Onset of puberty in CD-1 mouse pups exposed prenatally through weaning to endophyte-infected tall fescue seed

This study was undertaken to investigate the effects of feeding endophyte - infected (Acremonium coenophialum ) tall fescue seed to CD-1 mouse dams (P(1)) during gestation and lactation, and on the subsequent growth and sexual maturity (onset of puberty) of their male and female offspring (F(1)). Forty-eight 21 d old pups (24 male and 24 female F(1) mice) were weaned from dams fed one of two diets containing 50% rodent chow (w/w) and 50% KY-31 tall fescue (Festuca arundinacea ) seed. The seed in Diet 1 was noninfected, while the seed in Diet 2 was 80% endophyte-infected. At weaning (21 d), the F(1) pups were fed rodent chow, ad libitum throughout the remaining experimental period. At 24 d, they were paired with sexually mature non-treated virgin CD-1 mice (fed 100% rodent chow) for one parturition cycle. Male F(1) mice were sacrificed at 84 d to determine testicular development. The age at the birth of the first litter for Diet 2 F(1) male (76.8 +/- 2.2 d) and female (58.4 +/- 2.1 d) was significantly greater (P<0.05) than the age at parturition for Diet 1 male and female F(1) test mice (64.1 +/- 1.8 and 51.9 +/- 1.2 d, respectively). At parturition, the female F(1) mice showed no significant differences (P>0.05) in either mean parturition weight or number of F(2) pups born per litter. However, total F(2) litter wight (11.38 +/- 1.14 g) and mean weight per F(2) pup (1.40 +/- 0.04 g) for Diet 2 female F(1) mice litters were lower (P<0.05) when compared with Diet 1 females (14.53 +/- 0.57 g and 1.66 +/- 0.02 g, respectively). No significant differences were observed between the two male F(1) treatment groups, for total F(2) litter weight or the number of pups born per F(2) litter. Although Diet 2 F(1) males weighed significantly less (P<0.05) at weaning and at pairing, final body weights at sacrifice (84 d) were not different (P>0.05) from the Diet 1 males.     

Effects of feeding endophyte-infected tall fescue seed on the reproductive performance in male and female CD-1 mice by combination crosses

The present study was undertaken to assess the effects of endophyte-infected Acremonium coenophialum tall fescue (KY 31) seed (80% infected) on the reproductive performance of male and female CD-1 mice by combination crosses. Forty-eight male and 48 female 30-d-old mice were randomly allocated to two diet treatments. Twenty-four males and 24 females were fed Diet 1, consisting of 50% non-infected fescue and 50% mouse chow; the remaining animals were fed Diet 2, containing 50% infected fescue. At the end of 50 d, the animals were paired in groups (n = 12) as follows: 1) Diet 1 males and females; 2) Diet 2 males and Diet 1 females; 3) Diet 1 males and Diet 2 females; and 4) Diet 2 males and females. The pairs were maintained on the diets of their female partners and were allowed to cohabitate for 96 h. After this period the males were removed and the females were carried to term. Pregnancy rates among the four treatment groups were 100, 83.3, 75.0 and 54.5%, respectively. Similarly, the average number of pups born per litter among the four groups were 11.5, 8.0, 9.7, and 7.5, respectively. Also, the weights (grams) of pups born per litter were 17.5, 12.6, 12.4, and 9.8, respectively. The results point out that the reproductive capacity of both male and female mice are affected (P < 0.05) by the ingestion of endophyte-infected fescue seeds. Such negative effects were more severe in the female than the male (P < 0.05).     

