So conclude the authors of a new study who, over the course of an eight week feed trial, evaluated CSM as a protein source for partial replacement of soybean meal (SBM) with iron supplementation in diets of juvenile whiteleg shrimp (Litopenaeus vannamei).
Previous studies have been conducted to determine the level of SBM that can be replaced by CSM in diets of fish species including channel catfish, tilapia, grass carp, black carp and Chinese mitten crab (Eriocheir sinensis), white shrimp, and oriental river prawn. These previous results showed that SBM and CSM can be substituted at the same level and the animals do not show differences in weight gain, feed conversion ratio, and survival ratio; however, the apparent digestibility coefficients for dry matter, crude protein, and energy of CSM are lower than SBM, which was the main factor of limiting the use of CSM.
In the new study SBM protein was replaced with increasing dietary levels of CSM from 0 to and 100 percent, while ferrous sulfate supplementation ranged from 0 to 0.12 percent.
The researchers concluded that up to 90 percent of SBM could be replaced with CSM without causing a significant decrease (P < 0.05) in growth and feed utilisation in L. vannamei.
Related whole-body composition indexes (moisture, crude protein, crude lipid, ash) were significantly affected with the CSM level in the diets increased (P < 0.05). Regarding serum non-specific immune enzymes, phenoloxidase, acid phosphatase and alkaline phosphatase activities of shrimp were significantly decreased (P < 0.05) with the CSM level in the diets increased.
The researchers conclude that “the appropriate ratio of CSM for SBM replacement and ferrous sulfate supplement was 88.74 percent, which yielded the best growth and feed utilization. The total replacement of SBM with CSM could reduce the growth performance and immunity of L. vannamei.”
The full study, published in Aquaculture Reports under the title “Effects of replacing soybean meal with cottonseed meal on growth, feed utilization and non-specific immune enzyme activities for juvenile white shrimp, Litopenaeus vannamei” can be accessed here.