Volume 65, 2013
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ItemEffects of Dietary Protein Level on Growth Performance, Muscle Composition, Blood Composition, and Digestive Enzyme Activity of Wuchang Bream (Megalobrama amblycephala) Fry( 2013)The purpose of this study was to determine the dietary protein requirement and effects of dietary protein level on growth performance, muscle composition, blood composition, and digestive enzyme activity in Wuchang bream fry. Five isoenergetic and isolipidic semi-purified diets were formulated to contain 28%, 30%, 32%, 34%, or 36% (dry matter) dietary protein. Diets were fed to triplicate groups of 25 fishes (16.08±0.03 g) to near satiation three times a day in a closed recirculation system for 10 weeks. Weight gain, specific growth rate, and feed conversion ratio significantly improved as the dietary protein content increased up to 34%. The protein efficiency ratio, hepatosomatic index, and viscerosomatic index significantly dropped as the dietary protein rose while the Fulton condition factor was positively correlated to the dietary protein level. Increased dietary protein resulted in increased muscle protein content and decreased lipid content. Red blood cell, hemoglobin, and hematocrit counts increased significantly with the increase in dietary protein. Serum triiodothyronine and thyroxine significantly rose as the dietary protein rose but serum aspartate aminotransferase significantly dropped. Intestinal protease and amylase activity rose significantly with the increase in dietary protein while lipase tended to drop. On the basis of broken-line regression analysis of weight gain and FCR, the dietary protein requirement of Wuchang bream fry is 32-33%.
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ItemUsing Microsatellites to Assess Genetic Variation in a Selective Breeding Program of Chinese Bay Scallop (Argopecten irradians irradians)( 2013)This study aimed to improve our understanding of the genetics of the Chinese bay scallop (Argopecten irradians irradians), one of the most important maricultured shellfish in China. Ten polymorphic microsatellite loci were examined to assess the allelic diversity, heterozygosity, and genetic variation between two domesticated populations selected for fast growth in breeding programs, and their base population. Forty-one alleles were found throughout the loci and the mean number of alleles per locus ranged 3.30-3.50. The average heterozygosity ranged 0.38-0.45, whereas the polyamorphic information content ranged 0.1504-0.7518. Genetic differences between the three populations were detected based on the number of alleles per locus, effective number of alleles, Shannon index, inbreeding coefficient (Fis), p values, genetic distance, and pairwise Fst values. There was no significant loss of genetic variability in the breeding program but changes in gene frequencies were detectable over the populations, implying that thea loci were saffected by the pressures of selective culture.
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ItemUsing Microsatellites to Assess Genetic Variation in a Selective Breeding Program of Chinese Bay Scallop (Argopecten irradians irradians)( 2013)This study aimed to improve our understanding of the genetics of the Chinese bay scallop (Argopecten irradians irradians), one of the most important maricultured shellfish in China. Ten polymorphic microsatellite loci were examined to assess the allelic diversity, heterozygosity, and genetic variation between two domesticated populations selected for fast growth in breeding programs, and their base population. Forty-one alleles were found throughout the loci and the mean number of alleles per locus ranged 3.30-3.50. The average heterozygosity ranged 0.38-0.45, whereas the polyamorphic information content ranged 0.1504-0.7518. Genetic differences between the three populations were detected based on the number of alleles per locus, effective number of alleles, Shannon index, inbreeding coefficient (Fis), p values, genetic distance, and pairwise Fst values. There was no significant loss of genetic variability in the breeding program but changes in gene frequencies were detectable over the populations, implying that thea loci were saffected by the pressures of selective culture.
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ItemUse of Red and Blue Light-Emitting Diodes (LED) and Fluorescent Lamps to Grow Microalgae in a Photobioreactor( 2013)High oil content microalgae are a source for biofuel production. They can be produced in open ponds or closed photobioreactors. To efficiently grow such microalgae, illumination for photosynthesis, CO2 consumption, and the pH and nutrient content of the growth medium must be monitored and precisely controlled. In a closed photobioreactor, illumination is the most critical parameter because it is the most expensive factor of algae production and must be operated 24 h per day. In this research, Chlorella kessleri (UTEX 398) microalgae were grown in photobioreactors. All parameters were identical, except the source and intensity of the illumination. The light sources included red light-emitting diodes (LED), blue LED, and fluorescent lights. Growth of the microalgae was observed for seven days and the effects of the three illumination sources on cell count, cell weight, and cell size were determined. In the first experiment, in which the current of all three light sources was the same, red LED produced the highest number of cells with the highest weight while blue LED light produced the largest cells. In the second experiment, in which the light intensity was the same for all three light sources, the highest weight was again achieved with the red LED. Thus, we suggest that most advantageous production system may be to use a red light initially to produce the desired cell concentration, then switch to a blue light to increase cell size.
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ItemEffects of Intensive and Semi-Intensive Rearing on Growth, Survival, and V-Shaped (Lordotic) Skeletal Deformities in Juvenile Gilthead Sea Bream (Sparus aurata)( 2013)Intensive production can reduce production costs and improve efficiency of larvae culture. This study compared the effects of intensive and semi-intensive production on growth, survival, and V-shaped skeletal deformities in juvenile gilthead sea bream (Sparus aurata). At the end of the 50-day study, survival was 68.01±0.8%, mean weight was 1.32±0.03 g, and lordosis was 32% among juveniles raised in the intensive system. Survival and mean weight were significantly higher, 92.06±1.1% and 1.61±0.02 g, respectively, among juveniles raised in the semi-intensive system, and none had lordosis (p<0.05). Results suggest that semi-intensive systems are more advantageous than intensive for rearing sea bream juveniles.
