Effects Of Supplementation Microcapsule Or Crystalline Methionine In Diets With Low Fish Meal On Growth Performance, Of Cobia (Rachycentron Canadum) And Pacific White Shrimp (Litopenaeus Vannamei)

The present study was conducted to compare the effects of microcapsule methionine with crystalline methionine in diets with low fish meal on growth performance, protein metabolism and digestive enzyme activities of cobia (Rachycentron canadum) and Pacific white shrimp (Litopenaeus vannamei). The study contained three sections: 1. Processing and technique for microcapsule methionine. 2. Effects of supplementation microcapsule or crystalline methionine on growth performance in diets with low fish meal of cobia. 3. Effects of supplementation microcapsule or crystalline methionine on growth performanc of Pacific white shrimp in dietw with low fish meal. The results were presented as follows:1. The methionine microcapsules were prepared with emulsification and fluid bed (Wurster). Uniform design experimentation was used to filtration the correlative parameters of emulsification method. Drug loading of gelatin microcapsule by this method was 46.94% and the pellets diameter was bigger. Cellulose-acetate- phthalate (CAP), acrylic resin (RES) and tripalmitin (TPA), as the main wall materials, respectively, were used in fluid bed (Wurster) method. Drug loading of the microcapsules with smooth wall and uniformity diameter was between 60-70% by regulating air temperature of input and output, velocity of peristaltic pump, coating time and pulverization press and so on.According to drug loading, methionine microcapsules made by fluid bed were evaluated for leaching loss. One experiment was conducted to investigate the leaching loss of diets supplied coated methionine and crystalline methionine and soaked in seawater and pH value of seawater at 10min, 20min, 30min, 60min and 90min, respectively. Five experiment diets were designed with methionine supplementation in the forms of L-methionine (MET, as control), Methionine hydroxy analogue (MHA), cellulose-acetate-phthalate (CAP), tripalmitin-polyvinyl alcohol (TPA) and acrylic resin (RES) coated L-methionine, respectively. The results showed leaching loss of methionine increased with increasing soaking time. Leaching loss of methionine of RES group was significantly lower than that of MET group. The pH value descended with increasing soaking time. CAP and RES groups dropped slowly in pH value. Leaching loss of methionine had negative correlation with pH value of seawater. In conclusion, acrylic resin was the better wall material than the others to retard leaching loss of methionine.2. Seven iso-nitrogen and iso-energy diets, including fish meal (positive control), low fish meal (negative control) and five methionine supplemented with MET, MHA, CAP, RES and TPA, respectively, were prepared to investigate utilization of coated and crystalline methionine in intestine of juvenile cobia. Each treatment was randomly assigned to triplicate groups of 20 fish (initial weight 5.40±0.07 g) per aquarium. Fish were maintained in flow-through aquaria for 8 weeks at water temperature ranged from 29 to 31℃.The results showed that weight gain and specific growth rate of fish fed RES was the highest in methionine supplementation groups and significantly higher 23.64% and 7.99% than that of negative group (P<0.05). Protein efficiency ratio of fish fed MET was significantly higher than negative control and the other methionine supplementation groups (P<0.05), and that feed conversion ratio of fish fed MET was significantly lower than that of the others (P<0.05). Condition factor of fish fed methionine had no significant difference with positive control (P>0.05). Crude protein contents and rate of methionine to essential amino acid (A/E) in muscle of fish fed microcapsule and crystalline methionine groups had no significant difference with positive control (P>0.05). Trypsin activities of intestine of fish fed microcapsule methionine were significantly higher than that of fed crystalline methionine and the positive control (P<0.05). Compared to positive group, fish fed the diet with RES had no significant difference in pepsin activities, whereas significantly higher than other groups (P<0.05). After feeding 0.5h, Na+, K+-ATP activities in intestine of fish fed MET were significantly higher than that of the other groups (P<0.05). After feeding 3h, Na+, K+-ATP activities of fish fed RES and positive control ascended and was higher than that of fish fed CAP and MHA, and that activities of fish fed positive control and microcapsule methionine were significantly higher than that of MHA and MET after feeding 8h(P<0.05).One feeding frequency trial was conducted in order to validate the rates of absorption in intestine of juvenile cobia and explore the difference in absorption of crystalline methionine, RES microcapsule and amino acid of intact protein (Control). Cobia were fed a commercial pelleted feed in feeding frequency 2 (at 0800 and 1600 hours), 3 (at 0800, 1200 and 1600 hours), 4 (at 0800, 1100, 1400 and 1600 hours), and 5 times day-1 (at 0800, 1000, 1200, 1400 and 1600 hours), respectively, the control was fed 2 timesday-1 only. Each treatment was randomly assigned to triplicate groups of 20 fish (initial weight 5.40±0.07g) per aquarium. Fish were maintained in flow- through aquaria for 4 weeks at water temperature ranged from 29 to 31℃. Weight gain was increased with increasing feeding frequency. Fish fed with RES 5 times day-1 was significantly higher than the others (P<0.05). Condition factor of