The Use of Cyanobacteria Arthrospira platensis and Cladoceran Daphnia magna as Complementary Protein and Lipid Sources in Transitional Diet for Common Carp (Cyprinus carpio L.) Nursery

This study was conducted to evaluate the use of cyanobacteria Arthrospira platensis and cladoceran Daphnia magna biomass as complementary protein and lipid sources in diet supplementation for common carp (Cyprinus carpio L.) nursery. Three experimental diets containing A. platensis and D. magna meal at different concentrations were compared to the commercial (control) diet. Each experimental diet (ED) was set to contain D. magna and A. platensis meal at a specific combination: 2% and 5%, 2% and 7%, and 4% and 5% for ED1, ED2 and ED3, respectively. The protein and lipid content of the experimental diets ranged from 43.20% to 44.60% dry weight (DW) and 10.64% to 13.42% DW, respectively;while the protein and lipid content of the control diet were 43.00% DW and 6.72% DW, respectively. After 20 days of feeding period, ED3 group obtained the highest final body weight (BW) (58.18 ± 35.24 mg), total biomass (1936 ± 1625 mg), food conversion rate (1.34 ± 0.04), and specific growth rate (12.86 ± 0.03% BW day–1) among all treatment groups (P > 0.05);while ED1 group obtained the highest survival (75.5% ± 7.47%) among all treatment groups (P > 0.05). The total bacterial count and total pathogenic Aeromonas sp. in the culture water of the treatment groups (ranged from 2.00 to 2.65 × 105 CFU mL–1 and 3.50 to 4.12 × 103 CFU mL–1, respectively) were lower compared to the water of the control group fed (3.73 × 105 and 4.70 × 103 CFU mL–1, respectively). No significant differences in physicochemical water quality parameters were observed among treatments (P > 0.05). The current study suggests that the combination of A. platensis and D. magna biomass can be used as complementary protein and lipid sources in diet supplementation for common carp larvae and can result in a comparable fish growth, survival and feed utilization in common carp culture at the nursery phase.

Effects of dietary supplementation with tropical microfungi Mucor circinelloides and Trichoderma harzianum powder on growth performance,bacterial communities,and the biomass nutritional profile of white shrimp grow-out culture(Litopenaeus vannamei)

Microfungi have been explored further as supplement constituents in shrimp culture due to their rich protein,lipid,essential amino acids,fatty acids,and various bioactive compounds.The researchers have evaluated the effects of two microfungi powders(Mucor circinelloides and Trichoderma harzianum)as feed supplements on growth performance,bacterial communities,and the biomass nutritional profile of white shrimp(Litopenaeus vannamei).The results showed that commercial/artificial feed(Feng-Li)with supplementation microfungi powder had a different effect on white shrimp growth performance than control after 62 days of the grow-out period.Supplementation with 1.5%M.circinelloides powder(M-2)could improve the growth performance of white shrimp,especially the survival rate(81.33%),final body weight(5.21 g),and shrimp biomass(211.35 g).In contrast,supplementation with 1.5%T.harzianum powder(T-2)did not improve the growth performance of white shrimp compared to control(p>0.05).Furthermore,it also affected the profile of the bacterial community in culture water as well as in shrimp intestines.Supplementation with both microfungi could reduce the total number of bacteria in culture water at the end of the experiment,where the lowest number was obtained in treatment T-2(3.9×10^(5)CFU/mL),followed by M-2(9.9×10^(5)CFU/mL)and control(4.4×10^(6)CFU/mL).In the culture water,20 isolates of culturable bacteria were found during the trial,with the dominant bacteria in M-2:Bacillus cereus,Bacillus velezensis,Gordonia polyisoprenivorans,T-2:Acinetobacter sp.,Gordonia polyisoprenivorans,Micrococcus luteus.Based on average well colour development(AWCD),the highest bacterial activity was in the M-2(0.297-0.707),followed by T-2(0.226-0.717)and control(0.094-0.694).The highest substrate group utilised in M-2 and T-2 were polymers(0.896 and 1.348)and control:amines(0.100).The highest Shannon diversity index was obtained in the M-2(2.508),followed by control(2.286)and the T-2(2.157).As many as 11 isolates of culturable bacteria were found in the shrimp intestine,with dominant bacteria in M-2:Bacillus velezensis,Micrococcus luteus,Bacillus cereus,T-2:Bacillus velezensis,Micrococcus sp.2,Demequina activiva.The highest bacterial activity was in M-2(2.259),followed by control(2.020)and T-2(0.050).The highest substrate group utilisation was in M-2:polymers(2.564),T-2:carbohydrates(0.094),and control:polymers(2.185).The highest Shannon diversity index was in the M-2(3.234),followed by control(3.230)and the T-2(0.751).In addition,1.5%M.circinelloides and T.harzianum supplementation increased white shrimp muscle protein content up to 79.21%and 80.40%,respectively,compared to control(76.73%).In conclusion,using Mucor circinelloides powder as a feed supplement can improve the growth performance of white shrimp,increase the functional/probiotic bacteria:B.cereus and B.velezensis in cultur and shrimp’s intestine,and increase the protein content in shrimp muscle tissue.However,more in-depth research is needed,especially on anti-nutritional compounds from fungi that affect shrimp growth.