اثر افزودنی های گیاهی تجاری کوکسان، اوایکس پلنت و انتکس در آب و خوراک بر عملکرد رشد، ریخت شناسی و میکروفلور روده و پاسخ ایمنی جوجه های گوشتی

Introduction: It has been demonstrated that medicinal plants and their derivatives can improve various aspects of broiler chicken production, including feed consumption, daily weight, feed conversion ratio, gut health, and immune responses. Using multiple medicinal plants in combination may enhance synergistic effects, improving broiler chicken performance and carcass quality compared to using individual plants. In broiler chicken farming, feed additives are often added to drinking water where pelleted diets are prevalent. Therefore, adding feed additives to either feed or drinking water raises serious questions regarding their efficacy. Three commercial phytogenic feed additives that are available in the market are Coxan, O.X.Plant, and Entex. Coxan contains oregano (with menthol as the active ingredient) and garlic (containing allin and allicin), O.X.Plant contains savory (the active ingredient carvacrol and thymol), thyme (with thymol and carvacrol as the main active ingredients) and red pepper oleoresin ( with capsaicin) and Entex contains cinnamon (cinnamaldehyde), garlic and eucalyptus (cineol). The objective of this research was to compare the effects of implementing these commercial phytogenic feed additives (in water and feed) on growth performance, intestinal microflora and morphology, and immune response of broilers.
Materials and methods: A total of 336 Ross 308 broilers were examined in a completely randomized design with seven treatments, four replicates, and 12 chickens per replicate. Experimental treatments included: control (without phytogenic in feed or water), Coxan either in feed (300 mg/kg) or in drinking water (200 mL/1000 L), O.X.Plant either in feed (200 mg/kg) or in drinking water (135 mL/1000 L) and Entex either in feed (500 mg/kg) or drinking water (350 mL/1000 L). Daily weight gain, daily feed intake, daily water intake, and feed conversion ratio were measured throughout the experiment. After slaughtering broilers at 42 days of age, the length of each intestinal section (duodenum, jejunum, ileum) was measured for two broilers from each experimental unit. To determine the microbial population, samples were taken from the ileum of chickens. EMB culture medium was used to determine Escherichia coli population and MRS culture medium was used for Lactobacillus bacteria. To check the humoral immune response, 0.1 mL of 25% sheep red blood cell suspension in PBS was injected into the breast muscle of chickens on days 12^th and 29^th of rearing. Blood samples were taken from the chickens on days 28, 35, and 42 of rearing, and the titers for anti-SRBC, immunoglobulin G, and M were determined. Antibody titer against Newcastle disease was measured by the HI method.
Results and discussion: The effect of phytogenic additives in feed or drinking water on average daily feed consumption, daily weight gain, feed conversion ratio, and daily water consumption was not significant in the entire rearing period. Broiler chickens' water intake did not change, indicating that the additives added to their drinking water at tested levels do not have an unpleasant taste that would deter the chickens from drinking it. The relative lengths of the duodenum, jejunum, cecum, and colon were not affected by the experimental treatments. However, chickens that received Entex in their feed exhibited a lower relative length of the ileum compared to the control group.  No significant difference was observed in the relative length of different sections of the intestine in the birds that received phytogenic additives either in feed or water. The relative lengths of the duodenum, jejunum, cecum, colon, villus length, villus area, crypt depth, thickness of lamina propria, thickness of muscular layer, and thickness of advantis layer were not affected by the experimental treatments.  Chickens consumed 500 mg/kg of Entex phytogenic additive in the feed had a lower villus width in the ileum region compared to the chickens in the control group. The population of Escherichia coli in the ileum decreased by adding O.X.Plant and Entex to the broiler feed, compared to the control group.  Broilers fed Entex in the feed had also a lower count of Escherichia coli compared to those fed Coxan in the diet. The population of Lactobacillus bacteria in the ileum of chickens that received Coxan in water, O.X.Plant in feed and water, and Entex in feed increased compared to the control group. There was no significant difference in the population of Escherichia coli and Lactobacillus bacteria in the treatments that received phytogenic additives either in feed or in drinking water. The addition of phytogenic essential oils in poultry feed has been shown to improve the microflora by increasing the number of lactobacilli, which may also improve the morphological characteristics of the intestine, probably improving the ability of digestion and absorption in the digestive system and growth efficiency of broiler chickens. Antibody levels against SRBC were higher at 28, 35, and 42 days in all chickens consuming phytogenic additives in drinking water. The performance of animals is directly linked to their health and immunity. A compromised or stressed immune system not only makes animals susceptible to infectious diseases but can also lead to weight loss.  when dealing with infectious diseases. Therefore, the use of immunomodulators can increase performance by improving the immune status. In poultry production, it is important to strengthen the immune system to prevent the occurrence of diseases.
Conclusions: The results of this research showed that the commercial phytogenic additives Coxan, O.X.Plant, and Entex did not have significant effects on growth performance, relative length, and intestinal morphology in broilers. However, a notable finding was the significant reduction in the population of pathogenic Escherichia coli with the addition of O.X.Plant and Entex in the diet compared to the control group. In general, it can be concluded that adding the tested phytogenic additives in water not only does not hurt the drinking water consumption of broilers but also the immune responses of broilers were found to be more positively improved when these phytogenic additives were administered in water compared to adding them in feed. This suggests that leveraging these additives in water may offer enhanced benefits in terms of improving the immune system in broilers without compromising performance parameters.