endocrinology 2011 eyes

Canis domesticus

The effect of neutering on tear production in dogs

 R Ofri¹, R Ckalifa¹, T Bdolah-Abram¹, L Shore²
Koret School of Veterinary Medicine, Hebrew University of Jerusalem, Israel¹;
Department of Endocrinology, Kimron Veterinary Institute, Ministry of Agriculture, Israel².

 Purpose: There are conflicting reports regarding gender predisposition to keratoconjunctivitis sicca (KCS), with some authors demonstrating the disease to be more prevalent in female dogs. While this finding is disputed by others, there appears to be a consensus that neutered dogs, of either gender, are predisposed to KCS, probably due to decline of sex hormones regulating tear production. Our aim was to evaluate tear production in dogs prior to, and following, neutering and to correlate it with levels of sex hormones. Methods: Study animals included 25 healthy dogs (14 females, 11 males) presented for elective neutering. Schirmer Tear Test I (STT) was performed, and blood samples for progesterone, estrogen and testosterone assays were withdrawn, on days 0 and 14. Fourteen dogs (8 females, 6 males) were re-evaluated 6 months later. Results: Mean±sd STT results on days 0, 14 and 180 were 19.7±4.4, 19.0±3.6 and 20.3±6.9 mm/min, respectively. There were no significant differences between the three readings (P=0.65), or between males and females (P=0.40). Nor was there a significant decrease in STT over time in either neutered males or females (P=0.99). No significant correlation was found between STT and any of the three hormones assayed (P>0.10). Conclusions. We believe this small scale, pilot study is the first one to measure STT over time in the same dog, prior to and following neutering. While the study needs to be repeated with a larger sample, it seems that in dogs, unlike other species, neutering has an insignificant effect on tear production.

European College of Veterinary Ophthalmologists (2011)


Capra nubiana  (pictures courtesy of Ron Ofri)
Ibex  Intraocular pressure 

Panthera leo

Ofri, R., Shore, L.S., Kass, P.H. and Horowitz, L.H. (1999). The effect of elevated progesterone levels on intraocular pressure in lions (Panthera leo). Research in Veterinary Science 67:121-123

animal endo 2011 zearalenone, phytoestrogens

Bos bovis

The effects of Zearalenone on ovarian function in dairy cows

Uzi Moallem, Moshe Kaim  Volcani Institute

It is well documented that compounds similar to estrogen in containing a phenol group can cause disturbances in the reproductive organs of various species. These estrogen-mimetics may exert their effects by two major actions: 1) binding to the estrogen receptor as an agonist; 2) binding to the estrogen receptor and preventing estrogen action (antagonist). Zearalenone is a well-known estrogen-mimetic which binds to the estrogen receptor and can decrease reproductive function in pigs, cattle and chickens.  Zearalenone has been reported to decrease conception rates and increase abortion incidence in cattle.  Similarly zearalenone is suspected to cause cyst formation in the bovine ovaries. One report was that in heifers fed 12.5 ppm of zearalenone/day, there was a reduction in the inception rate. A similar problem was reported in a milk herd which was feed with moldy hay with high concentration of zearalenone. The goal of the present experiment was to examine the effect of a known amount of zearalenone on the bovine reproductive system.  The experiment was undertaken using the experimental barn of the Volcani Institute using 12 cows which had at least one milking cycle.  Six cows were given feed containing 5 mg/day of zearalenone (Sigma) while six other cows served as a control. The zearalenone was mixed with 20 grams of ground corn and feed to the individual cows. The cows were synchronized and the ovaries were scanned for 2 consecutive cycles.  The scans recorded the follicles, corpora lutea and any ovarian abnormality. During the third cycle, follicular fluid was suctioned form the pre-ovulatory follicles. Samples of blood were taken at least once a week and more frequently in the peri-ovulatory period for estradiol determinations. No difference was observed between the groups in the size of small and intermediate follicles but the number of follicle greater than 15 mm was higher in the treated group compared to controls. Similarly the diameter and volume of pre-ovulatory follicles was greater in the treated over the control but this did not reach significance.  Analysis of the follicular fluid did not find significant differences in progesterone, androstenedione or estradiol concentrations. However the total estradiol/follicle was twofold higher in the treated compared to control (P<0.1). Similar observations were made for androstenedione and progesterone. The concentration of progesterone in the plasma on day 14 of the cycle was lower in the zearalenone treated than control (3.25 vs 6.55 ng/ml, respectively).  Examination of plasma estradiol in the peri-ovulatory showed no differences between the groups.  The data suggest that there were differences in steroid hormone production in the ovaries feed 5 mg/day zearalenone.  This was reflected in lower plasma progesterone but not plasma estradiol. Because of the high cost of the material and the intensive work schedule required, this experiment was limited to only 12 cows.  We suggest that if a larger group of cows were used, a statistical robust effect would be obtained for most of the parameters reported here.

