The early influence of aflatoxin upon sexual maturation in the male Japanese quail

Genotoxic and cytotoxic effects of aflatoxin on the reproductive system: Focus on cell cycle dynamics and apoptosis in testicular tissue

Aflatoxins (AFs) are inevitable environmental contaminants that are detrimental to human and animal health. AFs interfere with metabolic processes, metabolizing into different hydroxylated derivatives in the liver, as well as mechanistically induce ROS accumulation, S-phase arrest, DNA damage, and cell apoptosis. Chronic consumption of aflatoxin-contaminated foods can adversely affect the male reproductive system, cause testicular damage, prevent testosterone synthesis, decline sperm quality, and cause infertility. Oxidative stress is the fundamental pathogenesis of aflatoxin-induced reproductive toxicity. The overproduction of reactive oxygen substances can cause testicular failure and disturb the process of spermatogenesis. Mitochondria are susceptible to being impaired by oxidative stress, and its damage is associated with infertility. AFs also disturb the process of spermatogenesis by disrupting the regulation of genes related to the progression of the cell cycle such as cyclins and inducing genes related to apoptosis, thereby weakening fertility and negatively affecting the testicular endocrine potential by suppressing androgen synthesis. Additionally, AFs downregulate ERα expression, potentially negatively impacting spermatogenesis by enhancing the apoptotic mechanism. In this review, we provide new insights into the genotoxic and cytotoxic effects of AFB1 on the male reproductive system with a focus on the cell cycle and apoptosis destruction of testicular tissue.

Toxicological potential of mycotoxin MT81 and its benzoylated derivative on testicular spermatogenesis and steroidogenesis in mature male Wistar albino rats

Mycotoxin MT81 was isolated, purified, and identified from a fungal strain of Penicillium nigricans. It is a CNS depressant, hyperglycemic agent and produces massive bone marrow depression, hepatotoxicity, and nephrotoxicity. Its benzolylated analog (benzoylated-MT81) was synthesized in our laboratory having a LD₅₀ value of 87.1 mg/kg body weight in mice. This study was designed to assess the toxicological effects of mycotoxin MT81 and its analog on testicular spermatogenesis and steroidogenesis in mature albino rats. The sperm count and percentage of motile sperm were decreased markedly in MT81- and benzoylated-MT81-treated rats. The body weight and the weight of testis were reduced, whereas weight of adrenal gland was increased in a dose-dependent manner in the toxin-treated rats. MT81 and its derivative caused accumulation of ascorbic acid and total cholesterol in the testis and reduction in the activities of Δ⁵-3β-hydroxysteroid dehydrogenase (Δ⁵-3β-HSD) and glucose-6-phosphate dehydrogenase (G-6-P-D), whereas the ascorbic acid and cholesterol content of adrenal gland were decreased and enzyme activities were elevated. This experiment suggests that MT81 and benzoylated-MT81 both produce inhibition of testicular spermatogenesis and steroidogenesis but increase adrenal steroidogenesis and ultimately sterility of male rats.

Phytic Acid Exposure Alters AflatoxinB1-induced Reproductive and Oxidative Toxicity in Albino Rats (Rattus norvegicus)

The increased use of feed in Egypt's aquaculture and animal industries raises concerns about the possible presence of mycotoxins in feedstuffs. The use of alternative medicine, such as botanicals and nutritional supplements, has become popular with inflammatory cases. The present study aimed to testify the role played by phytic acid (IP6) in enhancing the reproductive and oxidative toxicity induced in aflatoxinB1 (AFB1) treated white male albino rats (Rattus norvegicus) throughout treatment and withdrawal periods. One hundred and twenty white male albino rats were grouped into four groups. Group 1, was injected with 300 μg kg⁻¹ body wt of AFB1 once every 3 days for 15 days and left uninjected for another 15 days to study the withdrawal effect. Group 2, was injected with 300 μg kg⁻¹ body wt of AFB1 once every 3 days for 15 days and treated simultaneously with IP6 daily for another 15 days. Group 3, was treated daily with IP6 (40 mg kg⁻¹ body wt) for 15 days and with no treatment for other 15 days. Group 4, injected with equivalent volume of sterile phosphate buffer saline solution as a control group. Sera were taken at the experimental intervals and assayed for testosterone hormone, follicular-stimulating hormone (FSH) and luteinizing hormone (LH) to determine the toxicological impact of AFB1 and the possibility of amelioration by phytic acid on the reproductive performance of the studied animal. The effects of AFB1 treatment on the absolute and relative weight of testis as well as its histopathologic effect on the testis and the possibility of amelioration by IP6 treatment were evaluated. The activities of enzymatic and non-enzymatic anti-oxidants, in addition to lipid peroxidation were measured in the testis’ homogenate of AFB1-treated rats. A decrease in sex hormone levels, an increase in testicular lipid peroxidation product levels and a significant decrease in testicular glutathione content, catalase and total peroxidase and superoxide dismutase activities were recorded. The histopathologic alterations revealed a degeneration and highly mitotic division within the spermatogenic nuclei, in addition to some karyomegaly and nuclear pyknosis. It is concluded that the reduction in the toxicity of free radicals by phytic acid might be responsible for the protective influence observed.

