Regulatory roles of leptin in reproduction and metabolism: a comparative review

The effects of saline water consumption on sperm parameters, testicular histopathology, hormonal and antioxidants concentrations in Barki Rams

The study aimed to assess the effects of water salinity on the sperm parameters, levels of cortisol, LH, FSH, testosterone and antioxidants as well as the testes' histopathology in Barki rams. Fifteen healthy Barki rams (1-1.5 years) were divided into three equal depending on the type of drinking water for nine months. The rams in the tap water group (TW, water that contained 350 ppm of total dissolved salts (TDS). Males in the high saline water group (HSW) were permitted to consume high saline water with 8,934 ppm TDS, whereas those in the second group were permitted to have moderately saline water (MSW, 4,557 ppm TDS). High salt concentration in drinking water had adverse effect on sperm viability, morphology and sperm cell concertation. Nitric oxide and malondialdehyde concentrations in blood were significantly higher in the MSW and HSW groups than in TW. There was a significant decrease in glutathione concentration as well as superoxide dismutase activity in TDS and HSW. Cortisol was most highly concentrated in the HSW, next in the MSW, and least in TW. The testosterone, LH, and FSH concentrations in the HSW and MSW groups were significantly lower than in TW. As the salt concentration in drinking water increases, damage to testicular tissue. The MSW group demonstrating vacuolation of lining epithelial cells with pyknotic nuclei in the epididymis and necrosis and desquamation of spermatogenic cells in seminiferous tubules while HSW group displaying desquamated necrotic cells and giant cell formation in the epididymis, as well as damage to some of the seminiferous tubules and showed congestion, vacuolation of spermatogenic epithelium of seminiferous tubules, and desquamated necrotic spermatogenic epithelium. In conclusion, the salinity of the water has detrimental impacts on the sperm morphology, viability and concentration, hormones and antioxidant levels in Barki rams.

Metabolic imprinting in beef calves supplemented with creep feeding on performance, reproductive efficiency and metabolome profile

This experiment evaluated the influence of creep feeding supplementation on productive and reproductive performance and on serum metabolome profile in Nelore (Bos indicus) heifers. Female calves were assigned to treatments: Creep (n = 190), with ad libitum access to a nutritional supplement from 70 to 220 days after birth, or Control (n = 140), without supplementation. After weaning (Day 220), both groups followed the same pasture and nutritional management. Body weight (BW) and backfat thickness (BFAT) were measured over time. Blood samples were collected at 220 and 360 days for LC-MS/MS targeted metabolomics. On day 408, during the synchronization timed artificial insemination (TAI) protocol, reproductive status (RS: diameter of uterine horn and largest follicle, and presence of CL) was assessed. Creep feeding increased BW and BFAT at weaning, but no differences in BW, BFAT, or RS after weaning were observed. Nonetheless, the pregnancy per AI (P/AI) for 1st service was 28.9% higher in the Creep group. On day 220, 11 significant metabolites influenced five metabolic pathways: Glucose-alanine cycle, alanine, glutathione, phenylalanine and tyrosine metabolism, and urea cycle. On day 360, 14 significant metabolites influenced eight metabolic pathways: Malate-aspartate shuttle, arginine and proline metabolism, urea cycle, aspartate, beta-alanine, glutamate metabolism, ammonia recycling and citric acid cycle. In conclusion, creep feeding supplementation improved calf performance and induced metabolic changes at weaning and 360 days of age. Although heifers had similar productive performance and reproductive status, when submitted to TAI, those supplemented with creep feeding had greater P/AI.

Effect of postpartum body condition score change on the pregnancy outcomes of lactating Jersey cows inseminated at first service with sexed Jersey or conventional beef semen after a synchronized estrus versus a synchronized ovulation

Our objective was to compare insemination rate and pregnancies per artificial insemination (P/AI) of lactating Jersey cows inseminated at first service with sexed Jersey or conventional beef semen after submission to a Double-Ovsynch protocol for timed artificial insemination (TAI) versus a protocol to synchronize estrus at similar days in milk (DIM). Secondary objectives were to determine the effect of protocol synchrony and postpartum body condition score (BCS) change on P/AI. Lactating Jersey cows (n = 1,272) were allocated by odd versus even ear tag number, which was randomly allocated within the herd, within parity and semen type for submission to a Double-Ovsynch protocol (DO; n = 707) or a protocol to synchronize estrus (ED; n = 565). All ED cows detected in estrus were inseminated (EDAI; n = 424), with undetected cows receiving TAI after an Ovsynch protocol (EDTAI; n = 141). There was a treatment by parity interaction on insemination rate with 100% of DO cows receiving TAI, but a tendency for fewer primiparous ED cows to be detected in estrus and AI than multiparous cows (69.5% ± 0.04% vs. 77.1% ± 0.02%, respectively). For cows inseminated with sexed Jersey or conventional beef semen, DO cows tended to have and had more P/AI than EDAI cows (sexed, 49.2% ± 0.03% vs. 43.6% ± 0.03%; beef, 64.2% ± 0.04% vs. 56.3% ± 0.05%, respectively) and had more P/AI than EDAI+EDTAI cows (sexed, 49.1% ± 0.03% vs. 40.6% ± 0.03%; beef, 65.5% ± 0.04% vs. 56.2% ± 0.04%, respectively). Overall, 29.1% of DO cows expressed estrus with 5.0% and 24.2% of cows detected in estrus ≥24 h before and at TAI, respectively, and there was no difference in P/AI 61 ± 4 d after AI based on expression of estrus at TAI. The synchronization rate was greater for DO than EDAI cows (92.1% ± 0.01% vs. 79.2% ± 0.02%, respectively); however, synchronized DO cows had more P/AI than synchronized EDAI cows (55.0% ± 0.02% vs. 49.2% ± 0.03%, respectively). There was an interaction between BCS change from 7 to 39 ± 2 DIM and treatment on P/AI 61 ± 4 d after AI with no difference between DO and EDAI cows that lost = 0.25 (49.8% ± 0.04% vs. 51.0% ± 0.05%, respectively) or maintained or gained (55.6% ± 0.04% vs. 50.8% ± 0.05%, respectively) BCS, but within cows that lost ≥0.5 BCS, DO cows had more P/AI than EDAI cows (54.1% ± 0.04% vs. 36.1% ± 0.04%, respectively). In conclusion, submission of lactating Jersey cows to a Double-Ovsynch protocol for first insemination increased insemination rate and fertility to first insemination compared with AI after a detected estrus regardless of semen type and expression of estrus, particularly for cows with excessive postpartum BCS loss.

Identification of central regulators related to abdominal fat deposition in chickens based on weighted gene co-expression network analysis

Abdominal fat (AF) is one of the most important economic traits in chickens. Excessive AF in chickens will reduce feed utilization efficiency and negatively affect reproductive performance and disease resistance. However, the regulatory network of AF deposition needs to be further elucidated. In the present study, 300 one-day-old female Wannan chickens were reared to 17 wk of age, and 200 Wannan hens were selected to determine the abdominal fat percentage (AFP). Twenty AF tissue samples with the lowest AFP were selected as the low abdominal fat group (L-AFG), and 20 AF tissue samples with the highest AFP were selected as the high abdominal fat group (H-AFG). Eleven samples from L-AFG and 14 samples from H-AFG were selected for RNA-seq and used for weighted gene co-expression network analysis (WGCNA). Among the 25 RNA-seq samples, 5 samples with the lowest and highest AFP values were selected for differential expression gene analysis. Compared with the L-AFG, 225 and 101 genes were upregulated and downregulated in the H-AFG, respectively. A total of 20,503 genes were used to construct the WGCNA, and 44 co-expression gene modules were identified. Among these modules, 3 modules including turquoise, darkorange2, and floralwhite were identified as significantly associated with AFP traits. Furthermore, several genes including acyl-CoA oxidase 1 (ACOX1), stearoyl-CoA desaturase (SCD), aldehyde dehydrogenase 6 family member A1 (ALDH6A1), jun proto-oncogene, AP-1 transcription factor subunit (JUN), and fos proto-oncogene, AP-1 transcription factor subunit (FOS) involved in the "PPAR signaling pathway," "fatty acid metabolism," and "MAPK signaling pathway" were identified as central regulators that contribute to AF deposition. These results provide valuable information for further understanding of the gene expression and regulation of AF traits and contribute to future molecular breeding for AF in chickens.

