Use of agriculture byproducts in diets for pacific white shrimp Litopenaeus vannamei

Abstract

Eight Hawaii agricultural byproducts were tested for suitability in diets for Pacific white shrimp Litopenaeus vannamei. Two growth trials were conducted in a zero-water exchange system and two digestibility trials were conducted in a clear water system. A control growth diet in which fish meal (menhaden) was the single largest protein source (43.5% of total protein) was used in all trials. Ingredients that were rich in protein were incorporated in diets in replacement of fishmeal, while those low in protein replaced wheat. Meat and bone meal (MBM) at four levels of inclusion (7.4, 14.9, 22.3 and 29.7%), macadamia nut grit (MNG) at two levels of inclusion (15 and 30%) and spent fruit fly medium (FFW, 9.0%) were examined in Trial 1, and whole papaya (Whole Pap,10%), papaya flesh (Pap Flesh, 5%), papaya seed (Pap Seed, 10%), wheat mill run (WMR, 44.2%) and okara (soy pulp) (10 and 20%) were examined in Trial 2. All diets were formulated to contain 35% crude protein. Menhaden oil was adjusted to maintain the level of lipid in the diets at 9.5%. In Trial 2, a commercial diet (Rangen 35/2.5) was fed as an additional treatment. The diets were fed using automatic belt feeders on a 24-hour cycle to juvenile shrimp (Trial 1, 1.0 g; Trial 2, 1.5 g initial weight) for eight weeks in zero-water exchange outdoor seawater systems (1300 L volume). The final weight, growth and survival data from each trial were submitted to ANOVA procedures and the MBM data in Trial 1 to quadratic regression procedures, with a 5% error rate for significance.

In the Trial 1, the shrimp fed the MBM at 50% replacement of fish meal grew significantly slower and achieved a lower final weight than those fed the control diet. There were no other differences in growth. In Trial 2, the shrimp fed the commercial diet grew significantly slower and achieved a lower final weight than those fed the control diet, but there were no other differences among the other treatments. The feed conversion ratio data in Trial 2 did not reveal any differences among treatments, but were more variable, and therefore less powerful as an indicator of nutritional quality, than were the growth data.
In the digestibility trials, for apparent digestibility coefficient for dry matter (ADC-DM), Pap Flesh and Whole Pap had the highest levels of 68.5 and 71.4% respectively. For the crude protein apparent digestibility coefficients (ADC-CP) the FFW and MNG were the highest at 62.8 to 73.0%. Crude lipid apparent digestibility coefficients (ADC-CL) were highest for the MBM and MNG byproducts, 87.4 and 87.9% respectively. The Energy apparent digestibility coefficient (ADC-E) varied the greatest; FFW-first trial and Whole Pap levels were 61.7 and 68% respectively with Okara at the lowest level of 18.2%.
Based on these findings, it was concluded found that these agricultural byproducts can be included in diets for shrimp with little or no effect on growth under conditions of zero-water exchange.