Performance of dairy ewes fed diets with a fibrolytic enzyme product included in the concentrate during the suckling period

Seventy-two multiparous ewes from two dairy breeds (Manchega, n = 36 and Lacaune, n = 36) were used in a replicated 2 × 2 factorial design to evaluate the effects of diet supplementation with an exogenous fibrolytic enzyme product on lactation performance and feed intake during the suckling period (weeks 1 to 4) according to breed. Ewes were blocked in groups of nine and fed ad libitum after lambing a diet based on 70% forage and 30% concentrate to which the enzyme was added after pelleting. Experimental concentrates were: control (without enzyme) and enzyme (fibrolytic enzyme complex, included at 0.47% volume to weight of concentrate). Twenty-four dry and open ewes (Manchega, n = 12 and Lacaune, n = 12) were also grouped by breed and used to measure the fill value of the ration used. During the suckling period, milk yield, milk composition, dry matter intake, lamb growth, as well as body weight change and body condition score change were not affected by enzyme supplementation. Breed effect was significant for milk yield, the Manchega ewes yielding less milk with a higher content of milk components than the Lacaune ewes. The opposite was observed for dry matter intake. Enzyme supplementation reduced intake by 9% in the dry ewes, resulting in a greater fill value of the diet. In conclusion, no lactational effects were detected when the fibrolytic enzyme product was added to the concentrate fed to dairy ewes.     

Synchronization of follicular wave emergence in the seasonally anestrous ewe: the effects of estradiol with or without medroxyprogesterone acetate

Fertility is often lower in anestrous compared to cyclic ewes, after conventional estrus synchronization. We hypothesized that synchronization of ovarian follicular waves and ovulation could improve fertility at controlled breeding in anestrous ewes. Estradiol-17beta synchronizes follicular waves in cattle. The objectives of the present experiments were to study the effect of an estradiol injection, with or without a 12-d medroxyprogesterone acetate (MAP) sponge treatment, on synchronization of follicular waves and ovulation in anestrous ewes. Twenty ewes received sesame oil (n=8) or estradiol-17beta (350 microg; n=12). Eleven ewes received MAP sponges for 12d and were treated with oil (n=5) or estradiol-17beta (n=6) 6d before sponge removal. Saline (n=6) or eCG (n=6) was subsequently given to separate groups of ewes at sponge removal in the MAP/estradiol-17beta protocol. Estradiol treatment alone produced a peak in serum FSH concentrations (4.73+/-0.53 vs. 2.36+/-0.39 ng/mL for treatment vs. control; mean+/-S.E.M.) after a short-lived (6 h) suppression. Six of twelve ewes given estradiol missed a follicular wave around the time of estradiol injection. Medroxyprogesterone acetate-treated ewes given estradiol had more prolonged suppression of serum FSH concentrations (6-18 h) and a delay in the induced FSH peak (32.3+/-3.3 vs. 17.5+/-0.5 h). Wave emergence was delayed (5.7+/-0.3 vs. 1.4+/-0.7d from the time of estradiol injection), synchronized, and occurred at a predictable time (5-7 vs. 0-4d) compared to ewes given MAP alone. All ewes given eCG ovulated 3-4d after injection; this predictable time of ovulation may be efficacious for AI and embryo transfer.     

Endocrine and metabolic factors involved in the effect of nutrition on the production of colostrum in female sheep

We investigated the physiological relationship between diet during pregnancy and colostrum production in ewes to test the hypothesis that for ewes that are in low body condition, with low fat reserves, the food supply will be the main source of energy for colostrum synthesis. To this end, we measured the amount of colostrum accumulated by ewes under two levels of nutrition. We also measured the circulating concentrations of metabolites and hormones associated with lactogenesis (beta-hydroxybutyrate, glucose, progesterone, prolactin, cortisol, growth hormone, leptin, insulin and insulin-like growth factor-I) Ewes were either under-fed at 70 (n = 15) or well-fed at 110% (n = 10) of their daily metabolisable energy requirement during the last two months of pregnancy. Colostrum accumulation up to parturition was 168 +/-48 g for under-fed ewes and 451 +/-103 g for well-fed ewes. After birth, under-fed ewes produced less colostrum than well-fed ewes but the difference was no longer significant. The level of nutrition also influenced the plasma concentrations of hormones and metabolites related to lactogenesis. Progesterone concentrations decreased before lambing in all animals but in under-fed ewes the fall appeared to be too small to initiate the onset of colostrum production. Beta-hydroxybutyrate concentrations were higher in under-fed than in well-fed ewes, suggesting that the under-fed ewes were mobilising more adipose tissue but they still did not meet their ME requirements for colostrum production. We concluded that, in underfed ewes, there are insufficient nutrients for adequate lactation and the hormone regime is inappropriate for good udder development and colostrum synthesis.     

