Low concentrations of zearalenone in diets of mature gilts

Four groups of sixteen gilts were each individually fed diets containing 0, 3, 6 or 9 ppm pure zearalenone starting the day after they exhibited puberal estrus. They were artificially inseminated twice at subsequent heat periods. Fifteen of the 30 gilts not exhibiting estrus within 80 d of the start of the experiment were slaughtered and their reproductive tracts examined. The remaining 15 gilts that did not return to estrus were fed the control diet after 80 d to determine the effect on return to estrus. Eighty-eight percent of the gilts fed 6 or 9 ppm zearalenone became pseudopregnant as confirmed by plasma progesterone levels and(or) examination of their reproductive tracts. However, three animals fed the two higher levels of zearalenone conceived and farrowed. No conclusions can be made regarding the effect of zearalenone on litter size due to the relatively few numbers of gilts fed the higher levels of zearalenone that farrowed. Gilts fed diets containing 6 or 9 ppm zearalenone returned to estrus spontaneously (n = 7) or following injection of cloprostenol (n = 8) approximately 45 d after the removal of zearalenone from their diet.     

Natural contamination of dietary rice straw with zearalenone and urinary zearalenone concentrations in a cattle herd

The present study was conducted to 1) identify the natural source of feed contamination by zearalenone (ZEN), which was suspected to have caused persistently increased urinary ZEN concentrations in one of our experimental cattle herds, and 2) evaluate the effects of intervention against this source of contamination. As an experimental model, a fattening Japanese Black cattle herd showing persistently increased urinary ZEN concentrations was identified. Urinary ZEN concentrations of cows fed with new rice straw (experimental group, n = 6) vs. cows that continued to feed on the old rice straw (control group, n = 4) were measured at the start (d 1) and at 2 wk (d 14) after the onset of feeding with straw. In addition, the ZEN concentration in feed and water samples was measured by using both the ELISA and HPLC methods. Furthermore, isolation and identification of fungi from rice straw and concentrate feed samples were performed. The urinary ZEN concentration [ZEN (pg/mL)/creatinine (mg/mL) = pg/mg of creatinine] of cows fed with new rice straw was significantly (P < 0.05) less (843 pg/mg of creatinine) than that of cows fed with old rice straw (15,951 pg/mg of creatinine). On both d 1 and 14, the ZEN concentrations of old rice straw were greater than those of new rice straw. In addition, fungal colonies were observed in the culture media that was obtained from the old rice straw suspected of ZEN contamination, but not in the culture media from new rice straw or other feed samples. In conclusion, our field trials clearly indicate that the rice straw fed to the cows was naturally contaminated with ZEN, and that the monitoring of urinary ZEN concentrations could prove to be a useful tool for detecting the exposure of cattle to ZEN contamination at the farm level.     

日粮蛋氨酸含量对岭南黄鸡前期生产性能的影响

采用单因子试验设计，将400只1日龄岭南黄鸡母雏随机分成5组，研究了5个日粮蛋氨酸水平（0．28％、0．40％、0．50％、0．60％、0．70％）对岭南黄鸡前期（0－4周）生产性能的影响。结果表明，日粮蛋氨酸水平为0．50％、0．60％、0．70％组的增重、耗料量和料肉比等指标间差异均不显著（P＞0．05），但显著高于蛋氨酸水平为0．40％组（P＜0．05）和0．28％组（P＜0．01）。因此，建议岭南黄鸡前期（0－4周）日粮蛋氨酸水平以0．50％为宜。     

Effect of castration on plasma luteinizing hormone concentrations in prepubertal boars

Mean concentrations and the occurrence of pulsatile release of luteinizing hormone (LH) were determined in 14-wk-old crossbred boars (50.5 +/- 1.5 kg) after bilateral or unilateral castration at 10 wk of age. Blood was collected at 10-min intervals for 5 h. Then gonadotropin releasing hormone (GnRH; 40 micrograms) was given and sampling was continued at 5-min intervals for 1 h. Compared with intact boars, bilateral castration increased (P less than .001) mean LH (982 +/- 56 vs 389 +/- 56 pg/ml), pulsatile releases of LH (7.0 +/- .6 vs 2.0 +/- .6 pulses/5 h) and LH pulse amplitude (617 +/- 29 vs 360 +/- 58 pg/ml). Unilaterally castrated boars did not differ from intact boars in any of the above measures of LH secretion. Testis weight increased more between 10 and 14 wk of age in the unilateral castrates than in the intact boars (432 +/- 42 vs 245 +/- 34%; P less than .05). Thus, compensatory hypertrophy occurred within 4 wk of castration. Plasma testosterone was lower for bilateral castrates than for intact animals (.1 +/- .8 vs 3.6 +/- .9 ng/ml; P less than .05) while unilateral castrates (3.8 +/- 1.0 ng/ml) and intact boars did not differ. Plasma estradiol concentrations in bilateral and unilateral castrates were not different from levels found in intact boars (1.8 +/- 1.8, 8.8 +/- 2.1 and 6.0 +/- 1.8 pg/ml, respectively).(ABSTRACT TRUNCATED AT 250 WORDS)     

