Use of new recombinant proteins for ovarian stimulation in ruminants

Baruselli, Pietro Sampaio; Abreu, Laís Ângelo de; Catussi, Bruna Lima Chechin; Oliveira, Ana Carolina dos Santos; Rebeis, Lígia Mattos; Gricio, Emanuele Almeida; Albertini, Sofía; Sales, José Nélio Sousa; Rodrigues, Carlos Alberto

doi:10.1590/1984-3143-ar2023-0092

Cited by 4 publications

(3 citation statements)

References 97 publications

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“…By these mechanisms, eCG treatment induces functional and morphological changes in TA B L E 1 Effect of the dose of eCG (0, 200, and 300 IU) at P4 device removal (D8) on follicular response in Nelore (Bos indicus) heifers submitted to FTAI protocol. the CL, such as the increase in volume and elevation of plasmatic progesterone concentrations (Baruselli et al, 2023).…”

Section: Discussionmentioning

confidence: 99%

“…Moreover, eCG enhanced the density and volume of both small and large luteal cells and mitochondrial density (Rigoglio et al., 2013) and increased the vascular density of the CL (Moura et al., 2015). By these mechanisms, eCG treatment induces functional and morphological changes in the CL, such as the increase in volume and elevation of plasmatic progesterone concentrations (Baruselli et al., 2023).…”

Section: Discussionmentioning

confidence: 99%

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The effectiveness of low‐dose of eCG in timed AI Nelore (Bos indicus) heifers

Neto,

Souza,

Campos

et al. 2024

Reprod Domestic Animals

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This study evaluated the efficacy of the administration of different doses of equine chorionic gonadotropin (eCG; 0 IU, 200 IU, or 300 IU) at the time of the progesterone device removal in 2‐year‐old Nelore (Bos indicus) heifers synchronized for fixed‐timed artificial insemination (FTAI). On day 0 (D0), a total of 398 heifers received 2 mg of oestradiol benzoate i.m., 0.53 mg of cloprostenol i.m., and an eight‐day previously used (second use) intravaginal device containing 1 g of progesterone (P4). Eight days later (D8), simultaneous with the P4 device removal, 0.5 mg of oestradiol cypionate i.m. and 0.53 mg of cloprostenol i.m. were administered. At the same time, heifers were randomly assigned to receive one of the following treatments: G‐0 IU (n = 141; no eCG treatment), G‐200 IU (n = 132; treated with 200 IU of eCG), and G‐300 IU (n = 125; treated with 300 IU of eCG). FTAI was performed 48 h after the P4 device removal (D10). Ultrasonographic evaluations were performed at D0, D10, and D17. Heifers were scanned to measure the size of the largest follicle (LF), the presence, number, and size of the corpus luteum (CL), and the ovulation rate. Subsequently, at D40, the heifers underwent scanning to determine the pregnancy rate and identify any twin pregnancies. Additionally, at D70, scans were performed to assess pregnancy loss (PG). Data were analysed by orthogonal contrasts [C1 (eCG effect): control x (200 IU + 300 IU) and C2 (eCG dose effect): 200 IU × 300 IU]. On D0, CL presence was similar between the groups [G‐0 IU = 65.2% (92/141), G‐200 IU = 55.3% (73/132), and G‐300 IU = 63.2% (79/125); p = .16]. No interactions between the presence of CL on D0 and eCG treatment were found for any of the variables (p > .05). The diameter of the LF at FTAI (D10) was not influenced by eCG treatment (p = .22) or eCG dose (p = .18). However, treatment with eCG increased the diameter of the CL at D17 (G‐0 IU = 15.7 ± 0.3 mmb, G‐200 IU = 16.6 ± 0.2 mma, and G‐300 IU = 16.6 ± 0.3 mma; p = .001), regardless of the dose used (p = .94). The ovulation rate was higher in heifers treated with eCG [G‐0 IU = 79.4%b (112/141), G‐200 IU = 90.2%a (119/132), and G‐300 IU = 93.6%a (117/125); p = .002], but there was no effect of eCG dose (p = .36). Pregnancy per AI (P/AI) on D40 [G‐0 IU = 32.6%b (46/141), G‐200 IU = 42.4%a (56/132), and G‐300 IU = 42.4%a (53/125); P = 0.05] and D70 [G‐0 IU = 29.1%b (41/141), G‐200 IU = 40.9%a (54/132), and G‐300 IU = 40.8%a (51/125); p = .02] were higher on heifers that received eCG; however, no dose effect was observed for P/AI on D40 (p = .89) nor D70 (p = .98). Pregnancy loss between D40 and D70 tended to reduce (p = .07) in eCG‐treated heifers without dose effect (p = .91). Heifers with CL at D0 presented a greater follicle diameter (LF) on D10 (With CL = 11.2 ± 0.2 mm and Without CL = 10.2 ± 0.2 mm; p = .05), CL diameter on D17 (With CL = 15.8 ± 0.03 mm and Without CL = 11.8 ± 0.6 mm; p = .01), and ovulation rate [With CL = 95.5% (233/244) and Without CL = 74.7% (115/154); p = .01]. However, no difference in pregnancy rate at D40 (p = .52) and D70 (p = .84) was found. In conclusion, eCG treatment increases ovulation and pregnancy rates of heifers submitted to a FTAI protocol. Furthermore, eCG treatment increases the diameter of the CL after FTAI and reduces pregnancy losses. No dose effect was observed, suggesting Nelore (Bos indicus) heifers respond to 200 IU of eCG treatment for FTAI.