Pulsatile LH secretion and ovarian follicular wave emergence and growth in anestrous ewes

The objective of this study was to determine if pulsatile LH secretion was needed for ovarian follicular wave emergence and growth in the anestrous ewe. In Experiment 1, ewes were either large or small (10 × 0.47 or 5 × 0.47 cm, respectively; n = 5/group) sc implants releasing estradiol-17 beta for 10 d (Day 0 = day of implant insertion), to suppress pulsed LH secretion, but not FSH secretion. Five sham-operated control ewes received no implants. In Experiment 2, 12 ewes received large estradiol-releasing implants for 12 d (Day 0 = day of implant insertion); six were given GnRH (200 ng IV) every 4 h for the last 6 d that the implants were in place (to reinitiate pulsed LH secretion) whereas six Control ewes were given saline. Ovarian ultrasonography and blood sampling were done daily; blood samples were also taken every 12 min for 6 h on Days 5 and 9, and on Days 6 and 12 of the treatment period in Experiments 1 and 2, respectively. Treatment with estradiol blocked pulsatile LH secretion (P < 0.001). In Experiment 1, implant treatment halted follicular wave emergence between Days 2 and 10. In Experiment 2, follicular waves were suppressed during treatment with estradiol, but resumed following GnRH treatment. In both experiments, the range of peaks in serum FSH concentrations that preceded and triggered follicular wave emergence was almost the same as control ewes and those given estradiol implants alone or with GnRH; mean concentrations did not differ (P < 0.05). We concluded that some level of pulsatile LH secretion was required for the emergence of follicular waves that were triggered by peaks in serum FSH concentrations in the anestrous ewe.     

Effect of dried corn distillers’ grains with solubles and soybean meal supplements on physiological indicators and reproductive performance of ewes

This study aimed to evaluate the effects of adding dried distillers’ grains with solubles (DDGS) to the nutritional regimens of ewes at different time periods on reproductive traits, serum hormones and serum metabolites. In Experiment 1, 100 ewes were divided into 4 groups (n = 25) according to diet. The four diets were grass hay (H) alone (group H), H with barley (group H + B), H with DDGS for the whole feeding period (27 d) (group H + DDGS) or H and DDGS for 5 d (d 8–12 of oestrus cycle) (group H + DDGS5). Serum progesterone concentrations were affected by oestrus cycle (p < 0.001), but not by dietary treatments. However, feeding H + DDGS caused significant increases in serum insulin, leptin and growth hormone concentrations (p < 0.05). In Experiment 2, 30 ewes were divided into 2 groups (n = 15), receiving DDGS or soybean meal (SBM) during the prepartum period. Diets had no significant effect on weights of dams or lambs at birth; however, the weaning weights of lambs born from ewes of group DDGS were significantly higher (p < 0.05). Moreover, serum glucose, blood urea nitrogen, triglyceride and beta hydroxybutyric acid (BHBA) concentrations during the prepartum period were affected by dietary treatments and by time (p < 0.001). During the prepartum period, BHBA concentrations of ewes fed SBM were higher, while BHBA levels decreased during the last weeks of pregnancy regardless of diet. Lamb serum immunoglobulin G concentrations increased from 1 h to 24 h after birth (p < 0.001). Colostrum of ewes fed SBM had higher fat-free dry matter (DM) and protein contents in comparison to colostrum of ewes fed DDGS (p < 0.05). In conclusion, DDGS can be included as protein source in pregnancy rations up to 15% of DM to obtain reproductive performance outcomes equal to or exceeding those obtained with SBM.     

