Cryopreservation of rooster semen in thirteen and sixteen percent glycerol

An effective method for improving the fertility of glycerol-exposed poultry semen

Semen cryopreservation is necessary for banking germplasm from critical poultry stocks. To date, glycerol is the most effective cryoprotectant for poultry sperm; however, the contraceptive effects of glycerol require a significant reduction of the cryoprotectant from thawed semen before artificial insemination (AI). The effectiveness of glycerol reduction by dialysis, Percoll density gradient centrifugation, or washing through 12% (wt/vol) Accudenz was evaluated by fertility trials with highly inbred chicken research lines and commercial turkey lines. Semen was extended 1:1 and then diluted with glycerolized extender to yield a final 11% (vol/vol) glycerol concentration. Glycerolized rooster semen was aliquoted for control, Accudenz centrifugation, and dialysis treatments. A total of 90 pure line and 85 F1 hybrid chicken hens were each inseminated with 100 x 10(6) sperm at 7-d intervals for 4 to 6 wk. All eggs from the glycerolized control semen treatments were infertile, and fertility rates from dialyzed semen decreased steadily from 26.4 to 0% within the first 4 wk for the pure lines. In contrast, fertility rates for Accudenz-processed semen increased from 17.9 to 37.17% during the first 4 wk. Similar fertility rates occurred with the F1 hybrid cross lines. For turkey fertility trials, the dialysis treatment was not used; glycerolized turkey semen was processed by Accudenz or Percoll centrifugation to reduce glycerol. A total of 36 hens were inseminated with 150 x 10(6) sperm at 7-d intervals for 6 wk. Similar to the chicken trials, fertility rates of Accudenz-processed semen steadily increased to 49.4% by the sixth week of insemination. The average fertility of Percoll-processed semen was only 19.1%. These data demonstrate that Accudenz centrifugation is an acceptable glycerol reduction method for nonfrozen poultry semen.

DMF effects on frozen gander semen

1. The objective of the present study was to determine if the age of semen donors affects the susceptibility of spermatozoa to freezing and whether DMF (dimethyl formamide) inseminated with freeze-thawed gander semen decreases fertility. 2. Semen was collected 3 times a week by dorsal-abdominal massage from two groups of White Italian ganders: 3 and 2 years-old. Both samples were diluted, mixed with DMF to a final concentration of 6% (v/v), pre-frozen and transferred into LN2. 3. Twice a week, the freeze-thawed semen was used for insemination of two groups of geese at a dose of 4 to 16 million live morphologically normal spermatozoa. One group was inseminated immediately after thawing, the 2nd with semen from which the DMF was removed. 4. Donor age had no effect on the spermatozoa's aptitude for freezing. The differences in quality and quantity of fresh and freeze-thawed semen produced by 3 or 2 year-old ganders were not significant. 5. The presence of DMF in the inseminated freeze-thawed semen did not affect the reproductive efficiency of spermatozoa. The fertility rate obtained with semen inseminated either with or without the cryoprotectant averaged 92.9% and 87.2% respectively. The hatchability of set eggs was 81.1% and 79.9% and, the hatchability of fertile eggs amounted to 87.3% and 89.4%.

Effects of semen filtration and dilution rate on morphology and fertility of frozen gander spermatozoa

Feces, urates or dirt originating from feathers often contaminate gander semen during collection, threatening its fertilizing ability. Seminal plasma used as a diluent has a similar effect, particularly on spermatozoa subjected to cryopreservation or short-term storage under refrigeration. The aim of the experiments was to evaluate the effects on spermatozoa motility, morphology and fertilizing ability after minimizing the influence of the contaminants by semen filtration or dilution prior to freezing. Pooled semen, collected twice a week from 9 White Italian ganders by dorso-abdominal massage, was divided into two parts. One sample was filtered and both were diluted in 1:1 or 1:0.5 (v/v) with EK diluent, equilibrated for 15 min at +4 degrees C, mixed with dimethyl-acetamide (DMA) in the final concentration 6% (v/v) and frozen to -140 degrees C in a computerized freezer, at a rate of 60 degrees C/min. In fresh and processed (filtered, freeze-thawed) semen were examined the spermatozoa motility and morphology, and fertilizing ability for freeze-thawed semen, both for unfiltered and filtered. In freeze-thawed semen no tangible differences due to experimental factors were observed in motility and percent of live spermatozoa in total. On average 35 to 42% of the spermatozoa survived the freezing process, but only 10 to 15% were normal, without any damage visible under the light microscope. The fertility of unfiltered freeze-thawed semen inseminated twice a week in a 0.2 mL dose (about 3 to 5 x 10(6) of live normal spermatozoa each) averaged 66.1% and hatchability of the set eggs 57.1 and 86.5% of the fertile eggs. The fertility obtained after the insemination with semen filtered prior to freezing was lower (64.3%), but hatchability was slightly higher (58.6 and 91.1% of set and fertile eggs, respectively). The duration of fertility for filtered semen was longer than that for unfiltered, 10 days after the last insemination the eggs were still fertile. The fertility results of freeze-thawed gander semen were very promising taking into consideration the small amount of inseminated live normal spermatozoa and it is possible to improve this result by increasing the number of spermatozoa in the insemination dose.

Storage of poultry semen

Methods of semen collection and artificial insemination (AI) in poultry, requirement for diluents, methods of liquid and frozen storage of avian semen and evaluation of spermatozoa after storage for fertilizing ability are reviewed. Frozen storage of semen from non-domestic birds is also briefly discussed.