This experiment was carried out to investigate the combination effects of organic and inorganic chromium (Cr) on egg production, egg quality, reproductive response, and immune status of breeder quails and their offspring under heat stress. A total of 140 7-week-old Japanese breeder quails (120 females and 20 males) according to a completely randomized design were used in four treatment groups (five replicate and seven birds per each) lasted for 8 weeks. Quails exposed to 35 °C for 8 h/day for induction of cyclic heat stress treatments consisted of diets supplemented with (1) 1 mg CrCl3 per kilogram of diet as control (CNT); (2) 1 mg Cr-L-Met per kilogram of diet as organic Cr (OCr); (3) 0.5 mg CrCl3 plus 0.5 mg Cr-L-Met per kilogram of diet (ISO); (4) 1 mg CrCl3 plus 0.5 mg Cr-L-Met per kilogram of diet (On-top). Productive performance and egg quality parameters were determined weekly. Fertility, hatchability, and embryonic mortality were measured at the end of experiment. Humoral immunity was assessed by primary and secondary antibody titer in sheep red blood cells (SRBC) and Newcastle disease (ND) tests. Cell-mediated immunity was assessed by the cutaneous basophil hypersensitivity (CBH) test to phytohemagglutinin (PHA) at days 20 and 45 of age. White blood cell count and immunoglobulin Y (IgY) content in serum and yolk of breeders and in serum and yolk residues of offspring were also measured. Results showed that maximum egg production, egg shell thickness, and Haugh unit were observed in birds fed ISO and On-top diets (P ≤ 0.05). The highest (P ≤ 0.05) antibody levels in ND test were observed in birds fed with OCr, ISO, and On-top diets. The highest cellular response (P ≤ 0.05) was in 12 h after primary PHA injection and 12 and 24 h after secondary PHA injection in birds fed with On-top diets. The highest count of heterophil and (H/L) were gained in breeder quails fed with CNT diet, and the lowest of them were reached with On-top diet (P ≤ 0.05). Results showed that the highest IgY level in serum of breeder and their offspring and that of yolk suck and egg yolk were observed in birds fed with On-top diet (P ≤ 0.05). These results suggest that extra supplemental organic Cr in combination with CrCl3 could lead to higher egg production, egg quality, and immune status of breeder quails and their offspring.
Breeder quail; Chromium; High ambient temperature; Immune responses; Immunoglobulin Y; Reproductive performance
*The Normal Quail IgY used in this research was produced by Gallus Immunotech.