Exogenous melatonin ameliorates embryo-maternal cross-talk in early pregnancy in sheep.

In Brief: Melatonin plays a crucial role in enhancing reproductive performance in small ruminants. This paper reveals the effects of exogenous melatonin on the placental and endometrial rearrangement in early pregnancy in sheep.

Abstract: Early pregnancy losses cause 25% of pregnancy failures in small ruminants because of asynchrony between conceptus and uterine signals.

Mouthbrooding.

Osmar Luiz and colleagues introduce the parental care strategy of some vertebrates to brood eggs in their mouths.

Densitometric analysis of GnRH and IBA1 immunocytochemistry in the basal ventromedial hypothalamus of the ewe.

Gonadotropin releasing hormone (GnRH) synthesis and secretion regulates seasonal fertility. In the brain, the distribution of GnRH-positive neurons is diffuse, hindering efforts to monitor variations in its cellular and tissue levels. Here, we aim at assessing GnRH immunoreactivity in nuclei responsible for seasonal fertility regulation (SFR) within the posterior, anterior, and preoptic areas of the basal hypothalamus during estrous in ewes.

Differential effect of melatonin on ram spermatozoa depending on the allelic variant of the polymorphism of the gene, incubation medium and season.

Context The Rsa I polymorphism of the melatonin receptor MTNR1A gene affects seasonal reproduction in sheep, but its effect on ram spermatozoa and their response to melatonin is unknown. Aims This study aims to evaluate whether Rsa I polymorphism of the MTNR1A gene influences the response of ram spermatozoa to in vitro added melatonin. Methods Spermatozoa from rams carrying different Rsa I allelic variants were incubated with melatonin in a TALP medium or a capacitation-triggering medium during the reproductive and non-reproductive seasons.

Physical separation and reduction of contact duration with sexually hyperactive bucks decrease testosterone concentrations and sexual behaviour in bucks in sexual rest.

Sexually hyperactive bucks are more efficient than sexually hypoactive bucks in stimulating testosterone secretion and sexual behaviour in other bucks in seasonal sexual rest by the phenomenon that we called the "buck-to-buck effect". Here, we determined whether physical separation and reduction of the duration of contact with the sexually hyperactive bucks would modify those parameters in sexually hypoactive bucks exposed to the "buck-to-buck effect". Bucks were subjected to natural day length throughout the study; this was the sexually hypoactive group.

Genotyping of rams based on melatonin receptor 1A gene polymorphisms: a tool in sire selection?

Context Several polymorphisms in the melatonin receptor 1A gene (MTNR1A ) have been related to reproductive performance in ovine. Aims To investigate the effect of the Rsa I and Mnl I polymorphisms on ram seminal quality. Methods Eighteen Rasa Aragonesa rams were genotyped for the Rsa I (C/C, C/T, T/T) and Mnl I (G/G, G/A, A/A) allelic variants of the MTNR1A gene.

Hair from sexually active bucks strongly activates olfactory sensory inputs but fails to trigger early first ovulation in prepubescent does.

Early exposure of does to sexually active bucks triggers early puberty onset correlating with neuroendocrine changes. However, the sensory pathways that are stimulated by the male are still unknown. Here, we assessed whether responses to olfactory stimuli are modulated by social experience (exposure to males or not) and/or endocrine status (prepubescent or pubescent).

The Effect of By-Pass Linseed Oil Supplementation on the Maternal Antioxidant System during the Embryo-Maternal Recognition Period in Ewes.

This study analyzed the effects of dietary supplementation with by-pass linseed oil (LO; rich in α-linolenic acid) on maternal antioxidant systems at Days 14 and 16 of pregnancy in Sarda ewes. This trial used sixteen dry ewes. Eight ewes (CT group) were fed with a control diet without LO, and eight ewes (LO group) were fed with a diet supplemented with LO (10.

The melatonin system is expressed in the ovine uterus: effect of the day of the oestrous cycle and undernutrition.

Context: Melatonin influences female reproduction, but expression of the melatonin system has not been characterised in the ovine uterus.

Aims: We aimed to determine whether synthesising enzymes (arylalkylamine N-acetyltransferase (AANAT) and N-acetylserotonin-O-methyltransferase (ASMT)), melatonin receptors 1 and 2 (MT1 and MT2), and catabolising enzymes (myeloperoxidase (MPO) and indoleamine 2,3-dioxygenase 1 and 2 (IDO1 and 2)), are expressed in the ovine uterus, and if they are influenced by the oestrous cycle (Experiment 1) or by undernutrition (Experiment 2).

