不同光照周期对鸡睾酮合成的影响

为研究不同光照周期对公鸡睾酮合成的影响,试验选择120只20周龄体重相近的AA(爱拔益加)公鸡,随机分配到3个不同光照处理组,SD、CTR、LD组分别采用8L:16D、12.5L:11.5D、16L:8D光照周期,4周后采集血清和睾丸;用ELISA技术检测睾酮含量,用实时荧光定量PCR和Westernblot技术检测睾酮合成的3个关键酶(StAR、Cyp11a1、3β-HSD)表达量,HE染色观察睾丸中曲细精管横截面积。结果表明:睾酮含量随光照周期延长极显著增加(P<0.01),并伴随睾酮分泌关键酶StAR、Cyp11a1、和3β-HSD表达量极显著升高(P<0.01),曲细精管横截面积极显著增大(P<0.01)。综上,不同光照周期可通过影响睾酮合成3个关键酶表达而影响睾酮合成,随着光照时间延长,睾酮合成增加,睾丸生精功能增强。     

Protective effects of Urtica dioica seed extract in aflatoxicosis: histopathological and biochemical findings

1. The ameliorative potential and antioxidant capacity of an extract of Urtica dioica seeds (UDS) was investigated using histopathological changes in liver and kidney, measuring serum marker enzymes, antioxidant defence systems and lipid peroxidation (malondialdehyde (MDA)) content in various tissues of broilers exposed to aflatoxin (AF).

2. A total of 32 broilers were divided randomly into 4 groups: control, UDS extract-treated, AF-treated and AF+UDS extract-treated. Broilers in control and UDS extract-treated groups were fed on a diet without AF. The AF-treated group and AF+UDS extract-treated groups were treated with an estimated 1 mg total AF/kg feed. The AF+UDS extract groups received in addition 30 ml UDS extract/kg diet for 21 d.

3. The AF-treated group had significantly decreased body weight gain when compared to the other groups.

4. Biochemical analysis showed a small increase in the concentrations of serum aspartate aminotransferase, alanine aminotransferase, gamma glutamyl transpeptidase and lactate dehydrogenase in the AF-treated group compared to that of the control group, whereas concentrations of these enzymes were decreased in the AF+UDS group compared to that of the AF-treated group.

5. Administration of supplementary UDS extract helped restore the AF-induced increase in MDA and reduced the antioxidant system towards normality, particularly in the liver, brain, kidney and heart. Hepatorenal protection by UDS extracts was further supported by the almost normal histology in AF+UDS extract-treated group as compared to the degenerative changes in the AF-treated broilers.

6. It was concluded that UDS extract has a protective hepatorenal effect in broilers affected by aflatoxicosis, probably acting by promoting the antioxidative defence systems.

     

Pathological,biochemical and haematological investigations on the protective effect of α-lipoic acid in experimental aflatoxin toxicosis in chicks

1.?The purpose of this study was to investigate the protective effect of α-lipoic acid (LA) on aflatoxin (AF) toxicosis in chicks.

2.?Groups of 10 Ross PM3 chicks were given, for 21 d, no AF (C), 60 mg/kg/bwt of α-lipoic acid (LA), 150 ppb of aflatoxin (AF1), 150 ppb of aflatoxin plus 60 mg/kg/bwt of α-lipoic acid (AF1 + LA), 300 ppb of aflatoxin (AF2), and 300 ppb of aflatoxin plus 60 mg/kg/bwt of α-lipoic acid (AF2 + LA). Before the animals were killed, blood samples were drawn for haematological analysis, and then tissue samples were collected for histopathological investigation. Immunohistochemical staining was performed against inducible nitric oxide synthase (iNOS) and nitrotyrosine on liver samples. Apoptotic cell death in liver was assessed by in situ TUNEL assay. The malondialdehyde (MDA) and reduced glutathione (GSH) concentrayions in liver and kidney were also determined.

