Effect of in ovo (embryonic) inoculation of Arginine on pulmonary artery, right ventricular and lugs morphological changes in induced ascites broiler chickens

In order to evaluate the influence of yolk in ovo (embryonic) inoculation of arginine in fifth day of incubation on pulmonary artery, right ventricular and lungs morphological changes in induced ascites broiler chickens, two separate experiments were designed. In first experiment, 560 fertile eggs divided in 7 groups and 4 subgroups and levels of 0, 20, 40, 60, 80 and 100 mg arginine per mL normal saline injected on yolk in fifth day of incubation and a group had no injection. In 20th day of incubation, nitric oxide (NO) and endothelin 1 (ET1) in the pulmonary artery in 2 fetuses per subgroup was measured. The 40 mg arginine per mL normal saline was the most appropriate level of arginine injection (lowest ET1 was 89.93 ng/100 mg tissue and highest NO was 13.35 µmol/100mg tissue). In the second experiment, 300 fertile eggs divided in 2 groups. In first group 40 mg of arginine per mL normal saline injected to 150 fertile eggs. The chickes were separated by sex after hatch. From day 21 to day 48 the rearing temperature reduced to 14-16 ℃ and ascite was induced. In ovo injection of arginine reduced ascites mortality (17.6 vs 48.8%), but the main effect of sex was insignificant (P>0.05). Main effect of arginine injection increased inner pulmonary artery area (3.47mm2 vs 2.67mm2) In treatments without arginine injection compared with those having argenine injection rather than arginine injection some gaps was observed in the lung cell layers. In ovo injection of arginine lowered the mortality rate due to ascites through increasing the pulmonary artery diameter and preserving the natural layers in the lungs.