Lactation in mice fed endophyte-infected tall fescue seed

This study was conducted to assess the effects of endophyte-infected Acremonium coenophialum tall fescue (KY-31) seed (80% infected) on lactation in CD-1 dams and suckling performance of pups as measured by pup survival and growth rates. Twenty-four pairs of mature CD-1 mice were randomly allocated to four dietary treatments: 1) 100% mouse chow ad libitum; 2) 40% endophyte-infected tall fescue seed and 60% mouse chow (w/w); 3) reduced intake (100% chow), adjusted daily to the intake level of Treatment 2; and 4) 60% infected tall fescue seed and 40% chow. The mice were preconditioned on their respective diets for 100 d prior to 96 h of cohabitation between pairs of males and females. At parturition the litters were removed, and each dam was given a litter of six pups of equal weight, size and sex ratio to suckle for 15 days. All pups given to all the dams were born to other mice that were not part of the study and had not been exposed to endophyte-containing diets. Dams and litter weights were measured daily for 15 consecutive days. The combined body weight measurements of litters from dams fed the tall fescue containing diets (Treatments 2 and 4) were significantly lower (2.07 +/- 0.41 g/d) than that of litters from dams fed the chow containing diets (Treatments 1 and 3) during the suckling trial (P<0.05). Similarly, nine of ten (90%) dams fed the chow containing diets maintained five or more pups (5.5 +/- 0.2) throughout the study as compared to five of nine (55.6%) dams fed the tall fescue containing diets that maintained less than five pups (4.5 +/- 0.2).     

Effects of feeding endophyte-infected tall fescue seed on reproductive performance in male CD-1 mice by competitive breeding

The objective of this study was to assess the effects of endophyte-infected tall fescue (KY-31) seed (80% infected, containing Acremonium coenophialum ) on the reproductive performance of male CD-1 mice measured by competitive breeding. Sixteen mature CD-1 male mice were randomly allocated to one of two dietary treatments containing 50% mouse chow and either 1) 50% noninfected tall fescue seed, restricted to the daily feed intake of dietary treatment 2, or 2) 50% infected tall fescue seed (w/w) fed ad libitum. Mice were preconditioned on their respective diets for 50 d prior to 96 h of cohabitation with 10 mature CD-1 females. Following removal of males, the females were carried to full term. Males were sacrificed, and testicular, epididymal weights, sperm motility and progressive sperm motility were assessed. The results showed no differences (P>0.05) in average daily weight gain (ADG) and body weight changes during the course of the experiment between the two dietary treatments. There were significant reductions (P<0.05) in total testes weight (0.238 vs 0.214 g), epididymal weight (0.087 vs 0.073 g), sperm motility (82.5 vs 58.7%), and progressive motility (3.7 vs 2.6; scale 0 to 4) between dietary treatments 1 and 2, respectively. Similarly, significant differences in pregnancy rates were 53.8 and 45.0%, and the average numbers of pups born per litter were 10.67 and 9.84, respectively. These data suggest that 50% endophyte-infected fescue seed in the diet of male CD-1 mice can affect their reproductive capacity by influencing the testicular-epididymal weights, and subsequently, the quality of spermatozoa and overall fecundity.     

Effect of feeding fungal endophyte (Acremonium coenophialum )-infected tall fescue seed on reproductive performance in CD-1 mice through continuous breeding

This study was designed to assess the effect of endophyte-infected (Acremonium coenophialum ) tall fescue (KY-31) seed (80% infected) on reproductive performance in CD-1 mice by continuous breeding. Twenty-four pairs of 70-d-old CD-1 mice were randomly allocated to four diets: 1) mouse chow ad libitum; 2) 40% infected fescue seed and 60% chow (w/w); 3) reduced intake (100% chow) similar to the intake, adjusted daily, in Diet 2; and 4) 60% infected fescue seed and 40% chow. Males and females were randomly paired (six pairs/treatment) and placed on the above diets. The mice were fed the corresponding diets for 80 d, although the pairs were separated on Day 60 (prior to the birth of the 3rd litter) and the females were monitored for one additional gestation period (20 d). The pregnancy data (litters produced) among the four treatments were 100.0 (18), 77.8 (14), 100.0 (18) and 80.0% (12) respectively. Similarly, the average number of pups born per litter among the four treatments was 11.8, 9.3, 10.1, and 9.8. When the chow treatment (1 and 3) and the fescue treatments (2 and 4) were pooled and compared, the percent pregnancy was 100.0 (n = 36) and 78.8 (n = 26), and the pups born per litter (means +/- SEM) were 11.0 +/- 0.5 and 9.5 +/- 0.6, respectively. Also the intervals between the three litters born during the 60-d cohabitation period were 21.6 +/- 1.1 and 24.5 +/- 0.9 d for the chow and fescue treatments, respectively. The results point out that 40 and 60% infected fescue seed in the diet of mice does influence (P < 0.05) their reproductive capacity as measured by percent pregnancy and litter size.     

