate blood plasma content is not influenced in nanopurified offspring when compared with the control. In addition, solute NIR has shown to be a valuable promising tool for assessing complex aqueous solutions in swine. Further effects on growth and development from offspring born from nanopurified continue to be investigated. This work was supported by USDA-ARS Biophotonics Initiative grant #58–6402–3-018.

Previous motor activity affects the transition from uncertainty to decision making in snails.

One of the most widely accepted benefits of enhanced physical activity is an improvement in the symptoms of depression, including the facilitation of decision making. Up until now, these effects have been shown in rodents and humans only. Little is known about their evolutionary origin or biological basis, and the underlying cellular mechanisms also remain relatively elusive. Here, we demonstrate for the first time that preceding motor activity accelerates decision making in an invertebrate, the pond snail Lymnaea stagnalis To investigate decision making in a novel environment, snails, which normally live in water, were placed on a flat dry surface to simulate the potentially threatening consequence of being in an arid environment. This stimulus initiated two distinct phases in snail behaviour: slow circular movements, followed by intense locomotion in a chosen direction. The first phase was prolonged when the test arena was symmetrically lit, compared with one with an apparent gradient of light. However, forced muscular locomotion for 2h prior to the test promoted the transition from random circular motions to a directional crawl, accompanied by an increase in crawling speed but with no effect on the choice of direction. Intense locomotion for 2 h also produced a strong excitatory effect on the activity of serotonergic neurons in L. stagnalis Our results suggest that the beneficial effects of physical exercise on cognitive performance in mammals might have deep roots in evolution, granting the opportunity to unravel the origins of such effects at the single-neuron and network levels.

The roles of kisspeptin revisited: inside and outside the hypothalamus.

Kisspeptin, encoded by KISS1/Kiss1 gene, is now considered a master regulator of reproductive functions in mammals owing to its involvement in the direct activation of gonadotropin-releasing hormone (GnRH) neurons after binding to its cognate receptor, GPR54. Ever since the discovery of kisspeptin, intensive studies on hypothalamic expression of KISS1/Kiss1 and on physiological roles of hypothalamic kisspeptin neurons have provided clues as to how the brain controls sexual maturation at the onset of puberty and subsequent reproductive performance in mammals. Additionally, emerging evidence indicates the potential involvement of extra-hypothalamic kisspeptin in reproductive functions. Here, we summarize data regarding kisspeptin inside and outside the hypothalamus and revisit the physiological roles of central and peripheral kisspeptins in the reproductive functions of mammals.

Polymorphism identification in BMP15 and GDF9 genes and their association with egg production in chickens

1. Mutations in growth differentiation factor 9 (GDF9) and bone morphogenetic protein 15 (BMP15) are significantly associated with reproductive performance in mammals and the objective of the present study was to identify polymorphic sites and elucidate the association between genotypes in BMP15 and GDF9 and egg production.2. Polymorphisms in BMP15 exon1 and GDF9 exon2 were detected by DNA sequencing and PCR-RFLP. Three SNPs were detected in each of BMP15 (A111G, C231T and C34T) and GDF9 (G593A, T824C and C896T). C34T leads to the substitution of Leu by Phe, which was predicted to affect protein function.3. Results of the association analysis indicated that C34T had an effect on total egg production at 300 d of age (EN) and age at first laying (AFE). G593A affected EN and both C231T and C896T influenced AFE. The TGC1TGC1 diplotype in BMP15 had the highest EN.4. In conclusion, EN may be significantly improved by marker-assisted selection of the BMP15 genotypes in maternal lines of Shaobo hens.

KNDy neuron as a gatekeeper of puberty onset

Hypothalamo-pituitary-gonadal axis has been recognized as a functional unit orchestrating reproductive performance in mammals. The mechanism governing puberty onset, however, is still one of the great mysteries of biology. The present article reviews previous studies over the last century, which gradually elucidated the brain mechanism controlling puberty onset in mammals along with the discovery of gonadotrophins and the gonadotrophin-releasing hormone and the establishment of the concept for the hypothalamo-pituitary-gonadal axis. The discovery of kisspeptin and subsequent progress of neuroendocrinology in the last decade has resulted in much greater understanding of the way the brain governs puberty onset in mammals.

Development and Validation of a Universal Measurement System for Measuring the Performance of Mammals

Exercise wheels for mammals are commonly used as test systems in many medical research areas. Studies may be related to many different areas such as vitamins, hormones (as dopamine), and physical endurance. As research develops the scope and size of the studies increase and the requirements of the test system might change. In order to conduct the experiments effectively, there is a need to increase the number of test stations, and the test station may also be required to handle physically larger mammals. This study presents and validates a wireless system for endurance tests. The system was validated on mice and humans. It is scalable, and can be expandable up to 254 test stations. In the case of the exercise wheel with mice, the ADEA system was used as a reference. The initial validation was done by comparing the activity measured by both systems in mice with different hormone dopamine levels. The correlation coefficients between the systems estimated activity levels were in the range from 0.916 to 0.967. The new system enables quantitative measurements of the activity level using standard SI units (meters and seconds, respectively). In the validation with humans, runners were clocked by the system and manually. The lowest correlation coefficient obtained during these measurements was 0.864. Thus, both applications showed a high correlation with conventional methods.

Factores nutricionales que interfieren en el desempeño reproductivo de la hembra bovina

La nutrición es el principal factor que influye en el desempeño reproductivo en mamíferos. Las funciones reproductivas como ciclicidad estral y el inicio de la gestación son funciones de escasa prioridad dentro de la escala de direccionamiento de nutrientes.; Estas funciones solo serán activadas cuando la demanda de nutrientes para mantenimiento, crecimiento y reserva haya sido superada. Conocer los factores nutricionales que interfieren en la reproducción de la hembra, es de vital importancia para posibles decisiones a ser tomadas dentro de los sistemas de producción ganaderos. En esta revisión se describen conceptos generales sobre los factores nutricionales que afectan la reproducción de la hembra bovina, como los efectos de la nutrición materna sobre el desempeño de las crías, los factores nutricionales que afectan la aparición de la pubertad en las novillas y como el consumo de nutrientes y la condición corporal de las hembras interfiere en el desempeño reproductivo de las mismas.