Effect of a Diet Supplemented with the Moringa oleifera Seed Powder on the Performance, Egg Quality, and Gene Expression in Japanese Laying Quail under Heat-Stress

SIMPLE SUMMARY: The debilitating effect of heat stress on egg production is well known, but its mechanism is not understood. Some studies attribute for this bad effect on the reduction in feed intake to high temperature or the relation between heat stress and reproductive and ovarian dysfunction, which cause a lowering in egg production. Heat stress directly affects ovarian function by altering the secretion of ovarian hormones such as prolactin. Moringa seed powder plays an effective role in overcoming the effect of heat stress, through the flavonoids and other phenolic compounds present in it. Hence, we investigated the effect of feeding Moringa oleifera seed powder with different concentrations, on egg production, egg quality trait, and the expression levels of selected ovarian genes in quail layers subject to heat stress. We found that supplementing laying Japanese quail feed with the Moringa oleifera seed powder at level 0.3% enhanced resistance to heat stress condition and consequently improved egg productivity. ABSTRACT: This study was conducted to evaluate the effect of three concentrations of the Moringa oleifera seed powder as a feed supplement on the productive performance and egg quality traits of laying Japanese quail (Coturnix japonica) exposed to heat stress. The expression patterns of the genes estrogen receptors (ESR2), follicle-stimulating hormone receptor (FSHR), prolactin receptor (PRLR), and steroidogenic acute regulatory protein (STAR) were estimated in ovaries, using a quantitative real-time polymerase chain reaction. A total of 200 laying quail aged seven weeks were randomly allocated to the following four experimental groups—the control (CNT), T1, T2, and T3 groups; each group comprised 50 quail females with 5 replicates (10 per group). The CNT group was fed a basal diet, whereas the T1, T2, and T3 groups were fed the basal diet supplemented with 0.1%, 0.2%, and 0.3% M. oleifera seed powder, respectively. The results revealed that the T3 group showed the highest hen-day egg production (%) as well as the highest egg yolk index. Feed intake and feed conversion ratio improved significantly (p < 0.05) with increased concentrations of the M. oleifera seed powder supplementation. Furthermore, the mRNA expressions of ESR2, FSHR, and STAR increased significantly in the T3 group, compared to those in the CNT group. Alterations in ovarian gene expressions corresponded to the reproductive patterns of the treated Japanese quail. Thus, it was concluded that the supplementation of the Japanese quail feed with 0.3% M. oleifera seed powder during the laying period might enhance resistance to heat stress and consequently improve egg productivity.