title: Association between heterophil/lymphocyte ratio, a marker of 'resistance' to stress, and some production and fitness traits in chickens.
abstract: 1. A stock of cross-bred CD hens was divided into 'resistant' (R) and 'sensitive' (S) to stress on the basis of the heterophil/lymphocyte (H/L) ratio using the lower 99% confidence limit method for selection. A first generation was produced from these R and S females mated with similarly selected R and S local Barred males. The association between 'resistance' and some production traits was investigated. 2. The proportions of R:S among CD females and Barred males was 51.2:48.8 and 52:48, respectively. Mean H/L ratios for Barred males and females, respectively, were 0.87 +/- 0.03 and 0.83 +/- 0.03 (P > 0.05). 3. Compared with the S group in CD females, the R group had greater egg production (59% vs 51%), egg weight (65.5 g vs 62.6 g) and body weight at 39 weeks (115 g heavier). 4. The superiority of R in terms of proportion of fertile eggs, hatchability and the proportion hatched from those set amounted to 4.8, 6.1 and 5.4%, respectively. 5. The proportion of dead embryos in the R group (5.4%) was lower than in the S group (9.3%). 6. With the F1 generation the R chicks were heavier at hatching. 7. Percentage mortality of male F1 chicks, from hatching to 4 weeks and from 4 to 8 weeks, was lower in the R group. A similar, but non-significant, trend was noted for R females. 8. The progeny of the R group was heavier than the S progeny at 4 and 8 weeks and also the percentage dressed weight of males was greater at 8 weeks. The R group was heavier than the S group at 4, 8 and 12 weeks. 9. These results suggest that selection for general 'resistance', on the basis of the H/L ratio using the 99% lower confidence limit method of selection, is positively correlated with several important production and reproduction traits. Establishing resistant lines with high production rates seems feasible.
authors.affiliation: Institute of Genetic Engineering & Biotechnology, College of Veterinary Medicine, Baghdad, Iraq. profmurrani@yahoo.com
authors.forename: W K
authors.initials: WK
authors.lastname: Al-Murrani
authors.forename: A J
authors.initials: AJ
authors.lastname: Al-Rawi
authors.forename: M F
authors.initials: MF
authors.lastname: Al-Hadithi
authors.forename: B
authors.initials: B
authors.lastname: Al-Tikriti
mesh_terms: D000818:Animals; D015415:Biomarkers; D002452:Cell Count; D002645:Chickens / Q000235:genetics / Q000502:physiology*; D005260:Female; D006262:Health; D008214:Lymphocytes / Q000097:blood*; D008297:Male; D010058:Oviposition; D013312:Stress, Physiological / Q000662:veterinary*
chemical_list: D015415:Biomarkers