1. Investigación

The present experiment aimed at determining whether the timing of the maternal recognition of pregnancy (MRP) was specific to individual mares by determining when luteostasis, a failure to return to oestrus, reliably occurred in individuals following embryo reduction. Singleton (n = 150) and synchronous twin pregnancies (n = 9) were reduced in 10 individuals (5–29 reductions/mare) at pre-determined time points within days 10 (n = 20), 11 (n = 65), 12 (n = 47), 13 (n = 12) or 14 (n = 15) of pregnancy. Prior to embryo reduction, the vesicle diameter was measured in 71% (106/150) of the singleton pregnancies. The interovulatory interval (IOI) was recorded on 78 occasions in seven of the mares in either non-pregnant cycles (n = 37) or those in which luteolysis followed embryo reduction (n = 41). The earliest time post-ovulation at which the embryo reduction resulted in luteostasis in an individual was 252 h (mid-Day 10). Consistency in luteostasis following embryo reduction showed individual variation between mares (272–344 h). Binary logistic regression analysis showed an individual mare effect (p < 0.001) and an effect of the interval post-ovulation at which embryo reduction was undertaken (p < 0.001). However, there was no significant effect of vesicle diameter at the time of embryo reduction (p = 0.099), nor a singleton or twin pregnancy (p = 0.993), on the dependent of luteolysis or luteostasis. The median IOI between individual mares varied significantly (p < 0.05) but was not correlated to the timing of MRP. The timing of MRP varied between the mares but was repeatable in each individual. The factors and mechanisms underlying the individuality in the timing of MRP were not determined and warrant further study.

Para llevar a cabo el diagnóstico de gestación en el ganado bovino, se debe utilizar un método preciso, seguro, económico y que se pueda realizar de manera temprana. Aunque varias técnicas están actualmente disponibles en el mercado, otras siguen todavía en desarrollo, siendo posibles herramientas diagnósticas a tener en cuenta en un futuro. Por ello, el presente trabajo tiene como objetivo hacer una revisión sobre las diversas técnicas de diagnóstico de gestación (DG) y su potencial uso a nivel comercial, tanto en el presente como en el futuro, de la ganadería bovina. Los métodos directos para el DG, como son la palpación directa o la ecografía del tracto reproductor vía transrectal, siguen siendo los más empleados en la actualidad durante el control gestacional en el ganado vacuno. Son técnicas diagnósticas con buenos resultados y son interesantes a nivel económico, pero son herramientas invasivas y requieren una cierta experiencia por parte del técnico que las realiza. En general, se aplican a partir de la 3ª-4ª semana posterior a la inseminación artificial. Por otro lado, los métodos indirectos de DG son menos invasivos que los directos. Mediante este tipo de diagnósticos vía indirecta se puede detectar la presencia o ausencia de un embrión, sin visualizar directamente estructuras gestacionales. Existen métodos indirectos basados en signos clínicos, como la vigilancia del retorno al estro, así como técnicas indirectas bioquímicas, que permiten evaluar mediante el uso de kits rápidos ciertas sustancias como la progesterona (P4) o las Glicoproteínas Asociadas a la Gestación (GPAG), producidas durante la gestación de forma temprana. Otras técnicas novedosas y prometedoras, pero que todavía se encuentran en desarrollo, son la evaluación de moléculas como el interferón tau (IFNτ), los micro-ARN (miARN) y/o los Factores de Gestación Temprana (FGT).

