Immunization against inhibin improves in vivo and in vitro embryo production

Effects of donor age and reproductive history on developmental potential of ovum pickup oocytes in Japanese Black cattle (Wagyu)

The objectives of this study were to analyze the (1) effects of donor age and multiparity on development of in vitro fertilization (IVF) embryos after ovum pickup (OPU), (2) effects of repeated and consecutive OPU-IVF procedures on embryo development, and (3) embryo production from OPU-IVF in donors with differing embryo yields after multiple ovulation and embryo transfer technology (MOET) in Japanese Black cattle (Wagyu). Donors were pre-treated with low-dosage follicle-stimulating hormone (FSH; 200 IU total), and oocytes were collected via OPU and fertilized by IVF to generate blastocysts. The number of oocytes collected per OPU session per donor was lower in heifers (2-4 years old, 5.3 oocytes) than in primiparous and pluriparous cows (2-10 years old, 13.6-19.1 oocytes; P < 0.05). Rates of blastocyst development for oocytes from heifers (33.1%) were lower than for those from cows (2-10 years old, 44.1-54.3%; P < 0.05), and average blastocyst yield/OPU/animal was lower in heifers (3.7) than in 5-6 years old cows (10.1; P < 0.05). Donors undergoing five consecutive OPU-IVF sessions after low-dosage FSH showed similar oocyte retrieval (12.2-15.1 oocytes per OPU/animal), blastocyst development rates (35.6-45.0%), and embryo yield/OPU/animal (4.8-5.8; P > 0.05) across sessions. Additionally, embryo yield from OPU-IVF was significantly improved in animals with previous low embryo yield from MOET (5.9 vs. 2.6, respectively, P < 0.05). These results indicate that Wagyu cows with previous births can be more productive as OPU-IVF donors than heifers, and oocytes from donors undergoing to five consecutive OPU-IVF cycles are competent for embryo development without loss of embryo yield/OPU/animal. Moreover, OPU-IVF can be used for embryo production and breeding from all elite Japanese Black cattle, regardless of previous low embryo yield in routine MOET.

Immunization against inhibin DNA vaccine as an alternative therapeutic for improving follicle development and reproductive performance in beef cattle

The objective of the present study was to investigate the potential role of immunization against INH on follicular development, serum reproductive hormone (FSH, E2, and P4) concentrations, and reproductive performance in beef cattle. A total of 196 non-lactating female beef cattle (4-5 years old) with identical calving records (3 records) were immunized with 0.5, 1.0, 1.5, or 2.0 mg [(T1, n = 58), (T2, n = 46), (T3, n = 42) and (T4, n = 36), respectively] of the pcISI plasmid. The control (C) group (n = 14) was immunized with 1.0 mL 0.9% saline. At 21d after primary immunization, all beef cattle were boosted with half of the primary immunization dose. On day 10 after primary immunization, the beef cattle immunized with INH DNA vaccine evidently induced anti-INH antibody except for the T1 group. The T3 group had the greatest P/N value peak among all the groups. The anti-INH antibody positive rates in T2, T3 and T4 groups were significantly higher than that in C and T1 groups. RIA results indicated that serum FSH concentration in T2 group increased markedly on day 45 after booster immunization; the E2 amount in T3 group was significantly increased on day 10 after primary immunization, and the levels of E2 also improved in T2 and T3 groups after booster immunization; the P4 concentration in T2 group was significantly improved on day 21 after primary immunization. Ultrasonography results revealed that the follicles with different diameter sizes were increased, meanwhile, the diameter and growth speed of ovulatory follicle were significantly increased. Furthermore, the rates of estrous, ovulation, conception, and twinning rate were also significantly enhanced. These findings clearly illustrated that INH DNA vaccine was capable of promoting the follicle development, thereby improving the behavioral of estrous and ovulation, eventually leading to an augment in the conception rates and twinning rate of beef cattle.

