جستجوی مقالات مرتبط با کلیدواژه "میکروبیولوژی" در نشریات گروه "علوم دام"

With the increase of the population in the last century, the need for protein sources, especially protein with animal origin, has increased. One of the important and inexpensive sources of animal proteins is poultry products. However, many food-borne diseases that are among the most obvious problems related to human health are transmitted to humans through poultry products. Generally, poultry are sensitive to pathogenic bacteria such as Clostridium, Salmonella, and Campylobacter. Campylobacter jejuni and Campylobacter coli are the main causes of bacterial enteritis in humans and account for about 90% and less than 10% of deaths in people with campylobacteriosis, respectively. Poultry farmers use antibiotic growth promoters to prevent the colonization of pathogenic bacteria, but their use has been banned in European Union since 2006 due to antibiotic resistance. However, in order to prevent the reduction of growth performance and mortality caused by the colonization of pathogenic bacteria in the gastrointestinal tract, it is necessary to introduce suitable alternatives. The antimicrobial potential of several medicinal plants, some plant-derived bioactive compoundsas well as some organic acids against a suspension of two Campylobacter serotypes (including 8 strains of C. jejuni and 3 strains of C. coli) has been investigated, under in vitro study. It has been revealed that oregano, rosemary, and cinnamon have a higher potential in reducing campylobacter colonization, among other phytobiotic compounds. Considering that under in vivo conditions, no research has been conducted on these medicinal plants with broiler chickens exposed to Campylobacter colonization. Therefore, this research was conducted with the aim of investigating the growth performance, excreta microbiota, intestinal morphology, and nutrient digestibility of broiler chickens challenged with C. jejuni and evaluating the potential of oregano, rosemary, and cinnamon in reducing the negative effects of this pathogen.

A total of 192 one-day-old chicks were randomly allocated to 6 dietary treatments in a completely randomized design with 4 replicates of 8 birds. The dietary treatments were as follows: 1-negative control (NC; basal diet without additive and without of C. jejuni); 2-positive control (PC; basal diet without additives but challenged with C. jejuni); 3-basal diet + Erythromycin (55 mg/kg); 4-basal diet + oregano powder (3 g/kg); 5- basal diet + rosemary powder (3 g/kg) and 6-basal diet+cinnamon powder (3 g/kg). All chickens were orally gavaged once a day with a suspension of C. jejuni live culture (2×108 cfu/mL, 1 mL/bird) on days 21 to 25, with the exception of those fed the NC. Throughout the experimental period, the birds were fed ad libitum and had free access to water.

The results showed that the C. jejuni, while weakening performance during the growth period, caused an increase in campylobacter colonization and a decrease in lactobacilli counts of the excreta (P<0.05). The reason for the improvement of the microflora can be due to the presence of antibacterial compounds such as thymol, carvacrol, verbenone, and cinnamaldehyde in the composition of the mentioned medicinal plants. Campylobacter jejuni also decreased the digestibility of organic matter and led to a decrease in villous height, villous height to crypt depth ratio, and villi surface area in the jejunum (P<0.05). The reason for the improvement of the intestinal morphology by herbal additives can be due to the improvement of the microflora of the digestive tract. All the negative effects arising from C. jejuni were alleviated by dietary treatments containing feed additives (P<0.05).

In general, it can be concluded that oregano and rosemary have the potential to reduce the pathogenic effects of Campylobacter jejuni and can be used as suitable alternatives to antibiotics in feeding broilers.

The effect of sweet wormwood essence (SWE) and Lactobacillus acidophilus on performance, ileal microbiology, ileal morphology and ileal nutrient digestibility of laying Japanese quails was investigated in 180 46-d-old female Japanese quail that were randomly allocated to 4 dietary treatments in a completely random design with 4 replicates and 9 birds per each. The experimental diets were as follows: basal diet as control group (without additive), basal diet plus Oxytetracycline (200mg/kg), basal diet plus SWE (250mg/kg), and basal diet plus lactobacillus acidophilus (4 cfu per kg diet). Results showed that the use of Lactobacillus acidophilus increased the egg mass per hen-housed compared to control and SWE treatments (P<0.05). The number of lactobacilli in the ileal digest was also significantly increased by Lactobacillus acidophilus and SWE treatments, when compared with control treatment (P<0.05). In addition, birds fed with diets containing Lactobacillus acidophilus and Oxytetracycline showed a significant increase in villous height and villous height:crypt depth, when compared with those on the control diet (P<0.05). It can be concluded that the use of Lactobacillus acidophilus as an alternative to antibiotics is more appropriate than SWE.