Methods: In Experiment 1, gene and protein expression was determined in sheep endometrium samples collected on days 0 (oestrus), 5, 10 and 14 of the oestrous cycle.

Male-induced early puberty correlates with the maturation of arcuate nucleus kisspeptin neurons in does.

In goats, early exposure of spring-born females to sexually active bucks induces an early puberty onset assessed by the first ovulation. This effect is found when females are continuously exposed well before the male breeding season starting in September. The first aim of this study was to evaluate whether a shortened exposure of females to males could also lead to early puberty.

Improvement of the Seminal Characteristics in Rams Using Agri-Food By-Products Rich in Phytomelatonin.

The aim of this study was to evaluate the effect of a phytomelatonin-rich diet, including by-products from the food industry, on ram sperm quality and seminal plasma composition. Melatonin content in several by-products before and after in vitro ruminal and abomasal digestion was determined by HPLC-ESI-MS/MS. Finally, 20% of a mix of grape pulp with pomegranate and tomato pomaces was included in the rams' diet, constituting the phytomelatonin-rich diet.

Anatomy of hypothalamic and diencephalic nuclei involved in seasonal fertility regulation in ewes.

In this study, we describe in detail the anatomy of nuclei involved in seasonal fertility regulation (SFR) in ewes. For this purpose, the intergeniculate leaflet of the visual thalamus, the caudal hypothalamic arcuate nucleus, and suprachiasmatic, paraventricular and supraoptic nuclei of the rostral hypothalamus were morphometrically and qualitatively analyzed in Nissl-stained serial sections, in the three anatomical planes. In addition, data were collected on calcium-binding proteins and cell phenotypes after immunostaining alternate serial sections for calretinin, parvalbumin and calbindin.

Use of Acheta domesticus meal as a full soybean substitute in the feeding of slow-growing chicks.

Sustainable poultry meat production involves the use of slow-growing chick strains and the utilization of new protein sources as an alternative to the current monopoly of soybean meal. In this scenario, a study was conducted to assess the effect of replacing soybean meal with domestic cricket (Acheta domesticus) meal on the developing cycle of slow-growing chicks. To this end, a total of 128 one-day-old male chicks (Colorield) were randomly assigned into 16 experimental units, each consisting of 8 chicks, which in turn were grouped into 2 groups fed isoproteic and isoenergetic diets in which the protein source differed: the control group (C) fed soybean meal and the Acheta group (AD) fed Acheta domesticus insect meal as the main protein source.

Effect of Strategic Supplementation of Dietary By-Pass Linseed Oil on Fertility and Milk Quality in Sarda Ewes.

The aim of the present study was to assess whether the strategic supplementation of bypass LO can enhance reproductive indexes—fertility, lambing rate, and prolificacy—in dairy Sarda ewes at the end of lactation. To assess whether LO supplementation leads to the adsorptions of PUFAs and their subsequent utilization by the body tissues, milk composition and fatty acid content were analyzed. Forty-eight ewes were assigned to the following groups: the control group (CT; N = 24), fed with a control diet without LO; and the treatment group (LO; N = 24), fed with a diet supplemented with LO (10.

Metabolic memory determines oviductal gene expression of underfed ewes during early gestation.

Our aim was to investigate the oviduct environment by studying oviduct gene expression after undernutrition in day-5 pregnant ewes with different initial (i) BCS, and its association with the number of embryos recovered. Thirty-six ewes were divided into 2 groups with different iBCS: iBCS ≥2.75 (n = 19; high, H) and iBCS ≤2.

Exposure of rams in sexual rest to sexually activated males in spring increases plasma LH and testosterone concentrations.

Eight stimulating rams, and twelve stimulated rams, were used to determine whether a similar endocrine response to the introduction of sexually active males in spring in a flock of ewes is observed in a flock of rams. The stimulating rams (n = 4) were induced into a sexually active state by exposure to 2 months of long days (16 h light/d) (15 December-15 February). At the end of the long-day period, rams were returned to the natural photoperiod.

The combination of melatonin implants and prostaglandin F2α improves lamb production in a late-autumn mating season.

To determine the effect of the combination of melatonin implants and prostaglandin (PG) F2α on reproductive performance in the late breeding season (Dec at the northern hemisphere), 500 Lacaune ewes were divided into four groups. On day 0 (7 Nov), 150 ewes were treated with a melatonin (M) implant. From that group, 64 ewes (M + 1PGF group) were injected with 10-mg prostaglandin (PG) F2α 34 d after melatonin implantation (11 Dec).