Fasting ghrelin does not predict food intake after short-term energy restriction

Objective: To study the role of ghrelin as a hunger signal during energy restriction and to test the hypothesis that changes in fasting leptin concentrations during energy restriction are associated with changes in fasting ghrelin concentrations. Research Methods and Procedures: Thirty‐five healthy, lean men (23 ± 3 years of age; BMI: 22.3 ± 1.6 kg/m²) participated in a controlled intervention study. Fasting ghrelin and leptin concentrations were measured before and after 2 days of 62% energy restriction and after a 2‐day period of ad libitum food intake. Energy intake during the latter period was assessed. Results: On average, ghrelin concentrations did not change (0.05 μg/liter; 95% confidence interval, ?0.03; 0.12) during energy restriction. Changes in ghrelin concentration during energy restriction were not associated with energy intake during the ad libitum period (r = 0.07; not significant). Ad libitum energy intake was, however, associated with the change in ghrelin concentrations during the same period (r = ?0.34; p = 0.05). Ghrelin and leptin concentrations were not associated. In addition, the ratio of percentage changes in ghrelin and leptin during energy restriction was not correlated with ad libitum food intake after energy restriction (r = ?0.26; p = 0.14). Discussion: Fasting ghrelin concentrations did not rise after a 2‐day energy restriction regimen. Moreover, changes in ghrelin concentrations during energy restriction were not associated with subsequent ad libitum food intake, suggesting that fasting ghrelin does not act as a hunger signal to the brain. The data did not support our hypothesis that leptin suppresses ghrelin levels.     

Estrogen and progesterone receptor content in the pituitary gland and uterus of progesterone-primed and gonadotropin releasing hormone-treated anestrous ewes

The objective of this work was to investigate the effect of progesterone (P) and gonadotropin-releasing hormone (GnRH) treatment on estrogen receptor (ER) and P receptor (PR) concentrations in the pituitary gland and uterus of anestrous ewes. Ewes were either not treated (group C, n = 4); were treated with 0.33 g P-controlled internal drug release (P-CIDR) for 10 days (group P, n = 4), with GnRH, 6.7 ng i.v. injections every 2 h for 18 h followed by a 4 microg bolus administration of Receptal at 20 h (group GnRH, n = 4), or with a combination of the P and GnRH treatment (group P + GnRH, n = 3). Ewes were humanely killed either at the beginning of the experiment (group C), when the CIDR was removed (group P), or 24 h after the GnRH bolus treatment (groups GnRH and P + GnRH). Progesterone treatment increased serum P concentrations, indicating that the treatment was effective. All GnRH treated ewes had similar luteinizing hormone (LH) surges, which lasted 8 h. At slaughter, estradiol (E2) concentrations in the GnRH group were higher than in groups C, P, and P + GnRH. Treatment with GnRH increased more than 10-fold the content of ER and PR in the pituitary gland without altering steroid receptor concentrations in the uterus. When GnRH was combined with P the uterine receptor contents were higher than with P treatment alone. The treatment with P decreased ER and PR content in the uterus, but had no effect on the pituitary gland. The results show that regulation by P and GnRH of ER and PR content in anestrous ewes is tissue-specific.     

Ghrelin levels increase after pictures showing food

The neuropeptide ghrelin is a major signal for food intake in various species including humans. After exogenous ghrelin administration, food intake and body weight increase in rodents. In normal human subjects, ghrelin administration increases self-rated appetite and calorie intake and prompts the imagination of favorite meals. It is unclear so far whether ghrelin levels are affected by external cues such as sight of food. We investigated the influence of pictures showing food compared to neutral pictures on ghrelin levels in young normal male subjects (n = 8). The study consisted of two consecutive sessions with a one-week interval. During each session, blood for later analysis of plasma concentrations of ghrelin was collected between 08:15 and 13:00 every 15 min (between 10:30 and 11:30 every 10 min). Breakfast and lunch was provided at 08:30 and 12:00, respectively. Fifty pictures were presented from 10:30 to 10:45 showing neutral images during the first session and food contents during the second session. As expected, ghrelin levels increased before each meal independent of the picture contents. In addition, ghrelin levels during the 30-min interval following the presentation of pictures with food increased significantly compared to the 30-min interval before this presentation (area under the curve (AUC): 188 % vs. 158 %, P < 0.05). The difference in the increases between the two picture conditions was also significant (P < 0.05). Our findings suggest that sight of food elevates ghrelin levels in healthy volunteers.     

