The Pacific white shrimp is a tropical and ectothermic species, thermoregulating inefficiently and at a high energy cost. The ideal temperature for its cultivation ranges from 27-30 ºC and autumn and winter temperatures or subtropical regions can affect its performance. Thus, the use of biotechnological additives that include long-chain fatty acids in shrimp nutrition can be an alternative, aiming at greater permeability of the cell membrane and better performance of the animals.
Aurantiochytrium sp. is defined as a marine protist, heterotrophic and has occurrence ranges from the tropical waters to the temperate. It can produce bioactive compounds and accumulate large amounts of polyunsaturated fatty acid DHA (docosahexaenoic acid). The inclusion of Aurantiochytrium flour in the diet may be the key to better maintenance of shrimps in low temperatures by increasing their immune system and the use of nutrients. Test ingredient was analyzed by CSIRO staff using established best practice methods at the Queensland Bioscience Precinct Analytical Laboratory for chemical composition and fatty acids and the results are shown in Table 1. The analyzes were based on the Association of Official Agricultural Chemists (AOAC, 2016). Five treatments with three replications each were carried out with the inclusion of Aurantiochytrium flour doses (0, 1, 2, 3 and 4%) in practical diets for P. vannamei, cultivated in clear water at a temperature of 22 ºC. The experiment lasted 63 days and the experimental units had 400 L of useful volume. The stocking density was 100 shrimp per m3. The initial weight of the animals was 3.8±0.02 g. The water quality parameters were maintained within the rates defined for the experiment, Temperature: 22.1±0.2 ºC, Dissolved Oxygen 7.0±0.1 mg/L, Ammonia 1.1±0.4 mg/L and Nitrite 0.2±0.2 mg/L. The results of zootechnical performance are shown in Table 2. The average survival was 98.0±2.0%. The results showed no statistical differences. The experiment resulted in excellent survival, considerable weight gain and satisfactory productivity when considering that the entire cultivation took place at a suboptimal temperature. Therefore, the use of Aurantiochytrium flour was equivalent to the control diet, without harming the performance of the shrimp and with satisfactory results for the temperature used. Different inclusion doses can be tested.