Effects of Fennel and Ginger Extract Supplementation on Reproductive Performance, Serum Biochemistry, and Histology Traits of Testis in Japanese Quails

Background: Oxidative stress is caused by excessive levels of reactive oxygen species under stressful environmental conditions.Today, oxidative stress is considered one of the main negative factors affecting the performance of birds in the concentrated poultry industry.Oxidative stress is a major factor in the pathogenesis of several serious diseases in poultry.Therefore, supplementing diets with artificial antioxidants (for example, -tocopheryl acetate or butyl hydroxytoluene) has become a common practice to reduce oxidative stress.Recently, the use of plant extracts as natural antioxidants has received increasing attention due to the global trend of limiting the use of artificial substances.The plant extracts rich in antioxidants include fennel and ginger, which have good potential to improve reproductive performance.Therefore, this study was conducted to investigate the effects of diets supplemented with fennel and ginger extracts on reproductive performance, serum biochemistry, and testis histology in Japanese quail.Methods: A total of 72 Japanese quail birds (60 female and 12 male birds) at the age of 8 weeks were used for this study.The birds were randomly divided among four experimental groups.Each group was divided into four replicates, each with six birds in a completely random design.Group 1 received a basic diet without additives and was considered the control group.Groups 2 and 3 received the basic diet with 350 mg/kg of aqueous-alcoholic extracts of fennel and ginger, respectively.The percentage of egg production was recorded and calculated by the hen-day method.A total number of 252 unbroken quail eggs were collected during the last week of the experiment and used to evaluate reproductive performance.The eggs were incubated in a normal incubator with suitable conditions (37.5 C and 60% relative humidity), followed by calculating the fertility and hatchability.The level of MDA in blood serum and thigh muscle as an index of lipid peroxidation was determined by the thiobarbituric acid reaction test.Blood testosterone concentration and the function of testicular tissue were determined as well.For testicular histological evaluation and spermatogenic analyses, all male quails were killed on the last day of the experiment.The left testicles were kept in 10% formalin solution for further evaluation.Testicular tissue samples were cut using a microtome (Leica Junc Histocut 820) to a thickness of 7 micrometers and placed on a slide.The stained sections were observed with 400 magnification of an optical microscope (Olympus CX22) and analyzed morphometrically using a computerized image analysis system (Olympus Soft Image Solution GmbH).The obtained data were analyzed using the GLM procedure of SAS statistical software.Results: The egg weight and Hugh units significantly increased in the birds receiving the diet supplemented with fennel compared to the control group (P < 0.05).The fertility rate in birds fed with fennel and ginger extract showed a significant increase in comparison with the control group.High hatchability (relative to total incubated eggs) was observed in the ginger group compared to the control group (P = 0.014).Total cholesterol and triglyceride of serum decreased significantly in birds fed with the diet containing plant extracts (p = 0.006), but no change occurred in the concentrations of HDL, LDL, and blood alkaline phosphatase (P > 0.05).Hepatic transaminases AST, ALT, and the AST/ALT ratio, as indicators of liver cell damage, were not affected by fennel extract, but ginger extract treatment caused a decrease in ALT in comparison with the control