Effects of late gestation shearing on BW,feed intake and plasma metabolite concentrations in Rambouillet ewes managed outdoors during winter

The majority of lambs in the United States are born from late winter to early spring and pregnant ewes are generally sheared in the last third of pregnancy. Although there are benefits to shearing before parturition, shorn animals may be more vulnerable to the cold, highly variable climatic conditions associated with these seasons. The objective of this study was to determine if late gestation shearing induces differences in individual BW, dry matter intake (DMI) and plasma metabolite concentration of finewool ewes managed outdoors during winter. Thirty-six mature, pregnant Rambouillet ewes (3.8±0.45 years; 76.8±11.4 kg) were managed in a drylot with ad libitum access to pelleted alfalfa in bunks capable of measuring individual daily DMI. The treatment group consisted of ewes sheared at ~5 weeks before the estimated parturition date (shorn; n=18). Unshorn ewes (n=18) remained in full fleece throughout the experiment and were shorn on the last day of the experiment ~2 weeks before the estimated parturition date. Blood was collected on days 0 (before shearing shorn group), 7, 14 and 21 (before shearing unshorn group) of the trial, and plasma was isolated and analyzed for non-esterified fatty acid (NEFA), β-hydroxybutyrate (BHB) and glucose (GLU) concentrations. There was no effect of shearing on ewe DMI or BW during the trial (P⩾0.35). Plasma NEFA and GLU concentrations were similar (P⩾0.36) between shearing groups, though plasma BHB concentration was 103.7 μmol/l greater (24.1%; P<0.01) in unshorn ewes. Lamb BW at birth was not affected (P=0.30) by ewe shearing treatment. Under conditions of this study, no differences in economically important aspects of sheep production were observed between shorn and unshorn pregnant ewes.     

Effect of long-term and short-term progestagen treatment on follicular development and pregnancy rate in cyclic ewes

The aim of this study was to evaluate the effect of the length of a progestagen treatment (12 d vs. 6 d) on follicular dynamics, estrus synchronization and pregnancy rate using medroxyprogesterone acetate (MAP) with or without an eCG dose at the end of MAP treatment. One hundred sixty Polwarth ewes were divided into four equal groups: long-term treated (LT, n=40); short-term treated (ST, n=40); long-term treated plus eCG (LTeCG, n=40); and short-term treated plus eCG (STeCG, n=40). Five ewes of each group were separated to undergo daily transrectal ultrasonography, and blood samples were taken for hormone determination. Until 96 h after sponge withdrawal the number of ewes in estrus was higher in both long-term-treated groups than in both short-term-treated groups but at the end of the observational period (144 h) no significant differences were found among groups. The pregnancy rate was higher in the ST group (87%) than in the other groups (LT, 63%; LTeCG, 67%; and STeCG, 58%; P< or =0.03). The ovulatory follicle emerged before sponge withdrawal in long-term-treated ewes (-3.8+/-0.4 d and -2.2+/-0.8 d for LT and LTeCG, respectively), whereas in short-term-treated ewes it emerges around sponge removal (0.4+/-1.1 d and 0.5+/-0.5 d for ST and STeCG, respectively; P< or =0.01). The ovulatory follicle in the LT group had a longer lifespan and attained a larger (P< or =0.05) maximum diameter than in the ST group. We conclude: a) that the lower pregnancy rate observed after long-term progestagen treatment was related to a slower follicular turnover that promoted the ovulation of persistent dominant follicles; (b) that short-term treatment resulted in a higher pregnancy rate probably due to the ovulation of newly recruited growing follicles; and (c) treatment with eCG had no advantage in association with long-term treatment and had a deleterious effect in combination with short-term treatment with MAP.     

