Histology,ultrastructure, and seasonal variations in the bulbourethral gland of the African straw-colored fruit bat Eidolon helvum

We studied the morphological characteristics and seasonal changes of the bulbourethral gland of Eidolon helvum in a typical African tropical environment. Forty-eight bulbourethral glands were examined using gross anatomical, histological, histochemical, and ultrastructural techniques during the early rainy, late rainy, and peak dry seasons. The pear-shaped bilateral bulbourethral glands were located extra-abdominally in the inguinal region. Trabeculae from the capsule divided the parenchyma into numerous lobules of tubuloalveolar glandular acini. The mucosa was covered by a simple columnar epithelium consisting up of principal secretory cells, columnar dense cells and basal cells, which were progressively pronounced during the dry season. The principal cells contained eosinophilic granules, which were PAS positive while the dense cells did not show affinity for the stains. The mean gross weights, acini diameters, and epithelial heights were greater during the rainy season than the dry season. Ultrastructural evaluation showed that the cytoplasm of the principal cells contained well-developed Golgi complexes, rough endoplasmic reticulum, mitochondria, and secretory vesicles of varying electron densities and sizes. The secretory vesicles were numerous during the early rainy season, decreased during the late rainy season and were scanty during the peak dry season. The simple columnar epithelium observed during the rainy season was replaced by an undefined stratified epithelium during the dry season, and this was associated with cellular degenerations and regenerations. In conclusion, E. helvum has a typical mammalian bulbourethral gland, with a unique cell type, the dense cell whose functions are not well-understood. The gland exhibits cyclical seasonal variation in structure and secretory activity; being active during the early rainy season (breeding season), and showing the lowest activity during the dry season (non-breeding season). Glandular epithelial cell renewal occurs during the dry season in preparation for the next breeding season.     

Effect of advancing the supply of finisher diet on growth performances and carcass and pork quality of heavy barrows and gilts

A total of 120 Duroc×(Large White×Landrace) pigs, 50% barrows and 50% gilts, with 54.1±0.14 kg BW and 103±3 days of age, were used to study the effect of advancing the shift to a standard finisher feed from 100 to 90 and 80 kg BW on production performances and carcass and pork quality. Each of the six treatments (two sexes×three BWs at time of feeding shift) was replicated four times and the experimental unit was the pen (with five pigs for growth performance and carcass variables and three pigs for pork and fat traits). The grower (163 g CP and 9.5 g total Lys/kg) and the finisher diets (152 g CP and 7.9 g total Lys/kg) were based on maize, barley and vegetal protein concentrates, contained 13.39 MJ metabolizable energy/kg and were offered ad libitum through the trial. Pigs intended for dry-cured product elaboration were slaughtered at 170±3 days of age as average (124 and 115 kg BW for barrows and gilts, respectively). For the overall period, barrows ate more feed (P<0.001) and grew faster (P=0.03) than gilts. No effect of feed shift was observed on growth performances, although the average daily CP intake (P=0.01) and feeding costs (P=0.04) were reduced by advancing the transition to the finisher feed. Carcasses from barrows were heavier (P<0.001) and had wider backfat depth (P<0.001) than those from gilts but no significant differences were observed in the meat chemical composition. The feed change schedule did not modify carcass or meat traits. It is concluded that an early shift to the finisher feed (at 80 kg BW instead of 100 kg BW) might be an interesting strategy in pigs intended for dry-cured products because, although it neither increased body fatness nor improved pork quality, CP intake and feeding costs were reduced without impairment of growth performances. Results were similar for barrows and gilts.     

Hydrolysable tannin-based diet rich in gallotannins has a minimal impact on pig performance but significantly reduces salivary and bulbourethral gland size

