Metabolism and Nutrition: Probiotic and Prebiotic

Canthaxanthin (Cxn) is a fat-soluble red carotenoid pigment and is reported to be immunomodulatory. Broiler breeder hens were fed 0 ppm (Control), 6 ppm or 12 ppm Cxn to determine the effect of maternal dietary Cxn on chicks hatched from hens at 31 (Early), 45 (Mid) and 57 (Late) wk of age. Whole blood was obtained at 1 and 4 d of age to assess the number of cells able to engulf at least one Escherichia coli (% phagocytosis), average number of E. coli/cell (phagocytic capacity), and E. coli bactericidal capacity ex vivo. Egg and chick liver Cxn were determined. Eggs from 12 ppm hens had 40% more Cxn than eggs from 6 ppm hens, which in turn had 30% more Cxn than eggs from Control hens (P < 0.0001). Liver Cxn of 12 ppm chicks was 126% greater (P < 0.0001) than 6 ppm chicks; 6 ppm chicks had 67% more Cxn than Control chicks. Chick liver Cxn content decreased by 37% in 6 ppm chicks and 22% in 12 ppm chicks (P < 0.01) from Early to Mid with no subsequent changes; there was no age effect in Control chicks. There was a 22% reduction (P < 0.03) in phagocytic capacity at 1 d in 6 ppm chicks relative to Control and 12 ppm chicks. At 4 d of age, 12 ppm chicks had 20% lower (P < 0.03) E. coli bactericidal capacity than 0 or 6 ppm chicks. E. coli bactericidal capacity increased from 1 to 4 d in Control and 6 ppm chicks, but not in 12 ppm chicks (P < 0.02). Chicks from 6 ppm hens had the greatest E. coli bactericidal capacity among chicks hatched from Mid hens, even though they had the lowest E. coli bactericidal capacity among chicks from Early hens. Among Late hens, Control chicks had the greatest E. coli bactericidal capacity, while 12 ppm chicks had the lowest E. coli bactericidal capacity. Greater levels of dietary Cxn increased egg and chick liver Cxn, although liver Cxn content decreased as hens aged. Feeding hens 6 ppm Cxn appeared to increase early chick E. coli bactericidal capacity in d-old chicks, in spite of decreased phagocyte capacity, indicating an overall increase in innate immune function. However, this effect was dependent on hen age.