Blood vitamin concentrations in privately owned dogs fed non-standardized commercial diets and after intake of diets with specified vitamin concentrations

The objective was to investigate in a survey study the blood vitamin concentrations in healthy dogs fed non-specified commercial complete diets and in an intervention study to determine the effects of defined dietary vitamin intakes on blood vitamin levels and hair and skin condition. Sixty-four privately owned dogs, aged from 1 to 8 years, without history of skin or coat problems were included. All animals were fed commercial complete diets with uncertain vitamin concentrations before enrolment. The animals were assigned, according to weight and gender, to four groups with graded vitamin intakes. The blood vitamin levels and skin and coat quality of the dogs were investigated at days 0 and day 122. Coat and hair condition was not influenced by the experimental diets. The retinol concentrations were reduced at the end of the experiment compared with the baseline levels, retinyl esters were not influenced. 25-Hydroxycholecalciferol decreased in all groups, alpha-tocopherol was constant or tended to decrease. Ascorbic acid, thiamine pyrophosphate and riboflavin concentrations were not affected by treatment, flavin adenine dinucleotide and pyridoxal-5'-phosphate were partially reduced on day 122. Cobalamin, pantothenate and biotin concentrations increased with higher dietary intakes, folate levels in tendency. In conclusion, this study gives a survey of blood vitamin concentrations in healthy dogs and provides a data base for the evaluation of the vitamin status in health and disease.     

Changes in hormone and metabolite concentrations in plasma of steers during a prolonged fast

Two Brown Swiss and two Holstein steers, average weight of 226 kg, were fasted 8 d. Two days before the fast, jugular vein catheters were installed. Blood samples were collected every 15 min from 0800 to 1400 h on d 0, 2, 5 and 8 of fasting. Plasma from each sample was analyzed for concentrations of growth hormone, and from selected samples for insulin, glucagon, glucose, beta-hydroxybutyrate, free fatty acids, urea N and glycerol. Both growth hormone and insulin concentrations decreased by d 2 of the fast and remained at that concentration. Glucagon, however, remained constant. From d 0 to 2, concentrations of beta-hydroxybutyrate, free fatty acids and glycerol increased but then changed little for d 5 and 8. From d 0 to 2, glucose decreased and urea N increased. In contrast to the other metabolites, glucose and urea N concentrations stabilized between 3 and 5 d of fasting. The ratio of growth hormone to insulin decreased threefold and the ratio of glucagon to insulin decreased fivefold from d 0 to 2; both ratios remained constant during the rest of the fast. The data indicate that fasting cattle adapt by decreasing concentrations in plasma of growth hormone and insulin but not glucagon. These endocrine changes, therefore, seem responsible for greater rates of free fatty acid mobilization and glucose sparing during an energy deficit.     

Variation of the serum testosterone level in boars during 24 hours and during a period of several days]

Seven sexually mature boars were studied in two-hour intervals for 8 to 32 hours, as to the variation of testosterone levels in the blood plasma. Blood samples were obtained by means of a cannula inserted in the v. cava cranialis. The hormone level under study showed marked fluctuation. The coefficient of variation of testosterone concentration ranged from 12.7% to 35.2% in the individual animals and for the whole part of the study it was 33.0%. It appeared impossible to derive seriously any regular periodicity of testosterone concentration in boar blood in the 24-hour period from the analysis of the variation of the levels of the hormone in individual animals during the period under study. Further, the study revealed a marked fluctuation of testosterone levels in the blood plasma of twelve sexually mature boars in the course of several days' study. The coefficient of variation of testosterone concentration in individual animals ranged from 18.1% to 106.5%, reaching 77.0% for the whole part of study. The analysis of variance showed statistically significant differences of hormonal levels in individual boars in which the fluctuation of testosterone was studied in the 8- to 32-hour period as well as in several days' period. This proved the role of the animals' individuality in determining the concentration of testosterone in their blood. The discussion concerns the importance of these findings for the evaluation of the role of basal testosterone levels in the blood in classifying the incretion function of the gonads and in the diagnosis of incretion hypogonadism of boars.     

