Investigating the effect of blood gas parameters as indicator traits in selection index to reduce ascites susceptibility in broilers

Ascites syndrome is a metabolic disorder in fast growing broilers. Due to high mortality, the poultry industry carries economic detriment. Ascites related traits have high heritability which shows impressibility of genetic factors. Therefore, genetic selection against ascites susceptibility is possible. The aim of the current study was to evaluate consequences of alternative selection indices to reduce ascites susceptibility using deterministic simulation. The traits investigated were partial pressure of oxygen in venous blood, bicarbonate, oxygen saturation in venous blood and ratio of right to total ventricular weight. In addition, the consequences of having information on the underlying genes (MAS) were identified. Alternative selection strategies were compared based on the selection response for body weight and ascites susceptibility, accuracy of selection as well as the rate of inbreeding. The results showed that by including blood gas parameters as indicator traits to ascites, reduced genetic response for BW5 based on indices number 1, 2, 3, 4, 5, 6 were 20, 23, 69, 16.8, 18.8 and 15.7 percent of genetic response for BW5 based on single trait selection, respectively. The results of schemes comprising QTL information of ascites susceptibility showed that ascites susceptibility can be reduced appropriately with considering different values of genetic variance due to QTL. This reduction was lower by including QTL information and was about 2.8 percent for BW5 in which QTL explains 50% of the genetic variance of ascites syndrome. The profitability of MAS was depended on economic analysis of animal breeding programs.