Study on the Stability of Probiotic (Spirulina fusiformis) Incorporated Fish Diets

Aquaculture is one of the fastest-growing food production sectors in the world. The use of probiotics might be a good option to reduce the risk of disease and enhance fish productivity. Probiotics thus are opening a new era in the health management strategy for aquatic species including finfish and shellfish. Probiotics are beneficial microorganisms that help in maintaining the well-being of the host animal. The development of non-antibiotic and environment-friendly probiotic  feeds is one of the key factors for health management in aquaculture. The benefits of probiotic supplements include improved feed value, enzymatic contribution to digestion, and inhibition of pathogenic microorganisms. Feed stability is of paramount importance in the manufacture of aquaculture diets. The water stability of the feed pellet depends on the individual ingredients that bind together. Hence the study was designed to investigate the stability of probiotic feeds in water. Probiotic Spirulina added feed samples were soaked in a glass beaker containing water and allowed to remain for time intervals ranging from 10 to 60 minutes to study the stability of feed. The results showed that the control feed pellet (40.00 + 1.00) was the least stable among the types of experimental feed (SF2 and SF3) in 60 minutes of immersion. The increased level of stability (71.66 %) was recorded in (2 & 3% inclusion) feed type

Effect of wood apple<i style=""> Aegle marmelos</i>, Correa (Dicotyledons, Sapindales, Rutaceae) extract as an antibacterial agent on pathogens infecting prawn (<i style="">Penaeus indicus</i>) larviculture

156-161Aegle marmelos, an antimicrobial plant was extracted with 100% methanol and the sensitivity of the extract was assessed against different fish diseases caused by pathogenic bacteria. For sensitivity test, the minimal bacterial population growth (10-20 %) was observed in the 40 mg/100 ml concentration of the culture medium. Different concentrations (25,50,75 and 100 %) of the extracts were enriched with Artemia franciscana nauplii/pre-adult. These were fed to the Penaeus indicus post-larvae (6.5 to 6.85 mg of average weight) for 25 days, which were reared with four different pathogens (Pseudomonas aeruginosa, Aeromonas hydrophila, Salmonella typhi and Vibrio sp.) inoculated seawater. Among the four pathogens, P.aeruginosa was very sensitive to A. marmelos extract. Penaeus indicus post larvae fed on the un-enriched Artemia exhibited the lowest survival, which averaged 21 %, and this increased to the maximum of 58 % (averaged) in the 75 % extract enriched Artemia fed post larvae of P.indicus. Similarly, the weight gain and specific growth rate were also increased significantly (PArtemia fed post-larvae of P.indicus. Among the four different pathogens inoculated, the post-larvae, which were reared in the P.aeruginosa inoculation, exhibited the maximum survival (37.35 mg) and better growth rate (12.03 %). Also the bacterial count (cfu/g) was significantly (PArtemia fed post-larvae. The extract helped to reduce the bacterial count of a maximum of 1.9, 2.45, 0.96 and 2.36 times in the P.aerugiosna, A.hydrophila, S.typhi and Vibrio sp. respectively in the 100 % extract enriched Artemia fed post-larvae of P.indicus. Among the different percentages of enrichment, 75 % was considered the best for survival and growth characteristics of the post larvae

Zingiber officinalis an herbal appetizer in the tiger shrimp Penaeus monodon (Fabricius) larviculture