Efficacy of Immunization against a Novel Synthetic 13-Amino Acid Betaglycan-Binding Peptide Sequence of Inhibin α Subunit on Promoting Fertility in Female Rats

Inhibins suppress the FSH production in pituitary gonadotrope cells by robustly antagonizing activin signaling by competitively binding to activin type II receptors (ACTR II). The binding of inhibin A to ACTR II requires the presence of its co-receptor, namely, betaglycan. In humans, the critical binding site for betaglycan to inhibin A was identified on the inhibin α subunit. Through conservation analysis, we found that a core 13-amino-acid peptide sequence <VRTTSDGGYSFKY> within the betaglycan-binding epitope on human inhibin α subunit is highly conserved across species. Based on the tandem sequence of such a conserved 13-amino-acid betaglycan-binding epitope (INHα13AA-T), we developed a novel inhibin vaccine and tested its efficacy in promoting female fertility using the female rat as a model. Compared with placebo-immunized controls, INHα13AA-T immunization induced a marked (p < 0.05) antibody generation, enhanced (p < 0.05) ovarian follicle development, and increased ovulation rate and litter sizes. Mechanistically, INHα13AA-T immunization promoted (p < 0.05) pituitary Fshb transcription and increased (p < 0.05) serum FSH and 17β-estradiol concentrations. In summary, active immunization against INHα13AA-T potently increased FSH levels, ovarian follicle development, ovulation rate and litter sizes, thus causing super-fertility in females. Therefore, immunization against INHα13AA is a promising alternative to the conventional approach of multiple ovulation and super-fertility in mammals.

Factors affecting superovulation induction in goats (Capra hericus): An analysis of various approaches

Goats are generally called a "poor man's cow" because they not only provide meat and milk but also other assistance to their owners, including skins for leather production and their waste, which can be used as compost for fertilizer. Multiple ovulation and embryo transfer (MOET) is an important process in embryo biotechnology, as it increases the contribution of superior female goats to breeding operations. The field of assisted reproductive biotechnologies has seen notable progress. However, unlike in cattle, the standard use of superovulation and other reproductive biotechnologies has not been widely implemented for goats. Multiple intrinsic and extrinsic factors can alter the superovulatory response, significantly restricting the practicability of MOET technology. The use of techniques to induce superovulation is a crucial step in embryo transfer (ET), as it accelerates the propagation of animals with superior genetics for desirable traits. Furthermore, the conventional superovulation techniques based on numerous injections are not appropriate for animals and are labor-intensive as well as expensive. Different approaches and alternatives have been applied to obtain the maximum ovarian response, including immunization against inhibin and the day-0 protocol for the synchronization of the first follicular wave. While there are several studies available in the literature on superovulation in cattle, research on simplified superovulation in goats is limited; only a few studies have been conducted on this topic. This review describes the various treatments with gonadotropin that are used for inducing superovulation in various dairy goat breeds worldwide. The outcomes of these treatments, in terms of ovulation rate and recovery of transferrable embryos, are also discussed. Furthermore, this review also covers the recovery of oocytes through repeated superovulation from the same female goat that is used for somatic cell nuclear transfer (SCNT).

Rectifying cow infertility under heat stress by immunization against inhibin and supplementation of progesterone

This study was undertaken for the development of novel techniques that are based on immunoneutralization of inhibin bioactivity to improve Holstein cow fertility. A series of 4 experiments were carried out on 2 farms that were located in subtropical or temperate regions, to test the effects of immunization against inhibin alpha subunit on cow fertility under varying degrees of heat stress conditions. Though immunization against inhibin alone improved conception rate (CR) after TAI moderately in cows under mild heat stress conditions, the treatment plus progesterone supplementation substantially enhanced CR in the range of 25 to 35 percentages from severe heat stress to comfortable weather conditions. There existed an additive effect between immunization against inhibin and progesterone supplementation that maximally enhanced CR. Further, immunization against inhibin increased both FSH and activin A concentrations in blood during both follicular and luteal phases. It also significantly increased blood concentrations of E2 in the follicular phase but decreased P4 concentrations during the early pregnancy. However, interferon-tau concentrations in blood around the time of pregnancy recognition were doubled in the inhibin immunized cows. In conclusion, immunization against inhibin plus P4 treatment enhances ovarian follicle and the subsequent early embryo developments that help to greatly improve the fertility of Holstein dairy cows.

