Circulating oxidative stress status in Bedouin she-camels (Camelus dromedarius) during the peripartum period

This study aimed to assess the oxidative stress status in blood plasma of nomadic she-camels (Camelus dromedarius) during transition from late pregnancy to early lactation. From 12 late pregnant she-camels, blood was sampled weekly as they progressed from the third week prepartum up to the third week postpartum. Levels of albumin, uric acid, and malondialdehyde (a biomarker of lipid peroxidation) concentrations were fairly constant (P > 0.05) throughout the sampling times. Compared to the initial time (third week prepartum), values of the superoxide anion, total peroxides, and protein carbonyl (a biomarker of protein peroxidation) increased (P < 0.05) by more than 67%, 43%, and 23%, respectively, at parturition and this increase extended to the first week postpartum. Ascorbic acid concentration lost more than 20% (P < 0.05) of its value at parturition. Bilirubin value increased as camels progressed from the first week pre- up to the first week postpartum, and reached its maximum value (~ 2.5 fold) at parturition. Superoxide dismutase activity increased (P < 0.05) by 71.7% at the first week pretpartum and by 57% at parturition. Total antioxidant capacity level increased (P < 0.05) by ~ 25% at the first week prepartum and remained at this high level up to the second week postpartum. It seems that periparturient camels experience a substantial oxidative stress particularly at parturition and the week after calving as indicated by the increased peroxidative by-products of proteins in parallel to the enhanced production of pro-oxidants.

Vitamin C nutrition in cattle

Domestic animals, including ruminants, can synthesize vitamin C (VC) in their liver; as such, the dietary requirement for VC has not been confirmed in these animals. The adequacy of VC has been evaluated by quantifying VC levels in plasma, but the reported values in bovine plasma have been widely variable. Plasma VC concentration is decreased by heat stress, hepatic lesions, fattening, and infectious diseases such as mastitis in cattle. Therefore, VC supplementation is potentially beneficial for cattle with low plasma VC concentration. This review discusses the methods for determination of plasma VC concentration in cattle, VC nutrition, and the efficacy of VC supplementation in calves, dairy cattle, and beef cattle. Additionally I propose a reference range for plasma VC concentration in Japanese Black cattle.

Follicle growth and oocyte developmental competence in cows with liver damage

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.