Tannins have long been considered ‘anti-nutritional’ factors in monogastric nutrition, shown to reduce feed intake and palatability. However, recent studies revealed that compared with condensed tannins, hydrolysable tannins (HT) appear to have far less impact on growth performance, but may be inhibitory to the total activity of caecal bacteria. This in turn could reduce microbial synthesis of skatole and indole in the hindgut of entire male pigs (EM). Thus, the objective of this study was to determine the impact of a group of dietary HT on growth performance, carcass traits and boar taint compounds of group housed EM. For the study, 36 Swiss Large White boars were assigned within litter to three treatment groups. Boars were offered ad libitum one of three finisher diets supplemented with 0 (C), 15 (T15) or 30 g/kg (T30) of HT from day 105 to 165 of age. Growth performance, carcass characteristics, boar taint compounds in the adipose tissue and cytochrome P450 (CYP) isoenzymes CYP2E1, CYP1A2 and CYP2A19 gene expression in the liver was assessed. Compared with C, feed efficiency but not daily gain and daily feed intake was lower (P<0.05) in T15 and T30 boars. Except for the percentage carcass weight loss during cooling, which tended (P<0.10) to be greater in T30 than C and T15, carcass characteristics were not affected by the diets. In line with the numerically lower androstenone level, bulbourethral and salivary glands of T30 boars were lighter (P<0.05) than of T15 with intermediate values for C. Indole level was lower (P<0.05) in the adipose tissue of T30 than C pigs with intermediate levels in T15. Skatole levels tended (P<0.10) to be lower in T30 and C than T15 pigs. Hepatic gene expression of CYP isoenzymes did not differ between-treatment groups, but was negatively correlated (P<0.05) with androstenone (CYP2E1 and CYP1A2), skatole (CYP2E1, CYP2A) and indole (CYP2A) level. In line with the numerically highest androstenone and skatole concentrations, boar taint odour but not flavour was detected by the panellists in loins from T15 compared with loins from C and T30 boars. These results provide evidence that HT affected metabolism of indolic compounds and androstenone and that they affected the development of accessory sex glands. However, the effects were too small to be detected by sensory evaluation.     

Haematological and immunological adaptations of non-pregnant,non-lactating dairy cows to a high-energetic diet containing mycotoxins

Diet change and fatness are supposed to challenge the immune system of the cow. Therefore, immunological and haematological consequences of adaptation to and continued feeding of a high-energy diet were studied in eight non-pregnant, non-lactating Holstein cows over 16 weeks. Blood haptoglobin concentration remained unaltered, suggesting that an acute phase reaction was not induced. Stimulation ability of peripheral blood mononuclear cells and stimulated oxidative burst capacity of granulocytes increased significantly in the course of the experiment after an initial drop. While total leucocyte counts increased, the proportion of granulocytes increased and that of lymphocytes decreased at the same time as the ratio of CD4⁺/CD8⁺ lymphocytes did. Capability of rumen microbes to detoxify the immune-modulating mycotoxin deoxynivalenol (DON) was not compromised as indicated by the exclusive presence of de-DON as the detoxified DON metabolite in blood. In conclusion, both diet change and prolonged positive energy balance influenced the bovine immune system.     

Analysis of theFusarium toxins Deoxynivalenol and Zearalenone in Austrian feeds of the crop years 2002 and 2003

164 feed samples were collected in Lower Austria, Upper Austria, Styria and Carynthia in the crop years 2002 and 2003 and were analysed by means of the RIDASCREEN^® ELISA-assay for theFusarium toxins Deoxynivalenol (DON) and Zearalenone (ZON). The collected samples consisted of swine feeds, cereals and silages. DON concentrations were found up to the range of mg/kg (ppm), in contrast ZON results remained significantly lower.     

A case report on a minor contamination of nivalenol in cereals harvested in Canada

An investigation for the occurrence of nivalenol (NIV), deoxynivalenol (DON) and zearalenone (ZEN) in cereals (ten wheat, one rye and one corn) harvested in Canada have been carried out using a procedure, which is rapid and sensitive for Fusarium mycotoxins. NIV, DON and ZEN were detected in 4, 9 and 9 out of ten wheat samples, and their average levels in the positives were 23 ng/g, 1257 ng/g and 9 ng/g, respectively. One rye and one corn were also contaminated with a minor amount of NIV. This is the first evidence for the natural occurrence of NIV in cereals grown in Canada, though its level was far less than DON.     

