Research Article: Properties and shelf-stability of co-dried common kilka (Clupeonella cultriventris) protein hydrolysate with agricultural residues as a new protein feed supplement

Developing aqua/ animal feeds from underutilized fish and agricultural by-products using hydrolyzed technology is an excellent way to provide proteins for aquaculture/ animal farming. This study reports development of a new protein feed supplement, based on fish protein hydrolysate and agricultural residues, on a pilot scale and investigates physicochemical properties, microbial quality, and shelf-stability of the product. The production conditions were based on lab-scale experiences. Accordingly, fish protein hydrolyzed solution containing 16.58% crude protein, 63.35% moisture, and 15.52% fat was mixed with agricultural by-products, i.e. sesame meal, rice bran, and soybean meal as fillers (60:40 w/w) and dried at 40°C for 6 h. The dried mixture was grounded after cooling, then packed in sealed plastic bags, and stored for 180 days at ambient temperature. The protein feed supplement contained 58.23% crude protein, 16.18% fat, 8.85% moisture, 9.10% ash, 2.6% fiber, 1.489% calcium, 0.89% phosphorous, and 5.34% carbohydrates of dry weight. Total essential and non-essential amino acids were 19.41g/ 100g and 20.36 g/ 100g of dry weight respectively. The protein feed supplement contained significant essential fatty acids. Levels of pH and TVB-N of the protein feed supplement increased to 5.30 and 65.20 mg/100g at the end of the study. After 180 days, there were no yeast and mold in the samples and it was still pathogen-free.