Understanding the underlying genetic mechanisms for age at first calving, inter-calving period and scrotal circumference in Bonsmara cattle

BACKGROUND

Reproduction is a key feature of the sustainability of a species and thus represents an important component in livestock genetic improvement programs. Most reproductive traits are lowly heritable. In order to gain a better understanding of the underlying genetic basis of these traits, a genome-wide association was conducted for age at first calving (AFC), first inter-calving period (ICP) and scrotal circumference (SC) within the South African Bonsmara breed. Phenotypes and genotypes (120,692 single nucleotide polymorphisms (SNPs) post editing) were available on 7,128 South African Bonsmara cattle; the association analyses were undertaken using linear mixed models.

RESULTS

Genomic restricted maximum likelihood analysis of the 7,128 SA Bonsmara cattle yielded genomic heritability's of 0.183 (SE = 0.021) for AFC, 0.207 (SE = 0.022) for ICP and 0.209 (SE = 0.019) for SC. A total of 16, 23 and 51 suggestive (P ≤ 4 × 10-6) SNPs were associated with AFC, ICP and SC, while 11, 11 and 44 significant (P ≤ 4 × 10-7) SNPs were associated with AFC, ICP and SC respectively. A total of 11 quantitative trait loci (QTL) and 11 candidate genes were co-located with these associated SNPs for AFC, with 10 QTL harbouring 11 candidate genes for ICP and 41 QTL containing 40 candidate genes for SC. The QTL identified were close to genes previously associated with carcass, fertility, growth and milk-related traits. The biological pathways influenced by these genes include carbohydrate catabolic processes, cellular development, iron homeostasis, lipid metabolism and storage, immune response, ovarian follicle development and the regulation of DNA transcription and RNA translation.

CONCLUSIONS

This was the first attempt to study the underlying polymorphisms associated with reproduction in South African beef cattle. Genes previously reported in cattle breeds for numerous traits bar AFC, ICP or SC were detected in this study. Over 20 different genes have not been previously reported in beef cattle populations and may have been associated due to the unique genetic composite background of the SA Bonsmara breed.

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.

Tenets in Microbial Endocrinology: A New Vista in Teleost Reproduction

Climate vulnerability and induced changes in physico-chemical properties of aquatic environment can bring impairment in metabolism, physiology and reproduction in teleost. Variation in environmental stimuli mainly acts on reproduction by interfering with steroidogenesis, gametogenesis and embryogenesis. The control on reproductive function in captivity is essential for the sustainability of aquaculture production. There are more than 3,000 teleost species across the globe having commercial importance; however, adequate quality and quantity of seed production have been the biggest bottleneck. Probiotics are widely used in aquaculture as a growth promoter, stress tolerance, pathogen inhibition, nutrient digestibility and metabolism, reproductive performance and gamete quality. As the gut microbiota exerts various effects on the intestinal milieu which influences distant organs and pathways, therefore it is considered to be a full-fledged endocrine organ. Researches on Gut-Brain-Gonad axis (GBG axis) and its importance on physiology and reproduction have already been highlighted for higher mammals; however, the study on fish physiology and reproduction is limited. While looking into the paucity of information, we have attempted to review the present status of microbiome and its interaction between the brain and gut. This review will address a process of the microbiome physiological mechanism involved in fish reproduction. The gut microbiota influences the BPG axis through a wide variety of compounds, including neuropeptides, neurotransmitter homologs and transmitters. Currently, research is being conducted to determine the precise process by which gut microbial composition influences brain function in fish. The gut-brain bidirectional interaction can influence brain biochemistry such as GABA, serotonin and tryptophan metabolites which play significant roles in CNS regulation. This review summarizes the fact, how microbes from gut, skin and other parts of the body influence fish reproduction through the Gut-Brain-Gonad axis.

MOET Efficiency in a Spanish Herd of Japanese Black Heifers and Analysis of Environmental and Metabolic Determinants

Multiple ovulation and embryo transfer (MOET) systems have been intensively implemented in Japanese Black cattle in Japan and to create Japanese Black herds out of these areas. Environmental conditions influence MOET efficiency. Thus, we describe results of 137 in vivo, non-surgical embryo flushings performed between 2016-2020, in a full-blood Japanese Black herd kept in Spain and the possible effects of heat, year, bull, donor genetic value, and metabolic condition. Additionally, 687 embryo transfers were studied for conception rate (CR) and recipient related factors. A total of 71.3% of viable embryos (724/1015) were obtained (5.3 ± 4.34/flushing). Donor metabolites did not affect embryo production (p > 0.1), although metabolite differences were observed over the years, and by flushing order, probably related to the donor age. CR was not affected by embryo type (fresh vs. frozen), recipient breed, and whether suckling or not suckling (p > 0.1). CR decreased significantly with heat (44.3 vs. 49.2%; (p = 0.042)) and numerically increased with recipient parity and ET-number. Pregnant recipients showed significantly higher levels of cholesterol-related metabolites, glucose, and urea (p < 0.05). Therefore, adequate MOET efficiency can be achieved under these conditions, and heat stress should be strongly avoided during Japanese Black embryo transfers. Moreover, recipients' metabolites are important to achieve pregnancy, being probably related to better nutrient availability during pregnancy.

Evidence-based hormonal, mutational, and endocrine-disrupting chemical-induced zebrafish as an alternative model to study PCOS condition similar to mammalian PCOS model

Polycystic ovarian syndrome (PCOS) causes swollen ovaries in women at reproductive age due to hormonal disorder with small cysts on the outer edges. The cause of the disorder is still yet to be found. Multiple factors have increased PCOS prevalence, hyperandrogenism, oxidative stress, inflammation, and insulin resistance. Various animal PCOS models have been developed to imitate the pathophysiology of PCOS in humans. Zebrafish is one of the most versatile animal experimental models because of the transparency of the embryos, small size, and rapid growth. The zebrafish similarity to higher vertebrates made it a useful non-mammalian model for PCOS drug testing and screening. This review provides an insight into the usage of zebrafish, a non-mammalian model for PCOS, as an opportunity for evaluating future initiatives in such a research domain.

Investigation of Body Development in Growing Holstein Heifers With Special Emphasis on Body Fat Development Using Bioelectrical Impedance Analysis

This study analyzed skeletal development, body condition, and total body fat development of growing heifers. A total of 144 female primiparous Holstein cattle from four commercial dairy farms with different degrees of stillbirth rates were examined during the rearing period. This included measurements in body condition, fat tissue, metabolic, and endocrine factors. Pelvic measurements and the sacrum height were analyzed to assess skeletal development. The body condition was classified via body condition scoring, bioelectrical impedance analysis (BIA), back fat thickness measurements, and the body mass. For the first time, BIA was used as an appropriate method to evaluate the fat tissue content of cattle throughout the rearing period. This analysis technique can be performed on heifers aged 8–15 months. Throughout that period, the fat content decreased while the skeletal development increased. In addition, high free fatty acid concentrations in serum of the animals with high frame development were found, supporting our hypothesis that stored energy of body fat deposits is used for skeletal growth. Furthermore, we were able to demonstrate complex endocrine relationships between fat metabolism and skeletal growth by using specific markers, such as leptin, insulin growth factor-1 (IGF-1), and estradiol (E2). Food analysis showed high crude protein (CP) levels in the total mixed ration above recommendation for daily protein intake of all farms. However, there was a positive correlation between CP and the body frame measurements in our study. In summary, we established a novel regression formula for BIA analysis (“BIA-Heine”) in heifers to evaluate the body composition throughout different ages and physiological stages in the development of heifers. This special formula allows the evaluation of fat tissue without a whole-body analysis and therefore provides an innovative technique for animal welfare support.