Response of 40-70 kg barrows and gilts to increasing ideal protein concentrations in the diet

In Belgium, crossing a hybrid dam with a Piétrain sire leads to a rather lean and meaty fattening pig type. A digestibility trial and a performance trial were carried out to determine protein needs of this pig type. Six experimental diets with increasing protein content were formulated with 0.65-1.25% apparent ileal digestible lysine. The feeds were formulated to the ideal protein composition, with lysine as the reference amino acid. Standardised and apparent digestible amino acid values of the extreme diets were measured in a digestibility trial with four gilts cannulated at the end of the ileum, with an average initial and final BW of 39.1 kg and 55.3 kg, respectively, using a protein-free feed to estimate the basal endogenous N-losses. A performance trial at 13-18 weeks of age (40-70 kg BW) was performed with barrows and gilts separately at six protein levels, balanced in lysine, threonine, methionine and tryptophan. The experiment consisted of 11 pens (of 5 animals) per treatment and per sex. Average daily gain (ADG) and feed conversion ratio (FCR) reached maximal performance within the experimental lysine range for both sexes. Based on the ADG-data for barrows and on the ADG- and FCR-data for gilts, a protein level for optimal performance corresponded with a standardised ileal digestible lysine concentration of 0.89% for barrows and of 1.07-1.09% for gilts.     

Effects of starvation,chilling, and injury on endocrine gland function in Galleria mellonella

Starvation, chilling, and injury of last instar Galleria mellonella larvae typically elicit extra larval molts or a delay in pupation. The primary sites of action and the nature of the signals by which these treatments affect development are not known. However, since the connections of the brain to the nerve cord are crucial for the effects of starvation and chilling, these signals apparently affect the brain-centered program of developmental regulation via the nerve cord. Chilling, and occasionally starvation, cause extra larval molts in last instar larvae treated prior to the nervous inhibition of their corpora allata; release of a cerebral allatotropin, which stimulates the production of juvenile hormone, appears to be involved in this effect. After this time, a delay in pupation is the principal effect of starvation and chilling, and is apparently due to a temporal inhibition of the release of the prothoracicotropic hormone. Chilling also appears to inhibit unstimulated ecdysteroid production by the prothoracic glands. The effect of injury is not mediated by the nerve cord, but appears to involve an inhibitory humoral factor that affects either the brain or the prothoracic glands themselves. Injury also stimulates juvenile hormone production, an effect which is enhanced when the brain is separated from the nerve cord and which is evidenced by a delay of ecdysis and the occasional retention of some larval features in the ecdysed insects. None of the effects of these various treatments on the brain and the endocrine glands persist when the brains or glands are implanted into untreated hosts.     

Effects of a Fusarium toxin-contaminated maize treated with sodium metabisulphite,methylamine and calcium hydroxide in diets for female piglets

Deoxynivalenol (DON) and zearalenone (ZEN) contaminated maize was hydrothermally treated in the presence of sodium metabisulphite (SBS), methylamine and calcium hydroxide (Ca(OH)₂) and included into diets for female piglets to evaluate effects on performance, organ weights, development of hyperestrogenism, serum biochemical parameters, stimulation of peripheral blood mononuclear cells and toxin residues in serum. For this purpose, both uncontaminated maize (CON) and Fusarium toxin-contaminated maize (FUS) were included into diets either untreated (?) or treated (+) according to a 2 by 2-factorial design. One-hundred female weaned piglets were assigned to one of the four treatment groups (n = 25) CON?, CON+, FUS? and FUS+ with DON/ZEN concentrations of 0.43/0.03, 0.04/0.0, 3.67/0.32 and 0.36/0.08 mg per kg diet, respectively. After a feeding period of 27 days, 20 piglets (n = 5) were slaughtered. Performance parameters such as feed intake, live weight gain and feed-to-gain ratio remained unaffected by the treatments. Uterus weights were significantly reduced in group FUS+ compared to FUS? (p = 0.028), while visceral organ weights were not influenced. Vulva width in relation to body weight was highest in group FUS? at the end of the trial, while hydrothermal treatment significantly reduced the parameter (p < 0.01). The highest toxin and toxin metabolite concentrations in serum were detected in group FUS?, whereas ingestion of diet FUS+ reduced the concentrations to the level of the control groups. Serum biochemical and haematological parameters were mainly within the given reference ranges and showed no treatment-related alterations. Stimulation of peripheral blood mononuclear cells was not affected. An effective detoxification of maize by hydrothermal treatment in the presence of SBS, methylamine and Ca(OH)₂ could be demonstrated by means of serum toxin analyses. No undesired side effects of the treated-feed stuff or the chemicals themselves on the health of piglets were detected.     