Administration of 6-methoxybenzoxazolinone (MBOA) does not augment ovulatory responses in St. Croix White ewes superovulated with PMSG

The objective of this investigation was to examine the effects of 6-methoxy-benzoxazolinone (MBOA), a plant compound that resembles melatonin and alters ovarian function in rodents, in combination with PMSG on superovulatory responses in the cycling ewe. In Experiment I, St. Croix White ewes (n = 44) were synchronized (intra-vaginal progestin sponge) for 14days followed by hCG (750 IU) at 1 day after sponge removal (day 0). Ewes were assigned to one of six treatments administered on day -1: Control (no PMSG or MBOA; n = 7); PMSG (1000 IU i.m.; n = 7); Low MBOA (0.43 mg/kg i.m.; n = 7); High MBOA (1.15 mg/kg i.m.; n = 7); Low MBOA + PMSG (n = 8); High MBOA + PMSG (n = 8). In Experiment II, St. Croix White ewes (n = 24) were synchronized (progestin CIDR) for 14 days followed by hCG on day 1 after CIDR removal (day 0). Ewes were assigned to one of three treatments administered on day -1: Control (n = 8); PMSG (n = 8); Low MBOA+PMSG (n = 8). Laparoscopy was performed on day 9 to assess numbers of corpora lutea (CL) and visible follicles on each ovary. Blood samples were collected on day -13, -1, 0, 1, and days 6 or 7-12 for analysis of serum progesterone (P4) by RIA. Treatment groups receiving PMSG (alone or with MBOA) exhibited greater (P < 0.05) serum concentrations of P4 post-synchrony than Control and MBOA-only groups. Ovulation rate was lower (P < 0.05) for Control and MBOA-only treated ewes than ewes receiving PMSG. Ovulation rate in ewes treated with MBOA alone was similar (P > 0.10) to Controls, and PMSG treatment alone did not differ (P > 0.10) from MBOA + PMSG treatment. Ewes treated with PMSG alone did not differ (P > 0.10) in follicle number from High MBOA + PMSG treated ewes, however, Low MBOA + PMSG treated ewes had greater numbers of follicles at day 9 (P < 0.05) than the PMSG or High MBOA + PMSG groups in Experiment I; although, this was not replicated in Experiment II with numbers of follicles in the Low MBOA + PMSG group being similar (P > 0.10) to PMSG alone. In summary, the addition of MBOA in combination with PMSG as part of a synchronization-superovuation protocol in the ewe did not increase ovulation rate.     

Myogenesis in sheep is altered by maternal feed intake during the peri-conception period

The effect of varying short-term maternal feed intake during the peri-conception period on the development of ovine fetal muscle at mid-gestation was investigated. Superovulated donor Merino ewes (n = 24) were fed a roughage/grain pelleted diet (10.1 MJME/kg dry matter) at either 1.5x maintenance (H; high) or 0.5x maintenance (L; low) from 18 days before until 6 days after ovulation. Embryos were transferred to recipient ewes (n = 60) on day 6. Singleton fetuses were collected on day 75 of gestation and placental weights, fetal body dimensions and fetal organ and muscle weights recorded. The number, type and size of muscle fibres and the dry matter, RNA, DNA and protein content in the semitendinosus muscle were determined. Maternal feed intake did not influence body dimensions, organ development or muscle weights in the fetus. However, L feed intake decreased total muscle fibre number in the fetus by approximately 20% (P = 0.06) compared to H feed intake. This resulted from a reduced secondary to primary fibre ratio (P < 0.05) and indicated that secondary fibre formation occurred at a reduced rate in L fetuses. In addition, protein:DNA ratio tended to be lower in muscles of L fetuses (P < 0.1). It is concluded that restricting feed intake over the peri-conception period reduces or delays myogenesis in fetal sheep. The potential mechanisms by which nutritional availability during this period may influence subsequent myogenic development are discussed.     

Effect of copper- and zinc-methionine supplementation on bioavailability,mineral status and tissue concentrations of copper and zinc in ewes