Immunization Against Inhibin Promotes Fertility in Cattle: A Meta-Analysis and Quality Assessment

Superovulation and embryo transfer techniques are important methods in cattle breeding. Combined with traditional superovulation protocols, immunization against inhibin can further improve follicular development and embryo yield. The aim of this study is to determine the efficacy of immunization against inhibin in improving the fertility of cattle through meta-analysis and to provide better clinical veterinary practice guidance. Three English databases (PubMed, EMBASE, Web of Science) were searched for research articles of immunizations against inhibin influence on cattle fertility. Literature screening, data extraction, and meta-analysis were conducted in accordance with Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines. In addition, the Systematic Review Center for Laboratory animal Experimentation (SYRCLE) risk-of-bias (RoB) tool was used to assess the risk of bias of the included animal studies. Potentially relevant studies (317) were identified, and finally 14 eligible studies (all in English) were included. The results of meta-analysis revealed that immunization against inhibin has significant effects on improving the number of ovulations [mean difference (MD) = 0.44, 95% confidence interval (CI) = (0.31, 0.56)], embryos and unfertilized ova [MD = 4.51, 95% CI = (2.28, 6.74)], follicles of the three size categories, the incidence of multiple ovulations [OR = 22.50, 95% CI = (8.13, 62.27)], and the conception rate [OR = 2.36, 95% CI = (1.26, 4.40)]. Moreover, it improved the production of embryos [grades 1 embryos: MD = 3.84, (3.54, 4.15); grade 2 embryos: MD = -0.73, (-0.89, -0.57); grade 3 embryos: MD = -0.50, (-0.75, -0.25); degenerated embryos: MD = 1.16, (-0.51, 2.82); transferable embryos: MD = 2.67, (2.03, 3.31)] and the number of corpora lutea [MD = 1.25, 95% CI = (0.79, 1.71)]. In the above indicators, the differences between the two groups were statistically significant (all p < 0.0001). Additionally, according to the quality evaluation results, the risk of bias in the included studies is relatively high. The quality evaluation of the results of the included studies showed that the risk of bias mainly concentrated in the selective, performance, detection, and reporting of bias aspects.

Effect of active immunization with recombinant-derived goose INH-α, AMH, and PRL fusion protein on broodiness onset and egg production in geese (Anser cygnoides)

This study was conducted to investigate the potential effects of active immunization against recombinant-derived goose inhibin-α (INH-α), anti-Müllerian hormone (AMH), and prolactin (PRL) fusion protein on broodiness onset and egg production in geese. The purified fusion proteins (INH-α, AMH, and PRL) were prepared using a prokaryotic expression system. Female Zhedong geese (10 mo old) were randomly assigned to one of 4 treatments and raised in separate pens. The geese were actively immunized with the recombinant goose INH-α, AMH, or PRL, respectively, and phosphate-buffered saline as control. The results showed the corresponding antibodies were produced when the geese were immune INH-α, AMH-, and PRL-recombinant proteins. The significantly higher luteinizing hormone contents were observed in the INH-α, AMH, and PRL recombinant protein-immunized geese, while the lower AMH hormone content only in PRL-immunized birds. AMH recombinant protein immunized geese had more large yellow follicles of ovary, while the INHα-treated birds with more other follicles compared with control geese. In addition, the geese receiving INH-α recombinant protein, the broodiness onset was about 6 d, which significantly shorter than did PBS immunization (16 d). The INHα- and PRL-immunization also resulted in 12.5 and 8.5 d shorter broody duration intervals compared to the control birds. Moreover, the lower new broodiness rate was observed in three recombinant proteins treated birds. Finally, the PRL recombinant protein-immunization resulted in an average increase of 1.34 eggs during a 40-d observation. Collectively, the data demonstrated that active immunization against recombinant proteins INH-α or AMH could promote LH hormone secretion, regulate follicle development and decrease the broodiness rate. Also, active immunization with a recombinant-derived goose PRL protein might improve egg laying performance.

