Effects of using Artemia urmiana enriched with N-3 HUFA in first feeding of rainbow trout (Oncorhynchus mykiss) larvae

Effects of using n-3 HUFA-enriched Artemia and non-enriched Artemia as the starter food for growth and survival of rainbow trout larvae compared to commercial concentrated food were investigated in this study. The larvae with average weight of 92.9 mg were fed for 20 days with four food treatments included of commercial concentrated food, newly hatched Artemia, enriched Artemia, and mixture of enriched Artemia and concentrated food. At the end of experiment, the highest weight gain percentage was 104.4% in those larvae fed with enriched Artemia (p< 0.05). The highest survival rate was 96.5 % observed in larvae fed with mixture of enriched Artemia and commercial concentrated food (P<0.05). Larvae of third treatment that were fed with enriched Artemia with a survival rate of 98.9 %±1.9 under stress condition of low pH and survival rate of 66.5%±3.7 under stress condition of higher pH in rearing environment, were the most resistant larvae against stress resulting from pH fluctuation (P<0.05). Meanwhile the highest resistance against stress, resulting from temperature changes, was seen in larvae of the third and fourth treatment with survival rate of 77.8% at 24°C respectively

Apparent lipid and fatty acid digestion, retention of lipid and growth performance in Caspian salmon (Salmo trutta caspius) fry fed dietary n-3 highly unsaturated fatty acids and vitamin E

A 10-week feeding experiment was conducted to investigate the effect of dietary n-3 highly unsaturated fatty acids (n-3 HUFA) and vitamin E interaction on growth, apparent digestibility, apparent retention and utilization of lipid in Caspian salmon fry. Six experimental diets combining three different dietary levels of n-3 HUFAs (L: low: 1+0.5, DHA+EPA, M: medium 2+1, DHA+EPA, H: high 4+2 DHA +EPA g/100g diet) with two different levels of vitamin E (L: low 300 and H: high 1000 mg/kg diet): LL, LH, ML, MH, HL and HH (HUFA/vitamin E) were investigated. Fry with initial mean (±SD) body weight of 600 ± 25 (mg) were randomly distributed in tanks and fed to apparent satiation. Increase in dietary HUFA and vitamin E markedly improved larval growth. The results showed that the survival of Caspian salmon fry was not affected by dietary omega-3 HUFA and vitamin E. C20:5n-3 and C22:6n-3 fatty acids content of polar and neutral lipids positively correlated with their concentration on diets. Apparent digestibility and apparent retention of total lipid was significantly affected by dietary HUFA. The results showed that n-3 highly unsaturated fatty acids and vitamin E had positive effects on growth performance, lipid metabolism and apparent digestibility of Caspian salmon fry

Effected by dietary nucleotide on changes in intestinal Morphology, growth and fatty acid profile of whiteleg shrimp (Litopenaeus vannamei)

The effects of dietary nucleotide (0.2%) on the growth, intestinal morphology as well as fatty acid profile of the whiteleg shrimp, Litopenaeus vannamei was investigated in Bushehr province (Delvar) for a 5-week feeding trial. The experiment was carried out in triplicate in circular PVC tanks of 300L capacity. Each tank was randomly filled with 25 shrimps weighting on average 3.21±0.03g. Added dietary nucleotide significantly improved growth factors such as 10% weight increase, 7.97% increase in specific growth rate (SGR), 11.32% increase in protein efficiency ratio (PER), 9.64% decrease in feed conversion ratio (FCR) and 14:1n5, 20:3n3 and DHA fatty acids. However, no significant differences were evident in survival, carapace length gain, daily feed consumption and saturate fatty acid (SFA), monounsaturated fatty acid (MUFA), poly unsaturated fatty acid (PUFA) content, n-3/n-6 as well as EPA+DHA fatty acids between the two treatments. Intestine epithelium cells height (IECH) in the abdominal first section were significantly higher in shrimp fed by dietary nucleotide

Interactions of dietary selenium and fat on fatty acid compositions of rainbow trout (Oncorhynchus mykiss) tissues