Leptin receptor-deficient (knockout) zebrafish: Effects on nutrient acquisition

In mammals, knockout of LEPR results in a hyperphagic, morbid obese, and diabetic phenotype, which supports that leptin plays an important role in the control of appetite and energy metabolism, and that its receptor, LEPR, mediates these effects. To date, little is known about the role(s) of lepr in teleost physiology. We investigated a zebrafish (Danio rerio) homozygous lepr knockout (lepr^-/-) line generated by CRISPR/Cas9 in comparison to its wt counterpart with respect to nutrient acquisition, energy allocation, and metabolism. The metabolic characterization included oxygen consumption rate and morphometric parameters (yolk sac area, standard length, wet weight, and condition factor) as proxies for use and allocation of energy in developing (embryos, larvae, and juveniles) zebrafish and showed no particular differences between the two lines, in agreement with previous studies. One exception was found in oxygen consumption at 72 hpf, when zebrafish switch from embryonic to early larval stages and food-seeking behavior could be observed. In this case, the metabolic rate was significantly lower in lepr^-/- than in wt. Both phenotypes showed similar responses, with respect to metabolic rate, to acute alterations (22 and 34 °C) in water temperature (measured in terms of Q₁₀ and activation energy) compared to the standard (28 °C) rearing conditions. To assess lepr involvement in signaling the processing and handling of incoming nutrients when an exogenous meal is digested and absorbed, we conducted an in vivo analysis in lepr^-/- and wt early (8 days post-fertilization) zebrafish larvae. The larvae were administered a bolus of protein hydrolysate (0%, 1%, 5%, and 15% lactalbumin) directly into the digestive tract lumen, and changes in the mRNA expression profile before and after (1 and 3 h) administration were quantified. The analysis showed transcriptional differences in the expressions of genes involved in the control of appetite and energy metabolism (cart, npy, agrp, and mc4r), sensing (casr, t1r1, t1r3, t1r2-1, t1r2-2, pept1a, and pept1b), and digestion (cck, pyy, try, ct, and amy), with more pronounced effects observed in the orexigenic than in the anorexigenic pathways, suggesting a role of lepr in their regulations. Differences in the mRNA levels of these genes in lepr^-/-vs. wt larvae were also observed. Altogether, our analyses suggest an influence of lepr on physiological processes involved in nutrient acquisition, mainly control of food intake and digestion, during early development, whereas metabolism, energy allocation, and growth seem to be only slightly influenced.

Ante-Natal and Post-Natal Influences on Neonatal Immunity, Growth and Puberty of Calves-A Review

Simple Summary

The objective of this review is to give the reader an overview of interactions between immunity, growth and puberty in calves and highlight how these influence future performances. The risk of morbidity and mortality is high during the first four weeks of age. Adaption to extra-uterine life starts early during embryonic development and is underpinned by optimal maternal nutrition. It is known that colostrum is paramount to neonate nutrition and passive immunity. Good colostrum management allows the calf to develop coping mechanisms to efficiently utilize feed resources for optimal growth. A deeper understanding of these interactions paves the way for developing strategies to improve immune responses to environmental pathogens, optimal growth and timely attainment of puberty in calves. The literature reviewed here shows that there are opportunities to enhance future performance of cattle paying attention to the interaction of nutrition and immunity at early developmental stages. This then guarantees efficient neonate nutrition and profitable cattle production.

Abstract

Calf immunity, growth and puberty are important factors affecting heifer productivity. The first four weeks of age are critical for reducing calf morbidity and mortality. It is well documented that colostrum is paramount to neonatal nutrition and passive immunity, however, adaptation to extra-uterine life starts early during embryonic development. Therefore, successful calf rearing strategies are underpinned by adequate maternal nutrition during gestation, and good colostrum management. A deeper understanding of these interactions paves the way for developing strategies to improve immune responses to environmental pathogens, optimal growth and timely attainment of puberty in calves. The literature reviewed here shows that there are opportunities to enhance the future performance of cattle paying attention to the interaction of nutrition and immunity at each developmental stage. Therefore, the objective of this review is to give the reader an overview of interactions between immunity, growth and puberty in dairy calves and highlight how these influence future performances.

Effect of calfhood nutrition on metabolic hormones, gonadotropins, and estradiol concentrations and on reproductive organ development in beef heifer calves

This study examined the effect of plane of nutrition on the endocrinological regulation of the hypothalamic-pituitary-ovarian (HPO) axis in beef heifer calves during a critical sexual developmental window early in calf hood. Forty Holstein-Friesian × Angus heifers (mean age 19 d, SEM = 0.63) were assigned to a high (HI; ADG 1.2 kg) or moderate (MOD; ADG 0.50 kg) nutritional level from 3 to 21 wk of life. Intake was recorded using an electronic calf feeding system, BW was recorded weekly, and blood samples were collected on the week of age 5, 10, 15, and 20 for metabolite, reproductive, and metabolic hormone determination. At 19 wk of age, on sequential days, an 8-h window bleed was carried out for luteinizing hormone (LH), follicle-stimulating hormone (FSH), and estradiol analysis. To characterize anterior pituitary gland function, an intravenous GnRH challenge was conducted (19 wk of age). Blood was collected via a jugular catheter every 15 min for 135 min for the analysis of LH, FSH, and estradiol. Calves were subsequently euthanized at 21 wk of age; the anterior pituitary, metabolic organs, and reproductive tract were weighed, and ovarian surface follicular numbers and oocytes recovered were recorded. Mean ADG was 1.18 and 0.50 kg for HI and MOD, respectively, resulting in a 76.6-kg difference in BW (P < 0.001). Blood insulin, glucose, and IGF-1 concentrations were greater (P < 0.001) for HI compared with MOD. There was a diet × time interaction for leptin (P < 0.01); concentrations were greater in HI compared with MOD at 20 wk of age with no difference between treatments before this. Dietary treatment did not alter the concentrations of adiponectin or anti-mullerian hormone. There was a diet × time interaction for FSH, whereby MOD had greater concentrations than HI at 10, 15, and 20, but not at 5 wk of age. Over the duration of an 8-h window bleed (19 wk of age), serum concentrations of LH, LH pulse frequency, and LH pulse amplitude were unaffected by treatment, whereas FSH (0.23 vs. 0.43 ng/mL) and estradiol (0.53 vs. 0.38 ng/mL) concentrations were less than and greater, respectively, for HI than MOD (P < 0.05). Likewise, following a GnRH challenge, the area under the curve analysis revealed greater (P < 0.01) estradiol and lesser (P < 0.01) FSH concentrations in calves on the HI relative to MOD diet, whereas concentrations of LH were unaffected (P = 0.26) between treatments. Ovarian surface follicle numbers were greater (P < 0.05) in HI compared with MOD. Total reproductive tract, uterus, and ovarian tissue expressed relative to BW were greater (P < 0.05) for HI compared with MOD. In conclusion, enhanced nutrition in early calfhood advances the ontogeny development of the HPO axis.

