Utilization of crystalline amino acids by Pacific white shrimp (Litopenaeus vannamei)

ABSTRACT

In view of the variability in recommendations for essential amino acid (EAA) and the use of amino acids supplements in shrimp diets, this study was designed to evaluate the efficacy of crystalline amino acids (CAA) in practical shrimp feeds. The basal diet was designed to contain 30% protein and 6% lipid. The primary protein source of the basal diet included: 5% fishmeal, 37% soybean, and 5% gelatin. The intact protein was incrementally reduced to produce diets with 28%, 26%, 24%, and 22% protein. In a second series of diets, CAA were supplemented to the reduced protein diets to return the diets to 30% crude protein. Thus, producing a series of diets containing 30% protein with 2%, 4%, 6%, and 8% crystalline amino acids. The trial was conducted twice to confirm results. Data within treatments for both trials were variable, resulting in limited statistical differences. From a biological standpoint, percentage weight gain (PWG) and mean final weight (MFW) appeared to decrease with intact protein level of the diet (R² value [PWG], trial 1: 0.30, trial 2: 0.34, R² value, [MFW] trial 1: 0.44, trial 2: 0.38). None of the diets with supplemented CAA appeared to have reached the same MFW or PWG as the basal diet. Another trial was run using a fishmeal-based diet (30% CP), which in theory should be replete in all essential amino acids, and a soybean meal-based diet at two different protein levels (30% and 35% CP). The soybean meal-based diets were supplemented with essential CAA in one set and only methionine in another to reach the same level as a percent protein, compared to the fishmeal-based diet. No significant differences were observed between the diets in terms of PWG. However, the fishmeal-based diet seemed to outperform most of the other diets in terms of protein retention efficiency. Based on the results of these trials, it is questionable whether CAA are sufficiently utilized by shrimp.

KEYWORDS:

• Crystalline amino acids
• Litopenaeus vannamei
• soybean meal
• growth

Acknowledgments

Authors would like to express their gratitude to all who took the time to critically review this manuscript. We would also like to thank those who helped with this research at the Claude Peteet Mariculture Center and E.W. Shell Research Station, School of Fisheries, Aquaculture and Aquatic Sciences, Auburn University. Also, thanks to the students who help maintain daily management. Mention of trademark or proprietary product does not constitute an endorsement of the product by Auburn University and does not imply its approval to the exclusion of other products that may also be suitable.

Disclosure statement

No potential conflict of interest was reported by the author(s).

Additional information

Funding

This work was supported in part by the Alabama Agricultural Experiment Station and the Hatch program (ALA016-08027) of the National Institute of Food and Agriculture, U.S. Department of Agriculture, as well as the Soy Aquaculture Alliance.