Title: Development of a semipurified test diet for determining amino acid requirements of Florida pompano Trachinotus carolinus reared under low-salinity conditions Author
Submitted to: Aquaculture
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: October 28, 2013
Publication Date: November 4, 2013
Citation: Riche, M.A. 2013. Development of a semipurified test diet for determining amino acid requirements of Florida pompano Trachinotus carolinus reared under low-salinity conditions. Aquaculture. 420-421:49-56. Interpretive Summary: A principal roadblock to the commercial production of Florida pompano in low-salinity is the lack of efficient and affordable feeds. Identifying the requirements and the proper balance of key nutrients such as essential amino acids will allow the development of feeds that are less expensive and more efficient. In order to establish these requirements, suitable test diets need to be developed that are well accepted by Florida pompano and result in adequate growth. The identification of appropriate dietary proteins, the right balance of essential amino acids, and the ability to absorb and use purified amino acids for growth are needed to develop a suitable test diet. Using approaches established for other fish and terrestrial animals, eight different test diets were prepared. These diets contained one of two different protein sources (casein and corn gluten meal) and four different dietary amino acid patterns prepared by adding, or not adding purified amino acids. These amino acid patterns mirrored those found in pompano eggs, whole pompano, menhaden fish meal, and a diet without additional purified amino acids to determine how efficiently Florida pompano can use purified amino acids. Casein was a better ingredient than corn gluten meal and a casein-based diet with the amino acid pattern mirroring whole Florida pompano makes a suitable test diet to determine their amino acid requirements. Although pompano utilize purified amino acids for growth, additional processing steps may make the purified amino acids more efficiently utilized. Development of this test diet will allow for establishing the amino acid requirements for Florida pompano resulting in less expensive and more efficient diets.
Technical Abstract: Two trials were conducted to develop a semipurified test diet for determining indispensable amino acid (IAA) requirements for Florida pompano Trachinotus carolinus. The objective of the first trial was to evaluate casein and corn gluten meal as principal intact protein sources, and the ability of Florida pompano to utilize L-crystalline amino acids in the diet. Eight isonitrogenous (42% crude protein) and isoenergetic (22.0 kJ/kg) diets were formulated. A 2x4 factorial was employed to evaluate the two intact proteins, each with four amino acid profiles that mimicked the ratio of IAA in pompano whole body, pompano unfertilized eggs, menhaden fish meal, or unsupplemented negative control. Growth and efficiency were significantly better (P<0.05) for each of the IAA profiles with the casein-based diets. The objective of the second trial was to re-evaluate the same IAA profiles in 46% crude protein and 22.0 kJ/kg casein-based diets to evaluate their performance relative to each other and to a practical type fish meal-based control diet. Growth and feed conversion were significantly better (P<0.05) in pompano fed the diet supplemented to mimic the ratio of the pompano whole body IAA profile. Growth and feed efficiency in pompano fed the diet containing the whole body IAA profile were 94% and 98% of the control diet, respectively, and the two were not significantly different (P>0.05). Significantly better growth and efficiency in fish fed the whole body IAA profile diet than the unsupplemented diet suggests the crystalline amino acids were well utilized. However, a significantly lower (P<0.05) protein productive value in fish fed the whole body IAA profile diet relative to the fish meal control suggests pompano may benefit from coating the amino acids prior to dietary inclusion. A test diet incorporating casein at 200 g kg-1 dry diet and supplemented with crystalline amino acids to mimic the IAA ratio of the Florida pompano whole body is suitable for evaluating Florida pompano amino acid requirements.