Conception Rate and Reproductive Hormone Secretion in Holstein Cows Immunized against Inhibin and Subjected to the Ovsynch Protocol

Simple Summary

In recent decades, conception rates in lactating dairy cows have dramatically decreased, and improving the conception rate has become a major challenge in dairy cow reproduction. Various Ovsynch protocols have been developed to aid in the resumption of ovarian follicular activity for timely breeding in post-partum cows. However, the effect of Ovsynch protocols on improving the conception rate is unsatisfactory. In addition, immunization against inhibin was reported to improve the fertility of domestic animals. Thus, a novel reproductive technique combining immunization against inhibin and the widely used Ovsynch protocol was proposed and tested in this study. Our results showed that immunization against inhibin has the potential to improve conception rates in cows, but also compromised luteal function. According to these results, additional luteal-stimulating treatments are suggested to further improve cow fertility based on immunization and the Ovsynch protocol.

Abstract

This study was conducted to investigate the feasibility of improving fertility in dairy cows via immunization against inhibin. Thirty-two cows were divided into Control (n = 11), Low-dose (n = 10) and High-dose (n = 11) groups. The High-dose and Low-dose cows were treated with 1 and 0.5 mg of the inhibin immunogen, respectively. All the cows were subjected to the Ovsynch protocol from the day of antigen administration and were artificially inseminated. Blood samples were serially collected over a 24-day period from the start of the Ovsynch protocol to 14 days after insemination. The results showed that immunization against inhibin dose-dependently increased the plasma concentrations of follicle-stimulating hormone (FSH), estradiol (E2), and activin A, but decreased progesterone (P4) concentrations in the luteal phase. Immunization also increased the plasma interferon (IFN)-τ concentrations in pregnant cows on day 14 after initial insemination. The conception rates in High-dose (45.5%) and Low-dose (40%) cows marginally increased compared to that in Control cows (27.3%), but the increases were not significant (p > 0.05). In conclusion, a single immunization against inhibin has the potential to improve conception rates, despite impaired luteal development. To further improve the reproductive performance of dairy cows, additional luteal-stimulating treatments are suggested in combination with immunization against inhibin and Ovsynch techniques.

Simple Recommendations for Improving Efficiency in Generating Genome-Edited Mice

The generation of transgenic model organisms (primarily mice) is an integral part of modern fundamental and applied research. Simple techniques based on the biology of these laboratory rodents can often increase efficiency when generating genome-edited mouse strains. In this study, we share our three years of experience in the optimization of mouse genome editing based on microinjection of CRISPR/Cas9 components into ca. 10,000 zygotes. We tested a number of techniques meant to improve efficiency in generating knockout mice, such as optimization of the superovulation method and choosing the optimal mouse strains to be used as zygote donors and foster mothers. The presented results might be useful to laboratories aiming to quickly and efficiently create new mouse strains with tailored genome editing.

