Various studies have highlighted the potential of corn gluten meal as an important plant-based protein alternative to replace fish meal in levels ranging from 15% to 75%, without affecting the growth performance and feed utilization in some aquaculture species.
Several studies have reported the replacement of fish meal with corn gluten meal in the feeding of Malaysian giant shrimp and white shrimp. However, the effect of this replacement on growth and feed utilization, as well as the digestibility, has not been adequately evaluated.
In this regard, researchers from the College of Fisheries at Guangdong Ocean University, the Aquatic Animals Precision Nutrition and High Efficiency Feed Engineering Research Center of Guangdong Province, the Guangdong Provincial Key Laboratory of Aquatic Animal Disease Control and Healthy Culture, and the Institute of Animal Nutrition at Sichuan Agricultural University evaluated the effects of replacing fish meal with corn gluten meal on the growth of juvenile Litopenaeus vannamei shrimp and the apparent nutrient digestibility.
The experiment replaced fish meal (30% in the control group) with corn gluten meal at levels of 0, 10, 20, 30, 40, and 60%.
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The researchers report that the study results showed no significant differences in weight gain rate (WGR), feed conversion ratio (FCR), and specific growth rate (SGR) of the shrimp after replacing 30% of fish meal with corn gluten meal.
However, these indicators decreased significantly when fish meal replacement exceeded 30%.
“Therefore, a higher replacement of fish meal with corn gluten meal will have an effect on the growth of L. vannamei, which could also be a key reason for a significantly higher FCR,” they reported.
Based on the results, the researchers recommend an optimal level of fish meal replacement with corn gluten meal in vannamei shrimp diets of 27.47%.
With the increase in corn gluten meal content, the crude protein and phosphorus content in the shrimp significantly decreased, while the crude fat content initially increased significantly and then decreased.
Digestive enzyme activity is an important indicator of animal digestive function, determining their capacity to digest nutrients, which in turn affects growth and development.
Thus, digestive enzyme activity determines the shrimp’s ability to digest and absorb nutrients, with higher enzyme activity indicating greater digestive capacity.
“Compared to the control group, the protease activity was significantly lower in the 40% group, and the lipase activity was significantly lower in the 60% group,” they reported.
According to the researchers, amylase activity significantly increased with the increase in corn gluten meal levels.
“The digestibility of protein and lipids was significantly reduced by replacing corn gluten meal with more than 30% of fish meal,” they informed.
The researchers conclude that fish meal can be partially replaced by corn gluten meal in the feeding of vannamei shrimp.
“Based on the WGR regression analysis, the optimal replacement level of corn gluten meal was 27.47%,” they concluded.
The study was funded by the National Key Research and Development Program, Innovation and Entrepreneurship Training Program for College Students, Undergraduate Innovation Team of Guangdong Ocean University, and Postgraduate Education Innovation Project of Guangdong Ocean University
Reference (open access)
Lin H, Deng Y, Zhu D, Yang Q, Zhou X, Tan B, Feng L and Chi S (2023) Effects of partially replacing fishmeal with corn gluten meal on growth, feed utilization, digestive enzyme activity, and apparent nutrient digestibility for juvenile white shrimp, Litopenaeus vannamei. Front. Vet. Sci. 10:1162599. doi: 10.3389/fvets.2023.116259