Influence of natural pigment sources on growth performance, live and postslaughter skin pigmentation, serum carotenoids and lipid profile of broiler chickens
Carotenoids are bioactive molecules synthesized in plants and are important in the development of hues in the skin and muscles of chickens, which influence consumer perception and consumption. The extent of absorption and assimilation of carotenoids from different plant-based pigment sources was explored in this study. One hundred and twenty-eight day old broiler chicks were allotted to four treatments, four replicates of eight chicks each. Chicks were fed a starter diet for 21 days and thereafter grower-finisher diets containing one of moringa (Moringa oleifera), baobab (Adansonia digitata) leaves, roselle (Hibiscus sabdariffa) calyces and orange (Citrus x sinensis) rind- at 4% of their diet for 35 days. Skin pigmentation was scored in the apterylum region and shank of live broiler chicken weekly and in the breast, back, vent, shank and abdominal fat of 56 day old broiler chicken post-slaughter using a DSM broiler colour fan. Serum carotenoids measured as red and yellow pigments and serum lipid profile were determined by a spectrophotometric method. Pigmentation was higher in the shank, with visual score ranging from 101.0 – 103.78 and least in the skin of the back ranging from 101.0 – 102.0 (P<0.05), while pigmentation in the vent and breast were similar for chickens on the different dietary treatments. Higher live and post-slaughter skin pigmentation was observed in chickens on moringa diet with visual score ranging from 103.1. – 103.75 and 102.0 – 103.78 respectively, and lower pigmentation in those on roselle diet, ranging from 101.13 – 101.32 and 101.0 – 101.34 respectively. Shank pigmentation score peaked at 21d for chickens on baobab (102.32) and roselle (101.32) diets, and 35d for chickens on the moringa and orange rind (103.75 and 102.06, respectively) diets. Apterylum pigmentation peaked at 21d for chickens on baobab (101.54) and orange (101.40) diets and 28d for chickens on the moringa (102.40) diet. Dietary sources of carotenoids did not significantly influence yellow pigment deposition in the serum between 21-28d of exposure while red pigment deposition in the serum was unaffected by the dietary treatments after 28d of exposure. Yellow pigment composition of serum was significantly (P<0.05) lowest in chickens on moringa diet at 14 and 21d (19.84 and 18.54 ppm). A similar trend was observed for red pigment composition of serum of chickens on moringa diet at 28 and 35d (19.60 and 18.36 ppm). However the serum lipid profile of chickens in the study was not affected by the different pigment sources in their diets. Absorption and assimilation of carotenoids varied for the different carotenoid sources assessed, with Moringa oleifera leaves significantly improving live and post-slaughter pigmentation of broilers.