Trends in recombinant protein use in animal production

Recombinant technologies have made possible the production of a broad catalogue of proteins of interest, including those used for animal production. The most widely studied proteins for the animal sector are those with an important role in reproduction, feed efficiency, and health. Nowadays, mammalian cells and fungi are the preferred choice for recombinant production of hormones for reproductive purposes and fibrolytic enzymes to enhance animal performance, respectively. However, the development of low-cost products is a priority, particularly in livestock. The study of cell factories such as yeast and bacteria has notably increased in the last decades to make the new developed reproductive hormones and fibrolytic enzymes a real alternative to the marketed ones. Important efforts have also been invested to developing new recombinant strategies for prevention and therapy, including passive immunization and modulation of the immune system. This offers the possibility to reduce the use of antibiotics by controlling physiological processes and improve the efficacy of preventing infections. Thus, nowadays different recombinant fibrolytic enzymes, hormones, and therapeutic molecules with optimized properties have been successfully produced through cost-effective processes using microbial cell factories. However, despite the important achievements for reducing protein production expenses, alternative strategies to further reduce these costs are still required. In this context, it is necessary to make a giant leap towards the use of novel strategies, such as nanotechnology, that combined with recombinant technology would make recombinant molecules affordable for animal industry.

BMP15 regulates the inhibin/activin system independently of ovulation rate control in sheep

Polymorphisms in the gene encoding bone morphogenetic protein 15 (BMP15) have been associated with multiple ovulations in sheep. As BMP15 regulates inhibin expression in rodents, we assumed that the ovarian inhibin/activin system could mediate part of the effect of BMP15 mutations in the regulation of ovulation rate in sheep. To answer this question, we have studied the effects of two natural loss-of-function mutations of BMP15 on the expression of components of this system. The FecX^R and the FecX^Gr mutations, when present respectively in Rasa Aragonesa ewes at the heterozygous state and in Grivette ewes at the homozygous state, were associated with a twofold increase in ovulation rate. There were only small differences between mutant and wild-type ewes for mRNA expression of INHA, INHBA, ACVR1B, ACVR2A, FST or TGFBR3 in granulosa cells and inhibin A or activin A concentrations in follicular fluid. Moreover, the effects of mutations differed between breeds. In cultures of granulosa cells from wild-type ewes, BMP15, acting alone or in synergy with GDF9, stimulated INHA, INHBA and FST expression, but inhibited the expression of TGFBR3 Activin A did not affect INHBA expression, but inhibited the expression of ACVR2A also. The complexity of the inhibin/activin system, including positive and antagonistic elements, and the differential regulation of these elements by BMP15 and activin can explain that the effects of BMP15 mutations differ when present in different genetic backgrounds. In conclusion, the ovarian inhibin/activin system is unlikely to participate in the increase of ovulation rate associated with BMP15 mutations in sheep.

Immunotherapy using inhibin antiserum enhanced the efficacy of equine chorionic gonadotropin on superovulation in major inbred and outbred mice strains

Improvement of the superovulation technique will help to enhance the efficiency of embryo and animal production. Blocking inhibin using inhibin antiserum (IAS) is known to promote follicular development by increasing the level of FSH. Previously, we reported that coadministration of IAS and eCG produced more than 100 oocytes from a single female C57BL/6 mouse at 4 weeks old. The oocytes derived from the IAS + eCG (IASe) treatment were able to fertilize and develop normally into offspring. In this study, we examined the effect of IASe treatment on the numbers of ovulated oocytes in major inbred (A/J, BALB/cByJ, C3HeJ, DBA/2J, and FVB/NJ) and outbred (CD1) mice strains at 4 weeks old. We confirmed the fertilization and developmental ability of the IASe-derived oocytes. IASe treatment ovulated 1.5 to 3.2 times higher numbers of oocytes than eCG treatment alone. The fertilization rate of IASe-derived oocytes was similar to that of eCG-derived oocytes. In vitro and in vivo developmental rates of the embryos derived from IASe were similar to the rates of embryos derived from eCG. We have shown that superovulation by IASe is very effective in obtaining high numbers of ovulated oocytes from small numbers of oocyte donor in a number of mice strains. The superovulation technique will contribute to the archiving of cryopreserved embryos of genetically engineered mice using small numbers of donors and has the potential to produce more live animals for rederivation of the archived mouse lines in mouse repositories.