3.?Hydropic degeneration and occasional necrosis, bile duct hyperplasia and periportal fibrosis were observed in the livers of AF-treated groups. The severity of these changes was reduced in LA-supplemented AF groups. Occasionally, thymic cortical atrophy, lymphoid depletion in spleen and bursa of Fabricius, and degeneration in the kidney tubule epitheliums were detected in AF groups. The severity of these degenerative changes was slightly reduced in LA supplemented groups.

4.?There was moderate to strong iNOS and nitrotyrosine immunoreactivity in the livers of AF groups, while decreased immunoreactivity was observed against both antibodies in the LA supplemented groups. Apoptotic cells were numerous in the AF groups, while greatly reduced in LA supplemented groups.

5.?In the liver and kidney of AF-treated groups given 300 ppb of aflatoxin, MDA concentrations were increased as GSH decreased, compared to the control group. LA supplementation of AF-treated birds improved the results compared to the AF only groups, however a statistical difference was observed only in liver tissues between AF2 + LA and AF2 groups. Haematological variables showed no differences among the groups.

6.?In conclusion, supplementation of feed with the antioxidant LA, might ameliorate the degenerative effects caused by aflatoxin due to lipid peroxidation.     

Energy and nitrogen metabolism of diseased chickens: aflatoxicosis.

1. New Hampshire chicks were fed on diets containing 0 (control), 0-7 (A), or 1-1 (B) ppm of aflatoxin B1. In two trials 1-d-old chicks were offered ad libitum the three diets for 14 d. The gaseous exchange of five chickens from each group was measured for 3 or 4 d, the same diets being fed, at 2, 3, 4 and 5 weeks of age in two series of experiments. The controls were fed at the lower intake of the two other groups. Following each series of experiments at the various ages, birds were starved for 24 h and their heat production was re-measured over the next 24 h. 2. Mortality was highest and growth and food conversion poorest where the diet with the highest aflatoxin concentration was fed. Mortality was confined to the first 2 weeks. 3. Performance of birds in the chambers was improved in the second series due to differences in food intake. It also improved with age suggesting some resistance to the toxin. 4. Mean respiratory quotient was 0-97 for fed chickens on diet B. This was significantly different from 0-92 for the two other groups. Similarly, during starvation the RQ was 0-76 compared with 0-73. 5. birds fed on diet B generally grew better, retained more nitrogen and had a better energy balance in the respiration chambers than the other two groups. Metabolisability of dietary energy was less (68.5%) for all groups at 2 to 3 weeks than when older (70%) but availability of ME was the same (71%) for all groups. 6. Heat production (kJ/kg0-75) of starved birds on diet B was significantly lower than the other two groups, while endogenous nitrogen excretion was higher. 7. Water consumption (ml/g food and g/100 g body weight) was greatest for birds on diet B. 8. Although aflatoxin in the diet substantially reduced intake there was no indication that at these reduced levels of intake, nitrogen or energy metabolism were measurably impaired.     

罗曼公母鸡内源氨基酸排泄量的比较研究

试验选取28周龄健康的罗曼公母鸡各16只,分别分为2个处理,每处理8个重复,每个重复1只鸡,分别饲喂2种试验日粮,即无氮日粮(NFD)和NFD+5%酪蛋白,比较分析2种方法测得的公母鸡内源氨基酸排泄量(EAAL)的差异。结果表明:采用NFD法和NFD+5%酪蛋白所得的公母鸡内源氨基酸和总蛋白质的排泄量有所不同。酪蛋白组能够增加内源氮和内源氨基酸的排泄量,NFD+5%酪蛋白法所测得的内源氮和内源氨基酸排泄量更接近试鸡的真实情况。2种测定方法公鸡内源氮和内源氨基酸的排泄量均高于母鸡的结果。     