The effect of feeding Cu- and Zn-methionine to ewes was studied in a 240d feeding trial. The plasma and tissue Cu and Zn concentrations and Cu/Zn-superoxide dismutase (Cu/Zn-SOD) activity were employed to assess the relative bioavailability from Cu- and Zn-methionine. The macro and micronutrient intake, utilization, plasma mineral status, tissue accumulation of Cu and Zn as well as wool concentration of Cu and Zn were studied in ewes (n=12) fed a corn-soybean meal based basal diet with 50% more Cu and Zn supplementation over the basal diet either from Cu- and Zn-sulfate (Cu-Sulf+Zn-Sulf group) or Cu- and Zn-methionine (Cu-Meth+Zn-Meth group). The average daily feed intake and body weight gain of ewes did not differ due to dietary supplementation of Cu- and Zn-methionine. However, dry matter intake was comparatively lower and thus resulted in better feed: gain in Cu- and Zn-methionine group as compared to ewes fed Cu- and Zn-sulfate. Supplementation of Cu and Zn over the basal diet either from methionine-chelated or sulfate sources resulted in increased plasma Cu and Zn as well as Cu/Zn-SOD activity on d-30, which indicated a positive correlation between plasma Cu and Zn and Cu/Zn-SOD activity. The gut absorption, liver concentrations of Cu and Zn, and liver Cu/Zn-SOD activity were significantly (P<0.01) higher in ewes supplemented with Cu- and Zn-methionine compared to Cu- and Zn-sulfate. Periodical analysis of wool samples indicated no significant difference in Cu and Zn content between Cu-and Zn-methionine and Cu- and Zn-sulfate groups. Feeding of Cu and Zn from methionine-chelated source resulted in reduced (P<0.01) excretion of Cu and Zn in feces indicating their better utilization, and this will have positive implication on environment. The gut absorption values, plasma and liver tissue concentrations of Cu and Zn supported the hypothesis that Cu- and Zn-methionine supplements have better bioavailability compared to Cu- and Zn-sulfate and Cu- and Zn-dependent enzyme (Cu/Zn-SOD) could be used to determine the bioavailability of Cu and Zn.     

Effect of undernutrition in foetal life on energy expenditure during gestation in ewes

The long-term effect of early life undernutrition on late gestation energy expenditure (EEgest) was investigated in sheep. Ewes were fed either adequate (100%) or restricted (60%) energy and protein during late foetal life as well as during last trimester of gestation later in life, resulting in three groups: Adequate-Adequate (AA, n = 5), Adequate-Restricted (AR, n = 5) and Restricted-Restricted (RR, n = 5). At two weeks pre-partum, EEgest were calculated from respiratory gaseous exchange and nitrogen excreted in urine and further it was partitioned to energy expenditure for conceptus development (EEconceptus) and homeorhetic adaptations in maternal metabolism (EEhomeorhetic). Late gestational energy and protein restriction reduced the EEgest in the AR ewes (4.1 MJ x d(-1)) but not in the RR ewes (5.2 MJ x d(-1)) compared with the AA ewes (6.8 MJ x d(-1)). Based on conceptus-weight, no significant difference was found in EEhomeorhetic among the groups; 172, 175 and 169 kJ/kg x d(-1) in AA, AR and RR ewes, respectively. However, EEconceptus was significantly lower in AR (135 kJ/kg x d(-1)) in comparison with AA (298 kJ/kg x d(-1)) and RR (252 kJ/kg x d(-1)) ewes. In conclusion, exposure nutrient restriction in early life impairs the ability of ewes to respond to nutritional restriction in terms of energy expenditure of gestation.     

Ovarian antral follicular dynamics and their relationships with endocrine variables throughout the oestrous cycle in breeds of sheep differing in prolificacy.

