No abstract

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 (3.2 and 6.4 µg 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.

Mycoplasma synoviae infection of hens has been associated with problems of eggshell quality called eggshell apex abnormalities (EAA). Little is known about the quality of EAA eggs from a commercial point of view, especially during their storage. The study aimed to examine the differences between EAA and normal eggs during storage under controlled conditions in 2 seasons, summer and winter, by comparing internal and external quality parameters. In a conventional egg production farm with white laying hens of varying ages in the city of Bastos, state of São Paulo, Brazil, 232 eggs were used in the summer season and 400 eggs in the winter season. Half of the eggs had EAA, and the other half were considered normal eggs for each season. The eggs were analyzed at 2, 7, 14, 21, and 28 d after being laid and stored from 24.6 to 25.8°C in summer and from 24 to 25°C in winter. There was no difference (P > 0.05) in the average egg weight between EAA and normal eggs at any studied time point, but in both seasons, the weight loss in EAA eggs was higher than in normal eggs. The losses in Haugh unit scores from the first to the last measurements were approximately 40% regardless of egg type or season of production. In comparing eggshell thickness, only the apices of the EAA eggs were thinner (P < 0.0001) than normal eggs in the summer, but in the winter, the EAA egg apices (P < 0.0001) and sides (P = 0.03) were both thinner. The presence of EAA did not affect the eggshell weight (P > 0.05) or eggshell percentage (P > 0.05). The eggshell strength of the EAA eggs was lower (P < 0.0001) than normal eggs in both the summer (16.57%) and winter (19.86%). The presence of EAA did not affect the internal quality of the egg, but was related to a greater loss of external quality and weight during storage.

The mite Allopsoroptoides galli has recently been identified parasitizing commercial chickens, São Paulo State/Brasil, causing severe dermatitis on all parts of the animal's body and a significant decline in productivity, particularly in egg production. The aim of the present study in A. galli infestation was to investigate the impact on laying hens' performance and egg quality. A total of 100 56-week-old Hy-line white laying hens were used. The birds were divided into 2 groups, with 10 replicates of 5 birds in each group. The experimental groups consisted of a non-infested group (hens free of theA. galli) and an infested group (hens presenting A. galli). The infestation with A. galli did not significantly influence feed intake but caused a significant reduction in the body weight of the hens and caused a decrease in egg production, therefore promoting worse feed conversion. The egg weight was reduced; however, the infestation did not significantly affect the internal quality of the eggs, which was measured according to the yolk color, albumen height, and Haugh units, or the quality of the shell, based on its percentage, thickness, and strength. It can be concluded that anA. galli infestation promotes a reduction in body weight, egg production, and egg weight in laying hens, therefore worsening feed conversion.

Pesq. Vet. Bras. 34(8):760-762, agosto 2014 760 RESUMO.-[Informação adicional sobre um surto de sarna causado por Allopsoroptoides galli (Acari: Psoroptoididae) em uma granja de poedeiras no Estado de São Paulo.] Este artigo acrescenta informações adicionais sobre um surto de sarna causado por Allopsoroptoides galli em uma instalação comercial de galinhas de postura no estado de São Paulo, Brasil. Approximadamente metade das 76.000 aves, com várias idades, mantidas em uma granja, foram infestadas. Um total de 12 galinhas sem prévio contato com os ácaros e infestadas experimentalmente apresentaram sinais clínicos semelhantes aos diagnosticados em galinhas naturalmente infestadas, tais como dermatite escamosa generalizada, presença de material mucoso, crostas amareladas na pele e em torno dos câlamos, perda de penas e forte odor desagradável. A perda na produçãode ovos foi estimada em 30%. As possíveis fontes de infestação foram aves silvestres observadas no chão próximo aos galpões e telhados.