The effect of feeding tall fescue seed infected by Acremonium coenophialum on pregnancy and parturition in female rats

1. Female Sprague-Dawley rats (Rattus norvegicus) were randomly assigned to various dietary treatments containing: (1) 100% Purina rodent chow, ad libitum; (2) same as 1, but restricted to daily intake of 7; (3) 50% rodent chow (w/w) and 50% endophyte-free tall fescue (Festuca arundinacea) seed; (4) same as 3, but restricted to intake of 5; (5) 50% rodent chow, 25% endophyte-free tall fescue seed and 25% endophyte-infected (Acremonium coenophialum) tall fescue seed; (6) 50% rodent chow, 12.5% endophyte-free and 37.5% endophyte-infected tall fescue seed; and (7) 50% rodent chow and 50% endophyte infected tall fescue seed. 2. Average daily feed intakes and average daily weight gains decreased with higher levels of endophyte infected seed. 3. Frequency of litter production was affected by all endophyte-infected containing diets. 4. Conception was reduced only in dietary treatment (7). 5. Litter weights, number of pups per litter and weight per pup were proportionally reduced as higher levels of infected seed were incorporated in the ingested diets.     

Fertilization rates and embryonic development in CD-1 mice fed fungal endophyte-infected tall fescue seed

The objective of this study was to assess the effects of endophyte-infected tall fescue (KY-31) seed (80% infected, containing Acremonium coenophialum ) on the fertilization rates and embryonic development of CD-1 mice. Twenty-four pairs of mature CD-1 mice were randomly allocated to two dietary treatments containing 40% mouse chow and 1) 60% noninfected tall fescue seed or 2) 60% infected tall fescue seed (w/w). The mice were preconditioned on their respective diets for 60 d prior to 96 h of cohabitation between pairs of males and females. Following the removal of the males, equal numbers of females (n = 4) from each dietary treatment were sacrificed at 80 h, 6 and 10 d after vaginal plug establishment. The female reproductive tracts were excised and flushed to recover eggs and embryos or dissected to identify the number and status of the implanted fetuses. The number of eggs-embryos and/or fetuses per mouse present at the time of sacrifice were 9.8, 8.8 and 11.5 vs 8.2, 5.3 and 4.8 for the mice fed the noninfected and infected fescue seeds, respectively. Similarly, the conception rates (%) were 100, 100 and 100 vs 73, 50 and 50 for the two treatments. The mice sacrificed at 80 h and fed the noninfected fescue had 9.8 expanded blastocysts per animal, whereas those fed the infected fescue had only 4.0 expanded blastocysts. The results suggest that the infected fescue seed consumed by these mice had a significant effect on fertilization rates. More importantly, the infected fescue seed influenced negatively the development of these embryos during the embryonic-preimplantation period.     

Effects of consuming endophyte-infected tall fescue on growth, reproduction and lactation in mice selected for high fecundity

