| چکیده انگلیسی مقاله |
Extended Abstract
Introduction and Objectives: In the poultry industry, additives are used to stimulate growth, improve production performance, and also improve the health of the flock. On the other hand, reducing the quality of food items and their protein level, as well as the high level of anti-nutritional substances, cause the disturbance of the balance of the microbial ecosystem of the digestive system of birds, health and ultimately reduce their performance. The health and nutritional status of poultry is largely dependent on the microbial flora of the digestive system, which directly and indirectly affects the morphology of the digestive system, nutrition, and immune system. The microbial flora of the intestine is relatively unstable and is easily affected by various nutritional factors. Therefore, the aim of this research was to investigate the effect of the simultaneous use of organic acids and prebiotics in diets containing low-quality soybean meal on the performance of laying hens.
Material and Methods: This experiment was conducted using a completely randomized design in a 2x2 factorial arrangement using Two levels of mixed organic acids and prebiotics and two types of soybean meal in diet of laying hens. Chickens were distributed among pens based on weight and production rate for two weeks. 192 laying hens of LSL strain at the end of 73 weeks of age, after weighing and entering the wing number, were placed in 48 experimental cages including 4 treatments with 12 replications, and fed for 12 weeks. Experimental treatments include treatment one (without the combination of organic acids and probiotics and containing soy 42% protein), treatment two (without the combination of organic acids and probiotics and containing soy 38% protein), treatment three (containing the combination of organic acids and probiotics and containing soy 42 percentage of protein), treatment four (contains a combination of organic acids and probiotics and contains soy 38% protein). To add the combination of organic acids and prebiotics, organic acid was used in the consumption amount of 1 kg per ton. The composition of the product included 30% propionic acid, 10% butyric acid, 15% acetate plus 20% prebiotic with the origin of Saccharomyces cerevisiae yeast cell wall. Performance traits including production percentage and egg weight, egg mass weight and feed conversion ratio at the end of the experiment (age 85 weeks), all the birds were killed using the cervical vertebrae displacement method. parameters of the abdominal fat response of the immune system, histomorphology of small intestine and microbial population of cecum were investigated.
Results: Except for the first week of the experiment, during the rest of the experiment, the addition of the combination of organic acids and probiotics and the use of high-quality soybean meal in the ration caused a significant increase in egg-laying percentage (P<0.01). In the first 4 weeks of the experiment (weeks 75 to 78), the percentage of egg production was under the significant influence of the mutual effects of the experimental factors, so the treatment with organic acids and prebiotics and high-quality soybean meal (treatment 3) had the highest amount of egg production (P< 0.05). From the second week to the end of the experiment, the consumption of diets containing the combination of organic acids and probiotics and high-quality soybeam meal significantly increased the weight of the produced eggs (P<0.05). The mutual effects of experimental treatments during the experimental period did not show a constant trend in the weight of produced eggs (P≥0.05). Adding the combination of organic acids and probiotics to the diet caused an increase in egg mass in the entire experimental period, the difference of which was significant (P<0.05). The use of soybean meal with low protein soybean meal in the diet during the experimental period caused a decrease in the weight of the egg mass compared to the group consuming the diet containing high-quality soybean meal (P<0.05). Adding the combination of organic acids and probiotics as well as the use of high-quality soybean meal in the diet of the studied laying hens improved the conversion rate during the test period (P<0.05). The feed conversion ratio in the first 5 weeks of the experiment was under the mutual effects of experimental factors. (P<0.05). Abdominal fat at the beginning of the experiment (age 73 weeks) and at the end of the experiment (age 85 weeks) did not show any significant difference between different treatments (P≥0.05). Cellular immune response to DNCB injection significantly increased with the use of organic acids and prebiotic mixture and decreased with the presence of low-protein soybean meal in the diet (P<0.05). The microbial population of cecum changed significantly under the influence of the mutual effects of the mixture of organic acids and prebiotics and the quality of the feed soup (P<0.05). The use of a mixture of organic acids and prebiotics caused a significant increase in the height of the duodenal villi (P<0.05). The presence of low-protein soybean meal in the diet caused a significant increase in depth of crypts (P<0.05). The use of a mixture of organic acids and prebiotics caused a significant increase in the height of duodenal villi (P<0.05). The presence of low protein soy in the diet caused a significant increase in the depth of crypts (P<0.05). The ratio of villus height to crypt depth changed under the significant influence of the mutual effects of the experimental factors, so that the treatment with a mixture of organic acids and prebiotics and high-quality soybeans in the feed had the highest ratio, and the treatment without a mixture of organic acids and prebiotics and low-protein soybeans in the feed had the lowest villus height ratio. as deep as the crypt (P<0.05). The width of duodenal villi did not change under the influence of experimental factors and no significant difference was observed (P≥0.05).
Conclusion: In general, the results showed that use of combination of organic acids and probiotics in the diet of laying hens improved their productive performance and the health of their digestive system. Also, use of combination of organic acids and probiotics improved performance of chickens fed with low-protein soybean meal.
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