Quantitative evaluation of amino acids and fatty acids profiles of biosilage produced from chicken waste

One way to turn chicken waste into high value-added product is to produce fermented silage (biosilage). This product is superior to fish powder due to its characteristics such as high quality protein, probiotic bacteria and low price and can be considered as a suitable alternative for feed industry. Silage can be produced from protein wastes by both acidic and biological methods. The acidic method of producing silage (acidic silage) uses a variety of organic and inorganic acids such as formic acid and sulfuric acid. In the production of biological silage, two methods of autolysis (using internal enzymes) and fermentation (using microbial starters) are used. Starters used for inoculation are mainly from the group of lactic acid bacteria. To produce silage, protein wastes are used, especially fish wastes. Since poultry waste has not been used for biosilage production in the country so far, the aim of the present study is to produce biological silage from chicken waste and evaluate the profile of amino acids and fatty acids in the biosilage. 

Chicken intestine was prepared from meat production complex in Golestan province, Kordkoy city and also Simin Naz poultry industrial slaughterhouse in Sari and was transferred to the processing pilot of Caspian Sea Ecology Research Institute in the shortest time in cold container. During the biosilage production process, protein-degrading bacteria (containing protease enzymes such as gram-positive sporulated bacteria) and acid-producing bacteria (to reduce the pH of the suspension and accelerate the fermentation process, such as lactic acid bacteria) were used as initiator bacteria or microbial starters for intestinal digestion. The product was analyzed for protein, fat, moisture and ash according to standard methods. In this study, high performance liquid chromatography (HPLC) of Cecil model (Seri 200) was used for amino acids analysis. Samples were prepared for assaying amino acids profile in two stages including hydrolysis and derivatization and the results were expressed in grams per 100 grams of substrate. To determine the fatty acids composition of the biosilage sample, the fat was first extracted. In order to evaluate the profile of fatty acids, a Shimadzu model gas chromatography device was used and the results were expressed as a percentage. 

The product produced contained about 60% protein and 21% fat. According to the results, the total of essential amino acids in the produced biosilage was 24.416, the total of non-essential amino acids was 30.959 and the total of essential and non-essential amino acids was 55.375 g per 100 g of substrate. Among essentialamino acids, the highest amount belonged to the amino acids leucine (7.334±0.45 g/100g) and valine (4.71±0.27 g/100g) and among non-essential amino acids, the highest amount belonged to glutamic acid (10.6±0.73 g/100g) and alanine (5.864±0.81 g/100g). It was also found that all essential amino acids except tryptophan are present in biosilage. Evaluation of biosilage fatty acids profile revealed that the total amount of saturated fatty acids (SFA) was 33.57%, monounsaturated fatty acids (MUFA) was 41.17% and polyunsaturated fatty acids (PUFA) was 24.36%. It was further found that in biosilage the total omega 3 was 2.07%, the total omega 6 was 22.91% and the sum of EPA and DHA was 2.06%.The profile of amino acids and fatty acids in the biosilage produced from chicken waste is almost the same as that of other products made from protein waste (such as fish meal, fish waste biosilage and hydrolyzed protein powder). This property, along with cheap production and high nutritional value, allows the use of biosilage obtained from chicken waste in the livestock, poultry and aquatics feed industry.