RESUMO
Feathers make up 7% of the total weight of adult chickens and keratin protein makes up 85% of the feathers. Today, the keratinase enzymes of some Bacillus strains are used to degrade and process raw keratin waste for animal and poultry feed. According to various studies, the probiotic properties of some spore-shaped Bacillus have also been proven. The study aimed to isolation of the keratinolytic Bacillus bacteria that they have probiotic properties for using in the livestock and poultry feed industry. We were able to isolate 8 strains of Bacillus licheniformis with kreatin degrading properties from the soil of Baharan chicken slaughterhouse (Qom city, Iran) applying heat shock, alcohol- and keratin-rich culture medium, and after microscopic and biochemical analysis, 16S rDNA gene was isolated. The measurement results of keratinase activity showed that the three strains of Bacillus licheniformis pvkr6, pvkr 15, and pvkr41 had the highest activity with 124.08, 101.1, and 100.18 U/ml. The results of probiotic properties evaluation also revealed that among all the isolates, only Bacillus licheniformis pvkr15 and Bacillus licheniformis PTCC 1595 (positive control) were γ-hemolytic strains. The percentage of surface hydrophobicity of the strains was obtained from 3.27 to 30.57. It was also shown that, on average, all the strains had acceptable susceptibility to the tested antibiotics except penicillin G. Bacillus licheniformis pvkr15 with highest keratinase activity (101.1U/ml) was considered an optional probiotics due to its abilities such as (biofilm formation, being safe cause of γ-hemolytic activity, high susceptibility to antibiotics such as streptomycin, gentamicin, cefixime, amoxicillin, tetracycline, vancomycin, erythromycin and having a moderate hydrophilic (hydrophobicity: 19.09%), high survivability in pH 2, 2.5 and 3, strong resistance to bile salts and moderate antagonistic activity against pathogenic bacterium like Proteus mirabilis and the ability to grow under anaerobic conditions). By using this strain, after hydrolysis of keratin protein in the feather structure, to replace part of the protein of livestock and poultry feed, not only is no need to separate bacteria from the feed, but also the strain play role of an useful and effective additive in animal growth.
As penas representam 7% do peso total das galinhas adultas e a proteína de queratina compõe 85% das penas. Hoje, as enzimas queratinase de algumas cepas de Bacillus são usadas para degradar e processar resíduos de queratina brutos para alimentação de animais e aves. De acordo com vários estudos, as propriedades probióticas de alguns Bacillus em forma de esporos também foram comprovadas. O estudo teve como objetivo o isolamento das bactérias queratinolíticas Bacillus que possuem propriedades probióticas para uso na indústria de ração animal e avícola. Conseguimos isolar 8 cepas de Bacillus licheniformis com propriedades degradantes de creatina do solo do abatedouro de frangos de Baharan (cidade de Qom, Irã) aplicando choque térmico, meio de cultura rico em álcool e queratina e, após análise microscópica e bioquímica, o gene 16S rDNA foi isolado. Os resultados da medição da atividade da queratinase mostraram que as três cepas de Bacillus licheniformis pvkr6, pvkr15 e pvkr41 tiveram a maior atividade com 124,08, 101,1 e 100,18 U/ml. Os resultados da avaliação das propriedades probióticas também revelaram que dentre todos os isolados apenas Bacillus licheniformis pvkr15 e Bacillus licheniformis PTCC 1595 (controle positivo) eram cepas γ-hemolíticas. A porcentagem de hidrofobicidade superficial das cepas foi obtida de 3,27 a 30,57. Também foi demonstrado que, em média, todas as cepas apresentaram suscetibilidade aceitável aos antibióticos testados, exceto penicilina G. Bacillus licheniformis pvkr15 com maior atividade de queratinase (101,1U/ml) foi considerado um probiótico opcional devido às suas habilidades como formação de biofilme, sendo causa segura de atividade γ-hemolítica, alta suscetibilidade a antibióticos como estreptomicina, gentamicina, cefixima, amoxicilina, tetraciclina, vancomicina, eritromicina e ter uma hidrofílica moderada (hidrofobicidade: 19,09%), alta capacidade de sobrevivência em pH 2, 2,5 e 3, forte resistência aos sais biliares e atividade antagonista moderada contra bactérias patogênicas como Proteus mirabilis e a capacidade de crescer em condições anaeróbicas. Ao utilizar esta cepa, após a hidrólise da proteína queratina na estrutura da pena, para substituir parte da proteína da ração de gado e aves, não só não há necessidade de separar as bactérias da ração, mas também a cepa desempenha um papel útil e eficaz aditivo no crescimento animal.
Assuntos
Animais , Solo , Resíduos , Probióticos , Bacillus licheniformis , Queratinas , Ração AnimalRESUMO
Feathers make up 7% of the total weight of adult chickens and keratin protein makes up 85% of the feathers. Today, the keratinase enzymes of some Bacillus strains are used to degrade and process raw keratin waste for animal and poultry feed. According to various studies, the probiotic properties of some spore-shaped Bacillus have also been proven. The study aimed to isolation of the keratinolytic Bacillus bacteria that they have probiotic properties for using in the livestock and poultry feed industry. We were able to isolate 8 strains of Bacillus licheniformis with kreatin degrading properties from the soil of Baharan chicken slaughterhouse (Qom city, Iran) applying heat shock, alcohol- and keratin-rich culture medium, and after microscopic and biochemical analysis, 16S rDNA gene was isolated. The measurement results of keratinase activity showed that the three strains of Bacillus licheniformis pvkr6, pvkr 15, and pvkr41 had the highest activity with 124.08, 101.1, and 100.18 U/ml. The results of probiotic properties evaluation also revealed that among all the isolates, only Bacillus licheniformis pvkr15 and Bacillus licheniformis PTCC 1595 (positive control) were γ-hemolytic strains. The percentage of surface hydrophobicity of the strains was obtained from 3.27 to 30.57. It was also shown that, on average, all the strains had acceptable susceptibility to the tested antibiotics except penicillin G. Bacillus licheniformis pvkr15 with highest keratinase activity (101.1U/ml) was considered an optional probiotics due to its abilities such as (biofilm formation, being safe cause of γ-hemolytic activity, high susceptibility to antibiotics such as streptomycin, gentamicin, cefixime, amoxicillin, tetracycline, vancomycin, erythromycin and having a moderate hydrophilic (hydrophobicity: 19.09%), high survivability in pH 2, 2.5 and 3, strong resistance to bile salts and moderate antagonistic activity against pathogenic bacterium like Proteus mirabilis and the ability to grow under anaerobic conditions). By using this strain, after hydrolysis of keratin protein in the feather structure, to replace part of the protein of livestock and poultry feed, not only is no need to separate bacteria from the feed, but also the strain play role of an useful and effective additive in animal growth.