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Tilapia performance Tilapia is a popular warm water omnivorous fish produced for the consumer market. With an estimated 5.9 million metric tons produced in 2016 (Tacon, 2018), it is the second-most important farmed fish species after carp. Tilapia are well suited for aquaculture-based production systems as they are relatively disease resistant and able to utilize a wide variety of feedstuffs. Corn-based products including corn gluten meal and corn protein concentrate are used in tilapia feeding programs with considerable success. Flint Hills wanted to demonstrate to its customers that replacing some of the more-expensive protein products with NexPro was both economically and nutritionally viable. The studies created by our research partners examined the effects of the ingredient in tilapia diets at a variety of inclusion rates. First, preliminary research was conducted to attempt to determine maximum inclusion rates in tilapia diets. Diets were formulated to be equivalent in protein and lipid content, with lysine and methionine requirements met through the addition of crystalline amino acids as needed. The initial 56-day study indicated that with increasing inclusion, tilapia growth performance was numerically but not statistically improved as NexPro inclusion was increased (Fig. 1). Overall feed conversion ratios also did not differ among the different dietary treatments in this

experiment. The digestible energy content of NexPro was estimated at 98.3%, while the digestible protein content was estimated at 88.9% for tilapia. Subsequent research using NexPro as an ingredient in the diet of juvenile tilapia was presented by Amorocho et al., 2018. This nine-week feeding study involved replacing corn protein concentrate in low fishmeal diets. Corn protein concentrate, which contains 75% crude protein, was included in the basal diet at 8%. Treatment diets replaced the corn protein concentrate at 2% increments on an equal protein basis, resulting in 8%, 6%, 4%, 2%, and 0% c orn protein concentrate in the test diets. NexPro inclusion rates in the same treatment diets were increased from 0% to 3.15%, 6.30%, 9.45%, and 12.6% as corn protein concentrate was reduced. Tilapia were fed for nine-weeks starting at an average weight of 7.49 g. No differences were seen in any of the response variables, including final weight, weight gain percent, or feed conversion ratio. Therefore, we conclude that NexPro can replace other, more expensive high-quality protein ingredients in tilapia feed formulations.

Shrimp performance NexPro has been used in several Pacific white shrimp feeding studies. Most of these experiments have been aquarium based, with between ten and 30 post-larval

Figure 1. Growth performance of tilapia fed increasing levels of NexPro in the diet for 56 days.

Aquafeed: Advances in Processing & Formulation Vol 11 Issue 3 2019

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Aquafeed vol 11 issue 3 2019