Effects of a diet containing endophyte-infected tall fescue seed (83% infected) were investigated using 2 lines of mice, one line selected for fecundity (L(+)) and the other a randomly selected control line (K). Treatments included a commercial stock diet (C), 50% stock plus 50% non-infected tall fescue seed (N), and 50% stock plus 50% infected tall fescue seed (I). The experiment was conducted using mice on respective treatments in 2 phases (successive generations), with 15 to 23 mated females per line and diet subgroups. Mated females of Phase 1 were assigned at random within line to experimental diets which were fed during gestation and through 21 d of lactation. Litters were standardized to 10 pups 1 d after birth. Stock diets were fed to all groups from Day 21 to weaning on Day 28. Weaned male and female pups were allotted to previous diets. Mated females in Phase 2 were managed as in Phase 1 through weaning at 28 d. Diets of males did not affect reproduction and data were pooled within female diets. Selected (L(+)) dams gave birth to more live pups than K dams (P<0.05) during both phases (+3.4 and +2.8 +/- 0.4 pups, respectively). Diet but not line affected littering rate of mated females in Phase 1 (71.3%, I; < 87.1%, C or 93.0%, N; P<0.05) and Phase 2 (82.1%, I < 93.8%, N or 97.1%, C; P<0.05). Diet had no effect on fecundity during Phase 1 but females on I diet had reduced (P<0.05) litter size by 1.9 and 3.2 +/- 0.5 pups compared with the females on N and C diets, respectively, in Phase 2. Feed consumption and weights of dams during lactation generally ranked C>N>I. Growth of pups during both phases also ranked C>N>I. Vaginal opening at 28 d differed by line (71.4%, K < 89.3%, L(+), P<0.05) and diet (56.8%, I < 92.0%, C or 92.2%, N, P<0.05). These results suggest both acute and chronic effects of consumption of endophyte-infected diets. Absence of line-by-diet interactions demonstrates that adverse effects were unrelated to genetic differences between lines.     

Effect of feeding tall fescue seed infected by endophytic fungus (Acremonium coenophialum ) on reproductive performance in male rats

An experiment was conducted to determine the effect of feeding tall fescue seed infected by an endophytic fungus Acremonium coenophialum on the reproductive performance of male rats. Thirty 70-day-old rats were randomly allocated to four treatments: (I) fed 50% rat chow and 50% healthy fescue seed ad libitum (control; N=9; (II) same as I but restricted to the daily feed intake of III (N=7; (III) 50% fungal-infected fescue seed and 50% chow (N=7); and (IV) a mixture of 50% laboratory chow, 25% healthy fescue seed and 25% fungal-infected fescue seed (N=7). The rats were fed these diets for 42 days. During this time, body weights were taken weekly and feed intake was taken daily. At the end of the experiment, the rats were sacrificed and the testes and epididymides were excised and measured. Sperm parameters were assessed (concentration, percentage of motility and progressive motility) at the site of the cauda epididymis; the testes were homogenized and assessed for daily sperm production potential (DSP). Concentrations of spermatozoa (x 10(6)) among the various treatments were 645.6, 486.5, 387.4 and 457.1; motility and progressive motility measurements ranged from 48 to 50% and 2.3 to 2.4 (0-4), respectively. DSP values (per gram) and testicular weight were reduced (P<0.05) in Diet III. The data suggests that 50% fungal-infected fescue seed in the diet of rats does influence the DSP, testicular parechyma and epididymal weight in the rat.     

The effect of feeding endophyte infected tall fescue seed on reproductive performance in female rats

Female Sprague-Dawley rats (Rattus norvegicus) were randomly assigned to diets containing mixtures of rat chow and tall fescue (Festuca arundinacea) seed with 0, 5, 10, 20 and 40% infection levels of Acremonium coenophialum to assess the effect of the diets on the reproductive potential of rats. Rats fed 40% infected seed had decreased body weight, decreased mean percent body weight of uteri, failed to maintain normal estrous cycles and were unable to become pregnant. Animals fed a diet of 20% infected fescue seed had extended estrous cycles. There were no significant differences among the 0, 5 and 10% dietary treatments.     

