Effects of immunomodulatory nutrients on growth performance and immune-related gene expression in layer chicks...

Immunomodulatory nutrients alter the immune response to pathogens. This study was conducted to determine the effects of immunomodulatory nutrients on the immune response to a lipopolysaccharide (LPS) challenge of layer chicks fed supplemental corn oil (control; 3%), fish oil (3%), conjugated linoleic acid (CLA; 1%), lutein (0.05 g/kg), or vitamin E (90 I.U./ kg). Four-week-old layer chicks were allotted to 10 treatment groups arranged as a 2 × 5 factorial with 2 sexes and 5 dietary treatments (TRT; 5 replicate pens of 2 male and 2 female chicks per TRT). After a 2-week diet adaptation, all birds were injected intraperitoneal with 1.5 mg/kg BW LPS. Twelve hours post challenge, samples were collected. Fish oil fed birds had greater (P = 0.03) spleen weight (% final BW) than the CLA fed birds. In the liver, the fish oil TRT had higher (P = 0.040) IL-12 expression than the corn oil TRT, but the corn oil TRT had greater (P = 0.001) IL-4 expression than the CLA, lutein, and vitamin E TRT. There was a main effect of sex of the birds on growth parameters at 12 h post LPS challenge in which male birds had greater beginning BW (P < 0.001), final BW (P < 0.001), and greater 12-hour BW loss (P = 0.020) than the female birds, but not relative weight loss. There were also main effects of sex on immune-related gene expression with the females having greater gene expression than the males in the duodenal mucosal scrapings [IL-1β, IL-12, and TLR-4 gene expression (P = 0.026, 0.011, and 0.002, respectively)]; liver [IL-10, IL-4, and iNOS gene expression (P = 0.017, 0.032, and 0.006, respectively)]; and spleen [IL-1β, IL-10, IL-4, and iNOS gene expression (P = 0.001, 0.001, 0.001, and 0.005, respectively)]. Therefore, each immunomodulatory nutrient added to the diets of layer chickens resulted in different immune responses to an LPS challenge.