When rooster semen is exposed to Lactobacillus fertility is reduced

Abstract

Lactobacillus resides in the hen’s gastrointestinal tract, vagina and cloaca. When fed to hens, Lactobacillus has improved egg weight, size and shell strength. However, data from our lab suggests Lactobacillus may be detrimental to semen and possibly fertility. Therefore, the objective of this study was to determine if semen exposed to Lactobacillus affected fertility in hens. For the experiment, semen was collected from 40 roosters and used to create 4 treatments: saline, broth, 103 cfu/mL of Lactobacillus and 106 cfu/mL of Lactobacillus. Each treatment was diluted 1:1 with pooled semen and sperm quality index readings were obtained prior to insemination. Eighty hens in each treatment were equally divided among 10 blocks and inseminated. Eggs were collected from 2 to 7 d post-insemination (DPI) and hens were artificial insemination again on DPI 8, eggs were collected for another 7 d. Eggs were incubated for 10 d, candled for fertility and a portion of the eggs were examined for Lactobacillus. The entire experiment was repeated twice. Semen quality was within the normal range for treatments 1, 2 and 3, but semen from treatment 4 was immotile before insemination. Additionally, 84% of the eggs from treatments 1, 2 and 3 were fertile; however, all eggs from treatment 4 were infertile. There was no difference between treatments for Lactobacillus counts in the yolk or on the shell. However, fertility and Lactobacillus shell counts declined over DPI. In conclusion, if Lactobacillus exceeds 106 cfu/mL in the hen or roosters reproductive tract, fertility could be impacted.