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ItemImproved Resistance to Vibrio parahaemolyticus in Black Tiger Shrimp Penaeus monodon Treated with Streptococcus phocae PI80 and Bacillus subtilis( 2013)The aim of the study was to establish the immune response induced by Streptococcus phocae PI80, Bacillus subtilis, and commercial probiotics (Uni-Ecosense, EcoForce, Uni-Hatch) in the shrimp, Penaeus monodon. Total hemocyte count, phenoloxidase activity, nitroblue tetrazolium (NBT) reductase assay, phagocytic activity, and disease resistance was evaluated for 30 days. Total hemocyte count, phenoloxidase activity, NBT reductase assay, and phagocytic activity significantly increased in juveniles and adults treated with S. phocae PI80, a mixture of S. phocae PI80 and B. subtilis, or a commercial probiotic, but there were no significant differences in live weight of shrimps treated with probiotics or the control. Treatment with S. phocae PI80 plus B. subtilis enhanced survival of shrimps challenged with Vibrio parahaemolyticus. Our study demonstrates that administration of S. phocae PI80+B. subtilis at 4.6 х 108 CFU/ml water induced immune modulation, enhanced immune ability, and increased resistance to V. parahaemolyticus in juvenile and adult black tiger shrimp.
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ItemVegetable Products as Dietary Pigment Sources for Juvenile Goldfish, Carassius auratus( 2013)Amaranthus leaf meal, moringa leaf meal, and red chili powder were chemically analyzed and evaluated as carotenoid sources in diets for juvenile goldfish, Carassius auratus. The fish readily accepted all test diets, indicating good palatability of the tested ingredients. In a 56-day growth trial, all growth performance indicators except survival significantly varied (p<0.05) between dietary treatments. The highest weight gain (1.19 g) was achieved by fish fed the diet containing krill meal (positive control diet), but this weight gain did not significantly differ from that of fish fed the diet containing red chili powder. Total carotenoids were significantly highest (p<0.05) in fish fed the diet containing red chili powder (2.07 μg/g) and very low in fish fed the diet containing no pigment supplement (negative control). Growth, skin coloration, and total carotenoids in the tissue were satisfactory in fish fed the diets containing amaranthus or moringa leaf meal.
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ItemEffect of Marine Red Yeast Rhodosporidium paludigenum on Antioxidant-Related Gene Expression in Litopenaeus vannamei( 2013)The effects of orally-administered dry and live marine red yeast Rhodosporidium paludigenum on antioxidant-related gene expression in the hepatopancreas and hemocytes of Litopenaeus vannamei were investigated by RT-PCR. In the hepatopancreas of L. vannamei fed dry yeast, manganese superoxidate dismutase (SODMn) and catalase (CAT) were enhanced while glutathione peroxidase (GPx) and ferritin remained at the same levels as in the control group. In the hepatopancreas of L. vannamei fed live yeast, SODMn and ferritin were higher than in the control. In hemocytes of L. vannamei fed dry yeast, SODMn was lower, ferritin was similar, and CAT and GPx fluctuated, in comparison to the control. In hemocytes of L. vannamei fed live yeast, SODMn was lower, ferritin was higher, and CAT and GPx tended to be lower than in the control group. Results suggest that consumption of the marine red yeast, R. paludigenum, can stimulate antioxidant gene expression in the hepatopancreas of shrimp.
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ItemImpact of Potential Food Sources on the Life Table of the Cladoceran, Moina macrocopa( 2013)The zooplankton Moina macrocopa was cultured with three kinds of emulsified lipid media (Selco®, squid oil, canola oil) and two kinds of fish wastes (fish pellets and fish feces) to determine the impact of these food sources on its population dynamics. All diets were provided at five levels: 0.0625, 0.125, 0.25, 0.5, and 1.0 g/l. For all diets, life history parameters showed the highest values at the lowest concentrations, i.e., <0.125 g/l. Overall demographic performance was better in M. macrocopa fed the emulsified liquid diets than M. macrocopa raised in the control treatment (dechlorinated water; no diet) but not as good as in M. macrocopa fed the fish wastes. Fish feces was excellent for propagating M. macrocopa. In conclusion, using fish wastes to cultivate M. macrocopa could be an inexpensive and sustainable cultivation approach.
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ItemEnhancement of Growth Performance and Pigmentation in Red Oreochromis mossambicus Associated with Dietary Intake of Astaxanthin, Paprika, or Capsicum( 2013)Diets for tilapia, Oreochromis mossambicus, were supplemented with astaxanthin, paprika, or capsicum to determine their effects on growth performance and pigmentation. Seven isonitrogenous (37% crude protein) and isoenergetic (18 kJ/g) diets were formulated to contain 40 or 60 mg carotenoid per kg diet. Triplicate groups of 210 fish were stocked in 21-l plastic boxes and fed one of the three experimental diets or the control diet for 45 days. Significantly better final weight, weight gain, specific growth rate, and food conversion ratio were obtained with the diets containing 40 or 60 mg/kg paprika than with control diet (p<0.05). In general, the carotenoid-supplemented diets significantly increased the values of redness (a*), yellowness (b*), and chroma (C*), and decreased the values of lightness (L*) and hue (Hoab) on the tail, body, and head areas (p<0.05). Results show that paprika or capsicum oleoresin can be used as an alternative natural carotenoid source in O. mossambicus diets to ensure good pigmentation, better growth, and feed utilization.