Veterinary Research Forum

Abstract Crude fiber (CF) is a vital component in poultry nutrition with a notable phytonutrient effectively indicating the presence of indigestible biomass in food due to the absence of digestive enzymes for CF in broilers. This study aimed to analyze the properties of a multi-enzyme cocktail (MEC) Bacillus sonorensis BD92 (BsBD92) comprised of xylanase, β-glucosidase, exo-glucanase, and endo-glucanase enzymes. Also, this study intended to look at the growth performance and intestinal histology of broilers in the starter and finisher phases by the addition of MEC BsBD92 to their diet. To evaluate the efficacy of MEC BsBD92, 140 one-day-old unsexed Cobb500 broiler chicks were randomly divided into seven groups receiving different diets. The characterization of exo-glucanase, xylanase, β-glucosidase, and endo-glucanase showed that their peak activities were observed at a temperature of 50.00 ˚C and a pH of 5.50. The 6.00% CF and 2.00 X MEC BsBD92 improved the intestinal morphology and feed conversion ratio, demonstrating a synergistic effect on growth performance. Whereas, increasing meat percentages to 61.06 and 65.09 g per 100 g body weight during the starter and finisher phases was also observed, respectively. The lipid profiles revealed significant variations in triglyceride and cholesterol levels. This study provides an innovative approach, considering not only lowering the feed cost using inexpensive fibrous feedstuffs but also improving the feed efficiency through supplementation of MEC BsBD92.

Abstract Apelin is an endogenous peptide ligand for G protein coupled apelin receptors (APJ orphan receptors) which are very similar to angiotensin II receptors. Apelin is expressed in most tissues of the body including hypothalamus that is responsible for regulating water and food intake, the gastrointestinal tract, the circulatory system, adipose and muscle tissues, and the immune system. The physiological actions of apelin, including food intake, has not yet been reported in birds. In this study, the effect of intracerebroventricular injection of different doses of apelin-13 was investigated on food intake in neonatal broilers at the age of five and seven days. The chicks had access to food immediately after injection and cumulative food intake was measured at half, 1, 2, 3, 4, 8 and 21 hr after injection. The 2-way ANOVA analyzed data showed that apelin-13 at dose of 1.00 μg significantly reduced food intake at 21 hr after injection in five-day old chicks. In addition, in dose of 1.50 μg, it could significantly reduce food intake at 2, 3, 4, 8 and 21 hr after injection. In seven-day-old chicks, the doses of 1.00 and 4.00 μg of apelin-13 had no effect on food intake compared to the control group. Apelin-13 at dose of 2.00 μg significantly reduced food intake at 8 and 21 hr after injection. The results of this study showed that apelin-13 had a reducing effect on food consumption in neonatal broiler chicks.

Abstract The objective of the present study was to evaluate the alterations in selected indicators of immune responses and oxidative stress of broilers fed with nano-manganese. One hundred-sixty 1-day-old broiler chicks were randomly assigned into four groups with three replicates. Birds were fed the same basal diet supplemented with nano-manganese oxide, as 0.00 (control group), 50.00, 100, or 150 mg kg^-1 of diet. The birds were vaccinated against avian influenza (AI), Newcastle disease (ND), infectious bronchitis (IB) and infectious bursal disease (IBD) as the standard vaccination schedule. Blood sample was taken from the brachial vein of birds on 42^th day. A significant decrease in antibody titer against sheep RBC was revealed in the nano-manganese 100 and 150 groups compared to the control group. In addition, the antibody titers against IB and ND were significantly lower in the all nano-manganese groups compared to the control group. No significant difference was observed for the antibody titer against AI and oxidative stress indices among the experimental groups. The findings in the present study suggested that nano-manganese at 50.00, 100 and 150 mg kg^-1 levels might suppress humoral immune response in broilers which should be taken into consideration in supplementation.

Abstract The objective was to investigate the multidrug resistance and presence of class 1 and 2 integrons in 300 Escherichia coli isolates obtained from 20 broiler farms during three rearing periods (one-day-old chicks, thirty-day-old chickens, and one day before slaughter) in Fars, South Iran. Results showed that 81.00%, 82.00%, and 85.00% of isolates were multidrug-resistant on the first day, thirty-day-old chickens, and one day before slaughter, respectively. Multidrug-resistant E. coli isolates were further examined for the presence of class 1 and 2 integrons using PCR assay. The existence of class 1 integron-integrase gene (intI1) was confirmed in 68.40%, 72.70%, and 60.90% of multidrug-resistant isolates from stage 1, stage 2, and stage 3 of the rearing period, respectively. The frequency of class 2 integron-integrase gene (intI2) during the first to the third stage of sampling was 2.60%, 25.50%, and 30.40%. Also, sequence analysis of the cassette arrays within class 1 integron revealed the presence of the genes associated with resistance for trimethoprim (dfrA), streptomycin (aadA), erythromycin (ereA), and orfF genes. The results revealed that percentages of antimicrobial resistance in E. coli isolates were significantly higher in the middle and end stages of the rearing period. In conclusion, widespread dissemination of class 1 integrons in all three stages and rising trends of class 2 integrons existence in E. coli isolates during the rearing period of broiler chickens could exacerbate the spread of resistance factors among bacteria in the poultry industry. Future research is needed to clarify its implication for human health.

Abstract Mycoplasma synoviae (MS) is a pathogen responsible for respiratory and locomotor disorders and causes major economic losses in poultry industry. Early and accurate diagnosis of MS infection plays a major role in control of the infection. This study was conducted to characterize Iranian field isolates of MS isolated from broiler chickens of West Azarbaijan province (Northwest of Iran), and differentiate them from vaccine strain MS-H. Two encoding genes, 16S rRNA and vlhA were employed. PCR results using primers related to 16s rRNA and vlhA genes were analyzed and compared. Out of 21 field samples, eight samples (38.0%) were positive using both sets of primers. Amplified products of vlhA gene were sequenced for MS strain identification. The results showed that Iranian field isolates of MS had high nucleotide and amino acid similarity. Iranian field isolates were distinct from vaccine strain MS-H. Results presented in this study showed that characterization of field isolates of MS by sequencing of vlhA gene and is beneficial for strain typing and differentiating them from vaccine strain. To our knowledge, this is the first study characterizing vlhA gene of MS isolates from broiler chickens in the West Azarbaijan province.