Can Pre-Fermented Juice Be an Alternative Probiotic Helping to Reduce Heat Stress in Laying Japanese Quails (Metabolism and Nutrition)

This study aimed to determine the effects of incorporating probiotic fermented natural lactic acid bacteria (PFJ) into the drinking water of laying quails subjected to temperature stress on egg production, egg quality, cecum microbiology, blood parameters, and incubation performance. A total of 260 Japanese quails (Coturnixcoturnix japonica) aged 8 weeks were used, of which 200 were females, and 60 were males. The quails were divided into four groups, each containing 50 individuals, and further split into five subgroups of 10 quails. For every 10 female quails, three male quails were housed together in cages. The experiment was conducted under normal environmental conditions in control, PFJ, heat-stressed control, and heat-stressed PFJ groups. Temperature stress (34–36 °C) was applied for 8 h daily. The results indicated that by the end of weeks 1–4, the feed conversion ratios of all groups were significantly different, with the best feed conversion ratio of 2.36 found in the PFJ group under temperature stress. Throughout the periods of weeks 1–4 and 5–8, there were statistically significant differences (p < 0.01) in the daily average feed consumption and egg weights among all treated groups. Temperature stress and the addition of PFJ significantly affected shell thickness, Haugh units, albumen weight, yolk weight, and yolk color; no significant impacts were observed on egg shape index, yolk percentage (%), albumen percentage (%), and specific gravity (g/cm3). The highest counts of lactic acid bacteria (LAB) were found in the PFJ-treated groups under both normal and temperature-stressed conditions. Under temperature stress, the levels of Enterobacter, coliform, and E. coli decreased with the addition of PFJ. Regarding blood parameters, significant differences (p < 0.05) were observed in total protein values among groups, while differences in chloride, triglycerides, total cholesterol, LDL cholesterol, HDL cholesterol, and triglyceride concentrations were not statistically significant (p > 0.05). Furthermore, the addition of temperature stress and PFJ significantly affected fertility rates, incubation efficiency, and hatchability. In conclusion, these findings suggest that PFJ could be considered a potential probiotic alternative for improving nutrition in laying quails under conditions of temperature stress.