Regulation and function of leptin during ovarian follicular development in cows

Although it is well documented that leptin signals the body nutritional status to the brain, mechanisms of leptin regulation at the ovary are not well understood. This study was conducted to determine whether there was leptin and the receptor for leptin (LEPR) in cattle ovarian follicles and to investigate potential actions of leptin on follicular growth in vivo and on regulation of granulosa cell functions in vitro. There was leptin and LEPR in granulosa and theca cells of dominant and subordinate follicles, with greater immunostaining for leptin in granulosa cells of subordinate follicles. There was a lesser relative abundance of leptin receptor gene-related protein (LEPROT) and of the adiponectin receptors 1 (ADIPOR1) and 2 (ADIPOR2) mRNA transcripts in granulosa cells of subordinate than dominant follicles (P < 0.05). Intrafollicular injection of either 100 or 1000 ng/mL leptin did not affect the diameter and the growth of dominant follicles (P> 0.05). Supplementation of in vitro culture medium with different leptin concentations did not affect (P > 0.05) the relative abundance of hydroxy-delta-5-steroid dehydrogenase, 3 beta- and steroid delta-isomerase 1 (HSD3B1), cytochrome P450 family 11 subfamily A member 1 (CYP11A1), signal transducer and activator of transcription 3 (STAT3) and X-linked inhibitor of apoptosis protein (XIAP) mRNA transcripts in granulosa cells. These findings indicate that leptin and LEPR are present in the follicular cells of cattle ovaries, but leptin apparently does not have essential functions in steroidogenesis and growth of dominant follicles.

The LEPR Gene Is Associated with Reproductive Seasonality Traits in Rasa Aragonesa Sheep

The aim of this study was to characterize and identify causative polymorphisms in the leptin receptor (LEPR) gene responsible for the seasonal variation of reproductive traits in sheep. Three reproductive seasonality traits were studied: the total days of anoestrous (TDA), the progesterone cycling months (P4CM) and the oestrous cycling months (OCM). In total, 18 SNPs were detected in 33 ewes with extreme values for TDA and OCM. Six SNPs were non-synonymous substitutions and two of them were predicted in silico as deleterious: rs596133197 and rs403578195. These polymorphisms were then validated in 239 ewes. The SNP rs403578195, located in exon 8 and leading to a change of alanine to glycine (Ala284Gly) in the extracellular domain of the protein, was associated with the OCM trait, being the G allele associated with a decrease of 12 percent of the OCM trait. Haplotype analyses also suggested the involvement of other non-synonymous SNP located in exon 20 (rs405459906). This SNP also produces an amino acid change (Lys1069Glu) in the intracellular domain of the protein and segregates independently of rs403578195. These results confirm for the first time the role of the LEPR gene in sheep reproductive seasonality.

Associations of feed efficiency with circulating IGF-1 and leptin, carcass traits and meat quality of lambs

The aim of this study was to investigate the effects of feed efficiency classifications on live animal measurements, circulating IGF-1 and leptin concentrations, and carcass, non-carcass and meat quality traits of lambs. One-hundred and two lambs approximately 70 days-old with initial live weight of 24.6 ± 3.71 kg (mean ± SD) were individually fed for 56 days to determine residual feed intake (RFI) and residual feed intake and gain (RIG). Lambs were then classified as phenotypically Low-, Medium- or High-RFI and Low-, Medium- or High-RIG phenotypes. Circulating leptin and IGF-1 concentrations were higher in more efficient lambs (Low-RFI or High-RIG). Variation in RFI and RIG did not affect meat redness or tenderness, but High-RIG lambs had darker meat. These findings show that the phenotypically more efficient Low-RFI and High-RIG lambs produced carcasses with similar characteristics and meat quality as the less efficient High-RFI and Low-RIG lambs but have a strategic advantage of lower feed intake to achieve similar production outcomes.

Differing planes of pre- and postweaning phase nutrition in Holstein heifers: II. Effects on circulating leptin, luteinizing hormone, and age at puberty

The objectives were to investigate the effects of differing planes of pre- and postweaning nutrition on prepubertal serum leptin concentrations, LH profiles, and age at puberty in Holstein heifers. Thirty-six Holstein calves were randomly assigned to either a low (5 L) or high (10 L of whole milk/d) preweaning plane of nutrition from 1 to 7 wk of age, a transition diet (a dry total mixed ration with 85% of concentrate) from wk 8 to 10, and to either a low (70%) or high (85% of concentrate dry total mixed ration) postweaning plane from 11 to 25 wk of age. Serum leptin concentrations were measured every 2 wk from 1 to 25 wk of age, and LH profiles were determined both at wk 15 and 25 based on sequential blood samples taken every 12 min over 10 h. Starting at 26 wk of age, ovaries were examined weekly by transrectal ultrasonography until first ovulation (puberty) was confirmed. Heifers that received the high preweaning plane diet had greater mean (± standard error; SE) leptin concentrations during the preweaning phase than those fed the low plane (2.9 ± 0.1 vs. 2.6 ± 0.1 ng/mL). During the postweaning phase, mean circulating leptin was greater in heifers fed the high compared with the low postweaning diet [3.2 ng/mL (95% confidence interval; CI = 2.7 to 3.4) vs. 2.5 ng/mL (95% CI = 2.3 to 2.8)]. Mean (± SE) amplitude (2.1 ± 0.1 vs. 1.7 ± 0.1 ng/mL), peak (2.2 ± 0.1 vs. 1.8 ± 0.1 ng/mL), and duration (35.6 ± 2.1 vs. 28.7 ± 2.0 min) of LH pulses assessed at wk 15 were greater in heifers offered the high than those offered the low preweaning plane, but no nutritional effects were observed on LH pulses at wk 25. Mean (± SE) age at puberty was 250 ± 9 d and was not influenced by planes of nutrition. However, the likelihood of attaining puberty by 30 wk of age was greater (hazard ratio = 3.8; 95% CI = 1.0 to 14.4) in heifers fed the high postweaning plane compared with the low plane. Heifers achieving puberty by 30 wk also had greater leptin concentrations from wk 1 to 25, whereas for every 1 ng/mL increase in circulating leptin at wk 15 and 25, days to puberty were estimated to decrease by 22 d (95% CI = 1 to 44) and 13 d (95% CI = 1 to 24), respectively. Increasing the preweaning plane from 5 to 10 L/d of whole milk increased serum leptin concentrations at wk 1, 3, and 5 and LH pulse amplitude, peak, and duration at wk 15. Increasing the postweaning plane from 70 to 85% of concentrate resulted in greater circulating leptin concentrations, which may be linked to an earlier onset of puberty.

Weighted single-step genome-wide association study and pathway analyses for feed efficiency traits in Nellore cattle

The aim was to conduct a weighted single-step genome-wide association study to detect genomic regions and putative candidate genes related to residual feed intake, dry matter intake, feed efficiency (FE), feed conversion ratio, residual body weight gain, residual intake and weight gain in Nellore cattle. Several protein-coding genes were identified within the genomic regions that explain more than 0.5% of the additive genetic variance for these traits. These genes were associated with insulin, leptin, glucose, protein and lipid metabolisms; energy balance; heat and oxidative stress; bile secretion; satiety; feed behaviour; salivation; digestion; and nutrient absorption. Enrichment analysis revealed functional pathways (p-value < .05) such as neuropeptide signalling (GO:0007218), negative regulation of canonical Wingless/Int-1 (Wnt) signalling (GO:0090090), bitter taste receptor activity (GO:0033038), neuropeptide hormone activity (GO:0005184), bile secretion (bta04976), taste transduction (bta0742) and glucagon signalling pathway (bta04922). The identification of these genes, pathways and their respective functions should contribute to a better understanding of the genetic and physiological mechanisms regulating Nellore FE-related traits.

Timing is everything: Drivers of interannual variability in blue whale migration

Blue whales need to time their migration from their breeding grounds to their feeding grounds to avoid missing peak prey abundances, but the cues they use for this are unknown. We examine migration timing (inferred from the local onset and cessation of blue whale calls recorded on seafloor-mounted hydrophones), environmental conditions (e.g., sea surface temperature anomalies and chlorophyll a), and prey (spring krill biomass from annual net tow surveys) during a 10 year period (2008-2017) in waters of the Southern California Region where blue whales feed in the summer. Colder sea surface temperature anomalies the previous season were correlated with greater krill biomass the following year, and earlier arrival by blue whales. Our results demonstrate a plastic response of blue whales to interannual variability and the importance of krill as a driving force behind migration timing. A decadal-scale increase in temperature due to climate change has led to blue whales extending their overall time in Southern California. By the end of our 10-year study, whales were arriving at the feeding grounds more than one month earlier, while their departure date did not change. Conservation strategies will need to account for increased anthropogenic threats resulting from longer times at the feeding grounds.