The effects of aflatoxin on the reproductive system of roosters

This study was conducted to determine the pathological changes in testes and epididymides and plasma testosterone levels of adult roosters during experimentally induced aflatoxicosis. In the study, 24 months of age, 32 Babcock breeder males were used, and they were divided into four groups each containing 8 animals. The groups were designed as follows; group 1: Control, no aflatoxin (AF), group 2: 5 ppm (parts per million) total aflatoxin (AF; B1, B2, G1, G2), group 3: 10 ppm AF and group 4: 20 ppm AF in the diet, and the birds were fed for 8 weeks. Grossly, it was seen that the testes of all AF-treatment groups birds were significantly (P < 0.001) atrophied when compared with those of control birds. Histopathologically, there was no spermatogenesis in the testes of 4, 5 and 6 cocks fed on a diet containing AF 5, 10 and 20 ppm, respectively. Furthermore, abnormal spermatozoa were observed in some of AF-treatment groups (in 2 cases in each of 5 and 10 ppm AF-treated groups, and in one case in 20 ppm AF-treated group). There were also mononuclear cell infiltration and/or focal lymphoid cell accumulation in the intertubular areas of the testes and epididymides in all AF-treatment groups. In conclusion, it has been shown that AF might totally or partially (dose related) suppress spermatogenesis, cause abnormality in spermatozoa and atrophy in testes. Furthermore, there was degeneration and desquamation in the epithelium and decrease in the size and thickness of the germinative layer of the seminiferous tubules, and lowered plasma testosterone levels in adult roosters.

Decreased reproductive potential and reduced feed consumption in mature white leghorn males fed aflatoxin

A pair-feeding study was conducted to investigate the relative importance of ingestion of aflatoxin (20 microgram/g diet) versus decreased feed consumption in explaining the effects of dietary aflatoxin on reproduction. Fifty-eight mature White Leghorn males were divided among three groups - control, 0 microgram/g diet ad lib; aflatoxin, 20 micrograms/g diet ad lib; and pair-fed, 0 microgram/g diet pair fed to 20 micrograms/g group. Aflatoxin and pair-fed males consumed significantly less feed than controls during weeks 1 through 5 of the 8-week aflatoxin feeding period. Measures of reproductive potential (semen volume, testes weights, spermatocrit, and plasma testosterone) for pair-fed males were not significantly different from males fed aflatoxin, although both groups were significantly lower than control males. Measures of aflatoxicosis (liver weight, liver fat, and plasma albumin) for pair-fed males were not significantly different from control males, although both groups were significantly different from males fed aflatoxin. In conclusion, decreased feed consumption did not produce symptoms of aflatoxicosis but accounted for 60% of the effects of aflatoxin on reproduction. Therefore, aflatoxin has nutritional and toxicological effects on reproduction.U

Delayed reproductive development resulting from aflatoxicosis in juvenile Japanese quail

Aflatoxicosis was induced in young Japanese quail. In the first experiment five replicates of 30 birds per treatment were fed a soy-corn basal ration containing 0, 5, or 10 microgram aflatoxin per gram of feed from 1 to 3 weeks of age. At 3 weeks, the animals were sacrificed and mesurements taken. In the second experiment, 0 to 10 microgram aflatoxin per gram of diet were fed from either 1 to 3 weeks of age or 2 to 4 weeks of age. At 3 weeks of age body weights were significantly (P < .05) reduced and relative liver weights were significantly (P < .05) increased. Testicular weights relative to body weight were depressed by up to 50%. Ovary wet weights, but not relative weights, were reduced. Testicular development (weight) was impaired through 6 weeks of age. Ovarian development, determined both by weight and number of developing follicles, was delayed as long as 3 weeks following withdrawal of aflatoxin from the diet. Radioimmunoassay for circulating androgens revealed that aflatoxin suppressed both the onset of production and the final concentratin of male hormone. The data demonstrate that aflatoxin can exert a deleterious inhibition of sexual development in quail with subsequent impairment of reproductive capacity. These findings raise the implication of potential reproductive failure in economically important species such as broiler breeders.