Project Number: 2050-21310-004-15-T
Project Type: Trust
Start Date: Dec 1, 2013
End Date: Jun 30, 2014
Aquaculture is the world’s most rapidly expanding agricultural activity due to many factors including static or declining wild fisheries, improved standard of living in some parts of the world and an increased awareness of the health benefits of eating fish. This expansion, however, is limited by the dependence of traditional feeds on fish meal as a primary protein source. Fish meal supplies have been overharvested worldwide and there are an increasing number of consumers who don’t want to buy farmed fish that have been fed marine harvested products. Recent research has demonstrated that fish meal and fish oil free diets, based upon soy protein concentrate and soy bean meal, when fed to rainbow trout can support growth equivalent to trout fed fish meal based diets under production conditions. This is considered a major breakthrough, but the cost of this diet is currently not economically viable in the long term. Alternative sources of protein and essential fatty acids need to be identified and blended into cost-effective sustainable trout feeds. RAS Corporation (abbreviated as RC hereafter) is to provide sustainably caught or farmed products to their customers. Through collaboration, USDA-ARS Small Grains and Potato Germplasm Research Unit (abbreviated as ARS hereafter) and RC will benefit from their complementary expertise and be able to leverage each other’s research efforts. This agreement supports the ARS’ mission of conducting research to improve nutrition, sustainability, and environmental compatibility of aquaculture and to reduce its dependence on marine fish protein. In addition, this collaborative research is directly aligned with RC business objective of providing environmentally responsible produced fish. The primary objective of this project is to develop alternative, sustainable, and environmentally responsible feeds for marine fish (Yellowtail, Seriola lalandi) that decrease dependence on ocean harvested products.
The collaborative research will focus on the inclusion of innovative feed ingredients in the diets that will be formulated and produced by ARS and fed to Yellowtail by RC. The collaborative research between ARS and RC will focus on the following three key tasks: 1) Determine the effect of alternative ingredients on the extrusion process and resulting pellet quality. All diets will be manufactured by cooking extrusion. Extrusion condition including barrel temperatures, pressure at the diet head, dry material feed rate, water addition rate, and specific mechanical energy will be monitored continuously and recorded. A sample of uncoated pellets will be taken to determine Pellet Durability Index with a Holmen tester.2) Determine the digestibility and palatability of the new ingredients for Yellowtail. Both palatability and apparent digestibility of nutrients and energy and amino acid availability will be determined from one group of fish with 20 fish per tank and three tanks of fish per diet and fed compounded extruded diets. All fish will be fed by hand to satiation so that feed consumption can be precisely measured to determine if the feed ingredient affects feed intake. The methodologies employed will include standard procedures that are well established in the investigators’ laboratories. Nutrient and energy availability will be determined by comparing the amount in feces relative to the amount in the feed. Standard methods will be used to estimate apparent digestibility coefficients (ADCs) as described below. Yttrium oxide will serve as the inert marker. A complete reference diet meeting or exceeding all known nutritional requirements for rainbow trout will be blended with the test ingredients in a 70:30 ratio (dry-weight basis) to form test diets. The reference diet will be fish meal free in order to have low enough levels of phosphorus to detect availability of phosphorus in the test ingredients. This diet has been used successfully in several digestibility and growth trials with rainbow trout. 3) Determine the effect of alternative ingredients on growth and feed efficiency or Yellowtail. Once digestibility of nutrients has been determined, the test ingredient will be evaluated in a growth trial with juvenile yellowtail following standard procedures. All diets will be manufactured as described in objective 1. Diets will be formulated to meet or exceed all known nutrient requirements and contain graded levels of the test ingredient with the maximum level being determined by the specific nutrient composition of the ingredients. A commercial fish meal based diet will be fed as a reference along with a diet of known composition without the test ingredient as a control. Experimental diets with juvenile fish will be fed for 9 weeks, with the average starting weight of the yellowtail between 20 and 40 grams/fish and will be fed by hand to satiation. Gain, feed intake, feed conversion ratio, protein and energy retention and survival will be determined. A 10 fish sample will be collected at the beginning of the trials and 5 fish from each tank will sampled at the end of the trial for body compositional analysis.