Effects of Butyrate, Butyric Glycerides in Combination with Different Selenium Sources as Strategies to Improve Performance of the Aged Laying Hens

In recent years, the egg industry is aiming to prolong the life cycle of laying hens, both for reasons of profitability and for sustainability. However, the goal to produce 500 eggs in a 100-week cycle is hindered by the declining performance of older hens. It is hypothesised that nutritional strategies can be implemented to support the health of these animals, thereby improving laying persistency. The objective of this trial was to investigate the effects of two sources of butyrate (precision delivery-coated sodium butyrate and butyrate glycerides, Adisseo France) either with or without the addition of an organic selenium (OH-SeMet, Adisseo, France) on the performance of aged laying birds. 900 fortyfive-week-old Hy-Line brown hens with similar performance were randomly allocated to five treatment groups with 10 replicates of 18 animals each. The experiment lasted 20 weeks. The five experimental diets were based on commercial feeds supplemented with 0.3 mg/kg of sodium selenite (Control), and with 240 mg/kg butyric acid, either as coated butyrate (a 24% butyric acid product) (T2), or as butyric glycerides (a 40% butyric acid product) (T3). In treatments 4 and 5, 0.3 mg/kg of Se from OH-SeMet was used, combined with the coated butyrate (T4) or with the butyric glycerides (T5), both at 240 mg/kg butyric acid. Data was evaluated using a one-way analysis of variance (ANOVA). Significant differences were considered at p ≤ 0.05, and a Tukey test was used to compare separated means. Results showed that the supplementation with the different nutritional strategies supported laying performance in a T5 > T4 > T3 > T2 > Control trend (Figure 1a), with T4 and T5 performing significantly better than the Control. Compared to the Control group, the feed/egg weight ratio was improved by supplementation of butyrate-based products: we observed a numerical improvement for T2 and a significant difference in T3. This effect was further increased with the additional inclusion of OHSeMet in the diet, as shown on Figure 1b. No significant difference in performance was detected between the dietary butyrate treatments. However, as these two additives will release butyrate in different parts of the digestive tract, we speculate that distinct modes of action underly their beneficial effect on performance. In summary, this trial adds evidence to the potential of butyrate additives, alone or in combination with OH-SeMet, as effective nutritional strategies to support a longer laying cycle.