MYCOTOX and aflatoxicosis in quails

1. This study was to evaluate the toxic effects of aflatoxin (AF) on growth performance of quail, and to determine the preventive efficacy of MYCOTOX (oxicinol, tymol, micronised yeast). 2. One hundred and eighty 1-d-old quail (Coturnix coturnix japonica) of both sexes were weighed and randomly divided into 4 experimental groups each with 5 replicates of 9 birds. 3. There were 4 dietary treatments: (1) control with 0 mg AF/kg diet and 0% MYCOTOX; (2) 0 mg AF/kg diet and 0.5% MYCOTOX; (3) 2.5 mg AF/kg diet and 0% MYCOTOX; (4) 2.5 mg AF/kg diet plus 0.5% MYCOTOX. The chicks were maintained on these treatments to 3 weeks of age. Quail consumed the diets and water ad libitum. 4. Body weight (BW) gains in groups receiving AF alone were the lowest at all periods. Feed intake was lowest in the group consuming the AF diet. The addition of MYCOTOX to the AF diet did not prevent or reduce the toxic effects of AF on feed intake at any time period. Feeding diets containing MYCOTOX alone did not change feed intake significantly. With the exception of the 1 to 7 d period, feed conversion of chicks fed the AF diet was similar to those of the other experimental groups. 5. Bursa of Fabricius weight decreased, whereas the relative weights of liver, kidney and spleen increased in quail consuming diets containing AF and AF plus MYCOTOX. Liver colour was normal in the control and MYCOTOX alone group, but was lighter in groups fed AF. 6. The results indicated that MYCOTOX was not effective in preventing the deleterious effects of AF.     

Efficacy of Montmorillonite Clay (NovaSil PLUS) for Protecting Full-Term Broilers from Aflatoxicosis

Contamination of poultry feeds by aflatoxin is a problem faced by poultry producers at one time or another. Of the several strategies used to reduce the economic effect of aflatoxin-contaminated feeds, the inclusion of selective enterosorbents may be the most practical and cost effective. This study evaluated the effectiveness of montmorillonite clay (MC) supplied as NovaSil PLUS on the performance of full-term commercial type broilers. Eight hundred male commercial broiler chickens (all vaccinated for Marek's disease, Newcastle disease, and bronchitis) were randomly assigned, (20 each) to 40 floor pens and fed 1 of the 4 dietary treatments of industry-type corn-soy broiler diets. Treatments consisted of a control feed, control feed plus 0.5% MC (CMC), a feed containing ˜4,000 ppb aflatoxin (AF), and a feed containing ˜4,000 ppb aflatoxin plus 0.5% MC (AMC). The starter diet was fed for 3 wk, the grower for 2 wk and, the finisher for 1 wk. Selected birds were randomly retained for specific tissue analyses of blood serum; relative liver, spleen, and kidney weights; and histological examination of sampled organs.The combined data showed that birds fed MC as NovaSil PLUS received significant protection against the effects of the aflatoxin for most parameters measured. This level of protection did not totally protect the birds from the effects of feeding extremely high concentrations of aflatoxin, however, as their performance was not as good as that of the control group. To our knowledge this is the first study addressing the protective effects of MC in full-term broilers fed steam-pelleted feeds more nearly approximating commercial production.     

Detecting reproductive system abnormalities of broiler breeder roosters at different ages

The objective of this study was to detect the reasons of rooster's fertility decrease at 50 weeks of age. Therefore, the reproductive system of broiler breeder roosters was laparoscopic, macroscopic and histopathology evaluated, and a comparison of the anatomical aspect with the sperm analysis and birds’ age was realized. Cobb roosters (n = 59) were distributed into two groups (30 and 50 weeks). Evaluations were performed with laparoscopy, macroscopy and histopathology, and seminal quality, blood serum testosterone concentration and weight were also determined. The old roosters presented smaller testicle size, higher intensity epididymal lithiasis and lower testicle sperm production, compared to the young roosters. The use of the endoscope could easily distinguish a normal‐sized testicle than an atrophic one. Four old roosters with severe testicular atrophy did not show spermatogenesis, although three still had sperm in the ejaculate. This would falsely indicate a wrong diagnosis of normal fertility before the testicular atrophy took place. In conclusion, in addition to the weight increase with age, the testicular atrophy and impairment of sperm production seemed to be the main reason to the decrease in the rooster's fertility at 50 weeks of age. Therefore, the use of the laparoscopy as a way to detect the roosters with testicular atrophy before 50 weeks of age and their removal from them flock could be useful as a diagnostic tool to prevent the birds’ fertility loss.     