Impact of consuming tall fescue seeds infected with the endophytic fungus,Neotyphodium coenophialum,on reproduction of chickens

Most of the 14 million hectares of pastures of tall fescue (Festuca arundinacea) planted in the United States are infected with the endophytic fungus, Neotyphodium coenophialum. I examined whether the consumption of fescue seed infected with this fungus had an adverse impact on reproduction in birds. Chickens were used as the model; they were maintained on a diet of chick starter mixed in equal amounts with either infected fescue seed (fungus-fed chickens) or uninfected fescue seed (control chickens). Consumption of infected fescue seed slowed the growth rates of female chicks but not males. Fungus-fed hens gained weight more slowly than control hens and also produced fewer eggs. Egg weight and fertility were similar in both groups of hens. Fungus-fed hens were more likely than control hens to produce eggs which lacked a shell. Naive hens exhibited an aversion for infected fescue seed when the seed was first presented to them, but the aversion disappeared after the hens were placed on a diet which included fescue seed for 3 or 6 months. Hens did not discriminate between feed containing infected seed and feed containing uninfected seed.     

Effects of feeding endophyte-infected fescue seed on reproductive traits of male mice divergently selected for resistance or susceptibility to fescue toxicosis

Our objective was to determine whether consumption of endophyte-infected fescue seed affected male reproduction differently in a mouse line previously selected for susceptibility (S) to fescue toxicosis than in a line previously selected for fescue toxicosis resistance (R). For 8 weeks following weaning, 48 males per line were provided diets containing 50% of either endophyte-infected (E+) or endophyte-free (E-) fescue seed. Each male was then paired with a female for 1 week, with litter size and weight recorded from subsequent births. Males were then killed, testes and seminal vesicles were weighed, cauda epididymal sperm were collected and testis cross-sections were fixed. The E+ diet reduced litter size by 0.5 in mates of S males but increased it by 1.0 in mates of R males (line by diet interaction P=0.05). Testis traits were not affected by diet or the line by diet interaction. Sperm integrity was adversely affected by the E+ diet (P<0.01) but did not differ significantly between lines, nor were line by diet interactions important. In earlier work, the E+ diet reduced long-term reproduction by a larger amount in S- than in R-line mated pairs. Because the E+ diet had similar effects on reproductive traits in R and S males in the current experiment, we infer that the differential impact previously reported acted primarily through traits expressed in females.     

A preliminary study of growth, serum prolactin and reproductive performance of beef heifers grazing Acremonium coenophialum -infected tall fescue

In an experiment with a 2x2 factorial arrangement of treatments, 32 virgin Angus heifers were used to study effects of tall fescue endophyte Acremonium coenophialum and energy supplementation on reproductive performance. Treatments were feeding of endophyte-free (EF) or endophyte-infected (EI) tall fescue without (0%) and with energy supplementation at one percent group mean body weight (1%). Blood samples were collected at 28-day intervals for prolactin (PRL). Starting 21 days before the breeding season, blood was also collected weekly for progesterone (P(4)) and PRL. After 99 days of grazing, heifers received Syncro-Mate-B (SMB) and were then artificially inseminated over a 30-day period. Heifers on EI-0% had a lower (P<0.05) average final body weight. Highest average daily gain was observed in heifers fed EF-1% (0.98 kg/day), whereas, heifers fed EI-0% had lowest average daily gain (0.53 kg/day; P<0.05). Endophyte-infected fescue depressed serum PRL concentrations (171 and 143 ng/ml vs 70 and 85 ng/ml; EF-0% and EF-1% vs EI-0% and EI-1%, respectively; P<0.05). No differences were observed among treatments in luteal activity before or after SMB, in pregnancy rates after a synchronized estrus or in overall pregnancy rates during the 30-day breeding season. Endophyte-infected fescue decreased average daily gain and depressed serum concentrations of prolactin, but had no effect on reproductive performance as measured in this study.     

