Feed management of Litopenaeus vannamei in a high density biofloc system

• Published in: Aquaculture 2021-11, Vol.544, p.737074, Article 737074
• Main Authors: Weldon, Alexis, Davis, D. Allen, Rhodes, M., Reis, J., Stites, W., Ito, P.
• Format: Article
• Language: English
• Subjects: Biofloc; Feed efficiency; Feed management; Natural foods; Whiteleg shrimp
• ISSN: 0044-8486; 1873-5622
• DOI: 10.1016/j.aquaculture.2021.737074

One area with significant potential for improvement in commercial shrimp production is feed management. Consequently, feed management is critical to optimize especially in intensive systems. Hence, the purpose of this study was to observe the response of Litopenaeus vannamei to different feed inputs in an intensive production system. The growth trial was conducted in an outdoor biofloc recirculating aquaculture system consisting of 24, 0.75m2 culture tanks stocked at a density of 160 shrimp/m2 (initial weight 0.17 g) and grown for 63 days. Treatments consisted of seven varying feeding rates (30%, 60%, 90%, 105%, 120%, 135%, and 150%) which was offered 4 times per day, and an eighth treatment that was fed 150% of the standard feeding rate using a belt feeder that fed six times daily. At the conclusion of the trial, significant differences in final weight and feed conversion ratio were observed. Regression analysis performed on the first three feeding rates (30%, 60% and 90%) determined that natural foods were responsible for approximately 280 g of total shrimp biomass, or 17% of maximum biomass gain. Results indicated that increasing feed rates over 100% of the standard rate led to an increase in final weight, albeit shrimp growth shows signs of approaching plateau, and FCR increases. Results demonstrate efficacy of culturing shrimp in high density biofloc systems across a range of feed inputs and achieving desirable growth (1.27–1.55 g/week), final weight (11.62–14.15), feed conversion ratios (1.04–1.19), and survival (94.17–96.94). Restrictive feeding produces the most efficient use of feed, albeit at a cost of total weight gain. As maximum gain is approached, there is an inflection point at 101% of the standard feeding rate where growth and feed utilization decline rapidly leading to increase in FCR and smaller gains in growth. Hence, a goal for maximum gain will be offset by increased FCR. Consequently, to maximize nutrient utilization it is recommended to feed below maximum gain. •Increasing feed inputs led to increased shrimp weight, with lower feed efficiency.•Shrimp can be grown at high densities in biofloc systems and achieve desirable growth.•Restrictive feeding results in the highest feed efficiency.•Natural foods present in the system provided approximately 280 g to shrimp biomass.