Hebrew report  http://www.halavi.org.il/info/research/1/362-0159-08.htm

Zearalenone in the feed is sometimes associated with abortion in cows. In this unusual case, there were nearly 50 abortions in the time observed.  The peak in abortions was in second trimester.

Phytoestrogens - effects on fertility

Structure of the phytoestrogens 

Genistein and daidzein are converted to the more potent phytoestrogen equol by the intestinal bacteria.

Structure of the phytoestrogens

Plasma estrogen concentrations in cows on day of insemination in a herd feed vetch and three months after the vetch was discontinued Winter 1996).  Higher plasma estrogen was associated with higher resorption rates.

Legumes and resorption in dairy cows

Fetal resorption percentages in cows fed legumes.

Vicia sativa  vetch

Vigna unguiculata  cow peas

Resorption was determined as described in Shore, L.S., Rios, C., Marcus, S., Bernstein, M. and Shemesh, M. (1998). Relationship between peripheral estrogen concentrations at insemination and subsequent fetal loss in cattle. Theriogenology 50:101-107.  Cows were fed 1 to 3 KG of legumes/dy.  The principle phytoestrogen in cowpeas is formonentin but the phytoestrogen in vetch  could not be identified.

Here is a chart indicating that feeding vetch (a legume) to bull calves results in smaller scrotal circumference.  

Environmental 2011

Bos bovis

Soil bacteria which utilize aromatic carboxylic acids

Hermann, G., Shore, L., Steinberger, Y. (2011) Effects of cattle-lagoon slurry on a soil microbial community can be observed until depths of 50 m. Applied Soil Ecology 49 (2011): 32– 39

The large amount of effluent generated by concentrated animal feeding operations (CAFOs) has raised concerns about contamination of groundwater and pollution of streams by compounds that penetrate the vadose zone. However, the possibility that a microbial community in the vadose zone under cattle- slurry lagoons (CSLs) may also be affected has not been considered. In the present study, we investigated the influence of long-term (30 years) accumulation of cattle slurry on the vertical distribution of a soil microbial community (microbial biomass [MB], CO2 evolution, substrate utilization ability), until a 50-m depth, compared to a control site. Total soluble nitrogen (TSN) was found to be elevated fourfold, and MB was found to be threefold higher under the CSL compared to a control site. In general, the increase in MB is associated with higher soil moisture and higher nitrogen content. Substrate utilization ability was found to be significantly higher in a CSL in comparison to the control site. At the CSL site, a higher utilization of aromatic carboxylic acids typical of cattle slurry was obtained in the deeper soil layers (7–30 m), indicating a degree of microbial adaptation even at these depths. The soil layers under the CSL were more dynamic as the microbial functional diversity was significantly different between the layers, while no such difference was seen at the reference site. Our results, therefore, suggest that the infiltration of cattle slurry can affect the microbial community throughout the vadose zone. We also suggest that activity of the microbial community, as characterized by its substrate utilization ability, can be a bioindicator for anthropogenic activities and environmental changes even at depths below the rhizosphere (30 cm).

animal endo 2011 nematodes

Nematoda

Soil inhabiting nematodes

 Bacterivores

Acrobeloides

Cephalobus

Fungivores

Aphelenchus

Hu, C., Hermann, G., Pen-Mouratov, S., Shore, L., Steinberger, Y. (2011) Mammalian steroid hormones can reduce abundance and affect the sex ratio in a soil nematode community.  Agriculture, Ecosystems and Environment 142 (2011): 275– 279.