Effects of two different anaesthetics on serum concentrations of cortisol and luteinizing hormone in barrows and gilts

To determine if administration of the anaesthetic cocktail, telazol-ketamine-xylazine (TKX) and pentothal (PEN) decreases serum concentrations of luteinizing hormone (LH) in pigs, the following experiment was performed. On day 1, eight gilts and six barrows of similar weight (75 kg) were anaesthetized with TKX (1 mL/22.5 kg body weight [BW] intramuscularly) and indwelling jugular catheters were inserted. On days 2, 6 and 8 blood samples were taken every 20 min, for 4 h before pigs were administered saline (day 2) or anaesthetized with TKX (day 6) and PEN (8.9 mg/kg BW intravenously, day 8). Blood samples were taken every 20 min for 4 h following administration of saline and anaesthetics. Mean serum concentrations of LH and cortisol did not differ (P > 0.05) within barrows or gilts from before administration of saline (day 2) to following saline administration. Mean serum concentrations of LH and cortisol were not different (P > 0.05) within barrows and gilts before administration of TKX (pre-TKX) or PEN compared with day 2 samples. Following administration of TKX (post-TKX), mean serum concentrations of LH decreased (P < 0.05) and remained decreased for 140 min, while mean serum concentrations of cortisol increased (P < 0.05) post-TKX and remained elevated for 140 min. In gilts, mean serum concentrations of LH did not differ (P > 0.05) from pre- to post-TKX. However, mean serum concentrations of cortisol increased (P < 0.05) post-TKX in gilts and remained elevated for 240 min. Following administration of PEN, mean serum concentrations of LH and cortisol within barrows and gilts were not different (P > 0.05) from concentrations before administration of PEN. Administration of TKX to barrows and gilts increased serum concentrations of cortisol, but transient decreases in serum concentrations of LH were observed only in barrows, indicating gonadal status and/or sex may influence the ability of TKX to alter circulating concentrations of LH in pigs.     

Effects of dietary l-arginine supplementation to gilts during early gestation on foetal survival, growth and myofiber formation

The effects of l-arginine on porcine foetal development and myogenesis were determined. Twenty Swiss Large White gilts were randomly allocated to either the control (C) or l-arginine treatment (A). In addition to the standard gestation diet, A-sows received 26 g l-arginine daily from days 14 to 28 of gestation. At day 75 of pregnancy, sows were sacrificed and the number and weight of foetuses were recorded. From each litter, the lightest, heaviest and the ones with an average foetal weight (FtW) were selected. Primary (P), secondary (S) and total myofiber number as well as S/P ratio were determined in the semitendinosus (ST) and rhomboideus (RH) muscles. In A-sows, the number of viable foetuses (13.0 v. 9.3) and total FtW (4925 v. 3729 g) was greater (P ⩽ 0.04) than in C-sows. Compared to C-sow foetuses, the ST of A-sow foetuses had 7% more (17 699 v. 16 477; P = 0.04) P myofibers and the S/P ratio in both muscles was lower (ST = 20.3 v. 21.5; RH = 24.1 v. 27.1; P ⩽ 0.07). Regardless of the maternal diet, the S myofiber number and the S/P ratio in both muscles were greater (P ⩽ 0.01) in foetuses with a high FtW compared to low FtW. These data suggest that l-arginine supplemented to gilts during early gestation enhanced foetal survival and in the ST positively affected the primary phase of myofiber formation.     

Effect of dam weight and pregnancy nutrition on average lactation performance of ewe offspring over 5 years

The foetal mammary gland is sensitive to maternal weight and nutrition during gestation, which could affect offspring milk production. It has previously been shown that ewes born to dams offered maintenance nutrition during pregnancy (day 21 to 140 of gestation) produced greater milk, lactose and CP yields in their first lactation when compared with ewes born to dams offered ad libitum nutrition. In addition, ewes born to heavier dams produced greater milk and lactose yields when compared with ewes born to lighter dams. The objective of this study was to analyse and compare the 5-year lactation performance of the previously mentioned ewes, born to heavy or light dams that were offered maintenance or ad libitum pregnancy nutrition. Ewes were milked once per week, for the first 6 weeks of their lactation, for 5 years. Using milk yield and composition data, accumulated yields were calculated over a 42-day period for each year for milk, milk fat, CP, true protein, casein and lactose using a Legendre orthogonal polynomial model. Over the 5-year period, ewes born to heavy dams produced greater average milk (P=0.04), lactose (P=0.01) and CP (P=0.04) yields than offspring born to light dams. In contrast, over the 5-year period dam nutrition during pregnancy did not affect average (P>0.05) offspring milk yields or composition, but did increase milk and lactose accumulated yield (P=0.03 and 0.01, respectively) in the first lactation. These results indicate that maternal gestational nutrition appears to only affect the first lactational performance of ewe offspring. Neither dam nutrition nor size affected grand-offspring live weight gain to, or live weight at weaning (P>0.05). Combined these data indicate that under the conditions of the present study, manipulating dam weight or nutrition in pregnancy can have some effects of offspring lactational performance, however, these effects are not large enough to alter grand-offspring growth to weaning. Therefore, such manipulations are not a viable management tool for farmers to influence lamb growth to weaning.     

