Location: Avian Disease and Oncology ResearchTitle: Reproductive performance assessment of two White Leghorn lines free of endogenous viruses
Submitted to: Poultry Science Association Meeting Abstract
Publication Type: Abstract Only
Publication Acceptance Date: 4/5/2017
Publication Date: 7/12/2017
Citation: Kulkarni, G., Dong, K., Zhang, H. 2017. Reproductive performance assessment of two White Leghorn lines free of endogenous viruses. Poultry Science Association Meeting Abstract. Available:http://www.poultryscience.org/psa17/abstracts/32.pdf.
Technical Abstract: Two of the chicken lines that USDA-ARS Avian Disease & Oncology Laboratory (ADOL) have developed and maintained are line 0 and line 0.TVB*S1 (also known as rapid feathering susceptible or RFS). Line 0 was developed in the 1980s (Bacon et al., 2000), and RFS was developed in 2007 (Zhang et al., 2008). These two lines of chickens are free of subgroup E avian leukosis virus (commonly referred to as endogenous virus free or ev free). The reproductive performance of these rare ev-free lines has not been assessed since their establishment. Reproductive records from the past five years (2012-2016) were used to retrospectively assess the reproductive characteristics of fertility, embryo mortality and hatchability, which is vital to ensure future reproductive success of the lines and to meet research needs for embryos and chicks of the lines. The realized fertility for line 0 ranged from 85% to 93.4%, and for line RFS, from 74.2% to 91.1% during the past five years. The average fertility of line 0 (88.9%) was higher than line RFS (82.5%; P < 0.01). Statistical analysis suggested that genetic line and the reproductive year both significantly affected the fertility characteristics in addition to a line by year interaction (P < 0.001). Embryo mortality ranged from 5.5% to 10.6 % and 6.4% to 10.8% during the years for line 0 and line RFS, respectively. The embryo mortality fluctuated from year to year with an overall average of about 7.9% for both lines. The hatchability ranged from 83.3% to 87.3% and 78.3% to 86.6% for line 0 and line RFS, respectively. The overall average of hatchability was 85.4% and 82.9% for line 0 and line RFS, respectively. Statistical analysis indicated that a line by year interaction had a significant influence over the hatchability characteristics (P < 0.05). In comparison with the reproductive performance of 21 inbred lines of White Leghorns that carry multiple ev genes in their genome (lines 63, 72 and 19 recombinant congenic strains) and were maintained under the same conditions at ADOL (Kulkarni and Zhang, 2015), the average fertility of these two ev-free lines is comparable, the embryo mortality is significantly lower, and the hatchability is significantly higher. The findings of this study also suggested that endogenous viral genes are non-essential to reproductive performance in chicken.