Soya saponin improves egg-laying performance and immune function of laying hens

BACKGROUND

Soya saponin (SS), an active compound in soybean meals, has been widely studied in the medical field. However, it was considered as an anti-nutritional factor in poultry diets. The objective of this experiment was to measure the effects of dietary SS using three dietary treatments on egg-laying performance and immune function of laying hens. Birds were fed a low soybean meal basal diet (CON), a low-SS diet (50 SS) containing 50 mg/kg SS, or a high-SS diet (500 SS) containing 500 mg/kg SS for 10 weeks. At the end of the 5th and 10th week of the trial, samples were collected for analysis.

RESULTS

Results showed that with 50 mg/kg SS supplementation, the egg production rate, feed conversion ratio (FCR), and eggshell quality tended to be improved. Serum follicle stimulating hormone (FSH) and Interleukin-4 (IL-4) levels were also elevated as well as the peripheral blood LPS stimulation index, the proportion of B lymphocytes, and antibody titer of bovine serum albumin (BSA). We also found that mRNA levels of follicle stimulating hormone receptor (FSHR) in ovarian, nuclear transcription factor kappa B (NF-κB), Transforming growth factor (TGF-β) and interferon γ (IFN-γ) in spleen were up-regulated at the end of the trial. Additionally, dietary 50 mg/kg SS improved the ileal flora via up-regulating the relative abundance of Lactobacillus, Romboutsia and Lactobacillus delbrueckii. Although the immune related indicators were improved with 500 mg/kg SS supplemented, it seemed to have a negative influence on the laying-performance. Specifically, serum alanine aminotransferase (ALT), alkaline phosphatase (ALP), and the ratio of IFN-γ to IL-4 were increased in the 500 SS group at the end of the trial. The mRNA levels of gonadotropin releasing hormone 1 (GnRH1) in Hypothalamus, the estrogen related receptor (ERR) in ovaries were downregulated as well as the egg production rate during the trial with 500 mg/kg SS supplemented.

CONCLUSIONS

The egg production performance was improved by dietary supplemented with 50 mg/kg SS via increasing ovarian FSHR transcription level and serum estrogen level. A beneficial shift in intestinal microflora was recorded, and the immune function of laying hens was also improved with 50 mg/kg SS supplementation. Surprisingly, the long-term supplementation of 500 mg/kg SS exerted a negative impact on the laying performance and physiological functions of the liver of laying hens.

Effect of advanced chelate compounds-based mineral supplement in laying hen diet on the performance, egg quality, yolk mineral content, fatty acid composition, and oxidative status

The study aimed to determine the efficiency of advanced chelate compounds-based trace minerals (OTM) in laying hens. Laying hens (240, 32 weeks old) were assigned to one of the following five groups: NOTM (no added trace minerals), CONTM (standard mineral salts), and three experimental groups in which chelates were used to replace 33, 66, and 100% of mineral salts (OTM33, OTM66, and OTM100, respectively). Each treatment had six replicates with eight hens per replicate. After 18 weeks, performance and physicochemical properties of eggs in all experimental groups was better than those in the NOTM group. Among the treatments, OTM66 and OTM100 produced the best results in terms of laying performance, yolk PUFA/SFA ratio, Zn and Se contents, and malondialdehyde concentration in both serum and yolk. In conclusion, up to 66% OTM supplementation was beneficial for performance, lipid and mineral composition of yolk, and oxidative status.