Effect of Lemna minor supplemented diets on growth, digestive physiology and expression of fatty acids biosynthesis genes of Cyprinus carpio

Abstract

The potential nutritional value of duckweed Lemna minor (Lemnaceae) was evaluated for common carp Cyprinus carpio fry. Fish were fed diets containing five graded levels of duckweed: 0% (LM0, control), 5% (LM5), 10% (LM10), 15% (LM15) and 20% (LM20). The final weight and specific growth rate were significantly higher in LM15 and LM20 diets fed fish compared to others. Feed conversion ratio was minimum in fish fed diet LM20. Amylase activity was significantly higher in LM0 treatment. Total protease, trypsin and chymotrypsin activities showed linear relationships with the increased level of duckweed in the diet. Protein and essential amino acids contents were significantly higher in carp fed diets LM15 and LM20 compared to others. Lipid content was significantly higher in fish fed duckweed-based diets compared to control. A direct relationship was found between the inclusion level of duckweed in the diet and n-3 long-chain polyunsaturated fatty acid (LC-PUFA) content of carp. Contents of desaturated and elongated products of dietary linolenic acid (18:3n-3) including 20:4n-3, 20:5n-3, 22:5n-3 and 22:6n-3 increased in a graded manner with increasing dietary duckweed. The monounsaturated fatty acids and n-6 PUFA contents reduced significantly in fish fed duckweed. Expression of fads2d6, elovl2, elovl5 and fas were higher in carp fed diets LM10, LM15 and LM20 compared to control fish. The inclusion of L. minor in diet enhanced the nutritional value of carp by increasing protein, lipid, amino acids and n-3 PUFA contents.

Use of Coontail as a natural phytoremediation feed additive for common carp

“…In this study, the higher protein level results in increased body composition of fish due to the increase of aquatic macrophyte in the diets, whereas the rise in the C. demersum level reduced the lipid. In contrast, there was not only an increase in protein in common carp, but lipid contents also showed linear relationships (p < 0.05) with increasing the amount of duckweed included in the diet (Goswami et al 2022). Similarly, Rahmah et al (2022) revealed that the body composition of Pangasius catfish protein and lipid levels increased when using 10% Azolla cristata level in catfish diets.…”

“…However, the substitution of 33% C. demersum instead of wheat bran meal reduced the final weight by 10.6% and PER by 42.3% compared to the control group. Goswami et al (2022) aimed to determine the optimum dietary Lemna minor meal inclusion level in C. carpio diets. They reported that diets supplemented with duckweed had a positive effect on growth.…”

“…Azolla cristata protein grown in aquaculture wastewater can replace up to 10% fish meal protein in the diet of Pangasius catfish juveniles without negatively affecting feed intake, growth, survival, and body composition (Rahmah et al 2022). Goswami et al (2022) found that the inclusion of Lemna minor in the diet of carp enhanced the nutritional value of the carp by increasing protein, lipid, amino acids and n-3 PUFA contents in Cyprinus carpio fingerlings. Irabor et al (2022) found that a 40% inclusion level of Lemna minor meal in the diet for 56 days is best for optimum growth performance for juvenile C. gariepinus, with any negative effect.…”

Role of microbial phytases in improving fish health

“…The aquaculture industry is considered as the rapidly growing food‐producing sector in the world and has raised expectations of bridging the gap between fish demand and supply 4 . The development of aquaculture industry mainly depends on the supply of high‐quality feed for farmed fish 5 . Fishmeal is a commonly used protein source in aquafeeds because of its high protein content, excellent amino acid and fatty acids profile, vitamins, minerals, digestibility, palatability and low carbohydrate content 6 .…”

“…4 The development of aquaculture industry mainly depends on the supply of high-quality feed for farmed fish. 5 Fishmeal is a commonly used protein source in aquafeeds because of its high protein content, excellent amino acid and fatty acids profile, vitamins, minerals, digestibility, palatability and low carbohydrate content. 6 However, due to excessive use, rising fish production costs (40%-60%) and limited global supply of fishmeal, it must be replaced with a sustainable alternative source of protein such as the protein-rich plants.…”