Changes in the Immunolocalization of Steroidogenic Enzymes and the Androgen Receptor in Raccoon (Procyon lotor) Testes in Association with the Seasons and Spermatogenesis

The raccoon is a seasonal breeder with a mating season in the winter. In a previous study, adult male raccoons exhibited active spermatogenesis with high plasma testosterone concentrations, in the winter mating season. Maintenance of spermatogenesis generally requires high testosterone, which is produced by steroidogenic enzymes. However, even in the summer non-mating season, some males produce spermatozoa actively despite low plasma testosterone concentrations. To identify the factors that regulate testosterone production and contribute to differences in spermatogenetic activity in the summer non-mating season, morphological, histological and endocrinological changes in the testes of wild male raccoons should be known. In this study, to assess changes in the biosynthesis, metabolism and reactivity of testosterone, the localization and immunohistochemical staining intensity of four steroidogenic enzymes (P450scc, P450c17, 3βHSD, P450arom) and the androgen receptor (AR) were investigated using immunohistochemical methods. P450scc and P450c17 were detected in testicular tissue throughout the year. Seasonal changes in testosterone concentration were correlated with 3βHSD expression, suggesting that 3βHSD may be important in regulating the seasonality of testosterone production in raccoon testes. Immunostaining of P450arom and AR was detected in testicular tissues that exhibited active spermatogenesis in the summer, while staining was scarce in aspermatogenic testes. This suggests that spermatogenesis in the raccoon testis might be maintained by some mechanism that regulates P450arom expression in synthesizing estradiol and AR expression in controlling reactivity to testosterone.     

Comparison of prophylactic or therapeutic dietary administration of capsaicin for reduction of Salmonella in broiler chickens

In three experiments the effects of prophylactic or therapeutic dietary inclusion of capsaicin, the pungent component of peppers, were evaluated as a nonantibiotic alternative for reduction of Salmonella in broiler chickens through culture and morphologic assessment of cecal tissue. Expt. 1 evaluated the effects of 0 or 10 ppm purified capsaicin (CAP) in the starter phase (days 1-16) on chicks challenged with Salmonella Enteritidis (SE) on day of age. Therapeutic inclusion of 10 ppm purified CAP increased (P < 0.05) liver/spleen (L/S) and ceca positive results for SE. In Expt. 2, capsaicin oleoresin (CO) was included in the finisher diet (days 30-37) at 0, 5, or 20 ppm with SE challenge on day 31. Inclusion of 5 ppm CO increased ceca positive results for SE, and a linear decrease in cecal lamina propria thickness of SE-challenged birds was observed with increased CO concentration in the diet. Expt. 3 evaluated prophylactic CO treatment at 0, 5, or 20 ppm in starter, grower, and finisher diets for resistance to SE or Salmonella Typhimurium (ST) challenge on day 14 or 29. With challenge on day 14, 5 and 20 ppm prophylactic CO feeding reduced ceca SE positive results by 37% and 26%, respectively, and ST culture rate was reduced similarly with 5 ppm CO. Lamina propria thickness of the ceca increased with 5 ppm CO feeding in SE-challenged birds, whereas a decrease was observed in nonchallenged birds fed 5 ppm CO. Challenge on day 29 of birds fed 20 ppm CO resulted in reduced L/S positive results for SE. Lamina propria thickness decreased with 5 ppm CO and SE or ST challenge compared with nonchallenged birds fed 5 ppm. An increase was observed in ST- or SE-challenged birds fed 20 ppm CO compared with nonchallenged birds fed 20 ppm CO. No differences were observed in mast cell number in either Expt. 2 or 3. These data provide evidence that prophylactic or therapeutic dietary capsaisin differentially affects broiler susceptibility to Salmonella.     