fish fed 3 times day-1and fed RES 2 times day-1 were not different from the control (P>0.05). Total protease activities in liver of fish fed MET 3 times day-1 and amylase activities in intestine of fish fed RES 3 times day-1 were significantly higher than the others (P<0.05). Pepsin activities of fish fed MET were significantly higher than RES with 2 times day-1 and 5 timesday-1 (P<0.05). GOT/GPT of fish fed MET ascended with increasing feeding frequency, whereas GOT/GPT of fish fed RES 4 times day-1 was higher than the others (P<0.05).3. This study was conducted to evaluate the effects of methionine supplementation form in diets of Pacific white shrimp (Litopenaeus vannamei) on growth performance, feed utilization and digestive enzyme activities at day 14, 28 and 50. Five iso-nitrogen and iso-energy diets were prepared in which three diets were supplemented with cellulose-acetate-phthalate (CAP), tripalmitin-polyvinyl alcohol (TPA) and resin (RES) coated L-methionine, respectively. Hydroxyl-methionine calcium (MHA) was supplemented as the fourth diet and crystalline L-methionine diet (MET) was used as the control. Five triplicate groups of shrimp (0.81±0.01g in initial body weight) were fed each test diets for 7 weeks. Leaching test showed that RES coating had the better effects in reducing leaching loss of crystalline methionine in feed. Protein efficiency ratio, weight gain and specific growth rate of shrimp fed MET and RES were significantly higher than CAP and MHA (P<0.05) and MET was higher than RES without difference (P>0.05). Feed conversion ratio (FCR) of shrimp fed MET were significantly lower than CAP and MHA (P<0.05) at day 28. At day 50, weight gain of shrimp fed MET and RES were significantly higher than that of the others (P<0.05), while FCR of shrimp fed RES was significantly lower than the others (P<0.05). Weight gain, PER and SGR of shrimp fed RES were found.56%, 8.63% and 2.19% than without significant differences with the others. Crude protein of shrimp body in RES and TPA was markedly higher than the others (p<0.05). Methionine contents in muscle of RES and MHA groups were significantly higher than those of MET group, which had the lowest lysine contents (p<0.05). At day 28, after fed 0.5h, MAT activity in hepatopancrease of shrimp fed CAP was the highest, MAT activity of shrimp fed TPA was constantly low level after feeding 0.5h and 1h and rose after fed 3h. MAT activity of shrimp fed MET was low at 0.5h, 3h and 6h, but rose the highest at 12h. At day 50, MAT activities at 1h of shrimp fed microcapsule methionine climbed compared with 0.5h, at the same time, climb of MAT activity of shrimp fed RES was slowness, whereas MET dropped. After feeding 3h, MAT activity of shrimp fed RES was the highest. Total protease activity was increased at day 50 compared with day 28, and shrimp fed TPA was significantly higher than RES (p<0.05). Shrimp fed MET had significantly higher lipase activity than the others (p<0.05) and lower amylase than microcapsule methionine groups without difference (P>0.05). Apparently digestibility for protein of shrimp fed MET was significantly higher than the others at day 28, however, lower than RES without difference. Apparently digestibility for lipid of shrimp fed RES was significantly higher than that of shrimp fed MET (P<0.05).One feeding frequency trial was conduted in order to validate the rates of absorption in hepatopancrease of Pacific white shrimp and explore the difference in absorption of crystalline methionine, RES microcapsule and amino acid of intact protein (positive control, fish meal group and negative control, methionine deficiency). Shrimp were fed a commercial pelleted feed, fed in feeding frequency 2 (at 0700 and 2100 hours), 4 (at 0700, 1200, 1800 and 2100 hours), and 6 timesday-1 (at 0700, 0930, 1200, 1500, 1800 and 2100 hours), the positive control and negative control were fed 4 times day-1 only. Each treatment was randomly assigned to triplicate groups of 30 shrimps (initial weight 1.27±0.01 g) per aquarium. Shrimps were maintained in aquaria for 5 weeks at water temperature ranged from 29 to 30℃. Shrimp fed MET or RES had no different differencs in weight gain, SGR and PER with the same feeding frequency. Weight gain of shrimp fed RES 6 times day-1 had no difference with positive control (P>0.05). FR and FCR of shrimp fed RES was lower than MET (P>0.05) at the same feeding frequency. Crude protein contents of shrimp body of shrimp fed MET 6 times day-1 were significantly higher than that 4 times day-1 (P<0.05). Total protease activities of shrimp fed RES 4 times day-1 were the highest, which was no difference with positive control (P>0.05). GOT activities of shrimp fed MET 2 times day-1were significantly higher than 4 and 6 times day-1, and that significantly lower than positive control (P<0.05).In conclusion, supplementation methionine in diets with low fish meal could improve utilization of soybean meal and meat and bone meal and promot growth of juvenile cobia and Pacific white shrimp. On the basis of weight gain, free methionine could be used for growth for juvenile cobia and Pacific white shrimp in short term, however, on the basis of metabolize enzyme activities, RES microcapsule not only had the better delay release in alimentary tract but also reduced leaching loss in seawater, which enhanced methionine utilization and protein synthesis. It is necessary to improve processing and technique of RES microcapsule further and choose feasible substituted ratio between fish meal and other protein sources for the best growth of fish and shrimp.