Page 172 - 《水产学报》2026年第2期

2 期 莫子颖，等：饲料 SFA/MUFA 比对尼罗罗非鱼生长性能、组织脂肪酸组成和肝脂代谢的影响 50 卷

Effects of dietary SFA/MUFA ratio on growth performance, tissue fatty acid
composition and liver lipid metabolism of Oreochromis niloticus

MO Ziying , HUANG Xiaoping , GUAN Junfeng , XU Chao , LI Yuanyou , XIE Dizhi *
(College of Marine Sciences, South China Agricultural University, Guangzhou 510642, China)

Abstract: Oreochromis niloticus is one of the most important freshwater farmed fish species globally. Enhancing its muscle
quality, particularly the content of n-3 long-chain polyunsaturated fatty acids (n-3 LC-PUFAs) and its overall texture, is benefi-
cial in meeting consumer health demands and increasing product value-added. Feed is a key factor regulating the growth and
muscle nutrient composition of farmed fish. The saturated fatty acids (SFA) and monounsaturated fatty acids (MUFA) it con-
tains play vital roles in fish growth and the n-3 LC-PUFA sparing effect. Therefore, to investigate the optimal dietary
SFA/MUFA ratio for O. niloticus, we formulated four isoproteic (30% crude protein) and isolipidic (7% crude lipid) experi-
mental diets. These diets (T1-T4) had SFA/MUFA ratios of 0.31, 0.52, 0.97, and 1.52, respectively, and were formulated using
soybean oil, rapeseed oil, and beef tallow as lipid sources. Juvenile O. niloticus (initial body weight: 5.0 g) were fed these diets
for 9 weeks. No significant differences were observed in growth performance, feed conversion ratio, whole-body proximate
composition, serum LDL-C, MDA levels, or T-AOC capacity among the groups. However, serum HDL-C, T-CHO, and TG
levels increased with higher dietary SFA/MUFA ratios. Regarding muscle quality, the hardness, chewiness, and springiness of
muscle in the T1 and T2 groups were significantly improved compared to the T3 and T4 groups. In terms of lipid metabolism,
the n-3 LC-PUFA content in the liver and muscle was highest in the T1 group, although the mRNA expression levels of key LC-
PUFA biosynthesis-related genes (fads2 and elovl5) in the liver showed no significant differences across groups. Additionally,
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the cytoplasmic NAD /NADH ratio significantly decreased with increasing dietary SFA/MUFA ratios. Notably, the expression
levels of fatty acid catabolism-related genes (aco-x1 and cpt-1a) and synthesis-related genes (fas and acc) in muscle reached
their maximum in the T1 group. In conclusion, a dietary SFA/MUFA ratio of 0.31 enhances muscle fatty acid nutrition and tex-
ture quality in O. niloticus. The improved tissue n-3 LC-PUFA levels are likely due to the "n-3 LC-PUFA sparing effect" facil-
itated by a low SFA/MUFA ratio in the diet rather than enhanced endogenous LC-PUFA biosynthesis. These findings provide
novel insights into optimizing dietary fatty acid strategies for cultivating high-quality O. niloticus.
Key words: Oreochromis niloticus; dietary SFA/MUFA; growth performance; tissue fatty acids; liver lipid metabolism
Corresponding author: XIE Dizhi. E-mail: xiedizhi@scau.edu.cn

Funding projects: Guangdong Basic and Applied Basic Research Foundation (2024A1515030246)

中国水产学会主办 sponsored by China Society of Fisheries https://www.china-fishery.cn
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