Penaeus monodon postlarvae were fed with different percentages (0%, 25%, 50%, 75% and 100%) of the herbal appetizer Zingiber officinalis enriched Artemia. After 30 days of culture (i.e. PL-1-30), a very positive result was found in Z. officinalis-enriched Artemia-fed postlarvae. The unenriched Artemia-fed postlarvae consumed 91.0 mg/animal/30 days of feed, whereas the Z. officinalis-enriched Artemia increased their consumption to 127.9 mg/animal/30 days. A similar pattern was noticed in feed absorbed (110.2 mg), dry weight growth (26.7 mg) and feed catabolized (83.2 mg) in Z. officinalis-enriched Artemia because of enzymatic activities. The conversion efficiency of unenriched postlarva was 17.19%, whereas in 100% Z. officinalis-enriched Artemia, the maximum conversion efficiency was 20.85%. The net production efficiency increased significantly (P &lt; 0.05) to 22% from that of the unenriched Artemia-fed postlarvae. The administration of Z. officinalis in all levels produced significantly (P &lt; 0.05) higher weight gain and specific growth rate. The utilization efficiency of feed increased proportionately to the percentages of Z. officinalis. Digestive enzyme activity (amylase, protease and lipase) increased significantly (P &lt; 0.05) in the 50%, 75% and 100% enrichment. Among the different percentages of enrichment, the 100% Z. officinalis-enriched Artemia-fed postlarvae performed better in the overall status.Penaeus monodon postlarvae were fed with different percentages (0%, 25%, 50%, 75% and 100%) of the herbal appetizer Zingiber officinalis enriched Artemia. After 30 days of culture (i.e. PL-1-30), a very positive result was found in Z. officinalis-enriched Artemia-fed postlarvae. The unenriched Artemia-fed postlarvae consumed 91.0 mg/animal/30 days of feed, whereas the Z. officinalis-enriched Artemia increased their consumption to 127.9 mg/animal/30 days. A similar pattern was noticed in feed absorbed (110.2 mg), dry weight growth (26.7 mg) and feed catabolized (83.2 mg) in Z. officinalis-enriched Artemia because of enzymatic activities. The conversion efficiency of unenriched postlarva was 17.19%, whereas in 100% Z. officinalis-enriched Artemia, the maximum conversion efficiency was 20.85%. The net production efficiency increased significantly (P < 0.05) to 22% from that of the unenriched Artemia-fed postlarvae. The administration of Z. officinalis in all levels produced significantly (P < 0.05) higher weight gain and specific growth rate. The utilization efficiency of feed increased proportionately to the percentages of Z. officinalis. Digestive enzyme activity (amylase, protease and lipase) increased significantly (P < 0.05) in the 50%, 75% and 100% enrichment. Among the different percentages of enrichment, the 100% Z. officinalis-enriched Artemia-fed postlarvae performed better in the overall status

Responses of fruit flies (Diptera: Tephritidae) to new attractants in Papua New Guinea

Male fruit fly attractants – cue-lure and methyl eugenol (ME) – have been used successfully for decades in the monitoring and control of species of Dacini (Dacinae) fruit flies (Bactrocera, Zeugodacus and Dacus). However, many species, including several pests, are non-responsive to these lures. Field tests of new compounds are therefore worthwhile, particularly in areas of high species diversity where multiple species attractions can provide additional information on lure function. Recent field tests of new male attractants (isoeugenol, dihydroeugenol, methyl-isoeugenol and zingerone) and food- and host-based lures (cucumber volatile blend and Cera Trap®) in Australia resulted in discoveries of lure responses for ‘non-responsive’ species. In this study, these new lures were field tested for the first time in Papua New Guinea (PNG) for attractiveness to ‘non-responsive’ species, including the guava pest Bactrocera obliqua and cucurbit pests Zeugodacus atrisetosus and Z. decipiens. Testing was conducted in the National Capital District (NCD) and Kerevat on the island province of East New Britain. Of the ‘non-responsive’ pest species, B. obliqua was trapped three times at isoeugenol and once at methyl-isoeugenol. This is the first record of B. obliqua responding to male lures. Zeugodacus decipiens was significantly attracted to Cera Trap. Five undescribed species responded to zingerone and one to the eugenol analogues. The ME-responsive B. musae and B. umbrosa responded differently to the three eugenol analogues in Kerevat and NCD, with both species responding more strongly to methyl-isoeugenol in NCD, although their response to ME was similar in both locations. Intraspecific differences in lure response were also noted between this study and that recorded previously in other countries. The cue-responsive B. frauenfeldi, B. neohumeralis and Dacus axanus were previously trapped at zingerone in Australia, and the ME-responsive B. dorsalis was trapped at zingerone in Malaysia, but these species, while caught at their respective lures, were not recorded at zingerone in this study. The findings from this study have implications for quarantine monitoring for the ‘non-responsive’ B. obliqua and Z. decipiens in Australia, highlight that there may be intraspecific variation in male lure response and provide further information on these novel male lures' activity