The effect of mammalian steroid hormones (estradiol, estrone, progesterone, and testosterone) in environmentally relevant concentrations on a soil free-living nematode community was examined. Steroids were applied in 2.5 L water on 0.25 m2 plots in triplicate, and comparison was made with plots receiving water alone. Soil samples were taken from the 0 to 5, 5 to 10, and 10 to 20-cm soil layers. The soil free- living nematode populations were examined at zero time, 12 h, 72 h, 96 h, 120 h, and 25 d post-treatment. Testosterone, progesterone, and estrone were persistent in the soil while the estradiol rapidly dissipated. The total number of nematodes was decreased by the presence of testosterone, progesterone, or estrone but not estradiol. Testosterone, progesterone, and estrone increased the number of males in relationship to females (60:40) compared to the control and estradiol-treated plots (50:50). The presence of steroids had no consistent effect on the distribution of bacteria-feeders, plant-feeders, and omnivore-predators. We conclude that the addition of steroid hormones in the soil can reduce abundance and change the sex ratio in a free-living nematode community. This would be the first demonstration of an effect of an endocrine-active agent excreted by mammals on a free-moving terrestrial organism.

 

Diagram of head regions of a herbivore (left) and nematode bacterivore (right). In the herbivore, the mouthpart is modified into a stylet for puncturing plant cells. In the bacterivore, the mouth or stoma is a hollow tube. (from http://entomology.ifas.ufl.edu/creatures/nematode/soil_nematode.htm)

animal endocrinology 2011

1.           Ptyodactylus guttatus

Guy Sion, Hebrew University, Dept. of Ecology, Evolution & Behavior

2.           Oculina patagonica

Rachel Armoza- Zvulani, Tel Aviv University, Dept. of Zoology

3.           Mandrillus sphinx

Yael Tal-Nissim, Hebrew University Vet. School

This is about lizards not wizards.

(from Wizards of Beverly Place)

Ptyodactylus guttatus

Aggressive geckos use their left eye as this information goes directly to the aggressive right brain.  We are investigating if this agression is associated with higher hormone levels.

Oculina patagonica

In this study we compared reproductive characteristics and steroid hormone levels in the non-indigenous scleractinian coral, Oculina patagonica, inhabiting contaminated vs. uncontaminated reference sites along the Israeli Mediterranean coast. Our results indicate significantly higher steroid levels in both seawater and coral tissue samples from contaminated sites as compared to reference sites, suggesting that corals tend to accumulate steroids from the surrounding waters. Despite their higher steroid levels, corals from the contaminated sites showed reproductive potential comparable to those of the reference sites. Interestingly, a clear distinction could be seen between corals exposed to pollution for long vs. short durations, with the latter showing a failure to complete gametogenesis. This suggests that reproduction in O. patagonica is susceptible to acute rather than chronic stress. The involvement of acclimatization/ adaptation processes may explain this species tolerance, and may reflect the ability of O. patagonica to successfully invade new areas in the Mediterranean Sea. 

Armoza-Zvuloni, R., Kramarksky-Winter, E., Rosenfeld, H., Shore, L. S., Segal, R., Sharon, D., Loya, Y. (2012). Reproductive characteristics and steroid levels in the scleractinian coral Oculina patagonica inhabiting contaminated sites along the Israeli Mediterranean coast.  Marine Pollution Bulletin 64 (8): 1556-1563

http://dx.doi.org/10.1016/j.marpolbul.2012.05.020

Mandrillus sphinx

Although mandrils are an endangered species in the wild, they breed too well in captivity.  In order to determine the best contraceptive protocol using a GnRH agonist, fecal steroids were determined before and after implantation of the agonist.