The study aimed to evaluate the effects of different stages of lactation (0 to >300 d) and pregnancy (0 to >180 d) on serum amyloid A (SAA), C-reactive protein (CRP), glucose, total cholesterol (TCho), and triglyceride (TG) concentrations in dairy cows of different breeds. Thus, 40 healthy multiparous cows (10 Holstein, 10 Simmental, 10 Brown, and 10 Modicana) were randomly selected, and blood samples were collected once every 60 d for 1 year. Overall, SAA and CRP serum concentrations progressively increased and became more variable along the lactation, peaking at >240–300 d, and then decreased in the last period (>300 d). Along pregnancy, SAA and CRP initially increased, with the highest concentrations at >60–120 d, and then decreased until the last phase of pregnancy (>180 d). However, lactation and gestation phases did not significantly affect SAA and CRP when all the cows were analyzed together. A significant and positive correlation was observed between SAA and CRP both along lactation (r D 0:89; p<0:0001) and pregnancy (r D 0:91; p<0:0001). Breeds only showed differences in CRP levels along gestation (p D 0:0102), due to a peak registered at 0–60 d in Holstein cows. In pregnant cows, glucose was positively correlated with SAA (r D 0:43; p D 0:0017) and CRP (r D 0:42; p D 0:0019). Hence, these significant and positive relationships reflect the physiological adaptations of the dairy cows along both gestational and lactational dynamics, suggesting that these proteins may also be involved in non-pathological processes. In this perspective, this study established that the obtained response markedly varies among healthy individuals along lactation and gestation and thus that the physiological range of acute-phase proteins (APPs) is wide; this makes it difficult to use these proteins as a marker of different physiological reproductive and productive periods.

The last third of gestation is a period of high energy and protein demand for the dam to support fetal growth and the following onset of lactation. Methionine is an essential amino acid that contributes to protein formation, fetal development, and milk synthesis; thus, is likely to have positive effects on the weight and size of the newborn and, afterward, milk yield and milk composition, which may improve growth patterns of the progeny. To test these hypotheses, we used 60 pregnant multiparous Alpine goats with similar live weights and gestational ages (~Day 100 of pregnancy; Mean SD; 1410 14 days old and 50.4 6.6 kg) and were separated into two groups: control and supplemented with the delivery. Treatments were T-MET (n = 30; received 1% herbal methionine Optimethione® dry matter based on from Day 100 of the pregnancy to delivery) or T-CTL (n = 30; served as the control and did not receive methionine). The methionine powder provided individual supplementation and was adjusted every week as the live weight and dry matter intake changed. At birth, the weight, body mass index (BMI), birth type, and sex of the kids were determined. Subsequently, the progeny was weighed weekly up to weaning. Two weeks after parturition, the milk composition was recorded weekly, and the milk yield was recorded monthly. The maternal live weight at the start (Mean SEM; T-CTL: 50.5 1.1 vs. T-MET: 50.3 1.3 kg) and end (T-CTL: 54.2 1.3 vs. T-MET: 52.8 1.4 kg) of the experiment did not differ statistically among treatments (p > 0.05); however, daily live weight changes tended to differ between groups (T-CTL: 73 10 vs. T-MET: 51 7 g day􀀀1; p = 0.06). The birth weight (T-CTL: 3.1 0.1 vs. TMET: 3.5 0.1 kg; p < 0.001), daily live weight change (T-CTL: 121 6 vs. T-MET: 141 6 g day􀀀1; p < 0.01), and weaning weight (T-CTL: 8.3 0.2 vs. T-MET: 9.3 0.3 kg; p < 0.01) differed between treatments. The BMI at birth (T-CTL: 0.28 0.01 vs. T-MET: 0.3 0.01 units kg m􀀀2; p < 0.01) and at weaning (T-CTL: 0.85 0.1 kg vs. T-MET: 1.00 0.06 units kg m􀀀2; p < 0.05) differed between treatments. Milk components (protein, fat, lactose, and solids non-fat) and milk yield were similar between treatments (p > 0.05). It is concluded that the inclusion of methionine in the maternal goat diet during the last third of gestation increases the birth and growth variables of the progeny but without significant influence on the milk yield and composition.

