EVALUATION OF STORAGE CONDITIONS ON THE AMINO ACIDS, FATTY ACIDS, VITAMINS AND ELEMENTAL PROFILES OF AQUAFEED

Abstract

Aquafeed performance improvement provides an opportunity to enhance the sustainability of aquafarming practices, sourcing the expanse of this ‘fast-growing food sector’ catering to global nutrition requirements. Aquaculture productions are largely dependent on availability of quality aquafeeds that govern fish nutrition. World over, nearly half of the aquaculture production is feed-based. With growing food fish demand, feed based aquaculture will dictate future aquaculture growth and sustainability. Moreover, sustainable aquaculture growth will be dependent on finding alternative feed ingredients as suitable replacements to compensate fishmeal, fish oil scarcity and impelled increments in feed costs. Judicious storage of feed can suitably meet nutritional demands of fed-aquaculture. Largely, the nutrient profile of aquafeed determines fish welfare and consequent consumer health. Additionally, proper storage of feed have important role in the economic, health and welfare aspect of aquaculture production. Appropriate storage and timely utilization of feed can prevent induction of food linked hazards in the food chain. Storage conditions, especially duration and temperature are important factors affecting biochemical profile viz; fatty acid, protein, amino acid and vitamin composition as well as microbiological quality of feeds. Effects of duration and temperature variables on stored feed rations requires timely assessments as a measure for assurance of feed quality. Present work is designed to evaluate effect of different storage conditions on feed nutrient quality. The study aims at assessing incurred losses in nutritional quality of compounded feeds stored over long-term duration under variable condition of storage temperatures. This work also aims at determining the effects of feed composition and feed processing technique on the nutritional quality of feeds.The study is based on evaluation of impact of storage variables, temperature and duration, on the quality parameters of PARUL PURI 2K19/PHD/BT/07 vii formulated aquafeeds. Greater duckweed, Spirodela polyrhiza was used as alternative feed ingredient for partial substitution of fishmeal in extruded diet (diet1) and non-substituted pelleted diet (diet 2) is taken as control. Feeds were stored at four different temperature conditions comprising low temperatures (LT1= -20o C, LT2= 4o C); ambient (AT = 17o C - 31.5o C for diet1; 15.8 o C -31 o C for diet 2) and high temperature (HT= 45o C), for six months. Bimonthly assessment of nutritional profile for biochemical composition; ash, moisture, crude lipid, crude protein, carbohydrates as nitrogen free extract (NFE), is performed along with changes in storage profile of essential, non-essential, free amino acids; saturated, unsaturated, free fatty acids; fat and water-soluble vitamins; micro and macro-elements, gross energy (GE), assessing aflatoxin incidences, if any; at variable temperature conditions during storage. From the results it is noteworthy that storage temperature and duration have highly significant effects (P< 0.05) on changes in crude protein, crude lipid, moisture, NFE, and GE content of feeds. Incurred losses in vitamins A, E, K, B2, B12 and C are noteworthy across storage duration 60-day onwards, at all temperatures, for both diets. Elemental interaction and moisture notedly impact element profile changes. Aflatoxin incidences unreported in the assessments denote effects of dietary combats, good storage, and packaging conditions. Significant losses, from initial to six months are noteworthy for total saturated, monounsaturated and polyunsaturated fatty acids (n-3PUFA, n-6PUFA) for both diets at all storage temperatures. There is an overall decrease in total essential and total non essential amino acids along storage duration. Overall best restorative conditions for most nutrients is determined as, within two months of LT1 storage. The study helps understand timely utilization of stored feeds for maximizing their nutritional benefit to the fish. Through this work, assessed percentage loss of each nutrient in compounded diets may help specify need to develop feed formulae accounting incurred loss of nutrients during the storage period. Substantially, these findings may provide helpful information for fish farmers in managing feed storage of formulated feeds with an aim to PARUL PURI 2K19/PHD/BT/07 viii prolong their shelf-life; safeguarding significant amount of the total production costs of fed-aquaculture.