Calorimetric measurements on chickens given diets with a range of energy concentrations

Eight diets with metabolisable energy (ME) concentrations ranging from 9–1 to 15–3 MJ/kg were given to groups of five chickens kept in respiration calorimeters for 3 to 4 d. Availability of ME ranged from 57% to 79%. One diet differed from the others, but for those groups of chickens on the other seven diets availability of ME was 80% when energy balance was negative and only 60% when positive.

Protein synthesis appeared to continue when chickens were in negative energy balance and fat was frequently catabolised when birds were in positive energy balance, apparently to support protein synthesis.     

Serum chlortetracycline concentrations in parrots fed medicated seed diets

Various seed diets containing chlortetracycline were fed to large and small parrots to evaluate serum chlortetracycline concentrations. The substitution of dehulled sunflower seed for whole sunflower in the seed mix may have resulted in higher chlortetracycline concentrations in cockatoos and parrots. The serum chlortetracycline concentration achieved for all diets was less than the goal of 1 μg/mL, but the concentrations attained may be useful for therapy.     

Changes in the concentrations of fumonisin,deoxynivalenol and zearalenone in corn silage during ensilage

We assessed the production of the mycotoxins fumonisin, deoxynivalenol and zearalenone during the ensiling of corn. Corn was harvested at yellow‐ripe or full‐ripe stage and separated into the stem and leaf parts and the ear parts, including bracts. Each material was ensiled under five conditions: (1) no fungus added, anaerobic conditions; (2) no fungus added, aerobic conditions; (3) mycotoxin‐producing fungus added, anaerobic conditions; (4) mycotoxin‐producing fungus added, aerobic conditions; and (5) mycotoxin‐producing fungus added to autoclaved material, aerobic conditions. After 40 days of ensilage, we analyzed the silage fermentative quality and mycotoxin concentration. The fermentative quality of all materials was good in treatments (1) and (3), because the pH < 4 increased the lactic acid content preventing mycotoxin levels from increasing. In treatments (2) and (4), fermentative quality of all materials was poor, and mycotoxin levels were slightly increased. In treatment (5), fermentative quality was poor, and mycotoxin levels were increased remarkably. These results indicate that mycotoxins are not produced under anaerobic conditions and are hardly produced under aerobic condition during the ensiling of corn. Our findings suggest that almost all mycotoxins in corn silage are produced pre‐harvest.     

Optimizing xanthophyll concentrations in diets to obtain well-pigmented yolks

The color of the egg yolk depends on the absorption and deposition of the carotenoids in the hen diet and represents a visual characteristic of great effect on the product acceptance. Corn is commonly used as an energy value ingredient for the hen diet formulations, but its pigmenting potential should also be considered for egg yolk color. The objective of this research was to optimize the proportions between yellow and red carotenoids in corn-based rations to provide the maximization of a yolk's color. For our study, Dekalb laying hens were individually allotted in cages to receive the 15 experimental diets defined by means of a central composite design in which the variables were the yellow xanthoplhylls from the diets (yellow corn + corn gluten meal), the yellow supplementary xanthoplhylls (lutein + zeaxanthin), and the red supplementary xanthoplhylls (cantaxanthin) at 3 concentrations each. Production traits were not influenced by treatments. Seven distinct colors were identified with the yolk color fan; the preferred one (9) was provided by the highest yellow pigment concentrations with no red pigments, whereas the most rejected one (14) was provided by the highest concentration of red pigment. The objective color was derived from the interaction between yellow and red xanthophylls, with an important effect of red supplementary xanthophylls on redness. Using response surface analyses, 0.5 mg/hen per day of red pigments and 1.5 mg/hen per day of total yellow pigments were enough to reach maximum redness (color index 14), whereas 2.0 mg/hen per day of total yellow xanthophylls were enough to reach local consumer preference (color index 9).     

