No abstract

Parthenogenesis, embryonic development of an unfertilized egg, was studied for many years in turkeys. In fact, as many as 49% of unfertilized Beltsville Small White turkey eggs develop embryos. However, no research exists on parthenogenesis in quail. The Chinese painted quail is a close relative of the more common Japanese quail and, unlike turkeys or chickens, the small Chinese painted quail reaches sexual maturity rapidly, making it a great candidate for further research on parthenogenesis. Obviously, a better understanding of avian parthenogenesis should increase our knowledge of avian fertilization and early embryonic development. Therefore, we determined if unfertilized Chinese painted quail hens produce embryos. Second, we explored the possibility that position of the egg within the clutch influences parthenogenesis. When initial secondary sexual plumage was apparent at 4 wk of age, male chicks were separated from females to prevent fertilization. Hens were placed in individual cages near sexual maturity, at approximately 6 wk of age. Individual eggs were collected daily and labeled with hen number and date. Eggs were stored for 0 to 3 d at 20 degrees C before incubation at 37.5 degrees C. After 10 d of incubation, approximately 4,000 eggs from 300 laying hens were examined for embryonic development under a magnifying lamp. On average, 4.8% of the unfertilized eggs contained an abortive form of embryonic development consisting of undifferentiated cells and unorganized membranes. Approximately 27% of the laying hens produced at least 1 egg with parthenogenic development. However, about 10% (30) of these hens exhibited a predisposition for parthenogenesis by producing 2 or more unfertilized eggs with embryonic development. Twenty percent of the eggs from 2 hens produced embryonic development. Additionally, the first egg laid in a clutch was most likely to produce embryonic development, with a steady decline in the percentage of eggs with embryonic development as position in the clutch increased. In conclusion, the Chinese painted quail does exhibit parthenogenesis and clutch position influences the rate of naturally occurring parthenogenesis.

The purpose of the present study was to define the role of the male broiler breeder in heat-induced infertility. Seventy-two Arbor Acres roosters were individually caged at 21 wk of age and divided equally among three heated (H) and three control (C) temperature chambers. Control temperature chambers were held at 21 C. After an 8-wk pretreatment period (20 C), an 8-wk treatment period was conducted in which the temperature in all three of the H chambers was varied from week to week according to the following schedule: Week 1, 27 C; Week 2 through Week 4, 32 C; and Week 5 through Week 8, 21 C. On a weekly basis, semen was pooled by room and inseminated into 12 groups of 10 hens each (2 groups per room). During the 1st wk when males were maintained at 27 C for 12 h, in vivo sperm-egg penetration was reduced by 48% as compared to data obtained when males were maintained at 21 C. Fertility, in vivo sperm-egg penetration, and uterovaginal sperm storage were decreased when semen from males exposed to 32 C was used to inseminate hens as compared to insemination with semen from C males. However, during this same period, the ability of sperm to bind and penetrate the egg, as determined by in vitro sperm-egg penetration, was similar between sperm from C and H males. After lowering the temperature in the H chambers back to 21 C, in vivo sperm-egg penetration as a result to insemination with semen from H males was analogous to results obtained when C males were used for insemination. Immediately after decreasing the temperature in the H chambers, fertilization of eggs by sperm from H males increased to a level similar to that obtained when eggs were fertilized by sperm from C males but then declined again during the later weeks.

This study evaluated the influence of inoculation of different nutrients into eggs of 18-d-old broiler embryos. On d 18 of incubation, before transferring, eggs were injected with a solution containing either maltose, a multivitamin supplement, zinc-glycine, glutamine, a mixture containing all these elements, or sodium chloride (control). After hatching, 2,400 male broiler chicks were placed in an experimental broiler house and distributed into 60 floor pens in a completely randomized design comprising a 2 × 6 factorial arrangement of treatments (2 egg weights × 6 solutions), for a total of 12 treatments. Birds and feed consumption were measured weekly. At 42 d of age, 3 birds per replicate pen were randomly selected for processing. Birds derived from heavier eggs had greater hatchability and hatching weight. At 42 d of age, birds from heavier eggs had higher BW, carcass weight, and breast meat weight. The livability of birds derived from heavy eggs was higher at 7 and 14 d of age. The in ovo inoculation of the nutrients to 18-d-old embryos did not influence live performance or carcass traits. The technique of in ovo inoculation of certain nutrients may be used in industrial poultry production, but further studies are required to define the best solutions or mixture of nutrients to be used.

Male fertility is often evaluated by measuring sperm parameters, including concentration, viability, and motility. This is important because after copulation occurs, sperm must overcome many barriers in the female reproductive tract to fertilize the ovum. In mammalian species, sperm have been shown to have reduced motility when bacteria are present. In male broiler breeders, bacteria have been associated with spermatozoa, but their effect on motility has not been investigated. The sperm quality index is a modern rapid method of evaluating avian sperm motility. Therefore, the objective of this study was to use the sperm quality index to determine if broiler breeder sperm motility is reduced when semen is exposed to various bacteria. In this experiment, semen was collected from 20 broiler breeders to obtain a pooled neat semen sample. Six different intestinal bacteria, Salmonella enterica, Escherichia coli, Campylobacter jejuni, Clostridium bifermentans, Lactobacillus acidophilus, and Bifidobacterium animalis were cultured overnight. For each bacterium, 50 µL of semen was diluted in 450 µL of saline, sterile broth, or the overnight culture, creating 3 treatments. The experiment was repeated twice. In each treatment, 3 replicates were evaluated at 0 and 10 min postinoculation, creating a completely randomized design with a split plot over time. Also, the pH was measured for each treatment at 0 and 10 min. The results indicated that all broths containing bacteria immediately reduced broiler breeder sperm motility when compared with the controls (P < 0.0001), but broths containing Bifidobacterium or Lactobacillus virtually made sperm immotile. Although broth containing Salmonella, Campylobacter, and Bifidobacterium immediately reduced sperm motility, the reduction did not change over time. Broths containing E. coli, Clostridium, and Lactobacillus reduced sperm motility immediately, but over time motility continued to decrease. However, pH was increased when semen was exposed to the E. coli and Campylobacter treatment, but when semen was exposed to Bifidobacterium and Lactobacillus treatments, pH was reduced. In conclusion, the results indicate that bacteria can reduce broiler breeder sperm motility upon exposure.

