Beneficial Effects of L-Carnitine Supplementation during IVM of Canine Oocytes on Their Nuclear Maturation and Development In Vitro

Abstract

This study aimed to investigate the effect of L-carnitine (LC) supplementation during in vitro maturation (IVM) of canine oocytes on nuclear maturation, fertilization status, and preimplantation development. Cumulus–oocyte complexes (COCs) collected from the ovaries of ovariohysterectomized female dogs were matured in vitro for 72 h in a TCM-199 medium supplemented with (0.1, 0.3, 0.6, 1.0, or 2.0 mg/mL) or without (0.0 mg/mL) LC. Matured oocytes were fertilized in vitro with frozen–thawed spermatozoa, and zygotes were cultured in a SOF medium for 7 days. IVM rates were higher (p ≤ 0.05) in 0.3 and 0.6 mg/mL LC supplemented groups than in the control (0.0 mg/mL LC) and other LC groups. Fertilization (18 h postinsemination (pi)) and cleavage (2–16-cell stage at day 3 pi) rates were higher (p ≤ 0.05) in the 0.6 mg/mL LC group than in the control and 0.1, 1.0, and 2 mg/mL LC supplemented groups. Interestingly, 4.5% of fertilized oocytes developed to morula (day 5 pi) in the 0.6 mg/mL LC group, which was higher (p ≤ 0.05) than those developed in the 0.3 mg/mL group (1.0%). No cleaved embryos developed to morula in other groups. In conclusion, LC supplementation at 0.6 mg/mL during IVM of canine oocytes improved their maturation, fertilization, and preimplantation embryo development rates following IVF and in vitro culture (IVC).

In vitro maturation medium supplementation: utilization of repaglinide, L-carnitine, and mesenchymal stem cell-conditioned medium to improve developmental competence of oocytes derived from endometriosis mouse models

“…In this regard, the obtained results indicated that the treatment of normal and EMS-induced immature oocytes with LC during IVM increased the proportion of oocytes that reached the MII stage and reduced oocyte degeneration rate. These results are consistent with prior canine and porcine studies demonstrating that adding LC to the IVM medium improved nuclear maturation and subsequent embryo development following IVF (35,36). In addition, here, LC improved cleavage and blastocyst rates as well as total blastocyst cell numbers when added to the maturation medium of EMS-induced and EMS-free mice.…”

Biological roles of l‐carnitine in oocyte and early embryo development

“…Oocyte and embryo developmental competence are affected by several factors, such as metabolite composition of culture media, oxygen concentration, time, and temperature (Nagai, 2001). Several studies demonstrated that L-carnitine supplementation to either IVM or in vitro culture (IVC) media had positive effects on early embryo development, and beneficial effects have been reported in cattle , mice (Abdelrazik et al, 2009), pigs (You et al, 2012), camels (Fathi & El-Shahat, 2017), and canines (Moawad et al, 2021).…”

“…In camels, supplementation of maturation or culture media with 0.5 mg/ml L-carnitine tended to promote nuclear maturation and increase the number of morulae and blastocysts (Fathi & El-Shahat, 2017). In canines, Moawad reported that adding 0.6 mg/ml L-carnitine during IVM exerted beneficial effects on nuclear maturation, fertilization, and developmental capacity of preimplantation embryos (Moawad et al, 2021). In pigs, the inclusion of L-carnitine (0.5-0.6 mg/ml) brought a significant increase in the rates of oocyte | 679 maturation, cleavage (Tamás et al, 2011), and blastocyst development (Wu et al, 2011;You et al, 2012).…”

Canine IVM With SOF Medium, Insulin-Transferrin-Selenium, and Low O2 Tension Improves Oocyte Meiotic Competence and Decreases Reactive Oxygen Species Levels

“…Some authors such as No et al (2018) have used coculture with oviduct epithelial cells to improve maturation rates and have achieved 13% of MII using oocytes recovered from bitches at diestrus and 47% of MII with bitches at estrus. Most reports on canine IVM have been focused on the supplementation of the medium with hormones, such as estrogen, progesterone, follicle-stimulating hormone (FSH), luteinizing hormone (LH), human chorionic gonadotropin (HCG), and L -carnitine ( Moawad et al, 2021 ). The medium TCM-199 is the medium of choice for IVM of most domestic species.…”