| Tiger puffer has a long history of consumption in China and is an extremely high economic value mariculture fish.In 2020,China’s total production of puffer fish was 15,841 tons,including more than 5,000 tons of Tiger puffer.At present,the artificial breeding and breeding technology of Tiger puffer has been relatively mature,but there is still no specific high-efficiency full-price formula feed.The Lag of nutrition research has become a bottleneck in the sustainable development of Tiger puffer.In order to study the lipid metabolism of Tiger puffer,2 × 2 factors of lipid level ~*n-3 HUFA level were used to design feed,and the precise requirement of n-3 HUFA in feed was studied by Tiger puffer.The results showed that compared with the high lipid + low n-3 HUFA group,the Tiger puffer weight and weight gain rate of the high lipid + high n-3 HUFA group were higher(p < 0.05),the final weight gain increased by 25.04% by 1.05 g.But there was no difference between the two low lipid diets(p > 0.05).There was no significant difference in nutritional components of Tiger puffer muscle among the experimental groups(P > 0.05),but liver lipid,liver-to-body ratio,liver-to-body ratio and fatness degree had a tendency to change with the level of dietary lipid and n-3 HUFA.Changing the levels of lipid and N-3 HUFA in diet significantly affected the fatty acid composition of Tiger puffer liver and fish body(p < 0.05).Feeding high lipid diets increased fatty acid levels by 8.38% compared with low lipid diets.Feeding a high-lipid diet increased liver monoene levels by 2.25 per cent compared with low-lipid diets.Feeding High n-3 HUFA levels increased n-3HUFA levels in the body and liver by 1.30% and 3.31%,respectively,compared with low n-3HUFA levels.The relative expression of genes involved in lipid metabolism in the gut and liver of Tiger puffer showed that,the expression level of Tiger puffer Fatty acid synthesis gene(acac β,fas,hacd and scd1)in high lipid + high n-3 HUFA group was significantly lower than that in low lipid + high n-3 HUFA group(p < 0.05).The up-regulation of lipid transcription factors(srebf1,lxrα and pparα1)and fatty acid β-oxidation(cpt1,hsd17b4 and acox-3)genes in the low lipid +high n-3 HUFA group further indicated that,dietary lipid and n-3 HUFA levels have a significant interaction with growth and development of Tiger puffer.To sum up,the actual requirement of n-3 HUFA is related to the lipid level in the Tiger puffer feed,which is% TFA.The actual requirement of Tiger puffer for n-3 HUFA in feed should be defined as a percentage of total fatty acid content,and the precise requirement of Tiger puffer for n-3 HUFA in feed should be around 17.5% TFA.This means that the absolute level of n-3 HUFA needs to increase as the absolute level of lipid in the feed increases.The results of this study can provide reference and data support for the development of full-price formulated feed with high efficiency and specificity for Tiger puffer. |
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