High Salt Diet Affects the Reproductive Health in Animals: An Overview

Simple summary

Halophytic plants are a promising animal feed source. However, the extreme NaCl₂ salt content constraints their use. Excess diet salt adversely affects growth performance and animal’s reproduction worldwide. This review focuses on the impact of high salt intake on growth performance and reproduction ability in animals.

Abstract

Salinity is a reliable issue of crop productivity loss in the world and in certain tropical and subtropical zones. However, tremendous progress in the genetic improvement of plants for salinity tolerance has been made over several decades. In light of this, halophytic plants can be used as animal feeds and have promising features because they are a good feed resource. However, the main constraint of saline pasture systems is the extreme concentration of NaCl salt in drinking water and forage plants for grazing animals. Ecological reports revealed that excess diet salt causes mortality and morbidity worldwide. Animal fed halophytic forages may have adverse effects on growth performance and reproductive function in males and females due to inducing reductions in hormone regulation, such as testosterone, FSH, LH, and leptin. It was indicated that high salt intake promotes circulating inflammatory factors in the placenta and is associated with adversative effects on pregnancy. This review focuses on the scientific evidence related to the effect of high salt intake on growth performance, spermatogenesis, sperm function, and testicular morphology changes in male animals. In addition, the review will also focus on its effect on some female reproductive features (e.g., ovarian follicle developments, placental indices, and granulosa cell function).

Effects of central and peripheral administration of an acute-phase protein, α-1-acid-glycoprotein, on feed intake and rectal temperature in sheep

In rodents, an acute-phase protein, α-1-acid-glycoprotein (AGP), was shown to provide a link between inflammation and suppression of feed intake by acting as a leptin receptor agonist. The objective of this study was to determine the effects of AGP on feed intake and rectal temperature in sheep. Ewes were ovariectomized, implanted with a cannula into a lateral ventricle of the brain, and kept indoors in individual pens. Feed intake and rectal temperature were determined for sheep in all experiments. In the first experiment, ewes (n = 4) received 1 of 4 treatments [0 (control), 0.012 (low), 0.06 (medium), or 0.30 (high) mg/kg BW AGP] into the lateral ventricle (ICV). All sheep received all treatments in a Latin square design balanced for carryover effects with 10 d between treatments. In the second experiment, ewes (n = 10) received 1 of 2 treatments (0 and 3 mg/kg BW of AGP) intravenously (IV) in a completely randomized design. In the third experiment, ewes (n = 19) received peripheral treatments (IV) of an antipyretic [0 (control) or 2.2 mg/kg BW flunixin meglumine (FLU)] 30 min before receiving central AGP [0 (control) or 0.3 mg/kg BW of AGP] in a completely randomized design. All data were analyzed using a mixed model analysis of variance and tested for effects of treatment, time, and the interaction of treatment and time. Cumulative 48-h feed intake after administration of treatments was also determined. In the first experiment, there was no effect of ICV treatment (P = 0.37) on feed intake rate or on cumulative feed intake (P = 0.31). There was an effect of ICV treatment (P = 0.002) on rectal temperatures, which were greater (P < 0.05) after the high dose of centrally administered AGP. In the second experiment, there was no effect of AGP administration IV on feed intake rate (P = 0.98), on cumulative feed intake (P = 0.41) or on rectal temperature (P = 0.71). In the third experiment, there was an effect of central AGP treatment (P < 0.0001) and an interaction of central AGP and time (P < 0.0001) on rectal temperature, whereas FLU had no effect (P = 0.93), demonstrating that AGP increased rectal temperatures regardless of antipyretic treatment. These results indicate that central AGP increases rectal temperature in sheep by pathways that do not involve prostaglandins. Further research is needed to determine whether AGP may be an important integrator of energy balance and inflammation.

Weaning Holstein Calves at 17 Weeks of Age Enables Smooth Transition from Liquid to Solid Feed

Development of calves depends on prenatal and postnatal conditions. Primiparous cows were still maturing during pregnancy, which can lead to negative intrauterine conditions and affect the calf's metabolism. It is hypothesized that weaning calves at higher maturity has positive effects due to reduced metabolic stress. We aimed to evaluate effects of mothers' parity and calves' weaning age on growth performance and blood metabolites. Fifty-nine female Holstein calves (38.8 ± 5.3 kg birth weight, about 8 days old) were used in a 2 × 2 factorial experiment with factors weaning age (7 vs. 17 weeks) and parity of mother (primiparous vs. multiparous cows). Calves were randomly assigned one of these four groups. Live weight, live weight gain and morphometry increased over time and were greater in calves weaned later. Metabolic indicators except total protein were interactively affected by time and weaning age. Leptin remained low in early-weaned calves born to primiparous cows, while it increased in the other groups. The results suggest that weaning more mature calves has a positive effect on body growth, and calves born to primiparous cows particularly benefit from this weaning regimen. It also enables a smooth transition from liquid to solid feed, which might reduce the associated stress of weaning.

Ultrasonographic measures of body fatness and their relationship with plasma levels and adipose tissue expression of four adipokines in Welsh pony mares

Obesity is responsible for metabolic dysregulations that alter fertility and induce pathologies. The objectives of the present study were to validate a reliable method for the evaluation of body fatness in mares and to associate the body fat estimation data to metabolic changes, including adipokines at the plasma and adipose tissue levels. To reach this purpose, animals were subjected to two extreme breeding conditions to study the variation of morphological, ultrasound, and physiological parameters. Twenty Welsh mares were followed up monthly from April to October before and after animals were moved outdoors to grasslands. Body weight (BW), body length (BL), height at the withers (HW), thoracic perimeter (TP), 5-point body condition score (BCS), and subcutaneous fat thickness (SFT) at the level of the shoulder, the lumbar region, and the rump, measured by ultrasonography, and plasma and adipose tissue metabolic indicators were assessed in parallel. Statistical analysis was performed using a linear mixed-effects model, whereas Pearson tests were used for the analysis of the correlations between the different parameters. Although mean BW did not increase significantly (P = 0.0940), TP (P = 0.0002) and BCS (P < 0.0001) increased during the study period. Ultrasonographic examination of subcutaneous adipose tissue showed an increase in SFT at the level of the shoulder (P < 0.0001), lumbar region (P < 0.0001), and rump (P < 0.0001). Plasma concentrations of nonesterified fatty acids (P < 0.0001), phospholipids (P < 0.0001), and cholesterol (P < 0.0001) increased significantly, whereas triglycerides (P < 0.0001) decreased significantly during the study period. Although both plasma concentrations and adipose tissue expression of leptin (P < 0.0001) and resistin (P < 0.0001) increased significantly, adiponectin (P < 0.0001) significantly decreased and visfatin remained unchanged (P = 0.8401). Expression of adipokine receptors studied showed the opposite pattern compared with their ligand. Ultrasonographic measurements of subcutaneous adipose tissue thickness at the shoulder, lumbar region, and rump are relevant indicators of fatness related with adipokine plasma concentrations and expression of adipokine-related receptors in adipose tissue, and particularly highlight seasonal effects.

