Effects of Ultra-fine Pulverized Mulberry Leaf Combined with Multi-enzyme Preparations on Lipid Metabolism in Serum, Liver, Muscle and Intestine of Grass Carp

ABSTRACT:

Grass carp are prone to excessive fat deposition under intensive aquaculture conditions, which impairs their health and reduces the economic benefit of farmed carp. We investigated the effects of dietary ultrafine pulverized mulberry leaf on lipid metabolism in grass carp, using phenotypic indicators and multi-omics approaches. A total of 480 grass carp (8.45 ± 0.17 g) were randomly divided into three groups (4 replicates per group, 40 fish per replicate). After 24 h of fasting, the fish were fed a basal diet (CK) and two experimental diets supplemented with either 6% or 12% ultrafine pulverized mulberry leaf and multi-enzyme preparations for 60 d. The results showed that serum triglyceride (TG) content decreased with increasing mulberry leaf supplementation, whereas intestinal lipase activity increased in a dose-dependent manner. Compared with the CK group, the mulberry leaf groups reduced the levels of serum total cholesterol (TC), high-density lipoprotein cholesterol (HDL-C), and low-density lipoprotein cholesterol (LDL-C), while decreasing the activity of glutathione peroxidase (GSH-Px) and superoxide dismutase (SOD). Malondialdehyde (MDA) content increased in the 6% group, whereas both total antioxidant capacity (T-AOC) and MDA content decreased significantly in the 12% group. The mulberry leaf groups showed increased dorsal muscle pH and reduced centrifugal loss and ether extract (EE) content. The 12% group had lower Opto value and crude protein (CP) content than the 6% group and the lowest muscle shear force. In terms of the dorsal muscle fatty acid composition, compared with the CK group, contents of unsaturated fatty acid (UFA), polyunsaturated fatty acid (PUFA), ω-3 PUFA, and ω-6 PUFA decreased in the 6% group but increased in the 12% group. Meanwhile, monounsaturated fatty acid (MUFA) showed the opposite trend; the 6% group had the lowest saturated fatty acid (SFA) content. The mulberry leaf groups showed downregulated expression in the liver of genes involved in glycolysis (gk, pfk, pk) and lipogenesis (fas, acc), and all genes except pk showed a dose-dependent decrease with increasing mulberry leaf supplementation. Intestinal omics analysis revealed that the lysine degradation pathway is a key pathway regulating lipid metabolism in ultrafine pulverized mulberry leaves. The reduced levels of multiple differential metabolites and the enhanced microbial metabolic functions (especially amino acid and lipid metabolism) were closely associated with the inhibition of lipid metabolism in grass carp. This study indicates that ultrafine pulverized mulberry leaves effectively inhibit lipogenesis and reduce lipid deposition in grass carp by regulating the gut microbiota-metabolite-liver axis, providing a theoretical basis for the development of functional feed comprising mulberry leaf. A supplementation level of 12% ultrafine pulverized mulberry leaves is recommended.

INSTRUMENT(S): Liquid Chromatography MS - negative - reverse-phase, Liquid Chromatography MS - positive - reverse-phase

PROVIDER: MTBLS13847 | MetaboLights | 2026-10-15

REPOSITORIES: MetaboLights