Concentrations of oestradiol and testosterone in peripheral and spermatic venous blood of dogs with unilateral cryptorchidism

Plasma testosterone and oestradiol concentrations were measured in peripheral and spermatic venous blood of 13 dogs with unilateral inguinal cryptorchidism, 9 dogs with unilateral abdominal cryptorchidism, and in a control group of 36 mature normal dogs. The hormone concentrations were similar in the three groups, both in the peripheral and in the spermatic venous blood. The weight of the testes in the control group was correlated with the body weight and there was no significant difference between the weight of the right and the left testes. The weight of the abdominal testes was lower than that of the inguinal testes, and there was no compensatory enlargement of the contralateral scrotal testis. The cryptorchid testes showed little or no histological evidence of spermatogenesis, and spermatogenesis was usually normal in the scrotal testes.     

Comparative Study on Nitrogen Metabolism and the Nitrogen Maintenance Requirement in Lohmann Brown Roosters and Layers

The objective of this study was to investigate the effect of dietary protein level on nitrogen retention and compare nitrogen metabolism in Lohmann Brown adult roosters and layers. The nitrogen maintenance requirement ( Nm ) was determined based on the nitrogen balance. Thirty Lohmann Brown adult roosters and 30 laying hens at 27 weeks of age were randomly divided into five groups of six birds per group. The birds were fed with one of five diets containing 10.46%, 11.77%, 13.79%, 16.77% or 18.29%of crude protein. Nitrogen intake, nitrogen retention and nitrogen retention efficiency were higher in roosters than in laying hens, and the average nitrogen retention rate for groups fed with CP level of 11.77%,13.79%, 16.77% and 18. 29% was improved by 9.14%. The nitrogen maintenance requirement for Lohmann Brown roosters and laying hens at 27 weeks of age were 0.4245 g/d and 0.5059 g/d, respectively,and Nm based on average body weight (BW) and metabolic body weight ( BW0.75 ) was 0.2364 g/kg BW and 0.2739 g/kg BW0.75 for laying hens and 0.2754 g/kg BW and 0.3208 g/kg BW0.75 for roosters, respectively. The regression equations for daily N gain ( NB, protein accretion) vs. daily N intake ( NI )for Lohmann Brown layers and roosters were NB =0.3743NI -0. 1589(R2 =0.79) and NB =0.6228NI -0.3151 (R2 =0.85),respectively. The results of this study indicate that nitrogen intake and nitrogen retention at the same dietary CP level were higher in roosters than in laying hens.     

Influence of selenium on aflatoxin B1 or crotalaria toxicity in turkey poults

This research compared the toxic effects of aflatoxin B1 and monocrotaline, the active principle of Crotalaria spectabilis, and the additive effect between aflatoxin B1 and monocrotaline in turkey poults. It was of interest whether selenium fed at dosage levels of 0.1, 5, or 10 micrograms/g of feed would protect against the toxic effect of aflatoxin and/or monocrotaline, and whether the toxicants would result in detectable residues in poult tissues. A total of 180 healthy 1-day-old male turkey poults was assigned at random to 12 treatment groups (15 birds/group). Body and liver weight losses, and low serum concentrations in total protein (TP), albumin (A), alpha-globulin (alpha G), and beta-globulin (beta G), as well as high values in gamma-globulin (gamma G), were produced in the groups fed crotalaria. Pathologic changes were induced by monocrotaline with no protection afforded by the added selenium. Low values in TP, A, alpha G, and beta G and in body and liver weights were observed in groups given the combination of aflatoxin plus crotalaria. Gross lesions were associated with an additive toxic effect and a lack of protective effect of selenium against this combination. However, higher values in TP, A, alpha G, and beta G, and liver weights in groups fed aflatoxin B1 plus selenium indicated that selenium had a protective effect against aflatoxin toxicity. Residues of aflatoxin B1 and aflatoxin M1 were found in the kidneys of poults fed aflatoxin B1; also, dehydroretronecine (the metabolite of monocrotaline) was detected in livers of poults fed Crotalaria spectabilis seeds.     

The effect of two different feed levels on the development of the reproductive organs in boars.

