Effect of adding wood vinegar to drinking water on the growth performance, carcass characteristics and microflora populations of the small intestine in broiler chickens

Introduction: Wood vinegar (WV) is a liquid biomaterial that is produced by the thermo-pyrolysis process of woody biomass and it was defined as a reddish-brown aqueous liquid, it is a natural, nontoxic, safe, cheap and versatile product suitable for use as additive on animal diets, as preventive antibiotic and growth promoters. It has been shown to suppress bacteria, resulting in healthier poultry and increased yields. Therefore, this study aimed to determine the efficacy of drinking water supplemented with wood vinegar on growth performance, carcass quality, and microbial population parameters of broilers.
Materials and methods: A total of 540 one-day-old chicks (Ross-308) were used in a 42-day feeding trial. The experiment was conducted in a completely randomized design. There were six treatments with six replicates (15 chicks/replicate). The experimental treatments included were: 1) negative control (NC), (without wood vinegar in drinking water); 2) positive control (PC), (Commercial acidifier supplemented in drinking water); 3) 1.5 ml wood vinegar, in 1 liter drinking water; 4) 3.5 ml wood vinegar, in 1 liter drinking water; 5) 5.5 ml wood vinegar, in 1 liter drinking water; 6) 7.5 ml wood vinegar, in 1 liter drinking water. Experimental diets were formulated for three phases: starter, grower, and finisher. During the experimental period, average daily feed intake (ADFI), body weight gain (BWG), and feed conversion ratio (FCR) were measured. At the end of the experiment, two birds were selected from each replicate and slaughtered after weighing, and the weight of the internal organs (Breast, Thigh, Wing, Back, Heart, liver, Abdominal fat, Pancreas, Bursa of fabricius, Thymus, and Spleen) was measured. On days 21 and 42, two birds from each replicate were slaughtered to collect intestinal digesta and evaluate the intestinal microflora, First, dilution was performed and then it was spread linearly on the surface of plates containing culture. After the incubation period, the bacterial colonies were counted using a colony counter, and the results were expressed as log10 colony-forming units per gram of sample. The MRS agar plates were incubated anaerobically at 39◦C for 24-48 hours, while the MacConkey agar plates were incubated aerobically at 39◦C for the same duration to ensure optimal growth conditions for Enterobacteriaceae. Data were analyzed using the general linear model (GLM), and treatment means were compared using Tukey's test at P<0.05.
Results and discussion: No significant differences (p>0.05) were found, feed intake between groups during the starter (1- 10 days old), grower (11-24 days old), Finisher (25-42) and whole (1-42 days old) periods. It can be concluded that adding wood vinegar to drinking water has no significant effect on the feed consumption of broiler chickens. This suggests that wood vinegar does not contribute nutritionally (e.g., by providing energy, protein, vitamins, or minerals) to the diet. Instead, its potential benefits may stem from the general properties of its organic compounds, which could enhance gastrointestinal health and immune function. Daily weight gain and feed conversion ratio in the initial and final periods were not affected by the experimental treatments. During the growth and whole periods, treatment containing 3.5 ml of wood vinegar improved weight gain compared to the negative control treatment (P<0.05). The use of wood vinegar in treatments containing 3.5 and 5.5 ml of wood vinegar without any negative effect on carcass characteristics, breast, and thigh weights increased bursa of fabricius weight and decreased abdominal fat (P<0.05). The bursa of fabricius has an essential role in poultry immune system. The increased weight of the bursa of fabricius in wood vinegar-consuming treatments probably indicates an improvement in their immune system. The performance of poultry is significantly influenced by the health and safety status. A weak immune system causes weight loss when exposed to infectious diseases, so the use of immunostimulants can enhance performance by improving immune status. The population of Lactobacillus showed a significant increase (P < 0.05) at 21 days of age in treatments containing 3.5 and 5.5 mL of wood vinegar, as well as at 42 days of age in treatments containing 3.5, 5.5, and 7.5 mL of wood vinegar compared to the negative control. The count of Colibacillus bacteria exhibited a significant decrease (P < 0.05) at 21 days of age in treatments supplemented with 3.5 and 7.5 mL of wood vinegar relative to the negative control group. The use of wood vinegar in poultry drinking water improved microbial population by increasing the number of lactobacilli and reducing the population of Colibacillus bacteria, and improves the growth efficiency of broiler chickens.
Conclusions: In summary, the results of this research showed that adding 3.5 ml of wood vinegar to one liter of drinking water could improve growth performance and intestinal microflora in broiler chickens.