ABSTRACT
Mite infestations in laying hens can cause losses to producers due to stress, reduced egg production and even death of birds. A new species of mite, Allopsoroptoides galli (A. galli), Analgoidea: Psoroptoididae, was recently identified in commercial laying farms in Brazil, causing damage due to its highly aggressive infestation that results in a sharp drop in egg production and culling. The present study evaluated the acaricidal action of a formulation containing fluralaner (Exzolt) against A. galli. Thirty-four laying hens naturally infested with A. galli were equally divided into a fluralaner-treated group and an untreated control group. The fluralaner-treated group received Exzolt in drinking water at a dose of 0.05 mL/kg body weight (equivalent to 0.5 mg fluralaner/kg body weight), twice, 7 d apart. Both groups were followed for 70 d evaluating the level of infestation by counting mites in skin scrapings and assessment of skin lesions. The average mite count of the treated group decreased significantly, dropping from 61.6 to 3.8 mites (D+7 to D+70). The efficacy progressively increased on subsequent days, reaching 98.8% on d +56 post-treatment and 96.9% on d +70. Recovery of skin lesions was observed after administration of Exzolt, showing a marked remission in the degree of lesions (2.5 on d -14 to 0.2 on d +70). The mean number of mites in the untreated control group ranged from 79.3 to 124.1 and the lesion score from 2.6 to 2.9, thus remaining stable throughout the study. The results obtained in the present study demonstrated that Exzolt administered at a dose of 0.05 mL of product/kg body weight (equivalent to 0.5 mg of fluralaner/kg body weight), twice at a 7-d interval, in drinking water was effective in the treatment of the mite Allopsoroptoides galli in naturally infested laying hens.
Subject(s)
Drinking Water , Mite Infestations , Mites , Poultry Diseases , Animals , Body Weight , Chickens , Female , Isoxazoles , Mite Infestations/drug therapy , Mite Infestations/veterinary , Poultry Diseases/drug therapyABSTRACT
The constant use of synthetic antibiotics as growth promoters can cause bacterial resistance in chicks. Consequently, the use of these drugs has been restricted in different countries. In recent years, antimicrobial peptides have gained relevance due to their minimal capacity for bacterial resistance and does not generate toxic residues that harm the environment and human health. In this study, a Ctx(Ile21)-Ha antimicrobial peptide was employed, due to its previously reported great antimicrobial potential, to evaluate its application effects in laying chicks challenged with Salmonella Enteritidis, resistant to nalidixic acid and spectinomycin. For this, Ctx(Ile21)-Ha was synthesized, microencapsulated and coated with hypromellose phthalate (HPMCP) to be released in the intestine. Two different doses (20 and 40 mg of Ctx(Ile21)-Ha per kg of isoproteic and isoenergetic poultry feed) were included in the chick's food and administered for 28 days. Antimicrobial activity, effect and response as treatment were evaluated. Statistical results were analyzed in detail and indicate that the formulated Ctx(Ile21)-Ha peptide had a positive and significant effect in relation to the reduction of chick mortality in the first days of life. However, there was moderate evidence (p = 0.07), not considered statistically significant, in the differences in laying chick weight between the control and microencapsulation treatment groups as a function of time. Therefore, the microencapsulated Ctx(Ile21)-Ha antimicrobial peptide can be an interesting and promising option in the substitution of conventional antibiotics.
ABSTRACT
Microencapsulation is a potential biotechnological tool, which can overcome antimicrobial peptides (AMP) instabilities and reduce toxic side effects. Thus, this study evaluates the antibacterial activities of the Ctx(Ile21)-Ha AMP against multidrug-resistant (MDR) and non-resistant bacteria and develop and characterize peptide-loaded microparticles coated with the enteric polymers hydroxypropylmethylcellulose acetate succinate (HPMCAS) and hydroxypropylmethylcellulose phthalate (HPMCP). Ctx(Ile21)-Ha was obtained by solid phase peptide synthesis (SPPS) method, purified and characterized by HPLC and Mass Spectrometry. The peptide exhibited potent antibiotic activities against Salmonella enteritidis, Salmonella typhimurium, Pseudomonas aeruginosa (MDR), Acinetobacter baumannii (MDR), and Staphylococcus aureus (MDR). Ctx(Ile21)-Ha microencapsulation was performed by ionic gelation with high efficiency, maintaining the physical-chemical stability. Ctx(Ile21)-Ha coated-microparticles were characterized by DSC, TGA, FTIR-Raman, XRD and SEM. Hemolytic activity assay demonstrated that hemolysis was decreased up to 95% compared to single molecule. In addition, in vitro release control profile simulating different portions of gastrointestinal tract was performed and showed the microcapsules' ability to protect the peptide and release it in the intestine, aiming pathogen's location, mainly by Salmonella sp. Therefore, use of microencapsulated Ctx(Ile21)-Ha can be allowed as an antimicrobial controller in monogastric animal production as an oral feed additive (antimicrobial controller), being a valuable option for molecules with low therapeutic indexes or high hemolytic rates.