The aim of the present investigation was to study the development of the reproductive organs in boars fed restrictively and fed ad libitum. A total of 120 boars were purchased by the experimental station at 20 kg live weight. Three groups of 4 litter mates were selected after each of 10 A.I. boars (7 Swedish Landrace and 3 Swedish Yorkshire). The dams were unselected sows from pigletproducing herds. Two boar pigs from each litter were allocated at random among 2 treatment groups. One group ( = N) was fed restrictively and the other group (=A) ad libitum. The boars were slaughtered at 90 kg or at 120 kg live weight. The reproductive organs were removed at slaughter and examined.The ad libitum fed boars were about 2 weeks younger at slaughter than those fed restrictively (16.5 and 13.7 days respectively for the 2 weight classes). The weights of the testes were somewhat higher for ad libitum fed than for restrictively fed boars. Out of 94 examined pairs of testes, epididymides, seminal vesicles and bulbo-urethral glands, the left was heavier than the right in 68%, 62%, 48%, and 36%, respectively. Fewer (4/23) ad libitum fed than restrictively fed boars (9/26) had reached puberty at 90 kg live weight. Age at puberty thus seems to be less variable than body size in boars.     

The Impact of Yeast Culture Residue on the Suppression of Dietary Aflatoxin on the Performance of Broiler Breeder Hens

A study was conducted to examine the effect of yeast culture residue (YCR) on the suppression of aflatoxicosis in broiler breeder hens. One hundred twenty, 35-wk-old, Cobb broiler breeder hens of the same cross were fed diets supplemented with aflatoxin (AF) (0 or 3 mg/kg) and YCR (0 or 2 lb/ton) singly and combined in a 2 × 2 factorial designed experiment. The birds were randomly assigned to pens with 3 replicates of 10 females and 1 male per treatment. Eggs laid by the hens were collected daily, stored at room temperature, and incubated every 7 d for 3 wk. Response variables analyzed were mean percentage of fertility, hatchability, hen-day egg production, egg weight, chick weight at hatch, and embryonic mortality over the 3-wk treatment period. At the end of 3-wk treatment, blood was collected from the hens and analyzed for total protein, globulin, and albumin. Aflatoxin did not negatively affect fertility. However, hen-day egg production (57.6%), percentage of hatchability (67.6%), embryonic mortality (24%), serum total protein, globulin, and albumin were significantly (P < 0.05) affected by AF. Hatch of fertile eggs from the AF-fed hens was significantly lower than the control (67.6 vs. 78.5%). The inclusion of YCR in the AF-treated diet raised the level of hatchability (74.9 vs. 67.6%), egg production (65.83 vs. 57.26%), and lowered embryonic mortality (16.8 vs. 24%). Serum globulin and albumin were lowered in the AF-fed hens but was partially restored with the addition of YCR. The data demonstrated that YCR may enhance the performance of broiler breeder hens that are provided feed contaminated with AF.     

Testosterone concentrations,testes weight and morphology of mule drakes (Muscovy drake X Khaki Campbell)

1. Mule ducks were produced by naturally mating Muscovy drakes and Khaki Campbell ducks. 2. Semen was collected from 6-month-old mule drakes via an artificial vagina. The fluid was clear without any spermatozoa or spermatids. 3. Testes from 27-week-old mule drakes were smaller in size than those of Khaki Campbell drakes but heavier than Muscovy males of the same age. Histological sections of these testes revealed that spermatogenesis was not complete. 4. Testosterone concentration in the mule drakes was higher than in Muscovy males but similar to Khaki Campbell drakes. 5. Mule drakes have strong sexual drives as a result of high concentrations of testosterone, but, because spermatogenesis is incomplete, their semen had no sperm.     

Characterization of the toxicity of the mycotoxins aflatoxin, ochratoxin, and T-2 toxin in game birds. II. Ringneck pheasant.

Ringneck pheasants were fed diets containing 1.25, 2.5, or 5 ppm aflatoxin; 1, 2, or 4 ppm ochratoxin A (OA); or 4, 8, or 16 ppm T-2 toxin. Severe toxin-induced mortality was seen during the first to third weeks with 2.50 and 5.00 ppm aflatoxin (92.5% and 97.5%, respectively), compared with the mortality in control pheasants fed no toxin (0%). Slight mortality (less than or equal to 5%) was seen with OA and T-2 toxin. Body weights were significantly decreased by the lowest level (1.25 ppm) of aflatoxin by 2 weeks of age, by the two highest levels of aflatoxin by 1 week of age, and by 16 ppm T-2 toxin by 1 week of age. The feed-conversion ratio was increased by 2.50 and 5.00 ppm aflatoxin compared with the feed-conversion ratio in controls, although high mortality may have influenced the results. Aflatoxin had no effect on liver weight, but OA increased kidney weight in 3-week-old pheasants. Mouth lesions were seen in some of the pheasants fed T-2 toxin.     

