Efecto de la combinación de alimento artificial y biomasa de artemia sp en cría intensiva de postlarvas de litopenaeus vannamei.

Abstract

The most cultivated shrimp species worldwide is Litopenaeus vannamei, this is due to its great adaptability to different environments. The increase in viral and bacterial diseases in shrimp farming has led to the use of a culture system with greater biosecurity and sustainability, which is why it has been chosen to reduce the exchange of water, achieving production in systems with zero or very low exchange. replacement. Raceways are intensive production systems used as nurseries in shrimp farming, where the main aim is to ensure the survival and health of the postlarvae; for which factors such as artificial and natural feeding, environmental factors and water quality intervene. One of the drawbacks of these intensive systems is the excessive nitrogen that enters the system, due to the fact that artificial foods are not totally consumed; food residues accompanied by shrimp excreta are converted into ammonia by microbial processes; This metabolite is toxic under conditions of pH and high temperatures, becoming a limitation for the intensive production of postlarvae. In this context, in the facilities of the Technical University of Machala in the Academic Unit of Agricultural Sciences, in the Mariculture Station located at coordinates 3 ° 17'31.2 "S 79 ° 54'50.3" W, belonging to the City of Machala, in the Province of El Oro, an experimental trial was carried out with the objective of evaluating the effect of the combination of artificial feed and Artemia sp biomass in the intensive rearing of Litopenaeus vannamei postlarvae, using weight gain as variables, the survival and the feed conversion factor in a time of 15 days. The population studied was 900 postlarvae, in PL-14 stage, with an average weight of 3.8 mg, distributed in 9 drawers with a volume of 30 L of seawater with a salinity of 28 UPS. The sowing density with which we worked was 10 PL L-1. The treatments consisted of 25 and 50% replacement of artificial feed with brine shrimp biomass and a control that consisted of 100% artificial feed. The artificial food used for feeding was a Microencapsulated food of 300 microns and 45% protein; The brine shrimp biomass used as replacement for the artificial feed was obtained from a culture of brine shrimp fed with microalgae of the Thalassiosira sp and Tetraselmis spp. species. The feeding was based on feeding tables for raceway and in the daily siphons, 8 feeding doses were added with a frequency of 3 hours. The average weight gain at the end of the experiment was for treatment 1 and 2 of 27.8 ± 4.8 mg and 27.2 ± 6.0 mg respectively where they did not present significant differences and for the control it was 40.36 ± 3.9 mg, it presented a significant difference in the ANOVA and the Tukey's test with a p value <0.05, this with respect to treatment 1 and 2. The average survival at the end of the experiment was for treatment 1 and 2 68.5 ± 4.95% and 50.66 ± 6.6% respectively and the control 32.0 ± 6.12 %, finding a statistically significant difference in treatment 1 with respect to treatment 2 and the control with a p value <0.05. The feed conversion factors were 1.55 (T1), 2.1 (T2) and 2.25 (Control). No significant differences were found, however, treatment 1 and 2 obtained lower values ​​compared to the control. The average dissolved oxygen concentration in the morning hours was 6.0 ± 0.3 ppm and an average of 5.5 ± 0.3 in the afternoon hours, the temperature presented an average value of 24.7 ± 0.8 ° C in the morning hours and 28.0 ± 0.2 ° C in the afternoon. It was concluded that there is a positive influence on the combination of artificial feed with brine shrimp biomass regarding the survival of Litopenaeus vannamei postlarvae.