Reproductive responses to variation in temperature and food supply by house mice: II. Lactation

Lactating HS/Ibg house mice housed at 21 degrees C and 5 degrees C were assigned to 3 feeding regimes: ad libitum, daily rations of 80% of ad libitum, or 60% of ad libitum beginning on the day that they bore litters. Significant interaction between temperature and food restriction was found for litter survivorship, pup survivorship, litter size, female body weight, and cumulative biomass production. The interaction was due to a magnification of the effects of food restriction at the colder temperature: i.e. mice fed ad libitum were similar at the two temperatures, mice fed the 80% ration differed, and mice fed the 60% ration differed to a greater extent. The dominant response to food restriction was cannibalism by females, which might be associated with the rate of loss in body weight by the female on the days preceding cannibalism of one or more pups. Incidents of cannibalism tended to involve a limited number of pups and to be repeated until a sustainable litter size was reached. In 3 of the food-restricted treatments, females weaned relatively large litters of relatively small pups, but in the most severe treatment (in the group fed the 60% ration at 5 degrees C), the females weaned small litters of large pups. The patterns of cannibalism and variable relative investment in individual pups reflect the aggressive breeding strategy of this classic colonizing species.     

Genotypic and chemotypic diversity of Neotyphodium endophytes in tall fescue from Greece

Epichloid endophytes provide protection from a variety of biotic and abiotic stresses for cool-season grasses, including tall fescue. A collection of 85 tall fescue lines from 15 locations in Greece, including both Continental and Mediterranean germplasm, was screened for the presence of native endophytes. A total of 37 endophyte-infected lines from 10 locations were identified, and the endophytes were classified into five distinct groups (G1 to G5) based on physical characteristics such as colony morphology, growth rate, and conidial morphology. These classifications were supported by phylogenetic analyses of housekeeping genes tefA and tubB, and the endophytes were further categorized as Neotyphodium coenophialum isolates (G1, G4, and G5) or Neotyphodium sp. FaTG-2 (Festuca arundinacea taxonomic group 2 isolates (G2 and G3). Analyses of the tall fescue matK chloroplast genes indicated a population-wide, host-specific association between N. coenophialum and Continental tall fescue and between FaTG-2 and Mediterranean tall fescue that was also reflected by differences in colonization of host tillers by the native endophytes. Genotypic analyses of alkaloid gene loci combined with chemotypic (chemical phenotype) profiles provided insight into the genetic basis of chemotype diversity. Variation in alkaloid gene content, specifically the presence and absence of genes, and copy number of gene clusters explained the alkaloid diversity observed in the endophyte-infected tall fescue, with one exception. The results from this study provide insight into endophyte germplasm diversity present in living tall fescue populations.     

High lovastatin doses combined with hypercholesterolemic diet induce hepatic damage and are lethal to the CD-1 mouse.

The addition of 1% lovastatin (LVT) to hypercholesterolemic diets [1% cholesterol or 1% cholesterol plus 0.1% sodium deoxycholate (HD)] induced hepatic damage and was lethal to CD-1 mice in the first days of treatment; the females were more resistant than males. LVT or HD administered alone was harmless to male or female mice. After a 3-day treatment all groups that received LVT (1%, 0.1% or 0.05%) plus HD showed a higher percentage of liver weight, with respect to whole body weight. Cholesterol serum levels increased in males with HD, but remained low in female mice. In the liver, total lipids and cholesterol levels increased in male mice with HD, but cholesterol remained unchanged in females. The addition of LVT to HD prevented the increase of serum and liver cholesterol levels in male mice. These results allow us to propose the CD-1 male-mouse as a model to evaluate the toxicity of LVT or other vastatins.     

Delayed motherhood decreases life expectancy of mouse offspring

This study analyzes the long-term effects of delayed motherhood on reproductive fitness and life expectancy of offspring in the mouse. Hybrid (C57BL/6JIco x CBA/JIco) first-generation (F1) females, either at the age of 10 or 51 wk, were individually housed with a randomly selected 12- to 14-wk-old hybrid male following a breeding pen system until females reached the end of their reproductive life. Reproductive fitness of second-generation (F2) females was tested from the age of 25 wk until the end of their reproductive life. In F2 males, the testing period ranged from the age of 52 wk until their natural death. Delayed motherhood of hybrid F1 female mice was associated with a decreased percentage of male F3 offspring at birth and lower life expectancy and body weight during adulthood of F2 offspring. There was, however, no evident negative effect of delayed motherhood on several reproductive fitness variables in either male or female F2 offspring. This included between-parturition interval, litter size at birth and at weaning, body weight at weaning and preweaning mortality of F3 pups, percentage of F3 litters with at least one pup cannibalized, and time at which female and male F2 offspring ceased their reproductive life. These data clearly show that delayed motherhood in the mouse is associated with negative long-term effects on offspring survival.     

