نوع مقاله : مقاله پژوهشی
نویسندگان
1 گروه علوم دامی، دانشکده کشاورزی، دانشگاه فردوسی مشهد، مشهد، ایران
2 گروه علوم دامی، دانشکده کشاورزی، دانشگاه لغمان، افغانستان
چکیده
کلیدواژه‌ها
موضوعات
عنوان مقاله [English]
نویسندگان [English]
Introduction Poultry industry is one of the biggest growing parts worldwide of the animal production economy. Japanese quails have recently attracted attention in the poultry sector for being a viable animal production economy with expected to reach about 4% higher in 2020 to a record 103.5 million tons (Chattopadhyay, 2014; USDA, 2019). Years ago, antibiotics were used at sub-therapeutic levels in diets to enhance poultry performance (Ronquillo & Hernandez, 2017). However, it has caused residues in feed and environment and hence a bacterial resistant in animals and human. Thus, medical alarms motivated on the complete removal of the antibiotics from animal feed (Mehdi et al., 2018). Thus, there is a need to find substances capable of replacing antibiotic growth promoters in the diets. The aim of these alternatives is to enhance performance while protecting environment and animal health (Ogbuewu et al., 2019) Thus, probiotics like yeast S. cerevisiae have been investigated as a feed additive for improve animal performance and health(Al-Khalaifah, 2018). Probiotics are live microorganisms that improve animals’ health by competing with undesirable microorganisms, improve intestinal microbial balance and absorption of nutrients (Duarte et al., 2012). Saccharomyces cerevisiae (also known as ‘baker’s yeast’) is considered as one of the most yeast species that are added to dietary formulations in poultry diets (Elghandour et al., 2020).
Saccharomyces cerevisiae contain substantial levels of digestible proteins, vitamins, magnesium, zinc and its wall have many characteristics such as polysaccharides α‐D‐mannan, chitin and β‐D‐glucan (Alizadeh et al., 2016) which play an important role in microbial balance in intestine towards beneficial organisms. Furthermore, proliferation of tissues in intestine and lymphocytes with a rapid cell turnover depend mostly on dietary nucleotides where de novo synthesis of nucleotides cannot meet their demand (Council, 1994).
Materials and Methods This experiment was conducted in order to investigate the effect of different levels of Chitacell commercial yeast on performance, carcass characteristics, intestinal morphology and blood parameters in the form of a completely randomized design with 7 treatments, 6 replications and 12 chicken in each experimental unit and a total of 504 chicken. One day Japanese quail mixed of two sexes was performed. At the end of the experiment (d 35), 2 Japanese quails from each replicate were weighed and slaughtered. Visceral and lymphoid organs were also weighed and recorded. About 8g of the contents from duodenum, jejunum and ileum were collected in 80 mL physiological saline for pH value measurement. Blood samples were collected from the same Japanese quails used for carcass traits and were centrifuged at 3000 rpm for 10 min, then stored for later analysis at -20°C. order to measure E. coli and C. Perfringens bacteria in feces, standard plate counting method was used. And also Duodenum specimens were collected and fixed in 10% neutral buffered formalin solution for 24 h, then embedded in paraffin and sectioned at 4 μm. The following parameters were measured: (i) villous height (VH), (ii) depth of crypt (CD) and (iii) ratios of VH/CD
Results and discussion According to the results of this study show that experimental treatments had no significant effect on feed consumption (P<0.05). But on the contrary, the group fed with 0.75, 1, 1.25 and 1.5 percent of Chitacel commercial yeast could significantly increase the weight gain compared to the control group (P<0.05). Also, the food conversion factor decreased significantly with increasing the amount of Chitacel commercial yeast in the diet (P<0.05). According to the results of this experiment, it has been reported that live yeast has a favorable effect on the feed conversion factor and final weight gain in broiler chickens (Smith et al., 2014). In addition, it has been reported in another study that the use of yeast for 5 weeks in feeding broilers increases live weight (Pourabedin et al., 2014). Also, the results show that experimental treatments had significant effects on blood serum parameters (P<0.05). But it had no significant effect on liver enzymes compared to the control group (P<0.05). On the other hand, cholesterol and triglycerides in the blood decreased significantly by adding different levels of commercial chitacel yeast (P<0.05). According to the results of this experiment, it has been reported that feeding Japanese quail with yeast supplements leads to a decrease in serum cholesterol in the blood (Aluwong et al., 2013). On the other hand, interleukin 1 and 6, as well as tumor necrosis factor alpha decreased significantly (P<0.05) with the increase in the level of Chitacell commercial yeast in the diet. Similar to this experiment, it has been shown that the oxidative defense mechanisms can be stimulated by mannan-oligosaccharides and β-glucans, which are part of Saccharomyces cerevisiae, this indicates that dietary yeast can, instead of removing undesirable bacteria, from protect the intestine (Jacob & Pescatore, 2017). It has also been reported that superoxide dismutase and catalase are the main antioxidant enzymes that form the first line of antioxidant enzyme defense (Bolacali & İrak, 2017). The results of the present study showed that live yeast at different levels can significantly prevent the increase of serum IL-1β, IL-6 and TNF-α compared to the control group. This could indicate that in the absence of an immune challenge or infectious pathogens, yeast-fed Japanese quails may not show inflammatory responses, which is consistent with the results of (Alizadeh et al., 2016).
Conclusion The results of this study showed that the addition of Chitacell commercial yeast can have beneficial effects in Japanese quail broilers. Different levels of yeast were able to improve total weight gain and also reduce food conversion ratio compared to the control group. Yeast also reduced the percentage of abdominal fat and increased the size of the thymus. The number of Clostridium perfringens and E-coli bacteria decreased significantly in the feces of chickens fed with Chitacell commercial yeast. In general, according to the results obtained from this research, it can be said that the use of Chitacel commercial yeast has favorable effects, and according to the results, it can be said that the best level used is 0.75 kg per ton of feed.
کلیدواژه‌ها [English]
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