Adriane Grazziotin’s research while affiliated with Federal University of Rio Grande do Sul and other places

A proteína da pena é uma boa fonte proteica para dietas de animais, sendo um material de grande disponibilidade como subproduto da produção avícola. Neste trabalho, um hidrolisado protéico de penas produzido pelo microrganismo queratinolítico Vibrio sp. kr2 foi avaliado como suplemento em rações. Ratos da linhagem Wistar foram alimentados com sete dietas experimentais (n = 6 ratos por dieta) contendo diferentes fontes de proteína: caseina (CAS), proteína de soja, hidrolisado de pena, farinha de pena, e proteína de soja suplementada com 10 ou 20% (w/w) hidrolisado de pena, ou 20% hidrolisado de pena suplementado com metionina. Os valores de ganho de peso, consumo, digestibilidade verdadeira, coeficiente de eficiência alimentar, coeficiente de eficiência proteica (PER) e eficiência líquida proteica (NPR) foram similares para as dietas contendo proteína de soja e proteína de soja suplementada com 20% hidrolisado de pena e metionina. Valores inferiores para todos parâmetros nutricionais foram observados para as dietas contendo 10 ou 20% hidrolisado de pena, hidrolisado de pena e fariha de pena. A fonte protéica influenciou no peso final do fígado, rins e coração, porém as diferenças não foram significativas para cérebros. Estes resultados indicam que o hidrolisado de penas pode ser usado como fonte de proteína suplementar na formulação de rações desde que suplementados com metionina

Feather protein has been considered as a protein complement for animal diets, since it is largely available as a by-product of poultry processing. In this work, a feather protein hydrolysate produced by the keratinolytic microorganism Vibrio sp. kr2 was evaluated as a feed additive. Wistar rats were fed seven experimental diets (n = 6 rats per diet) containing different protein sources: casein (CAS), soybean protein, feather hydrolysate, feather meal, and soybean protein supplemented with 10 or 20% (w/w) feather hydrolysate, and 20% feather hydrolysate supplemented methionine. Values for weight gain, feed ingest, true digestibility, feed:gain ratio, Protein Efficiency Ratio and Net Protein Ratio were similar for diets containing soybean protein and 20% feather hydrolysate supplemented methionine. Lowest values for all nutritional parameters were observed for diets containing soybean protein supplemented with 10 or 20% (w/w) feather hydrolysate, feather hydrolysate and feather meal. Protein source had a considerable influence in the final weight of liver, kidney and hearth, although no significant differences were observed for brains. These results indicate that feather hydrolysate may be useful as supplementary protein in feed formulations.

A feather protein hydrolysate was produced using the keratinolytic bacterium Vibrio sp. strain kr2. Complete feather degradation was observed in medium containing up to 60 g L(-1) raw feathers. Cultivation on 40, 60 or 80 g L(-1) feathers for five days resulted in similar amounts of soluble protein, reaching maximum values around 2.5 g L(-1). Maximum yields of soluble protein were achieved at 30 degrees C and initial pH ranging from 6.0 to 8.0. Strain kr2 was effective in producing keratin hydrolysate from chicken feathers. Bacterial feather hydrolysate has the potential for utilization as an ingredient in animal feed or as organic fertilizer, thereby reducing the environmental impact of feather waste from the poultry industry.

Chicken feather hydrolysate was produced by proteolysis with a keratinolytic bacterium. Feather hydrolysate was produced by using the whole culture on 60gfeathers/l (WCH), or alternatively, using only the culture supernatant of cultivation on 10gfeathers/l (CSH). The amino acid composition of the resulting hydrolysates was determined, indicating deficiency in methionine, lysine and histidine. CSH showed higher amounts of sulfur-containing amino acids than WCH. In vitro digestibility with pepsin plus pancreatin was evaluated. WCH had lower digestibility than soy protein, but higher than feather meal and milled raw feathers. CSH had similar digestibility than casein and soy protein. Predicted nutritional parameters for WCH, CSH and feather meal were calculated. WCH showed higher predicted values of protein efficiency ratio (PER) and biological value (BV) than CSH, which presented higher protein digestibility-corrected amino acid scoring (PDCAAS). These bacterial feather hydrolysates showed potential for utilization as ingredients in animal feed.