Measuring lamb activity during lactation by actigraphy.

Twenty-two lambs were used to determine their locomotor activity during lactation, and its circadian rhythm, based on data collected by actigraphy; the relationships among lambs were also measured calculating their proximity and distance. Lambs were fitted with Bluetooth-enabled (BT) accelerometers during weeks 1 and 4 of age, and data were downloaded as activity counts at 1-min intervals (Vector Magnitude, VM). Sensors were programmed as receivers and as beacons of the BT signal to calculate proximity (min/h) and distance (m) to another lamb.

Efficiency of Artificial Insemination at Natural Estrus in Organic Ewes.

Hormonal treatments used in the artificial insemination (AI) of sheep can cause several physiological problems that can affect negatively fertility and animal health; however, AI protocols based on the detection of natural estrus offer a more sustainable option and can achieve high fertility. In this study, an AI protocol at natural estrus in organic sheep was performed. In the first phase (AI protocol development), 125 ewes were exocervically inseminated, and their fertility was assessed based on the following factors: number of AI, physiological state, body condition, estrus detection-AI interval, and vaginal fluids in cervix.

Sexually active male goats stimulate the endocrine and sexual activities of other males in seasonal sexual rest through the "buck-to-buck effect".

Male goats rendered sexually active by exposure to a photoperiodic treatment are more efficient than untreated goats in stimulating LH secretion and ovulation in seasonally anestrous goats. This phenomenon is called the "male effect." Here, we determined whether sexually active bucks are able to stimulate the endocrine and sexual activities of other bucks in seasonal sexual rest through the phenomenon that we called the "buck-to-buck effect.

Sex and male breeding state predict intraspecific trait variation in mouth-brooding fishes.

Sex-specific reproductive roles contribute to sexual dimorphic morphological trait variations. In uniparental mouth-brooding fishes, the mouth performs a reproductive function in addition to its key roles in feeding and respiration, resulting in the potential for sex-specific functional performance trade-offs. Trait differences related to parental care may occur when the individual matures or be restricted to periods when the parent is mouth-brooding.

Effects of Implanting Exogenous Melatonin 40 Days before Lambing on Milk and Colostrum Quality.

The effects of exogenous melatonin implanted before lambing on the quality of colostrum and milk yield were quantified in 715 ewes. Forty days before lambing, 246 ewes (1M) received a melatonin implant; another 137 ewes (2M) received two implants, and the remaining 332 ewes (C) did not receive an implant (control). Milk analysis was based on individual monthly milk samplings (June, July, and August) after lambing.

Diverse parentage relationships in paternal mouthbrooding fishes.

While mouthbrooding is not an uncommon parental care strategy in fishes, paternal mouthbrooding only occurs in eight fish families and is little studied. The high cost of paternal mouthbrooding to the male implies a low risk of investment in another male's offspring but genetic parentage patterns are poorly known for paternal mouthbrooders. Here, we used single-nucleotide polymorphism genetic data to investigate parentage relationships of broods of two mouthbrooders of northern Australian rivers, mouth almighty and blue catfish .

Comparison of four strategies of ram management in a semen collection centre.

Thirty Merino rams were used to determine the effect of four management systems of rams on semen quality during the anoestrous season. Animals were divided into four groups: Artificial-Photoperiod group (AP; n = 8), which were isolated from females and exposed to artificial long days (16 hr/d) from 1 Feb to 15 Mar; Natural-Photoperiod (NP; n = 8), isolated from females and exposed to the natural photoperiod throughout the experiment; Oestrous-Ewe group (EE; n = 7), housed in a pen adjacent to another pen that housed three ewes in oestrus, and Anestric-Ewe group (AE; n = 7), housed adjacent to another pen that housed three ovariectomized ewes. From 20 Mar to the end of May (10 weeks), semen samples were collected weekly, and blood samples were collected to determine plasma testosterone concentrations.

Performance of Slow-Growing Chickens Fed with Larval Meal as a Full Replacement for Soybean Meal.

Insect larval meal is an increasingly common protein source in poultry systems. In this study, the effect of replacing soybean meal with larval meal on the performance of slow-growing chickens was assessed. A total of 128 one-day-old chickens () were randomly divided into a control group (C) ( = 64), fed with soybean meal, and an experimental group (TM) ( = 64), fed with larvae meal.