Hypoxemia and oxidative stress, resulting in intrauterine growth restriction (IUGR) in undernourished twin sheep pregnancies, has been described in near-term studies. Our aim was to evaluate if the counteractive effects of maternal nutritional or antioxidant supplementation on the fetal redox status were evident before the accelerated fetal growth phase. Forty twin-bearing ewes grazing on natural Patagonian prairie were randomly assigned to four groups (n = 10 each; P: control ewes consuming mainly natural pasture; P+A: pasture plus antioxidants; P+C: pasture plus concentrate; P+A+C: pasture plus antioxidants and concentrate). Daily herbal antioxidants were supplemented in a feedstuff concentrate as a premix from day 35 until day 100 of gestation, when fetal venous cord blood samples and biometric measurements were obtained via cesarean section. The fetuses from group P were clearly hypoxemic. An analysis of variance showed that maternal antioxidant supplementation showed a trend of increased PO2, SatHb, and Ht, effects not observed in P+C fetuses. Antioxidants decreased the fetal MDA concentration (p < 0.05). Fetal TAC was increased by the antioxidants and concentrate (p < 0.05). Antioxidant supplementation showed a trend to increase fetal body weight but not biometry. The results suggest that negative effects of oxidative stress occur earlier than the overt growth arrest, and the maternal administration of antioxidants may constitute a good nutritional strategy for the early prevention of IUGR.

In some species, female steroid hormones modify the profile of acute phase proteins (APPs) during the estrous cycle and pregnancy, according to the ovulation, embryonic implantation and placental development; however, nowadays there’s no experimental evidence for equine species. Objectives of this study were: to compare the serum amyloid A (SAA), haptoglobin (Hp) and C-reactive protein (CRP) concentrations between cyclic and pregnant mares, and to analyze the influence of estradiol-17β (E2) during estrous cycle or estrone sulfate (E1) during pregnancy, and progesterone (P4) on these proteins to assess their potential role to identify the cyclicity or pregnancy in Spanish mares. Blood samples were taken from 20 Purebred Spanish mares on the day of ovulation (day 0), on days +5 and +16 post-ovulation, and then, monthly during the whole pregnancy. SAA, Hp and CRP did not change between day 0, +5 and +16 post-ovulation days. P4 concentrations were significantly higher on day +16 than on days +5 and 0; and E2 concentrations were significantly higher on day 0 than day +5. On the other hand, pregnancy was characterized by a progressive increase in the Hp, variable modifications of E1 and P4 concentrations, without changes in SAA and CRP. The absence of significant differences in the APPs between days 0, +5 and +16, suggested that these proteins cannot be used as biomarkers of diagnosis of heat or preg- nancy in Spanish mares, at least early, since the Hp later increases during the gestation. Nevertheless, it is possible to use them for comparative purposes with other equine breeds, as supervisor instrument of health status in breeding females as diagnostic tools to monitor pregnancy’s development and/or subclinical reproductive inflammations, that could lead to the early embryonic death.

La fructosa, presente en la sacarosa y el jarabe de maíz rico en fructosa, se ha relacionado con el desarrollo de diabetes, obesidad y síndrome metabólico, trastornos que han alcanzado proporciones epidémicas a nivel mundial. La nutrición materna constituye uno de los factores causales que modulan el riesgo de padecer enfermedades metabólicas en la edad adulta, mediante la “programación fetal”. En un primer estudio se evaluó la administración de fructosa a descendientes de madres-fructosa o glucosa a los 8 meses de edad. En la descendencia macho adulta el consumo de fructosa aumenta la producción de FGF21, principalmente en los descendientes de madres-fructosa, y la dieta materna determina la función de FGF21 tanto en el metabolismo lipídico como en el estrés oxidativo. En la descendencia hembra, el consumo de fructosa provoca una reducción en la producción hepática de H2S, siendo más evidente en las descendentes de madres-fructosa. En el segundo procedimiento se estudió la descendencia macho de madres control o fructosa de 3 meses de edad. La ingesta materna de fructosa influye en la absorción intestinal de ácidos biliares y triglicéridos cuando se somete a la descendencia macho al consumo de tagatosa. La asociación de fructosa y colesterol condujo a una dislipemia acusada de forma independiente de la dieta materna. Además, el consumo de fructosa provocó una reducción en la producción de H2S exclusivamente en el hígado, efecto que agravado al asociar fructosa y colesterol y que no se observó tras la administración de tagatosa. Finalmente quisimos evaluar si se producía una transmisión de generación en generación de las alteraciones metabólicas asociadas al consumo de fructosa durante la gestación. Así, la descendencia hebra preñada descendiente de madres-fructosa presentaba un fenotipo programado, presentando una alterada respuesta a insulina y leptina, dislipemia y esteatosis. Es más, estos cambios se observaban también en sus fetos.