Effects of leptin on the follicular development and mitochondrial activity of ovine isolated early antral follicles cultured in vitro

This study evaluated the effect of leptin on the in vitro culture of isolated sheep early antral follicles. Early antral follicles (300-450 μm) were isolated and cultured for 12 days in tissue culture medium 199 (TCM 199) supplemented with glutamine, hypoxanthine, transferrin, insulin, selenium, ascorbic acid, bovine serum albumin (BSA) and recombinant follicle stimulating hormone (rFSH) (TCM 199⁺: control medium) or TCM 199⁺ supplemented with 2 or 10 ng/mL leptin. After culture, oocytes were subjected to in vitro maturation (IVM). The parameters analyzed were morphology, extrusion rate, follicular diameter, growth and fully-grown oocytes (oocytes ≥110 μm) rates. After IVM, reactive oxygen species (ROS) levels, mitochondrial activity, meiotic stages and meiotic resumption rates were also analyzed. After 12 days of culture, the concentration of 2 ng/mL of leptin showed a higher percentage of morphologically normal follicles, fully-grown oocytes (≥110 μm), active mitochondria and meiotic resumption compared to the control medium (TCM 199⁺; P < 0.05) but did not differ when compared to leptin concentration of 10 ng/mL (P > 0.05). After culturing, no significant differences existed among treatments in terms of the follicle diameter and ROS levels. In conclusion, the addition of 2 ng/mL leptin to the base culture medium is capable of improving follicular survival, oocyte growth, mitochondrial activity and meiotic resumption after the in vitro culture of isolated sheep early antral follicles.

Fluctuating reproductive rates in Hawaii's humpback whales, Megaptera novaeangliae, reflect recent climate anomalies in the North Pacific

Alongside changing ocean temperatures and ocean chemistry, anthropogenic climate change is now impacting the fundamental processes that support marine systems. However, where natural climate aberrations mask or amplify the impacts of anthropogenic climate change, identifying key detrimental changes is challenging. In these situations, long-term, systematic field studies allow the consequences of anthropogenically driven climate change to be distinguished from the expected fluctuations in natural resources. In this study, we describe fluctuations in encounter rates for humpback whales, Megaptera novaeangliae, between 2008 and 2018. Encounter rates were assessed during transect surveys of the Au'Au Channel, Maui, Hawaii. Initially, rates increased, tracking projected growth rates for this population segment. Rates reached a peak in 2013, then declined through 2018. Specifically, between 2013 and 2018, mother-calf encounter rates dropped by 76.5%, suggesting a rapid reduction in the reproductive rate of the newly designated Hawaii Distinct Population Segment of humpback whales during this time. As this decline coincided with changes in the Pacific decadal oscillation, the development of the NE Pacific marine heat wave and the evolution of the 2016 El Niño, this may be another example of the impact of this potent trifecta of climatic events within the North Pacific.

The vital roles of boron in animal health and production: A comprehensive review

Boron (B) has many beneficial functions in biological, metabolic and physiological processes for plants and animals. It plays a vital role in maintaining animal health and preventing nutritional disorders. Boron deficiency has been correlated with low immune function and high incidence of osteoporosis which increases mortality risk. Extraordinary boron level causes cell damage and toxicity in human and different animal species. In the past few years, attention has been paid to clear the pleiotropic effects of boron including activating of immune response, antioxidant detoxification activities, affecting bone metabolism, enhancing animal performance and modulating various body systems. Furthermore, the role of boron as anti-heat stress agent has been identified in plants and suggested in animals. Liver metabolism also shows significant alterations in dairy cows in response to the dietary supplementation of boron. Likewise, adding boron to animal feed enhances bone density, wound healing and embryonic development. Additionally, boron has a potential impact on the metabolism of numerous minerals and enzymes. In view of the information about boron benefits, high or low level boron merits the concern. As well, researches are required to do more in-depth investigations on boron influences, and to adjust its requirements in different animal species.

The expression and distribution of a leptin receptor in the central nervous system, digestive organs, and gonads of the giant freshwater prawn, Macrobrachium rosenbergii

In the present study, the presence and distribution of leptin receptor (LEP-R) in central nervous system, digestive organs, gonads of giant freshwater prawn, Macrobrachium rosenbergii, were investigated with Western blot and immunohistochemistry. By Western blot a LEP-R with a molecular weight (MW) of 100 kDa was detected in the brain, thoracic ganglia, abdominal ganglia, hepatopancreas, all parts of the gastrointestinal tract, ovaries, and testes. In hepatopancreas and foregut, another intense positive band was detected at molecular weight of 30 kDa, which could be an isotype of LEP-R. By immunohistochemistry, LEP-R-ir was detected in the neurons, and neuropils in the brain, thoracic ganglia, and abdominal ganglia. In the gastrointestinal tract, there was intense LEP-R-ir in the apical part of the epithelial cells of the foregut, midgut, and hindgut. In addition, LEP-R-ir was found in the Restzellen(R)cells and Fibrillenzellen(F) cells in the hepatopancreas. In the ovary, LEP-R-ir was detected in early stage of oocytes and mature oocytes. Intense LEP-R-ir was observed in spermatogonia and spermatocytes of the small and orange claw male prawns. In addition, LEP-R was seen in the high epithelium of spermatic ducts from all male morphotypes. In summary, the detection of the LEP-R-ir suggests the existence of a LEP-R in several organs of M. rosenbergii. Through binding with leptin peptide, LEP-R may be an important signaling molecule that has critical functions in modulating and controlling food intake, energy expenditure, and reproduction in this prawn.

Association of serum leptin levels and pulmonary tuberculosis: a meta-analysis

Background

We performed a meta-analysis to investigate the association of serum leptin levels with the pathogenesis of pulmonary tuberculosis (PTB).

Methods

The retrieval of related articles was achieved through searching the electronic databases according to strict inclusion criteria. The STATA version 12.0 statistical software was employed to calculate the standardized mean difference (SMD) and 95% confidence interval (CI) during the statistical analysis.

Results

Twelve case-control studies were enrolled in this meta-analysis. Our finding showed that serum leptin levels of healthy controls were markedly higher than those of PTB patients (SMD =0.70, 95% CI =0.51-0.89, P<0.001). Stratified analysis based on ethnicity presented that lower serum leptin levels were apparently associated with the development of PTB among both Asians and Caucasians (Asians: SMD =0.38, 95% CI =0.15-0.61, P=0.001; Caucasians: SMD =1.54, 95% CI =1.17-1.91, P<0.001). Furthermore, subgroups analysis based on the detecting method also showed that there was an association between the serum leptin levels and the development of PTB in both ELISA subgroup and RIA subgroup (ELISA: SMD =1.03, 95% CI =0.81-1.26, P<0.001; RIA: SMD =-0.41, 95% CI =-0.82 to -0.01, P=0.045).

Conclusions

In conclusion, our present findings suggest that decreased serum leptin levels may be associated with the pathogenesis of PTB.

Peri-conception and first trimester diet modifies reproductive development in bulls

Nutritional perturbation during gestation alters male reproductive development in rodents and sheep. In cattle both the developmental trajectory of the feto–placental unit and its response to dietary perturbations is dissimilar to that of these species. This study examined the effects of dietary protein perturbation during the peri-conception and first trimester periods upon reproductive development in bulls. Nulliparous heifers (n = 360) were individually fed a high- or low-protein diet (HPeri and LPeri) from 60 days before conception. From 24 until 98 days post conception, half of each treatment group changed to the alternative post-conception high- or low-protein diet (HPost and LPost) yielding four treatment groups in a 2 × 2 factorial design. A subset of male fetuses (n = 25) was excised at 98 days post conception and fetal testis development was assessed. Reproductive development of singleton male progeny (n = 40) was assessed until slaughter at 598 days of age, when adult testicular cytology was evaluated. Low peri-conception diet delayed reproductive development: sperm quality was lowered during pubertal development with a concomitant delay in reaching puberty. These effects were subsequent to lower FSH concentrations at 330 and 438 days of age. In the fetus, the low peri-conception diet increased the proportion of seminiferous tubules and decreased blood vessel area in the testis, whereas low first trimester diet increased blood vessel number in the adult testis. We conclude that maternal dietary protein perturbation during conception and early gestation may alter male testis development and delay puberty in bulls.