Transrectal ultrasonography of ovaries was performed each day in non-prolific Western white-faced (n = 12) and prolific Finn ewes (n = 7), during one oestrous cycle in the middle portion of the breeding season (October-December), to record the number and size of all follicles > or = 3 mm in diameter. Blood samples collected once a day were analysed by radioimmunoassay for concentrations of LH, FSH and oestradiol. A cycle-detection computer program was used to identify transient increases in concentrations of FSH and oestradiol in individual ewes. Follicular and hormonal data were then analysed for associations between different stages of the lifespan of the largest follicles of follicular waves, and detected fluctuations in serum concentrations of FSH and oestradiol. A follicular wave was defined as a follicle or a group of follicles that began to grow from 3 to > or = 5 mm in diameter within a 48 h period. An average of four follicular waves per ewe emerged during the interovulatory interval in both breeds of sheep studied. The last follicular wave of the oestrous cycle contained ovulatory follicles in all ewes, and the penultimate wave contained ovulatory follicles in 10% of white-faced ewes but in 57% of Finn ewes. Transient increases in serum concentrations of FSH were detected in all animals and concentrations reached peak values on days that approximated to follicle wave emergence. Follicular wave emergence was associated with the onset of transient increases in serum concentrations of oestradiol, and the end of the growth phase of the largest follicles (> or = 5 mm in diameter) was associated with peak serum concentrations of oestradiol. Serum FSH concentrations were higher in Finn than in Western white-faced ewes during the follicular phase of the cycle (P < 0.05). There were no significant differences in serum concentrations of LH between Western white-faced and Finn ewes (P > 0.05). Mean serum concentrations of oestradiol were higher in Finn compared with Western white-faced ewes (P < 0.01). It was concluded that follicular waves (follicles growing from 3 to > or = 5 mm in diameter) occurred in both prolific and non-prolific genotypes of ewes and were closely associated with increased secretion of FSH and oestradiol. The increased ovulation rate in prolific Finn ewes appeared to be due primarily to an extended period of ovulatory follicle recruitment.     

Effects of adrenalectomy on serum concentrations of progesterone during the luteal phase of sheep

An experiment was conducted to test the hypothesis that the adrenal gland influences luteal activity in sheep. Twelve Finnish Landrace x Southdown ewes were either bilaterally adrenalectomized (n = 6) or sham adrenalectomized (n = 6) during the breeding season. At approximately 37 and 47 d after surgery, all ewes received intramuscular injections of cloprostenol to synchronize estrus. Blood samples were taken via jugular venipuncture at 48-h intervals between 1 and 19 d after the last cloprostenol treatment. Serum concentrations of progesterone were determined in each of these samples. Analysis of variance showed that concentrations of progesterone during the luteal phase were lower (P<0.05) in adrenalectomized ewes than in sham-operated controls, but that patterns of progesterone were similar for both groups of sheep. Based on these results, we conclude that the adrenal gland does not appear to be necessary for initiation of luteal regression in ewes.     

顺铂化疗对下丘脑、血浆ghrelin和orexin 表达的影响

目的:观察顺铂化疗对下丘脑、血浆ghrelin、orexin表达和摄食量的影响。方法:Real-time PCR、ELISA法观察顺铂对大鼠下丘脑、血浆ghrelin、orexin表达及摄食量的影响;19名接受顺铂经导管动脉灌注化疗(TAI)的肝细胞患者(HCC),ELISA法检测化疗前和化疗后血浆ghrelin、orexin的变化,用直观类比标度(VAS)(0-10)评估食欲和摄食量。结果:每日腹腔注射顺铂6 mg/kg,1-5 d大鼠摄食量均显著减少(P0.05),且1-4 d血浆酰化ghrelin显著降低(P0.05),5d时浓度仍低于对照组,但无统计学意义。血浆非酰化ghrelin和总的血浆ghrelin没有明显变化(P0.05),而1-5天血浆orexin水平均明显降低(P0.05);顺铂注射1 d后,大鼠下丘脑ghreilin和orexin的mRNA表达量均显著减少(P0.05),ghrelin mRNA变化持续3 d,orexin mRNA在化疗后5 d仍低于对照组(P0.05);肝细胞癌患者化疗后1至8 d的摄食量明显降低,1 d和2 d时的血浆酰化ghrelin显著低于化疗前水平(P0.05)。3 d时逐渐恢复,化疗后3 d、4 d和7 d时血浆酰化ghrelin浓度与化疗前无统计学差异(P0.05)。血浆非酰化ghrelin和总的血浆ghrelin没有明显变化(P0.05);化疗后1~4 d时血浆orexin浓度均显著降低(P0.05),化疗后7 d时orexin基本恢复到化疗前水平(P0.05)。结论:顺铂可降低大鼠下丘脑和血浆ghrelin、orexin的mRNA表达,HCC的TAI会降低血浆酰化ghrelin、orexin、和摄食量。     