El envejecimiento y la gestación son dos situaciones fisiológicas que cursan con metainflamación y resistencia a la insulina. La pleiotrofina regula el recambio lipídico, la homeostasis energética, la sensibilidad a la insulina y la plasticidad del tejido adiposo. Nuestra hipótesis es que la pleiotrofina podría modular las adaptaciones metabólicas del hígado durante el último tercio de la gestación y durante el envejecimiento. Para corroborar nuestra hipótesis empleamos ratones hembra Knock out para pleiotrofina y sus respectivos controles (Wild type) a los 3, 6, 12 y 15 meses de edad (modelo de envejecimiento) o a los 18 días de gestación. La deleción de pleiotrofina se asocia a un menor peso corporal y del hígado, una menor acumulación de lípidos hepáticos e intolerancia a la glucosa. Asimismo, observamos un papel regulatorio de la pleiotrofina en la biogénesis y función mitocondriales en el hígado y un papel de la glicerol quinasa en la regulación de la homeostasis glucídica durante la gestación. La pleiotrofina es esencial en el mantenimiento de la metabolismo lipídico y glucídico hepático y la deleción de pleiotrofina evita la acumulación ectópica de grasa en el hígado y protege frente al desarrollo de esteatosis.

The effects of a combined supplementation with herbal antioxidants during pregnancy on reproductive traits and piglet performance (number of live, dead, and mummified newborns and litter weight at birth and individual body weight at both birth and weaning) were assessed in a total of 1027 sows (504 treated and 523 control females) kept under commercial breeding conditions. The supplementation increased the number of live-born piglets (13.64 0.11 vs. 12.96 0.13 in the controls; p = 0.001) and the total litter weight, decreasing the incidence of low-weight piglets without affecting the number of stillbirths and mummified newborns. Such an effect was modulated by the number of parity and the supplementation, with supplementation increasing significantly the number of living newborns in the first, second, sixth, and seventh parities (0.87, 1.10, 1.49, and 2.51 additional piglets, respectively; p < 0.05). The evaluation of plasma vitamin concentration and biomarkers of oxidative stress (total antioxidant capacity, TAC, and malondialdehyde concentration, MDA) performed in a subset of farrowing sows and their lighter and heavier piglets showed that plasma levels of both vitamins were significantly higher in the piglets than in their mothers (p < 0.05 for vitamin C and p < 0.005 for vitamin E), with antioxidant supplementation increasing significantly such concentrations. Concomitantly, there were no differences in maternal TAC but significantly higher values in piglets from supplemented sows (p < 0.05). On the other hand, supplementation decreased plasma MDA levels both in the sows and their piglets (p < 0.05). Finally, the piglets from supplemented mothers showed a trend for a higher weaning weight (p = 0.066) and, specifically, piglets with birth weights above 1 kg showed a 7.4% higher weaning weight (p = 0.024). Hence, the results of the present study, with high robustness and translational value by offering data from more than 1000 pregnancies under standard breeding conditions, supports that maternal supplementation with herbal antioxidants during pregnancy significantly improves reproductive efficiency, litter traits, and piglet performance.

Maternal supplementation with antioxidants and n-3 PUFAs may be a promising strategy to reduce the risk of intrauterine growth restriction and preterm delivery, which may diminish the appearance of low-birth-neonates. A previous studies showed beneficial outcomes of the combination of hydroxytyrosol and linoleic acid, but there is no data of its prenatal effects. The present study aimed to determine the possible prenatal implications of such maternal supplementation at prenatal stages in swine, a model of IUGR pregnancies. Results showed effects on litter size, with treated sows having larger litters and, therefore, smaller fetuses. However, the brain/head weight ratio showed a positive effect of the treatment in development, as well as in some other major organs like lungs, spleen, or kidneys. On the other hand, treated piglets showed better glycemic and lipidemic profiles, which could explain postnatal effects. However, further research on the implications of the treatment on litter size and prenatal and postnatal development must be done before practical recommendation can be given.