Mitochondrial activity during pre-maturational culture in in vitro-grown bovine oocytes is related to maturational and developmental competences.

The objective of this study was to investigate the dynamics of mitochondrial activity in in vitro-grown (IVG) bovine oocytes during pre-maturational culture (pre-IVM) and its relationship to their developmental competence upon being subjected to different pre-IVM durations. After 12-day IVG culture, oocytes were cultured for 0, 10 or 20h with 3-isobutyl-1-methylxanthine (IBMX) as pre-IVM. Mitochondrial activity in IVG oocytes after 10h pre-IVM was the highest among all the pre-IVM durations (P<0.05). In addition, cleavage (79.4%) and blastocyst rates (38.9%) of embryos derived from IVG oocytes with 10h pre-IVM were higher than those with 20h pre-IVM (63.0 and 25.8%, respectively; P<0.05) and similar to those of in vivo-grown oocytes (82.7 and 36.7%, respectively). To confirm the developmental ability of IVG oocytes with 10h pre-IVM beyond the blastocyst stage in vivo, embryo transfer was attempted. Transferred embryos developed to the elongated embryonic stage (63.6%, 7/11) in the recipient uterus at Day 16 of oestrus, and a male calf was delivered (50%, 1/2). In conclusion, it was indicated that the mitochondrial activity of bovine IVG oocytes peaked at 10h pre-IVM and was closely correlated with the nuclear maturation and developmental competences of IVG oocytes.

Effects of Vitamin C Supplementation on The Blood Oxidative Stress and Antibody Titre Against Histophilus Somni Vaccination in Calves.

INTRODUCTION: The purpose of this study was to determine the effects of vitamin C supplementation on blood oxidative stress biomarkers and antibody response to vaccination in calves. MATERIAL AND METHODS: Thirty-four clinically healthy 2 week old Japanese Black calves were randomly assigned to two groups. Seventeen calves formed the VC group which received 1,000 mg of vitamin C daily from 2 to 8 weeks of age, and the other 17 calves of the control group did not receive supplementation. All calves received an inactivated Histophilus somni vaccine at 4 and 8 weeks of age. Blood samples were taken at 2, 4, 8 and 12 weeks of age. RESULTS: The concentration of the serum reactive oxygen metabolites (d-ROMs), and the oxidative stress index (OSI), which is calculated from the d-ROMs and biological antioxidant potential, were significantly lower at 8 weeks of age in the VC group than in the control group (P < 0.05). The antibody titres to H. somni in the VC group were significantly higher than those in the control group at 12 weeks of age after the second vaccination (P < 0.05). CONCLUSION: Vitamin C supplementation to calves may reduce oxidative stress and enhance the antibody production after vaccination with H. somni.

Primary pharyngeal alveolar rhabdomyosarcoma in an adolescent Japanese black heifer.

Alveolar rhabdomyosarcoma (ARMS) is a rare mesenchymal tumor with differentiation toward the skeletal muscle. Although several cases of canine ARMS have been reported in veterinary medicine, only one case of abdominal ARMS has been reported in a cow. A 13-month-old, Japanese black heifer was referred for pus-like nasal discharge. On autopsy, an 11 × 7 × 4.5-cm pedunculated mass closed to the left palatine tonsillar sinus that occupied the laryngopharynx. Histopathological and immunohistochemical analyses indicated that the tumor was a typical ARMS. To the best of our knowledge, this has been the first case of primary pharyngeal ARMS in a Japanese black heifer, which is rare among cows. Nonetheless, its characteristics, including site, age and subtype, are identical to those among humans and dogs.

Effect of Beta-Carotene Supplementation on the Peripheral Blood Leukocyte Population in Japanese Black Calves.

The purpose of this study was to determine the effect of beta-carotene supplementation to Japanese Black calves on the peripheral blood leukocyte population. Twenty-two Japanese Black calves were alternately assigned to two groups. Eleven calves received 20 mg/d of beta-carotene orally from 2 to 8 wk of age (BC group), and the other 11 calves did not receive (control group). The serum beta-carotene concentration in the BC group at 4, 8 and 12 wk of age were significantly higher than those in the control group (p<0.05). The numbers of CD4+ cells in the BC group were significantly higher than those in the control group at 4 wk of age (p<0.05). These results confirmed that beta-carotene supplementation to Japanese Black calves affected the peripheral blood leukocyte population.

Effect of combined vaccination for Pasteurella multocida, Mannheimia haemolytica, and Histophilus somni to prevent respiratory diseases in young Japanese Black calves in the field.

To evaluate the preventive effects of combined vaccination for Pasteurella multocida, Mannheimia haemolytica and Histophilus somni on respiratory diseases in Japanese Black calves, 295 calves at one farm were alternately assigned to two groups; 147 calves received the vaccine at 4 and 8 weeks of age (vaccination group), and the other 148 calves did not receive vaccine (control group). The incidences of respiratory diseases were 25.9 and 70.9% in the vaccination and control groups, respectively, and the odds ratio for comparison between the two groups was 0.143 (95% confidence interval: 0.086-0.238). Administration of the multiple vaccine to Japanese black calves might be one of effective factor for prevention of respiratory diseases.

The relationship between antral follicle count in a bovine ovary and developmental competence of in vitro-grown oocytes derived from early antral follicles.

To clarify the relationship between ovarian reserve and the developmental competence of bovine oocytes, oocyte-granulosa complexes (OGCs) collected from early antral follicles (≤ 1 mm) in ovaries with high (≥ 25) and low (<25) antral follicle counts (AFCs) were used. OGCs derived from different AFC groups were cultured for growth followed by maturation, fertilization and blastocyst formation. Viability of OGCs during growth culture was similar between groups; however, OGCs in the high-AFC group had a larger number of granulosa cells than the low-AFC group at 12 days of growth. The proportion of matured oocytes in the high-AFC group was higher than that in the low-AFC group. Mitochondrial activity of oocytes before maturation in the high-AFC group was higher than that in the low-AFC group; however, accumulation of reactive oxygen species was similar between groups. Cleavage rate in the high-AFC group tended to be higher than that in the low-AFC group, although blastocyst development was similar between groups. In conclusion, oocytes derived from ovaries with high AFC have higher maturational ability and fertilizability than those from low AFC. The difference may be caused by high proliferation of granulosa cells from ovaries with high AFC.

Fertilizability of oocytes derived from Holstein cows having different antral follicle counts in ovaries.

In this study, to clarify the relationship between ovarian reserve and oocyte quality, cumulus-oocyte complexes (COCs) were collected repeatedly by ovum pick-up (OPU) from cows with high and low antral follicle counts (AFCs) at short (3-4 days) and long (7 days) intervals, and COC morphologies and oocyte fertilizability were examined. The relationship between AFC and follicular growth after OPU was also investigated. Cows showing AFC of ≥30 in at least one OPU session were grouped into the high-AFC group. At a short interval, follicular sizes and COC morphologies were similar between the different AFC groups. However, the normal fertilization rate was higher in the high-AFC group than in the low one, although total penetration rates were similar. At a long interval, the percentage of COCs with poor morphology in the high-AFC group was higher and the normal fertilization rate was lower than in the low one. In the low-AFC group, normal fertilization rates at short and long intervals were similar, and mean follicular size became larger at a long than at a short interval. However, mean follicular sizes at short- and long-interval OPU were similar in the high-AFC group. In conclusion, it is suggested that oocytes derived from cows with high AFC had higher fertilizability than those from cows with low AFC when OPUs were performed at a short (3-4 days) interval. However, oocyte quality in high-AFC cows was impaired by long-interval (7 days) OPU, possibly due to the degradation of follicles.