The main objective of this study was to determine the interactive effects of dietary selenium and fat on fatty acid compositions of rainbow trout tissues. We formulated six experimental diets by addition of two fat levels (15 and 30%) and three selenium levels (0.1, 0.15 and 0.2mg/kg) to a basal diet, according to a 3x2 factorial design. Juvenile rainbow trout with initial weights of 6.99g were assigned to 18 tanks with 300L capacity each containing 25 fish, with three replicates for each diet. The result showed that unsaturated fatty acid and tissue oxidation rate increased with an increase in fat content of the diets. Addition of dietary selenium increased enzyme of Glutathione (GSH-Px) activity and at high-fat diet (30% fat), selenium addition improved polyunsaturated fatty acid compositions by depression of oxidation rate. However, inclusion of high dose of selenium (0.2mg/kg) had a negative impact on the Arachidonic and Eicosapentaenoic acids. In conclusion, dietary selenium supplementation can preserve fatty acid quality by controlling fatty acid oxidation at high-fat diet. The results obtained from the current study suggest that rainbow trout at high-fat diet requires 0.15mg/kg selenium to reduce oxidation level

Changes of digestive enzymes activity in common carp (Cyprinus carpio) during larval ontogeny

This study was aimed to gain knowledge on the ontogeny of digestive enzymes in common carp larvae at the governmental Warm Water Fish Aquaculture Center of Shahid Rajaee in Sari, Mazandaran, Iran. The ontogenetic development of pancreatic (trypsin, chymotrypsin, lipase and α-amylase) and intestinal (alkaline phosphatase and aminopeptidase-N) enzymes were assessed in common carp larvae from first feeding (3 days post hatching) to 33 days post hatching (dph). The larvae started to feed on rotifers at day 3 to day 7. Feeding on a commercial diet was started from day-8 onwards. Specific trypsin and chymotrypsin activities feed with rotifer were 0.011 U/mg protein and 0.003 U/mg protein at day 7, respectively; then the specific activities feed with dry food reached a maximum level at 33 dph (0.028 U/mg protein and 0.028 U/mg protein, respectively) (P<0.05) compared to live prey. The elevated alkaline proteases activity can be related to adaptation of larvae to digest protein content in the food. Specific lipase activity was 0.0006 U/mg protein at 7 dph; then the activity feed with dry food reached a maximum level at 15 dph (0.0011 U/mg protein) (P<0.05) compared to live prey. Specific α-amylase activity feed with rotifer was 85.86 U/mg protein on the 7 dph; consequently, its specific activity reached a maximum level at 15 dph (128.77 U/mg protein) (P<0.05). Specific alkaline phosphatase and aminopeptidase N activities feed with rotifer were 6 U/mg protein and 0.0106 U/mg protein at day 7, respectively; then the specific activities feed with dry food reached a maximum level at 33 dph (28.66 U/mg protein and 0.58 U/mg protein, respectively) (P<0.05) compared to live prey

Histology of intestine and fatty acid profile of Pacific white shrimp (Litopenaeus vannamei) effected by dietary inulin

The effects of inulin were studied on the growth indices, intestinal morphology as well as fatty acid profile of the Pacific white shrimp, Litopenaeus vannamei with average weight 3.21±0.03 g for 5 weeks. The experiment was carried in triplicate, was conducted in circular PVC tanks of 300 L capacity with 25 shrimp per tank at the Aquaculture Center (Delvar, Bushehr province). Inulin was added to the diets at a 2 levels (0 and 2 percent). The shrimp were fed the experimental diets to visual satiety five times a day at 08:00, 12:00, 16:00, 20:00 and 24:00 h. No significant differences in growth performances (such as survival, feed conversion ratio (FCR), specific growth rate (SGR), Protein efficiency ratio (PER)) was observed, however, Dietary inulin brought about significantly improved 20:3n3 fatty acid content between the two treatments (P>0.05). Intestine epithelium cells height in the abdominal sections significantly (P< 0.05) were higher in shrimp fed by dietary inulin. The results of this study showed that supplement of 2% of inulin has positive effects on fatty acid profile and intestinal morphology in Litopenaeus vannamei

Supplementary Material# 1; Supplementary Material# 2; Supplementary Material# 3 from Sensitive colorimetric assay using insulin G-quadruplex aptamer arrays on DNA nanotubes coupled with magnetic nanoparticles

Circular dichroism spectroscopy of G-rich aptamer-insulin interaction; Atomic force microscopy of DNTs coupled with magnetic nanoparticles; Standard curve with a residual plot of insulin detection via the aptamers array based on a serial concentration of insulin (1.56-100 µIU/ml) with 2 µM G-rich aptame