Effect of a low calcium diet on the ultrastructure of the parathyroid gland of chicks

Summary The effect of a low calcium diet on the ultrastructure of the parathyroid gland in the chick was examined. Two-week-old White Leghorn chicks were fed a low calcium diet (calcium content 0.63%) for two weeks. In these chicks, the parathyroid glands are grossly enlarged. Hypertrophy and hyperplasia of the chief cells are evident. The plasma membranes between adjacent cells are relatively straight but interdigitate in some places. Chief cells contain occasional membrane-limited secretory granules (150–350 m in diameter) and with contents of variable electron density. Secretory granules are distributed randomly but some are closely applied to the plasma membrane. There is an increase in the development of the rough-surfaced endoplasmic reticulum. The Golgi complex is enlarged and consists of cisternae arranged in concentric layers, smooth-surfaced and coated vesicles and condensing vacuoles. Dilatations of the cisternae at several points are observed. Mitochondria and filaments are also encountered. These morphological features suggest that low calcium intake stimulates the synthetic activity of the chief cells of the chick parathyroid.     

Influence of organically or conventionally produced wheat on health,performance and mycotoxin residues in tissues and bile of growing pigs

From 1999?–?2001 three different varieties of wheat [Contur (susceptible to Fusarium), Batis and Petrus (less susceptible to Fusarium)] were cultivated under organic and conventional conditions in order to determine mycotoxin burden. Soil quality, preceding crop and weather conditions were comparable in the different production systems. The wheat batches were analysed for moulds, and the contents of zearalenone (ZEN) and deoxynivalenol (DON). Feeding trials were carried out with growing pigs (n?=?96; average initial live weight 22.2 ±?1.5?kg [mean?±?SD]) to examine a possible influence on the animal performance and on mycotoxin residues. The data recorded were clinical conditions, performance, biochemical and hematological data. Residues of ZEN, α- and β-zearalenol (ZEL) and of DON were determined in bile, liver and muscle after slaughtering. Conventionally cultivated wheat was more frequently contaminated with Fusarium and contained more frequently ZEN and DON in higher concentrations than the organically produced wheat. Hematological and biochemical parameters of pigs fed with organically cultivated diets were not different from those of conventionally fed pigs. Pigs fed with organically produced wheat showed a slightly higher daily weight gain, but a lower carcass yield than the conventionally fed animals. The highest residues of DON and total-ZEN (ZEN + α-ZEL + β-ZEL) were found in bile. Bile samples of organically fed pigs contained lower concentrations of total-ZEN than those of conventionally fed pigs. Altogether, these data suggest that wheat from an organic farming does not have higher mycotoxin-contamination than wheat from the conventional farming system.     

Effects of Field Application of Tebuconazole on Yield, Yield Components and the Mycotoxin Content of Fusarium-infected Wheat Grain

Winter wheat cultivar Basalt was artificially inoculated with Fusarium culmorum at the end of anthesis and treated with the systemic fungicide tebuconazole (Folicur^®) a few days before and/or after inoculation. Check plots remained uninoculated and unsprayed. Head infections, yield, yield components and the percentage of Fusarium‐ infected kernels were determined. Artificial Fusarium inoculation lowered yield significantly by 24.2‐45.0%. Any fungicide treatment saved yield, thousand grain weight and kernel numbers per head. Pre‐infectional application of tebuconazole was superior to application carried out post‐infection. Moreover, the fungicide controlled deoxynivalenol (DON) synthesis in the field to a considerable extent, and enabled good control of Fusarium head blight, glume blotch and the percentage of Fusarium‐infected kernels. The levels of Fusarium kernel infection after harvest clearly reflected the DON content of w heat grain.     

