Provision of beta-glucan prebiotics (cellooligosaccharides and kraft pulp) to calves from pre- to post-weaning period on pasture.

We conducted two feeding experiments to evaluate the effects of supplementation with either cellooligosaccharide or kraft pulp on growth performance in grazing beef calves (Japanese Black) from 4 weeks pre-weaning to 12 to 16 weeks post-weaning. In Experiment 1 (20-week duration), nine calves (2.9-month-old females) were assigned to either a control group (CON) or an experimental group (CEL) fed cellooligosaccharide at a rate of 10 g/day mixed with concentrate. Average daily weight gain tended to be greater in CEL than in CON, especially after 1 month of weaning. In Experiment 2 (16-week duration), 10 calves (2.0-month-old females) were assigned to either a control group or an experimental group (KRA) fed kraft pulp at a rate of 10% replacement of total digestible nutrients with concentrate. The proportion of fibrolytic bacteria increased and that of methanogenic Archaea decreased in the rumen microbial community composition of KRA calves in Experiment 2, whereas the decrease in Fibrobacter and Archaea was observed in CEL calves at first 4 weeks in Experiment 1. We conclude that beta-glucan prebiotic supplementation to grazing calves at pre-weaning would affect rumen microbial composition and modified rumen fermentation characteristics, leading to a better rumen environment via different means.

Effects of cyclophosphamide administration on the in vitro fertilization of mice.

PURPOSE: To evaluate the oocyte fertilization ability and embryo growth after cyclophosphamide (CPA) treatment in mice. METHODS: Mice were treated with CPA at different doses (0-800 mg/kg body weight). The oocytes then were retrieved and evaluated for their in vitro fertilization efficiency. RESULTS: The average number of metaphase II (MII) oocytes significantly decreased by ≥400 mg/kg CPA administration. The fertilization rate also decreased in the group that was treated with ≥400 mg/kg CPA. However, after fertilization, the embryos demonstrated normal growth ability. Two weeks after CPA administration, the number of mice from which the oocytes could be retrieved markedly decreased, but the fertilization rate and development of morphological features in the embryos were similar to those of the controls. One month after CPA administration, the number of mice from which the oocytes could be retrieved, fertilization rate, and development of the morphological features in the embryos were similar to those of the controls. CONCLUSION: The number of oocytes decreased as the CPA administration level increased; however, the oocytes' potential for fertilization and development to the blastocyst stage was not significantly affected. One month after CPA administration, the number of oocytes and the potential for development into blastocysts were recovered.

Prediction of the in vitro developmental competence of early-cleavage-stage human embryos with time-lapse imaging and oxygen consumption rate measurement.

PURPOSE: To assess an embryo's ability to develop into a good-quality blastocyst during the early-cleavage stage using time-lapse imaging and the oxygen consumption rate. METHODS: In total, 942 zygotes had their oxygen consumption rates measured. In total, 282 zygotes were assessed by using time-lapse imaging. In total, 121 zygotes were examined by using both their oxygen consumption rate and time-lapse imaging. RESULTS: The embryos with moderate respiration rates of between 0.41 and 0.61 (×1014/mol s-1) on day 3 had a 22.1% chance of becoming good-quality blastocysts; those outside that range had a 14.3% chance. With the time-lapse system, when the first division was within 24 hours, 22.3% of the embryos grew to good blastocysts. After 24 hours, the rate dropped to 8.6%. The intervals between two consecutive cleavages were calculated and the duration of the second cell cycle was defined. When the time was between nine hours and 13 hours, there was a higher rate of good blastocysts. Regarding both criteria, when the embryos had progressed in the optimal range, a high percentage of them had become good blastocysts; it was 8.0% outside of that range. CONCLUSION: Individual embryos with the potential to develop into good-quality blastocysts could be selected at day 3 of culture using these systems.

Microarray analysis of Longissimus thoracis muscle gene expressions in vitamin A-restricted Japanese Black steers in middle fattening stage.

Vitamin A (VA) restriction in beef cattle improves meat marbling; however, the underlying molecular mechanisms remain incompletely understood. We performed microarray analysis to clarify the effect of VA restriction on Longissimus thoracis gene expressions in Japanese Black steers. Six Japanese Black steers 13-14 months of age were divided into two groups: S group (n = 3), which received VA supplementation, and R group (n = 3), in which dietary VA intake was restricted. Steers were fattened for 7 months, following which tissue samples were obtained. Extracted RNA samples were analyzed by Affymetrix Genechip Bovine Genome Array. Lists of genes highly expressed in the R and S groups were obtained. The lists were functionally interpreted using functional annotation software, DAVID. In the R and S groups, 48 and 40 genes were significantly highly expressed, respectively. The gene list of the R group included CD36, LPL, GPAM, DGAT2, and SCD and additional genes annotated 'PPAR signaling pathway,' 'lipid biosynthesis' and 'mitochondrion,' whereas that of the S group included COL1A2, FN1 and DCN and additional genes annotated 'extracellular matrix.' Changes in the expression of these genes are possibly involved in marbling improvement in beef cattle by VA restriction.

Effects of supplementation with cellooligosaccharides on growth performance of weaned calves on pasture.

We conducted two feeding experiments to evaluate the effects of cellooligosaccharide (CE) supplementation on growth performance in grazing beef calves. Calf sex and age and duration of the experimental period differed between the experiments. Experiment 1 (10 weeks) used 5.6-month-old castrated males; Experiment 2 (13 weeks) used 3.9-month-old females. Eight Japanese Black calves were assigned to either a control group (CON) or an experimental group (CE) fed CE at a rate of 10 g/day mixed with concentrate. Calves were stocked in fields in which Kentucky bluegrass was dominant. In both experiments, average daily gain tended to be greater in CE than in CON, especially in late stages of experiments, but no significant differences in body weight changes were observed. In Experiment 2, final heart girth was larger in CE than in CON calves. We monitored rumen microbial community composition in Experiment 2 and found increases in fibrolytic bacteria and methanogenic archaea in CE calves, but the overall microbial composition did not differ between the groups. Our results suggest that supplementation with CE may positively affect growth performance in weaned calves on pasture, but longer-term CE supplementation may be required to exhibit the effect.