Effect of aflatoxin B1 on the efficacy of turkey herpesvirus vaccine against Marek's disease

The effect of feeding aflatoxin B1 (AFB1) (0.5 ppm) was studied in young chicks. The frequency and the severity of gross and microscopic lesions of Marek's disease were significantly higher in those birds which had been vaccinated with turkey herpesvirus (HVI) and birds challenged with Marek's disease virus which had been given AFB1 in the feed than in those given normal feed. The protective efficacy of HVT vaccine, as judged on the basis of gross and histopathological lesions, was 86.1 and 77.3 per cent in normally fed birds in comparison to 37.6 and 8 per cent in AFB1 fed birds.     

Fluctuation in the concentration of sex steroids and aflatoxin B1 in the seminal plasma of boars and its relation to sperm production

The concentration of testosterone, 17-beta oestradiol and aflatoxin B1 were studied in the semen plasma of 21 boars of four breeds for the period of twelve months. The following spermiological parameters were investigated: semen volume, sperm concentration, percentage of abnormal spermatozoa, and survival of spermatozoa. The fertilizing capacity of ejaculates was evaluated according to the conception rate of sows and gilts after the first insemination, according to the average number of piglets per litter and average number of live-born piglets per litter. The highest aflatoxin B1 residues in sperm were recorded in March to May and were related with aflatoxin concentration in feed ration. The group of boars with fertility disorders had more aflatoxin in their sperm (up to 100 pmol . l-1), lower sperm concentration, lower survival of spermatozoa, and a larger proportion of abnormal spermatozoa. The year season had a significant influence on the concentration of the hormones. The highest average value of testosterone (10.2 +/- 1.28 nmol) was obtained in autumn and lower values were recorded in winter. The changes in 17-beta estradiol concentration were similar to the changes in testosterone content, with the maximum value in November (0.249 nmol X 1(-1]. The boars with reproduction disorders had a significantly lower concentration of 17-beta oestradiol. Significant correlations were found between the concentration of the hormones, semen volume, and sperm concentration. 17-beta oestradiol also had a significant positive correlation to abnormal spermatozoa and to the activity of aspartate aminotransferase.     

Short-term exposure to subacute doses of aflatoxin-induced depressed mitogen responses in young mallard ducks

Mallard ducklings were fed diets containing corn naturally contaminated with mixed aflatoxins, purified T-2 toxin, or no detectable mycotoxin in two trials. The aflatoxin level used was 12 ppb in the first trial and 33 ppb in the second. T-2 was added at 2 ppm in both trials. No pathology was associated with the aflatoxin used in this study, and T-2--induced lesions were described in a previous publication. The weights of primary (thymus and bursa of Fabricius) and secondary (spleen) lymphoid organs were significantly reduced in the T-2--treated birds. The total number of viable cells recovered from the thymus was significantly reduced in aflatoxin-treated birds. The numbers of viable cells recovered from thymus, bursa of Fabricius, and spleen were all significantly reduced after treatment with T-2. In each trial, significantly lower mitogenic responses were seen to pokeweed mitogen and concanavalin A in birds fed aflatoxin or T-2, representing reduction in both B-cell and T-cell mitogenesis. Birds fed aflatoxin also had significantly reduced Escherichia coli O55 lipopolysaccharide-induced mitogenic responses. These studies indicate that subacute oral exposure to aflatoxin caused a loss of normal lymphocyte reactivity in mallard ducklings. This finding supports the hypothesis that waterfowl that ingest even small quantities of mycotoxin-contaminated waste grain are likely to be more susceptible to bacterial or viral infections.