Melatonin-improved reproductive performance in sheep bred out of season

The effects of melatonin implants on out-of-season breeding in New Zealand Romney composite ewes, was determined by comparison of reproductive performance in ewes treated with progesterone+equine chorionic gonadotrophin (eCG) (control; n=107), melatonin+progesterone+eCG (n=97) or melatonin+progesterone (n=96). Conception rates in melatonin+progesterone+eCG-treated ewes (67%) were higher than in the control ewes (P<0.01; 47%). Pregnancy rates were higher in melatonin+progesterone+eCG-treated ewes (55%; P<0.001) compared with the control ewes (40%). Fewer melatonin+progesterone-treated ewes displayed oestrus (14%; P<0.001) and subsequently became pregnant (6%). Oestrus rates in melatonin+progesterone-treated ewes (14%) were lower than both the melatonin+progesterone+eCG-treated (82%) and control ewes (86%; P<0.001), which were similar to each other. The number of foetuses per pregnant ewe was similar in all three treatment groups. Serum melatonin concentrations at Day -9 were higher in the ewes treated with melatonin and there was a large variation between individual ewes, but concentrations were similar for pregnant and nonpregnant ewes. The combination of higher conception rate and the trend for more lambs per pregnant ewes resulted in more lambs being born per ewe treated in melatonin+progesterone+eCG-treated ewes compared to the other two treatment groups. These results suggest that melatonin implants, in conjunction with administration of progesterone and eCG, may be suitable as a means of increasing the number of lambs born per ewe treated in an out-of-season breeding program in New Zealand sheep flocks while melatonin and progesterone is not.     

Acylated ghrelin secretion is acutely suppressed by oral glucose load or insulin-induced hypoglycemia independently of basal growth hormone secretion in humans

BACKGROUND: Ghrelin has been reported to be the natural ligand of growth hormone (GH) secretagogue receptor, and it is known that exogenous ghrelin administration strongly stimulates GH release in humans. However, the effects of endogenous ghrelin on GH secretion and changes in ghrelin levels during dynamic changes in GH levels are not well understood. METHODS: Therefore, we measured circulating acylated ghrelin concentrations during oral glucose tolerance tests (OGTTs) in patients with active acromegaly (AA, n = 9) and in age/sex/BMI-matched group A controls (n = 12), and during insulin tolerance testing (ITT) in patients with GH deficiency (GHD, n = 10) and in group B controls (n = 10). Plasma acylated ghrelin, serum GH, insulin and glucose levels were measured during each test. RESULTS: Fasting plasma ghrelin levels correlated negatively with serum insulin levels in both group A and B controls (r = -0.665; p < 0.05) but not in patients with AA or GHD. During OGTTs, circulating ghrelin levels decreased significantly with a nadir at 30 min in both patients with AA (p < 0.05) and group A controls (p < 0.01). Also, ITTs were followed by a significant decrease in circulating ghrelin levels with a nadir at 30 min in patients with GHD (p < 0.05) and in group B controls (p < 0.05). CONCLUSION: The results of the study show that at baseline acylated ghrelin levels do not differ with respect to the GH status (GH excess or GH deficiency) and, furthermore, the suppression of acylated ghrelin levels during OGTT or ITT is independent of the GH response to the tests.     

The effect of oestradiol on postpartum uterine involution in sheep

The present study tested the hypothesis that ovarian oestradiol increases the rate of uterine involution after parturition in sheep. The day after parturition, ewes were randomly assigned as un-operated controls (n=5), or a 3 cm silastic implant containing oestradiol (n=8) or empty (n=7) was sutured within the bursa of the ovary ipsilateral to the previously gravid uterine horn. Blood samples were collected daily for measurement of PGFM and acute phase proteins until 17 days postpartum when the ewes were slaughtered and the genital tract was collected. There was no consistent effect of treatment group on uterine involution determined by the collagen density, dry matter content, width, length, or weight of the genital tract. Furthermore, there was no evidence of a localised effect of oestradiol on involution as there were no significant differences between the previously gravid and non-gravid uterine horns. However, oestradiol-treated ewes had lower plasma concentrations of 15-keto-13,14-dihydro-prostaglandin F2alpha (P<0.01), alpha1-acid glycoprotein (P<0.05) and ceruloplasmin (P<0.001); but, not haptoglobin. These observations could reflect a direct effect of oestradiol on inflammatory mediator synthesis or secretion because, in the absence of parallel physical measurements, it is unlikely that these observations reflect a beneficial effect of treatment on uterine health.