Concentrations of oestrogens in blood plasma and seminal plasma of boars during the postpuberal period

Concentrations of oestrogens in the blood plasma and seminal plasma of mature boars are high. However, little is known about their concentrations after reaching sexual maturity. The aim of this study was to determine the concentration of oestrogens in blood plasma and seminal plasma of boars during the postpuberal period. Free and conjugated oestrone and oestradiol-17beta were determined by radioimmunoassay in blood from the testicular vein and artery, and peripheral circulation as well as in seminal plasma collected from 18 Polish Landrace boars. The animals were divided into three groups (n = 6) according to age (8, 12 and 16 months, respectively). Oestrone was predominant free and conjugated oestrogen. The highest values of oestrogens were measured in the testicular vein (p < or = 0.05). The concentrations of oestrogens in seminal plasma did not differ from those found in the peripheral circulation. An age-dependent increase in levels of all four oestrogens (p < or = 0.05) was observed. This can be associated with biochemical maturation of the reproductive system during the postpuberal period.     

Relationships of testicular iron and ferritin concentrations with testicular weight and sperm production in boars

The inverse relationship of testicular size and circulating follicle-stimulating hormone (FSH) concentrations has been documented, and accompanying this relationship is the change in color of the parenchymal tissue of the testes. Large testes (300 to 400 g) are pink to light red and small testes (100 g) are dark maroon with color gradations for weights in between. It was hypothesized that this color most likely represented an iron protein. Chromatographic analysis of testicular tissue indicated that the Fe was associated primarily with ferritin, and immunohistochemistry showed that Leydig cells were the primary location of ferritin storage within the testes. Concentrations of Fe and ferritin were higher in small testes and decreased as testes weight increased (P < 0.05). As testicular Fe concentrations increased, daily sperm production (DSP) and total DSP declined (P < 0.05). Genotyping six generations of Meishan x White composite boars (n = 288) for a quantitative trait locus that is indicative of elevated FSH and small testes in boars indicated that the Meishan genotype had elevated testicular iron concentrations and darker color in conjunction with reduced total DSP (P < 0.01). It is not thought the elevated iron concentrations affect testicular weights but are probably a result of elevated FSH and FSH inducement of Fe transport. The storage of Fe in Leydig cells may provide a reservoir of Fe for easy access by Sertoli and germ cells, but still provide a degree of protection to germ cells from ionic iron.     

Circadian variations in salivary chromogranin a concentrations during a 24-hour period in dogs

The purpose of this study was to determine if salivary chromogranin a secretion in dogs exhibits a circadian rhythm. Saliva sampling was performed during three different sessions occurring in three nonconsecutive 24-h periods. Sixteen healthy adult beagle dogs (8 males and 8 females) were moved to a sampling room and housed individually in cages. Saliva samples were obtained every 4 h from 12:00 p.m. to 12:00 p.m. the following day. In the interest of habituation, saliva was obtained hourly from each dog 3 h before the experiment was started. Salivary chromogranin A concentrations were measured using an enzyme-linked immunosorbent assay. No circadian rhythm was detected for salivary chromogranin A secretion, and no differences in salivary chromogranin A concentrations measured every 4 h were demonstrated during the 24-h cycle in dogs.     

Occurrence of the fusariotoxins deoxynivalenol and zearalenone in Austrian feedstuff in the period from 1995 to 1999

3970 feed samples were analysed for the fusariumtoxins deoxynivalenol and zearalenone. 979 (24.6%) of the submitted feed samples from farms with case history (swine herds: decreased feed intake and daily weight gain, vomiting, cannibalism, impaired fertility, small litter size, weakness of newborn piglets, prolonged oestrus of sows; cattle: persistence of follicular ovarian cysts, enteritis, decreased slaughter weight, feed refusal). 74% of the samples contained cereal and corn ingredients respectively or were complete diet samples from swine herds. Based on economic losses the fusariumtoxin deoxynivalenol is most important in Austrian husbandry and particularly found in maize, cornsilage, wheat and oat.     

