Poultry feather is the most abundant keratinous material in the nature because β-keratin represents around 90% of feather weight1. But; feather wastes are causing harm to environment, therefore; it is necessary to manage its accumulation by economically safe manner2, 3. These wastes can be utilized in the ruminant feeding but, it has been reported that feather protein is poorly digested in birds and mammals4. The poor digestion of keratin molecules is because of disulfide bonds which are hard to degrade by animal’s proteolytic enzymes5. Moreover, lack of feather protein in essential amino acids decreases its biological and nutritive value.
Improvement of feather digestibility and amino acid balance could be achieved by the biological treatments. The ability of different microorganisms for poultry feathers hydrolysis has been reported6,7. Fermented feather meal production by non-pathogenic microbes may provide diets of ruminants with high quality and cost effective source of protein. A study was carried to investigate effects of partial substitution of ration’s soybean meal by biologically treated feathers (BTF) on rumen fermentation characteristics (in vitro).
Keratinase production time course was performed by ten microbial isolates (3 fungal, 3 actinomyces and 4 bacterial isolates) under static and shaking conditions using turkey feather- synthetic medium. The chemical composition and amino acid analysis for the crude feathers, BTF and soybean meal were determined according to AOAC methods. Two in vitro experiments were conducted to study the effects of crude feathers, BTF and modified ruminant rations (in which soybean meal were substituted by the BTF in 10, 20 and 30%) on rumen fermentation characteristics. Ration’s Dry Matter (DM), Organic Matter (OM), Neutral detergent fibre (NDF) and Acid detergent Fibre (ADF) degradability by rumen microorganisms were tested using batch culture technique. Ruminal final pH, ammonia-nitrogen, total volatile fatty acids and short chain fatty acids concentrations were determined after 24 h of incubation. The total gas production volume was determined using 100 mL glass syringes.
It was observed that Bacillus licheniformis ALW1 was the most potent keratinase producer strain under static condition at 37°C for four days of incubation. Feather biological treatment by Bacillus licheniformis increased its content of essential sulphur amino acids. The degradability of BTF by rumen microorganisms was 4 times higher than crude feather degradability. There were no significant differences between control and partially substituted (R10 and R20) rations in all of rumen fermentation characteristics. The utilization of BTF as substitute for costly soybean meal in ruminant’s rations up to 20% had no negative effect on all rumen fermentation characteristics.
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25 August, 2019