Interaction of dietary energy source and body weight gain during the juvenile period on metabolic endocrine status and age at puberty in beef heifers

Using a previously established model for nutritional acceleration of puberty, beef heifers ( = 48; 1/2 Angus × 1/4 Hereford × 1/4 Brahman) were used in a replicated 2 × 2 factorial design to examine the effects of diet type (high forage [HF] vs. high concentrate [HC]) and rate of BW gain (low gain [LG], 0.45 kg/d, vs. high gain [HG], 0.91 kg/d) on key metabolic hormones and age at puberty. After weaning at 14 ± 1 wk of age, heifers were assigned randomly to be fed HC-HG, HC-LG, HF-HG, or HF-LG ( = 12/group) beginning at 4 mo of age for 14 wk. Heifers were then switched to a common growth diet until puberty. Average daily gain was greater ( < 0.04) during the dietary treatment phase in HG heifers (0.81 ± 0.06 kg/d) than in LG heifers (0.43 ± 0.06 kg/d), and there was no diet type × rate of gain interaction. Puberty was achieved at a younger age (54.5 ± 1.8 wk) in both HG groups than in LG groups (60.2 ± 1.9 wk; < 0.04), but dietary energy source (HC vs. HF) did not influence this variable. Moreover, mean BW at puberty did not differ by diet type or rate of gain during the dietary treatment phase. Nonetheless, heifers fed HC-HG exhibited a striking increase ( < 0.0001) in serum leptin beginning at 26 ± 1 wk of age and remained elevated ( < 0.01) throughout the remainder of the experimental feeding phase compared to all other treatments. However, serum leptin in HC-HG dropped precipitously when heifers were switched to the common growth diet and did not differ from that of other groups thereafter. Overall mean concentrations of serum glucose were greater ( < 0.006) in HG heifers than in LG during the dietary treatment phase, with serum insulin also greater ( < 0.04) in HG than in LG only during weeks 20, 22, and 30. Mean serum IGF-1 was not affected by dietary type or rate of BW gain. We speculate that failure of the marked increase in serum leptin observed in HC-HG heifers during the dietary treatment phase to further accelerate puberty compared to HF-HG occurred because of its abrupt decline at the onset of the common growth phase, thus attenuating the temporal cue for activation of the reproductive neuroendocrine system.

Mitotic index and morphological characteristics of ovarian small follicles from goats submitted to nutritionally unbalanced regimens

The objective of this study was to assess the influence of nutritional regimens such as adequate feeding, restricted feeding, and underfeeding–refeeding on the follicle growth and development from caprine ovaries. Goats were divided into three different groups (n = 5 per group). For 24 weeks, goats received elephant grass plus concentrate to provide 1.5 (n = 5) and 0.72 (n = 10) times the energy requirements for maintenance of live weight. Underfed goats were subsequently refed for 6 weeks with the diet of the nourished group (1.5 times the energetic requirements of maintenance). Follicular morphology and morphometry, as well as granulosa cells mitotic index were assessed. Ovarian follicles were classified as small or large preantral follicles, or as small or large antral follicles. Ovarian volume was smaller in animals from both underfed and refed groups than in those animals from fed group. Although no difference in the total number of normal follicles was observed among the nutritional groups, underfed animals presented higher percentages of atretic preantral and small antral follicles when compared with fed animals. Large antral follicles from underfed and refed goats presented a lower mitotic index when compared with fed ones. In conclusion, ovaries from goats challenged with prolonged undernutrition will be functionally compromised, which is characterized by atresia of preantral and small antral follicles and decreased mitotic index of large antral follicles. Refeeding those animals will not recover ovarian function to a same level experienced by goats fed a diet with adequate energy requirements.

Involvement of plasma adipokines in metabolic and reproductive parameters in Holstein dairy cows fed with diets with differing energy levels

This study aimed to investigate the association between plasma adipokine concentrations and metabolic and reproductive parameters in Holstein dairy cows fed diets with different energy levels during the peripartum period. The experiment started 1 mo before first calving and was maintained for 2 lactations. Dry matter intake and energy balance in animals fed a low-energy (LE) diet were significantly lower than that of animals fed a high-energy (HE) diet in the first lactation. Body weight, milk production, back fat thickness, and plasma concentrations of fatty acids, glucose, and insulin were not affected by diet, whereas plasma leptin and adiponectin concentrations were lower and plasma resistin concentrations higher in animals fed the LE diet. Unlike concentrations of adiponectin, plasma resistin concentrations were positively correlated with back fat thickness and plasma fatty acids concentrations and negatively correlated with dry matter intake and plasma leptin concentrations. No effect of diet was found on reproductive variables; that is, pregnancy rates at 35 or 90 d after artificial insemination (AI); numbers of small (3-5 mm), medium (>5 and ≤7 mm), and large (>7 mm) follicles; calving-to-AI and calving-to-calving intervals; and magnitude and duration of the LH surge. However, the commencement of luteal activity after first calving occurred sooner and the frequency of LH pulses was higher in the HE group than in the LE group. A significant positive correlation was found between the number of follicles (of any size) and the area under the curve of plasma resistin concentrations. The number of small follicles was also positively correlated with the nadir of plasma resistin concentrations. Taken together, these results suggest that dietary energy content in the range applied here can alter the resumption of ovarian activity and LH pulsatility without affecting fat mobilization. Plasma adipokine profiles (leptin, resistin, and adiponectin) were significantly altered by diet and negative energy balance but relationships with reproductive variables were limited to follicular growth characteristics and plasma resistin concentrations.

Food Intake Affects Sperm-Egg Fusion Through the GIP/PSG17 Axis in Mice

In addition to overeating, starvation also reduces fecundity in mammals. However, little is known about the molecular mechanisms linking food intake to fertility, especially in males. Gastric inhibitory polypeptide (GIP), which is released from intestinal K-cells after meal ingestion, stimulates insulin secretion from pancreatic β-cells through the action of incretin and has several extrapancreatic effects. Here, we identified GIP receptor (Gipr) expression in mouse spermatids. Microarray analysis revealed that pregnancy-specific glycoprotein 17 (Psg17), a potential CD9-binding partner, was significantly decreased in GIP receptor-knockout (Gipr-/-) testes. Glycosylphosphatidylinositol-anchored PSG17 was expressed on the surface of acrosome-reacted sperm, and Gipr-/- sperm led to a lower fertilization rate in vitro, compared with that of Gipr+/+ sperm, both in the absence and presence of the zona pellucida. Plasma GIP concentrations and Psg17 messenger RNA (mRNA) were immediately increased in the testis after a single meal, whereas ingestion of a chronic high-fat diet markedly decreased Gipr and Psg17 mRNA. These results suggest that reduced GIP signaling, by decreased GIP levels or the downregulation of Gipr, is associated with the reduction of fecundity due to starvation or overeating. Thus, proper regulation of GIP signaling in the testis could be a potential unique therapeutic target for male infertility in obese and diabetic individuals.

Leptin-like immunoreactivity in the central nervous system, digestive organs, and gonads of the giant freshwater prawn, Macrobrachium rosenbergii

Leptin, a highly conserved adipocyte-derived hormone, plays important roles in a variety of physiological processes, including the control of fat storage and metabolic status which are linked to food intake, energy homeostasis, and reproduction in all vertebrates. In the present study, we hypothesize that leptin is also present in various organs of the fresh water prawns, Macrobrachium rosenbergii. The existence and distribution of a leptin-like peptide in prawn tissues were verified by using Western blotting (WB) and immunohistochemical detection (ID) using primary antibody against human leptin. With WB, a leptin-like peptide, having a molecular weight of 15kDa, was detected in the brain, thoracic ganglia, abdominal ganglia, parts of the gastro-intestinal tract, hepatopancreas, adipocytes and gonads. By ID, leptin immunoreactivity (leptin-ir) was detected in the brain, thoracic ganglia and intersegmental commissural nerve fibers of abdominal ganglia. In the gastrointestinal tract, there was intense leptin-ir in the apical part of the epithelial cells of the cardiac and pyloric parts of the stomach. In the midgut and hindgut, the leptin-ir was detected in epithelial cells and basal cells located near the basal lamina of the epithelium. In addition, there was leptin-ir in the Restzellen cells in the hepatopancreas which produce digestive enzymes. In the ovary, the strong intensity of a leptin-ir was detected in the cytoplasm of middle to late stage oocytes, whereas no positive staining was detected in follicular cells. An intense leptin-ir was detected in spermatocytes and sustentacular cells in the seminiferous tubules in the testes of small and orange claw males. Taken together, the detection of the leptin-ir in several organs implicates the existence of a leptin-like peptide in various organs of the freshwater prawn; and like in vertebrates this peptide may be an important hormonal factor in controlling feeding and reproductive process.