The effects of immunization against gonadotropin-releasing hormone on growth performance,reproductive activity and carcass traits of heavy weight gilts

Heavy weight gilts commonly show signs of oestrus during the late finishing phase, which results in a period of reduced feed intake and growth rate. Immunization against gonadotropin-releasing hormone (GnRH) (IM, immunocastration) was developed for finishing boars and recently extrapolated to females. Immunocastration acts by suppressing reproductive activity and improving the growth potential. The objective of this study was to evaluate the effects of IM on growth performance, reproductive activity and carcass characteristics of late finishing gilts. Seventy-two gilts (63.49 ± 0.39 kg) were either injected with saline (Intact) or immunized against GnRH (Immunized). The study consisted of three experimental periods: between the first to second immunization (V1 to V2, 15 to 19 weeks of age), from the second immunization to the beginning of daily boar exposure (DBE) (V2 to DBE, 19 to 21 weeks of age) and from the beginning of DBE to slaughter (S) (DBE to S, 21 to 25 weeks of age). Immunized gilts showed an overall increase (from 15 to 25 weeks) of 3.90 kg (P < 0.05) of live weight, 56 g (P < 0.05) of average daily gain (ADG) and 250 g (P < 0.001) of average daily feed intake (ADFI). Immunized gilts had a greater ADFI (+240 g, P < 0.05) and worse feed conversion ratio (+0.26, P < 0.05) from 19 (V2) to 21 weeks of age (before DBE). Furthermore, those females had higher feed intake (+410 g; P < 0.001) plus greater daily weight gain (+92 g; P < 0.05) from V2 to S, and from DBE to S (+470 g of ADFI, P < 0.001; +129 g of ADG, P < 0.01, respectively). Immunocastration had no effect on backfat thickness, lean meat percentage and weight, cold carcass yield or loin depth (P > 0.05). Immunized gilts showed 4.4% increased cold carcass weight (P < 0.01) and 10.6% greater gross flank weight (P < 0.001). Immunization against GnRH did not influence shoulder, collar, loin, belly or ham weights. Nor did it influence belly fat thickness, or meat, skin plus fat and bones yields of cold ham (P > 0.05). Immunocastration reduced ovarian and uterine weights by 82% (P < 0.001) and 93% (P < 0.001), respectively, and suppressed oestrus manifestation in all gilts in the immunized group (P < 0.001). These results indicate that immunization against GnRH is a promising tool for stimulating growth performance with no detrimental effects on carcass quality of heavy weight finishing gilts, by means of oestrus suppression.     

乳腺发育及泌乳相关miRNA研究进展

MicroRNA(miRNA)是一种重要的转录后调控的非编码RNA, 参与调控哺乳动物乳腺发育和泌乳。文章总结了乳腺发育和泌乳过程中miRNA表达的时空特异性, 综述了个别miRNA对乳腺发育和泌乳的调节作用, 旨在为乳腺miRNA的研究提供指导, 为利用miRNA促进乳腺健康发育和调控高质高效产乳提供理论基础和研究思路。     

雷洛昔酚对大鼠垂体的作用

目的 观察雷洛昔酚是否能诱发出催乳素瘤的动物模型以及对PRL水平的影响,以研究雷洛昔酚对大鼠垂体的作用.方法 雌性Wistar大鼠切除卵巢后,分别在皮下埋植含有雷洛昔酚、雌激素和空白硅胶管,术后8周处死大鼠,检测大鼠体重变化、垂体重量变化、血清催乳素(PRL)水平和垂体组织学变化.结果 雷洛昔酚组与阴性对照组大鼠体重无明显统计学差异,与雌激素组大鼠体重具有统计学差异(P＜0.05);雷洛昔酚组与阴性对照组大鼠垂体重相比无明显差异,与雌激素组大鼠垂体重相比具有统计学差异(P＜0.05);雌激素组大鼠血清PRL水平最高,阴性对照组血清PRL水平最低,雷洛昔酚组介于两者之间,分别与雌激素组、对照组相比较差异均具有统计学意义(P＜0.05);雷洛昔酚组与对照组垂体病理为正常细胞形态,雌激素组垂体病理为PRL瘤表现.结论 雷洛昔酚对大鼠垂体有一定的影响,但不能诱发催乳素瘤.