Effects of Xenobiotics and Phytotoxins on Reproduction in Food Animals

Cerebrospinal fluid analysis in 58 ruminants showing neurological disorders

ABSTRACT: Ruminants may be affected by a wide variety of central nervous system (CNS) diseases. Cerebrospinal fluid (CSF) analysis forms the basis for ante mortem diagnostic evaluation of ruminants with clinical signs involving the CNS. Despite its importance as a tool to aid diagnosis, data regarding CSF examinations in spontaneous cases of CNS diseases in ruminants from Brazil are limited, and most reports involve experimental studies. Therefore, this study aimed to report the results of CSF analysis in 58 ruminants showing signs of neurological disorders. CSF samples for analysis were obtained from 32 cattle, 20 sheep, and 6 goats by cerebello-medullary cistern (n=54) or lumbosacral space (n=4) puncture. These ruminants showed neurological signs related to viral (n=13), mycotic (n=3), or bacterial (n=15) infections, and toxic (n=21), traumatic (n=4), or congenital disorders (n=2). CSF analysis from ruminants with viral infections presented lymphocytic pleocytosis, even though CSF showed no changes in several cases of rabies. Neutrophilic pleocytosis, cloudiness, presence of fibrin clots, and abnormal coloration were evident in the CSF of most cases of CNS bacterial infection, such as meningoencephalitis, meningitis, abscesses, myelitis, and a case of conidiobolomycosis. On the other hand, CSF was unchanged in most cases of toxic disorders, as botulism and hepatic encephalopathy. Elevated CSF density was observed in 60% of ruminants diagnosed with polioencephalomalacia. Our findings show that evaluation of CSF is a valuable diagnostic tool when used in association with epidemiological, clinical and pathological findings for diagnosis of CNS diseases in ruminants.

Leucaena leucocephala extract has estrogenic and antiestrogenic actions on female rat reproduction

Leucaena feed has been reported to cause disruptive effects on livestock reproduction, such as low calving percentages in cows, abortion in female goats and pigs, dead fetuses and fetal resorption in pregnant rats. In this study, the effects of Leucaena on different female reproductive variables were analyzed in two different reproductive conditions: gonadally intact and ovariectomized (OVX) female rats. Leucaena (LEU) was administered to females in both experimental conditions for 30 consecutive days. The effects of the legume extract were compared with those of Daidzein (DAI), a phytoestrogen, and of the female hormone estradiol (E₂). In intact females, LEU disrupted the estrous cycle and female sexual behavior, decreased the number of follicles and corpora lutea, increased uterine and vaginal epithelium in proestrus and diestrus periods, increased uterine and vaginal relative weights during diestrus, and decreased serum progesterone during proestrus. All these effects were similar to those of DAI but lower than E₂-induced effects. In OVX females, LEU decreased body weight, induced lordosis, stimulated vaginal epithelium cornification, increased vaginal weight, and augmented vaginal epithelium thickness. Again, these effects were similar to the effects of DAI and lower than the effects observed with E₂. These results indicate that, in gonadally intact females, LEU can produce antiestrogenic effects in sexual behavior but estrogenic effects on uterine and vaginal weight and epithelia, without modifying serum levels of E₂. In OVX females, in total absence of endogenous E₂, LEU induced estrogenic effects on vaginal weight and epithelia, as well as on sexual behavior.

Comparison of the effects of mesquite pod and Leucaena extracts with phytoestrogens on the reproductive physiology and sexual behavior in the male rat

Mesquite (Prosopis sp.) and Leucaena leucocephala are widespread legumes, widely used to feed several livestock species and as food source for human populations in several countries. Both mesquite and Leucaena contain several phytoestrogens which might have potential estrogenic effects. Thus, the aim of this study was to evaluate the effects of mesquite pod and Leucaena extracts on several aspects of behavior and reproductive physiology of the male rat. The effects of the extracts were compared with those of estradiol (E2) and of two isoflavones: daidzein (DAI) and genistein (GEN). The following treatments were given to groups of intact male rats: vehicle; mesquite pod extract; Leucaena extract; E2; DAI; GEN. The results indicate that mesquite pod and Leucaena extracts disrupt male sexual behavior in a similar way to DAI and GEN, but less than E2. The main disruptor of sexual behavior was E2, however after 40 and 50days of administration, both extracts and phytoestrogens disrupted sexual behavior in a similar way to E2. The extracts also increased testicular germ cell apoptosis, decreased sperm quality, testicular weight, and testosterone levels, as phytoestrogens did, although these effects were less than those caused by estradiol. The number of seminiferous tubules with TUNEL-positive germ cells increased in extracts treated groups in a similar way to phytoestrogens groups, and E2 caused the greatest effect. The number of TUNEL-positive cells per tubule increased only in Leucaena extract and E2 groups, but not in mesquite- and phytoestrogens-treated groups. Spermatocytes and round spermatids were the TUNEL-positive cells observed in all experimental groups. This effect was associated with smaller testicular weights without atrophy in experimental groups compared with control. Testicular atrophy was only observed in estradiol-treated males. Testosterone decreased in males of all experimental groups, compared with control, this androgen was undetectable in E2 treated males. These results suggest that mesquite pod and Leucaena extracts cause effects similar to those of phytoestrogens in male rat reproduction, these effects were lower than those caused by E2.