An experiment was conducted to test the effect of age (male and female) on the number of spermatozoa penetrating the perivitelline layer (PL) overlying the germinal disc (GD) in broiler breeders. Eighty young broiler breeder hens (39 wk old, Y), and 80 old spent broiler breeder hens (69 wk old, O) were randomly divided into eight groups of 20 hens each by age. Hens were inseminated weekly for 4 consecutive wk with 5 x 10(7) pooled sperm/50 microL from either young or old broiler breeder males. Sperm penetration (SP) of the PL at the GD was assessed in a random sample of 12 oviposited eggs from each hen group for each day postinsemination, with the remainder of the eggs incubated for 10 d to obtain fertility values. For the main effect of sex, and for age within sex, there were differences in mean SP (7.3 vs 4.8; Y vs O hens; P < 0.02) and fertility (73.7 vs 54.9%; Y vs O hens; P < 0.002) values. Old males had higher mean SP values and fertility (7.2 and 70.6%) than young males (4.8 and 58.0%; P < 0.03 and 0.01, respectively). Following artificial insemination of a constant number of sperm, age of hens appears to contribute more to the decrease in SP and fertility than the age of male broiler breeders. Eggs were obtained from naturally mated broiler breeder flocks from different strains (A and B), lines (male and female), and ages. There was an effect on overall mean SP values due to strain (105.8 vs 78.6 holes per GD area; Strains A and B, respectively; P < 0.0001), and line within Strain B (106.4 vs 50.8 holes per GD; male and female line, respectively; P < 0.0001). There was a quadratic relationship between SP of the PL and age in Strain A with values ranging from 153.3 to 20.0 holes per GD area (P < 0.003). In Strain B, SP holes in the PL decreased in the male line due to age (127.8 to 59.7 per GD; P < 0.01), with an effect of age on the female line also (62.1 vs. 37.8 holes per GD; P < 0.05).

Research has shown that trace elements, such as Se, Mn, and Zn, can alter reproductive functions. The aim of the current study was to evaluate the sperm quality index (SQI) and sperm viability as affected by various levels and sources of Se, Mn, and Zn when added in vitro to broiler breeder semen. In vitro treatments consisted of the following sources and levels of minerals: Control, no minerals added to sperm; seleno L-methionine, 4 levels ranging from 8.78 to 7,896 microg/L; sodium selenite, 4 levels ranging from 8.78 to 7,896 microg/L; MnSO4, 8 levels ranging from 6,500 to 65,000 mg/L; Zn 180 (Zinpro Corporation), 4 levels ranging from 0.65 to 650 mg/L; and ZnSO4, 4 levels ranging from 0.65 to 650 mg/L. The addition of 7,896 microg of sodium selenite/L to semen was detrimental to sperm motility. Also, MnSO4 adversely affected SQI and sperm viability at concentrations of 6,500 mg/L and greater. Sperm viability was decreased when 650 mg/L of Zn 180 was added to semen. Sperm motility was depressed by exposure to Zn 180 at 650 mg/L and ZnSO4 at 65 and 650 mg/L. Our results suggest that these trace minerals must act at the reproductive tissue level during spermatogenesis to improve semen quality. Direct in vitro application of these elements to semen appears to be detrimental to spermatozoa.

A new instrument for assessing mammalian semen attributes, the Sperm Quality Analyzer, was evaluated as a potential tool for determining rooster sperm quality. The Sperm Quality Analyzer measures the "activity" of sperm in a semen sample as the sperm motility index (SMI). The SMI is defined as the number and amplitude of deflections in a light path per second as a result of sperm movement within a capillary tube. In the present study, effects of sperm concentration, viability, and motility on the SMI were evaluated. Peterson broiler breeder males (n = 40) were used as semen donors. In the initial experiment, semen was diluted from 2- to 25-fold and SMI readings were obtained. The SMI was very low in neat semen samples but increased when semen was diluted up to threefold. However, at dilutions greater than fivefold, the SMI decreased. Apparently, sperm concentration in undiluted semen is so great that sperm are unable to move freely within the capillary tube. Maximum SMI values were obtained at sperm concentrations of approximately 1 billion sperm per milliliter. When thawed, dead sperm were mixed with incubated, live sperm, the SMI decreased with decreasing sperm viability even though sperm concentration was constant. Obviously, fewer sperm move across the light beam as sperm mortality increases. When motile, aerobically incubated sperm were mixed at different rates with immotile, anaerobically incubated sperm samples, the SMI increased with increasing concentrations of motile sperm, whereas total sperm concentration was static. In addition, the SMI was strongly correlated with motility scores obtained by microscopic analysis. The Sperm Quality Analyzer provides an estimate of the overall quality of sperm from broiler breeder males by reflecting sperm concentration, viability, and motility in a single value, the SMI.