Fermentation Of Asparagus And Effects Of Fermented Asparagus On Growth And Immunity Of Black Seabream

Gracilaria lemanerformis(GL)is another economic macroalage that has been artificially cultivated following laminaria and laver in china, with abundant phycobiliprotein, organic acids, minerals and other bioactive components, GL gets a balanced nutrients as a potencial aquatic animal feedstock. However, to date, studies have shown that the existence of antinutrient NSP in GL inhibits its maximum utilization of active substances, leading to a poor performance in aquatic animals. In order to improve the availability of GL based diet, for the first time, this experiment try to degrade asparagus with microbio, then applying the fermentation products into aquafeed.This study explored the optical fermentation technology of a marine bacteria ZC1 degrading asparagus and evaluated the use of fermentation products as a growth and immunity promoter for black sea bream, a comparision of influence has been made between asparagus and ferment asparagus, meanwhile, the suitable dosage of fermentation asparagus in black sea bream diet has also been figured out. Besides, an experient meal with 0.2% MOS and 10% asparagus is added to assess the effect of asparagus feed with MOS and fermentation asparagus with agaro-oligosaccharides on the performance of black sea bream.In the fermentation experiment, an agarolytic bacteria aquimarina agarilytica ZC1, isolated from the surface of marine red alga, is used to degrade asparagus. Analyzed with single factor and orthogonal experiment, the optimun culture medium composition was determined as: 3% asparagus, 10%ZC1, 2%Na Cl, asparagus particle size 40 mesh; and the optimum culture conditions were: p H7.6, culture temperature 25℃, rotation rate 180 r/min, culture time 70 h. Agaro-oligosaccharides consist 1.9% of the dried degradation products, whereas the proportion was 0.83% before fermentation.In the feeding trial, 7 isonitrogen and isoenergy(41% crude protein and 13.83KJ/kg total energy) test diets respectively containing 0(control), 5%, 10%, 15%, 20% dried ferment Gracilaria lemaneiformis(FGL) and 10% dried Gracilaria lemaneiformis(GL), 10%GL supplemented with 0.2%MOS were formulated for 630 black sea bream to value the effects of FGL on growth performance, biochemical composition, digestive and immune enzymes activities of the fish. Each treatment was randomly assigned to triplicate groups of 30 fish(initial weight 13.33g) in floating sea cages. After 60 days’ feeding experiment, the results can be briefly summarized as follows: WG, SUR and SGR of the fish fed with FGL diet were significantly higher, while FCR was significantly lower than that of control diet(P<0.05). The best SUR(97.78%), SGR(2.14), PER(2.15) and FCR(1.13) occur in fish fed with 5%FGL, higher level of FGL incorporation reduce fish performance. FGL meal varied the body composition of black sea bream by increasing body protein and decreasing muscle lipid in the fish. G2 diet group(contain 10% GL supplemented with 0.2% MOS) can also improve the SUR, FCR, body protein significantly. FGL meal can significantly increase pepsin activity and reduce intestine amylase activity than that of control group(P<0.05), fish reared with 10% FGL show the highest pepsin activity. T-AOC, GSH-Px, CAT and AKP activity in the serum and liver of black seabream fed with FGL diet promoted significantly, while no significant difference were observed in the activity of SOD, LZS, ACP in serum and LZS, ACP in liver. 10% GL significantly enhance the activity of CAT, AKP in serum and GSH-Px, SOD, T-AOC in liver. When the GL diet supplemented with 0.2% MOS, the CAT, T-AOC, AKP in serum and GSH-Px, TAOC in liver were obviously activated in comparison with control group.The expremental results indicated also that FGL diet does beneficial effects on the growth performance, immunity and antioxidant ability, incorporation of the FGL in the basal diet was feasible for black seabream. The benefit broght by FGL incorporation is better than that of GL incorporation. After adding 0.2% MOS to 10% GL diet, the growth performance and immune capacity of black bream surpass the control group and 10% GL group, but is inferior to 5% and 10% FGL diet group, which suggests that the growth and immunity promoting function of FGL may be a synergistic effect induced by agarooligosaccharides and other micromolecule bioactivator in FGL. The study may be a reference for the development of macroalage incorporation auqatic formula feed, and lay a foundation for further research of the agaro-oligosaccharides and algae active materials.