Effect of Short-term Fasting on Hepatic Steroid Hormone Metabolism in Cows

Abstract

ABSTRACT. In the present study, the effect of 4-day fasting on steroid hormone metabolism in the liver and secretion of LH was examined in cows. Six non pregnant, dry Holstein cows were used. The estrous cycle was synchronized in all cows using CIDR-Ovsynch. Cows were allocated to a control group (n=3) and a fasting group (n=3). In the fasting group, cows were fasted for four days from day -4 to day -1 (day 0=day of 2nd GnRH injection) but otherwise were fed ad libitum. The experiment was repeated in a crossover design after an interval of about one month. The peripheral progesterone (P 4 ) concentration in the fasting group was significantly higher than in the control group on day -1 and 0. The peripheral estradiol-17 concentration in the fasting group was also significantly higher than in the control group on day -1 and 0. The portal vein P 4 concentration in the fasting group was significantly higher than in the control group. On day 0, there was no difference in LH secretion between groups. The mean percentages of lipid droplets in liver cells in the fasting group were significantly higher than in the control group on day 0. These results suggest that short-term fasting leads to reduced hepatic steroid hormone metabolism by accumulation of fat in the liver, which causes high peripheral steroid hormone concentrations. Gonadal steroid hormones, such as progesterone (P 4 ) and estradiol-17 (E 2 ), are metabolized primarily in the liver and partially in the kidney and intestine before being excreted into the urine and feces [4]. Peripheral concentrations of these hormones are therefore largely affected by their metabolic clearance rates in the liver, which increase with liver blood flow. In fact, the amount of P 4 flowing into the liver has been directly associated with the plasma P 4 level [12]. Feed intake is another factor that affects steroid metabolism because it is directly correlated with the portal blood flow rate in sheep [12]. Lactating cows, which are maintained with high dry matter intake, have increased hepatic blood flow resulting in 2.3 times higher metabolic clearance rates of E 2 and P 4 compared to non lactating cows [16]. This increased metabolism leads to decreased levels of peripheral E 2 and P 4 , which are associated with decreased reproductive efficiency, such as decreased conception rate, increased pregnancy loss, increased multiple ovulation rate and decreased estrous behavior [16]. Thus, feed intake can affect gonadal steroid hormone secretion by alterations in the liver blood flow. Feed intake is also considered to affect LH secretion from the pituitary gland via the feedback action of steroid hormones.Periparturient dairy cows are in a state of negative energy balance, which results in decreased liver function due to fatty liver. Fatty liver, too, is associated with poorer reproductive performance such as decreased conception rate and longer calving intervals [2]. In the present study, the effect of short-term fasting on steroid hormone metabolism in the liver was investigated by c...

Effect of feed restriction on hepatic estradiol metabolism and liver function in cows

“…We previously reported that in dry cows 4-day fasting leads to reduced hepatic steroid hormone metabolism through accumulation of fat in the liver, which causes high peripheral steroid hormone concentrations [10]. In contrast, in the current study, plasma P 4 concentration was consistently lower in the restricted feeding group.…”

“…Plasma P 4 concentrations were determined by enzyme immunoassay after diethylether extraction as described by Ono et al [10]. The sensitivity of the assay was 0.16 ng/ml, and the intra-and inter-assay CVs were 6.0% and 9.5%, respectively.…”

“…The sensitivity of the assay was 0.16 ng/ml, and the intra-and inter-assay CVs were 6.0% and 9.5%, respectively. Plasma E 2 concentrations were determined by a time-resolved fluorescent immunoassay after diethylether extraction as described by Ono et al [10]. The sensitivity of the assay was 0.80 pg/ml, and the intra-and inter-assay CVs were 5.0% and 10.7%, respectively.…”

Development of ovarian diseases in dairy cows with a history of fatty liver, and their prognosis

“…Veenhuizen et al [ 41 ] reported that the FL progresses to a severe grade before the symptoms of ketosis can appear and that the analysis of ketosis incidence in dairy cattle revealed that the UDP-glucuronosyltransferase (UGT) activity value of the liver is reduced in cases with FL. On the other hand, Ono et al [ 23 ] reported that the progesterone and estrogen levels of the animals in estrus immediately after four days of fasting were significantly higher than those in the non-fasting group and that this elevation was attributed to a metabolic delay due to a reduction in liver blood flow. One of the features of the clinical symptoms in cases with moderate and severe FL is a decrease in the appetite [ 40 ], and it has been suggested that the reason for this could be the increase in the steroid hormone levels due to the reduced blood flow in a FL.…”

“…These animals were then examined for the presence of a FL and its severity by liver biopsy, for which the specimens were blindly collected using a puncture device for cattle liver (Fujihira Co., Tokyo, Japan). The puncture was made within a surgical field set at about 25 cm below the top-line between the right 11th and 12th costal bones [ 23 ]. These animals were divided into four groups based on the severity of the FL as follows: no-FL group (n=133) had hepatic fat deposition rates of <10%; mild FL group (n=99) had hepatic fat deposition rates ranging from 10 to <30%; moderate FL group (n=56) had hepatic fat deposition rates ranging from 30 to <60%; and severe FL group (n=78) had hepatic fat deposition rates of >60% [ 6 ].…”