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Section: Discussionmentioning

confidence: 99%

Section: Discussionmentioning

confidence: 99%

The effectiveness of low‐dose of eCG in timed AI Nelore (Bos indicus) heifers

Neto,

Souza,

Campos

et al. 2024

Reprod Domestic Animals

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“…In the veterinary field, the availability of a rFSH offering consistent physiological results at affordable costs is of utmost relevance for proper livestock reproductive management (Baruselli et al., 2023; Gutiérrez‐Reinoso et al., 2022; Sanderson & Martinez, 2020). Here, we addressed this need by expressing and characterizing a single chain β‐CTP‐α chimera of bovine FSH (scbFSH) in L. tarentolae .…”

Section: Introductionmentioning

confidence: 99%

Expression and functional characterization of chimeric recombinant bovine follicle‐stimulating hormone produced in Leishmania tarentolae

Abreu,

Grunberg,

Bonilla

et al. 2024

Microbial Biotechnology

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Assisted reproductive techniques are routinely used in livestock species to increase and enhance productivity. Ovarian hyperstimulation is a process that currently relies on administering pituitary‐derived follicle‐stimulating hormone (FSH) or equine chorionic gonadotropin in combination with other hormones to promote the maturation of multiple follicles and thereby achieve superovulation. The use of partially purified preparations of FSH extracted from natural sources is associated with suboptimal and variable results. Recombinant FSH (rFSH) has been produced in a variety of heterologous organisms. However, attaining a bioactive rFSH of high quality and at low cost for use in livestock remains challenging. Here we report the production and characterization of a single chain bovine rFSH consisting of the β‐ and α‐subunit fused by a polypeptide linker (scbFSH) using Leishmania tarentolae as heterologous expression system. This unicellular eukaryote is non‐pathogenic to mammals, can be grown in bioreactors using simple and inexpensive semisynthetic media at 26°C and does not require CO2 or bovine serum supplementation. Stable cell lines expressing scbFSH in an inducible fashion were generated and characterized for their productivity. Different culture conditions and purification procedures were evaluated, and the recombinant product was biochemically and biologically characterized, including bioassays in an animal model. The results demonstrate that L. tarentolae is a suitable host for producing a homogeneous, glycosylated and biologically active form of scbFSH with a reasonable yield.

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