全脂黑水虻幼虫粉替代鱼粉对大菱鲆养殖性能、生理代谢及体色的影响

Effects of Replacement of Fish Meal with Full-Fat Hermetia illucens Larvae on Culture Performance, Physiological Metabolism, and Skin Color in Turbot

中文关键词: 大菱鲆  黑水虻虫  生长  血清生化指标  体色

英文关键词: Turbot  Hermetia illucens  Growth performance  Serum biochemical indexes  Skin color

中文摘要:

      以大菱鲆(Scophthalmus maximus)为研究对象，探讨其配合饲料中以全脂黑水虻(Hermetia illucens)幼虫粉替代鱼粉后对大菱鲆生长性能、饲料利用、血清生理生化指标及体色的影响。本研究设计4个处理组，分别为全脂黑水虻幼虫粉替代0(FM)(对照组)、20%(HI20)、40%(HI40)的鱼粉及40%替代后添加晶体赖氨酸(Lys)和蛋氨酸(Met)(HI40AA)形成4种等氮、等能的实验饲料。将1200尾大菱鲆幼鱼[(26.57±0.54) g]随机分为4组，每组3个重复，每个重复100尾鱼，实验时间为56 d。结果显示，黑水虻幼虫粉替代鱼粉显著影响了大菱鲆的相对增重率(WGR)和特定生长率(SGR)，HI40和HI40AA组显著低于HI20和FM组(P<0.05)，对大菱鲆的摄食率(SR)、饲料系数(FCR)、肝体比(HSI)、脏体比(VSI)、肥满度(CF)及体成分中的粗蛋白、粗灰分含量均无显著影响(P>0.05)，FM和HI20组大菱鲆血清总胆固醇(TCHO)及高密度脂蛋白(HDL)含量显著高于HI40和HI40AA组(P<0.05)，FM组低密度脂蛋白(LDL)含量显著高于各替代组(P<0.05)；HI40和HI40AA组大菱鲆背部体色L*值、a*值显著低于FM和HI20组(P<0.05)，FM组背部体色b*值显著低于其他各实验组(P<0.05)，HI40组的b*值显著高于HI20和HI40AA组(P<0.05)；大菱鲆腹部的体色参数各实验组相比无显著差异(P>0.05)。研究表明，本研究条件下，全脂黑水虻幼虫粉替代大菱鲆饲料中鱼粉为20%时，不会影响大菱鲆的生长与生理功能，其在大菱鲆幼鱼饲料中的鱼粉替代推荐量为20%。

英文摘要:

      Turbot (Scophthalmus maximus) is an important mariculture species in northern China because of its high economic value. As a cold-water carnivorous fish, its rapid growth relies on high dietary protein in the form of fish meal. Fish meal is a major component of aquatic feed because of its highly digestible protein, balanced amino acids, and good palatability. However, global fish meal production is insufficient, and its price has soared due to overfishing and climate change. There is an urgent need to find high-quality protein sources to replace fish meal in the diet. Many experimental studies on replacing fish meal with protein sources have identified shortcomings. Plant protein sources contain anti-nutritional factors and defects in the amino acid profile, and have poor palatability; animal protein sources are unstable in their nutrient composition. Much work remains to be done to identify new protein sources. Insects are the largest organism community in ecosystems, and offer a new kind of protein source with great potential. The European Commission has recently approved the use of protein derived from insects in aquatic feed. Hermetia illucens is a saprophytic insect that can consume livestock manure and domestic waste to produce high-value animal feedstuff. Its larvae can be used as an alternative protein source to fish meal because they are rich in amino acids and polyunsaturated fatty acids. In addition, H. illucens is fed on decaying organic matter such as food waste, animal excrement, and animal and plant carcasses; the breeding cost is low, and the adults do not disturb humans. It can be added to the feed of sea bass (Dicentrarchus labrax), rainbow trout (Oncorhynchus mykiss), catfish (Pelteobagrus fulvidraco), large yellow croaker (Larimichthys crocea), grass carp (Ctenopharyngodon idellus), california bass (Micropterus salmoides), and Scophthalmus maximus (turbot). Most research has investigated the defatted dry powder of H. illucens. However, there are no reports on the replacement of fish meal with full-fat H. illucens in turbot. Therefore, in this study, we aimed to evaluate the application of H. illucens larvae as turbot feed. This experiment was conducted to investigate the effects of replacement of fish meal protein with full-fat H. illucens larvae meal on the growth performance, feed utilization, serum biochemical indexes, and skin color of turbot, in order to provide important information for turbot culture. Four treatments were designed for this study. Four isonitrogenous and isoenergetic diets were formulated with H. illucens larvae meal by substituting it into fish meal at 0% (FM), 20% (HI20), and 40% (HI40); the fourth experimental diet (HI40AA) was HI40 supplemented with methionine and lysine. A total of 1200 turbot [initial body weight: (26.57±0.54) g] were randomly distributed into four experimental diets, each group with three replicates, and each replicate with 100 juvenile turbot. The fish were fed twice daily to apparent satiation. The water temperature was kept at 11.0℃~14.4℃ and the water was changed twice daily. After the 56 d feeding trial, the results showed that H. illucens larvae meal significantly influenced weight gain and specific growth rate, which were significantly lower in the HI40 and HI40AA groups than in the HI20 and FM groups (P<0.05); no significant differences were observed in the feeding rate, feed conversion ratio, hepatosomatic index, viscerosomatic index, condition factor, or body composition, including crude protein and ash, among all groups (P>0.05). The serum cholesterol and high-density lipoprotein in the HI40 and HI40AA groups were significantly lower than those in the HI20 and FM groups (P<0.05), and the content of serum low-density lipoprotein in the FM group was significantly higher than that in the other groups (P<0.05). The values of L* (lightness) and a* (redness) of turbot dorsal skin color in the HI40 and HI40AA groups were significantly lower than those in the FM and HI20 groups (P<0.05). The value of b* (yellowness) of turbot dorsal skin color in the FM group was significantly lower than those in the other groups (P<0.05); it was higher in the HI40 group than in the HI20 and HI40AA groups (P<0.05). No significant differences were observed in skin color parameters in the ventral area of the turbot (P>0.05). In conclusion, the replacement of dietary fish meal with H. illucens did not affect the growth performance and physiological parameters of turbot when the replacement level was no more than 20%, which is therefore the recommended substitution level of fish meal by full-fat H. illucens larvae meal in the diet of juvenile turbot.