Effects of Adding Ferula badrakema Root Powder with and Without Sodium Saccharin Sweetener to the Diet on Growth Performance, Immune System and Blood Metabolites of Broiler Chickens

 The Ferula badrakema from the Apiaceae family is a resinous plant with a strong smell that is native to Iran (Rechinger et al., 1994). The anti-bacterial and anti-fungal properties of Ferula badrakema are believed to be due to its high content of alpha-pinene and beta-pinene. Similar to other Ferula species, this plant is a rich source of sesquiterpene coumarins (Bukreeva and Pimenov, 1991). To the best of our knowledge, no study has been done on the volatile compounds of this species. However, studies on other species of this plant that grow in other parts of the world have been reported (Başer et al., 2000; Takeoka, 2001, Iranshahi et al., 2006). Saccharin is a sulfonamide produced from compounds found in coal tar (Abdelaziz et al., 2011). Its taste is 300 to 500 times sweeter than sucrose. Due to its high sweetness, it is widely used to improve feed palatability and can increase feed intake (Feighner et al., 1987). Studies by Han et al. (2019) have shown that Japanese quails prefer sucrose solution instead of ordinary water due to its palatability. However, few studies have been conducted on the physiological relationship between sweeteners and the gastrointestinal tract of broilers (Kimmich et al., 1989). Considering that most medicinal plants have a bitter taste and reduce the feed consumption and growth of chickens, this experiment aimed to investigate the effects of adding sweeteners and preventing the activation of bitter taste receptors of the Ferula plant on the growth performance, immune system and blood metabolites of chickens. This experiment was conducted using 468 one-day-old commercial broilers from the Ross 308 strain with 6 treatments, 6 replicates and 13 birds each in a completely randomized design as a 3×2 factorial arrangement (3 levels of Ferula badrakema root powder at the levels of 0, 0.75 and 1.5% and two levels of 0 and 0.15% sodium saccharin in diet). Standard diets during the periods of starter (1-10 d), grower (11-24 d) and finisher (25-42 d) were used. The diets were formulated using the UFFDA software to provide all the requirements of the broilers based on the recommendations of the Ross 308 strain (2019). Throughout the experiment, the birds had ad libitum access to water and feed and an hour darkness and 23 hours of light was provided. The initial temperature of the room was 32°C, which was reduced by 0.5°C per day according to the Ross company guidelines, until it reached 21°C at the age of 21 days and remained constant after that. Average feed intake, weight gain and feed conversion ratio for each group were measured at the end of each period. To measure blood parameters, one male bird at the end of the experiment (42 d), was selected from each replicate and blood samples were taken from the wing vein in syringes without anticoagulant, and after centrifugation, the sera were collected in 0.5 ml microtubes and kept at -20°C until the further analysis. To evaluate the humoral immune response, 0.1 ml sheep red blood cells (SRBC) suspension was injected to breast muscle of one bird from each replicate on 28 and 35 d and total antibody, IgG and IgM were measured.  Adding saccharin to the diet caused a significant increase in feed intake during the periods of 1-10 and 1-42 days (P < 0.05). The interaction effect of saccharin and Ferula on feed intake was significant (P < 0.05) during the periods of 25-42 and 1-42 days; so the addition of Ferula to diets containing saccharin increased feed intake while in diets without saccharin, it reduced feed intake. The body weight gain of chicks at the age of 1-10, 42-25 and 1-42 days in the treatment with 0.15% saccharin was significantly (P < 0.05) higher than the treatment without saccharin; but adding Ferula had no significant effect on the weight gain. Addition of Ferula and saccharin to the diet and their interaction had no significant effect on the carcass traits of broilers. Adding saccharin to the diet caused a significant increase (P < 0.05) in blood uric acid, but it did not have a significant effect on the concentration of other blood metabolites. An independent comparison of Ferula supplemented diets with treatment without it, showed that Ferula caused a significant (P < 0.05) increase in blood uric acid, albumin and phosphorus and a significant decrease in blood cholesterol and triglyceride. The titer of total antibody and IgG at the age of 35 days, as well as IgG and IgM at the age of 42 days, increased compared to its 0 level under the influence of Ferula consumption. In general, the results showed that the use of sodium saccharin in the diet prevents the reduction of feed intake caused by the bitter taste of Ferula, and the consumption of Ferula improves the immune system and reduces the concentration of cholesterol and triglycerides in the blood broiler chicks.