Dietary supplementation with organic choline improves layer performance, egg production, and egg quality

Choline is vital for liver function and productivity in laying hens, serving as a methyl donor, lipotropic agent, and precursor for key biomolecules like phosphatidylcholine and acetylcholine. Methionine also donates methyl groups and supports protein and feather development. This study investigated choline propionate, a novel organic choline source, versus conventional choline chloride in laying hen diets. A total of 576 Hy-Line Brown hens (50 wk old) were allocated to two trials (288 birds each) with four treatment groups (6 replicates of 12 hens). Trial 1 evaluated choline propionate (120 ppm, 160 ppm) and choline chloride (160 ppm) in a choline-deficient diet. Trial 2 assessed methionine-sparing effects with a 15% methionine and cysteine reduction. Experimental data was analyzed using analysis of variance (ANOVA) procedure of SAS, by the comparison of Least Square Means (LSM) using either Tukey's parametric test for egg production performance, egg quality parameters, serum biochemical markers, lipids, and fatty acid profiles or Kruskal-Wallis non-parametric test for liver histopathological and liver lesion scoring. In Trial 1, both choline sources improved egg production and quality. Egg production rate with choline propionate supplementation achieved more than 88% compared to 32% in the control group. Overall, significant egg weight increase of more than 3% was recorded for the 120 and 160 ppm choline propionate groups compared to the control. Egg shell strength improved by more than 30% with the choline propionate supplementation compared to the control. Choline propionate at 160 ppm showed significant enhancement of yolk color by 2% (P < 0.0001) when compared to the control group. A notable 25% lower serum aminotransferase (AST) levels was observed in the 160 ppm choline propionate group, suggesting a liver protection function compared to the control group. In Trial 2, methionine reduction had no significant effect on performance, with egg production improved numerically in choline-treated groups, suggesting mild methionine-sparing activity. Hens supplemented with choline propionate showed no visible signs of liver steatosis or discoloration, suggestive of improved hepatic condition while controls showed signs of fatty liver traits. Choline propionate demonstrated functional benefits in laying hens under the current study conditions, supporting its relevance as an alternative, supplementary choline source.