The effect of glibenclamide on performance, carcass characteristics, blood parameters, immunity, intestinal microbial flora, intestinal morphology and breast muscle fatty acid profile in broilers

Glibenclamide, with IUPAC name chloro-N-(4-[N-(cyclohexylcarbamoyl) sulfamoyl] phenethyl)-2-methoxybenzamide, is a sulfonylurea derivative with a melting point of 169-174 ◦C. This substance is in the form of a white crystalline powder, often without smell and taste, insoluble in water but soluble in methylene chloride. Glibenclamide is classified as sulfonylurea drugs which act by stimulating beta cells of the pancreas to secrete more insulin throught increased intercellular cAMP. These drugs are only effective in people who have minimal ability to secrete insulin. At the same time, these drugs have been suggested to increase the binding of insulin to receptors and increase the number of insulin receptors (Rambiritch et al., 2007). Recent studies have reported that glibenclamide also plays a role in the hypoglycemic effects in the regulation of inflammation. No data are available regarding the effect of glibenclamide in broilers and whether glibenclamide can have an effect on performance, carcass characteristics, blood parameters, immunity, intestinal microbial flora, intestinal morphology, and fatty acid profile and not clear whether it is benefit in chicken or not and it needs further investigation. This research was conducted in 2022 at a broiler farm located in Rasht. The trial utilized 120 one-day-old broiler chickens of the commercial strain Ross 308 with an average weight of 43±1g. The experiment was conducted as a completely randomized design with 3 treatments and 4 replications of 10 chickens per pen for 42 days. Experimental treatments include three dietary concentrations of glibenclamide: 0 (Control), 75, or 100 mg/kg glibenclamide). The ration was formulated to meet the minimum nutritional requirements of the Ross 308 strain. Chickens were reared in 1×1 m cages on a bed of cellulose rolls for 42 days. The weight gain of all chickens in each pen was calculated by a digital scale with an accuracy of ±10 g during periods of 1 to 10, 11 to 21, and 22 to 42 d. At the end of each period, the amount of remaining feed (beginning 1 to 10, growth 11 to 21 and ending 22 to 42) at the beginning of each period, the amount of feed consumed was calculated by weighing in each feeder and deducting from the amount of feed given. Also, feed conversion was calculated by dividing the amount of feed consumption by the weight gain for days 1 to 10, 11 to 21, and 22 to 42 and the entire period. Economic efficiency, carcass characteristics, digestive organs, blood parameters, immune responses, intestinal microbial flora, intestinal morphology, and breast fatty acid profile were measured. All data collected during the experiment and laboratory traits were analyzed by analyses of variance using statistical software. Means were compared with Duncan's multiple range test at 5% statistical levels. The results indicate that during all of the growing periods, the use of glibenclamide did not affect the performance of broiler chickens (P≥0.05). Also, weight at 42 d of age, feed cost per kg live weight (Rial/kg), and European index were not different among dietary concentrations of glibenclamide (P≥0.05). Use of two different levels of glibenclamide did not have a difference on live weight, featherless weight, thigh percentage, breast percentage and abdominal fat (P≥0.05), but 75 mg/kg was reported to reduce fat in the ventricular area. Glibenclamide did not affect blood glucose concentrations (P>0.05). Feeding 0 or 75 mg/kg of glibenclamide as a sulfonylurea derivative reduced cholesterol, triglycerides, HDL, VLDL and LDL concentrations (P<0.05). The LDL to HDL ratio was highest for 75 compared with 0 and 100 mg/kg glibenclamide (P<0.05). In contrast, concentrations of total protein, albumin and globulin were greatest for 0 mg/kg, intermediate for 75 mg/kg and highest for 100 mg/kg (P<0.05). No differences were observed among treatments on humoral immune system function in response to SRBC antigen injection, except for 35 d which was highest for 100 mg/kg glibenclamide, and antibody titer against Newcastle virus and influenza (Table 7). In response to SRBC antigen injection, Newcastle and influenza titers increased at the end of the course. Feeding glibenclamide did not increase the relative weight of the bursa of Fabricius or the weight of the spleen (P≥0.05). Feeding 0 or 75 mg/kg glibenclamide supported lower numbers of Escherichia coli bacteria compared to other treatments (P<0.05); however, no differences were observed in the number of Lactobacillus acidophilus. The highest villi length was observed with the consumption of 75 mg/kg glibenclamide. The depth of the crypt increased in the same dose of glibenclamide compared to the control group, but the ratio of villi length to the depth of the crypt decreased. The results indicate that lower percentages of myristic and palmitic acid were observed when 75 mg/kg of glibenclamide was fed compared with 100 mg/kg; however, palmitoleic, steric, oleic, linoleic, and linolenic acid percentages were lowest and the ratio of saturated to unsaturated fatty acids was highest when 100 kg/kg of glibenclamide was fed. In general, the results of this trial indicate that glibenclamide does not improved feed consumption, weight gain, conversion rate, total cost per kilogram of live chicken and production index in the rearing period. However, feeding low concentrations could reduce abdominal fat. Feeding low concentrations of glibenclamide led to a positive effect on blood factors, including triglycerides, cholesterol, VLDL, LDL, total protein. Populations of Escherichia coli were reduced in the intestine which appeared to improve villi length and crypt depth as well as the ratio of villi length to crypt depth compared to the control group. In comparison of saturated and unsaturated fatty acids, its low dose was able to reduce the ratio of saturated to unsaturated fatty acids. Therefore, according to the positive effects of glibenclamide on performance, carcass characteristics, blood parameters, immunity, intestinal flora, intestinal morphology and fatty acid profile, this food additive can be used as an alternative to commercial antibiotics and a cheap growth promoter.