Production, Characterization, and Use of Monoclonal Antibodies Against Acremonium coenophialum

Monoclonal antibodies were produced using intact mycelium of the fungus Acremonium coenopbialum as the immunogen. During the initial stages of characterization, the antibodies were found to react to A. coenophialum, A. loliae, Epichloe typhina , and also to cross-react with some other fungi normally associated with tall fescue. Careful selection of the ELISA system in which the antibodies were used eliminated reactions to all but the two Acremonium spp. and E. typhina. Asa result it was possible to detect Acremonium spp. (presumably A. coenophialum ) sensitively and unambiguously in leaf tissue of tall fescue.     

Breeding system can affect the offspring sex ratio in Syrian hamsters

Nulliparous female Syrian hamsters were used to investigate the effect of two different breeding systems on the fertility of the female Syrian hamster. We hypothesized that females submitted to a harem system (HS) would deliver smaller and more female-biased litters than in a monogamic system. Ten female and 10 adult male hamsters housed individually (G1) were kept in a monogamic temporary breeding system, while 10 females and five males (G2) were submitted to HS with two females and a male permanently housed together since female weaning. Females from G1 and G2 delivered, respectively, 47 and 50 litters, and produced 364 (G1) and 383 (G2) weaned pups without any difference in litter size, mean weight of weaned pups and body condition of dams. Interparturition intervals were shorter and the percentage of male pups per litter was higher in the HS possibly as a result of different endocrine conditions provided by different breeding systems. Besides providing evidence that housing conditions can influence the sex of hamster offspring, our findings suggest a mechanism for the non-random distribution of male and female pups in hamster litters.     

Effects of feeding endophyte-infected (Acremonium coenophialum ) KY-31 fescue hay on the reproductive development of Holstein bulls

This study was designed to assess the effect of endophyte-infected (Acremonium coenophialum ) tall fescue (KY-31) on reproductive development in bulls. Eighteen Holstein bull calves (2 mo old) were randomly allocated to one of two dietary treatments consisting of 1) noninfected KY-31 fescue hay (NON) supplemented with grain (n=9) and 2) infected (67% infected by Acremonium coenophialum ) KY-31 fescue hay (INF) supplemented with grain (n=9). Both dietary treatments consisted of equal amounts of hay and grain. Data were collected every 14 d. Body weight, hip height and scrotal circumference did not differ (P>0.05) in the two treatments. Mean rectal temperatures also were not different in bulls (P = 0.12); however the infected bulls experienced higher rectal temperatures in all but four collection periods. Animals were sacrificed at 13 mo of age. Testicular weight and dimensions, epididymal weight and length as well as seminal vesicle weight were not different (P>0.05). Maturity of spermatozoa taken from each cauda epididymides was assessed by the incidence of cytoplasmic droplets and was not different (P>0.05) between treatments. Daily sperm production potential was not different (P>0.05) between treatments; however, large variations were noted among the infected bulls. Blood testosterone levels were not different (P=0.29) between the two dietary treatments, but were different over time (P<0.001) with NON and INF bulls having 2.14 +/- 0.21 and 2.41 +/- 0.22 ng/ml, respectively. Prolactin levels were different (P<0.02) between the NOn and INF bulls, 29.35 +/- 3.35 vs 18.31 +/- 3.39 ng/ml, respectively; and over time (P<0.001). The data generated in this study showed some important biological trends. Overall, the results indicate that endophyte infected KY-31 fescue hay fed to growing bulls did not appear to have severe detrimental effects on body growth or reproductive development. However, additional studies will be necessary to further delineate the patterns established in this study.