Evaluation of the toxicity of selenium from hydroponically produced selenium-enriched kale sprout in laying hens

Hydroponically produced Se-enriched kale sprouts (HPSeKS) are studied for their use as an alternative dietary Se supplement for poultry. The study experimented with different levels and sources of Se to determine toxicity and how the toxicity may affect productive performance, Se concentration in egg and tissues, and physiological responses of laying hens. One-hundred and twenty hens, 59 weeks of age, were divided into 5 groups. Each group consisted of 4 replicates and each replicate had 6 birds according to a 2 × 2 + 1 Augmented Factorial Experiment in a Completely Randomized Design. The experiment was conducted over a 4 week period, and 5 dietary treatments (T) were used: T1 basal diet, T2 and T3 basal diet plus 5 and 10 mg Se/kg from sodium selenite (SS), T4 and T5 basal diet plus 5 and 10 mg Se/kg from HPSeKS, respectively. The results make clear that Se from HPSeKS, at 5-10 mg/kg, did not affect (P > 0.05) feed intake and egg production; however, Se bioavailability decreased (P < 0.05). Egg, tissue and plasma Se concentrations, and GSH-Px activity in red blood cells increased (P < 0.05) compared to those in T1. Final body weight, feed intake, Se bioavailability, concentration of Se in breast muscle and plasma of hens fed Se from SS were lower (P < 0.05) than those of hens fed Se from HPSeKS. The findings demonstrate that dietary Se from HPSeKS at 5-10 mg/kg is not considered a toxic level for laying hens. The toxicity of Se from HPSeKS was less than the toxicity of Se from SS.