Feeding distillers dried grains in replacement of forage in limit-fed dairy heifer rations: Effects on metabolic profile and onset of puberty

The objective of this study was to determine the effect of increasing the inclusion rate of distillers dried grains (DDGS) in replacement of forage in limit-fed diets on the metabolic profile and onset of puberty in dairy heifers. A 16-wk randomized complete block design study was conducted using 48 Holstein heifers (199 ± 2 d of age) with 3 treatments. Treatments were (1) 30% DDGS (30DG), (2) 40% DDGS (40DG), and (3) 50% DDGS (50DG), with the remainder of the diet consisting of grass hay and 1.5% mineral mix. Heifers were housed in groups of 6 and individually limit-fed using Calan gates at 2.65, 2.50, and 2.35% of body weight (BW) on a dry matter (DM) basis for 30DG, 40DG, and 50DG, respectively. Jugular blood samples were collected during wk 0, 4, 8, 12, and 16 for metabolite and metabolic hormone analysis. Additional samples were taken during wk 16 for plasma fatty acid analysis. When heifers weighed 200 kg, coccygeal vein blood samples were taken twice per week for progesterone analysis to estimate onset of puberty. Blood samples continued until cycling was confirmed via ultrasound for the presence of a corpus luteum. A quadratic response and a linear tendency in the proportion of total fatty acids as linoleic acid were observed. Linear and quadratic responses for plasma concentrations of linoleic acid and arachidonic acid occurred. Overall results for fatty acid analysis demonstrated that total fatty acid and polyunsaturated fatty acids concentration in the blood were linearly increased, with a quadratic response for polyunsaturated fatty acids with 30DG and 50DG having the greatest concentrations. No interactions of treatment by week were observed for any of the metabolites and metabolic hormones measured. Glucose, insulin, insulin-like growth factor-1, leptin, and triglycerides were similar across treatments. A linear response of plasma urea nitrogen and a quadratic response tendency for cholesterol concentration were observed. Age and BW at puberty were similar across treatments. Limit-feeding heifers with greater inclusion rates of DDGS maintained energy status without the accumulation of excess adipose tissue as indicated by leptin. Treatments had no detrimental effects on age or BW at puberty.

Identification of a novel leptin receptor duplicate in Atlantic salmon: Expression analyses in different life stages and in response to feeding status

In recent years rapidly growing research has led to identification of several fish leptin orthologs and numerous duplicated paralogs possibly arisen from the third and fourth round whole genome duplication (3R and 4R WGD) events. In this study we identify in Atlantic salmon a duplicated LepRA gene, named LepRA2, that further extend possible evolutionary scenarios of the leptin and leptin receptor system. The 1121 amino acid sequence of the novel LepRA2 shares 80% sequence identity with the LepRA1 paralog, and contains the protein motifs typical of the functional (long form) leptin receptor in vertebrates. In silico predictions showed similar electrostatic properties of LepRA1 and LepRA2 and high sequence conservation at the leptin interaction surfaces within the CHR/leptin-binding and FNIII domains, suggesting conserved functional specificity between the two duplicates. Analysis of temporal expression profiles during pre-hatching stages indicate that both transcripts are involved in modulating leptin developmental functions, although the LepRA1 paralog may play a major role as the embryo complexity increases. There is ubiquitous distribution of LepRs underlying pleiotropism of leptin in all tissues investigated. LepRA1 and LepRA2 are differentially expressed with LepRA1 more abundant than LepRA2 in most of the tissues investigated, with the only exception of liver. Analysis of constitutive LepRA1 and LepRA2 expression in brain and liver at parr, post-smolt and adult stages reveal striking spatial divergence between the duplicates at all stages investigated. This suggests that, beside increased metabolic requirements, leptin sensitivity in the salmon brain might be linked to important variables such as habitat, ecology and life cycle. Furthermore, leptins and LepRs mRNAs in the brain showed gene-specific variability in response to long term fasting, suggesting that leptin's roles as modulator of nutritional status in Atlantic salmon might be governed by distinct genetic evolutionary processes and distinct functions between the paralogs.

Southern Right Whale (Eubalaena australis) Reproductive Success is Influenced by Krill (Euphausia superba) Density and Climate

The reproductive success of southern right whale (Eubalaena australis) depends on body condition and, therefore, on foraging success. This, in turn, might be affected by climatically driven change in the abundance of the species main prey, krill (Euphausia superba), on the feeding grounds. Annual data on southern right whale number of calves were obtained from aerial surveys carried out between 1997 and 2013 in southern Brazil, where the species concentrate during their breeding season. The number of calves recorded each year varied from 7 to 43 ( = 21.11 ± 11.88). Using cross-correlation analysis we examined the response of the species to climate anomalies and krill densities. Significant correlations were found with krill densities (r = 0.69, p = 0.002, lag 0 years), Oceanic Niño Index (r = -0.65, p = 0.03, lag 6 years), Antarctic Oscillation (r = 0.76, p = 0.01, lag 7 years) and Antarctic sea ice area (r = -0.68, p = 0.002, lag 0 years). Our results suggest that global climate indices influence southern right whale breeding success in southern Brazil by determining variation in food (krill) availability for the species. Therefore, increased frequency of years with reduced krill abundance, due to global warming, is likely to reduce the current rate of recovery of southern right whales from historical overexploitation.

N-carbamylglutamate and L-arginine improved maternal and placental development in underfed ewes

The objectives of this study were to determine how dietary supplementation ofN-carbamylglutamate (NCG) and rumen-protected L-arginine (RP-Arg) in nutrient-restricted pregnant Hu sheep would affect (1) maternal endocrine status; (2) maternal, fetal, and placental antioxidation capability; and (3) placental development. From day 35 to day 110 of gestation, 32 Hu ewes carrying twin fetuses were allocated randomly into four groups: 100% of NRC-recommended nutrient requirements, 50% of NRC recommendations, 50% of NRC recommendations supplemented with 20g/day RP-Arg, and 50% of NRC recommendations supplemented with 5g/day NCG product. The results showed that in maternal and fetal plasma and placentomes, the activities of total antioxidant capacity and superoxide dismutase were increased (P<0.05); however, the activity of glutathione peroxidase and the concentration of maleic dialdehyde were decreased (P<0.05) in both NCG- and RP-Arg-treated underfed ewes. The mRNA expression of vascular endothelial growth factor and Fms-like tyrosine kinase 1 was increased (P<0.05) in 50% NRC ewes than in 100% NRC ewes, and had no effect (P>0.05) in both NCG- and RP-Arg-treated underfed ewes. A supplement of RP-Arg and NCG reduced (P<0.05) the concentrations of progesterone, cortisol, and estradiol-17β; had no effect on T4/T3; and improved (P<0.05) the concentrations of leptin, insulin-like growth factor 1, tri-iodothyronine (T3), and thyroxine (T4) in serum from underfed ewes. These results indicate that dietary supplementation of NCG and RP-Arg in underfed ewes could influence maternal endocrine status, improve the maternal–fetal–placental antioxidation capability, and promote fetal and placental development during early-to-late gestation.