Follicle Growth and Oocyte Developmental Competence in Cows With Liver Damage

Abstract

Follicle growth, oocyte quality or oocyte growing environment (follicular fluid) were evaluated in cows with severe liver damage (haemorrhage, telangiectasis, cholangitis and abscess) that were visually diagnosed at the slaughterhouse. Holstein cows aged 40-90 months with either a healthy liver (HL cow) or damaged liver (DL cow) were selected as donors. Follicle development kinetics was evaluated by counting the follicles at various developmental stages. In addition, the biochemical characteristics of the follicular fluids, developmental competence of preantral follicles cultured for 16 days in vitro and the ability of oocytes to develop to the blastocyst stage 8 days after fertilization were examined. DL cows had fewer secondary follicles than HL cows, and the correlation between the number of secondary follicles and the number of primary follicles differed among DL and HL cows. The follicular fluid of DL cows contained significantly lower levels of albumin and a higher total protein content than that of HL cows. Oocyte nuclear maturation assessed at 5, 16 and 21 h after beginning of culture was slower in DL cows than in HL cows, although the final maturation rates did not differ. The rate of polyspermic fertilization was significantly higher and the proportion of cleavage at 48 h after insemination and blastulation lower in DL cows compared with HL cows. When preantral follicles were cultured in vitro, the rate of follicles with normal morphology was lower in DL cows than in HL cows. These findings suggest that the kinetics of folliculogenesis differ among DL and HL cows and the developmental ability of preantral follicles and oocytes is lower in DL cows than in HL cows.

Liver Condition Affects Bovine Oocyte Qualities by Changing the Characteristics of Follicular Fluid and Plasma

“…In our previous report (Iwata et al. ), FF derived from DL cows had high TP, T‐cho, UN, AST and iP and low Alb, LDH and CPK compared with that derived from HL cows, which agrees with our present results.…”

“…We hypothesized that damaged liver conditions affect the characteristics of plasma and FF in a similar way and that the FF derived from cows having damaged livers (DL‐FF) would induce the abnormal nuclear and low cytoplasmic maturation that was observed in our previous report (Iwata et al. ).…”

“…After 21 h of IVM, COCs were fertilized with frozen–thawed semen from a Japanese black bull as described previously (Iwata et al. ). After fertilization, COCs were washed three times and cultured in 100 μl of IVC medium (10 embryos/drop).…”

“…To the best of our knowledge, there has been only one report studying the relationship between oocyte competence and liver condition (Iwata et al. ). That report showed that the ability of oocytes derived from cows having damaged livers (DL cows) to mature, fertilize and develop to the blastocyst stage was low.…”

The Developmental Potential of Oocytes is Impaired in Cattle with Liver Abnormalities

“…Iwata et al . [43] also found a slowed progression to metaphase II in oocytes of cattle with liver abnormalities. Oocytes are exposed to some detrimental substances in the FF for 7–10 days of follicular growth and maturation in vivo , a period obviously considerably longer than the 24 h for in vitro maturation of oocytes.…”