Genetic parameters for testosterone production in boars

Data were collected in 1982 through 1989 from 66 sires and 358 Duroc boars. Testosterone production was measured from peripheral blood samples before (PRE) and after (POST) GnRH challenge. Additionally, data were collected on testes length at 168 d (TL168), testes width at 168 d (TW168), testes volume at 168 d (TVOL), birth weight (BWT), average daily gain (ADG), days to 104 kg (DAYS104), and backfat adjusted to 104 kg (FAT). Overall means for these traits were 24.6 ng.ml-1.h-1, 75.7 ng.ml-1.h-1, 12.3 cm, 11.6 cm, 422.0 cm3, 1.5 kg, .5 kg, 189.3 d, and 18.5 mm, respectively. Son-sire regressions were used to calculate genetic parameters. Heritabilities for PRE, POST, TL168, TW168, TVOL, BWT, ADG, DAYS104, and FAT were .37, .26, .33, .34, .33, .21, .42, .35, and 0, respectively. Moderately favorable genetic correlations were obtained for PRE and POST with growth measurements. Large positive genetic correlations were present for both PRE and POST with TL168, TW168, and TVOL, and testes measurements had large positive genetic correlations with growth traits. Selection for testes size or testosterone production should be equally effective. However, it seems that selection for testes size would result in larger changes in measures of growth than selection for testosterone. This study suggests that testes measurements are good predictors of both basal and challenge testosterone levels. Selection for increased testis size or increased testosterone levels would be expected to enhance growth.     

Low ambient temperature elevates plasma triiodothyronine concentrations while reducing digesta mean retention time and methane yield in sheep

Ruminant methane yield (MY) is positively correlated with mean retention time (MRT) of digesta. The hormone triiodothyronine (T₃), which is negatively correlated with ambient temperature, is known to influence MRT. It was hypothesised that exposing sheep to low ambient temperatures would increase plasma T₃ concentration and decrease MRT of digesta within the rumen of sheep, resulting in a reduction of MY. To test this hypothesis, six Merino sheep were exposed to two different ambient temperatures (cold treatment, 9 ± 1 °C; warm control 26 ± 1 °C). The effects on MY, digesta MRT, plasma T₃ concentration, CO₂ production, DM intake, DM digestibility, change in body weight (BW), rumen volatile fatty acid (VFA) concentrations, estimated microbial protein output, protozoa abundance, wool growth, water intake, urine output and rectal temperature were studied. Cold treatment resulted in a reduction in MY (p < 0.01); digesta MRT in rumen (p < 0.01), hindgut (p = 0.01) and total digestive tract (p < 0.01); protozoa abundance (p < 0.05); and water intake (p < 0.001). Exposure to cold temperature increased plasma T₃ concentration (p < 0.05), CO₂ production (p = 0.01), total VFA concentrations (p = 0.03) and estimated microbial output from the rumen (p = 0.03). The rate of wool growth increased (p < 0.01) due to cold treatment, but DM intake, DM digestibility and BW change were not affected. The results suggest that exposure of sheep to cold ambient temperatures reduces digesta retention time in the gastrointestinal tract, leading to a reduction in enteric methane yield. Further research is warranted to determine whether T₃ could be used as an indirect selection tool for genetic selection of low enteric methane‐producing ruminants.     

Effects of chronic gonadotropin-releasing hormone agonist treatment on serum luteinizing hormone and testosterone concentrations in boars.

Mature boars were subjected to chronic treatment with a gonadotropin-releasing hormone (GnRH) agonist, goserelin (D-Ser[But]6, Azgly-NH210), and serum luteinizing hormone (LH) and testosterone concentrations were measured. Ten sexually mature boars were randomly assigned to treatment (n = 5) or control (n = 5) groups. On day 0, boars were implanted sc (day 0) with 2 GnRH agonist implants (1 mg of GnRH/implant) or sham implants. Blood samples were collected at 12-hour intervals on days -2 and -1, at 6-hour intervals on days 0 through 4, and at 12-hour intervals on days 5 through 8. In addition, blood samples were collected at 15-minute intervals for 6 hours on days -1, 0, 4, and 8. Serum testosterone and LH concentrations were determined by radioimmunoassay. Maximal LH (7 +/- 1 ng/ml) and testosterone (26 +/- 3 ng/ml) concentrations were observed at 5 and 18 hours, respectively, after GnRH agonist treatment. Subsequently, LH and testosterone concentrations decreased to pretreatment values (0.3 +/- 0.1 ng/ml and 1.8 +/- 0.4 ng/ml, respectively) by 24 and 48 hours, respectively, after GnRH agonist implantation. Few differences in the characteristics of pulsatile LH release were observed between the groups. Testosterone and LH concentrations in samples collected at 6- and 12-hour intervals and pulsatile LH release did not change after sham treatment of control boars. Whereas previous reports indicated that chronic GnRH administration suppressed serum LH and testosterone concentrations in rams, rats, and dogs, our results indicate that chronic GnRH agonist treatment induced transitory increases, without subsequent suppression, in LH and testosterone concentrations in mature boars.